0000950170-24-034974 | 10-K | XBRL Viewer

Net Loss per Share

12 Months Ended

Dec. 31, 2023

12. Net Loss per Share

Basic and diluted net loss per share attributed to common stockholders is calculated by dividing net loss attributed to common stockholders by the weighted average number of common shares outstanding during the period, without consideration for common stock equivalents. The Company’s potentially dilutive shares, which include preferred stock, unvested RSAs, RSUs, and options to purchase common stock, are considered to be common stock equivalents and are only included in the calculation of diluted net loss per share when their effect is anti-dilutive. Potentially dilutive common shares have been excluded from the diluted net loss per common share computations in all periods presented because such securities have an anti-dilutive effect on net loss per common share due to the Company’s net loss. There are no reconciling items used to calculate the weighted-average number of total common shares outstanding for basic and diluted net loss per common share.

The following outstanding potentially dilutive shares were excluded from the computation of diluted net loss per share attributable to common stockholders:


	Year Ended December 31,
		2023		2022
Redeemable convertible preferred stock			—		12,493,879
Restricted stock			90,740		181,480
Unvested RSUs			102,945		—
Options to purchase common stock			3,374,282		2,529,982
Total			3,567,967		15,205,341

Fair Value of Financial Assets and Liabilities - Schedule of financial assets and liabilities measured on recurring basis at fair value (Detail) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Financial assets:
Total financial assets	$ 92,730	$ 56,950
Contingent consideration [Member]
Financial liabilities:
Total financial liabilities	916	5,994
Fair value recurring basis [Member]
Financial assets:
Money market funds	15,635	9,238
Restricted cash	116	382
U.S. government and agency securities	76,979	47,330
Total financial assets	92,730	56,950
Financial liabilities:
Total financial liabilities	916	5,994
Fair value recurring basis [Member] \| Contingent consideration [Member]
Financial liabilities:
Contingent consideration	916	5,994
Fair value recurring basis [Member] \| Level 1 [Member]
Financial assets:
Money market funds	15,635	9,238
Restricted cash	116	382
U.S. government and agency securities	76,979	30,649
Total financial assets	92,730	40,269
Fair value recurring basis [Member] \| Level 2 [Member]
Financial assets:
U.S. government and agency securities		16,681
Total financial assets		16,681
Fair value recurring basis [Member] \| Level 3 [Member]
Financial liabilities:
Total financial liabilities	916	5,994
Fair value recurring basis [Member] \| Level 3 [Member] \| Contingent consideration [Member]
Financial liabilities:
Contingent consideration	$ 916	$ 5,994

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Current assets:
Cash and cash equivalents	$ 17,798	$ 34,731
Restricted cash	116	382
Short-term investments	76,979	47,330
Accounts receivable - collaboration agreement	194	8,728
Prepaid expenses	4,655	5,081
Other current assets	2,812	1,749
Total current assets	102,554	98,001
Other assets, noncurrent	1,143	2,582
Operating lease right of use assets	2,766	4,631
Property and equipment, net	6,352	9,724
Total assets	112,815	114,938
Current liabilities:
Accounts payable	36	3,435
Accrued expenses and other current liabilities	9,909	14,287
Operating lease liability, current	2,025	1,961
Deferred revenue, current	0	15,144
Total current liabilities	11,970	34,827
Deferred revenue, noncurrent	0	4,162
Operating lease liability, noncurrent	1,189	3,205
Other liabilities, noncurrent	989	2,267
Total liabilities	14,148	44,461
Redeemable convertible preferred stock
Preferred stock ,shares authorized, issued and outstanding	0	171,944
Stockholders' equity (deficit)
Preferred stock, $0.001 par value; 10,000,000 and 0 shares authorized at December 31, 2023 and 2022, respectively, 0 shares issued and outstanding at December 31, 2023 and 2022, respectively	0	0
Common stock, $0.001 par value; 490,000,000 and 147,892,358 shares authorized, 23,099,335 and 2,915,757 shares issued and outstanding as of December 31, 2023 and 2022, respectively	23	3
Additional paid-in capital	275,521	20,501
Accumulated other comprehensive loss	(119)	(413)
Accumulated deficit	(176,758)	(121,558)
Total stockholders' equity (deficit)	98,667	(101,467)
Total liabilities, redeemable convertible preferred stock and stockholders' equity (deficit)	112,815	114,938
Series A redeemable convertible preferred stock [Member]
Redeemable convertible preferred stock
Preferred stock ,shares authorized, issued and outstanding	0	8,643
Series B-1 redeemable convertible preferred stock [Member]
Redeemable convertible preferred stock
Preferred stock ,shares authorized, issued and outstanding	0	12,611
Series B-2 redeemable convertible preferred stock [Member]
Redeemable convertible preferred stock
Preferred stock ,shares authorized, issued and outstanding	0	28,860
Series C redeemable convertible preferred stock [Member]
Redeemable convertible preferred stock
Preferred stock ,shares authorized, issued and outstanding	0	42,100
Series D redeemable convertible preferred stock [Member]
Redeemable convertible preferred stock
Preferred stock ,shares authorized, issued and outstanding	$ 0	$ 79,730

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Operating Activities
Net loss	$ (55,200)	$ (30,834)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation expense	4,216	4,368
Loss on disposal of property and equipment	324	(100)
Depreciation and amortization	2,798	3,901
Impairment of long-lived assets	1,582	497
Moffitt performance-based common stock award		2,051
Accretion of premium on short term investments	(2,059)	(98)
Change in fair value of contingent consideration liability	109	7,019
Changes in operating assets and liabilities:
Accounts receivable - collaboration agreement	8,534	(2,013)
Prepaid expenses	426	(197)
Other current assets	(1,063)	548
Operating lease liabilities	(87)	(1,735)
Accounts payable	(3,399)	3,407
Change in contingent consideration liability	(1,477)
Accrued compensation and other accrued liabilities	(1,122)	(4,879)
Other non-current assets	(437)
Other non-current liabilities	9
Deferred revenue	(19,306)	(53,097)
Net cash flows used in operating activities	(66,152)	(71,062)
Investing Activities
Proceeds from maturities of short-term investments	82,500	49,750
Purchase of short-term investments	(109,796)	(59,512)
Proceeds from sale of property and equipment	452
Purchases of property and equipment	(1,249)	(5,170)
Net cash flows used in investing activities	(28,093)	(14,932)
Financing Activities
Proceeds from issuance of common stock, net of issuance costs	77,839
Payment of contingent consideration related to Myst milestone	(898)	(2,813)
Proceeds from exercise of stock options	105	157
Net cash flows provided by (used in) financing activities	77,046	(2,656)
Net decrease in cash, cash equivalents and restricted cash	(17,199)	(88,650)
Cash, cash equivalents and restricted cash at beginning of the period	35,113	123,763
Cash, cash equivalents and restricted cash at end of the period	17,914	35,113
Supplemental Disclosure of Cash Flow Information:
Cash paid for income taxes	100	83
Supplemental Disclosure of Non-Cash Investing and Financing Activities:
Accretion of redeemable convertible preferred stock	39	190
Additions to ROU assets obtained from new operating leases		4,218
Equipment purchases included in accrued expenses	535
Conversion of convertible preferred stock to common stock upon closing of IPO	171,983
Issuance of common stock to settle Myst contingent consideration liability	$ 2,812	$ 5,000

Equity Based Compensation - Schedule of Stock Based Compensation for Stock Awards (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation	$ 4,216	$ 4,368
Research and development [Member]
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation	2,274	2,167
General and administrative [Member]
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation	$ 1,942	$ 2,201

Legal Proceedings

12 Months Ended

Dec. 31, 2023

Commitments and Contingencies Disclosure [Abstract]

Legal Proceedings

13. Legal Proceedings

The Company is not a party to any material legal matters or claims and does not have contingency reserves established for any litigation liabilities as of the years ended December 31, 2023 and 2022, respectively.

Fair Value of Financial Assets and Liabilities

12 Months Ended

Dec. 31, 2023

Fair Value Disclosures [Abstract]

Fair Value of Financial Assets and Liabilities

3. Fair Value of Financial Assets and Liabilities

As of December 31, 2023 and 2022, the Company’s restricted cash which is maintained as collateral in connection with its New York and San Diego facility leases, (See Note 2 – Summary of Significant Accounting Policies for additional information) are valued using Level 1 inputs. The Company’s highly liquid money market funds included within cash equivalents, restricted cash and U.S. treasury securities are valued using Level 1 inputs. The Company classifies its federal agency securities as Level 2. There were no transfers in or out of Level 1 and Level 2 during the periods presented. U.S. treasury securities are bonds issued by the U.S. government and are fully backed by the U.S. government. Given the frequency at which U.S. treasury securities trade and the accessibility of observable, quoted prices for such assets in active markets, they are recognized as Level 1 assets. Federal agency securities are bonds and notes issued by government-sponsored enterprises, including Fannie Mae, Freddie Mac and the Federal Home Loan Bank. Since Federal agency securities typically do not trade as frequently as U.S. government agency securities and no exchange exists to price such investments, they are recognized as Level 2 assets.

The Company had $0.9 million and $6.0 million in contingent consideration liabilities as of December 31, 2023 and 2022, respectively, related to the Myst Merger Agreement. The contingent consideration balances are comprised of one potential milestone payment as of December 31, 2023 and two separate potential milestone payments as well as the remaining unpaid liability of $2.2 million from the milestone achievement as of December 31, 2022 with each measured at fair value (See Note 7—Asset Acquisition for additional information). The fair value of the contingent consideration is estimated based on the monetary value of the milestone discounted for the likelihood of achieving the milestone and a present value factor based on the timing of when the milestone is expected to be achieved. The value for the contingent consideration balance is based on significant inputs not observable in the market which represents a Level 3 measurement within the fair value hierarchy. There were no transfers in or out of Level 3 during the periods presented.

The following tables represent a summary of the financial assets and liabilities that are measured on a recurring basis at fair value (in thousands):


	December 31, 2023
	Level 1		Level 2		Level 3		Fair Value
Financial assets:
Money market funds	$	15,635					$	15,635
Restricted cash(1)		116		—		—		116
U.S. government and agency securities(2)		76,979		—		—		76,979
Total financial assets	$	92,730	$	—	$	—	$	92,730
Financial liabilities:
Contingent consideration(3)	$	—	$	—	$	916	$	916
Total financial liabilities	$	—	$	—	$	916	$	916


	December 31, 2022
	Level 1		Level 2		Level 3		Fair Value
Financial assets:
Money market funds	$	9,238	$	—	$	—	$	9,238
Restricted cash(1)		382		—		—		382
U.S. government and agency securities(2)		30,649		16,681		—		47,330
Total financial assets	$	40,269	$	16,681	$	—	$	56,950
Financial liabilities:
Contingent consideration(3)	$	—	$	—	$	5,994	$	5,994
Total financial liabilities	$	—	$	—	$	5,994	$	5,994

(1)

Restricted cash serves as deposits for the Company’s San Diego office lease as of December 31, 2023 and New York and San Diego office leases as of December 31, 2022.

(2)

Included in short-term investments on the consolidated balance sheets and are classified as available-for sale debt securities.

(3)

Contingent consideration related to the Myst Merger Agreement.

The following significant unobservable inputs were used in the valuation of the contingent consideration payable to the sole common stockholder of Myst pursuant to the Myst Merger Agreement:


	Fair Value as of
Contingent Consideration Liability	December 31, 2023		Valuation Technique	Unobservable Input	Range
	(in thousands)
Milestone payment for first	$	916	Discounted cash flow	Likelihood of occurrence	10%
registrational study (see Note 7				Discount rate	25%
- Asset Acquisition for additional information)				Expected term (in years)	3.5

	Fair Value as of
Contingent Consideration Liability	December 31, 2022		Valuation Technique	Unobservable Input	Range
	(in thousands)
Milestone payments	$	5,994	Discounted cash flow	Likelihood of occurrence	20% - 100%
				Discount rate	22%
				Expected term (in years)	0.25 - 2.75

The following table reflects the activity for the Company’s contingent consideration, measured at fair value using Level 3 inputs (in thousands):


Contingent consideration at December 31, 2022	$	5,994
Changes in the fair value of contingent consideration		109
Cash payment of Myst milestone		(2,375	)
Equity issuance related to milestone achievement		(2,812	)
Contingent consideration at December 31, 2023		916

The following tables show the Company’s cash, cash equivalents and available-for-sale securities by significant investment category (in thousands):


	December 31, 2023
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value
Level 1: Money market funds	$	15,635	$	—	$	—	$	15,635
Restricted cash		116		—		—		116
U.S. government securities		76,875		104		—		76,979
Total financial assets	$	92,626	$	104	$	—	$	92,730
Classified as:
Cash and cash equivalents							$	15,635
Restricted cash								116
Short-term investments								76,979
							$	92,730


	December 31, 2022
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
Level 1: Money market funds	$	9,238	$	—	$	—		$	9,238
Restricted cash		382		—		—			382
U.S. government securities		30,761		—		(112	)		30,649
Level 2: U.S. agency securities		16,759		—		(78	)		16,681
Total financial assets	$	57,140	$	—	$	(190	)	$	56,950
Classified as:
Cash and cash equivalents								$	9,238
Restricted cash									382
Short-term investments									47,330
								$	56,950

As of December 31, 2023, 0 of 28 of our available-for-sale debt securities were in a gross unrealized loss position. As of December 31, 2022, 23 out of 24 of our available-for-sale debt securities were in an aggregate gross unrealized loss position of $0.2 million with an aggregate fair value of $45.3 million. While short-term investments are available-for-sale, it is not more likely than not that the Company will be required to sell the investments before recovery of their amortized cost bases, which may be maturity. All short-term investments currently held have maturities of less than one year.

The Company reviews short-term investments for impairment during each reporting period. Credit losses are recognized up to the amount equal to the difference between the fair value and the amortized cost basis and recorded as an allowance for credit losses in the consolidated balance sheets with a corresponding adjustment to earnings. Unrealized losses that are not related to credit losses are recognized in accumulated other comprehensive loss. There were no unrealized losses in the Company's investment portfolio at December 31, 2023. Unrealized losses were not significant for the investments held in the Company’s portfolio as of December 31, 2022 and the Company considered the decline in market value for these securities to be primarily attributable to economic and market conditions rather than credit-related factors. The Company considered the risk-profile of the counterparties under ASU 2016-13, noting that any credit risk associated with such entities is either zero or near zero. There were no impairment losses or expected credit losses related to its short-term investments during the twelve months ended December 31, 2023 and 2022.

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

Income Taxes - Schedule of Income Tax Provision (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Current:
Federal	$ (522)	$ 80
State taxes	236	61
Deferred:
Total tax provision (benefit)	$ (286)	$ 141

- Definition

Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

+ References + Details

Income Taxes - Schedule of Aggregate Changes in the Balances of the Company's Gross Unrecognized Tax Benefits (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2023 USD ($)
Income Tax Disclosure [Abstract]
December 31, 2022	$ (857)
Increases in balances related to tax positions taken during a prior period	(541)
Increases in balances related to tax positions taken during the current period	(799)
December 31, 2023	$ (2,197)

Fair Value of Financial Assets and Liabilities - Additional Information (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2023 USD ($) Security	Dec. 31, 2022 USD ($) Security
Fair Value Disclosures [Line Items]
Unpaid liability on milestone acheivement		$ 2,200
Asset impairment charges	$ 0	$ 0
Investment, Type [Extensible Enumeration]	Short-Term Investments [Member]	Short-Term Investments [Member]
Available-for-sale debt securities an aggregate unrealized loss position		$ 200
Available-for-sale debt securities an aggregate fair value		$ 45,300
Maximum [Member]
Fair Value Disclosures [Line Items]
Number of available-for-sale debt securities in gross unrealized loss position \| Security	28	24
Minimum [Member]
Fair Value Disclosures [Line Items]
Number of available-for-sale debt securities in gross unrealized loss position \| Security	0	23
Myst [Member]
Fair Value Disclosures [Line Items]
Contingent consideration liability	$ 900	$ 6,000

Income Taxes (Tables)

12 Months Ended

Dec. 31, 2023

Income Tax Disclosure [Abstract]

Schedule of Components of Net Loss Before Income Taxes

The following table represents the components of net loss before income taxes (in thousands):


	Year Ended December 31,
	2023			2022
Domestic	$	(52,765	)	$	(22,065	)
Foreign		(2,721	)		(8,628	)
Loss before provision for income taxes	$	(55,486	)	$	(30,693	)

Schedule of Income Tax Provision

The income tax provision consisted of the following (in thousands):


	Year Ended December 31,
	2023			2022
Current:
Federal	$	(522	)	$	80
State taxes		236			61
Deferred:
Federal					—
State					—
Total tax provision (benefit)	$	(286	)	$	141

Schedule of Reconciliation of the Expected Provision for Income Tax Recovery

The reconciliation of the expected provision for income tax recovery to the actual provision for income tax expense reported is as follows (in thousands):


	Year Ended December 31,
	2023			2022
Loss before income taxes	$	(55,486	)	$	(30,693	)
Statutory rate		21	%		21	%
Expected income tax recovery		(11,652	)		(6,446	)
Permanent differences		211			260
Foreign rate differential		(149	)		(462	)
Canada ITC credits		(715	)		(1,617	)
Federal R&D credit		(1,776	)		(1,637	)
Unrecognized tax benefit		(13	)		22
State tax		3,348			(2,422	)
Myst transaction		210			1,877
Other		1,337			(4	)
Change in valuation allowance		9,525			10,570
R&D credit carryback claim		(612	)		—
Provision for income taxes (benefit) expenses	$	(286	)	$	141

Schedule of Components of the Company's Deferred Income Tax Assets

The significant components of the Company’s deferred income tax assets are as follows (in thousands):


	Year Ended December 31,
	2023			2022
Deferred tax assets:
Credits	$	10,874		$	7,960
Accruals		125			108
Stock compensation		898			1,111
State taxes		1			33
Right-of-use lease liability		680			1,319
Property and equipment		—			144
Intangibles		20,726			16,858
Tax losses		14,783			7,253
Deferred revenue		—			5,290
Total deferred tax assets	$	48,087		$	40,076
Deferred tax liability:
Right-of-use lease asset	$	(588	)	$	(1,174	)
Property and equipment		(734	)		(1,665	)
Unrealized gains/losses		(3	)		—
Total deferred tax liability	$	(1,325	)	$	(2,839	)
Valuation allowance		(46,762	)		(37,237	)
Net deferred tax assets	$	0		$	0

Schedule of Aggregate Changes in the Balances of the Company's Gross Unrecognized Tax Benefits

The aggregate changes in the balances of the Company’s gross unrecognized tax benefits during 2023 were as follows (in thousands):


December 31, 2022	$	(857	)
Increases in balances related to tax positions taken during a prior period		(541	)
Increases in balances related to tax positions taken during the current period		(799	)
Decreases in balances related to tax positions tax during the prior period		—
December 31, 2023	$	(2,197	)

Redeemable Convertible Preferred Stock and Stockholders' Equity - Additional Information (Detail) $ / shares in Units, $ / shares in Units, $ in Millions, $ in Millions	1 Months Ended				12 Months Ended	13 Months Ended
	Jun. 30, 2021 USD ($) $ / shares shares	Jan. 31, 2019 USD ($) $ / shares shares	Nov. 30, 2018 USD ($) $ / shares shares	Oct. 31, 2016 USD ($) shares	Dec. 31, 2023 $ / shares shares	Oct. 31, 2016 CAD ($) $ / shares shares	Oct. 31, 2016 USD ($) shares	Aug. 15, 2023 $ / shares	Jul. 25, 2023 $ / shares shares	Dec. 31, 2022 $ / shares shares	Oct. 31, 2016 $ / shares
Class of Stock [Line Items]
Shares issued, price per share \| $ / shares								$ 12
Common stock, par or stated value per Share \| $ / shares					$ 0.001				$ 0.001	$ 0.001
Common stock, shares authorized					490,000,000				490,000,000	147,892,358
Common Stock [Member]
Class of Stock [Line Items]
Conversion of redeemable convertible preferred stock into common stock					12,493,879
Series A Redeemable Convertible Preferred Stock [Member]
Class of Stock [Line Items]
Number of stock classified as temporary equity issued during the period						11,250,000	11,250,000
Shares issued, price per share \| (per share)						$ 1					$ 0.74
Foreign exchange rate						1.344					1.344
Value of new stock classified as temporary equity issued during the period						$ 10.9	$ 8.1
Series B1 Redeemable Convertible Preferred Stock [Member]
Class of Stock [Line Items]
Number of stock classified as temporary equity issued during the period				16,285,156
Shares issued, price per share \| $ / shares											$ 0.77
Proceeds from Issuance of redeemable convertible preferred stock \| $				$ 12.3
Series B2 Redeemable Convertible Preferred Stock [Member]
Class of Stock [Line Items]
Number of stock classified as temporary equity issued during the period			25,065,538
Shares issued, price per share \| $ / shares			$ 1.15
Proceeds from Issuance of redeemable convertible preferred stock \| $			$ 28.9
Series C Redeemable Convertible Preferred Stock [Member]
Class of Stock [Line Items]
Number of stock classified as temporary equity issued during the period		17,905,288
Shares issued, price per share \| $ / shares		$ 2.35
Proceeds from Issuance of redeemable convertible preferred stock \| $		$ 41.8
Series D Redeemable Convertible Preferred Stock [Member]
Class of Stock [Line Items]
Number of stock classified as temporary equity issued during the period	29,285,356
Shares issued, price per share \| $ / shares	$ 2.73
Proceeds from Issuance of redeemable convertible preferred stock \| $	$ 79.8

Agreements (Tables)

12 Months Ended

Dec. 31, 2023

Collaborative Arrangement Disclosure [Abstract]

Schedule Of Transaction Price Allocated To Programs Performance Obligation

The Company determined that the notice of termination on June 13, 2022, represented a modification of the arrangement under ASC 606 and that the transaction price should be updated and re-allocated to the Development Program Performance Obligation and the Discovery Program Performance Obligation based on their standalone selling prices, as follows:


Performance Obligations	Price Pre- Modification	Price at Modification
Development Program	$166.3 million	$134.3 million
Discovery Program	$26.3 million	$21.2 million
Total	$192.6 million	$155.5 million

Property and Equipment, Net

12 Months Ended

Dec. 31, 2023

Property, Plant and Equipment [Abstract]

Property and Equipment, Net

4. Property and Equipment, Net

Property and equipment, net consist of the following (in thousands):


	December 31,			December 31,
	2023			2022
Computer equipment and software	$	—		$	376
Laboratory equipment		11,043			12,901
Furniture		690			758
Leasehold improvements		1,308			1,308
		13,041			15,343
Less: Accumulated depreciation and amortization		(6,689	)		(5,619	)
Total property and equipment, net	$	6,352		$	9,724

Property and equipment depreciation and amortization expense for the twelve months ended December 31, 2023 and 2022, was $2.8 million and $2.2 million, respectively.

The gain (loss) on disposal of property and equipment was ($0.3) million and $0.1 million for the twelve months ended December 31, 2023 and 2022, respectively.

During the twelve months ended December 31, 2023, the Company's stock price and resulting market capitalization experienced a significant, sustained decline. Accordingly, the Company assessed our long-lived assets, including its property, plant and equipment and operating lease assets for impairment. For its property and equipment, the Company performed a recoverability test by comparing the future cash flows attributable to the property and equipment to the carrying value of the assets. Based on this evaluation, the Company determined that the property and equipment with a carrying value of $7.9 million was no longer recoverable. As a result, the Company recognized an impairment charge of $1.6 million which was calculated as the difference between fair value of the assets and its carrying value. The fair value was based on the indirect cost approach which considers the cost of constructing a new asset less depreciation and obsolescence. the fair value ws determined using level 3 inputs. The impairment charge was recorded as research and development expenses in the consolidated statement of operations and comprehensive loss for the twelve months ended December 31, 2023.

Agreements - Additional Information (Detail) - USD ($) $ in Thousands						1 Months Ended		6 Months Ended	12 Months Ended
	Aug. 15, 2023	Feb. 27, 2023	Jun. 01, 2022	Apr. 30, 2020	Nov. 30, 2019	Apr. 30, 2020	Nov. 30, 2019	Jun. 30, 2022	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Inflow From Issuance Of Intangible Asset
Additional revenue recognized on change in contract modification									$ 19,306	$ 73,300
Number of new stock issued during the period	651,608
Takeda Agreement [Member]
Inflow From Issuance Of Intangible Asset
Percentage of share of operating profit or loss					30.00%
Performance Obligations											$ 192,600
Additional revenue recognized on change in contract modification								$ 31,600
Deferred revenue									0	19,300
Revenue from collaborative arrangement									$ 19,300	$ 73,300
Collaborative Arrangement, Revenue Not from Contract with Customer, Statement of Income or Comprehensive Income [Extensible Enumeration]									Additional revenue recognized on change in contract modification	Additional revenue recognized on change in contract modification
Collaborative arrangement additional consideration receivable for license option					$ 15,000		$ 15,000
Revenue, performance obligation fixed aggregate consideration					80,000		80,000
Revenue, performance obligation fixed consideration Non refundable upfront payment received							50,000
Revenue, performance obligation fixed consideration Non refundable payment received						$ 30,000
Estimated compensation earning from project expense sharing					58,600		58,600				$ 92,600
Takeda Agreement [Member] \| Development Program [Member]
Inflow From Issuance Of Intangible Asset
Receivables related to reimbursable costs									$ 200	$ 8,700
Takeda Agreement [Member] \| Development Program [Member] \| First Milestone Payment [Member]
Inflow From Issuance Of Intangible Asset
Milestone payment receivable					20,000		20,000
Performance Obligations					20,000		20,000
Takeda Agreement [Member] \| Development Program [Member] \| Second Milestone Payment [Member]
Inflow From Issuance Of Intangible Asset
Milestone payment receivable					15,000		15,000
Takeda Agreement [Member] \| Development Program [Member] \| Third Milestone Payment [Member]
Inflow From Issuance Of Intangible Asset
Milestone payment receivable					15,000		15,000
Takeda Agreement [Member] \| Discovery Program [Member]
Inflow From Issuance Of Intangible Asset
Equity purchase commitments by counter party					20,000		20,000
Takeda Pharmaceutical Company Limited [Member] \| Takeda Agreement [Member]
Inflow From Issuance Of Intangible Asset
Inflow From Issuance Of Intangible Asset				$ 30,000	$ 50,000
Percentage of share of operating profit or loss					70.00%
Collaborative arrangement additional consideration receivable				$ 15,000		$ 15,000
Takeda Pharmaceutical Company Limited [Member] \| Takeda Agreement [Member] \| Clinical and Regulatory Milestones On Development Program [Member]
Inflow From Issuance Of Intangible Asset
Milestone payment receivable					$ 200,000		200,000
Takeda Pharmaceutical Company Limited [Member] \| Takeda Agreement [Member] \| Sales Milestones On Development Program [Member]
Inflow From Issuance Of Intangible Asset
Milestone payment receivable					150,000		150,000
Takeda Pharmaceutical Company Limited [Member] \| Takeda Agreement [Member] \| Clinical and Regulatory Milestones on Licensed Discovery Product [Member]
Inflow From Issuance Of Intangible Asset
Milestone payment receivable					240,000		240,000
Takeda Pharmaceutical Company Limited [Member] \| Takeda Agreement [Member] \| Sales Milestones on Licensed Discovery Product [Member]
Inflow From Issuance Of Intangible Asset
Milestone payment receivable					$ 300,000		$ 300,000
H. Lee Moffitt Cancer Center [Member] \| Alliance Agreement [Member]
Inflow From Issuance Of Intangible Asset
Research development and manufacturing services aggregate annual amount			$ 3,500
Collaborative arrangement aggregate consideration payable			$ 17,500
Number of new stock issued during the period		91,721
H. Lee Moffitt Cancer Center [Member] \| Alliance Agreement [Member] \| Performance Shares [Member]
Inflow From Issuance Of Intangible Asset
Number of new stock issued during the period			91,721
Number of non-vested equity-based payment instruments			366,884
H. Lee Moffitt Cancer Center [Member] \| Alliance Agreement [Member] \| Sales Based Milestones [Member]
Inflow From Issuance Of Intangible Asset
Other commitment			$ 50,000

Income Taxes - Additional Information (Detail) - USD ($)			12 Months Ended
	Feb. 09, 2022	Jun. 29, 2020	Dec. 31, 2023	Dec. 31, 2022
Operating Loss Carryforwards [Line Items]
Uncertain tax benefits			$ 2,197,000	$ 857,000
Interest or penalties related to the uncertain tax positions			0
Loss before income taxes			(55,486,000)	$ (30,693,000)
California Franchise Tax Board [Member] \| Maximum [Member]
Operating Loss Carryforwards [Line Items]
Loss before income taxes		$ 1,000,000
California Franchise Tax Board [Member] \| Tax Year 2022 [Member]
Operating Loss Carryforwards [Line Items]
Removal of amount of tax that can be offset by business credits	$ 5,000,000
California Franchise Tax Board [Member] \| Tax Years 2020 and 2021 and 2022 [Member]
Operating Loss Carryforwards [Line Items]
Amount of tax that can be offset by business credits		$ 5,000,000
Research and Development [Member]
Operating Loss Carryforwards [Line Items]
Uncertain tax benefits			2,200,000
Reduction of the deferred tax asset related credit carryforward			1,900,000
Research and Development [Member] \| California Franchise Tax Board [Member]
Operating Loss Carryforwards [Line Items]
Tax credits			2,300,000
Research and Development [Member] \| Canada Revenue Agency [Member]
Operating Loss Carryforwards [Line Items]
Non-refundable investment tax credits			21,900,000
Investment [Member] \| Canada Revenue Agency [Member]
Operating Loss Carryforwards [Line Items]
Tax credits			$ 500,000
Tax credits, expiration year			2038
Non-refundable investment tax credits			$ 7,600,000
Non-Capital Losses [Member] \| Canada Revenue Agency [Member]
Operating Loss Carryforwards [Line Items]
Tax credits			0
Federal [Member]
Operating Loss Carryforwards [Line Items]
Net operating loss, or NOL, carryforwards			$ 39,700,000
Operating Loss Carryforwards, Limitations on Use			The Company’s U.S. federal NOL carryforwards can be carried forward indefinitely, but use of such carryforwards is limited to 80% of taxable income.
Federal [Member] \| Research and Development [Member]
Operating Loss Carryforwards [Line Items]
Tax credits			$ 5,000,000
Tax credits, expiration year			2039
State [Member]
Operating Loss Carryforwards [Line Items]
Net operating loss, or NOL, carryforwards			$ 9,300,000
Net operating loss carryforwards, expiration year			2038

Equity Based Compensation - Schedule of Fair Value Assumption of Stock Option Activity (Detail) - $ / shares	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Schedule Of Share Based Payment Award Stock Options Valuation Assumptions [Line Items]
Risk-free interest rate, Minimum	3.90%	1.70%
Risk-free interest rate, Maximum	4.80%	3.60%
Dividend yield	0.00%	0.00%
Volatility, Minimum	85.80%	86.30%
Volatility, Maximum	88.20%	87.20%
Weighted-average exercise price of stock options granted	$ 5.44	$ 11.02
Minimum [Member]
Schedule Of Share Based Payment Award Stock Options Valuation Assumptions [Line Items]
Expected term (in years)	5 years 9 months 18 days	5 years 8 months 12 days
Maximum [Member]
Schedule Of Share Based Payment Award Stock Options Valuation Assumptions [Line Items]
Expected term (in years)	6 years 2 months 12 days	6 years

Income Taxes - Schedule of Components of the Company's Deferred Income Tax Assets (Detail) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Deferred tax assets:
Credits	$ 10,874	$ 7,960
Accruals	125	108
Stock compensation	898	1,111
State taxes	1	33
Right-of-use lease liability	680	1,319
Property and equipment		144
Intangibles	20,726	16,858
Tax losses	14,783	7,253
Deferred revenue		5,290
Total deferred tax assets	48,087	40,076
Deferred tax liability:
Right-of-use lease asset	(588)	(1,174)
Property and equipment	(734)	(1,665)
Unrealized gains/losses	(3)
Total deferred tax liability	(1,325)	(2,839)
Valuation allowance	(46,762)	(37,237)
Net deferred tax assets	$ 0	$ 0

Accrued Expenses and Other Current Liabilities (Tables)

12 Months Ended

Dec. 31, 2023

Accrued Liabilities and Other Liabilities [Abstract]

Schedule of Accrued Liabilities and Other Current Liabilities

Accrued expenses and other current liabilities consist of the following (in thousands):


	December 31,		December 31,
	2023		2022
Research and development expense	$	5,675	$	6,688
Professional and consulting expense		641		1,170
Compensation		3,593		2,366
Contingent consideration, current		—		3,791
Other current liabilities		—		272
Total accrued expenses and other current liabilities	$	9,909	$	14,287

Nature of the Business and Basis of Presentation

12 Months Ended

Dec. 31, 2023

Business Description And Basis Of Presentation [Abstract]

Nature of the Business and Basis of Presentation

1. Nature of the Business and Basis of Presentation

Organization

Turnstone Biologics Corp. (the “Company” or “Turnstone”) is a clinical stage biotechnology company focused on developing new medicines to treat and cure patients with solid tumors. Turnstone is pioneering a differentiated approach to tumor infiltrating lymphocytes (“TILs”), a clinically validated technology for treating solid tumors. The Company is developing next generation TIL therapies by selecting the most potent and tumor reactive T cells (“Selected TILs”). The Company has initiated two Phase 1 clinical trials for its lead Selected TIL product candidate, TIDAL-01, for the treatment of breast cancer, colorectal cancer, uveal melanoma and other non-cutaneous and cutaneous melanomas. The Company’s headquarters are located in San Diego, California.

Reverse Stock Split

On July 14, 2023, the Company effected a 1-for-7.9872 reverse stock split (“Reverse Split”) of its issued and outstanding shares of common stock and redeemable convertible preferred stock. All share and per share amounts included in the accompanying consolidated financial statements and related notes have been retroactively adjusted, where applicable, to reflect the Reverse Split, including reclassifying an amount equal to the reduction in par value of common stock to additional paid-in capital. Shares of common stock, underlying outstanding stock options, and restricted stock were proportionately reduced and the respective exercise prices, if applicable, were proportionately increased in accordance with the terms of the appropriate securities agreements. Stockholders entitled to fractional shares as a result of the Reverse Split received a cash payment in lieu of receiving fractional shares.

Initial Public Offering

On July 25, 2023, the Company completed its initial public offering ("IPO") pursuant to which it issued and sold an aggregate of 6,666,667 shares of common stock at a price to the public of $12.00 per share. Aggregate net proceeds to the Company were $68.7 million after deducting underwriting discounts and commissions of $5.6 million and other offering expenses of $5.7 million. On August 15, 2023, the underwriters exercised their option to purchase an additional 651,608 shares of common stock at $12.00 per share. Aggregate net proceeds to the Company were $7.3 million after deducting underwriting discounts and commissions of $0.5 million. Upon the closing of the IPO, all outstanding shares of redeemable convertible preferred stock automatically converted into shares of common stock. Subsequent to the closing of the IPO, there were no shares of redeemable convertible preferred stock outstanding.

In connection with the closing of the IPO, the Company filed its Amended and Restated Certificate of Incorporation which provides that the authorized capital stock of the Company is 500,000,000 shares consisting of 490,000,000 shares of common stock and 10,000,000 shares of undesignated preferred stock, both with a par value of $0.001 per share.

Sources of Liquidity

Since its inception, the Company has devoted substantially all of its efforts and financial resources to organizing and staffing the Company, business planning, raising capital, discovering product candidates and securing related intellectual property rights, and conducting research and development activities for its Selected TIL programs and product candidates. The Company does not have any products approved for sale, has not generated any revenue from product sales and has incurred overall net losses since commencement of the Company’s operations, including a net loss of $55.2 million and $30.8 million for the twelve months ended December 31, 2023 and 2022, respectively. The Company has financed its operations through the issuance and sale of shares of the Company’s redeemable convertible preferred stock, from collaboration revenue received pursuant to certain collaboration agreements, and most recently, with proceeds from the IPO completed on July 25, 2023 and the exercise of the underwriters option to purchase additional shares on August 15, 2023. As of December 31, 2023, the

Company had an accumulated deficit of $176.8 million. The Company expects to continue to generate significant operating losses for the foreseeable future.

The Company has evaluated and concluded there are no conditions or events, considered in the aggregate, that raise substantial doubt about its ability to continue as a going concern for a period of one year following the date these consolidated financial statements are issued and believes its existing cash and cash equivalents and short-term investments as of December 31, 2023 of $94.8 million will be sufficient to fund its operating expenses and capital expenditure requirements for at least 12 months from the date these consolidated financial statements are filed with the Securities and Exchange Commission (“SEC”).

The Company intends to fund future operations and future capital funding needs through equity and/or debt financings, as well as possible asset sales, licensing transactions, and collaborations or strategic partnerships with other companies. The sale of equity or convertible debt could result in additional dilution to stockholders. The incurrence of indebtedness would result in debt service obligations and could result in operating and financial covenants that would restrict the Company’s operations. The Company can provide no assurance that sufficient financing will be available on acceptable terms, if at all. If the Company is not able to secure adequate additional funding it may be forced to make reductions in spending, extend payment terms with suppliers, liquidate assets where possible, and/or suspend or curtail planned programs. Any of these actions could materially harm the Company’s business.

Risks and Uncertainties

The Company is subject to risks and uncertainties common to early-stage companies in the biotechnology industry, including, but not limited to, development by competitors of new technological innovations, dependence on key personnel, protection of proprietary technology, compliance with government regulations and the ability to secure additional capital to fund operations. Product candidates currently under development will require significant additional research and development efforts, including non-clinical and clinical testing and regulatory approval, prior to commercialization. These efforts require significant amounts of additional capital, adequate personnel and infrastructure and extensive compliance and reporting capabilities. Even if the Company’s product development efforts are successful, it is uncertain when, if ever, the Company will realize significant revenue from product sales.

Equity Based Compensation - Schedule of Stock Option Activity (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Schedule Of Share Based Compensation Stock Options Activity [Line Items]
Number of Shares Underlying Outstanding Options, Beginning balance	2,529,982	1,759,275
Options granted	1,028,355	951,543
Options exercised	(29,715)	(61,355)
Options canceled/forfeited	(154,340)	(119,481)
Number of Shares Underlying Outstanding Options, Ending balance	3,374,282	2,529,982	1,759,275
Exercisable	1,792,591
Vested and expected to vest	3,374,282
Weighted- Average Exercise Price Outstanding	$ 8.86	$ 7.26
Options granted	5.44	11.02
Options exercised	3.49	2.55
Options canceled/forfeited	10.29	5.75
Weighted- Average Exercise Price Outstanding	7.66	$ 8.86	$ 7.26
Exercisable	7.93
Vested and expected to vest	$ 7.66
Weighted- Average Remaining Contractual Term (Years) Outstanding	7 years 1 month 6 days	6 years 9 months 18 days	7 years 2 months 12 days
Exercisable	5 years 3 months 18 days
Vested and expected to vest	7 years 1 month 6 days
Aggregate Intrinsic Value Outstanding , Beginning balance	$ 5,886	$ 6,912
Aggregate Intrinsic Value Outstanding , Ending balance	352	$ 5,886	$ 6,912
Exercisable	347
Vested and expected to vest	$ 352

Leases - Schedule of Present Value of Operating Lease Payments (Detail)	Dec. 31, 2023
Schedule of Present Value of Operating Lease Payments [Abstract]
Weighted-average remaining lease term in years	1 year 8 months 12 days
Weighted-average discount rate	5.00%

Leases - Additional Information (Detail) $ in Thousands		1 Months Ended							12 Months Ended
Leases - Additional Information (Detail) $ in Thousands	Dec. 01, 2019	Nov. 30, 2022	Sep. 30, 2022 USD ($)	Mar. 31, 2022	Jun. 30, 2021 SquareFeet	May 31, 2019 SquareFeet	Jan. 31, 2019 SquareFeet	Jul. 31, 2018 SquareFeet	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Nov. 30, 2019 USD ($)	Nov. 01, 2018
Lessee, Lease, Description [Line Items]
Operating lease, impairment loss \| $			$ 500
Lessee, operating lease, liability, to be paid \| $									$ 3,347
Payments for rent \| $									$ 1,600	$ 2,300
Operating lease agreement [Member]
Lessee, Lease, Description [Line Items]
Number of square feet for lease \| SquareFeet						9,423
Lessee, operating lease, term of contract	5 years
Lessee, operating lease, option to extend	one renewal option for a period of five years
Lessee, operating lease, renewal term	5 years
Office space [Member] \| Operating lease agreement [Member]
Lessee, Lease, Description [Line Items]
Number of square feet for lease \| SquareFeet								6,500
Lessee, operating lease, term of contract												7 years 3 months
Laboratory space [Member] \| Operating lease agreement [Member]
Lessee, Lease, Description [Line Items]
Number of square feet for lease \| SquareFeet							6,000
Lessee, operating lease, term of contract											3 years
Lessee, operating lease, liability, to be paid \| $											$ 100
Lessee, operating lease, option to extend		the lease was extended for a one year period.
Lessee, operating lease, renewal term		1 year
Office and laboratory space [Member] \| Operating lease agreement [Member]
Lessee, Lease, Description [Line Items]
Number of square feet for lease \| SquareFeet					19,474
Lessee, operating lease, term of contract				38 months
Lessee, operating lease, option to extend				one renewal option for a period of three years and commenced in March 2022
Lessee, operating lease, renewal term				3 years

Accrued Expenses and Other Current Liabilities

12 Months Ended

Dec. 31, 2023

Accrued Liabilities and Other Liabilities [Abstract]

Accrued Expenses and Other Current Liabilities

5. Accrued Expenses and Other Current Liabilities

Accrued expenses and other current liabilities consist of the following (in thousands):


	December 31,		December 31,
	2023		2022
Research and development expense	$	5,675	$	6,688
Professional and consulting expense		641		1,170
Compensation		3,593		2,366
Contingent consideration, current		—		3,791
Other current liabilities		—		272
Total accrued expenses and other current liabilities	$	9,909	$	14,287

Fair Value of Financial Assets and Liabilities - Schedule of company's contingent consideration measured at fair value level 3 (Detail) - Contingent consideration [Member] $ in Thousands	12 Months Ended
	Dec. 31, 2023 USD ($)
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning balance	$ 5,994
Changes in the fair value of contingent consideration	109
Cash payment of Myst milestone	(2,375)
Equity issuance related to milestone achievement	(2,812)
Ending balance	$ 916

Summary of Significant Accounting Policies - Additional Information (Detail)		12 Months Ended
	Jul. 25, 2023	Dec. 31, 2023 USD ($) Segment	Dec. 31, 2022 USD ($)
Significant Accounting Policies [Line Items]
Number of operating segment \| Segment		1
Restricted cash		$ 100,000	$ 400,000
Impairment losses		$ 1,582,000	$ 497,000
Impairment, Long-Lived Asset, Held-for-Use, Statement of Income or Comprehensive Income [Extensible Enumeration]		Operating Expenses	Operating Expenses
Stock split, conversion ratio	0.1252
Description of the reverse stock split arrangement	1-for-7.9872
Accrued interest and penalties related to unrecognized tax benefits		$ 0
Deferred offering costs		$ 0	$ 1,900,000
Change in Accounting Principle, Accounting Standards Update, Adopted [true false]		true
Change in Accounting Principle, Accounting Standards Update, Adoption Date		Jan. 01, 2023
Change in Accounting Principle, Accounting Standards Update, Immaterial Effect [true false]		true
Change in Accounting Principle, Accounting Standards Update, Transition Option Elected [Extensible Enumeration]		us-gaap:AccountingStandardsUpdate201613Member
Laboratory, Office Equipment and Furniture [Member]
Significant Accounting Policies [Line Items]
Property and equipment, useful life		5 years
Leasehold Improvements [Member]
Significant Accounting Policies [Line Items]
Property, Plant, and Equipment, Useful Life, Term, Description [Extensible Enumeration]		us-gaap:UsefulLifeShorterOfTermOfLeaseOrAssetUtilityMember
Minimum [Member] \| Computer Equipment and Software [Member]
Significant Accounting Policies [Line Items]
Property and equipment, useful life		2 years
Maximum [Member] \| Computer Equipment and Software [Member]
Significant Accounting Policies [Line Items]
Property and equipment, useful life		3 years
Credit Concentration Risk [Member] \| Accounts Receivable [Member]
Significant Accounting Policies [Line Items]
Accounts receivable		$ 200,000	8,700,000
Allowance for doubtful accounts receivable		$ 0	0
Concentration risk, percentage		100.00%
Accounts receivable write-off		$ 0	$ 0

Equity Based Compensation - Summary of RSU Activity (Details) - RSUs [Member]	12 Months Ended
	Dec. 31, 2023 $ / shares shares
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
RSUs granted \| shares	102,945
Number of Outstanding RSUs, Ending balance \| shares	102,945
RSUs granted \| $ / shares	$ 2.71
Weighted-Average Grant Date Fair Value, Ending balance \| $ / shares	$ 2.71

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
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-Name Accounting Standards Codification
-Section 35
-Paragraph 1D
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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Reference 4: http://www.xbrl.org/2003/role/disclosureRef
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Reference 9: http://www.xbrl.org/2003/role/disclosureRef
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+ Details

Fair Value of Financial Assets and Liabilities - Schedule of unobservable input of contingent consideration valuation (Detail) - Contingent consideration [Member] $ in Thousands	Dec. 31, 2023 USD ($) yr	Dec. 31, 2022 USD ($) yr
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair value of financial liabilities \| $	$ 916	$ 5,994
Measurement input likelihood of occurrence [Member] \| Valuation technique discounted cash flow [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Contingent consideration input range	10
Measurement input likelihood of occurrence [Member] \| Valuation technique discounted cash flow [Member] \| Minimum [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Contingent consideration input range		20
Measurement input likelihood of occurrence [Member] \| Valuation technique discounted cash flow [Member] \| Maximum [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Contingent consideration input range		100
Measurement input discount rate [Member] \| Valuation technique discounted cash flow [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Contingent consideration input range	25	22
Measurement input expected term [Member] \| Valuation technique discounted cash flow [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Contingent consideration input range	3.5
Measurement input expected term [Member] \| Valuation technique discounted cash flow [Member] \| Minimum [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Contingent consideration input range		0.25
Measurement input expected term [Member] \| Valuation technique discounted cash flow [Member] \| Maximum [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Contingent consideration input range		2.75

Leases

12 Months Ended

Dec. 31, 2023

Leases [Abstract]

Leases

11. Leases

Operating Leases

The Company leases laboratory and office space for its corporate headquarters located in San Diego, California as well as in New York, New York and Ontario, Canada. Operating lease liabilities are recognized based on the present value of the future minimum lease payments over the lease term. In calculating the present value of the lease payments, the Company has elected to utilize its incremental borrowing rate based on the original lease term and not the remaining lease term. The Company determines if an arrangement is a lease by considering whether there is an identified asset, and the contract conveys the right to control its use. Leases with an initial term of 12 months or less are not recorded on the balance sheet. The Company’s lease terms may include options to extend or terminate a lease. If the lease includes non-lease components (i.e., common area maintenance) that are paid separately from rent based on actual costs incurred and therefore are not included in the right-of-use asset and lease liability but are reflected as an expense in the period incurred.

In July 2018, the Company entered into a lease agreement for approximately 6,500 square feet of office space in New York, New York. The term of the lease is seven years and three months, starting November 1, 2018. The lease requires the Company to share in prorated expenses and property taxes based upon actual amounts incurred. The lease contains escalating rent clauses which require higher rent payments in future years. In September 2022, the Company made the decision to sublease this space and executed a sublease in November 2022 for the remaining term of the lease. Since the Company is still responsible for making the lease payments, there was no impact to the operating lease liability from the sublease. However, since the sublease payment does not cover the entire lease payment, the carrying value of the operating right of use asset was analyzed and determined to be impaired resulting in a $0.5 million reduction in the operating right of use asset in September 2022.

In January 2019, the Company executed an agreement to lease approximately 6,000 square feet of laboratory space at Carleton University in Ontario, Canada. The initial term of the lease is three years and started in November 2019 at a rate of approximately $0.1 million per year. In November 2022, the lease was extended for a one year period. In August 2023, the Company terminated the lease.

In May 2019, the Company entered into a noncancelable operating lease for approximately 9,423 square feet located at 12 York Street, Ontario, CA. The term of the lease is five years, starting December 1, 2019, and includes one renewal option for a period of five years. The lease requires the Company to share in prorated expenses and property taxes based upon actual amounts incurred. The lease contains escalating rent clauses which require higher rent payments in future years.

In June 2021, the Company entered into a lease agreement for approximately 19,474 square feet of office and laboratory space in San Diego, California. The initial term of the lease is 38 months with one renewal option for a period of three years and commenced in March 2022. The lease requires the Company to share in prorated expenses and property taxes based upon actual amounts incurred. The lease contains escalating rent clauses which require higher rent payments in future years.

The Company recorded rent expense of $1.6 million and $2.3 million for the twelve months ended December 31, 2023 and 2022, respectively. The table below summarizes the Company’s total lease costs included in its consolidated financial statements, as well as other required quantitative disclosures (in thousands).


	Year Ended December 31,
	2023			2022
Operating lease cost	$	2,074		$	1,956
Short-term lease costs		4			263
Variable leases costs		5			52
Sublease income		(477	)		(21	)
Total lease cost	$	1,606		$	2,250

The present value assumptions used in calculating the present value of the lease payments were as follows:


	Year ended
	December 31, 2023
Weighted-average remaining lease term in years		1.7
Weighted-average discount rate	5.0%

The minimum aggregate future operating lease commitments at December 31, 2023 are as follows (in thousands):


	Minimum Lease Payments
2024		2,133
2025		1,110
2026		104
2027		—
2028		—
Total undiscounted lease payments	$	3,347
Less: imputed interest		(133	)
Total operating lease liability		3,214
Less: current portion of operating lease liability		(2,025	)
Operating lease liability, noncurrent	$	1,189

Net Loss per Share - Schedule of Dilutive Securities Excluded From Computation of Diluted Net Loss Per Share (Detail) - shares	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	3,567,967	15,205,341
Redeemable Convertible Preferred Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount		12,493,879
Restricted Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	90,740	181,480
Unvested RSUs
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	102,945
Options to purchase common stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	3,374,282	2,529,982

Consolidated Statements of Redeemable Convertible Preferred Stock and Stockholders' Equity (Deficit) - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Accumulated Deficit [Member]	Series A redeemable convertible preferred stock [Member] Preferred Stock [Member]	Series B-1 Redeemable Convertible Preferred Stock [Member]	Series B-1 Redeemable Convertible Preferred Stock [Member] Preferred Stock [Member]	Series B-2 Redeemable Convertible Preferred Stock [Member]	Series B-2 Redeemable Convertible Preferred Stock [Member] Preferred Stock [Member]	Series C redeemable convertible preferred stock [Member] Preferred Stock [Member]	Series D redeemable convertible preferred stock [Member] Preferred Stock [Member]
Beginning balance (in shares) at Dec. 31, 2021						11,250,000		16,285,156		25,065,538	17,905,288	29,285,356
Beginning balance at Dec. 31, 2021						$ 8,582		$ 12,611		$ 28,860	$ 42,048	$ 79,653
Beginning balance (in shares) at Dec. 31, 2021		2,550,478
Beginning balance at Dec. 31, 2021	$ (81,851)	$ 3	$ 9,115	$ (245)	$ (90,724)
Accretion of redeemable convertible preferred stock issuance costs						$ 61					$ 52	$ 77
Accretion of redeemable convertible preferred stock issuance costs	(190)		(190)
Issuance of common stock upon Myst milestone achievement (in shares)		212,203
Issuance of common stock upon Myst milestone achievement	5,000		5,000
Moffitt performance based common stock award (in shares)		91,721
Moffitt performance based common stock award	$ 2,051		2,051
Exercise of stock options (in shares)	61,355	61,355
Exercise of stock options	$ 157		157
Stock-based compensation expense	4,368		4,368
Unrealized gain (loss) on available-for-sale debt securities	(168)			(168)
Net loss	$ (30,834)				(30,834)
Ending balance (in shares) at Dec. 31, 2022						11,250,000	16,285,156	16,285,156	25,065,538	25,065,538	17,905,288	29,285,356
Ending balance at Dec. 31, 2022						$ 8,643		$ 12,611		$ 28,860	$ 42,100	$ 79,730
Ending balance (in shares) at Dec. 31, 2022	2,915,757	2,915,757
Ending balance at Dec. 31, 2022	$ (101,467)	$ 3	20,501	(413)	(121,558)
Proceeds from IPO, net of issuance costs (in shares)		7,318,275
Proceeds from IPO, net of issuance costs	75,963	$ 7	75,956
Conversion of redeemable convertible preferred stock to common stock due to the IPO (in shares)						(11,250,000)		(16,285,156)		(25,065,538)	(17,905,288)	(29,285,356)
Conversion of redeemable convertible preferred stock to common stock due to the IPO						$ (8,643)		$ (12,611)		$ (28,860)	$ (42,100)	$ (79,769)
Conversion of redeemable convertible preferred stock to common stock due to the IPO (in shares)		12,493,879
Conversion of redeemable convertible preferred stock to common stock due to the IPO	171,983	$ 13	171,970
Accretion of redeemable convertible preferred stock issuance costs												$ 39
Accretion of redeemable convertible preferred stock issuance costs	(39)		(39)
Issuance of common stock upon Myst milestone achievement (in shares)		249,992
Issuance of common stock upon Myst milestone achievement	$ 2,812		2,812
Moffitt performance based common stock award (in shares)		91,721
Exercise of stock options (in shares)	29,715	29,711
Exercise of stock options	$ 105		105
Stock-based compensation expense	4,216		4,216
Unrealized gain (loss) on available-for-sale debt securities	294			294
Net loss	$ (55,200)				(55,200)
Ending balance (in shares) at Dec. 31, 2023							0		0
Ending balance (in shares) at Dec. 31, 2023	23,099,335	23,099,335
Ending balance at Dec. 31, 2023	$ 98,667	$ 23	$ 275,521	$ (119)	$ (176,758)

Leases - Schedule of Minimum Aggregate Future Operating Lease Commitments (Detail) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Lessee, Operating Lease, Liability, to be Paid, Fiscal Year Maturity [Abstract]
2024	$ 2,133
2025	1,110
2026	104
2027	0
2028	0
Total undiscounted lease payments	3,347
Less: imputed interest	(133)
Total operating lease liability	3,214
Less: current portion of operating lease liability	(2,025)	$ (1,961)
Operating lease liability, noncurrent	$ 1,189	$ 3,205

Asset Acquisition - Additional Information (Detail) - USD ($) $ in Thousands					1 Months Ended		12 Months Ended
	Sep. 11, 2023	Jun. 14, 2022	Jun. 08, 2022	Dec. 15, 2020	Jan. 31, 2023	Jul. 31, 2022	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2020	Sep. 30, 2023	Jul. 25, 2023	Jan. 10, 2023	Jul. 28, 2022	Jul. 25, 2022	May 31, 2022
Asset Acquisition [Line Items]
Payment for contingent consideration liability							$ 898	$ 2,813
Third Milestone Payment [Member]
Asset Acquisition [Line Items]
Contingent consideration payable				$ 20,000
Langer [Member] \| Initial Milestone Payment [Member]
Asset Acquisition [Line Items]
Contingent consideration payable by shares										$ 2,800
Stock issued during the period for milestone payments shares	249,992
Langer [Member] \| Second Milestone Payment [Member]
Asset Acquisition [Line Items]
Contingent consideration payable														$ 9,400
Contingent consideration payable by shares						$ 5,000
Contingent consideration payable by cash												$ 2,200	$ 2,200
Stock issued during the period for milestone payments shares			212,203
Stock issued during the period for milestone payments value			$ 5,000
Payment for contingent consideration liability					$ 2,200	2,200
Myst Holders [Member] \| Initial Milestone Payment [Member]
Asset Acquisition [Line Items]
Contingent consideration payable	$ 3,000
Myst Holders [Member] \| Second Milestone Payment [Member]
Asset Acquisition [Line Items]
Contingent consideration payable														10,000	$ 10,000
Contingent consideration payable by shares															5,000
Contingent consideration payable by cash															$ 5,000
Payment for contingent consideration liability						2,800
Remaining Myst Holders [Member] \| Initial Milestone Payment [Member]
Asset Acquisition [Line Items]
Contingent consideration payable by cash										$ 200
Remaining Myst Holders [Member] \| Second Milestone Payment [Member]
Asset Acquisition [Line Items]
Contingent consideration payable by cash														$ 600
Payment for contingent consideration liability						$ 600
Myst Merger Agreement [Member]
Asset Acquisition [Line Items]
Payments to acquire productive assets		$ 1,000		9,000
Research and development asset acquired other than through business combination, write-off									$ 19,400
Research and Development Asset Acquired Other than through Business Combination, Writeoff, Statement of Income or Comprehensive Income [Extensible Enumeration]									Nonoperating Income (Expense)
Asset acquisition contingent consideration arrangements change in amount of contingent consideration, liability							$ 900	$ 7,000
Myst Merger Agreement [Member] \| Initial Milestone Payment [Member]
Asset Acquisition [Line Items]
Contingent consideration, liability											$ 3,000
Myst Merger Agreement [Member] \| Second Milestone Payment [Member]
Asset Acquisition [Line Items]
Contingent consideration payable				$ 10,000
Myst Merger Agreement [Member] \| Langer [Member]
Asset Acquisition [Line Items]
Asset acquisition, consideration transferred, equity interest issued and issuable shares		725,920
Asset acquisition consideration transferred equity interest issued shares		362,960
Asset acquisition consideration transferred equity interest issuable shares		362,960
Myst Merger Agreement [Member] \| Langer [Member] \| Restricted Stock [Member]
Asset Acquisition [Line Items]
Percentage of vesting of award under share-based payment arrangement		25.00%
Number of equity-based payment instruments vested during the period							272,220
Number of non-vested equity-based payment instruments							90,740

Nature of the Business and Basis of Presentation - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands			12 Months Ended
	Aug. 15, 2023	Jul. 25, 2023	Dec. 31, 2023	Dec. 31, 2022
Business Description And Basis Of Presentation [Line Items]
Description of the reverse stock split arrangement		1-for-7.9872
Number of new stock issued during the period	651,608
Shares issued, price per share	$ 12
Cash received on stock transaction after deduction of issuance costs	$ 7,300
Underwriting discounts and commissions	$ 500
Shares authorized		500,000,000
Common stock, shares authorized		490,000,000	490,000,000	147,892,358
Preferred stock, shares authorized		10,000,000	10,000,000	0
Common stock par value		$ 0.001	$ 0.001	$ 0.001
Preferred stock par value		$ 0.001	$ 0.001	$ 0.001
Net income (loss)			$ 55,200	$ 30,834
Accumulated deficit			176,758	$ 121,558
Cash, cash equivalents, and short-term investments			$ 94,800
IPO [Member]
Business Description And Basis Of Presentation [Line Items]
Number of new stock issued during the period		6,666,667
Shares issued, price per share		$ 12
Cash received on stock transaction after deduction of issuance costs		$ 68,700
Underwriting discounts and commissions		5,600
Other offering expenses		$ 5,700

Leases (Tables)

12 Months Ended

Dec. 31, 2023

Leases [Abstract]

Schedule of information about lease costs

The table below summarizes the Company’s total lease costs included in its consolidated financial statements, as well as other required quantitative disclosures (in thousands).


	Year Ended December 31,
	2023			2022
Operating lease cost	$	2,074		$	1,956
Short-term lease costs		4			263
Variable leases costs		5			52
Sublease income		(477	)		(21	)
Total lease cost	$	1,606		$	2,250

Schedule of present value of operating lease payments

The present value assumptions used in calculating the present value of the lease payments were as follows:


	Year ended
	December 31, 2023
Weighted-average remaining lease term in years		1.7
Weighted-average discount rate	5.0%

Schedule of minimum aggregate future operating lease commitments

The minimum aggregate future operating lease commitments at December 31, 2023 are as follows (in thousands):


	Minimum Lease Payments
2024		2,133
2025		1,110
2026		104
2027		—
2028		—
Total undiscounted lease payments	$	3,347
Less: imputed interest		(133	)
Total operating lease liability		3,214
Less: current portion of operating lease liability		(2,025	)
Operating lease liability, noncurrent	$	1,189

Summary of Significant Accounting Policies

12 Months Ended

Dec. 31, 2023

Accounting Policies [Abstract]

Summary of Significant Accounting Policies

2. Summary of Significant Accounting Policies

Basis of Presentation of Consolidated Financial Information

The accompanying consolidated financial statements of the Company have been prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”) and pursuant to the rules and regulations of the SEC. Certain prior period amounts reported in the Company’s consolidated financial statements and accompanying notes have been reclassified to conform to the current period presentation. Any reference in these notes to applicable guidance is meant to refer to the authoritative accounting principles generally accepted in the United States as found in the Accounting Standard Codification (“ASC”) and Accounting Standards Update (“ASU”) of the Financial Accounting Standards Board (“FASB”).

Principles of Consolidation

The accompanying consolidated financial statements include the accounts of the Company and its wholly owned subsidiaries. All intercompany balances and transactions have been eliminated in consolidation.

Use of Estimates

The preparation of these consolidated financial statements in accordance with GAAP requires management to make estimates and assumptions that affect the amounts reported in the consolidated financial statements and accompanying notes. On an ongoing basis, management evaluates its estimates, including those related to accrued expenses, contingent liabilities, impairment of long-lived assets, revenue recognition, the valuation of equity-based compensation, common stock, restricted common stock, and income taxes. The Company bases its estimates on

various assumptions that the Company believes to be reasonable under the circumstances. Actual results could differ from those estimates.

Segment Reporting

The Company has determined that it operates and manages one operating segment, which is the business of developing and commercializing therapeutics. The Company’s chief operating decision maker, its chief executive officer, reviews financial information on an aggregate basis for the purpose of allocating resources.

Cash and Cash Equivalents

Cash and cash equivalents consist of checking, money market and highly liquid investments that are readily convertible to cash and that have an original maturity of three months or less from date of purchase. The carrying amounts approximate fair value due to the short maturities of these instruments.

Restricted Cash and Investments

Restricted cash consists of certificate of deposit accounts that are pledged as collateral for the Company’s San Diego facility lease as of December 31, 2023 and the San Diego and New York facility leases as of December 31, 2022. Restricted cash was approximately $0.1 million and $0.4 million as of December 31, 2023 and 2022, respectively.

The Company invests its excess cash in investment grade, short-term, fixed income securities and recognizes purchased securities on the settlement date. All investments have been classified as “available-for-sale” in the consolidated balance sheets and are carried at estimated fair value based upon quoted market prices or pricing models for similar securities. Management determines the appropriate classification of its investments at the time of purchase and re-evaluates such designation as of each balance sheet date.

The Company assesses its available-for-sale securities under the available-for-sale security impairment model in ASC Topic 326, Financial Instruments—Credit Losses (“ASC 326”) as of each reporting date in order to determine if a portion of any decline in fair value below carrying value is the result of a credit loss. The Company records credit losses in the consolidated statements of operations and comprehensive loss as credit loss expense, which is limited to the difference between the fair value and the amortized cost of the security. To date, the Company has not recorded any credit losses on its available-for-sale securities. Declines in fair value below carrying value attributable to non-credit related factors are recorded as accumulated other comprehensive loss, which is a separate component of stockholders’ equity (deficit).

Realized gains and losses are reported in other income (expense), net. Interest on short-term investments is included in other income (expense), net. The Company’s investments are classified as current assets which reflects management’s intention to use the proceeds from sales of these securities to fund its operations, as necessary.

Concentration of Credit Risk

Financial instruments that potentially subject the Company to concentrations of credit risk consist principally of cash and cash equivalents, investments and restricted cash. The Company’s investment policy restricts cash investments to high credit quality, investment grade investments. The Company’s investment policy provides guidelines and limits regarding investment type, concentration, credit quality, and maturity aimed at maintaining sufficient liquidity to satisfy operating and working capital requirements along with strategic initiatives, preserving capital, and minimizing risk of capital loss while generating returns on its investments. The Company is exposed to credit risk in the event of default by the issuer or the institutions holding the cash and cash equivalents to the extent of the amounts recorded on the balance sheets.

The Company records accounts receivable amounts invoiced to a collaborator, for which the Company has an unconditional right to consideration. For amounts to which the Company has an unconditional right to consideration but has not yet invoiced the collaborator, the Company records unbilled accounts receivable. The Company

estimates an allowance for credit losses based on the creditworthiness of its collaborator, current economic conditions and future economic conditions, as may be applicable. If a receivable is deemed to be uncollectible, the balance is charged against the allowance. As of December 31, 2023 and December 31, 2022, the Company had an accounts receivable balance of $0.2 million and $8.7 million, respectively of which Takeda accounted for 100%, and no allowance was recorded. Accounts receivable and unbilled accounts receivable are presented in accounts receivable, net on the consolidated balance sheets. During the twelve months ended December 31, 2023 and 2022, the Company did not recognize any charges for write-offs of accounts receivable.

The Company has no off-balance sheet risk, such as foreign exchange contracts, option contracts or other foreign-hedging arrangements.

Fair Value Measurements

The Company applies fair value accounting for all financial assets and liabilities and non-financial assets and liabilities that are recognized or disclosed at fair value in the consolidated financial statements on a recurring basis. Fair value is defined as the exchange price that would be received for an asset or an exit price that would be paid to transfer a liability in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. The fair value hierarchy requires that an entity maximize the use of observable inputs when estimating fair value. The fair value hierarchy includes the following three-level classification which is based on the market observability of the inputs used for estimating the fair value of the assets or liabilities being measured:

Level 1 – Quoted market prices in active markets for identical assets or liabilities.

Level 2 – Observable inputs other than quoted prices in active markets for identical assets and liabilities, quoted prices for identical or similar assets or liabilities in inactive markets, or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities.

Level 3 – Inputs that are generally unobservable and typically reflect management’s estimate of assumptions that a market participant would use in pricing the asset or liability.

Fair value accounting is applied for all financial assets and liabilities and non-financial assets and liabilities that are recognized at fair value in the consolidated financial statements on a recurring basis (at least annually). To the extent the valuation is based on models or inputs that are less observable or unobservable in the market, the determination of fair values requires more judgment. Accordingly, the degree of judgment exercised by the Company in determining fair value is greatest for instruments categorized as Level 3. A financial instrument’s level within the fair value hierarchy is based on the lowest level of any input that is significant to the fair value measurement.

Investment Tax Credits

The Company claims Scientific Research and Experimental Development (“SR&ED”) deductions and related investment tax credits for income tax purposes based upon management’s interpretation of the applicable legislation in the Income Tax Act (Canada). Investment tax credits are subject to Canada Revenue Agency review and assessment of the eligibility of the Company’s research expenditures. These tax credits are applied to reduce the related research and development expenses incurred in the year recognized. Actual investment tax credits received may differ from those estimated and recorded in these consolidated financial statements.

Property and Equipment

Property and equipment are recorded at cost, less accumulated depreciation. Depreciation is computed using the straight-line method over the estimated useful lives of the respective assets, which are two to three years for computer equipment and software, and five years for laboratory, office equipment and furniture. Leasehold improvements are amortized over the shorter of the useful life or the remaining term of the lease.

Revenue Recognition

The Company enters into collaboration arrangements that may include the receipt of payments for up-front license fees, success-based milestone payments, full time equivalent based payments for research services, and royalties on any future sales of commercialized products that result from the collaborations.

Effective January 1, 2017, the Company adopted the provisions of ASC Topic 606, Revenue from Contacts with Customers (“ASC 606”). Under ASC 606, an entity recognizes revenue when its customer obtains control of promised goods or services, in an amount that reflects the consideration which the entity expects to receive in exchange for those goods or services. To determine the appropriate amount of revenue to be recognized for arrangements determined to be within the scope of ASC 606, the Company performs the following five steps: (i) identification of the contract(s) with the customer, (ii) identification of the promised goods or services in the contract and determination of whether the promised goods or services are performance obligations, (iii) measurement of the transaction price, (iv) allocation of the transaction price to the performance obligations, and (v) recognition of revenue when (or as) the Company satisfies each performance obligation. The Company only applies the five-step model to contracts when it is probable that the entity will collect consideration it is entitled to in exchange for the goods or services it transfers to the customer.

The Company accounts for a contract with a customer that is within the scope of ASC 606 when all of the following criteria are met: (i) the arrangement has been approved by the parties and the parties are committed to perform their respective obligations, (ii) each party’s rights regarding the goods or services to be transferred can be identified, (iii) the payment terms for the goods and services to be transferred can be identified, (iv) the arrangement has commercial substance and (v) collection of substantially all of the consideration to which the Company will be entitled in exchange for the goods or services that will be transferred to the customer is probable.

The Company estimates the transaction price based on the amount of consideration the Company expects for transferring the promised goods or services in the contract. The consideration may include both fixed consideration and variable consideration. At the inception of each arrangement that includes variable consideration, the Company evaluates the amount of the potential payments and the likelihood that the payments will be received. The Company utilizes either the most likely amount method or expected value method to estimate the transaction price based on which method better predicts the amount of consideration expected to be received. If it is probable that a significant revenue reversal would not occur, the variable consideration is included in the transaction price.

For arrangements that include development and regulatory milestone payments, the Company evaluates whether the milestones are considered probable of being reached and estimates the amount to be included in the transaction price using the most likely amount method. If it is probable that a significant revenue reversal would not occur, the associated milestone value is included in the transaction price. Milestone payments that are not within the Company’s control or the licensee’s control, such as regulatory approvals, are not considered probable of being achieved until those approvals are received. At the end of each reporting period, the Company re-evaluates the probability of achievement of such milestones and any related constraint, and if necessary, adjusts the estimate of the overall transaction price. Any such adjustments are recorded on a cumulative catch-up basis, which would affect collaboration revenue and net loss in the period of adjustment.

For sales-based royalties, including milestone payments based on the level of sales, the Company determines whether the sole or predominant item to which the royalties relate is a license. When the license is the sole or predominant item to which the sales-based royalty relates, the Company recognizes revenue at the later of: (i) when the related sales occur, or (ii) when the performance obligation to which some or all of the royalty has been allocated has been satisfied (or partially satisfied).

The Company allocates the transaction price based on the estimated standalone selling price. The Company must develop assumptions that require judgment to determine the standalone selling price for each performance obligation identified in the contract. The Company utilizes key assumptions to determine the standalone selling price, which may include other comparable transactions, pricing considered in negotiating the transaction and the estimated costs. Certain variable consideration is allocated specifically to one or more performance obligations in a contract when the terms of the variable consideration related to the satisfaction of the performance obligation and

the resulting amounts allocated to each performance obligation are consistent with the amounts the Company would expect to receive for each performance obligation.

For performance obligations, which consist of licenses and other promises, the Company utilizes judgment to assess the nature of the combined performance obligation in order to determine whether the combined performance obligation is satisfied over time or at a point in time. The Company determines the appropriate method of measuring progress of combined performance obligations satisfied over time for purposes of recognizing revenue determined on a contract by contract basis (See Note 6—Agreements for additional information). The Company evaluates the measure of progress each reporting period and, if necessary, adjusts the measure of performance and related revenue recognition. If the license to the Company’s intellectual property is determined to be distinct from the other performance obligations identified in the arrangement, the Company will recognize revenue from non-refundable, up-front fees allocated to the license when the license is transferred to the customer and the customer is able to use and benefit from the license.

The Company receives payments from customers based on billing schedules established in each contract. Up-front payments and fees are recorded as deferred revenue upon receipt or when due until the Company performs its obligations under these arrangements. Amounts are recorded as accounts receivable when the Company’s right to consideration is unconditional.

Research and Development Expenses

Research and development costs are expensed as incurred. Research and development costs consist of payroll and other personnel-related expenses, materials and supplies, preclinical expenses, manufacturing expenses, contract research and development services, and consulting costs, as well as allocations of facilities and other overhead costs. Costs of certain development activities, such as manufacturing, are recognized based on an evaluation of the progress to completion of specific tasks. Payments for these activities are based on the terms of the individual arrangements, which may differ from the pattern of costs incurred, and are reflected in the consolidated financial statements as prepaid or accrued research and development costs. Non-refundable advance payments for goods or services to be received in the future for use in research and development activities are deferred and capitalized. The capitalized amounts are expensed as the related goods are delivered or the services are performed. Costs associated with collaboration agreements are included in research and development expenses. Assets acquired that are used for research and development and which have no alternative use are expensed to research and development costs.

Preclinical and Clinical Trial Accruals

The Company makes estimates of its accrued expenses as of each balance sheet date in the consolidated financial statements based on the facts and circumstances known at that time. Accrued expenses for preclinical studies and clinical trials are based on estimates of costs incurred and fees that may be associated with services provided by contract research organizations (“CROs”), clinical trial investigational sites and other clinical trial-related activities. Payments under certain contracts with such parties depend on factors such as successful enrollment of patients, site initiation and the completion of clinical trial milestones. In accruing for these services, the Company estimates the time period over which services will be performed and the level of effort to be expended in each period. If possible, the Company obtains information regarding unbilled services directly from these service providers. However, the Company may be required to estimate these services based on other available information. If the Company underestimates or overestimates the activities or fees associated with a study or service at a given point in time, adjustments to research and development expenses may be necessary in future periods. Historically, estimated accrued liabilities have approximated actual expenses incurred. Subsequent changes in estimates may result in a material change in accruals.

Patent Costs

All patent-related costs incurred in connection with filing and prosecuting patent applications are expensed as incurred due to the uncertainty about the recovery of the expenditure. Amounts incurred are classified as general and administrative expenses.

Stock-Based Compensation

The Company accounts for stock-based compensation expense related to stock options and restricted stock units, ("RSUs"), by estimating the fair value on the date of grant. The Company estimates the fair value of stock options granted to employees and non-employees using the Black-Scholes option pricing model. The fair value of RSUs granted to employees is the closing price of the Company’s common stock on the date of grant. The Company recognizes stock-based compensation expense, over the requisite service period, based on the vesting provisions of the individual grants. Generally, the Company issues stock-based awards with only service-based vesting conditions and records the expense for these awards using the straight-line method. The Company accounts for forfeitures when they occur.

The Black-Scholes option pricing model requires inputs based on certain subjective assumptions, including (a) the expected stock price volatility, (b) the expected term of the award, (c) the risk-free interest rate and (d) expected dividend yields. Due to the lack of a public market for the Company’s common stock until July 21, 2023, and lack of company- specific historical and implied volatility data, the Company has based its computation of expected volatility on the average historical volatility of a representative group of public companies with similar characteristics to the Company, including stage of product development and life science industry focus. The historical volatility is calculated based on a period of time commensurate with the expected term. The Company uses the simplified method as prescribed by the U.S. Securities and Exchange Commission Staff Accounting Bulletin No. 107, Share-Based Payment, to calculate the expected term for options granted to employees as it does not have sufficient historical exercise data to provide a reasonable basis upon which to estimate the expected term. The expected term is applied to the stock option grant group as a whole, as the Company does not expect substantially different exercise or post-vesting termination behavior among its employee population. The risk-free interest rate is based on a treasury instrument whose term is consistent with the expected term of the stock options. The expected dividend yield is assumed to be zero as the Company has never paid dividends and has no current plans to pay any dividends on its common stock.

Determination of Fair Value of Common Stock

After the Company's IPO in July 2023, the fair value of common stock is determined using the closing price of the Company's common stock on the Nasdaq Global Select Market. Prior to the IPO, there were significant judgments and estimates inherent in the determination of the fair value of the Company’s common stock. These estimates and assumptions include a number of objective and subjective factors, including, among other things, external market conditions, the prices at which the Company sold shares of its convertible preferred stock, the superior rights and preferences of securities senior to its common stock at the time of, and the likelihood of, achieving a liquidity event, such as an initial public offering or sale of the Company. The approach to estimating the fair market value of common stock is consistent with the methods outlined in the American Institute of Certified Public Accountants’ Accounting and Valuation Guide, Valuation of Privately-Held Company Equity Securities Issued as Compensation (“Practice Aid”).

In valuing the Company’s common stock prior to the IPO, the equity value of the business was determined using the backsolve method, a form of the subject company transaction method, wherein the equity value for a privately held company is derived from a recent transaction in the company’s own securities. The value is then allocated using the hybrid method allocation methodology. For grants made prior to September 30, 2018, in accordance with the Practice Aid, the Company determined the option pricing method (“OPM”), was the most appropriate method for determining the fair value of the Company’s common stock based on its stage of development and other relevant factors. For grants made subsequent to September 30, 2018 but prior to the IPO, the Company used a hybrid method, which is a hybrid between the OPM and the probability-weighted expected return method (“PWERM”). The hybrid method is a combination of the PWERM and OPM. The OPM allocates the overall Company value to the various share classes based on differences in liquidation preferences, participation rights, dividend policy and conversion rights, using a series of call options. The call right is valued using a Black-Scholes option pricing model. The PWERM employs additional information not used in the OPM, including various market approach calculations depending upon the likelihood of various discrete future liquidity scenarios, such as an initial public offering or sale of the Company, as well as the probability of remaining a private company. In a hybrid method, various exit scenarios are analyzed. A discount for lack of marketability of the Company’s common stock was then applied to arrive at an indication of value for the common stock.

Impairment of Long-Lived Assets

The Company reviews long-lived assets for impairment whenever events or changes in circumstances indicate that the carrying amount of such assets may not be recoverable, including evaluating the impact of the overall micro- and macro-economic conditions on the carrying value of its long-lived assets, including property and equipment and operating lease assets. During the twelve months ended December 31, 2023, the Company's stock price and resulting market capitalization experienced a significant, sustained decline. Accordingly, the Company assessed our long-lived assets, including property and equipment and operating lease assets for impairment. Recoverability of these assets is determined by comparing the forecasted undiscounted net cash flows of the operation to which the assets relate to the carrying amount. If the operation is determined to be unable to recover the carrying amount of its assets, then these assets are written down first to fair value Fair value is determined based on discounted cash flows or appraised values, depending on the nature of the assets.

The Company recognized long-lived asset impairment charges of $1.6 million and $0.5 million for the years ended December 31, 2023 and 2022, respectively (See Note 4—Property and Equipment, Net and Note 11—Leases for additional information).

Redeemable Convertible Preferred Stock

The Company records all proceeds from redeemable convertible preferred stock (“Preferred Stock”) net of issuance costs. The Company classifies Preferred Stock outside of stockholders’ equity (deficit) due to certain events that are outside of the Company’s control, including sale or transfer of control of the Company, or redemption upon the election of the required majority of the Preferred Stockholders any time after June 29, 2026, as holders of the Preferred Stock could cause redemption of the shares in these situations. The Company adjusts the carrying values of the Preferred Stock to the ultimate redemption values over the period from issuance to the earliest redemption date. Upon the closing of the IPO, all of the outstanding shares of Preferred Stock automatically converted into shares of common stock in a 1-for-7.9872 reverse stock split.

Income Taxes

The Company accounts for the effect of income taxes in its consolidated financial statements using the asset and liability method in accordance with ASC Topic 740, Income Taxes (“ASC 740”). This process involves estimating actual current tax liabilities together with assessing the impact of carryforward and temporary differences resulting from the differing treatment of items such as depreciation for tax and accounting purposes. These differences result in deferred tax assets and liabilities which are measured using enacted tax rates expected to apply to taxable income in the year in which those temporary differences are expected to reverse.

The Company regularly assesses the likelihood that the deferred income tax assets will be realized. A valuation allowance to reduce the deferred tax assets to the amount that the Company believes is more likely than not to be realized is established based on their judgement of all available positive and negative evidence. The assessment is completed on a taxing jurisdiction basis for each tax-paying component and takes into account a number of types of evidence, including:

• the nature and history of current or cumulative financial reporting income or losses;

• sources of future taxable income;

• the anticipated reversal or expiration dates of deferred tax assets; and

• tax planning strategies.

The Company has established a valuation allowance to offset its gross deferred tax assets as of December 31, 2023 and 2022 due to the uncertainty of realizing future tax benefits primarily related to net operating loss carryforwards and income tax credits in Canada.

The Company applies ASC 740-10 Income Taxes which requires a two-step approach to recording a tax benefit in the consolidated financial statements. The first step requires an evaluation of the tax position to determine whether it is “more likely than not”, based on the technical merits, that it will be sustained on audit. Provided that

the tax position satisfies the recognition step, the Company then measures and records the position at the largest amount of tax benefit that is greater than 50 percent likely of being realized upon settlement of the audit. The Company considers many factors when evaluating and estimating its tax positions and tax benefits, which may require periodic adjustments and may not accurately anticipate actual outcomes. The Company recognizes accrued interest and penalties related to unrecognized tax benefits. There were no accrued interest and penalties as of December 31, 2023.

Net Loss Per Share

Basic net loss per share attributable to common stockholders is calculated by dividing the net loss attributable to common stockholders by the weighted-average number of shares of common stock outstanding during the period.

Diluted net loss per share is computed by giving effect to all potentially dilutive securities outstanding for the period using the treasury stock method or the if-converted method based on the nature of such securities. For periods in which the Company reports net losses, diluted net loss per common share attributable to common stockholders is the same as basic net loss per common share attributable to common stockholders, because potentially dilutive common shares are not assumed to have been issued if their effect is anti-dilutive.

Prior to the Company's IPO, the Company applied the two-class method to compute basic and diluted net loss per share because it had issued redeemable convertible preferred stock that met the definition of participating securities. The two-class method determined net loss per share for each class of common and participating securities according to dividends declared or accumulated and participation rights in undistributed earnings. The two-class method required earnings available to common stockholders for the period to be allocated between common and participating securities based upon their respective rights to share in the earnings as if all earnings for the period had been distributed. During periods of loss, there was no allocation required under the two-class method since the participating securities do not have a contractual obligation to fund the losses of the Company.

Foreign Currency

The accumulated other comprehensive loss on the balance sheet includes foreign currency translation adjustments through December 31, 2015 recorded in connection with the change in functional currency from the Canadian dollar to the U.S. dollar. Gains or losses resulting from transactions denominated in foreign currencies are recorded as a component of other income or expense, within the consolidated statements of operations and comprehensive loss.

Leases

At the inception of an arrangement, the Company determines whether the arrangement is or contains a lease based on the unique facts and circumstances present. Operating lease liabilities and their corresponding right-of-use assets are recorded based on the present value of lease payments over the expected lease term. The interest rate implicit in lease contracts is typically not readily determinable. As such, the Company utilizes its incremental borrowing rate, which is the rate incurred to borrow on a collateralized basis over a similar term an amount equal to the lease payments in a similar economic environment. Certain adjustments to the right-of-use asset may be required for items such as initial direct costs paid or incentives received.

The Company has elected to combine lease and non-lease components as a single component. The lease expense is recognized over the expected term on a straight-line basis. The lease term for all of the Company’s leases includes the non-cancellable period of the lease plus any additional periods covered by either a Company option to extend (or not to terminate) the lease that the Company is reasonably certain to exercise. Variable lease payments associated with the Company’s leases are recognized when the event, activity, or circumstance in the lease agreement on which those payments are assessed occurs. Variable lease payments are presented in the Company’s consolidated statements of operations and comprehensive loss in the same line item as expense arising from fixed lease payments for operating leases. Balances related to operating leases are recognized on the consolidated balance sheets as right-of-use assets, operating lease liabilities, current and operating lease liabilities, non-current.

Deferred Offering Costs

The Company had deferred offering costs, related to its recently completed IPO, consisting of legal, accounting and other fees and costs directly attributable to the Company’s IPO and are included with other assets, noncurrent in the consolidated balance sheets until the completion of the IPO. The deferred offering costs were offset against the proceeds received upon the completion of the IPO. As such, there were no deferred offering costs as of December 31, 2023. As of December 31, 2022, the Company recorded $1.9 million of deferred offering costs.

Contingent Consideration

Consideration paid related to the Myst Merger Agreement (see Note 7 - Asset Acquisition for additional information) may include potential future payments that are contingent upon the Company achieving certain milestones in the future. Contingent consideration liabilities are measured at their estimated fair value as of the date of the consolidated balance sheets using a probability-based income approach based on the monetary value of the milestone payment discounted for the likelihood of achieving the milestone and a present value factor based on the timing of when the milestone is expected to be achieved. Contingent consideration liabilities expected to be settled within 12 months after the balance sheet date are presented in current liabilities, with the non-current portion recorded under other liabilities, non-current in the consolidated balance sheets. Changes in the fair value of the contingent consideration are recorded as research and development expenses in the consolidated statement of operations and comprehensive loss.

Recently Adopted Accounting Pronouncements

In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments—Credit Losses (Topic 326)—Measurement of Credit Losses on Financial Instruments, which has been subsequently amended by ASU No. 2018-19, ASU No. 2019-04, ASU No. 2019-05, ASU No. 2019-10, ASU No. 2019-11 and ASU No. 2021-03 (“ASU 2016-13”). The provisions of ASU 2016-13 modify the impairment model to utilize an expected loss methodology in place of the currently used incurred loss methodology and require a consideration of a broader range of reasonable and supportable information to inform credit loss estimates. ASU 2016-13 was effective for the Company on January 1, 2023. The adoption did not have a material impact on the consolidated financial statements.

Recently Issued Accounting Pronouncements

In August 2020, the FASB issued ASU No. 2020-06, Debt—Debt with Conversion and Other Options (Subtopic 470-20) and Derivatives and Hedging Contracts in Entity’s Own Equity (Subtopic 815-40) (“ASU 2020-06”), which reduces the number of accounting models for convertible debt instruments and convertible preferred stock as well as amends the derivatives scope exception for contracts in an entity’s own equity. ASU 2020-06 is effective for the Company on January 1, 2024, with early adoption permitted. The Company is currently evaluating the potential impact that this standard may have on its consolidated financial statements and related disclosures.

In November 2023, the FASB issued ASU No. 2023-07, Segment Reporting (Topic 280)—Improvements to Reportable Segment Disclosures (“ASU 2023-07”). ASU 2023-07 requires that an entity disclose significant segment expenses impacting profit and loss that are regularly provided to the chief operating decision maker. The update is required to be applied retrospectively to prior periods presented, based on the significant segment expense categories identified and disclosed in the period of adoption. The amendments in ASU 2023-07 are required to be adopted for fiscal years beginning after December 15, 2023, and interim periods within fiscal years beginning after December 15, 2024. Early adoption is permitted. The Company is currently evaluating the potential impact that this standard may have on its consolidated financial statements and related disclosures.

In December 2023, the FASB issued ASU No. 2023-09, Income Taxes (Topic 740)—Improvements to Income Tax Disclosures (“ASU 2023-09”). ASU 2023-09 requires that an entity disclose specific categories in the effective tax rate reconciliation as well as provide additional information for reconciling items that meet a quantitative threshold. Further, ASU 2023-09 requires certain disclosures of state versus federal income tax expense and taxes paid. The amendments in ASU 2023-09 are required to be adopted for fiscal years beginning after December 15, 2024. Early adoption is permitted for annual financial statements that have not yet been issued. The amendments should be applied on a prospective basis although retrospective application is permitted. The Company

is currently evaluating the potential impact that this standard may have on its consolidated financial statements and related disclosures.

Legal Proceedings - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Commitments and Contingencies Disclosure [Abstract]
Loss contingency reserve for litigation liabilities	$ 0	$ 0

Net Loss per Share (Tables)

12 Months Ended

Dec. 31, 2023

Earnings Per Share [Abstract]

Schedule of dilutive securities excluded from computation of diluted net loss per share

The following outstanding potentially dilutive shares were excluded from the computation of diluted net loss per share attributable to common stockholders:


	Year Ended December 31,
		2023		2022
Redeemable convertible preferred stock			—		12,493,879
Restricted stock			90,740		181,480
Unvested RSUs			102,945		—
Options to purchase common stock			3,374,282		2,529,982
Total			3,567,967		15,205,341

Fair Value of Financial Assets and Liabilities (Tables)

12 Months Ended

Dec. 31, 2023

Fair Value Disclosures [Abstract]

Schedule of Financial Assets and Liabilities Measured on Recurring Basis at Fair Value

The following tables represent a summary of the financial assets and liabilities that are measured on a recurring basis at fair value (in thousands):


	December 31, 2023
	Level 1		Level 2		Level 3		Fair Value
Financial assets:
Money market funds	$	15,635					$	15,635
Restricted cash(1)		116		—		—		116
U.S. government and agency securities(2)		76,979		—		—		76,979
Total financial assets	$	92,730	$	—	$	—	$	92,730
Financial liabilities:
Contingent consideration(3)	$	—	$	—	$	916	$	916
Total financial liabilities	$	—	$	—	$	916	$	916


	December 31, 2022
	Level 1		Level 2		Level 3		Fair Value
Financial assets:
Money market funds	$	9,238	$	—	$	—	$	9,238
Restricted cash(1)		382		—		—		382
U.S. government and agency securities(2)		30,649		16,681		—		47,330
Total financial assets	$	40,269	$	16,681	$	—	$	56,950
Financial liabilities:
Contingent consideration(3)	$	—	$	—	$	5,994	$	5,994
Total financial liabilities	$	—	$	—	$	5,994	$	5,994

(1)

Restricted cash serves as deposits for the Company’s San Diego office lease as of December 31, 2023 and New York and San Diego office leases as of December 31, 2022.

(2)

Included in short-term investments on the consolidated balance sheets and are classified as available-for sale debt securities.

(3)

Contingent consideration related to the Myst Merger Agreement.

Schedule of Unobservable Input of Contingent Consideration Valuation

The following significant unobservable inputs were used in the valuation of the contingent consideration payable to the sole common stockholder of Myst pursuant to the Myst Merger Agreement:


	Fair Value as of
Contingent Consideration Liability	December 31, 2023		Valuation Technique	Unobservable Input	Range
	(in thousands)
Milestone payment for first	$	916	Discounted cash flow	Likelihood of occurrence	10%
registrational study (see Note 7				Discount rate	25%
- Asset Acquisition for additional information)				Expected term (in years)	3.5

	Fair Value as of
Contingent Consideration Liability	December 31, 2022		Valuation Technique	Unobservable Input	Range
	(in thousands)
Milestone payments	$	5,994	Discounted cash flow	Likelihood of occurrence	20% - 100%
				Discount rate	22%
				Expected term (in years)	0.25 - 2.75

Schedule of Company's Contingent Consideration Measured at Fair Value Level 3

The following table reflects the activity for the Company’s contingent consideration, measured at fair value using Level 3 inputs (in thousands):


Contingent consideration at December 31, 2022	$	5,994
Changes in the fair value of contingent consideration		109
Cash payment of Myst milestone		(2,375	)
Equity issuance related to milestone achievement		(2,812	)
Contingent consideration at December 31, 2023		916

Schedule of Company's Cash, Cash Equivalents and Available-for-Sale Securities

The following tables show the Company’s cash, cash equivalents and available-for-sale securities by significant investment category (in thousands):


	December 31, 2023
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value
Level 1: Money market funds	$	15,635	$	—	$	—	$	15,635
Restricted cash		116		—		—		116
U.S. government securities		76,875		104		—		76,979
Total financial assets	$	92,626	$	104	$	—	$	92,730
Classified as:
Cash and cash equivalents							$	15,635
Restricted cash								116
Short-term investments								76,979
							$	92,730


	December 31, 2022
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
Level 1: Money market funds	$	9,238	$	—	$	—		$	9,238
Restricted cash		382		—		—			382
U.S. government securities		30,761		—		(112	)		30,649
Level 2: U.S. agency securities		16,759		—		(78	)		16,681
Total financial assets	$	57,140	$	—	$	(190	)	$	56,950
Classified as:
Cash and cash equivalents								$	9,238
Restricted cash									382
Short-term investments									47,330
								$	56,950

Summary of Significant Accounting Policies (Policies)	12 Months Ended
Summary of Significant Accounting Policies (Policies)	Dec. 31, 2023
Accounting Policies [Abstract]
Basis of Presentation of Consolidated Financial Information	Basis of Presentation of Consolidated Financial Information The accompanying consolidated financial statements of the Company have been prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”) and pursuant to the rules and regulations of the SEC. Certain prior period amounts reported in the Company’s consolidated financial statements and accompanying notes have been reclassified to conform to the current period presentation. Any reference in these notes to applicable guidance is meant to refer to the authoritative accounting principles generally accepted in the United States as found in the Accounting Standard Codification (“ASC”) and Accounting Standards Update (“ASU”) of the Financial Accounting Standards Board (“FASB”).
Principles of Consolidation	Principles of Consolidation The accompanying consolidated financial statements include the accounts of the Company and its wholly owned subsidiaries. All intercompany balances and transactions have been eliminated in consolidation.
Use of Estimates	Use of Estimates The preparation of these consolidated financial statements in accordance with GAAP requires management to make estimates and assumptions that affect the amounts reported in the consolidated financial statements and accompanying notes. On an ongoing basis, management evaluates its estimates, including those related to accrued expenses, contingent liabilities, impairment of long-lived assets, revenue recognition, the valuation of equity-based compensation, common stock, restricted common stock, and income taxes. The Company bases its estimates on various assumptions that the Company believes to be reasonable under the circumstances. Actual results could differ from those estimates.
Segment Reporting	Segment Reporting The Company has determined that it operates and manages one operating segment, which is the business of developing and commercializing therapeutics. The Company’s chief operating decision maker, its chief executive officer, reviews financial information on an aggregate basis for the purpose of allocating resources.
Cash and Cash Equivalents	Cash and Cash Equivalents Cash and cash equivalents consist of checking, money market and highly liquid investments that are readily convertible to cash and that have an original maturity of three months or less from date of purchase. The carrying amounts approximate fair value due to the short maturities of these instruments.
Restricted Cash and Investments	Restricted Cash and Investments Restricted cash consists of certificate of deposit accounts that are pledged as collateral for the Company’s San Diego facility lease as of December 31, 2023 and the San Diego and New York facility leases as of December 31, 2022. Restricted cash was approximately $0.1 million and $0.4 million as of December 31, 2023 and 2022, respectively. The Company invests its excess cash in investment grade, short-term, fixed income securities and recognizes purchased securities on the settlement date. All investments have been classified as “available-for-sale” in the consolidated balance sheets and are carried at estimated fair value based upon quoted market prices or pricing models for similar securities. Management determines the appropriate classification of its investments at the time of purchase and re-evaluates such designation as of each balance sheet date. The Company assesses its available-for-sale securities under the available-for-sale security impairment model in ASC Topic 326, Financial Instruments—Credit Losses (“ASC 326”) as of each reporting date in order to determine if a portion of any decline in fair value below carrying value is the result of a credit loss. The Company records credit losses in the consolidated statements of operations and comprehensive loss as credit loss expense, which is limited to the difference between the fair value and the amortized cost of the security. To date, the Company has not recorded any credit losses on its available-for-sale securities. Declines in fair value below carrying value attributable to non-credit related factors are recorded as accumulated other comprehensive loss, which is a separate component of stockholders’ equity (deficit). Realized gains and losses are reported in other income (expense), net. Interest on short-term investments is included in other income (expense), net. The Company’s investments are classified as current assets which reflects management’s intention to use the proceeds from sales of these securities to fund its operations, as necessary.
Concentration of Credit Risk	Concentration of Credit Risk Financial instruments that potentially subject the Company to concentrations of credit risk consist principally of cash and cash equivalents, investments and restricted cash. The Company’s investment policy restricts cash investments to high credit quality, investment grade investments. The Company’s investment policy provides guidelines and limits regarding investment type, concentration, credit quality, and maturity aimed at maintaining sufficient liquidity to satisfy operating and working capital requirements along with strategic initiatives, preserving capital, and minimizing risk of capital loss while generating returns on its investments. The Company is exposed to credit risk in the event of default by the issuer or the institutions holding the cash and cash equivalents to the extent of the amounts recorded on the balance sheets. The Company records accounts receivable amounts invoiced to a collaborator, for which the Company has an unconditional right to consideration. For amounts to which the Company has an unconditional right to consideration but has not yet invoiced the collaborator, the Company records unbilled accounts receivable. The Company estimates an allowance for credit losses based on the creditworthiness of its collaborator, current economic conditions and future economic conditions, as may be applicable. If a receivable is deemed to be uncollectible, the balance is charged against the allowance. As of December 31, 2023 and December 31, 2022, the Company had an accounts receivable balance of $0.2 million and $8.7 million, respectively of which Takeda accounted for 100%, and no allowance was recorded. Accounts receivable and unbilled accounts receivable are presented in accounts receivable, net on the consolidated balance sheets. During the twelve months ended December 31, 2023 and 2022, the Company did not recognize any charges for write-offs of accounts receivable. The Company has no off-balance sheet risk, such as foreign exchange contracts, option contracts or other foreign-hedging arrangements.
Fair Value Measurements	Fair Value Measurements The Company applies fair value accounting for all financial assets and liabilities and non-financial assets and liabilities that are recognized or disclosed at fair value in the consolidated financial statements on a recurring basis. Fair value is defined as the exchange price that would be received for an asset or an exit price that would be paid to transfer a liability in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. The fair value hierarchy requires that an entity maximize the use of observable inputs when estimating fair value. The fair value hierarchy includes the following three-level classification which is based on the market observability of the inputs used for estimating the fair value of the assets or liabilities being measured: Level 1 – Quoted market prices in active markets for identical assets or liabilities. Level 2 – Observable inputs other than quoted prices in active markets for identical assets and liabilities, quoted prices for identical or similar assets or liabilities in inactive markets, or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities. Level 3 – Inputs that are generally unobservable and typically reflect management’s estimate of assumptions that a market participant would use in pricing the asset or liability. Fair value accounting is applied for all financial assets and liabilities and non-financial assets and liabilities that are recognized at fair value in the consolidated financial statements on a recurring basis (at least annually). To the extent the valuation is based on models or inputs that are less observable or unobservable in the market, the determination of fair values requires more judgment. Accordingly, the degree of judgment exercised by the Company in determining fair value is greatest for instruments categorized as Level 3. A financial instrument’s level within the fair value hierarchy is based on the lowest level of any input that is significant to the fair value measurement.
Investment Tax Credits	Investment Tax Credits The Company claims Scientific Research and Experimental Development (“SR&ED”) deductions and related investment tax credits for income tax purposes based upon management’s interpretation of the applicable legislation in the Income Tax Act (Canada). Investment tax credits are subject to Canada Revenue Agency review and assessment of the eligibility of the Company’s research expenditures. These tax credits are applied to reduce the related research and development expenses incurred in the year recognized. Actual investment tax credits received may differ from those estimated and recorded in these consolidated financial statements.
Property and Equipment	Property and Equipment Property and equipment are recorded at cost, less accumulated depreciation. Depreciation is computed using the straight-line method over the estimated useful lives of the respective assets, which are two to three years for computer equipment and software, and five years for laboratory, office equipment and furniture. Leasehold improvements are amortized over the shorter of the useful life or the remaining term of the lease.
Revenue Recognition	Revenue Recognition The Company enters into collaboration arrangements that may include the receipt of payments for up-front license fees, success-based milestone payments, full time equivalent based payments for research services, and royalties on any future sales of commercialized products that result from the collaborations. Effective January 1, 2017, the Company adopted the provisions of ASC Topic 606, Revenue from Contacts with Customers (“ASC 606”). Under ASC 606, an entity recognizes revenue when its customer obtains control of promised goods or services, in an amount that reflects the consideration which the entity expects to receive in exchange for those goods or services. To determine the appropriate amount of revenue to be recognized for arrangements determined to be within the scope of ASC 606, the Company performs the following five steps: (i) identification of the contract(s) with the customer, (ii) identification of the promised goods or services in the contract and determination of whether the promised goods or services are performance obligations, (iii) measurement of the transaction price, (iv) allocation of the transaction price to the performance obligations, and (v) recognition of revenue when (or as) the Company satisfies each performance obligation. The Company only applies the five-step model to contracts when it is probable that the entity will collect consideration it is entitled to in exchange for the goods or services it transfers to the customer. The Company accounts for a contract with a customer that is within the scope of ASC 606 when all of the following criteria are met: (i) the arrangement has been approved by the parties and the parties are committed to perform their respective obligations, (ii) each party’s rights regarding the goods or services to be transferred can be identified, (iii) the payment terms for the goods and services to be transferred can be identified, (iv) the arrangement has commercial substance and (v) collection of substantially all of the consideration to which the Company will be entitled in exchange for the goods or services that will be transferred to the customer is probable. The Company estimates the transaction price based on the amount of consideration the Company expects for transferring the promised goods or services in the contract. The consideration may include both fixed consideration and variable consideration. At the inception of each arrangement that includes variable consideration, the Company evaluates the amount of the potential payments and the likelihood that the payments will be received. The Company utilizes either the most likely amount method or expected value method to estimate the transaction price based on which method better predicts the amount of consideration expected to be received. If it is probable that a significant revenue reversal would not occur, the variable consideration is included in the transaction price. For arrangements that include development and regulatory milestone payments, the Company evaluates whether the milestones are considered probable of being reached and estimates the amount to be included in the transaction price using the most likely amount method. If it is probable that a significant revenue reversal would not occur, the associated milestone value is included in the transaction price. Milestone payments that are not within the Company’s control or the licensee’s control, such as regulatory approvals, are not considered probable of being achieved until those approvals are received. At the end of each reporting period, the Company re-evaluates the probability of achievement of such milestones and any related constraint, and if necessary, adjusts the estimate of the overall transaction price. Any such adjustments are recorded on a cumulative catch-up basis, which would affect collaboration revenue and net loss in the period of adjustment. For sales-based royalties, including milestone payments based on the level of sales, the Company determines whether the sole or predominant item to which the royalties relate is a license. When the license is the sole or predominant item to which the sales-based royalty relates, the Company recognizes revenue at the later of: (i) when the related sales occur, or (ii) when the performance obligation to which some or all of the royalty has been allocated has been satisfied (or partially satisfied). The Company allocates the transaction price based on the estimated standalone selling price. The Company must develop assumptions that require judgment to determine the standalone selling price for each performance obligation identified in the contract. The Company utilizes key assumptions to determine the standalone selling price, which may include other comparable transactions, pricing considered in negotiating the transaction and the estimated costs. Certain variable consideration is allocated specifically to one or more performance obligations in a contract when the terms of the variable consideration related to the satisfaction of the performance obligation and the resulting amounts allocated to each performance obligation are consistent with the amounts the Company would expect to receive for each performance obligation. For performance obligations, which consist of licenses and other promises, the Company utilizes judgment to assess the nature of the combined performance obligation in order to determine whether the combined performance obligation is satisfied over time or at a point in time. The Company determines the appropriate method of measuring progress of combined performance obligations satisfied over time for purposes of recognizing revenue determined on a contract by contract basis (See Note 6—Agreements for additional information). The Company evaluates the measure of progress each reporting period and, if necessary, adjusts the measure of performance and related revenue recognition. If the license to the Company’s intellectual property is determined to be distinct from the other performance obligations identified in the arrangement, the Company will recognize revenue from non-refundable, up-front fees allocated to the license when the license is transferred to the customer and the customer is able to use and benefit from the license. The Company receives payments from customers based on billing schedules established in each contract. Up-front payments and fees are recorded as deferred revenue upon receipt or when due until the Company performs its obligations under these arrangements. Amounts are recorded as accounts receivable when the Company’s right to consideration is unconditional.
Research and Development Expenses	Research and Development Expenses Research and development costs are expensed as incurred. Research and development costs consist of payroll and other personnel-related expenses, materials and supplies, preclinical expenses, manufacturing expenses, contract research and development services, and consulting costs, as well as allocations of facilities and other overhead costs. Costs of certain development activities, such as manufacturing, are recognized based on an evaluation of the progress to completion of specific tasks. Payments for these activities are based on the terms of the individual arrangements, which may differ from the pattern of costs incurred, and are reflected in the consolidated financial statements as prepaid or accrued research and development costs. Non-refundable advance payments for goods or services to be received in the future for use in research and development activities are deferred and capitalized. The capitalized amounts are expensed as the related goods are delivered or the services are performed. Costs associated with collaboration agreements are included in research and development expenses. Assets acquired that are used for research and development and which have no alternative use are expensed to research and development costs.
Preclinical and Clinical Trial Accruals	Preclinical and Clinical Trial Accruals The Company makes estimates of its accrued expenses as of each balance sheet date in the consolidated financial statements based on the facts and circumstances known at that time. Accrued expenses for preclinical studies and clinical trials are based on estimates of costs incurred and fees that may be associated with services provided by contract research organizations (“CROs”), clinical trial investigational sites and other clinical trial-related activities. Payments under certain contracts with such parties depend on factors such as successful enrollment of patients, site initiation and the completion of clinical trial milestones. In accruing for these services, the Company estimates the time period over which services will be performed and the level of effort to be expended in each period. If possible, the Company obtains information regarding unbilled services directly from these service providers. However, the Company may be required to estimate these services based on other available information. If the Company underestimates or overestimates the activities or fees associated with a study or service at a given point in time, adjustments to research and development expenses may be necessary in future periods. Historically, estimated accrued liabilities have approximated actual expenses incurred. Subsequent changes in estimates may result in a material change in accruals.
Patent Costs	Patent Costs All patent-related costs incurred in connection with filing and prosecuting patent applications are expensed as incurred due to the uncertainty about the recovery of the expenditure. Amounts incurred are classified as general and administrative expenses.
Stock-Based Compensation	Stock-Based Compensation The Company accounts for stock-based compensation expense related to stock options and restricted stock units, ("RSUs"), by estimating the fair value on the date of grant. The Company estimates the fair value of stock options granted to employees and non-employees using the Black-Scholes option pricing model. The fair value of RSUs granted to employees is the closing price of the Company’s common stock on the date of grant. The Company recognizes stock-based compensation expense, over the requisite service period, based on the vesting provisions of the individual grants. Generally, the Company issues stock-based awards with only service-based vesting conditions and records the expense for these awards using the straight-line method. The Company accounts for forfeitures when they occur. The Black-Scholes option pricing model requires inputs based on certain subjective assumptions, including (a) the expected stock price volatility, (b) the expected term of the award, (c) the risk-free interest rate and (d) expected dividend yields. Due to the lack of a public market for the Company’s common stock until July 21, 2023, and lack of company- specific historical and implied volatility data, the Company has based its computation of expected volatility on the average historical volatility of a representative group of public companies with similar characteristics to the Company, including stage of product development and life science industry focus. The historical volatility is calculated based on a period of time commensurate with the expected term. The Company uses the simplified method as prescribed by the U.S. Securities and Exchange Commission Staff Accounting Bulletin No. 107, Share-Based Payment, to calculate the expected term for options granted to employees as it does not have sufficient historical exercise data to provide a reasonable basis upon which to estimate the expected term. The expected term is applied to the stock option grant group as a whole, as the Company does not expect substantially different exercise or post-vesting termination behavior among its employee population. The risk-free interest rate is based on a treasury instrument whose term is consistent with the expected term of the stock options. The expected dividend yield is assumed to be zero as the Company has never paid dividends and has no current plans to pay any dividends on its common stock.
Determination of Fair Value of Common Stock	Determination of Fair Value of Common Stock After the Company's IPO in July 2023, the fair value of common stock is determined using the closing price of the Company's common stock on the Nasdaq Global Select Market. Prior to the IPO, there were significant judgments and estimates inherent in the determination of the fair value of the Company’s common stock. These estimates and assumptions include a number of objective and subjective factors, including, among other things, external market conditions, the prices at which the Company sold shares of its convertible preferred stock, the superior rights and preferences of securities senior to its common stock at the time of, and the likelihood of, achieving a liquidity event, such as an initial public offering or sale of the Company. The approach to estimating the fair market value of common stock is consistent with the methods outlined in the American Institute of Certified Public Accountants’ Accounting and Valuation Guide, Valuation of Privately-Held Company Equity Securities Issued as Compensation (“Practice Aid”). In valuing the Company’s common stock prior to the IPO, the equity value of the business was determined using the backsolve method, a form of the subject company transaction method, wherein the equity value for a privately held company is derived from a recent transaction in the company’s own securities. The value is then allocated using the hybrid method allocation methodology. For grants made prior to September 30, 2018, in accordance with the Practice Aid, the Company determined the option pricing method (“OPM”), was the most appropriate method for determining the fair value of the Company’s common stock based on its stage of development and other relevant factors. For grants made subsequent to September 30, 2018 but prior to the IPO, the Company used a hybrid method, which is a hybrid between the OPM and the probability-weighted expected return method (“PWERM”). The hybrid method is a combination of the PWERM and OPM. The OPM allocates the overall Company value to the various share classes based on differences in liquidation preferences, participation rights, dividend policy and conversion rights, using a series of call options. The call right is valued using a Black-Scholes option pricing model. The PWERM employs additional information not used in the OPM, including various market approach calculations depending upon the likelihood of various discrete future liquidity scenarios, such as an initial public offering or sale of the Company, as well as the probability of remaining a private company. In a hybrid method, various exit scenarios are analyzed. A discount for lack of marketability of the Company’s common stock was then applied to arrive at an indication of value for the common stock.
Impairment of Long-Lived Assets	Impairment of Long-Lived Assets The Company reviews long-lived assets for impairment whenever events or changes in circumstances indicate that the carrying amount of such assets may not be recoverable, including evaluating the impact of the overall micro- and macro-economic conditions on the carrying value of its long-lived assets, including property and equipment and operating lease assets. During the twelve months ended December 31, 2023, the Company's stock price and resulting market capitalization experienced a significant, sustained decline. Accordingly, the Company assessed our long-lived assets, including property and equipment and operating lease assets for impairment. Recoverability of these assets is determined by comparing the forecasted undiscounted net cash flows of the operation to which the assets relate to the carrying amount. If the operation is determined to be unable to recover the carrying amount of its assets, then these assets are written down first to fair value Fair value is determined based on discounted cash flows or appraised values, depending on the nature of the assets. The Company recognized long-lived asset impairment charges of $1.6 million and $0.5 million for the years ended December 31, 2023 and 2022, respectively (See Note 4—Property and Equipment, Net and Note 11—Leases for additional information).
Redeemable Convertible Preferred Stock	Redeemable Convertible Preferred Stock The Company records all proceeds from redeemable convertible preferred stock (“Preferred Stock”) net of issuance costs. The Company classifies Preferred Stock outside of stockholders’ equity (deficit) due to certain events that are outside of the Company’s control, including sale or transfer of control of the Company, or redemption upon the election of the required majority of the Preferred Stockholders any time after June 29, 2026, as holders of the Preferred Stock could cause redemption of the shares in these situations. The Company adjusts the carrying values of the Preferred Stock to the ultimate redemption values over the period from issuance to the earliest redemption date. Upon the closing of the IPO, all of the outstanding shares of Preferred Stock automatically converted into shares of common stock in a 1-for-7.9872 reverse stock split.
Income Taxes	Income Taxes The Company accounts for the effect of income taxes in its consolidated financial statements using the asset and liability method in accordance with ASC Topic 740, Income Taxes (“ASC 740”). This process involves estimating actual current tax liabilities together with assessing the impact of carryforward and temporary differences resulting from the differing treatment of items such as depreciation for tax and accounting purposes. These differences result in deferred tax assets and liabilities which are measured using enacted tax rates expected to apply to taxable income in the year in which those temporary differences are expected to reverse. The Company regularly assesses the likelihood that the deferred income tax assets will be realized. A valuation allowance to reduce the deferred tax assets to the amount that the Company believes is more likely than not to be realized is established based on their judgement of all available positive and negative evidence. The assessment is completed on a taxing jurisdiction basis for each tax-paying component and takes into account a number of types of evidence, including: • the nature and history of current or cumulative financial reporting income or losses; • sources of future taxable income; • the anticipated reversal or expiration dates of deferred tax assets; and • tax planning strategies. The Company has established a valuation allowance to offset its gross deferred tax assets as of December 31, 2023 and 2022 due to the uncertainty of realizing future tax benefits primarily related to net operating loss carryforwards and income tax credits in Canada. The Company applies ASC 740-10 Income Taxes which requires a two-step approach to recording a tax benefit in the consolidated financial statements. The first step requires an evaluation of the tax position to determine whether it is “more likely than not”, based on the technical merits, that it will be sustained on audit. Provided that the tax position satisfies the recognition step, the Company then measures and records the position at the largest amount of tax benefit that is greater than 50 percent likely of being realized upon settlement of the audit. The Company considers many factors when evaluating and estimating its tax positions and tax benefits, which may require periodic adjustments and may not accurately anticipate actual outcomes. The Company recognizes accrued interest and penalties related to unrecognized tax benefits. There were no accrued interest and penalties as of December 31, 2023.
Net Loss Per Share	Net Loss Per Share Basic net loss per share attributable to common stockholders is calculated by dividing the net loss attributable to common stockholders by the weighted-average number of shares of common stock outstanding during the period. Diluted net loss per share is computed by giving effect to all potentially dilutive securities outstanding for the period using the treasury stock method or the if-converted method based on the nature of such securities. For periods in which the Company reports net losses, diluted net loss per common share attributable to common stockholders is the same as basic net loss per common share attributable to common stockholders, because potentially dilutive common shares are not assumed to have been issued if their effect is anti-dilutive. Prior to the Company's IPO, the Company applied the two-class method to compute basic and diluted net loss per share because it had issued redeemable convertible preferred stock that met the definition of participating securities. The two-class method determined net loss per share for each class of common and participating securities according to dividends declared or accumulated and participation rights in undistributed earnings. The two-class method required earnings available to common stockholders for the period to be allocated between common and participating securities based upon their respective rights to share in the earnings as if all earnings for the period had been distributed. During periods of loss, there was no allocation required under the two-class method since the participating securities do not have a contractual obligation to fund the losses of the Company.
Foreign Currency	Foreign Currency The accumulated other comprehensive loss on the balance sheet includes foreign currency translation adjustments through December 31, 2015 recorded in connection with the change in functional currency from the Canadian dollar to the U.S. dollar. Gains or losses resulting from transactions denominated in foreign currencies are recorded as a component of other income or expense, within the consolidated statements of operations and comprehensive loss.
Leases	Leases At the inception of an arrangement, the Company determines whether the arrangement is or contains a lease based on the unique facts and circumstances present. Operating lease liabilities and their corresponding right-of-use assets are recorded based on the present value of lease payments over the expected lease term. The interest rate implicit in lease contracts is typically not readily determinable. As such, the Company utilizes its incremental borrowing rate, which is the rate incurred to borrow on a collateralized basis over a similar term an amount equal to the lease payments in a similar economic environment. Certain adjustments to the right-of-use asset may be required for items such as initial direct costs paid or incentives received. The Company has elected to combine lease and non-lease components as a single component. The lease expense is recognized over the expected term on a straight-line basis. The lease term for all of the Company’s leases includes the non-cancellable period of the lease plus any additional periods covered by either a Company option to extend (or not to terminate) the lease that the Company is reasonably certain to exercise. Variable lease payments associated with the Company’s leases are recognized when the event, activity, or circumstance in the lease agreement on which those payments are assessed occurs. Variable lease payments are presented in the Company’s consolidated statements of operations and comprehensive loss in the same line item as expense arising from fixed lease payments for operating leases. Balances related to operating leases are recognized on the consolidated balance sheets as right-of-use assets, operating lease liabilities, current and operating lease liabilities, non-current.
Deferred Offering Costs	Deferred Offering Costs The Company had deferred offering costs, related to its recently completed IPO, consisting of legal, accounting and other fees and costs directly attributable to the Company’s IPO and are included with other assets, noncurrent in the consolidated balance sheets until the completion of the IPO. The deferred offering costs were offset against the proceeds received upon the completion of the IPO. As such, there were no deferred offering costs as of December 31, 2023. As of December 31, 2022, the Company recorded $1.9 million of deferred offering costs.
Contingent Consideration	Contingent Consideration Consideration paid related to the Myst Merger Agreement (see Note 7 - Asset Acquisition for additional information) may include potential future payments that are contingent upon the Company achieving certain milestones in the future. Contingent consideration liabilities are measured at their estimated fair value as of the date of the consolidated balance sheets using a probability-based income approach based on the monetary value of the milestone payment discounted for the likelihood of achieving the milestone and a present value factor based on the timing of when the milestone is expected to be achieved. Contingent consideration liabilities expected to be settled within 12 months after the balance sheet date are presented in current liabilities, with the non-current portion recorded under other liabilities, non-current in the consolidated balance sheets. Changes in the fair value of the contingent consideration are recorded as research and development expenses in the consolidated statement of operations and comprehensive loss.
Recently Adopted Accounting Pronouncements	Recently Adopted Accounting Pronouncements In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments—Credit Losses (Topic 326)—Measurement of Credit Losses on Financial Instruments, which has been subsequently amended by ASU No. 2018-19, ASU No. 2019-04, ASU No. 2019-05, ASU No. 2019-10, ASU No. 2019-11 and ASU No. 2021-03 (“ASU 2016-13”). The provisions of ASU 2016-13 modify the impairment model to utilize an expected loss methodology in place of the currently used incurred loss methodology and require a consideration of a broader range of reasonable and supportable information to inform credit loss estimates. ASU 2016-13 was effective for the Company on January 1, 2023. The adoption did not have a material impact on the consolidated financial statements.
Recently Issued Accounting Pronouncements	Recently Issued Accounting Pronouncements In August 2020, the FASB issued ASU No. 2020-06, Debt—Debt with Conversion and Other Options (Subtopic 470-20) and Derivatives and Hedging Contracts in Entity’s Own Equity (Subtopic 815-40) (“ASU 2020-06”), which reduces the number of accounting models for convertible debt instruments and convertible preferred stock as well as amends the derivatives scope exception for contracts in an entity’s own equity. ASU 2020-06 is effective for the Company on January 1, 2024, with early adoption permitted. The Company is currently evaluating the potential impact that this standard may have on its consolidated financial statements and related disclosures. In November 2023, the FASB issued ASU No. 2023-07, Segment Reporting (Topic 280)—Improvements to Reportable Segment Disclosures (“ASU 2023-07”). ASU 2023-07 requires that an entity disclose significant segment expenses impacting profit and loss that are regularly provided to the chief operating decision maker. The update is required to be applied retrospectively to prior periods presented, based on the significant segment expense categories identified and disclosed in the period of adoption. The amendments in ASU 2023-07 are required to be adopted for fiscal years beginning after December 15, 2023, and interim periods within fiscal years beginning after December 15, 2024. Early adoption is permitted. The Company is currently evaluating the potential impact that this standard may have on its consolidated financial statements and related disclosures. In December 2023, the FASB issued ASU No. 2023-09, Income Taxes (Topic 740)—Improvements to Income Tax Disclosures (“ASU 2023-09”). ASU 2023-09 requires that an entity disclose specific categories in the effective tax rate reconciliation as well as provide additional information for reconciling items that meet a quantitative threshold. Further, ASU 2023-09 requires certain disclosures of state versus federal income tax expense and taxes paid. The amendments in ASU 2023-09 are required to be adopted for fiscal years beginning after December 15, 2024. Early adoption is permitted for annual financial statements that have not yet been issued. The amendments should be applied on a prospective basis although retrospective application is permitted. The Company is currently evaluating the potential impact that this standard may have on its consolidated financial statements and related disclosures.

Cover Page - USD ($)	12 Months Ended
Cover Page - USD ($)	Dec. 31, 2023	Mar. 05, 2024
Document Information [Line Items]
Document Type	10-K
Document Annual Report	true
Document Transition Report	false
Amendment Flag	false
Document Period End Date	Dec. 31, 2023
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	FY
Entity Registrant Name	Turnstone Biologics Corp.
Entity Central Index Key	0001764974
Entity File Number	001-41747
Entity Tax Identification Number	83-2909368
Entity Incorporation, State or Country Code	DE
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Shell Company	false
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	true
ICFR Auditor Attestation Flag	false
Document Financial Statement Error Correction [Flag]	false
Entity Ex Transition Period	false
Entity Address, Address Line One	9310 Athena Circle
Entity Address, Address Line Two	Suite 300
Entity Address, City or Town	La Jolla
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	92037
City Area Code	347
Local Phone Number	897-598
Title of 12(b) Security	Common Stock ($0.001 par value)
Trading Symbol	TSBX
Security Exchange Name	NASDAQ
Entity Common Stock, Shares Outstanding		23,099,335
Documents Incorporated by Reference	DOCUMENTS INCORPORATED BY REFERENCE Portions of the registrant’s definitive proxy statement for the 2024 Annual Meeting of Stockholders, which will be filed with the Securities and Exchange Commission within 120 days after the registrant's fiscal year ended December 31, 2023, are incorporated by reference into Part III of this Annual Report on Form 10-K where indicated.
Entity Public Float	$ 0
Auditor Name	Ernst & Young LLP
Auditor Location	San Diego, California
Auditor Firm ID	42

Accrued Expenses and Other Current Liabilities - Schedule of Accrued Liabilities and Other Current Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Accrued Liabilities and Other Liabilities [Abstract]
Research and development expense	$ 5,675	$ 6,688
Professional and consulting expense	641	1,170
Compensation	3,593	2,366
Contingent consideration, current		3,791
Other current liabilities		272
Total accrued expenses and other current liabilities	$ 9,909	$ 14,287

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Preferred stock, par or stated value per Share	$ 0.001	$ 0.001
Preferred stock, shares authorized	10,000,000	0
Preferred stock, shares, issued	0	0
Preferred stock, shares, outstanding	0	0
Common stock, par or stated value per Share	$ 0.001	$ 0.001
Common stock, shares authorized	490,000,000	147,892,358
Common stock, shares, outstanding	23,099,335	2,915,757
Common stock, shares, issued	23,099,335	2,915,757
Series A redeemable convertible preferred stock [Member]
Temporary equity, par or stated value per share	$ 0.001	$ 0.001
Temporary equity, shares authorized	0	11,250,000
Temporary equity, shares issued	0	11,250,000
Temporary equity, shares outstanding	0	11,250,000
Temporary Equity, aggregate amount of redemption requirement	$ 0	$ 8,643
Series B-1 redeemable convertible preferred stock [Member]
Temporary equity, par or stated value per share	$ 0.001	$ 0.001
Temporary equity, shares authorized	0	16,285,156
Temporary equity, shares issued	0	16,285,156
Temporary equity, shares outstanding	0	16,285,156
Temporary Equity, aggregate amount of redemption requirement	$ 0	$ 12,611
Series B-2 redeemable convertible preferred stock [Member]
Temporary equity, par or stated value per share	$ 0.001	$ 0.001
Temporary equity, shares authorized	0	25,065,538
Temporary equity, shares issued	0	25,065,538
Temporary equity, shares outstanding	0	25,065,538
Temporary Equity, aggregate amount of redemption requirement	$ 0	$ 28,860
Series C redeemable convertible preferred stock [Member]
Temporary equity, par or stated value per share	$ 0.001	$ 0.001
Temporary equity, shares authorized	0	17,905,288
Temporary equity, shares issued	0	17,905,288
Temporary equity, shares outstanding	0	17,905,288
Temporary Equity, aggregate amount of redemption requirement	$ 0	$ 42,100
Series D redeemable convertible preferred stock [Member]
Temporary equity, par or stated value per share	$ 0.001	$ 0.001
Temporary equity, shares authorized	0	29,285,356
Temporary equity, shares issued	0	29,285,356
Temporary equity, shares outstanding	0	29,285,356
Temporary Equity, aggregate amount of redemption requirement	$ 0	$ 80,000

Redeemable Convertible Preferred Stock and Stockholders' Equity - Summary Of Shares Of Common Stock Reserved For Future Issuance (Detail) - shares	Dec. 31, 2023	Dec. 31, 2022
Class of Stock [Line Items]
Common stock reserved for future issuance	5,454,918	15,279,546
Common stock options outstanding [Member]
Class of Stock [Line Items]
Common stock reserved for future issuance	3,374,282	2,529,982
Unvested RSUs [Member]
Class of Stock [Line Items]
Common stock reserved for future issuance	102,945
Shares available for issuance under the ESPP [Member]
Class of Stock [Line Items]
Common stock reserved for future issuance	222,287
Shares available for issuance under the Plans [Member]
Class of Stock [Line Items]
Common stock reserved for future issuance	1,755,404	255,685
Series A redeemable convertible preferred stock [Member]
Class of Stock [Line Items]
Common stock reserved for future issuance		1,408,502
Series B-1 redeemable convertible preferred stock [Member]
Class of Stock [Line Items]
Common stock reserved for future issuance		2,038,903
Series B-2 redeemable convertible preferred stock [Member]
Class of Stock [Line Items]
Common stock reserved for future issuance		3,138,208
Series C redeemable convertible preferred stock [Member]
Class of Stock [Line Items]
Common stock reserved for future issuance		2,241,740
Series D redeemable convertible preferred stock [Member]
Class of Stock [Line Items]
Common stock reserved for future issuance		3,666,526

Consolidated Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Collaboration revenue	$ 19,306	$ 73,300
Operating expenses:
Research and development	60,491	86,703
General and administrative	17,847	18,223
Total operating expenses	78,338	104,926
Loss from operations	(59,032)	(31,626)
Other income, net	3,546	933
Net loss before income taxes	(55,486)	(30,693)
Benefit (provision) for income taxes	286	(141)
Net loss	(55,200)	(30,834)
Other comprehensive income (loss):
Unrealized gain (loss) on available-for-sale debt securities	294	(168)
Total comprehensive loss	(54,906)	(31,002)
Net loss	(55,200)	(30,834)
Less: accretion of preferred stock to redemption value	(39)	(190)
Net loss attributable to common stockholders, basic	(55,239)	(31,024)
Net loss attributable to common stockholders, diluted	$ (55,239)	$ (31,024)
Weighted-average shares of common stock outstanding, basic	11,562,910	2,484,569
Weighted-average shares of common stock outstanding, diluted	11,562,910	2,484,569
Net loss per share attributable to common stockholders, basic	$ (4.78)	$ (12.49)
Net loss per share attributable to common stockholders, diluted	$ (4.78)	$ (12.49)

Income Taxes - Schedule of Components of Net Loss Before Income Taxes (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Income Tax Disclosure [Abstract]
Domestic	$ (52,765)	$ (22,065)
Foreign	(2,721)	(8,628)
Net loss before income taxes	$ (55,486)	$ (30,693)

- Definition

Amount of income (loss) from continuing operations, including income (loss) from equity method investments, before deduction of income tax expense (benefit), and income (loss) attributable to noncontrolling interest.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 944
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-04(11))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483586/944-220-S99-1

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 22
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-22

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 30
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-30

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 32
-Subparagraph (f)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-32

Reference 5: http://www.xbrl.org/2003/role/exampleRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 31
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-31

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 32
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-32

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 942
-SubTopic 235
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-05(b)(2))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479557/942-235-S99-1

Reference 8: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Section 25
-Paragraph 1
-SubTopic 20
-Topic 940
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481913/940-20-25-1

Reference 9: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 220
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03(10))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483621/220-10-S99-2

Reference 10: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 942
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04(15))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483589/942-220-S99-1

+ Details

Agreements

12 Months Ended

Dec. 31, 2023

Agreements [Abstract]

Agreements

6. Agreements

Takeda Pharmaceutical Company Limited

Collaboration Agreement

In November 2019, the Company entered into a discovery, collaboration and license agreement (“Takeda Agreement”) with Millennium Pharmaceuticals, Inc. (also known as Takeda Oncology), a wholly owned subsidiary of Takeda Pharmaceutical Company Limited (Takeda). Under the Takeda Agreement, the Company agreed to collaborate with Takeda to co-develop and co-commercialize TBio-6517 (also known as RIVAL-01) (“Development Program”) and to conduct discovery programs to identify additional novel product candidates based on its vaccinia virus platform for independent development (“Discovery Program”).

Under the Takeda Agreement, the Company granted Takeda and its affiliates a worldwide, irrevocable, non-transferable, co-exclusive, sublicensable license under certain of the Company’s know-how and patent rights (“Turnstone Technology”) to make, use, sell, offer for sale, develop, manufacture, and commercialize, or otherwise exploit TBio-6517 (“Licensed Compound”) and products containing TBio-6517 (“Takeda Licensed Products”) in all fields. Takeda granted the Company and the Company’s affiliates an irrevocable, non-transferable, non-exclusive, sublicensable license under certain know-how and patent rights of Takeda (“Takeda Technology”) to make, use, sell, offer for sale, develop, manufacture, and commercialize, or otherwise exploit the Licensed Compound and Takeda Licensed Products in all fields in accordance with joint development, commercialization, and medical affairs plans under the Takeda Agreement. Under the Takeda Agreement, the Company also granted to Takeda and its affiliates a worldwide, non-transferable, non-exclusive, sublicensable license under Turnstone Technology to conduct joint discovery and research activities in all fields in accordance with joint research and discovery plans. Under the Takeda Agreement, Takeda granted the Company a license to Takeda Technology to conduct discovery and research activities in all fields in accordance with joint research and discovery plans. The Company also granted to Takeda and its affiliates an exclusive option to obtain a worldwide, irrevocable, non-transferable, exclusive, sublicensable license under Turnstone Technology to make, use, sell, offer for sale, develop, manufacture, and commercialize, or otherwise exploit (i) selected discovery virus candidates generated and evaluated by the parties under a joint discovery program (“Selected Discovery Candidates”), and (ii) any corresponding licensed products containing a Selected Discovery Candidate (“Licensed Discovery Products”). Takeda may exercise this option with

respect to two virus candidates and within a specified option exercise period. The Company granted Takeda and its affiliates a non-exclusive, perpetual, irrevocable, worldwide, sublicensable and fully paid-up license under certain of the Company’s know-how and patents relating to manufacturing improvements developed under the Takeda Agreement solely for use in connection with the manufacture of products that do not comprise or incorporate, and that are not based on, an oncolytic virus. Takeda granted the Company and the Company’s affiliates a non-exclusive, perpetual, irrevocable, worldwide, sublicensable and fully paid-up license under certain of Takeda’s know-how and patents relating to manufacturing improvements developed under the Takeda Agreement solely for use in connection with the manufacture of any and all products. With respect to discovery virus candidates for which Takeda does not exercise its option, Takeda granted the Company a non-exclusive, perpetual, worldwide, sublicensable and royalty-bearing license under certain of its know-how and patents that is necessary or reasonably useful for the exploitation of such declined discovery virus candidates (“Declined Candidate License”).

Responsibilities for the development of Licensed Compounds and Takeda Licensed Products are delineated pursuant to a joint development plan under the terms of the Takeda Agreement. The Company will be responsible for all activities under the joint development plan prior to completion of a Phase 2a clinical trial and Takeda will be responsible for all activities in the joint development plan upon and after completion of the Phase 2a clinical trial. Responsibilities relating to manufacturing, medical affairs, and commercialization of Licensed Compounds and Takeda Licensed Products are delineated pursuant to a manufacturing working plan, joint medical affairs plan and joint commercialization plan, respectively. The Company has the right to reduce or opt-out of its share of responsibilities for costs and expenses of certain development or commercialization activities for the Takeda Licensed Compounds and Takeda Licensed Products. Responsibilities for the discovery and research of Selected Discovery Candidates are delineated pursuant to joint discovery and research plans under the terms of the Takeda Agreement.

Under the Takeda Agreement, Takeda paid the Company a non-refundable payment of $50.0 million in November 2019 and an additional non-refundable payment of $30.0 million in April, 2020, for the option to license up to two Selected Discovery Candidates, with additional consideration of $15.0 million to be paid by Takeda to the Company for each exercise of such option.

Under the Takeda Agreement, the Company has the right to reduce its share of funding obligations with respect to development activities for the Licensed Compound and Takeda Licensed Products (the “Development Opt-Down Right”), or to opt-out of all further funding obligations with respect to development activities for the Licensed Compound and Takeda Licensed Products (the “Development Opt-Out Right”). Unless and until the Company exercises the Development Opt-Down Right, the parties will share evenly in any operating profits or losses with respect to joint development activities, joint medical affairs activities, and joint commercialization activities. If the Company exercises its Development Opt-Down Right, then starting from the effective date of the exercise of the right, Takeda will bear (and be entitled to) 70% and the Company will bear (and be entitled to) 30% of the operating profits or losses with respect to joint development activities, joint medical affairs activities, and joint commercialization activities. Takeda is obligated to pay the Company (i) up to $200.0 million in aggregate upon achievement of certain clinical and regulatory milestones for the first Takeda Licensed Product to achieve the applicable development milestone event, (ii) up to $150.0 million in aggregate for one-time payments upon achievement of certain sales milestones for each Takeda Licensed Product, (iii) up to $240.0 million in aggregate (if Takeda exercises both options to Selected Discovery Candidates) upon achievement of certain clinical and regulatory milestones for the first Takeda Licensed Discovery Product to achieve applicable development milestone events, and (iv) up to $300.0 million in aggregate (if Takeda exercises both options to Selected Discovery Candidates) for one-time payments upon achievement of certain sales milestones for a Licensed Discovery Product. If the Company exercises its Development Opt-Out Right for the Takeda Licensed Products, then in lieu of the profit and loss share arrangement described above, the Company is entitled to receive tiered low- to high- teen percentage royalties on net sales of all Takeda Licensed Products by the Company or the Company’s sublicensees during the royalty term, which commences on the first commercial sale of a Takeda Licensed Product in a country and ends on the later of the expiration of all licensed patents covering such Licensed Product in such country or ten years after the date of the first commercial sale in such country (“Royalty Term”). For Licensed Discovery Products, the Company is entitled to receive tiered high-single digit to low-teen percentage royalties on net sales of all Licensed Discovery Products by the Company or the Company’s sublicensees during the Royalty Term. Royalty payments are subject to customary reductions.

Takeda has the right to terminate for convenience as follows: (i) prior to the expiration of the option exercise period related to a Discovery Virus Candidate, Takeda may terminate the Takeda Agreement related to such Discovery Virus Candidate and the Discovery Program with 90 days’ notice, (ii) prior to any commercial sale, Takeda may terminate the Takeda Agreement either in its entirety or on a compound-by-compound or region-by-region basis, with six months’ notice and (iii) after a commercial sale, Takeda may terminate the Takeda Agreement either in its entirety or on a compound-by-compound or region-by-region basis, with 12 months’ notice.

Termination of Development Program

On June 13, 2022, Takeda provided six months’ written notice to terminate the Development Program in accordance with its termination for convenience rights, with such termination being effective as of December 13, 2022. During the six months’ notice period, the Company was obligated to continue providing the necessary Development Program services to wind down the program. Upon the effective termination date of December 13, 2022, Takeda’s co-exclusive license to TBio-6517 terminated and the Company is no longer obligated to pursue development of TBio-6517.

Termination of Discovery Program

On January 6, 2023, Takeda provided six months’ written notice to terminate the remainder of the Takeda Agreement, with such termination being effective as of July 6, 2023 (“Effective Termination Date”). On the Effective Termination Date, all options and licenses granted under the Takeda Agreement terminated (except for the Declined Candidate License) and Takeda granted the Company a non-exclusive license under the patent rights and know-how controlled by Takeda as of the Effective Termination Date necessary for the Company to exploit the Licensed Compound and Takeda Licensed Products in the form existing as of the Effective Termination Date for any use worldwide, subject to a royalty to be agreed upon by Takeda and the Company. As of March 31, 2023, the Company ceased all work under the Takeda Agreement and there were no remaining estimated services associated with the obligations under the Takeda Agreement as of the effective termination date of July 6, 2023.

Accounting Analysis

The Company assessed the promised goods and services under the Takeda Agreement in accordance with ASC 606, and determined that, at inception, the Takeda Agreement includes the following performance obligations: (i) research, development and manufacturing services under the Development Program for the completion of clinical trials through Phase 2a for RIVAL-01 and a co-exclusive license to exploit RIVAL-01 (“Development Program Performance Obligation”); and (ii) research and development services under the Discovery Program to identify and optimize four Selected Discovery Candidates for further development (“Discovery Program Performance Obligation”). The individual promises under the Development Program including research, development, manufacturing for clinical trials, and the co-exclusive license to RIVAL-01 are not individually distinct as they represent inputs into a combined output of advancing RIVAL-01 through the Phase 2a clinical trial. Therefore, all promises under the Development Program represent a single performance obligation. Similarly, the research and development services under the Discovery Program represent a single research program aimed at generating four Selected Discovery Candidates and therefore represents a single performance obligation. The Development Program promises are distinct from the promises under the Discovery Program, as the benefits under each program are separately identifiable. Each program has a separate work plan and the promises to be provided under the Development Program do not relate to the promises to be provided under the Discovery Program.

The Company concluded that Takeda’s license options under the Discovery Program do not represent material rights, and therefore are not performance obligations, as the Company is entitled to an additional $15.0 million payment for each license option exercised, which approximates the estimated standalone selling price of the underlying license.

•

Fixed consideration of $80.0 million including a non-refundable up-front payment of $50.0 million in November 2019 and another non-refundable payment of $30.0 million that was due on April 1, 2020 and received in April 2020.

•

Variable consideration related to the expense sharing under the Development Program. These amounts are determinable based on the Development Program plan and budget, and the Company has a contractual right to the payment of costs incurred under the agreed upon plan. Consistent with the expected value method, the Company estimated that it will receive $58.6 million under the expense sharing through the completion of the Phase IIa clinical trial. The Company has concluded that these amounts do not require a constraint and are included in the transaction price at inception. The Company has evaluated this estimate at each reporting date and updated the estimate based on information available.

•

Variable consideration for the development milestones under the Development Program. The Company uses the most likely amount method to value this variable consideration as there are only two possible outcomes of achieving the individual milestones. Under the Development Program, the first milestone of $20.0 million is due upon acceptance of the IND by the FDA. At inception, the Company concluded that achievement of this milestone was highly probable and therefore the $20.0 million was included in the transaction price and was received in March 2020. The second milestone of $15.0 million under the Development Program is due upon the initiation of the first Phase 2 clinical trial for a licensed product. The Company has determined that the most likely amount is $15.0 million, however, the Company will not include this $15.0 million milestone in the transaction price until it becomes probable that a significant reversal of cumulative revenue will not occur.

Additional consideration to be paid to the Company includes development and sales milestones, profit and loss share, royalties and option exercise payments. These additional payments are achievable only after the completion of the Phase 2a clinical trial under the Development Program or exercise of the license options under the Discovery Program and therefore are excluded from the transaction price. Additionally, Takeda’s equity purchase commitments of up to $20.0 million are at fair value and therefore no non-cash consideration has been included as a component of the transaction price.

The Company allocated the transaction price to the separate performance obligations based on their relative standalone selling prices. The Company determined the standalone selling price of the Development Program Performance Obligation based on the costs incurred to develop RIVAL-01 plus the estimated costs to perform the research, development and manufacturing services through the completion of the Phase 2a clinical trial, inclusive of a reasonable profit margin. The Company determined the standalone selling price of the Discovery Program Performance Obligation based on the estimated costs to discover and research four Selected Discovery Candidates, inclusive of a reasonable profit margin. Significant inputs used to determine the standalone selling prices of the performance obligations include the length of time required, the internal hours expected to be incurred on the services, and the amount of third-party expenses that will be incurred to complete the performance obligations.

The Company recognizes the amounts associated with these performance obligations on a proportional performance basis over the contract term using input-based measurements of total cost of research and development incurred to estimate the proportion performed as compared to the estimated total cost and remeasures its progress towards completion at the end of each reporting period.

As of December 31, 2021, the transaction price was updated to $192.6 million to reflect an increase in the variable consideration related to the expense sharing under the Development Program from $58.6 million at inception to $92.6 million.


Performance Obligations	Price Pre- Modification	Price at Modification
Development Program	$166.3 million	$134.3 million
Discovery Program	$26.3 million	$21.2 million
Total	$192.6 million	$155.5 million

Additionally, the Company updated its measure of progress for each performance obligation as of the modification date and recorded a cumulative adjustment that increased collaboration revenue by $31.6 million on the partially satisfied remaining performance obligations, as the remaining services to be performed under each of the performance obligations are not distinct from the services prior to the modification.

Costs incurred relating to the Takeda Agreement consist of internal and external research and development costs, which primarily include salaries and benefits, lab supplies, and preclinical research studies. All of these costs are included in research and development expenses in the Company’s consolidated statements of operations and comprehensive loss during the twelve months ended December 31, 2023 and 2022.

The deferred revenue balance in connection with the Takeda Agreement as of December 31, 2023 and 2022 was $0.0 million and $19.3 million, respectively, which is classified as either current or noncurrent in the accompanying consolidated balance sheets based on the periods the performance obligations are expected to be performed. The Company recognized the remaining deferred revenue balance during the three months ended March 31, 2023 as the Company concluded that there were no remaining estimated services to be performed associated with the obligations under the Takeda Agreement. The Company recognized collaboration revenue related to the Takeda Agreement for the twelve months ended December 31, 2023 and 2022 of $19.3 million and $73.3 million, respectively. Receivables related to reimbursable costs expected to be received from Takeda for research and development services performed under the Development Program at December 31, 2023 and 2022 were $0.2 million and $8.7 million, respectively.

H. Lee Moffitt Cancer Center

Master Collaboration Agreement

In January 2021, the Company entered into an amended and restated master collaboration agreement (the “Moffitt Agreement”), with Moffitt, to amend a then-existing master collaboration agreement from November 2019, as amended March 2020, between Moffitt and the Company’s now wholly-owned subsidiary, Myst Therapeutics LLC, with the intent to continue to work collaboratively in the research of cancer immunotherapies.

Each party granted the other party a right to use its research materials for performance of the research plans agreed to by the parties (the “Research Plans”). Each party granted the other party a non-exclusive, worldwide, sublicensable, perpetual, irrevocable, royalty-free license under all inventions invented in performance of a Research Plan and invented jointly by the Company and Moffitt (the “Joint Inventions”) (with certain exclusions) to make, use, sell, offer for sale, import products and services and/or otherwise practice such inventions.

The Company granted Moffitt a royalty free, non-sublicensable, non-transferable, perpetual, non-exclusive license to use and practice certain inventions invented solely by the Company in the performance of a Research Plan for its internal non-commercial research purposes.

Moffitt granted the Company (i) a royalty-free, sublicensable, non-transferable, perpetual, non-exclusive license to use and practice certain inventions invented solely by Moffitt in the performance of a Research Plan (“Moffitt Inventions”), (a) for internal, non-commercial research purposes outside the field of ACT and/or (b) to research, develop, make, use, sell, offer to sell, or import products and/or services in the field of ACT and (ii) a royalty free, sublicensable, non-transferable, perpetual, non-exclusive license to use and practice certain inventions invented in performance of a Research Plan or through the use of specified Moffitt research materials.

Moffitt granted the Company an option to obtain, with terms to be negotiated in good faith under commercially reasonable terms, a royalty-bearing, sublicensable exclusive license in the Moffitt Inventions, the TCR Inventions, and/or Moffitt’s interest in Joint Inventions. The Company can exercise this option at any time within six months after Moffitt informs the Company of any new invention, and upon the Company’s exercise, the parties will have a period of six months to negotiate the terms of such exclusive license.

The Moffitt Agreement will expire upon the later of (i) four years from the effective date of the Moffitt Agreement or (ii) the termination or expiration of all Research Plans in effect under the Moffitt Agreement, unless

extended upon mutual written agreement of the parties. Either party may terminate the Moffitt Agreement for cause upon any uncured breach by the other party or upon the insolvency of the other party.

Moffitt Alliance Agreement

In June 2022, the Company entered into a life science alliance agreement with Moffitt (the “Alliance Agreement”), in order to further expand the Company’s relationship and support the Company’s existing agreements with Moffitt (the “Underlying Agreements”). Pursuant to the Alliance Agreement, the Company will have priority access to Moffitt’s scientific research, manufacturing, and clinical capabilities for the development of novel TIL therapies, including expedited clinical trial activation, enhanced patient screening and data sharing, access to Moffitt’s cellular therapies research and development infrastructure, expanded molecular data sets and biospecimens for research, and allocated cGMP manufacturing capacity for the Company’s product candidates.

Under the Alliance Agreement, the Company is obligated to use commercially reasonable efforts to further develop TIL Products, to manufacture TIL Products, to obtain regulatory approval for at least one TIL Product in the United States and to commercialize TIL Products in all countries in which regulatory approval for a TIL Product has been obtained. For purposes of the Alliance Agreement, TIL Product means any pharmaceutical, biopharmaceutical, or biotechnology TIL product that has been developed by us or Moffitt and is advanced into clinical development under an IND sponsored by Moffitt.

Pursuant to the Alliance Agreement, the Company agreed to pay to Moffitt a total amount of at least $17.5 million (the “Alliance Funding Amount”), for research, development and manufacturing related services that will be paid equally over five years on June 1st of each year starting on June 1, 2023. The Alliance Funding Amount will be calculated annually at the conclusion of each payment period, and, to the extent the Company’s annual aggregate payments to Moffitt of $3.5 million exceeds the applicable annual installment amount, the Company will receive a reduction in the amount due for future installment payments based on a predetermined formula agreed to by the parties. To the extent the aggregate annual payments are less than $3.5 million, the Company will prepay the remaining amount due.

In connection with the execution of the Alliance Agreement, the Company issued Moffitt 91,721 shares of its common stock. As partial consideration under the Alliance Agreement, the Company also agreed to issue Moffitt an additional 366,884 shares of its common stock in the aggregate upon the satisfaction of certain clinical and regulatory milestones with respect to TIL Products. The issuances of common stock are treated as performance-based stock awards. On February 27, 2023, 91,721 shares were issued due to the achievement of the milestone related to the start of the Phase 1 trial. In addition, upon achievement of certain thresholds for aggregate net sales of all TIL Products, the Company is required to make tiered sales-based milestones payments to Moffitt of up to an aggregate of $50.0 million. With respect to each of the equity and sales milestones described above, TIL Products include any pharmaceutical, biopharmaceutical or biotechnology TIL Product that is developed by the Company or Moffitt and is advanced into clinical development under an IND sponsored by Moffitt.

Unless earlier terminated, the Alliance Agreement will remain in effect for a term of five years and may be extended for additional periods upon the mutual written consent of both parties. Either party may terminate the Alliance Agreement in the event of (i) the other party’s material breach of the Alliance Agreement that remains uncured after ninety days of receiving written notice of such breach (or in the case of breach of payment obligations, within ten days), (ii) the other party’s insolvency and (iii) a pandemic event resulting in government lockdowns or orders that legally compel such party to cease operations or that result in material disruptions in the available workforce and prevents such party from performing its contractual obligations for a period of more than six months. At any time after June 1, 2025, either party may terminate the Alliance Agreement without cause upon sixty days prior written notice to the other party (a “Termination for Convenience”). Upon a Termination for Convenience, the terminating party shall pay to the other party a termination fee in an amount equal to a low double digit percentage of the then remaining Alliance Funding Amount. Termination or expiry of one or more Underlying Agreements does

not affect the term of the Alliance Agreement, which will continue to apply to the remaining ongoing Underlying Agreements.

Income Taxes - Schedule of Reconciliation of the Expected Provision for Income Tax Recovery (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Income Tax Disclosure [Abstract]
Loss before income taxes	$ (55,486)	$ (30,693)
Statutory rate	21.00%	21.00%
Expected income tax recovery	$ (11,652)	$ (6,446)
Permanent differences	211	260
Foreign rate differential	(149)	(462)
Canada ITC credits	(715)	(1,617)
Federal R&D credit	(1,776)	(1,637)
Unrecognized tax benefit	(13)	22
State tax	3,348	(2,422)
Myst transaction	210	1,877
Other	1,337	(4)
Change in valuation allowance	9,525	10,570
R&D credit carryback claim	(612)
Total tax provision (benefit)	$ (286)	$ 141

Income Taxes

12 Months Ended

Dec. 31, 2023

Income Tax Disclosure [Abstract]

Income taxes

10. Income Taxes

The following table represents the components of net loss before income taxes (in thousands):


	Year Ended December 31,
	2023			2022
Domestic	$	(52,765	)	$	(22,065	)
Foreign		(2,721	)		(8,628	)
Loss before provision for income taxes	$	(55,486	)	$	(30,693	)

The income tax provision consisted of the following (in thousands):


	Year Ended December 31,
	2023			2022
Current:
Federal	$	(522	)	$	80
State taxes		236			61
Deferred:
Federal					—
State					—
Total tax provision (benefit)	$	(286	)	$	141

The reconciliation of the expected provision for income tax recovery to the actual provision for income tax expense reported is as follows (in thousands):


	Year Ended December 31,
	2023			2022
Loss before income taxes	$	(55,486	)	$	(30,693	)
Statutory rate		21	%		21	%
Expected income tax recovery		(11,652	)		(6,446	)
Permanent differences		211			260
Foreign rate differential		(149	)		(462	)
Canada ITC credits		(715	)		(1,617	)
Federal R&D credit		(1,776	)		(1,637	)
Unrecognized tax benefit		(13	)		22
State tax		3,348			(2,422	)
Myst transaction		210			1,877
Other		1,337			(4	)
Change in valuation allowance		9,525			10,570
R&D credit carryback claim		(612	)		—
Provision for income taxes (benefit) expenses	$	(286	)	$	141

The significant components of the Company’s deferred income tax assets are as follows (in thousands):


	Year Ended December 31,
	2023			2022
Deferred tax assets:
Credits	$	10,874		$	7,960
Accruals		125			108
Stock compensation		898			1,111
State taxes		1			33
Right-of-use lease liability		680			1,319
Property and equipment		—			144
Intangibles		20,726			16,858
Tax losses		14,783			7,253
Deferred revenue		—			5,290
Total deferred tax assets	$	48,087		$	40,076
Deferred tax liability:
Right-of-use lease asset	$	(588	)	$	(1,174	)
Property and equipment		(734	)		(1,665	)
Unrealized gains/losses		(3	)		—
Total deferred tax liability	$	(1,325	)	$	(2,839	)
Valuation allowance		(46,762	)		(37,237	)
Net deferred tax assets	$	0		$	0

As of December 31, 2023, the Company had approximately $39.7 million of U.S. federal and $9.3 million of state net operating loss, or NOL, carryforwards. The Company’s U.S. federal NOL carryforwards can be carried forward indefinitely, but use of such carryforwards is limited to 80% of taxable income. If not utilized, the Company’s state NOL carryforwards will begin to expire at various dates beginning in 2038.

Furthermore, under Section 382 of the Internal Revenue Code of 1986, the amount of benefits from the Company’s NOL carryforwards may be impaired or limited if we incur a cumulative ownership change of more than 50% over a three-year period. The Company has not conducted an analysis as to whether such a change of ownership has occurred, but if such a change has occurred or occurs in the future, the Company will be limited regarding the amount of NOL carryforwards that can be utilized annually in the future to offset taxable income. Any such annual limitation may significantly reduce the value of the Company’s NOL carryforwards before they expire, which could result in greater tax liabilities than the Company would incur in the absence of such a limitation.

The Company has determined that it is not more likely than not that it will realize all of its deferred tax assets, and therefore a valuation allowance has been established against the deferred tax assets for Canadian and U.S. State jurisdictions. The Company files federal and provincial income tax returns in Canada and federal, state and local U.S. Income tax returns.

For the Canadian Entity the Company estimates SR&ED expenditures and claims investment tax credits for income tax purposes based on management’s interpretation of the applicable legislation in the Income Tax Act (the “Act”) and related provincial legislation. These claims are subject to audit by the tax authorities. In the opinion of management, the treatment of research and development expenditures for income tax purposes is appropriate. Any difference between recorded refundable tax credits and amounts ultimately received is recorded when the amount becomes known.

In the ordinary course of its business for the U.S. entity, the Company incurs costs that, for tax purposes, are determined to be qualified research expenditures within the meaning of IRC §41 and are, therefore, eligible for the Increasing Research Activities credit under IRC §41. The federal Research and Development credit (“R&D Credit”) carryforward as of December 31, 2023 is $5.0 million that will expire in 2039, and the California R&D credit carryforward of $2.3 million as of December 31, 2023 has no expiration date.

As of December 31, 2023, the Company has total uncertain tax benefits of $2.2 million related to the R&D credit, of which $1.9 million is recorded as a reduction of the deferred tax asset related credit carryforward. If the uncertain tax benefits were to be recognized, there would be an impact to the effective tax rate. No interest or penalties have been recorded related to the uncertain tax positions. However, the impact would be immaterial. The Company’s policy is to include interest and penalties related to uncertain tax benefits as other expense.

The aggregate changes in the balances of the Company’s gross unrecognized tax benefits during 2023 were as follows (in thousands):


December 31, 2022	$	(857	)
Increases in balances related to tax positions taken during a prior period		(541	)
Increases in balances related to tax positions taken during the current period		(799	)
Decreases in balances related to tax positions tax during the prior period		—
December 31, 2023	$	(2,197	)

It is not expected that there will be a significant change in uncertain tax position in the next 12 months.

The Company is subject to U.S. federal and state income tax as well as to income tax in multiple state jurisdictions. In the normal course of business, the Company is subject to examination by tax authorities. As of the date of the consolidated financial statements, there are no tax examinations in progress. The statute of limitations for tax years ended after December 31, 2020 are open for state and federal tax purposes.

At December 31, 2023, the Canadian Entity had carryforward balances which are available to offset future years’ taxable income. At December 31, 2023, the Company had non-refundable investment tax credits amounting to $7.6 million that begin to expire in 2038 and an SR&ED expenditure pool of $21.9 million that does not expire. During 2023, the Company expects to utilize $0.0 million of non-capital losses and $0.5 million of investment tax credits to offset its 2023 Canada tax liability.

On June 29, 2020, the California governor signed Assembly Bill 85 (“A.B. 85”), which includes several tax measures to close a gap in the budget created by the COVID-19 pandemic. The most significant provisions of the bill are (i) the suspension of taxpayers’ ability to deduct net operating losses during tax years 2020, 2021, and 2022; and (ii) the limitation on the amount of tax that can be offset by business credits to $5 million for tax years 2020, 2021, and 2022. For corporate taxpayers, if their income subject to California taxation is less than $1.0 million the suspension does not apply. On February 9, 2022, the California Governor signed Senate Bill 113 “SB 113”. SB 113 which removes the suspension of NOL and the limitation on the amount of tax that can be offset by business credits to $5.0 million provisions included in A.B. 85 for the 2022 tax year. Thus, the Company is not expecting its net operating loss carryover to be limited for the tax year ending December 31, 2022.

- Definition

The entire disclosure for income taxes. Disclosures may include net deferred tax liability or asset recognized in an enterprise's statement of financial position, net change during the year in the total valuation allowance, approximate tax effect of each type of temporary difference and carryforward that gives rise to a significant portion of deferred tax liabilities and deferred tax assets, utilization of a tax carryback, and tax uncertainties information.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480990/946-20-50-13

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 235
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(h)(2))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480678/235-10-S99-1

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-Name Accounting Standards Codification
-Publisher FASB
-URI https://asc.fasb.org//740/tableOfContent

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 14
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482685/740-10-50-14

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 21
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482685/740-10-50-21

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 270
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482526/740-270-50-1

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 17
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482685/740-10-50-17

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SAB TOPIC 6.I.5.Q1)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479360/740-10-S99-1

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 2
-Subparagraph (SAB Topic 11.C)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479360/740-10-S99-2

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482603/740-30-50-2

+ Details

Leases - Schedule of Information about Lease Costs (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Lease, Cost [Abstract]
Operating lease cost	$ 2,074	$ 1,956
Short-term lease costs	4	263
Variable leases costs	5	52
Sublease income	(477)	(21)
Total lease cost	$ 1,606	$ 2,250

Equity Based Compensation (Tables)

12 Months Ended

Dec. 31, 2023

Share-Based Payment Arrangement [Abstract]

Schedule of stock option plan activity

A summary of the stock option activity under the Plans is as follows:


	Number of Shares Underlying Outstanding Options			Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Term (Years)		Aggregate Intrinsic Value (in thousands)
Outstanding — December 31, 2021		1,759,275		$	7.26		7.2	$	6,912
Options granted		951,543		$	11.02
Options exercised		(61,355	)	$	2.55
Options canceled/forfeited		(119,481	)	$	5.75
Outstanding — December 31, 2022		2,529,982		$	8.86		6.8	$	5,886
Options granted		1,028,355		$	5.44
Options exercised		(29,715	)	$	3.49
Options canceled/forfeited		(154,340	)	$	10.29
Outstanding — December 31, 2023		3,374,282		$	7.66		7.1	$	352
Exercisable — December 31, 2023		1,792,591		$	7.93		5.3	$	347
Vested and expected to vest — December 31, 2023		3,374,282		$	7.66		7.1	$	352

Schedule of fair value assumption of stock option activity

The fair value of each stock option granted to employees and directors was estimated on the date of grant using the Black-Scholes option-pricing model, with the following range of assumptions:


	Year Ended December 31,
	2023	2022
Risk-free interest rate	3.9% - 4.8%	1.7% - 3.6%
Expected term (in years)	5.8 - 6.2	5.7 - 6.0
Dividend yield	0.0%	0.0%
Volatility	85.8% - 88.2%	86.3% - 87.2%
Weighted-average exercise price of stock options granted	$5.44	$11.02

Summary of RSU activity

As of December 2023, the Company grants RSUs to employees. The RSU activity is summarized as follows:


	Number of RSUs		Weighted- Average Grant Date Fair Value
Outstanding, non-vested as of December 31, 2022		—	$	—
Granted		102,945	$	2.71
Cancelled/Forfeited		—		—
Vested/Released		—		—
Outstanding, non-vested as of December 31, 2023		102,945	$	2.71

Schedule of stock based compensation for stock awards

The allocation of stock-based compensation expense for all stock awards, including options, restricted stock and RSUs, included in the Company’s statements of operations is as follows (in thousands):


	Year Ended December 31,
	2023		2022
Research and development	$	2,274	$	2,167
General and administrative		1,942		2,201
Total stock-based compensation	$	4,216	$	4,368

Property and Equipment, Net - Schedule of Property and Equipment, Net Consist (Detail) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Property, Plant and Equipment [Line Items]
Computer equipment and software		$ 376
Laboratory equipment	$ 11,043	12,901
Furniture	690	758
Leasehold improvements	1,308	1,308
Property plant and equipment gross	13,041	15,343
Less: Accumulated depreciation and amortization	(6,689)	(5,619)
Total property and equipment, net	$ 6,352	$ 9,724

Asset Acquisition

12 Months Ended

Dec. 31, 2023

Asset Acquisition [Abstract]

Asset Acquisition

7. Asset Acquisition

In December 2020, the Company entered into the Agreement and Plan of Merger and Reorganization (the “Myst Merger Agreement”), by and among the Company, Flatiron Merger Sub I, Inc. (“Merger Sub”), Flatiron Merger Sub II, LLC (“Merger LLC”), a direct, wholly-owned subsidiary of the Company, Myst Therapeutics, Inc. (“Myst”), and Timothy Langer, the sole common stockholder of Myst (“Langer”). Pursuant to the Myst Merger Agreement, the business combination (the “Merger”) was affected in two steps. The first step was the merger of Merger Sub with and into Myst. The second step was the merger of Myst with and into Merger LLC. The Merger closed on December 14, 2020, and the effective date of the Merger was January 20, 2021. As a result of the Merger, the separate existences of Merger Sub and Myst ceased, and Merger LLC became the Company’s wholly-owned subsidiary.

Pursuant to the Myst Merger Agreement, on December 15, 2020, the Company paid the former equity holders of Myst, (the “Myst Holders”), a one-time up-front payment of $9.0 million in cash. The Company paid an additional cash consideration of $1.0 million to the Myst Holders on June 14, 2022. The Company also issued Langer up to 725,920 shares of the Company’s common stock. Of these shares, 362,960 shares of the Company’s common stock were issued upon the closing of the Merger and the remaining 362,960 shares of the Company’s common stock were held in escrow with 25% vesting in December of each year that Langer remains an employee of the Company. As of December 31, 2023, Langer is still employed by the Company and 272,220 shares of the Company’s common stock have vested and been released from escrow with the remaining 90,740 shares of the Company’s common stock to be released in December 2024, based on his continued employment. This restricted equity grant is accounted for as a compensatory arrangement under ASC 718 as continued service is required under the agreement. fo

In addition, under the Myst Merger Agreement, each Myst Holder is entitled to receive certain payments as consideration based on the achievement by the Company of three predefined milestones. The initial milestone is the closing of an initial public offering, which occurred on July 25, 2023, the second milestone is the first acceptance by the FDA of an IND filed by, on behalf of or for the benefit of the Company, or the Company’s sublicensees for a product being developed by or on behalf of the Company or its sublicensees that is claimed as a product or method of making or using the product by a pending or issued Myst patent claim existing at the time of such acceptance, and the third milestone is the occurrence of the earlier of (i) the commencement of the first registration study for a product being developed by, on behalf of or for the benefit of the Company that is claimed as a product or a method of making or using the product by an issued Myst patent claim existing as of the time of such commencement or (ii) the issuance of a Myst patent claim that claims a product or method of making or using the product then being developed by, on behalf of or for the benefit of the Company, or its sublicensees, that is or was the subject of a registration study that has or had commenced. The milestones are not contingent on one another, and the milestones do not need to be achieved in any specific order.

Within 45 days of the achievement of the initial milestone, which occurred on July 25, 2023, the Company is obligated to pay the Myst Holders an aggregate amount equal to $3.0 million. At the Company’s election, the Company may pay this consideration in cash or in shares of the Company’s common stock. Pursuant to a letter agreement dated September 11, 2023 between the Company and the former equityholders of Myst regarding the $3.0 million milestone payment that became due and owing to the Myst Holders, the Company agreed to pay $0.2 million in cash to the former optionholders of Myst on or before September 30, 2023, with the remaining $2.8 million payable to Langer in shares of the Company’s common stock. On September 11, 2023, the Company issued 249,992 shares of the Company’s common stock to Langer.

Within 45 days of the achievement of the second milestone, the Company is obligated to pay the Myst Holders an aggregate amount equal to $10.0 million. At the Company’s election, the Company may pay this consideration in cash or in shares of the Company’s common stock. In May 2022, this $10.0 million milestone was achieved. The Company elected to pay $5.0 million in the Company’s common stock and $5.0 million in cash. Pursuant to a letter agreement dated July 25, 2022 between the Company and the former equityholders of Myst regarding the $10.0 million milestone payment that became due and owing to the Myst Holders, the Company

agreed to pay to the former optionholders of Myst on or before July 28, 2022, $0.6 million in cash, with the remaining $9.4 million payable to Langer as follows: (i) on or before July 28, 2022, $2.2 million in cash, (ii) on or before July 31, 2022, $5.0 million in shares of the Company’s common stock and (iii) on or before January 10, 2023, $2.2 million in cash. On June 8, 2022, the Company issued Langer 212,203 shares of the Company’s common stock to settle the $5.0 million obligation payable in common stock. The Company then paid the Myst Holders $2.8 million in July 2022, with $2.2 million paid to Langer and $0.6 million paid to the remaining Myst Holders, and the remaining $2.2 million was paid to Langer in January 2023.

Within 45 days of the achievement of the third milestone, the Company is obligated to pay the Myst Holders an aggregate amount equal to $20.0 million. At the Company’s election, the Company may pay this consideration in cash or in shares of its common stock.

The Company accounted for the merger with Myst pursuant to the Myst Merger Agreement as an asset acquisition as substantially all of the value received was concentrated in the acquired in-process research and development of Myst and did not have an alternate future use. The Company recognized a $19.4 million charge to research and development expense at the time of the completion of the asset acquisition during the year ended December 31, 2020. The Company determined that the milestone payments are separate units of account and accounted for the initial milestone as a derivative in accordance with ASC 815 and the second and third milestones as liabilities in accordance with ASC 480. In connection with the initial public offering, the Company reassessed its initial accounting of the milestone payments and concluded that they should be viewed as one unit of account because the milestone payments are not legally detachable from each other. The milestone payments, as one unit of account, would be classified as a liability in accordance with ASC 480 and measured at fair value, with changes in the fair value recorded in earnings. Regardless of whether the milestone payments are viewed as one unit of account or three units of account, because they are all subject to fair value measurement, the financial reporting effect of the contingent consideration arrangement as one unit of account or three units of account is substantially the same. As a liability under ASC 480, the contingent consideration will continue to be recorded at fair value until settled. The adjustment to the fair value of the contingent consideration of $0.9 million and $7.0 million for the twelve months ended December 31, 2023 and 2022, respectively were included in research and development expense in the Company’s consolidated statements of operations and comprehensive loss.

Redeemable Convertible Preferred Stock and Stockholders' Equity

12 Months Ended

Dec. 31, 2023

Stockholders' Equity Note [Abstract]

Redeemable Convertible Preferred Stock and Stockholders' Equity

8. Redeemable Convertible Preferred Stock and Stockholders’ Equity

Redeemable Convertible Preferred Stock

From October 2015 to October 2016, the Company issued a total of 11,250,000 shares of series A preferred stock (the “Series A Preferred Stock”) at CDN$1.00 per share (equivalent to $0.74 per share, based on a conversion ratio of 1.344 Canadian dollars to one U.S. dollar) for total net proceeds of CDN$ 10.9 million (equivalent to $8.1 million based on a conversion ratio of 1.344 Canadian dollars to one U.S. dollar).

In October 2016, the Company issued a total of 16,285,156 shares of series B-1 preferred stock (the “Series B-1 Preferred Stock”) at $0.77 per share for total net proceeds of $12.3 million. In November 2018, the Company issued 25,065,538 shares of series B-2 preferred stock (the “Series B-2 Preferred Stock”, and together with the Series B-1 Preferred Stock, the “Series B Preferred Stock”) at $1.15 per share for total net proceeds of $28.9 million.

The Company issued a total of 17,905,288 shares of series C preferred stock (the “Series C Preferred Stock”) at $2.35 per share in January 2019 for net proceeds of $41.8 million.

The Company issued a total of 29,285,356 shares of series D preferred stock (the “Series D Preferred Stock”) at $2.73 per share in June 2021 for net proceeds of $79.8 million.

In connection with the Company's IPO, all outstanding shares of the Company's redeemable convertible preferred stock automatically converted into 12,493,879 shares of common stock. Subsequent to the closing of the IPO, there were no shares of redeemable convertible preferred stock outstanding.

Common Stock

In connection with the closing of the IPO, the Company filed its Amended and Restated Certificate of Incorporation which provides that the authorized common stock of the Company is 490,000,000 shares of common stock with a par value of $0.001 per share. Holders of outstanding shares of common stock are entitled to one vote for each share held of record on all matters submitted to a vote of the holders of common stock. Subject to the rights of the holders of any class of the Company’s capital stock having any preference or priority over common stock, the holders of common stock are entitled to receive dividends that are declared by the Company’s board of directors out of legally available funds. In the event of a liquidation, dissolution or winding-up, the holders of common stock are entitled to share ratably in the net assets remaining after payment of liabilities, subject to prior rights of preferred stock, if any, then outstanding. The common stock has no preemptive rights, conversion rights, redemption rights or sinking fund provisions, and there are no dividends in arrears or default. All shares of common stock have equal distribution, liquidation and voting rights, and have no preferences or exchange rights.

Shares of common stock reserved for future issuance, on an as-if-converted basis, consisted of the following:


	December 31,		December 31,
	2023		2022
Series A redeemable convertible preferred stock		—		1,408,502
Series B-1 redeemable convertible preferred stock		—		2,038,903
Series B-2 redeemable convertible preferred stock		—		3,138,208
Series C redeemable convertible preferred stock		—		2,241,740
Series D redeemable convertible preferred stock		—		3,666,526
Common stock options outstanding		3,374,282		2,529,982
Unvested RSUs		102,945		—
Shares available for issuance under the ESPP		222,287		—
Shares available for issuance under the Plans		1,755,404		255,685
		5,454,918		15,279,546

- Definition

The entire disclosure for equity.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481112/505-10-50-13

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Subparagraph (h)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481112/505-10-50-13

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 14
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481112/505-10-50-14

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 235
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481062/946-235-50-2

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 235
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481062/946-235-50-2

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 505
-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481004/946-505-50-6

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 815
-SubTopic 40
-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Subparagraph (a)
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-URI https://asc.fasb.org//1943274/2147480237/815-40-50-6

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480008/505-10-S99-1

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 235
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-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(e)(1))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480678/235-10-S99-1

Reference 10: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 505
-Name Accounting Standards Codification
-Publisher FASB
-URI https://asc.fasb.org//505/tableOfContent

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
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-Section 50
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-URI https://asc.fasb.org//1943274/2147481112/505-10-50-13

Reference 12: http://www.xbrl.org/2003/role/disclosureRef
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Reference 13: http://www.xbrl.org/2003/role/disclosureRef
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Reference 14: http://www.xbrl.org/2003/role/disclosureRef
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-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481112/505-10-50-18

Reference 18: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 18
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481112/505-10-50-18

Reference 19: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 18
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481112/505-10-50-18

+ Details

Property and Equipment, Net (Tables)

12 Months Ended

Dec. 31, 2023

Property, Plant and Equipment [Abstract]

Schedule of Property and Equipment Net

Property and equipment, net consist of the following (in thousands):


	December 31,			December 31,
	2023			2022
Computer equipment and software	$	—		$	376
Laboratory equipment		11,043			12,901
Furniture		690			758
Leasehold improvements		1,308			1,308
		13,041			15,343
Less: Accumulated depreciation and amortization		(6,689	)		(5,619	)
Total property and equipment, net	$	6,352		$	9,724

Equity Based Compensation - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended		12 Months Ended
	Jul. 31, 2023	Dec. 31, 2020	Dec. 31, 2023	Dec. 31, 2022
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Allocated share based compensation expense			$ 4,216	$ 4,368
Share-based compensation arrangement by share-based payment award, options, grants in period, weighted average grant date fair value			$ 4.06	$ 7.91
Total weighted-average grant date fair value of RSUs granted			$ 300
Common Stock, Capital Shares Reserved for Future Issuance			5,454,918	15,279,546
Stock option member
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share-based payment arrangement, nonvested award, cost not yet recognized			$ 7,000
Share-based payment arrangement, non-vested award, cost not yet recognized, period for recognition			3 years
RSUs [Member]
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total grant date fair value of RSUs granted			$ 2.71
Share-based payment arrangement, nonvested award, cost not yet recognized			$ 300
Share-based payment arrangement, non-vested award, cost not yet recognized, period for recognition			3 years 10 months 24 days
Share-based compensation arrangement by share-based payment award, equity instruments other than options, nonvested, number			102,945
Myst Merger Agreement [Member] \| Restricted Stock [Member]
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Award requisite service period		4 years
Share-based payment arrangement, non-vested award, cost not yet recognized, period for recognition			1 year
Share-based compensation arrangement by share-based payment award, equity instruments other than options, nonvested, number			90,740
Share-based payment arrangement, non-vested award, excluding option, cost not yet recognized, amount			$ 900
Myst Merger Agreement [Member] \| Timothy Langer [Member]
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Business acquisition, equity interest issued or issuable, number of shares		725,920
Myst Merger Agreement [Member] \| Timothy Langer [Member] \| Restricted Stock [Member]
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Business acquisition, equity interest issued or issuable, number of shares		362,960
2018 Plan [Member]
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Award requisite service period			10 years
Award vesting period			4 years
Share-based compensation arrangement by share-based payment award, award vesting rights, percentage			25.00%
2023 Plan [Member]
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Award vesting period			4 years
Maximum term of options issued under equity incentive plan			10 years
Common stock, capital shares reserved for future issuance increase decrease period	10 years
Share-based compensation arrangement by share-based payment award, percentage of outstanding stock maximum	5.00%
2023 Plan [Member] \| New Shares Under 2023 [Member]
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share-based compensation arrangement by share-based payment award, number of shares available for grant	1,889,435
2023 Plan [Member] \| Remaining Shares From 2018 Plan [Member]
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share-based compensation arrangement by share-based payment award, number of shares available for grant	712,503
2023 Plan [Member] \| Returning Shares [Member]
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share-based compensation arrangement by share-based payment award, number of shares available for grant	120,949
Employee Stock Purchase Plan [Member]
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Number of shares authorized for issuance under share-based payment arrangement	222,287
Common Stock, Capital Shares Reserved for Future Issuance	666,680
Common stock, capital shares reserved for future issuance increase decrease period	10 years
Share-based compensation arrangement by share-based payment award, percentage of outstanding stock maximum	1.00%

Redeemable Convertible Preferred Stock and Stockholders' Equity (Tables)

12 Months Ended

Dec. 31, 2023

Stockholders' Equity Note [Abstract]

Summary of shares of common stock reserved for future issuance

Shares of common stock reserved for future issuance, on an as-if-converted basis, consisted of the following:


	December 31,		December 31,
	2023		2022
Series A redeemable convertible preferred stock		—		1,408,502
Series B-1 redeemable convertible preferred stock		—		2,038,903
Series B-2 redeemable convertible preferred stock		—		3,138,208
Series C redeemable convertible preferred stock		—		2,241,740
Series D redeemable convertible preferred stock		—		3,666,526
Common stock options outstanding		3,374,282		2,529,982
Unvested RSUs		102,945		—
Shares available for issuance under the ESPP		222,287		—
Shares available for issuance under the Plans		1,755,404		255,685
		5,454,918		15,279,546

Agreements - Schedule of Transaction Price Allocated to Programs Performance Obligation (Detail) $ in Millions	Jun. 30, 2022 USD ($)
Price Pre-Modification [Member]
Schedule Of Transaction Price Allocatied To Programs Performance Obligation [Line Items]
Performance Obligations	$ 192.6
Price at Modification [Member]
Schedule Of Transaction Price Allocatied To Programs Performance Obligation [Line Items]
Performance Obligations	155.5
Development Program [Member] \| Price Pre-Modification [Member]
Schedule Of Transaction Price Allocatied To Programs Performance Obligation [Line Items]
Performance Obligations	166.3
Development Program [Member] \| Price at Modification [Member]
Schedule Of Transaction Price Allocatied To Programs Performance Obligation [Line Items]
Performance Obligations	134.3
Discovery Program [Member] \| Price Pre-Modification [Member]
Schedule Of Transaction Price Allocatied To Programs Performance Obligation [Line Items]
Performance Obligations	26.3
Discovery Program [Member] \| Price at Modification [Member]
Schedule Of Transaction Price Allocatied To Programs Performance Obligation [Line Items]
Performance Obligations	$ 21.2

Fair Value of Financial Assets and Liabilities - Schedule of company's cash, cash equivalents and available-for-sale securities (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Fair Value Disclosures [Line Items]
Amortized cost	$ 92,626	$ 57,140
Gross unrealized gains	104
Gross unrealized losses		(190)
Estimated fair value	92,730	56,950
Money market funds [Member] \| Level 1 [Member]
Fair Value Disclosures [Line Items]
Amortized cost	15,635	9,238
Estimated fair value	15,635	9,238
Restricted cash [Member]
Fair Value Disclosures [Line Items]
Estimated fair value	116	382
Restricted cash [Member] \| Level 1 [Member]
Fair Value Disclosures [Line Items]
Amortized cost	116	382
Estimated fair value	116	382
U.S. government and agency securities [Member] \| Level 1 [Member]
Fair Value Disclosures [Line Items]
Amortized cost	76,875	30,761
Gross unrealized gains	104
Gross unrealized losses		(112)
Estimated fair value	76,979	30,649
U.S. government and agency securities [Member] \| Level 2 [Member]
Fair Value Disclosures [Line Items]
Amortized cost		16,759
Gross unrealized losses		(78)
Estimated fair value		16,681
Cash and cash equivalents [Member]
Fair Value Disclosures [Line Items]
Estimated fair value	15,635	9,238
Short-term investments [Member]
Fair Value Disclosures [Line Items]
Estimated fair value	$ 76,979	$ 47,330

Property and Equipment, Net - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Property, Plant and Equipment [Abstract]
Property and equipment depreciation and amortization expense	$ 2,800	$ 2,200
Gain (loss) on disposal of property and equipment	(324)	100
Property and equipment carrying value not recoverable	7,900
Impairment charges	$ 1,582	$ 497

Equity Based Compensation

12 Months Ended

Dec. 31, 2023

Share-Based Payment Arrangement [Abstract]

Equity Based Compensation

9. Equity Based Compensation

2018 Equity Incentive Plan

In December 2018, the Company adopted the 2018 Equity Incentive Plan (the “2018 Plan”) which provided for the Company to grant incentive stock options or nonqualified stock options for the purchase of common stock, or restricted shares, to employees, members of the board of directors and consultants of the Company. The Company assumed all of the outstanding options under the amended and restated Equity Incentive Plan of Turnstone Biologics Inc. dated October 1, 2016 (the “2016 Plan”) in connection with the corporate reorganization in December 2018. However, there were no changes to the terms of the options requiring modification accounting.

All options granted under the 2018 Plan have an exercise price, a vesting period determine by the Company’s board of directors and ten-year term as determined and approved by the Company’s board of directors (the board of directors may delegate authority to one of the boards’ committees) at the time of grant. The terms and conditions of the restricted shares are determined by the board of directors at the grant date.

The majority of grants outstanding were approved with a four-year vesting schedule with 25% vesting after one year and the remainder vesting evenly over the remaining 36 months. Upon the effectiveness of the 2023 Plan defined and described below, no further grants will be made under the 2018 Plan. Any outstanding awards granted under these plans will remain subject to the terms of their 2016 and 2018 Plans, respectively, and applicable award agreements.

2023 Equity Incentive Plan

In July 2023, the Company's board of directors and stockholders adopted the 2023 Equity Incentive Plan (the “2023 Plan” and together with the 2018 and 2016 Plans the "Plans") which became effective upon the date of the IPO. Under the 2023 Plan, the Company may grant stock options, stock appreciation rights, restricted stock, RSUs,

performance stock awards, performance cash awards and other forms of stock awards to employees, directors and consultants. The maximum term of the stock option grants under the 2023 Plan is ten years. In general, the awards granted under the 2023 Plan vest over a four-year period from the vesting commencement date. The 2023 Plan does not permit early exercises. The number of shares available for future issuance under the 2023 Plan is the sum of (1) 1,889,435 new shares, plus (2) 712,503 remaining shares of common stock reserved under the 2018 Plan that became available for issuance upon the effectiveness of the 2023 Plan, and (3) up to 120,949 Returning Shares (as defined in the 2023 Plan), as such shares become available from time to time. The number of shares of common stock reserved for issuance under the 2023 Plan will automatically increase on January 1 of each year, for a period of ten years, from January 1, 2024 continuing through January 1, 2033, by 5% of the total number of shares of common stock outstanding on December 31 of the preceding calendar year, or a lesser number of shares as may be determined by the Company’s board of directors. There was no limitation for 2024. Following the effectiveness of the 2023 Plan, no further grants may be made under the 2018 Plan; however, any outstanding equity awards granted under the 2018 Plan will continue to be governed by the terms of the Plan.

A summary of the stock option activity under the Plans is as follows:


	Number of Shares Underlying Outstanding Options			Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Term (Years)		Aggregate Intrinsic Value (in thousands)
Outstanding — December 31, 2021		1,759,275		$	7.26		7.2	$	6,912
Options granted		951,543		$	11.02
Options exercised		(61,355	)	$	2.55
Options canceled/forfeited		(119,481	)	$	5.75
Outstanding — December 31, 2022		2,529,982		$	8.86		6.8	$	5,886
Options granted		1,028,355		$	5.44
Options exercised		(29,715	)	$	3.49
Options canceled/forfeited		(154,340	)	$	10.29
Outstanding — December 31, 2023		3,374,282		$	7.66		7.1	$	352
Exercisable — December 31, 2023		1,792,591		$	7.93		5.3	$	347
Vested and expected to vest — December 31, 2023		3,374,282		$	7.66		7.1	$	352

The fair value of each stock option granted to employees and directors was estimated on the date of grant using the Black-Scholes option-pricing model, with the following range of assumptions:


	Year Ended December 31,
	2023	2022
Risk-free interest rate	3.9% - 4.8%	1.7% - 3.6%
Expected term (in years)	5.8 - 6.2	5.7 - 6.0
Dividend yield	0.0%	0.0%
Volatility	85.8% - 88.2%	86.3% - 87.2%
Weighted-average exercise price of stock options granted	$5.44	$11.02

As of December 2023, the Company grants RSUs to employees. The RSU activity is summarized as follows:


	Number of RSUs		Weighted- Average Grant Date Fair Value
Outstanding, non-vested as of December 31, 2022		—	$	—
Granted		102,945	$	2.71
Cancelled/Forfeited		—		—
Vested/Released		—		—
Outstanding, non-vested as of December 31, 2023		102,945	$	2.71


	Year Ended December 31,
	2023		2022
Research and development	$	2,274	$	2,167
General and administrative		1,942		2,201
Total stock-based compensation	$	4,216	$	4,368

The weighted-average grant date Black Scholes fair market value of options granted to employees, directors and consultants during the twelve months ended December 31, 2023 and 2022 was $4.06 per share and $7.91 per share, respectively. The total weighted-average grant date fair value of RSUs granted by the Company during the year ended December 31, 2023 was $0.3 million.

As of December 31, 2023, the Company had unrecognized stock-based compensation expense of $7.0 million and $0.3 million, related to stock options and RSUs respectively, which is expected to be recognized over a weighted-average period of 3.0 years and 3.9 years, respectively.

Restricted Stock

In December 2020, Langer received 725,920 shares as payment related to the Myst Merger Agreement. Of the total issued, the Company restricted 362,960 shares to vest over a four-year period in equal annual installments. As of December 31, 2023, 90,740 shares remain unvested, and the Company had $0.9 million in unrecognized stock-based compensation expense related to unvested restricted stock which is expected to be recognized evenly over 1 year.

2023 Employee Stock Purchase Plan

In July 2023, the Company adopted the Employee Stock Purchase Plan (the “ESPP”), which became effective with the IPO on July 25, 2023. The ESPP was adopted by the Company’s board of directors and stockholders in June 2023. The ESPP initially provides participating employees with the opportunity to purchase up to an aggregate of 222,287 shares of common stock. The number of shares of common stock reserved for issuance will automatically increase on January 1st of each calendar year for a period of up to ten years, commencing on January 1, 2024 and ending on (and including) January 1, 2033, in an amount equal to the lesser of (i) one percent (1%) of the total number of shares of capital stock outstanding on the last day of the calendar month before the date of the automatic increase, and (ii) 666,680 shares of common stock. Notwithstanding the foregoing, the board may act prior to the first day of any calendar year to provide that there will be no January 1st increase in the share reserve for such calendar year or that the increase in the share reserve for such calendar year will be a lesser number of shares of common stock than would otherwise occur pursuant to the preceding sentence. There was no limitation for 2024. As of December 31, 2023, there was no enrollment offered to the Company's employees.