Voyager Therapeutics (VYGR) 10-Q 6 Aug 24 2024 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2024	Aug. 01, 2024
Document and Entity Information
Document Type	10-Q
Document Quarterly Report	true
Document Transition Report	false
Document Period End Date	Jun. 30, 2024
Entity File Number	001-37625
Entity Registrant Name	Voyager Therapeutics, Inc.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	46-3003182
Entity Address, Address Line One	75 Hayden Avenue
Entity Address, City or Town	Lexington
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	02421
City Area Code	857
Local Phone Number	259-5340
Title of 12(b) Security	Common Stock, $0.001 par value
Trading Symbol	VYGR
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Central Index Key	0001640266
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	Q2
Entity Common Stock, Shares Outstanding		54,533,254

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Current assets:
Cash and cash equivalents	$ 76,127	$ 68,802
Marketable securities, current	294,894	162,073
Accounts receivable	1,702	80,150
Related party collaboration receivable	1,549	3,341
Prepaid expenses and other current assets	7,298	5,318
Total current assets	381,570	319,684
Property and equipment, net	16,267	16,494
Deposits and other non-current assets	2,874	1,593
Operating lease, right-of-use assets	35,514	13,510
Total assets	436,225	351,281
Current liabilities:
Accounts payable	2,605	1,604
Accrued expenses	10,273	16,823
Other current liabilities	6,736	3,200
Deferred revenue, current	20,516	42,881
Total current liabilities	40,130	64,508
Deferred revenue, non-current	19,473	32,359
Other non-current liabilities	41,205	18,094
Total liabilities	100,808	114,961
Commitments and contingencies (see note 7)
Stockholders' equity:
Preferred stock, $0.001 par value: 5,000,000 shares authorized at June 30, 2024 and December 31, 2023; no shares issued and outstanding at June 30, 2024 and December 31, 2023
Common stock, $0.001 par value: 120,000,000 shares authorized at June 30, 2024 and December 31, 2023; 54,472,113 and 44,038,333 shares issued and outstanding at June 30, 2024 and December 31, 2023, respectively	54	44
Additional paid-in capital	618,538	497,506
Accumulated other comprehensive loss	(522)	(48)
Accumulated deficit	(282,653)	(261,182)
Total stockholders' equity	335,417	236,320
Total liabilities and stockholders' equity	$ 436,225	$ 351,281

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Jun. 30, 2024	Dec. 31, 2023
Condensed Consolidated Balance Sheets
Preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock shares authorized	120,000,000	120,000,000
Common stock shares issued	54,472,113	44,038,333
Common stock share outstanding	54,472,113	44,038,333

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations and Comprehensive (Loss) Income - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Condensed Consolidated Statements of Operations and Comprehensive (Loss) Income
Collaboration revenue	$ 29,578	$ 4,853	$ 49,094	$ 155,333
Operating expenses:
Research and development	34,452	21,985	61,544	40,553
General and administrative	10,151	8,294	18,758	17,322
Total operating expenses	44,603	30,279	80,302	57,875
Operating (loss) income	(15,025)	(25,426)	(31,208)	97,458
Other income:
Interest income	4,888	3,274	9,755	5,138
Other income	20	3	20	3
Total other income, net	4,908	3,277	9,775	5,141
(Loss) income before income taxes	(10,117)	(22,149)	(21,433)	102,599
Income tax provision	24	59	38	763
Net (loss) income	(10,141)	(22,208)	(21,471)	101,836
Other comprehensive (loss) income:
Net unrealized (loss) gain on available-for-sale securities	(16)	(1)	(474)	86
Total other comprehensive (loss) income	(16)	(1)	(474)	86
Comprehensive (loss) income	$ (10,157)	$ (22,209)	$ (21,945)	$ 101,922
Net (loss) income per share, basic	$ (0.18)	$ (0.51)	$ (0.37)	$ 2.42
Net (loss) income per share, diluted	$ (0.18)	$ (0.51)	$ (0.37)	$ 2.33
Weighted-average common shares outstanding, basic	57,721,934	43,520,137	57,419,490	42,102,101
Weighted-average common shares outstanding, diluted	57,721,934	43,520,137	57,419,490	43,770,999

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Common stock 2023 Neurocrine Collaborative Agreement	Common stock 2023 Novartis Collaboration Agreement	Common stock	Additional paid-in capital 2023 Neurocrine Collaborative Agreement	Additional paid-in capital 2023 Novartis Collaboration Agreement	Additional paid-in capital	Accumulated other comprehensive loss	Accumulated deficit	2023 Neurocrine Collaborative Agreement	2023 Novartis Collaboration Agreement	Total
Stockholders' Equity, Beginning Balance at Dec. 31, 2022			$ 38			$ 452,713	$ (219)	$ (393,512)			$ 59,020
Shares, Outstanding, Beginning Balance at Dec. 31, 2022			38,613,891
Exercises of vested stock options						185					185
Exercises of vested stock options (in shares)			51,993
Vesting of restricted stock units (in shares)			374,417
Issuance of common stock	$ 5			$ 31,116					$ 31,121
Issuance of common stock (in shares)	4,395,588
Stock based compensation expense						2,504					2,504
Unrealized gain (loss) on available-for-sale securities, net of tax							87				87
Net income (loss)								124,044			124,044
Stockholders' Equity, Ending Balance at Mar. 31, 2023			$ 43			486,518	(132)	(269,468)			216,961
Shares, Outstanding, Ending Balance at Mar. 31, 2023			43,435,889
Stockholders' Equity, Beginning Balance at Dec. 31, 2022			$ 38			452,713	(219)	(393,512)			59,020
Shares, Outstanding, Beginning Balance at Dec. 31, 2022			38,613,891
Unrealized gain (loss) on available-for-sale securities, net of tax											86
Net income (loss)											101,836
Stockholders' Equity, Ending Balance at Jun. 30, 2023			$ 44			490,791	(133)	(291,676)			199,026
Shares, Outstanding, Ending Balance at Jun. 30, 2023			43,759,409
Stockholders' Equity, Beginning Balance at Mar. 31, 2023			$ 43			486,518	(132)	(269,468)			216,961
Shares, Outstanding, Beginning Balance at Mar. 31, 2023			43,435,889
Exercises of vested stock options			$ 1			1,228					1,229
Exercises of vested stock options (in shares)			198,348
Vesting of restricted stock units (in shares)			62,828
Issuance of common stock under ESPP						418					418
Issuance of common stock under ESPP (in shares)			62,344
Stock based compensation expense						2,627					2,627
Unrealized gain (loss) on available-for-sale securities, net of tax							(1)				(1)
Net income (loss)								(22,208)			(22,208)
Stockholders' Equity, Ending Balance at Jun. 30, 2023			$ 44			490,791	(133)	(291,676)			199,026
Shares, Outstanding, Ending Balance at Jun. 30, 2023			43,759,409
Stockholders' Equity, Beginning Balance at Dec. 31, 2023			$ 44			497,506	(48)	(261,182)			236,320
Shares, Outstanding, Beginning Balance at Dec. 31, 2023			44,038,333
Exercises of vested stock options						78					78
Exercises of vested stock options (in shares)			32,500
Vesting of restricted stock units (in shares)			324,520
Issuance of common stock		$ 2			$ 19,303					$ 19,305
Issuance of common stock (in shares)		2,145,002
Issuance of common stock and pre-funded warrants in connection with underwritten public offering			$ 8			93,465					93,473
Issuance of common stock and pre-funded warrants in connection with underwritten public offering (in shares )			7,777,778
Stock based compensation expense						3,498					3,498
Unrealized gain (loss) on available-for-sale securities, net of tax							(458)				(458)
Net income (loss)								(11,330)			(11,330)
Stockholders' Equity, Ending Balance at Mar. 31, 2024			$ 54			613,850	(506)	(272,512)			340,886
Shares, Outstanding, Ending Balance at Mar. 31, 2024			54,318,133
Stockholders' Equity, Beginning Balance at Dec. 31, 2023			$ 44			497,506	(48)	(261,182)			$ 236,320
Shares, Outstanding, Beginning Balance at Dec. 31, 2023			44,038,333
Exercises of vested stock options (in shares)											58,458
Unrealized gain (loss) on available-for-sale securities, net of tax											$ (474)
Net income (loss)											(21,471)
Stockholders' Equity, Ending Balance at Jun. 30, 2024			$ 54			618,538	(522)	(282,653)			335,417
Shares, Outstanding, Ending Balance at Jun. 30, 2024			54,472,113
Stockholders' Equity, Beginning Balance at Mar. 31, 2024			$ 54			613,850	(506)	(272,512)			340,886
Shares, Outstanding, Beginning Balance at Mar. 31, 2024			54,318,133
Exercises of vested stock options						90					90
Exercises of vested stock options (in shares)			25,958
Vesting of restricted stock units (in shares)			56,549
Issuance of common stock under ESPP						639					639
Issuance of common stock under ESPP (in shares)			71,473
Stock based compensation expense						3,959					3,959
Unrealized gain (loss) on available-for-sale securities, net of tax							(16)				(16)
Net income (loss)								(10,141)			(10,141)
Stockholders' Equity, Ending Balance at Jun. 30, 2024			$ 54			$ 618,538	$ (522)	$ (282,653)			$ 335,417
Shares, Outstanding, Ending Balance at Jun. 30, 2024			54,472,113

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023
Cash flow from operating activities
Net (loss) income	$ (21,471)	$ 101,836
Adjustments to reconcile net (loss) income to net cash provided by operating activities:
Stock-based compensation expense	7,615	5,230
Depreciation	2,588	2,161
Impairment charge on leased facility	2,776
Amortization of premiums and discounts on marketable securities	(4,395)	(25)
Loss on disposal of fixed assets	286	124
Changes in operating assets and liabilities:
Accounts receivable	78,448
Related party collaboration receivable	1,792	(3,093)
Prepaid expenses and other current assets	(1,980)	(686)
Operating lease, right-of-use asset	2,432	957
Accounts payable	1,001	(907)
Accrued expenses	(6,550)	1,296
Operating lease liabilities	(104)	(1,385)
Deferred revenue	(35,251)	17,222
Net cash provided by operating activities	27,187	122,730
Cash flow from investing activities
Purchases of property and equipment	(3,108)	(1,719)
Purchases of marketable securities	(293,859)	(28,453)
Proceeds from sales and maturities of marketable securities	164,959	20,000
Net cash used in investing activities	(132,008)	(10,172)
Cash flow from financing activities
Proceeds from the exercise of stock options	168	1,414
Proceeds from the issuance of common stock in connection with the underwritten public offering	93,473
Proceeds from the issuance of common stock in connection with the 2023 Novartis Stock Purchase Agreement	19,305
Proceeds from the issuance of common stock in connection with the 2023 Neurocrine Collaboration Agreement		31,121
Proceeds from the purchase of common stock under ESPP	481	319
Net cash provided by financing activities	113,427	32,854
Net increase in cash, cash equivalents, and restricted cash	8,606	145,412
Cash, cash equivalents, and restricted cash, beginning of period	70,395	100,474
Cash, cash equivalents, and restricted cash, end of period	79,001	245,886
Supplemental disclosure of cash and non-cash activities
Capital expenditures incurred but not yet paid		$ 52
Operating lease right-of-use asset obtained in exchange for operating lease liability	$ 26,751

Nature of business

Nature of business	6 Months Ended
	Jun. 30, 2024
Nature of business
Nature of business	VOYAGER THERAPEUTICS INC. NOTE S TO UNAUDITED CONDENSED CONSOLIDATED FINANCIAL STATEMENTS 1. Nature of business Voyager Therapeutics, Inc. (the “Company”) is a biotechnology company whose mission is to leverage the power of human genetics to modify the course of and ultimately cure neurological diseases. The Company’s pipeline includes programs for Alzheimer’s disease; amyotrophic lateral sclerosis; Parkinson’s disease, and multiple other diseases of the central nervous system. Many of the Company’s programs are derived from its TRACER™ adeno-associated virus (“AAV”) capsid discovery platform, which the Company has used to generate novel capsids (“TRACER Capsids”) and identify associated receptors to potentially enable high brain penetration with genetic medicines following intravenous dosing. Some of the Company’s programs are wholly-owned, and some are advancing with licensees and collaborators including Alexion, AstraZeneca Rare Disease; Novartis Pharma AG, (“Novartis”); and Neurocrine Biosciences, Inc. (“Neurocrine”). The Company has a history of incurring annual net operating losses. As of June 30, 2024, the Company had an accumulated deficit of $282.7 million. The Company has not generated any product revenue and has financed its operations primarily through public offerings and private placements of its equity securities, funding from fees, option exercise payments, and milestone payments, and cost reimbursements associated with its prior and ongoing collaborations and license agreements. As of June 30, 2024, the Company had cash, cash equivalents, and marketable securities of $371.0 million. Based upon the Company’s current operating plans, the Company expects that its existing cash, cash equivalents, and marketable securities at June 30, 2024 to be sufficient to meet the Company’s planned operating expenses and capital expenditure requirements for at least twelve months from the issuance of these consolidated financial statements. There can be no assurance that the Company will be able to obtain additional debt or equity financing on terms acceptable to the Company or generate product revenue or revenue from collaboration partners, on a timely basis or at all. The failure of the Company to obtain sufficient funds on acceptable terms when needed could have a material adverse effect on the Company’s business, results of operations, and financial condition.

Summary of significant accounti

Summary of significant accounting policies and basis of presentation	6 Months Ended
	Jun. 30, 2024
Summary of significant accounting policies and basis of presentation
Summary of significant accounting policies and basis of presentation	2. Summary of significant accounting policies and basis of presentation Basis of Presentation The accompanying unaudited condensed consolidated financial statements of the Company have been prepared in accordance with accounting principles generally accepted in the United States (“GAAP”) for interim financial reporting. Accordingly, they do not include all of the information and footnotes required by GAAP for complete financial statements. For further information, refer to the consolidated financial statements and footnotes included in the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2023 as filed with the Securities and Exchange Commission (“SEC”) on February 28, 2024. These interim condensed consolidated financial statements, in the opinion of management, reflect all normal recurring adjustments necessary for a fair presentation of the Company’s financial position and results of operations for the periods presented. Any reference in these notes to applicable guidance is meant to refer to the authoritative United States generally accepted accounting principles as found in the Accounting Standards Codification and Accounting Standards Updates of the Financial Accounting Standards Board. Principles of Consolidation The unaudited interim consolidated financial statements include the accounts of the Company and its wholly-owned subsidiary as disclosed in Note 2, under the heading “Summary of Significant Accounting Policies and Basis of Presentation” within the “Notes to Consolidated Financial Statements” accompanying the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2023. Intercompany balances and transactions have been eliminated. Use of Estimates The preparation of consolidated financial statements in conformity 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, the Company’s management evaluates its estimates, which include, but are not limited to, estimates related to revenue recognition, incremental borrowing rate for leases, accrued expenses, stock-based compensation expense, and income taxes. The Company bases its estimates on historical experience and other market-specific or other relevant assumptions that it believes to be reasonable under the circumstances. Actual results may differ from those estimates or assumptions. Summary of Significant Accounting Policies There have been no changes in the Company's significant accounting policies as described in Note 2, “Summary of Significant Accounting Policies and Basis of Presentation” within the “Notes to Consolidated Financial Statements” accompanying the Company’s Annual Report on Form 10-K for the year ended December 31, 2023.

Fair value measurements

Fair value measurements	6 Months Ended
	Jun. 30, 2024
Fair value measurements
Fair value measurements	3. Fair value measurements Assets and liabilities measured at fair value on a recurring basis as of June 30, 2024 and December 31, 2023 are as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Quoted Prices ​ Significant ​ ​ ​ ​ ​ ​ ​ ​ in Active ​ Other ​ Significant ​ ​ ​ ​ ​ Markets for ​ Observable ​ Unobservable ​ ​ ​ ​ ​ Identical Assets ​ Inputs ​ Inputs ​ Assets Total (Level 1) (Level 2) (Level 3) June 30, 2024 ​ (in thousands) Money market funds included in cash and cash equivalents $ 63,854 $ 63,854 $ — $ — ​ Marketable securities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ U.S. Treasury notes ​ 22,714 ​ 22,714 ​ — ​ — ​ U.S. Government agency securities ​ ​ 126,706 ​ ​ 126,706 ​ ​ — ​ ​ — ​ Certificates of deposit ​ ​ 5,449 ​ ​ — ​ ​ 5,449 ​ ​ — ​ Corporate bonds ​ ​ 113,661 ​ ​ — ​ ​ 113,661 ​ ​ — ​ Commercial paper ​ ​ 26,364 ​ ​ — ​ ​ 26,364 ​ ​ — ​ Total money market funds and marketable securities ​ $ 358,748 ​ $ 213,274 ​ $ 145,474 ​ $ — ​ December 31, 2023 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Money market funds included in cash and cash equivalents $ 65,589 $ 65,589 $ — $ — ​ Marketable securities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ U.S. Treasury notes ​ ​ 103,044 ​ ​ 103,044 ​ ​ — ​ ​ — ​ U.S. Government agency securities ​ ​ 31,075 ​ ​ 31,075 ​ ​ — ​ ​ — ​ Corporate bonds ​ ​ 23,970 ​ ​ — ​ ​ 23,970 ​ ​ — ​ Commercial paper ​ ​ 3,985 ​ — ​ ​ 3,985 ​ ​ — ​ Total money market funds and marketable securities ​ $ 227,663 ​ $ 199,708 ​ $ 27,955 ​ $ — ​ ​ The Company measures the fair value of money market funds, U.S. Treasury notes and U.S. Government agency securities are based on quoted prices in active markets for identical securities. The Company measures the fair value of the Level 2 securities, certificates of deposit, corporate bonds and commercial paper, based on recent trades of securities in active markets or based on quoted market prices of similar instruments and other significant inputs derived from or corroborated by observable market data.

Cash, cash equivalents, restric

Cash, cash equivalents, restricted cash, and available-for-sale marketable securities	6 Months Ended
	Jun. 30, 2024
Cash, cash equivalents, restricted cash, and available-for-sale marketable securities
Cash, cash equivalents, restricted cash, and available-for-sale marketable securities	4. Cash, cash equivalents, restricted cash, and available-for-sale marketable securities Cash, cash equivalents, and marketable securities included the following at June 30, 2024 and December 31, 2023: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Amortized ​ Unrealized ​ Unrealized ​ Fair ​ ​ Cost Gains Losses Value ​ ​ ​ (in thousands) ​ As of June 30, 2024 ​ ​ ​ ​ ​ Money market funds included in cash and cash equivalents ​ $ 63,854 ​ $ — ​ $ — ​ $ 63,854 ​ Marketable securities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ U.S. Treasury notes ​ 22,763 ​ ​ — ​ ​ (49) ​ ​ 22,714 ​ U.S. Government agency securities ​ ​ 126,820 ​ ​ 1 ​ ​ (115) ​ ​ 126,706 ​ Certificates of deposit ​ ​ 5,447 ​ ​ 2 ​ ​ ​ ​ ​ 5,449 ​ Corporate bonds ​ ​ 113,885 ​ ​ 2 ​ ​ (226) ​ ​ 113,661 ​ Commercial paper ​ ​ 26,373 ​ ​ 1 ​ ​ (10) ​ ​ 26,364 ​ Total money market funds and marketable securities ​ $ 359,142 ​ $ 6 ​ $ (400) ​ $ 358,748 ​ As of December 31, 2023 ​ ​ ​ ​ ​ Money market funds included in cash and cash equivalents ​ $ 65,589 ​ $ — ​ $ — ​ $ 65,589 ​ Marketable securities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ U.S. Treasury notes ​ 102,966 ​ ​ 81 ​ ​ (3) ​ 103,044 ​ U.S. Government agency securities ​ ​ 31,068 ​ ​ 10 ​ ​ (3) ​ ​ 31,075 ​ Corporate bonds ​ ​ 23,975 ​ ​ 2 ​ ​ (7) ​ ​ 23,970 ​ Commercial paper ​ ​ 3,985 ​ ​ — ​ ​ — ​ ​ 3,985 ​ Total money market funds and marketable securities ​ $ 227,583 ​ $ 93 ​ $ (13) ​ $ 227,663 ​ ​ All of the Company’s marketable securities as of June 30, 2024 have a contractual maturity of one year or less. The Company reviews investments whenever the fair value of an investment is less than the amortized cost and evidence indicates that an investment’s carrying amount is not recoverable within a reasonable period of time. In connection with these investments, the Company evaluates whether the decline in fair value has resulted from credit losses or other factors, considering the extent to which fair value is less than amortized cost, any changes to the rating of the security by a rating agency, and adverse conditions specifically related to the security, among other factors. If this assessment indicates that a credit loss exists, the present value of cash flows expected to be collected from the security is compared to the amortized cost basis of the security. If the present value of cash flows expected to be collected is less than the amortized cost basis, a credit loss exists and an allowance for credit losses is recorded for the credit loss on the condensed consolidated balance sheet, limited by the amount that the fair value is less than the amortized cost basis. Any impairment that is not related to credit is recognized in other comprehensive (loss) income. Changes in the allowance for credit losses are recorded as a provision for (or reversal of) credit loss expense in general and administrative expenses within the condensed consolidated statement of operations. Losses are charged against the allowance when the Company believes the uncollectability of an available-for-sale security is confirmed or when either of the criteria regarding intent or requirement to sell is met. The Company held $268.2 million and $44.2 million in marketable securities that were in an unrealized loss position as of June 30, 2024 and December 31, 2023, respectively. The unrealized losses at June 30, 2024 and December 31, 2023 were attributable to changes in interest rates and do not represent credit losses. The Company does not intend to sell these securities and it is not more likely than not that it will be required to sell them before recovery of their amortized cost basis. The following table provides a reconciliation of cash, cash equivalents, and restricted cash within the condensed consolidated balance sheets that sum to the total of the same such amounts shown in the condensed consolidated statements of cash flows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of June 30, ​ As of December 31, ​ ​ ​ 2024 2023 ​ ​ (in thousands) ​ Cash and cash equivalents ​ $ 76,127 ​ $ 68,802 ​ Restricted cash included in deposits and other non-current assets ​ ​ 2,874 ​ ​ 1,593 ​ Total cash, cash equivalents, and restricted cash ​ $ 79,001 ​ $ 70,395 ​ ​

Accrued expenses

Accrued expenses	6 Months Ended
	Jun. 30, 2024
Accrued expenses
Accrued expenses	5. Accrued expenses Accrued expenses as of June 30, 2024 and December 31, 2023 consist of the following: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of June 30, ​ As of December 31, ​ ​ 2024 2023 ​ ​ (in thousands) ​ Employee compensation costs ​ $ 4,764 ​ $ 6,614 ​ Research and development costs ​ ​ 3,657 ​ ​ 5,225 ​ Accrued goods and services ​ ​ 912 ​ ​ 4,229 ​ Professional services ​ 940 ​ 755 ​ Total ​ $ 10,273 ​ $ 16,823 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​

Lease obligation

Lease obligation	6 Months Ended
	Jun. 30, 2024
Lease obligation
Lease obligation	6. Lease obligation Operating Leases As of June 30, 2024, the Company has a lease for laboratory and office space at 75 Hayden Avenue in Lexington, Massachusetts through January 31, 2031 and a lease for additional office and laboratory space at 64 Sidney Street in Cambridge, Massachusetts through November 30, 2026. On August 11, 2023, the Company entered into a first amendment (the “First Amendment”) to its existing lease for laboratory and office space at 75 Hayden Avenue in Lexington, Massachusetts, pursuant to which the Company agreed to lease approximately 61,307 square feet of additional office and laboratory space through January 31, 2031. The Company received $1.8 million of leasehold improvement incentives associated with the First Amendment. The Company gained control of the space on February 1, 2024 and recorded a $26.7 million right-of-use asset and a $26.7 million operating lease liability, accordingly, which reflect the leasehold improvement incentive. The Company’s lease agreements require the Company to maintain a cash deposit or irrevocable letter of credit in the aggregate amount of $2.9 million payable to its landlords as security for the performance of its obligations under the leases. These amounts are recorded as restricted cash and are included in deposits and other non-current assets in the accompanying condensed consolidated balance sheets. During the three months ended June 30, 2024, the Company vacated its leased office and laboratory space in Cambridge, Massachusetts. The Company recorded an impairment charge of $2.8 million to operating expenses during the three months ended June 30, 2024 as a result of the carrying value of the leased office and laboratory space asset group exceeding the undiscounted cash flows projected from a planned sublease of the facility which was executed in August 2024, which is disclosed in Note 13 to the unaudited condensed consolidated financial statements included elsewhere in this Quarterly Report on Form 10-Q. The impairment charge reduced the carrying value of the leased office and laboratory space asset group by $2.8 million. During the three and six months ended June 30, 2024, the Company incurred lease expenses of $4.4 million and $6.1 million, respectively. During the three and six months ended June 30, 2023, the Company incurred lease expenses of $0.9 million and $1.8 million, respectively, for operating leases. As of June 30, 2024, the weighted average remaining lease term was 5.2 years and the weighted average incremental borrowing rate used to determine the operating lease liability was 6.9%.

Commitments, contingencies and

Commitments, contingencies and other liabilities	6 Months Ended
	Jun. 30, 2024
Commitments, contingencies and other liabilities
Commitments, contingencies and other liabilities	7. Commitments, contingencies and other liabilities As of June 30, 2024 and December 31, 2023, other current and non-current liabilities consisted of the following: ​ ​ ​ ​ ​ ​ ​ ​ ​ As of June 30, ​ As of December 31, ​ ​ 2024 2023 ​ ​ (in thousands) ​ Other current liabilities ​ ​ ​ ​ ​ ​ Lease liability ​ 6,736 ​ ​ 3,200 ​ Total other current liabilities $ 6,736 ​ $ 3,200 ​ ​ ​ ​ ​ ​ ​ ​ Other non-current liabilities ​ ​ ​ ​ ​ ​ Lease liability $ 40,205 ​ $ 17,093 ​ Other ​ 1,000 ​ ​ 1,001 ​ Total other non-current liabilities $ 41,205 ​ $ 18,094 ​ ​ Other Agreements ​ ​ Litigation ​

Significant agreements

Significant agreements	6 Months Ended
	Jun. 30, 2024
Significant agreements
Significant agreements	8. Significant agreements The Company’s significant agreements are described in Note 9 of the December 31, 2023 consolidated financial statements included in its Annual Report on Form 10-K for the year ended December 31, 2023. During the three and six months ended June 30, 2024, there were no material changes to the Company’s collaboration agreements or option and license agreements and no new collaboration or license agreements. The Company recorded collaboration revenue of $29.6 million and $4.9 million during the three months ended June 30, 2024 and 2023, respectively. The Company recorded collaboration revenue of $49.1 million and $155.3 million during the six months ended June 30, 2024 and 2023, respectively. 2023 Neurocrine Collaboration Agreement In April 2024, the Company announced that the joint steering committee with Neurocrine selected a development candidate for the glucocerebrosidase 1 gene therapy program for Parkinson’s disease and other GBA1-mediated diseases (the “GBA1 program”) under the collaboration and license agreement with Neurocrine entered into in January 2023 (the “2023 Neurocrine Collaboration Agreement”). The joint steering committee selection of a development candidate for the GBA1 Program triggered a $3.0 million milestone payment to the Company. The Company recorded the $3.0 million as collaboration revenue during the three months ended June 30, 2024. 2023 Novartis Stock Purchase Agreement ​ Under the stock purchase agreement entered into in December 2023 (the “2023 Novartis Stock Purchase Agreement”), Novartis purchased 2,145,002 shares of common stock of the Company (the “Novartis Shares”) for an aggregate purchase price of approximately $20.0 million. The issuance of the Novartis Shares to Novartis pursuant to the 2023 Novartis Stock Purchase Agreement in January 2024 resulted in a premium of $0.7 million. The premium was allocated to the development and commercialization licenses granted to Novartis for two programs pursuant to the license and collaboration agreement with Novartis entered into in December 2023 and was recognized as collaboration revenue during the first quarter of 2024, upon the issuance of the Novartis Shares under the 2023 Novartis Stock Purchase Agreement. ​ 2019 Neurocrine Collaboration Agreement ​ In February 2024, the Company announced that the joint steering committee with Neurocrine selected a lead development candidate for the gene therapy program for Friedreich’s ataxia (the “FA Program”) under the collaboration and license agreement with Neurocrine entered into in January 2019 (the “2019 Neurocrine Collaboration Agreement”), which triggered a $5.0 million milestone payment to the Company that was received in the first quarter of 2024. The Company included the $5.0 million that had previously been constrained in the transaction price allocated to the FA Program performance obligation in the three months ended March 31, 2024, accordingly, which resulted in a cumulative catch-up adjustment to collaboration revenue of $4.4 million. ​ Related Party Collaboration Receivable ​ The following table presents changes in the balances of the Company’s related party collaboration receivable and contract liabilities for the 2023 Neurocrine Collaboration Agreement and the 2019 Neurocrine Collaboration Agreement during the six months ended June 30, 2024: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Balance at ​ ​ ​ ​ Balance at ​ ​ December 31, 2023 ​ Additions ​ Deductions ​ June 30, 2024 ​ ​ ​ ( in thousands) Related party collaboration receivables ​ $ 3,341 ​ $ 8,446 ​ $ (10,238) ​ $ 1,549 Contract liabilities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Deferred revenue ​ $ 75,240 ​ $ 586 ​ $ (35,837) ​ $ 39,989 ​ ​ The change in the related party collaboration receivable balance for the three months ended June 30, 2024 is primarily driven by amounts owed to the Company for research and development services provided, offset by amounts collected during the period, for the 2023 and 2019 Neurocrine Collaboration Agreements. Deferred revenue activity for the period includes the recording of $0.6 million of deferred revenue during the six months ended June 30, 2024 related to the fixed transaction price allocation increase for the FA Program, offset by $35.8 million of collaboration revenue recognized on the proportional performance model during the period for the 2023 and 2019 Neurocrine Collaboration Agreements, which is classified as either current or non-current in the accompanying consolidated balance sheet based on the period the services are expected to be delivered.

Stock-based compensation

Stock-based compensation	6 Months Ended
	Jun. 30, 2024
Stock-based compensation
Stock-based compensation	9. Stock-based compensation Stock-Based Compensation Expense Total compensation cost recognized for all stock-based compensation awards in the condensed consolidated statements of operations and comprehensive (loss) income was as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Six Months Ended ​ ​ ​ June 30, June 30, ​ 2024 2023 2024 2023 ​ ​ (in thousands) Research and development ​ $ 1,626 ​ $ 690 ​ $ 2,906 ​ $ 1,553 ​ General and administrative ​ 2,416 ​ 1,982 ​ 4,709 ​ 3,677 ​ Total stock-based compensation expense ​ $ 4,042 ​ $ 2,672 ​ $ 7,615 ​ $ 5,230 ​ ​ Stock-based compensation expense by type of award included within the condensed consolidated statements of operations and comprehensive (loss) income was as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Six Months Ended ​ ​ ​ June 30, ​ June 30, ​ ​ 2024 2023 ​ 2024 2023 ​ ​ ​ (in thousands) ​ Stock options ​ $ 2,577 ​ $ 1,903 ​ $ 4,985 ​ $ 3,566 ​ Restricted stock awards and units ​ ​ 1,382 ​ ​ 724 ​ ​ 2,471 ​ ​ 1,565 ​ Employee stock purchase plan awards ​ 83 ​ 45 ​ ​ 159 ​ ​ 99 ​ Total stock-based compensation expense ​ $ 4,042 ​ $ 2,672 ​ $ 7,615 ​ $ 5,230 ​ ​ Restricted Stock Units A summary of the status of and changes in unvested restricted stock unit activity under the Company’s equity award plans for the six months ended June 30, 2024 was as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted ​ ​ ​ ​ ​ Average ​ ​ ​ ​ ​ Grant Date ​ ​ ​ ​ ​ Fair Value ​ ​ Units Per Unit ​ Unvested restricted stock units as of December 31, 2023 1,370,897 ​ $ 6.65 ​ Granted 851,908 ​ $ 8.16 ​ Vested (381,069) ​ $ 6.06 ​ Forfeited (38,196) ​ $ 6.51 ​ Unvested restricted stock units as of June 30, 2024 1,803,540 ​ $ 7.49 ​ ​ Stock-based compensation of restricted stock units is based on the fair value of the Company’s common stock on the date of grant and is recognized over the vesting period. All of the restricted stock units granted in the six months ended June 30, 2024 vest in equal amounts, annually over three years. The stock-based compensation expense related to restricted stock units was $1.4 million and $2.5 million for the three and six months ended June 30, 2024, respectively. The stock-based compensation expense related to restricted stock units was $0.7 million and $1.6 million for the three and six months ended June 30, 2023, respectively. As of June 30, 2024, the Company had unrecognized stock-based compensation expense related to its unvested restricted stock units of $11.1 million, which is expected to be recognized over the remaining average vesting period of 2.3 years. Stock Options The following is a summary of stock option activity for the six months ended June 30, 2024: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted Remaining Aggregate ​ ​ ​ ​ ​ Average ​ Contractual ​ Intrinsic ​ ​ ​ ​ ​ Exercise ​ Life ​ Value ​ ​ Shares Price (in years) (in thousands) ​ Outstanding at December 31, 2023 7,425,444 ​ $ 8.52 ​ ​ ​ ​ ​ ​ Granted 1,999,926 ​ $ 7.81 ​ ​ ​ ​ ​ ​ Exercised (58,458) ​ $ 4.47 ​ ​ ​ ​ ​ ​ Cancelled or forfeited (500,794) ​ $ 14.40 ​ ​ ​ ​ ​ ​ Outstanding at June 30, 2024 8,866,118 ​ $ 8.05 7.4 ​ ​ 9,481 ​ Exercisable at June 30, 2024 4,212,635 ​ $ 8.57 6.4 ​ $ 5,862 ​ ​ As of June 30, 2024, the Company had unrecognized stock-based compensation expense related to its unvested stock options of $22.0 million which is expected to be recognized over the remaining weighted-average vesting period of 2.8 years.

Net (loss) income per share

Net (loss) income per share	6 Months Ended
	Jun. 30, 2024
Net (loss) income per share
Net (loss) income per share	10. Net (loss) income per share The following table sets forth the outstanding potentially dilutive securities that have been excluded in the calculation of diluted net (loss) income per share because to include them would be anti-dilutive: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended June 30, ​ ​ Six Months Ended June 30, ​ ​ ​ 2024 ​ 2023 ​ 2024 ​ 2023 ​ Unvested restricted common stock awards ​ 22,500 ​ ​ 45,000 ​ 22,500 ​ ​ 45,000 ​ Unvested restricted common stock units ​ ​ 1,803,540 ​ ​ 1,313,500 ​ ​ 1,803,540 ​ ​ 725,876 ​ Outstanding stock options ​ 8,866,118 ​ ​ 7,334,771 ​ 8,866,118 ​ ​ 6,253,497 ​ Total ​ 10,692,158 ​ ​ 8,693,271 ​ 10,692,158 ​ ​ 7,024,373 ​ ​ Basic and diluted weighted-average shares outstanding are as follows for the three and six months ended June 30, 2024 and 2023: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended June 30, ​ ​ Six Months Ended June 30, ​ ​ ​ 2024 ​ ​ 2023 ​ ​ 2024 ​ ​ 2023 ​ ​ ​ ​ ​ ​ ​ Numerator: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net (loss) income (in thousands) ​ $ (10,141) ​ $ (22,208) ​ $ (21,471) ​ $ 101,836 Denominator for basic net (loss) income per share: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted average shares outstanding-basic ​ ​ 57,721,934 ​ ​ 43,520,137 ​ ​ 57,419,490 ​ ​ 42,102,101 Denominator for diluted net (loss) income per share: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted average shares outstanding-basic ​ ​ 57,721,934 ​ ​ 43,520,137 ​ ​ 57,419,490 ​ ​ 42,102,101 Common stock options and restricted stock units ​ ​ — ​ ​ — ​ ​ — ​ ​ 1,668,898 Weighted average shares outstanding-diluted ​ ​ 57,721,934 ​ ​ 43,520,137 ​ ​ 57,419,490 ​ ​ 43,770,999 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net (loss) income per share, basic: ​ $ (0.18) ​ $ (0.51) ​ $ (0.37) ​ $ 2.42 Net (loss) income per share, diluted: ​ $ (0.18) ​ $ (0.51) ​ $ (0.37) ​ $ 2.33 ​ ​ ​ The pre ghted average shares outstanding for the three and six months ended June 30, 2024.

Underwritten public offering

Underwritten public offering	6 Months Ended
	Jun. 30, 2024
Underwritten public offering
Underwritten public offering	11. Underwritten public offering ​ On January 4, 2024, the Company entered into an underwriting agreement (the “Underwriting Agreement”) with Citigroup Global Markets Inc. and Guggenheim Securities, LLC, as representatives of the several underwriters named therein (the “Underwriters”), relating to an underwritten public offering of 7,777,778 shares of the Company’s common stock, par value $0.001 per share, and, in lieu of common stock to certain investors, pre-funded warrants (the “Pre-Funded Warrants”) to purchase up to 3,333,333 shares of common stock. The Underwriters agreed to purchase the Company’s stock from the Company pursuant to the Underwriting Agreement at a price of $8.46 and the Pre-Funded Warrants from the Company pursuant to the Underwriting Agreement at a price of $8.459 per share underlying each Pre-Funded Warrant. ​ ​

Related party transactions

Related party transactions	6 Months Ended
	Jun. 30, 2024
Related party transactions
Related party transactions	12. Related-party transactions During the three and six months ended June 30, 2024, the Company received scientific advisory board and other scientific advisory services from Dinah Sah, Ph.D., the Company’s former Chief Scientific Officer. The total amount of fees paid to Dr. Sah for services provided during the three and six months ended June 30, 2024, was $150,000 and $300,000, respectively. The total amount of fees paid to Dr. Sah for services provided during the three and six months ended June 30, 2023 was $184,000 and $383,800, respectively. During the second quarter of 2023, the Company and Dr. Sah agreed to a fee of $50,000 per month for advisory services from Dr. Sah pursuant to an amendment to the Company’s consulting agreement with Dr. Sah that became effective in June 2023. Under each of the Company’s collaboration agreements with Neurocrine, the Company and Neurocrine have agreed to conduct research, development, and commercialization activities for certain of the Company’s AAV gene therapy product candidates. Amounts due from Neurocrine are reflected as related party collaboration receivables. As of June 30, 2024, the Company had approximately $0.9 million in related party collaboration receivables associated with the 2023 Neurocrine Collaboration Agreement and approximately $0.7 million in related party collaboration receivables associated with the 2019 Neurocrine Collaboration Agreement.

Subsequent Events

Subsequent Events	6 Months Ended
	Jun. 30, 2024
Subsequent Events
Subsequent Events	13. Subsequent Events ​ In August 2024, the Company entered into an agreement (the “Sublease”) to sublease the office and laboratory space leased by the Company at 64 Sidney Street in Cambridge, Massachusetts to a third party (the “Subtenant”). The term of the Sublease is approximately two years and the Company expects to receive approximately $2.6 million from the Subtenant over the term. Prior to entering the Sublease, the Company had fully vacated the space at 64 Sidney Street in Cambridge, Massachusetts. ​

Pay vs Performance Disclosure

Pay vs Performance Disclosure - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2024	Mar. 31, 2024	Jun. 30, 2023	Mar. 31, 2023	Jun. 30, 2024	Jun. 30, 2023
Pay vs Performance Disclosure
Net Income (Loss)	$ (10,141)	$ (11,330)	$ (22,208)	$ 124,044	$ (21,471)	$ 101,836

Insider Trading Arrangements

Insider Trading Arrangements	3 Months Ended
	Jun. 30, 2024
Trading Arrangements, by Individual
Rule 10b5-1 Arrangement Adopted	false
Non-Rule 10b5-1 Arrangement Adopted	false
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false

Summary of significant accoun_2

Summary of significant accounting policies and basis of presentation (Policies)	6 Months Ended
	Jun. 30, 2024
Summary of significant accounting policies and basis of presentation
Basis of Presentation	Basis of Presentation The accompanying unaudited condensed consolidated financial statements of the Company have been prepared in accordance with accounting principles generally accepted in the United States (“GAAP”) for interim financial reporting. Accordingly, they do not include all of the information and footnotes required by GAAP for complete financial statements. For further information, refer to the consolidated financial statements and footnotes included in the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2023 as filed with the Securities and Exchange Commission (“SEC”) on February 28, 2024. These interim condensed consolidated financial statements, in the opinion of management, reflect all normal recurring adjustments necessary for a fair presentation of the Company’s financial position and results of operations for the periods presented. Any reference in these notes to applicable guidance is meant to refer to the authoritative United States generally accepted accounting principles as found in the Accounting Standards Codification and Accounting Standards Updates of the Financial Accounting Standards Board.
Principles of Consolidation	Principles of Consolidation The unaudited interim consolidated financial statements include the accounts of the Company and its wholly-owned subsidiary as disclosed in Note 2, under the heading “Summary of Significant Accounting Policies and Basis of Presentation” within the “Notes to Consolidated Financial Statements” accompanying the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2023. Intercompany balances and transactions have been eliminated.
Use of Estimates	Use of Estimates The preparation of consolidated financial statements in conformity 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, the Company’s management evaluates its estimates, which include, but are not limited to, estimates related to revenue recognition, incremental borrowing rate for leases, accrued expenses, stock-based compensation expense, and income taxes. The Company bases its estimates on historical experience and other market-specific or other relevant assumptions that it believes to be reasonable under the circumstances. Actual results may differ from those estimates or assumptions.
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies There have been no changes in the Company's significant accounting policies as described in Note 2, “Summary of Significant Accounting Policies and Basis of Presentation” within the “Notes to Consolidated Financial Statements” accompanying the Company’s Annual Report on Form 10-K for the year ended December 31, 2023.

Fair value measurements (Tables

Fair value measurements (Tables)	6 Months Ended
	Jun. 30, 2024
Fair value measurements
Schedule of assets and liabilities measured at fair value on a recurring basis	Assets and liabilities measured at fair value on a recurring basis as of June 30, 2024 and December 31, 2023 are as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Quoted Prices ​ Significant ​ ​ ​ ​ ​ ​ ​ ​ in Active ​ Other ​ Significant ​ ​ ​ ​ ​ Markets for ​ Observable ​ Unobservable ​ ​ ​ ​ ​ Identical Assets ​ Inputs ​ Inputs ​ Assets Total (Level 1) (Level 2) (Level 3) June 30, 2024 ​ (in thousands) Money market funds included in cash and cash equivalents $ 63,854 $ 63,854 $ — $ — ​ Marketable securities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ U.S. Treasury notes ​ 22,714 ​ 22,714 ​ — ​ — ​ U.S. Government agency securities ​ ​ 126,706 ​ ​ 126,706 ​ ​ — ​ ​ — ​ Certificates of deposit ​ ​ 5,449 ​ ​ — ​ ​ 5,449 ​ ​ — ​ Corporate bonds ​ ​ 113,661 ​ ​ — ​ ​ 113,661 ​ ​ — ​ Commercial paper ​ ​ 26,364 ​ ​ — ​ ​ 26,364 ​ ​ — ​ Total money market funds and marketable securities ​ $ 358,748 ​ $ 213,274 ​ $ 145,474 ​ $ — ​ December 31, 2023 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Money market funds included in cash and cash equivalents $ 65,589 $ 65,589 $ — $ — ​ Marketable securities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ U.S. Treasury notes ​ ​ 103,044 ​ ​ 103,044 ​ ​ — ​ ​ — ​ U.S. Government agency securities ​ ​ 31,075 ​ ​ 31,075 ​ ​ — ​ ​ — ​ Corporate bonds ​ ​ 23,970 ​ ​ — ​ ​ 23,970 ​ ​ — ​ Commercial paper ​ ​ 3,985 ​ — ​ ​ 3,985 ​ ​ — ​ Total money market funds and marketable securities ​ $ 227,663 ​ $ 199,708 ​ $ 27,955 ​ $ — ​

Cash, cash equivalents, restr_2

Cash, cash equivalents, restricted cash, and available-for-sale marketable securities (Tables)	6 Months Ended
	Jun. 30, 2024
Cash, cash equivalents, restricted cash, and available-for-sale marketable securities
Schedule of money market funds and marketable securities	Cash, cash equivalents, and marketable securities included the following at June 30, 2024 and December 31, 2023: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Amortized ​ Unrealized ​ Unrealized ​ Fair ​ ​ Cost Gains Losses Value ​ ​ ​ (in thousands) ​ As of June 30, 2024 ​ ​ ​ ​ ​ Money market funds included in cash and cash equivalents ​ $ 63,854 ​ $ — ​ $ — ​ $ 63,854 ​ Marketable securities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ U.S. Treasury notes ​ 22,763 ​ ​ — ​ ​ (49) ​ ​ 22,714 ​ U.S. Government agency securities ​ ​ 126,820 ​ ​ 1 ​ ​ (115) ​ ​ 126,706 ​ Certificates of deposit ​ ​ 5,447 ​ ​ 2 ​ ​ ​ ​ ​ 5,449 ​ Corporate bonds ​ ​ 113,885 ​ ​ 2 ​ ​ (226) ​ ​ 113,661 ​ Commercial paper ​ ​ 26,373 ​ ​ 1 ​ ​ (10) ​ ​ 26,364 ​ Total money market funds and marketable securities ​ $ 359,142 ​ $ 6 ​ $ (400) ​ $ 358,748 ​ As of December 31, 2023 ​ ​ ​ ​ ​ Money market funds included in cash and cash equivalents ​ $ 65,589 ​ $ — ​ $ — ​ $ 65,589 ​ Marketable securities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ U.S. Treasury notes ​ 102,966 ​ ​ 81 ​ ​ (3) ​ 103,044 ​ U.S. Government agency securities ​ ​ 31,068 ​ ​ 10 ​ ​ (3) ​ ​ 31,075 ​ Corporate bonds ​ ​ 23,975 ​ ​ 2 ​ ​ (7) ​ ​ 23,970 ​ Commercial paper ​ ​ 3,985 ​ ​ — ​ ​ — ​ ​ 3,985 ​ Total money market funds and marketable securities ​ $ 227,583 ​ $ 93 ​ $ (13) ​ $ 227,663 ​
Reconciliation of cash, cash equivalents, and restricted cash	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of June 30, ​ As of December 31, ​ ​ ​ 2024 2023 ​ ​ (in thousands) ​ Cash and cash equivalents ​ $ 76,127 ​ $ 68,802 ​ Restricted cash included in deposits and other non-current assets ​ ​ 2,874 ​ ​ 1,593 ​ Total cash, cash equivalents, and restricted cash ​ $ 79,001 ​ $ 70,395 ​ ​

Accrued expenses (Tables)

Accrued expenses (Tables)	6 Months Ended
	Jun. 30, 2024
Accrued expenses
Schedule of accrued expenses	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of June 30, ​ As of December 31, ​ ​ 2024 2023 ​ ​ (in thousands) ​ Employee compensation costs ​ $ 4,764 ​ $ 6,614 ​ Research and development costs ​ ​ 3,657 ​ ​ 5,225 ​ Accrued goods and services ​ ​ 912 ​ ​ 4,229 ​ Professional services ​ 940 ​ 755 ​ Total ​ $ 10,273 ​ $ 16,823 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​

Commitments, contingencies an_2

Commitments, contingencies and other liabilities (Tables)	6 Months Ended
	Jun. 30, 2024
Commitments, contingencies and other liabilities
Summary of other current and non-current liabilities	​ ​ ​ ​ ​ ​ ​ ​ ​ As of June 30, ​ As of December 31, ​ ​ 2024 2023 ​ ​ (in thousands) ​ Other current liabilities ​ ​ ​ ​ ​ ​ Lease liability ​ 6,736 ​ ​ 3,200 ​ Total other current liabilities $ 6,736 ​ $ 3,200 ​ ​ ​ ​ ​ ​ ​ ​ Other non-current liabilities ​ ​ ​ ​ ​ ​ Lease liability $ 40,205 ​ $ 17,093 ​ Other ​ 1,000 ​ ​ 1,001 ​ Total other non-current liabilities $ 41,205 ​ $ 18,094 ​

Significant agreements (Tables)

Significant agreements (Tables)	6 Months Ended
	Jun. 30, 2024
2023 Neurocrine Collaborative Agreement and 2019 Neurocrine Collaborative Agreement
Schedule of collaboration receivables and contract liabilities	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Balance at ​ ​ ​ ​ Balance at ​ ​ December 31, 2023 ​ Additions ​ Deductions ​ June 30, 2024 ​ ​ ​ ( in thousands) Related party collaboration receivables ​ $ 3,341 ​ $ 8,446 ​ $ (10,238) ​ $ 1,549 Contract liabilities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Deferred revenue ​ $ 75,240 ​ $ 586 ​ $ (35,837) ​ $ 39,989

Stock-based compensation (Table

Stock-based compensation (Tables)	6 Months Ended
	Jun. 30, 2024
Stock-based compensation
Compensation cost recognized for all stock-based compensation awards	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Six Months Ended ​ ​ ​ June 30, June 30, ​ 2024 2023 2024 2023 ​ ​ (in thousands) Research and development ​ $ 1,626 ​ $ 690 ​ $ 2,906 ​ $ 1,553 ​ General and administrative ​ 2,416 ​ 1,982 ​ 4,709 ​ 3,677 ​ Total stock-based compensation expense ​ $ 4,042 ​ $ 2,672 ​ $ 7,615 ​ $ 5,230 ​
Summary of stock-based compensation expense by type of award	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Six Months Ended ​ ​ ​ June 30, ​ June 30, ​ ​ 2024 2023 ​ 2024 2023 ​ ​ ​ (in thousands) ​ Stock options ​ $ 2,577 ​ $ 1,903 ​ $ 4,985 ​ $ 3,566 ​ Restricted stock awards and units ​ ​ 1,382 ​ ​ 724 ​ ​ 2,471 ​ ​ 1,565 ​ Employee stock purchase plan awards ​ 83 ​ 45 ​ ​ 159 ​ ​ 99 ​ Total stock-based compensation expense ​ $ 4,042 ​ $ 2,672 ​ $ 7,615 ​ $ 5,230 ​
Summary of status and changes in unvested restricted stock	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted ​ ​ ​ ​ ​ Average ​ ​ ​ ​ ​ Grant Date ​ ​ ​ ​ ​ Fair Value ​ ​ Units Per Unit ​ Unvested restricted stock units as of December 31, 2023 1,370,897 ​ $ 6.65 ​ Granted 851,908 ​ $ 8.16 ​ Vested (381,069) ​ $ 6.06 ​ Forfeited (38,196) ​ $ 6.51 ​ Unvested restricted stock units as of June 30, 2024 1,803,540 ​ $ 7.49 ​
Summary of stock option activity	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted Remaining Aggregate ​ ​ ​ ​ ​ Average ​ Contractual ​ Intrinsic ​ ​ ​ ​ ​ Exercise ​ Life ​ Value ​ ​ Shares Price (in years) (in thousands) ​ Outstanding at December 31, 2023 7,425,444 ​ $ 8.52 ​ ​ ​ ​ ​ ​ Granted 1,999,926 ​ $ 7.81 ​ ​ ​ ​ ​ ​ Exercised (58,458) ​ $ 4.47 ​ ​ ​ ​ ​ ​ Cancelled or forfeited (500,794) ​ $ 14.40 ​ ​ ​ ​ ​ ​ Outstanding at June 30, 2024 8,866,118 ​ $ 8.05 7.4 ​ ​ 9,481 ​ Exercisable at June 30, 2024 4,212,635 ​ $ 8.57 6.4 ​ $ 5,862 ​

Net (loss) income per share (Ta

Net (loss) income per share (Tables)	6 Months Ended
	Jun. 30, 2024
Net (loss) income per share
Outstanding potentially dilutive securities excluded in the calculation of diluted net (loss) income per share	The following table sets forth the outstanding potentially dilutive securities that have been excluded in the calculation of diluted net (loss) income per share because to include them would be anti-dilutive: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended June 30, ​ ​ Six Months Ended June 30, ​ ​ ​ 2024 ​ 2023 ​ 2024 ​ 2023 ​ Unvested restricted common stock awards ​ 22,500 ​ ​ 45,000 ​ 22,500 ​ ​ 45,000 ​ Unvested restricted common stock units ​ ​ 1,803,540 ​ ​ 1,313,500 ​ ​ 1,803,540 ​ ​ 725,876 ​ Outstanding stock options ​ 8,866,118 ​ ​ 7,334,771 ​ 8,866,118 ​ ​ 6,253,497 ​ Total ​ 10,692,158 ​ ​ 8,693,271 ​ 10,692,158 ​ ​ 7,024,373 ​
Schedule of weighted average number of shares, basic and diluted	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended June 30, ​ ​ Six Months Ended June 30, ​ ​ ​ 2024 ​ ​ 2023 ​ ​ 2024 ​ ​ 2023 ​ ​ ​ ​ ​ ​ ​ Numerator: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net (loss) income (in thousands) ​ $ (10,141) ​ $ (22,208) ​ $ (21,471) ​ $ 101,836 Denominator for basic net (loss) income per share: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted average shares outstanding-basic ​ ​ 57,721,934 ​ ​ 43,520,137 ​ ​ 57,419,490 ​ ​ 42,102,101 Denominator for diluted net (loss) income per share: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted average shares outstanding-basic ​ ​ 57,721,934 ​ ​ 43,520,137 ​ ​ 57,419,490 ​ ​ 42,102,101 Common stock options and restricted stock units ​ ​ — ​ ​ — ​ ​ — ​ ​ 1,668,898 Weighted average shares outstanding-diluted ​ ​ 57,721,934 ​ ​ 43,520,137 ​ ​ 57,419,490 ​ ​ 43,770,999 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net (loss) income per share, basic: ​ $ (0.18) ​ $ (0.51) ​ $ (0.37) ​ $ 2.42 Net (loss) income per share, diluted: ​ $ (0.18) ​ $ (0.51) ​ $ (0.37) ​ $ 2.33

Nature of business (Details)

Nature of business (Details) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Nature of business
Accumulated deficit	$ (282,653)	$ (261,182)
Cash, cash equivalents, and marketable securities	$ 371,000

Fair value measurements - Asset

Fair value measurements - Assets and liabilities measured on a recurring basis - (Details) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Assets, Fair Value Disclosure [Abstract]
Cash and cash equivalents	$ 76,127	$ 68,802
Fair value, measurements, recurring
Assets, Fair Value Disclosure [Abstract]
Total money market funds and marketable securities	358,748	227,663
Level 1 | Fair value, measurements, recurring
Assets, Fair Value Disclosure [Abstract]
Total money market funds and marketable securities	213,274	199,708
Level 2 | Fair value, measurements, recurring
Assets, Fair Value Disclosure [Abstract]
Total money market funds and marketable securities	145,474	27,955
U.S. Treasury notes | Fair value, measurements, recurring
Assets, Fair Value Disclosure [Abstract]
Marketable securities	22,714	103,044
U.S. Treasury notes | Level 1 | Fair value, measurements, recurring
Assets, Fair Value Disclosure [Abstract]
Marketable securities	22,714	103,044
U. S. Government agency securities | Fair value, measurements, recurring
Assets, Fair Value Disclosure [Abstract]
Marketable securities	126,706	31,075
U. S. Government agency securities | Level 1 | Fair value, measurements, recurring
Assets, Fair Value Disclosure [Abstract]
Marketable securities	126,706	31,075
Corporate bonds | Fair value, measurements, recurring
Assets, Fair Value Disclosure [Abstract]
Marketable securities	113,661	23,970
Corporate bonds | Level 2 | Fair value, measurements, recurring
Assets, Fair Value Disclosure [Abstract]
Marketable securities	113,661	23,970
Commercial paper | Fair value, measurements, recurring
Assets, Fair Value Disclosure [Abstract]
Marketable securities	26,364	3,985
Commercial paper | Level 2 | Fair value, measurements, recurring
Assets, Fair Value Disclosure [Abstract]
Marketable securities	26,364	3,985
Money market funds
Assets, Fair Value Disclosure [Abstract]
Cash and cash equivalents	63,854	65,589
Money market funds | Fair value, measurements, recurring
Assets, Fair Value Disclosure [Abstract]
Cash and cash equivalents	63,854	65,589
Money market funds | Level 1 | Fair value, measurements, recurring
Assets, Fair Value Disclosure [Abstract]
Cash and cash equivalents	63,854	$ 65,589
Certificates of deposits | Fair value, measurements, recurring
Assets, Fair Value Disclosure [Abstract]
Marketable securities	5,449
Certificates of deposits | Level 2 | Fair value, measurements, recurring
Assets, Fair Value Disclosure [Abstract]
Marketable securities	$ 5,449

Cash, cash equivalents, restr_3

Cash, cash equivalents, restricted cash and available-for-sale marketable securities - Cash, cash equivalents, and marketable securities (Details) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Amortized Cost
Cash and cash equivalents	$ 76,127	$ 68,802
Total money market funds and marketable securities	359,142	227,583
Debt securities, unrealized loss position	268,200	44,200
Fair Value
Total money market funds and marketable securities	358,748	227,663
Unrealized Gains and Losses
Marketable securities, unrealized gains	6	93
Marketable securities, unrealized losses	(400)	(13)
Money market funds
Amortized Cost
Cash and cash equivalents	63,854	65,589
Fair Value
Cash and cash equivalents, fair value	63,854	65,589
Certificates of deposits
Amortized Cost
Marketable securities, Amortized cost	5,447
Fair Value
Marketable securities, fair value	5,449
Unrealized Gains and Losses
Marketable securities, unrealized gains	2
U.S. Treasury notes
Amortized Cost
Marketable securities, Amortized cost	22,763	102,966
Fair Value
Marketable securities, fair value	22,714	103,044
Unrealized Gains and Losses
Marketable securities, unrealized gains		81
Marketable securities, unrealized losses	(49)	(3)
U. S. Government agency securities
Amortized Cost
Marketable securities, Amortized cost	126,820	31,068
Fair Value
Marketable securities, fair value	126,706	31,075
Unrealized Gains and Losses
Marketable securities, unrealized gains	1	10
Marketable securities, unrealized losses	(115)	(3)
Corporate bonds
Amortized Cost
Marketable securities, Amortized cost	113,885	23,975
Fair Value
Marketable securities, fair value	113,661	23,970
Unrealized Gains and Losses
Marketable securities, unrealized gains	2	2
Marketable securities, unrealized losses	(226)	(7)
Commercial paper
Amortized Cost
Marketable securities, Amortized cost	26,373	3,985
Fair Value
Marketable securities, fair value	26,364	$ 3,985
Unrealized Gains and Losses
Marketable securities, unrealized gains	1
Marketable securities, unrealized losses	$ (10)

Cash, cash equivalents, restr_4

Cash, cash equivalents, restricted cash and available-for-sale marketable securities - Reconciliation of cash, cash equivalents, and restricted cash (Details) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023	Jun. 30, 2023	Dec. 31, 2022
Cash, cash equivalents, restricted cash, and available-for-sale marketable securities
Cash and cash equivalents	$ 76,127	$ 68,802
Restricted cash included in deposits and other noncurrent assets	2,874	1,593
Total cash, cash equivalents, and restricted cash	$ 79,001	$ 70,395	$ 245,886	$ 100,474

Accrued expenses (Details)

Accrued expenses (Details) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Accrued expenses
Employee compensation costs	$ 4,764	$ 6,614
Research and development costs	3,657	5,225
Accrued goods and services	912	4,229
Professional services	940	755
Total	$ 10,273	$ 16,823

Lease obligation (Details)

Lease obligation (Details) $ in Thousands		3 Months Ended		6 Months Ended
	Aug. 11, 2023 USD ($) ft²	Jun. 30, 2024 USD ($)	Jun. 30, 2023 USD ($)	Jun. 30, 2024 USD ($)	Jun. 30, 2023 USD ($)	Feb. 01, 2024 USD ($)	Dec. 31, 2023 USD ($)
Operating lease, right-of-use assets		$ 35,514		$ 35,514			$ 13,510
Lease liability		40,205		40,205			17,093
Restricted cash included in deposits and other noncurrent assets		2,874		2,874			$ 1,593
Impairment charge				2,776
Lease expense		$ 4,400	$ 900	$ 6,100	$ 1,800
Weighted average remaining lease term		5 years 2 months 12 days		5 years 2 months 12 days
Weighted average incremental borrowing rate		6.90%		6.90%
75 and 64 Sidney Street
Restricted cash included in deposits and other noncurrent assets		$ 2,900		$ 2,900
64 Sidney Street
Impairment charge		$ 2,800
75 Hayden avenue
Area of additional facility leased | ft²	61,307
Leasehold improvements amount	$ 1,800
Operating lease, right-of-use assets						$ 26,700
Lease liability						$ 26,700

Commitments, contingencies, and

Commitments, contingencies, and other liabilities (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2016 USD ($) multiple	Jun. 30, 2024 USD ($)	Dec. 31, 2023 USD ($)	Dec. 31, 2017 USD ($)
Other current liabilities
Lease liability		$ 6,736	$ 3,200
Total other current liabilities		6,736	3,200
Other non-current liabilities
Lease liability		40,205	17,093
Other		1,000	1,001
Total other non-current liabilities		$ 41,205	$ 18,094
Non-profit organization agreement
Other non-current liabilities
Maximum funding	$ 4,000
Funding multiple | multiple	2.6
Milestone payment liability				$ 1,000

Significant Agreements - Neuroc

Significant Agreements - Neurocrine Collaboration Agreements (Details) $ in Thousands	1 Months Ended	3 Months Ended			6 Months Ended
	Apr. 30, 2024 USD ($)	Jun. 30, 2024 USD ($)	Mar. 31, 2024 USD ($)	Jun. 30, 2023 USD ($)	Jun. 30, 2024 USD ($) agreement	Jun. 30, 2023 USD ($)
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Number of new agreements | agreement					0
Collaboration revenue		$ 29,578		$ 4,853	$ 49,094	$ 155,333
2019 Neurocrine Collaborative Agreement | Neurocrine
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Milestone payments received			$ 5,000
Allocation of transaction price			5,000
Cumulative catch up of revenue recognized			$ 4,400
2023 Neurocrine Collaborative Agreement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Milestone payments	$ 3,000
Revenue from contract with customer		$ 3,000

Significant Agreements - Novart

Significant Agreements - Novartis Agreements (Details) - Novartis Pharma, AG - 2023 Novartis Collaboration Agreement $ in Millions	Dec. 28, 2023 USD ($) shares
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Shares of common stock | shares	2,145,002
Aggregate purchase price	$ 20
Amount of premium	$ 0.7

Significant Agreements - Neur_2

Significant Agreements - Neurocrine Collaboration receivables and contract liabilities (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2024 USD ($)
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Related party collaboration receivables, beginning balance	$ 3,341
Related party collaboration receivables, ending balance	1,549
2023 Neurocrine Collaborative Agreement and 2019 Neurocrine Collaborative Agreement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Related party collaboration receivables, beginning balance	3,341
Additions	8,446
Deductions	(10,238)
Related party collaboration receivables, ending balance	1,549
Deferred revenue, beginning balance	75,240
Additions	586
Deductions	(35,837)
Deferred revenue, ending balance	39,989
Discovery program 3 | Neurocrine | 2023 Neurocrine Collaborative Agreement and 2019 Neurocrine Collaborative Agreement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Additions	600
Deductions	$ (35,800)

Stock-based compensation - Comp

Stock-based compensation - Compensation expense (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation	$ 4,042	$ 2,672	$ 7,615	$ 5,230
Employee Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation	2,577	1,903	4,985	3,566
Restricted stock awards and units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation	1,382	724	2,471	1,565
Employee stock purchase plan awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation	83	45	159	99
Research and development
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation	1,626	690	2,906	1,553
General and administrative
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation	$ 2,416	$ 1,982	$ 4,709	$ 3,677

Stock-based compensation - Rest

Stock-based compensation - Restricted Stock - (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Restricted stock disclosures
Stock-based compensation.	$ 4,042	$ 2,672	$ 7,615	$ 5,230
Unvested restricted common stock units
Shares
Balance, beginning (in shares)			1,370,897
Granted (in shares)			851,908
Vested (in shares)			(381,069)
Forfeited (in shares)			(38,196)
Balance, ending (in shares)	1,803,540		1,803,540
Weighted Average Grant Date Fair Value Per Share
Balance, beginning (in dollars per share)			$ 6.65
Granted (in dollars per share)			8.16
Vested (in dollars per share)			6.06
Forfeited (in dollars per share)			6.51
Balance, ending (in dollars per share)	$ 7.49		$ 7.49
Restricted stock disclosures
Vesting period			3 years
Stock-based compensation.	$ 1,382	$ 724	$ 2,471	$ 1,565
Unrecognized stock-based compensation expense	$ 11,100		$ 11,100
Remaining weighted-average remaining vesting period			2 years 3 months 18 days

Stock-based compensation - Stoc

Stock-based compensation - Stock Options - (Details) - USD ($) $ / shares in Units, $ in Thousands	6 Months Ended
	Jun. 30, 2024
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Outstanding, beginning balance (in shares)	7,425,444
Granted (in shares)	1,999,926
Exercised (in shares)	(58,458)
Cancelled or forfeited (in shares)	(500,794)
Outstanding, ending balance (in shares)	8,866,118
Exercisable (in shares)	4,212,635
Weighted Average Exercise Price
Outstanding (in dollars per share)	$ 8.52
Granted (in dollars per share)	7.81
Exercised (in dollars per share)	4.47
Cancelled or forfeited (in dollars per share)	14.40
Outstanding (in dollars per share)	8.05
Exercisable (in dollars per share)	$ 8.57
Remaining Contractual Life
Outstanding	7 years 4 months 24 days
Exercisable	6 years 4 months 24 days
Aggregate Intrinsic Value
Outstanding	$ 9,481
Exercisable	5,862
Employee Stock Option [Member]
Options disclosures
Unrecognized stock-based compensation expense	$ 22,000
Remaining weighted-average remaining vesting period	2 years 9 months 18 days

Net (loss) income per share (De

Net (loss) income per share (Details) - shares	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Antidilutive Securities Excluded from Computation of Earnings Per Share
Antidilutive securities	10,692,158	8,693,271	10,692,158	7,024,373
Unvested restricted common stock awards
Antidilutive Securities Excluded from Computation of Earnings Per Share
Antidilutive securities	22,500	45,000	22,500	45,000
Unvested restricted common stock units
Antidilutive Securities Excluded from Computation of Earnings Per Share
Antidilutive securities	1,803,540	1,313,500	1,803,540	725,876
Employee Stock Option [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share
Antidilutive securities	8,866,118	7,334,771	8,866,118	6,253,497

Net (loss) income per share - B

Net (loss) income per share - Basic and diluted weighted average shares outstanding (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Numerator:
Net (loss) income	$ (10,141)	$ (22,208)	$ (21,471)	$ 101,836
Denominator for basic net income (loss) per share:
Weighted average shares outstanding-basic	57,721,934	43,520,137	57,419,490	42,102,101
Denominator for diluted net income (loss) per share:
Weighted average shares outstanding-basic	57,721,934	43,520,137	57,419,490	42,102,101
Common stock options and restricted stock units				1,668,898
Weighted average shares outstanding-diluted	57,721,934	43,520,137	57,419,490	43,770,999
Net (loss) income per share, basic	$ (0.18)	$ (0.51)	$ (0.37)	$ 2.42
Net (loss) income per share, diluted	$ (0.18)	$ (0.51)	$ (0.37)	$ 2.33

Underwritten public offering (D

Underwritten public offering (Details) - USD ($) $ / shares in Units, $ in Millions	Jan. 09, 2024	Jun. 30, 2024	Jan. 04, 2024	Dec. 31, 2023
Underwritten public offering
Par value of common stock (in dollars per share)		$ 0.001		$ 0.001
Underwriting Agreement
Underwritten public offering
Issuance of common stock, shares	7,777,778
Par value of common stock (in dollars per share)			$ 0.001
Offering price for common stock			8.46
Net proceeds received	$ 93.5
Underwriting Agreement | Pre-Funded Warrants
Underwritten public offering
Number of warrants issued to purchase common stock	3,333,333
Price per warrant			$ 8.459
Issuance of Pre-Funded Warrants	3,333,333

Related party transactions (Det

Related party transactions (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023	Dec. 31, 2023
Related party transactions
Related party collaboration receivable	$ 1,549,000		$ 1,549,000		$ 3,341,000
Dr. Sah | Related Party
Related party transactions
Total amount of services received	150,000	$ 184,000	300,000	$ 383,800
Advisory fee amount per month		$ 50,000		$ 50,000
Neurocrine Collaborative Agreement 2019
Related party transactions
Related party collaboration receivable	700,000		700,000
Neurocrine Collaborative Agreement 2023
Related party transactions
Related party collaboration receivable	$ 900,000		$ 900,000

Subsequent Events - (Details)

Subsequent Events - (Details) - Subsequent Event. $ in Millions	1 Months Ended
	Aug. 31, 2024 USD ($)
Subsequent Events
Term of sublease	2 years
Expected proceeds over term of sublease agreement	$ 2.6