Rocket Pharmaceuticals (RCKT) 10-Q 7 Nov 24 2024 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2024	Nov. 05, 2024
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2024
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	Q3
Document Transition Report	false
Entity File Number	001-36829
Entity Registrant Name	Rocket Pharmaceuticals, Inc.
Entity Central Index Key	0001281895
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	04-3475813
Entity Address, Address Line One	9 Cedarbrook Drive
Entity Address, City or Town	Cranbury
Entity Address, State or Province	NJ
Entity Address, Postal Zip Code	08512
City Area Code	609
Local Phone Number	659-8001
Title of 12(b) Security	Common Stock, $0.01 par value per share
Trading Symbol	RCKT
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		91,157,085

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Current assets:
Cash and cash equivalents	$ 65,599	$ 55,904
Investments	170,063	317,271
Prepaid expenses and other current assets	6,092	5,047
Total current assets	241,754	378,222
Property and equipment, net	38,514	39,172
Goodwill	39,154	39,154
Intangible assets	25,150	25,150
Restricted cash	1,362	1,372
Deposits	503	533
Investments	0	34,320
Operating lease right-of-use assets, net	4,349	3,901
Finance lease right-of-use asset, net	42,902	44,517
Total assets	393,688	566,341
Current liabilities:
Accounts payable and accrued expenses	37,133	45,789
Operating lease liabilities, current	1,005	925
Finance lease liability, current	1,842	1,791
Total current liabilities	39,980	48,505
Operating lease liabilities, non-current	3,413	2,973
Finance lease liability, non-current	19,382	19,353
Other liabilities	1,142	2,936
Total liabilities	63,917	73,767
Commitments and contingencies (Note 13)
Stockholders' equity:
Common stock, $0.01 par value, 180,000,000 shares authorized; 91,116,692 and 90,282,267 shares issued and outstanding at September 30, 2024 and December 31, 2023, respectively	911	903
Additional paid-in capital	1,486,436	1,450,722
Accumulated other comprehensive income (loss)	213	319
Accumulated deficit	(1,157,789)	(959,370)
Total stockholders' equity	329,771	492,574
Total liabilities and stockholders' equity	393,688	566,341
Series A Convertible Preferred Shares
Stockholders' equity:
Preferred stock
Series B Convertible Preferred Shares
Stockholders' equity:
Preferred stock

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Sep. 30, 2024	Dec. 31, 2023
Stockholders' equity:
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized (in shares)	5,000,000	5,000,000
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	180,000,000	180,000,000
Common stock, shares issued (in shares)	91,116,692	90,282,267
Common stock, shares outstanding (in shares)	91,116,692	90,282,267
Series A Convertible Preferred Shares
Stockholders' equity:
Preferred stock, shares authorized (in shares)	300,000	300,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Series B Convertible Preferred Shares
Stockholders' equity:
Preferred stock, shares authorized (in shares)	300,000	300,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Consolidated Statements of Operations [Abstract]
Revenue	$ 0	$ 0	$ 0	$ 0
Operating expenses:
Research and development	42,315	46,844	133,887	144,598
General and administrative	27,109	18,585	76,624	51,782
Total operating expenses	69,424	65,429	210,511	196,380
Loss from operations	(69,424)	(65,429)	(210,511)	(196,380)
Interest expense	(471)	(469)	(1,413)	(1,405)
Interest and other income, net	1,327	1,720	6,650	4,474
Accretion of discount on investments, net	1,849	2,279	6,855	7,376
Net loss	$ (66,719)	$ (61,899)	$ (198,419)	$ (185,935)
Net loss per share - basic (in dollars per share)	$ (0.71)	$ (0.75)	$ (2.11)	$ (2.3)
Net loss per share - diluted (in dollars per share)	$ (0.71)	$ (0.75)	$ (2.11)	$ (2.3)
Weighted-average common shares outstanding - basic (in shares)	94,158,491	82,636,120	93,893,729	80,865,658
Weighted-average common shares outstanding - diluted (in shares)	94,158,491	82,636,120	93,893,729	80,865,658

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Consolidated Statements of Comprehensive Loss [Abstract]
Net loss	$ (66,719)	$ (61,899)	$ (198,419)	$ (185,935)
Other comprehensive loss
Net unrealized gain (loss) on investments	431	216	(106)	(151)
Total comprehensive loss	$ (66,288)	$ (61,683)	$ (198,525)	$ (186,086)

Consolidated Statements of Stoc

Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock	Treasury Stock, Common	Additional Paid-In Capital	Accumulated Other Comprehensive Income / (Loss)	Accumulated Deficit
Beginning Balance at Dec. 31, 2022	$ 489,686	$ 791	$ (47)	$ 1,203,074	$ (357)	$ (713,775)
Beginning Balance (in shares) at Dec. 31, 2022		79,123,312
Issuance of common stock pursuant to exercise of stock options	1,114	$ 1		1,113
Issuance of common stock pursuant to exercise of stock options (in shares)		88,429
Issuance of common stock pursuant to vesting of restricted stock units		$ 1		(1)
Issuance of common stock pursuant to vesting of restricted stock units (in shares)		126,060
Issuance of common stock pursuant to exercise of warrants	7	$ 1		6
Issuance of common stock pursuant to exercise of warrant (in shares)		126,093
Issuance of common stock pursuant to the at-the-market offering program, net of issuance costs	17,222	$ 10		17,212
Issuance of common stock pursuant to the at-the-market offering program, net of issuance costs (in shares)		948,300
Unrealized comprehensive gain (loss) on investments	267				267
Stock-based compensation	8,915			8,915
Net loss	(58,335)					(58,335)
Ending Balance at Mar. 31, 2023	458,876	$ 804	(47)	1,230,319	(90)	(772,110)
Ending Balance (in shares) at Mar. 31, 2023		80,412,194
Beginning Balance at Dec. 31, 2022	489,686	$ 791	(47)	1,203,074	(357)	(713,775)
Beginning Balance (in shares) at Dec. 31, 2022		79,123,312
Net loss	(185,935)
Ending Balance at Sep. 30, 2023	541,086	$ 901		1,440,403	(508)	(899,710)
Ending Balance (in shares) at Sep. 30, 2023		90,146,602
Beginning Balance at Mar. 31, 2023	458,876	$ 804	(47)	1,230,319	(90)	(772,110)
Beginning Balance (in shares) at Mar. 31, 2023		80,412,194
Issuance of common stock pursuant to exercise of stock options	182			182
Issuance of common stock pursuant to exercise of stock options (in shares)		48,088
Issuance of common stock pursuant to vesting of restricted stock units		$ 1		(1)
Issuance of common stock pursuant to vesting of restricted stock units (in shares)		61,133
Unrealized comprehensive gain (loss) on investments	(632)				(632)
Stock-based compensation	10,245			10,245
Net loss	(65,701)					(65,701)
Ending Balance at Jun. 30, 2023	402,970	$ 805	(47)	1,240,745	(722)	(837,811)
Ending Balance (in shares) at Jun. 30, 2023		80,521,415
Issuance of common stock, net of issuance costs	188,884	$ 94		188,790
Issuance of common stock, net of issuance costs (in shares)		9,453,418
Issuance of common stock pursuant to exercise of stock options	545	$ 1		544
Issuance of common stock pursuant to exercise of stock options (in shares)		56,811
Issuance of common stock pursuant to vesting of restricted stock units		$ 1		(1)
Issuance of common stock pursuant to vesting of restricted stock units (in shares)		114,958
Sale of treasury stock	56		$ 47	9
Unrealized comprehensive gain (loss) on investments	214				214
Stock-based compensation	10,316			10,316
Net loss	(61,899)					(61,899)
Ending Balance at Sep. 30, 2023	541,086	$ 901		1,440,403	(508)	(899,710)
Ending Balance (in shares) at Sep. 30, 2023		90,146,602
Beginning Balance at Dec. 31, 2023	492,574	$ 903		1,450,722	319	(959,370)
Beginning Balance (in shares) at Dec. 31, 2023		90,282,267
Issuance of common stock pursuant to exercise of stock options	1,184			1,184
Issuance of common stock pursuant to exercise of stock options (in shares)		73,745
Issuance of common stock pursuant to vesting of restricted stock units		$ 3		(3)
Issuance of common stock pursuant to vesting of restricted stock units (in shares)		290,578
Unrealized comprehensive gain (loss) on investments	(454)				(454)
Stock-based compensation	10,252			10,252
Net loss	(62,054)					(62,054)
Ending Balance at Mar. 31, 2024	441,502	$ 906		1,462,155	(135)	(1,021,424)
Ending Balance (in shares) at Mar. 31, 2024		90,646,590
Beginning Balance at Dec. 31, 2023	492,574	$ 903		1,450,722	319	(959,370)
Beginning Balance (in shares) at Dec. 31, 2023		90,282,267
Net loss	(198,419)
Ending Balance at Sep. 30, 2024	329,771	$ 911		1,486,436	213	(1,157,789)
Ending Balance (in shares) at Sep. 30, 2024		91,116,692
Beginning Balance at Mar. 31, 2024	441,502	$ 906		1,462,155	(135)	(1,021,424)
Beginning Balance (in shares) at Mar. 31, 2024		90,646,590
Issuance of common stock pursuant to exercise of stock options	1,530	$ 2		1,528
Issuance of common stock pursuant to exercise of stock options (in shares)		159,355
Issuance of common stock pursuant to vesting of restricted stock units		$ 2		(2)
Issuance of common stock pursuant to vesting of restricted stock units (in shares)		150,668
Unrealized comprehensive gain (loss) on investments	(83)				(83)
Stock-based compensation	11,332			11,332
Net loss	(69,646)					(69,646)
Ending Balance at Jun. 30, 2024	384,635	$ 910		1,475,013	(218)	(1,091,070)
Ending Balance (in shares) at Jun. 30, 2024		90,956,613
Issuance of common stock pursuant to exercise of stock options	176			176
Issuance of common stock pursuant to exercise of stock options (in shares)		13,108
Issuance of common stock pursuant to vesting of restricted stock units		$ 1		(1)
Issuance of common stock pursuant to vesting of restricted stock units (in shares)		146,971
Unrealized comprehensive gain (loss) on investments	431				431
Stock-based compensation	11,248			11,248
Net loss	(66,719)					(66,719)
Ending Balance at Sep. 30, 2024	$ 329,771	$ 911		$ 1,486,436	$ 213	$ (1,157,789)
Ending Balance (in shares) at Sep. 30, 2024		91,116,692

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023
Operating activities:
Net loss	$ (198,419)	$ (185,935)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization of property and equipment	5,399	3,548
Amortization of finance lease right of use asset	1,615	1,615
Impairment of acquired intangible asset	0	574
Write down of property and equipment, net	0	291
Stock-based compensation	32,832	29,476
Accretion of discount on investments, net	(6,845)	(7,076)
Changes in operating assets and liabilities:
Prepaid expenses and other assets	(1,015)	(1,962)
Accounts payable and accrued expenses	5,293	(5,611)
Operating lease liabilities and right of use assets, net	72	120
Finance lease liability	80	109
Other liabilities	(1,794)	(726)
Net cash used in operating activities	(162,782)	(165,577)
Investing activities:
Purchases of investments	(121,841)	(182,418)
Proceeds from maturities of investments	296,971	236,982
Payments made to acquire right of use asset	0	(36)
Purchases of property and equipment	(5,553)	(11,789)
Net cash provided by investing activities	169,577	42,739
Financing activities:
Issuance of common stock, pursuant to exercise of stock options	2,890	1,841
Issuance of common stock, pursuant to sale of treasury stock	0	56
Issuance of common stock, pursuant to exercise of warrants	0	7
Net cash provided by financing activities	2,890	208,010
Net change in cash, cash equivalents and restricted cash	9,685	85,172
Cash, cash equivalents and restricted cash at beginning of period	57,276	141,857
Cash, cash equivalents and restricted cash at end of period	66,961	227,029
Supplemental disclosure of non-cash financing and investing activities:
Accrued purchases of property and equipment, ending balance	265	1,670
Operating lease liabilities	1,134	2,813
Unrealized loss on investments	(106)	(151)
Public Offering
Financing activities:
Issuance of common stock, net of issuance costs	0	188,884
At-the-Market Offering
Financing activities:
Issuance of common stock, net of issuance costs	$ 0	$ 17,222

Pay vs Performance Disclosure

Pay vs Performance Disclosure - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2024	Jun. 30, 2024	Mar. 31, 2024	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Sep. 30, 2024	Sep. 30, 2023
Pay vs Performance Disclosure
Net Income (Loss)	$ (66,719)	$ (69,646)	$ (62,054)	$ (61,899)	$ (65,701)	$ (58,335)	$ (198,419)	$ (185,935)

Insider Trading Arrangements

Insider Trading Arrangements	3 Months Ended
	Sep. 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

Nature of Business

Nature of Business	9 Months Ended
	Sep. 30, 2024
Nature of Business [Abstract]
Nature of Business	1. Nature of Business Rocket Pharmaceuticals, Inc. is a fully integrated, late-stage biotechnology company focused on the development of first, only and best in class gene therapies, with direct on-target mechanism of action and clear clinical endpoints, for rare and devastating diseases. The Company has three clinical-stage ex vivo lentiviral vector programs, which include programs for: • Fanconi Anemia, a genetic defect in the bone marrow that reduces production of blood cells or promotes the production of faulty blood cells (RP-L102); • Leukocyte Adhesion Deficiency-I, a genetic disorder that causes the immune system to malfunction (RP-L201); and • Pyruvate Kinase Deficiency, a red blood cell autosomal recessive disorder that results in chronic non-spherocytic hemolytic anemia (RP-L301). In September 2023, the FDA accepted the BLA and granted priority review for RP-L201 for the treatment of severe LAD-I. On June 28, 2024, the Company announced that the FDA had issued a CRL in response to the BLA wherein the FDA requested limited additional CMC information to complete its review. The Company is in the process of providing the additional requested information and approval is expected in 2025. Treatments in the FA Phase 2 studies were completed in 2023 and submission of a BLA on a rolling review basis was initiated on September 26, 2024. In April 2024, the EMA accepted our MAA for RP-L102. Additional work on a gene therapy program for the less common FA subtypes C and G is ongoing. The Company also has two clinical stage and one pre-clinical stage in vivo adeno-associated virus programs, which include programs for: • Danon Disease, a multi-organ lysosomal-associated disorder leading to early death due to heart failure. The DD program is currently in an ongoing Phase 2 trial (RP-A501); • Plakophilin-2 Arrhythmogenic Cardiomyopathy, an inheritable cardiac disorder that is characterized by a progressive loss of cardiac muscle mass, severe right ventricular dilation, dysplasia, fibrofatty replacement of the myocardium and a high propensity to arrhythmias and sudden death (RP-A601); and • BAG3 Dilated Cardiomyopathy, which is the most common form of cardiomyopathy and is characterized by progressive thinning of the walls of the heart resulting in enlarged heart chambers that are unable to pump blood. The Company utilizes recombinant AAV9-based gene therapy designed to slow or halt progression of BAG3-DCM. In September 2023, the Company announced its alignment with the FDA on its pivotal study design for RP-A501 in Danon Disease and completion of enrollment in this study was announced in September 2024, dosing and follow-up is ongoing. The Company has received FDA clearance of an IND for RP-A601, and has initiated a Phase 1 study for this program. For the BAG3 program, nonclinical and IND enabling studies are ongoing. Submission of the IND is anticipated in the first half of 2025. The Company has global commercialization and development rights to all of these product candidates under royalty-bearing license agreements.

Risks and Liquidity

Risks and Liquidity	9 Months Ended
	Sep. 30, 2024
Risks and Liquidity [Abstract]
Risks and Liquidity	2. Risks and Liquidity The Company has not generated any revenue and has incurred losses since inception. Operations of the Company are subject to certain risks and uncertainties, including, among others, uncertainty of drug candidate development, technological uncertainty, uncertainty regarding patents and proprietary rights, having no commercial manufacturing experience, marketing or sales capability or experience, dependency on key personnel, compliance with government regulations and the need to obtain additional financing. Drug candidates currently under development will require significant additional research and development efforts, including extensive preclinical and clinical testing and regulatory approval, prior to commercialization. These efforts require significant amounts of additional capital, adequate personnel infrastructure, and extensive compliance-reporting capabilities. The Company’s product candidates are in the development and clinical stage. There can be no assurance that the Company’s research and development will be successfully completed, that adequate protection for the Company’s intellectual property will be obtained, that any products developed will obtain necessary government approval or that any approved products will be commercially viable. Even if the Company’s product development efforts are successful, it is uncertain when, if ever, the Company will generate significant revenue from product sales. The Company operates in an environment of rapid change in technology and substantial competition from pharmaceutical and biotechnology companies. The Company’s consolidated financial statements have been prepared on the basis of continuity of operations, realization of assets and the satisfaction of liabilities in the ordinary course of business. The Company has experienced negative cash flows from operations and had an accumulated deficit of $ 1.16 billion as of September 30, 2024. As of September 30, 2024, the Company had $ 235.7 million of cash, cash equivalents and investments. The Company expects that in accordance with the current operating plan, which includes cost optimization and savings, such resources will be sufficient to fund the Company’s operating expenses and capital expenditure requirements into 2026. On February 28, 2022, the Company entered into a sales agreement (the “Sales Agreement”), with Cowen, with respect to an at-the-market offering program pursuant to which the Company may offer and sell, from time to time at its sole discretion, shares of its common stock, par value $ 0.01 per share, having an aggregate offering price of up to $ 200 million (the “Shares”) through Cowen as its sales agent. On September 12, 2023, the Company and Cowen entered into an amendment (the “Amended Sales Agreement”) pursuant to which the aggregate offering amount available under the at-the-market offering program was reduced to $ 180.0 million. Through September 30, 2024 , the Company has sold 4.2 million shares of common stock for net proceeds of $ 63.8 million pursuant to the at-the-market offering program (see Note 8 “Stockholders’ Equity”). The Company did not sell any shares under the at-the-market offering program during the nine months ended September 30, 2024. In the longer term, the future viability of the Company is dependent on its ability to generate cash from operating activities or to raise additional capital to finance its operations. The Company’s failure to raise capital as and when needed could have a negative impact on its financial condition and ability to pursue its business strategies.

Basis of Presentation, Principl

Basis of Presentation, Principles of Consolidation and Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2024
Basis of Presentation, Principles of Consolidation and Summary of Significant Accounting Policies [Abstract]
Basis of Presentation, Principles of Consolidation and Summary of Significant Accounting Policies	3. Basis of Presentation, Principles of Consolidation and Summary of Significant Accounting Policies Basis of Presentation The accompanying unaudited interim consolidated financial statements should be read in conjunction with the Company’s consolidated financial statements for the year ended December 31, 2023 included in the Annual Report on Form 10-K filed with the Securities and Exchange Commission on February 27, 2024. The unaudited interim consolidated financial statements have been prepared on the same basis as the audited annual financial statements and, in the opinion of management, reflect all adjustments, which include only normal recurring adjustments, necessary for the fair statement of the Company’s consolidated financial position as of September 30, 2024 and the results of its operations and its cash flows for the nine months ended September 30, 2024. The financial data and other information disclosed in these consolidated notes related to the three and nine months ended September 30, 2024 and 2023 are unaudited. The results for the three and nine months ended September 30, 2024 are not necessarily indicative of results to be expected for the year ending December 31, 2024 and any other interim periods or any future year or period. Significant Accounting Policies The significant accounting policies used in the preparation of these consolidated financial statements for the three and nine months ended September 30, 2024 are consistent with those disclosed in Note 3 to the consolidated financial statements in the 2023 Form 10-K with the most significant policies also being listed here. Principles of Consolidation The consolidated financial statements represent the consolidation of the accounts of the Company and its subsidiaries in conformity with U.S. GAAP. All intercompany accounts have been eliminated in consolidation. Use of Estimates The preparation of the consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of expenses during the reporting period. Significant estimates and assumptions reflected in these consolidated financial statements include but are not limited to goodwill and intangible asset impairments, the accrual of R&D expenses, and the valuation of equity transactions and stock-based awards. Changes in estimates and assumptions are reflected in reported results in the period in which they become known. Actual results could differ from those estimates. Cash, Cash Equivalents and Restricted Cash Cash, cash equivalents and restricted cash consists of bank deposits, certificates of deposit and money market accounts with financial institutions. Cash equivalents are carried at cost which approximates fair value due to their short-term nature and which the Company believes do not have a material exposure to credit risk. The Company considers all highly liquid investments with maturities of three months or less from the date of purchase to be cash equivalents. The Company’s cash and cash equivalent accounts, at times, exceed federally insured limits. The Company has not experienced any losses in such accounts. Restricted cash consists of deposits collateralizing letters of credit issued by a bank in connection with the Company’s operating leases (see Note 12 “Leases” for additional disclosures) and a deposit collateralizing a letter of credit issued by a bank supporting the Company’s corporate credit cards. Cash, cash equivalents and restricted cash consist of the following: September 30, 2024 December 31, 2023 Cash and cash equivalents $ 65,599 $ 55,904 Restricted cash 1,362 1,372 Total cash, cash equivalents and restricted cash $ 66,961 $ 57,276 Concentrations of credit risk and off-balance sheet risk Financial instruments that subject the Company to credit risk primarily consist of cash and cash equivalents and available-for-sale securities. The Company maintains its cash and cash equivalent balances with high quality financial institutions and, consequently, the Company believes that such funds are subject to minimal credit risk. The Company’s marketable securities consist of U.S. Treasury Securities and Corporate Bonds. The Company’s investment policy limits the amounts the Company may invest in any one type of investment and requires all investments held by the Company to be at least AA-/Aa3 rated, thereby reducing credit risk exposure. Investments Investments consist of U.S. Treasury Securities and Corporate Bonds. Management determines the appropriate classification of these securities at the time they are acquired and evaluates the appropriateness of such classifications at each balance sheet date. The Company classifies its investments as available-for-sale pursuant to FASB ASC 320, Investments-Debt and Equity Securities. Investments are recorded at fair value, with unrealized gains and losses included as a component of accumulated other comprehensive income (loss) in stockholders’ equity and a component of total comprehensive loss in the consolidated statements of comprehensive loss, until realized. Realized gains and losses are included in investment income on a specific-identification basis. The Company estimates expected credit losses for investments when unrealized losses exist. Unrealized losses that are credit related are recognized in the Company’s Consolidated Statements of Operations and unrealized losses that are not credit related are recognized in accumulated other comprehensive income (loss). For the three and nine months ended September 30, 2024 and 2023, there were no unrealized losses that were credit related. For the three and nine months ended September 30, 2024, there was $ 0.4 million of net unrealized gains on investments and $ 0.1 million of net unrealized losses on investments, respectively. For the three and nine months ended September 30, 2023, there was $ 0.2 million of net unrealized gains on investments and $ 0.2 million of net unrealized losses on investments, respectively. Intangible Assets Intangible assets related to in process research and development projects are considered to be indefinite-lived until the completion or abandonment of the associated R&D efforts. If and when development is complete, which generally occurs if and when regulatory approval to market a product is obtained, the associated assets would be deemed finite-lived and would then be amortized based on their respective estimated useful lives at that point in time. IPR&D intangible assets which are determined to have had a decrease in their fair value are adjusted downward and an expense is recognized in R&D expenses in the Consolidated Statements of Operations. These IPR&D intangible assets are tested at least annually or when a triggering event occurs that could indicate a potential impairment based on indicators including progress of R&D activities, changes in projected development of assets, and changes in regulatory environment and future commercial markets. If a triggering event occurs that would indicate a potential impairment, the Company will perform a quantitative analysis to determine whether it is more likely than not that the fair value is below carrying amount. Fair Value Measurements The Company is required to disclose information on all assets and liabilities reported at fair value that enables an assessment of the inputs used in determining the reported fair values. FASB ASC 820, Fair Value Measurements and Disclosures, establishes a hierarchy of inputs used when available. Observable inputs are inputs that market participants would use in pricing the asset or liability based on market data obtained from sources independent of the Company. Unobservable inputs are inputs that reflect the Company’s assumptions about the inputs that market participants would use in pricing the asset or liability and are developed based on the best information available in the circumstances. The fair value hierarchy applies only to the valuation inputs used in determining the reported fair value of the investments and is not a measure of the investment credit quality. The three levels of the fair value hierarchy are described below: • Level 1 - Valuations based on unadjusted quoted prices in active markets for identical assets or liabilities that the Company has the ability to access at the measurement date. • Level 2 - Valuations based on quoted prices for similar assets or liabilities in markets that are not active or for which all significant inputs are observable, either directly or indirectly. • Level 3 - Valuations that require inputs that reflect the Company’s own assumptions that are both significant to the fair value measurement and unobservable. To the extent that valuation is based on models or inputs that are less observable or unobservable in the market, the determination of fair value requires more judgment. Accordingly, the degree of judgment exercised by the Company in determining fair value is greatest for instruments categorized in 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. The fair value of the Company’s financial instruments, including cash and cash equivalents, restricted cash, deposits, accounts payable and accrued expenses approximate their respective carrying values due to the short-term nature of most of these instruments. Warrants The Company accounts for stock warrants as either equity instruments, liabilities or derivative liabilities in accordance with FASB ASC 480, Distinguishing Liabilities from Equity and/or FASB ASC 815, Derivatives and Hedging, depending on the specific terms of the warrant agreement. Liability-classified warrants are recorded at their estimated fair values at each reporting period until they are exercised, terminated, reclassified or otherwise settled. Changes in the estimated fair value of liability-classified warrants are included in interest and other income in the Company’s Consolidated Statements of Operations. Stock-Based Compensation The Company issues stock-based awards to employees and non-employees, generally in the form of stock options, RSUs and PSUs. The Company measures the compensation expense of employee and non-employee services received in exchange for an award of equity instruments based on the fair value of the award on the grant date. That cost of stock options and RSUs is recognized over the requisite service period of the awards on a straight-line basis with forfeitures recognized as they occur. The vesting condition for PSUs is performance based and the cost of PSUs is recognized when it is likely that the performance goals associated with the PSUs will be achieved and the awards will vest. The Company classifies stock-based compensation expense in its Consolidated Statements of Operations in the same manner in which the award recipient’s payroll costs and services are classified or in which the award recipient’s service payments are classified. Recent Accounting Pronouncements Accounting Pronouncements Not Adopted as of September 30, 2024 ASU 2023-09: Income Taxes Topic 740 - Improvements to Income Tax Disclosures. This update standardizes categories for the effective tax rate reconciliation, requires disaggregation of income taxes and additional income tax-related disclosures. This update is required to be effective for the Company for fiscal periods beginning after December 15, 2024. As this accounting standard is not expected to change the Company’s accounting, it is not expected to have a material impact on the Company’s consolidated financial statements. ASU 2023-07: Segment Reporting Topic 280 - Improvements to Reportable Segment Disclosures. This update requires expanded annual and interim disclosures for significant segment expenses that are regularly provided to the chief operating decision maker and included within each reported measure of segment profit or loss. This update will be effective for fiscal years beginning after December 15, 2023, and is to be applied retrospectively to all periods presented in the financial statements. Early adoption is permitted. As this accounting standard is not expected to change the Company’s accounting, it is not expected to have a material impact on the Company’s consolidated financial statements.

Fair Value of Financial Instrum

Fair Value of Financial Instruments	9 Months Ended
	Sep. 30, 2024
Fair Value of Financial Instruments [Abstract]
Fair Value of Financial Instruments	4. Fair Value of Financial Instruments Items measured at fair value on a recurring basis are the Company’s investments and warrant liability. The following table sets forth the Company’s financial instruments that were measured at fair value on a recurring basis by level within the fair value hierarchy: Fair Value Measurements as of September 30, 2024 Using: Level 1 Level 2 Level 3 Total Assets: Cash equivalents: Money market mutual funds $ 53,993 $ - $ - $ 53,993 53,993 - - 53,993 Investments: U.S. Treasury securities - 157,563 - 157,563 Corporate bonds - 12,500 - 12,500 - 170,063 - 170,063 Total assets $ 53,993 $ 170,063 $ - $ 224,056 Liabilities: Warrant liability $ - $ - $ 1 $ 1 Total liabilities $ - $ - $ 1 $ 1 Fair Value Measurements as of December 31, 2023 Using: Level 1 Level 2 Level 3 Total Assets: Cash equivalents: Money market mutual funds $ 50,737 $ - $ - $ 50,737 U.S. Treasury securities - 2,487 - 2,487 50,737 2,487 - 53,224 Investments: U.S. Treasury securities - 312,696 - 312,696 Corporate bonds - 38,895 - 38,895 - 351,591 - 351,591 Total assets $ 50,737 $ 354,078 $ - $ 404,815 Liabilities: Warrant liability $ - $ - $ 1,876 $ 1,876 Total liabilities $ - $ - $ 1,876 $ 1,876 The Company classifies its money market mutual funds as Level 1 assets under the fair value hierarchy, as these assets have been valued using quoted market prices in active markets without any valuation adjustment. The Company classifies its U.S. Treasury Securities and Corporate Bonds as Level 2 assets as these assets are not traded in an active market and have been valued through a third-party pricing service based on quoted prices for similar assets. The reconciliation of the Company’s warrant liability, which is recorded as part of other liabilities in the Consolidated Balance Sheets, measured at fair value on a recurring basis using unobservable inputs (Level 3) is as follows: Warrant Liability Balance, December 31, 2023 $ 1,876 Fair value adjustments ( 1,875 ) Balance, September 30, 2024 $ 1 The Company utilizes a Black-Scholes option pricing model to value the warrant liability (see Note 10 “Warrants”) at each reporting period, with changes in fair value recognized in the Consolidated Statements of Operations. The estimated fair value of the warrant liability is determined using Level 3 inputs. Inherent in a Black-Scholes option pricing model are assumptions related to expected share-price volatility, expected life, risk-free interest rate and dividend yield. The Company estimates the expected volatility of its common stock based on historical volatility of its common stock, considering the expected remaining life of the warrants. The risk-free interest rate is based on the U.S. Treasury zero-coupon yield curve on the valuation date for a maturity similar to the expected remaining life of the warrants. The expected life of the warrants is assumed to be equivalent to their remaining contractual term. The dividend rate is based on the historical rate, which the Company anticipates will remain at zero . The fair value of the warrant liability has been estimated with the following assumptions: September 30, 2024 December 31, 2023 Stock price $ 18.47 $ 29.50 Exercise price $ 65.23 $ 65.23 Expected volatility 50.38 % 68.83 % Risk-free interest rate 4.33 % 4.70 % Expected dividend yield - - Expected life (years) 0.56 1.31 Fair value per warrant $ 0.00 $ 3.04

Property and Equipment, Net

Property and Equipment, Net	9 Months Ended
	Sep. 30, 2024
Property and Equipment, Net [Abstract]
Property and Equipment, Net	5. Property and Equipment, Net The Company’s property and equipment consisted of the following: September 30, 2024 December 31, 2023 Laboratory equipment $ 32,044 $ 29,232 Machinery and equipment 12,902 12,325 Computer equipment 1,015 244 Furniture and fixtures 2,777 2,777 Leasehold improvements 7,304 6,723 Internal use software 1,903 1,903 57,945 53,204 Less: accumulated depreciation and amortization ( 19,431 ) ( 14,032 ) Total property and equipment, net $ 38,514 $ 39,172 During the three and nine months ended September 30, 2024 , the Company recognized $ 1.9 million and $ 5.4 million of depreciation and amortization expense, respectively. During the three and nine months ended September 30, 2023 , the Company recognized $ 1.2 million and $ 3.5 million of depreciation and amortization expense, respectively.

Intangible Assets and Goodwill

Intangible Assets and Goodwill	9 Months Ended
	Sep. 30, 2024
Intangible Assets and Goodwill [Abstract]
Intangible Assets and Goodwill	6. Intangible Assets and Goodwill The Company’s indefinite lived intangible assets consist of an acquired IPR&D asset received in the acquisition of Renovacor on December 1, 2022. Intangible assets as of September 30, 2024 and December 31, 2023 are summarized as follows: September 30, 2024 December 31, 2023 Gross carrying value $ 25,150 $ 25,150 Accumulated amortization - - Total intangible assets $ 25,150 $ 25,150 The carrying value of Goodwill as of September 30, 2024 and December 31, 2023 was $ 39.2 million.

Accounts Payable and Accrued Ex

Accounts Payable and Accrued Expenses	9 Months Ended
	Sep. 30, 2024
Accounts Payable and Accrued Expenses [Abstract]
Accounts Payable and Accrued Expenses	7. Accounts Payable and Accrued Expenses The Company’s accounts payable and accrued expenses consisted of the following: September 30, 2024 December 31, 2023 Research and development $ 19,074 $ 13,867 Investment payable - 13,137 Employee compensation 10,316 9,930 Property and equipment 265 1,077 Professional fees 4,708 6,006 Other 2,770 1,772 Total accounts payable and accrued expenses $ 37,133 $ 45,789 The $ 13.1 million investment payable at December 31, 2023 was related to investment purchases of available-for-sale securities in 2023 that settled in 2024.

Stockholders' Equity

Stockholders' Equity	9 Months Ended
	Sep. 30, 2024
Stockholders' Equity [Abstract]
Stockholders' Equity	8. Stockholders’ Equity At-the-Market Offering Program On February 28, 2022, the Company entered into the Sales Agreement with Cowen with respect to an at-the-market offering program pursuant to which the Company may offer and sell, from time to time at its sole discretion, shares through Cowen as its sales agent. The shares to be offered and sold under the Sales Agreement, if any, will be offered and sold pursuant to the Company’s shelf registration statement on Form S-3. The Company filed a prospectus supplement with the SEC on February 28, 2022 in connection with the offer and sale of the shares pursuant to the Sales Agreement. The Company will pay Cowen a cash commission of 3.0 % of gross proceeds from the sale of the shares pursuant to the Sales Agreement. The Company has provided Cowen with customary indemnification and contribution rights. The Company has reimbursed Cowen for certain expenses incurred in connection with the Sales Agreement. On September 12, 2023, the Company and Cowen entered into the Amended Sales Agreement pursuant to which the aggregate offering amount available under the at-the-market offering program was reduced to $ 180.0 million. Through September 30, 2024 , the Company sold 4.2 million shares under the at-the-market offering program for gross proceeds of $ 65.8 million, less commissions of $ 2.0 million for net proceeds of $ 63.8 million. The Company did no t sell any shares under the at-the-market offering program during the nine months ended September 30, 2024 .

Stock-Based Compensation

Stock-Based Compensation	9 Months Ended
	Sep. 30, 2024
Stock-Based Compensation [Abstract]
Stock-Based Compensation	9. Stock-Based Compensation Stock Option Valuation The weighted average assumptions that the Company used in a Black-Scholes pricing model to determine the fair value of stock options granted to employees, non-employees and directors were as follows: Nine Months Ended September 30, 2024 2023 Risk-free interest rate 4.85 % 3.98 % Expected term (in years) 5.82 5.84 Expected volatility 73.70 % 73.35 % Expected dividend yield 0.00 % 0.00 % Exercise price $ 27.24 $ 20.15 Fair value of common stock $ 27.24 $ 20.15 The following table summarizes stock option activity for the nine months ended September 30, 2024: Weighted Weighted Average Average Aggregate Number of Exercise Contractual Intrinsic Shares Price Term (Years) Value Outstanding as of December 31, 2023 14,863,996 $ 15.07 5.16 $ 250,602 Granted 1,725,627 27.24 9.37 Exercised ( 246,208 ) 11.74 3,340 Cancelled or forfeited ( 195,395 ) 26.73 Outstanding as of September 30, 2024 16,148,020 $ 16.28 4.94 $ 104,704 Options vested and exercisable as of September 30, 2024 13,012,785 $ 14.52 3.98 $ 103,807 Options unvested as of September 30, 2024 3,135,235 $ 23.57 8.93 $ 897 The weighted average grant-date fair value per share of stock options granted during the nine months ended September 30, 2024, and 2023 was $ 18.34 and $ 13.32 , respectively. The total fair value of options vested during nine months ended September 30, 2024 and 2023 was $ 23.6 million and $ 26.9 million, respectively. Restricted Stock Units The following table summarizes the Company’s RSU activity for the nine months ended September 30, 2024: Weighted Average Number of Grant Date Shares Fair Value Unvested as of December 31, 2023 1,490,357 $ 18.53 Granted 743,022 27.73 Vested ( 588,217 ) 18.75 Forfeited ( 79,718 ) 20.03 Unvested as of September 30, 2024 1,565,444 $ 22.73 Performance Stock Units The following table summarizes the Company’s PSU activity for nine months ended September 30, 2024: Weighted Average Number of Grant Date Shares Fair Value Unvested as of December 31, 2023 - $ - Granted 156,738 27.93 Vested - - Forfeited ( 34,831 ) 28.71 Unvested as of September 30, 2024 121,907 $ 27.71 PSU vesting and expense recognition is based on achievement of specific performance goals within certain time periods. PSU awards that are not achieved within specific time periods are forfeited. No performance goals were probable of achievement and the time period for one performance goal had expired as of September 30, 2024 . Stock-Based Compensation Expense Stock-based compensation expense recognized by award type was as follows: Three Months Ended September 30, Nine Months Ended September 30, 2024 2023 2024 2023 Stock options $ 7,005 $ 7,482 $ 21,105 $ 21,922 Restricted stock units 4,243 2,834 11,727 7,554 Total stock-based compensation expense $ 11,248 $ 10,316 $ 32,832 $ 29,476 Stock-based compensation expense by classification included within the Consolidated Statements of Operations and Comprehensive Loss was as follows: Three Months Ended September 30, Nine Months Ended September 30, 2024 2023 2024 2023 Research and development $ 4,789 $ 4,673 $ 14,311 $ 13,130 General and administrative 6,459 5,643 18,521 16,346 Total stock-based compensation expense $ 11,248 $ 10,316 $ 32,832 $ 29,476 As of September 30, 2024, the Company had an aggregate of $ 72.0 million of unrecognized stock-based compensation expense related to stock options, RSU and PSU grants. The stock options and RSU grants had an aggregate of $ 68.6 million of unrecognized stock-based compensation expense, which is expected to be recognized over a weighted average period of 1.72 years.

Warrants

Warrants	9 Months Ended
	Sep. 30, 2024
Warrants [Abstract]
Warrants	10. Warrants A summary of the warrants outstanding as of September 30, 2024 is as follows: Exercise Price Outstanding Grant/Assumption Date Expiration Date $ 57.11 603,386 December 21, 2020 December 21, 2030 33.63 301,291 August 9, 2021 August 9, 2031 22.51 153,155 December 17, 2021 December 17, 2031 22.51 153,155 December 17, 2021 December 17, 2031 65.23 617,050 December 1, 2022 April 23, 2025 65.23 760,086 December 1, 2022 December 1, 2026 $ 0.01 3,126,955 September 15, 2023 N/A Total 5,715,078 There were no changes in warrants to purchase common stock for the nine months ended September 30, 2024 . Warrants Issued in Public Offering On September 15, 2023, the Company completed a public offering that included pre-funded warrants to purchase 3,126,955 shares of common shares at a price of $ 0.01 per share (see Note 16 “Related Party Transactions”). Assumed Renovacor Public Warrants In conjunction with the acquisition of Renovacor, Rocket assumed pre-acquisition public warrants (“Public Warrants”) that were converted into Rocket warrants with a right to purchase 760,086 of Rocket common shares at an exercise price of $ 65.23 per share. The Company determined that the Public Warrants met all of the criteria for equity classification. Accordingly, upon closing of the acquisition, the Public Warrants were recorded as a component of additional paid-in capital of $ 3.4 million. Assumed Renovacor Private Warrants In conjunction with the acquisition of Renovacor, Rocket assumed pre-acquisition private warrants (“Private Warrants”) that were converted into Rocket warrants with a right to purchase 617,050 of Rocket common shares at an exercise price of $ 65.23 per share. The Company determined that the Private Warrants did not meet all of the criteria for equity classification. Accordingly, the Company classifies the Private Warrants as derivative liabilities in its Consolidated Balance Sheets. The Company measures the fair value of the warrants at the end of each reporting period and recognizes changes in the fair value from the prior period in the Company’s operating results for the current period. See Note 4 “Fair Value of Financial Instruments” for discussion of fair value measurement of the warrant liability.

Net Loss Per Share

Net Loss Per Share	9 Months Ended
	Sep. 30, 2024
Net Loss Per Share [Abstract]
Net Loss Per Share	11. Net Loss Per Share Basic and diluted net loss per share attributable to common stockholders was calculated as follows: Three Months Ended September 30, Nine Months Ended September 30, 2024 2023 2024 2023 Numerator: Net loss attributable to common stockholders $ ( 66,719 ) $ ( 61,899 ) $ ( 198,419 ) $ ( 185,935 ) Denominator: Weighted-average common shares outstanding - basic and diluted 94,158,491 82,636,120 93,893,729 80,865,658 Net loss per share attributable to common stockholders - basic and diluted $ ( 0.71 ) $ ( 0.75 ) $ ( 2.11 ) $ ( 2.30 ) For the nine months ended September 30, 2024 , the Company included the 3,126,955 shares of common stock issuable upon the exercise of pre-funded warrants acquired by funds affiliated with RTW in the weighted average shares outstanding as it was determined that these met the definition for equity classification as the holder is only required to pay $ 0.01 per share upon exercise of the pre-funded warrants. The Company excluded the following potential shares of common stock, presented based on amounts outstanding at each period end, from the computation of diluted net loss per share attributable to common stockholders for the periods indicated because including them would have had an anti-dilutive effect: Three and Nine Months Ended September 30, 2024 2023 Warrants exercisable for common shares 2,588,123 2,588,123 Restricted stock units 1,565,444 1,606,104 Performance stock units 121,907 - Options to purchase common shares 16,148,020 14,889,669 Total potential shares excluded from diluted net loss per share 20,423,494 19,083,896

Leases

Leases	9 Months Ended
	Sep. 30, 2024
Leases [Abstract]
Leases	12. Leases Finance Lease The Company has a lease for a facility in Cranbury, New Jersey, consisting of 103,720 square feet of space including areas for offices, process development, research, and development laboratories and 50,000 square feet dedicated to AAV cGMP manufacturing facilities to support the Company’s pipeline (such lease, as amended, the “NJ Lease Agreement”). The NJ Lease Agreement has a 15 -year term from September 1, 2019, with an option to renew for two consecutive five-year renewal terms. Estimated rent payments for the NJ Lease Agreement are $ 1.2 million per annum, payable in monthly installments, depending upon the nature of the leased space, and subject to annual base rent increases of 3 %. The total commitment under the lease is estimated to be approximately $ 29.3 million over the 15 -year term of the lease. The Company paid a cash security deposit of $ 0.3 million to the landlord in connection with the NJ Lease Agreement which has been reflected as part of deposits in the Consolidated Balance Sheets as of September 30, 2024 and December 31, 2023. Operating Leases On June 7, 2018, the Company entered into a three-year lease agreement for office space in the Empire State Building in New York, NY (the “ESB Lease Agreement”). In connection with the ESB Lease Agreement, the Company established an irrevocable standby letter of credit (the “Empire LOC”) for $ 0.8 million. On March 26, 2021, the Company entered into Amendment No. 1 to the ESB Lease Agreement (“ESB Lease Amendment”) that extended the term of the lease agreement to June 30, 2024 , reduced the rent payments going forward, and reduced the Empire LOC to $ 0.8 million. On March 29, 2024, the Company entered into Amendment No. 2 to the ESB Lease Agreement that extended the term of the lease agreement to July 31, 2027. The Empire LOC serves as the Company’s security deposit on the lease in which the landlord is the beneficiary and expires September 30, 2027 . The Company has a certificate of deposit of $ 0.8 million with a bank as collateral for the Empire LOC which is classified as part of restricted cash in the Consolidated Balance Sheets as of September 30, 2024 and December 31, 2023. On November 15, 2022, the Company entered into a lease agreement with a lease term until October 31, 2024 , for laboratory space in Madrid, Spain. The lease commenced on April 1, 2023 and the Company recognized a right-of-use asset and corresponding lease liability of approximately $ 0.2 million each. On December 1, 2022, in connection with the acquisition of Renovacor, the Company acquired the Renovacor operating leases for space at facilities in Hopewell, New Jersey and Cambridge, Massachusetts with remaining lease terms of approximately 10.3 and 1.3 years, respectively. The Company recognized total right-of-use assets of $ 3.8 million with corresponding total lease liabilities of $ 3.6 million at lease commencement dates. The Company signed an agreement to sublease one of these facilities in January 2024 and intends to sublease the other remaining facilities. Rental income received under the sublease agreement totaled $ 0.1 million and $ 0.3 million for the three and nine months ended September 30, 2024, respectively. Rent expense under operating leases was $ 0.6 million and $ 2.0 million for the three and nine months ended September 30, 2024 . Rent expense under operating leases was $ 0.7 million and $ 1.7 million for the three and nine months ended September 30, 2023, respectively. The total restricted cash balance for the Company’s operating and finance leases as of September 30, 2024 and December 31, 2023 was $ 0.8 million. Operating lease cost was $ 0.3 million and $ 1.0 million for the three and nine months ended September 30, 2024 , respectively. Operating lease cost was $ 0.3 million and $ 1.0 million for the three and nine months ended September 30, 2023, respectively. The following table summarizes lease cost for the nine months ended September 30, 2024 and 2023: Nine Months Ended September 30, Lease cost 2024 2023 Operating lease cost $ 956 $ 1,026 Finance lease cost: Amortization of right of use assets 1,615 1,615 Interest on lease liabilities 1,413 1,405 Total lease cost $ 3,984 $ 4,046 The following table summarizes the future lease payments of the Company’s operating lease liabilities on an undiscounted cash flow basis: Fiscal Year Ending December 31, September 30, 2024 2024 (three months) $ 257 2025 1,001 2026 1,005 2027 759 2028 522 Thereafter 2,420 Total lease payments $ 5,964 Less: interest ( 1,546 ) Total operating lease liabilities $ 4,418 The following table summarizes the future lease payments of the Company’s finance lease liability on an undiscounted cash flow basis: Fiscal Year Ending December 31, September 30, 2024 2024 (three months) $ 457 2025 1,856 2026 1,911 2027 1,969 2028 2,028 Thereafter 41,003 Total lease payments $ 49,224 Less: interest ( 28,000 ) Total finance lease liability $ 21,224 The following table summarizes the operating and financing lease liabilities and right-of-use assets as of September 30, 2024 and December 31, 2023: Leases September 30, 2024 December 31, 2023 Operating right-of-use assets $ 4,349 $ 3,901 Operating current lease liabilities $ 1,005 $ 925 Operating noncurrent lease liabilities 3,413 2,973 Total operating lease liabilities $ 4,418 $ 3,898 Finance right-of-use assets $ 42,902 $ 44,517 Finance current lease liability $ 1,842 $ 1,791 Finance noncurrent lease liability 19,382 19,353 Total finance lease liability $ 21,224 $ 21,144 Nine Months Ended September 30, Other Information 2024 2023 Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows from operating leases $ 829 $ 894 Cash flows from finance lease $ 1,333 $ 1,296 Weighted-average remaining lease term - operating leases 6.7 years 8.0 years Weighted-average remaining lease term - finance lease 19.9 years 20.9 years Weighted-average discount rate - operating leases 8.82 % 8.34 % Weighted-average discount rate - finance lease 8.96 % 8.96 %

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2024
Commitments and Contingencies [Abstract]
Commitments and Contingencies	13. Commitments and Contingencies Litigation From time to time, the Company may be subject to various legal proceedings and claims that arise in the ordinary course of its business activities. Although the results of litigation and claims cannot be predicted with certainty, the Company does not believe it is party to any other claim or litigation the outcome of which, if determined adversely to the Company, would individually or in the aggregate be reasonably expected to have a material adverse effect on its business. Regardless of the outcome, litigation can have an adverse impact on the Company because of defense and settlement costs, diversion of management resources and other factors. Indemnification Arrangements Pursuant to its bylaws and as permitted under Delaware law, the Company has indemnification obligations to directors, officers, employees or agents of the Company or anyone serving in these capacities. The maximum potential amount of future payments the Company could be required to pay is unlimited. The Company has insurance that reduces its monetary exposure and would enable it to recover a portion of any future amounts paid. As a result, the Company believes that the estimated fair value of these indemnification commitments is minimal. Throughout the normal course of business, the Company has agreements with vendors that provide goods and services required by the Company to run its business. In some instances, vendor agreements include language that requires the Company to indemnify the vendor from certain damages caused by the Company’s use of the vendor’s goods and/or services. The Company has insurance that would allow it to recover a portion of any future amounts that could arise from these indemnifications. As a result, the Company believes that the estimated fair value of these indemnification commitments is minimal.

Agreements Related to Intellect

Agreements Related to Intellectual Property	9 Months Ended
	Sep. 30, 2024
Agreements Related to Intellectual Property [Abstract]
Agreements Related to Intellectual Property	14. Agreements Related to Intellectual Property The Company, directly and through its subsidiary Spacecraft Seven, LLC, has various license and research and collaboration arrangements. The transactions principally resulted in the acquisition of rights to intellectual property which is in the preclinical phase and has not been tested for safety or feasibility. In all cases, the Company did not acquire tangible assets, processes, protocols, or operating systems. The Company expenses the acquired intellectual property rights as of the acquisition date on the basis that the cost of intangible assets purchased from others for use in R&D activities has no alternative future uses.

CIRM Grants

CIRM Grants	9 Months Ended
	Sep. 30, 2024
CIRM Grants [Abstract]
CIRM Grants	15. CIRM Grants LAD-I CIRM Grant On April 30, 2019, CIRM awarded the Company up to $ 7.5 million under a CLIN2 grant award to support the clinical development of its LV-based gene therapy, RP-L201. Proceeds from the grant helped fund clinical trial costs as well as manufactured drug product for Phase 1/2 patients enrolled at the U.S. clinical site, University of California, Los Angeles Mattel Children’s Hospital, led by principal investigator Donald Kohn, M.D., UCLA Professor of Microbiology, Immunology and Molecular Genetics, Pediatrics (Hematology/Oncology), Molecular and Medical Pharmacology and member of the Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research at UCLA. As of September 30, 2024 , the Company has received $ 5.9 million in total RP-L201 grants from CIRM. The Company received a final milestone grant of $ 0.05 million on January 2, 2024 and no additional payments are available under the grant awards program. Danon CIRM Grant On August 18, 2024, CIRM awarded the Company up to $ 5.8 million under a CLIN2 grant award to support the clinical development of its AAV-based gene therapy, RP-A501 for the treatment of DD. Proceeds from the grant would help fund clinical trial costs as well as manufactured drug product for Phase 1/2 patients. As of September 30, 2024 , the Company has received an initial RP-A501 grant of $ 1.7 million from CIRM, which was recorded as a reduction of R&D expenses for the RP-A501 program.

Related Party Transactions

Related Party Transactions	9 Months Ended
	Sep. 30, 2024
Related Party Transactions [Abstract]
Related Party Transactions	16. Related Party Transactions In June 2023, the Company entered into a consulting agreement with the spouse of one of the Company’s executive officers for information technology advisory services. The Company incurred expenses of approximately $ 0.002 million for the nine months ended September 30, 2024, relating to services provided under this agreement. In September 2023, in connection with a public offering, the Company sold approximately 3.1 million pre-funded warrants to purchase shares of the Company’s common stock to funds affiliated with RTW, the Company’s largest shareholder (see Note 10 “Warrants”).

401(k) Savings Plan

401(k) Savings Plan	9 Months Ended
	Sep. 30, 2024
401(k) Savings Plan [Abstract]
401(k) Savings Plan	17. 401(k) Savings Plan The Company has a defined contribution savings plan (the “Plan”) under Section 401(k) of the Internal Revenue Code of 1986. This Plan covers substantially all employees who meet minimum age and service requirements and allows participants to defer a portion of their annual compensation on a pre-tax basis. Company contributions to the Plan may be made at the discretion of the Company’s Board of Directors. The Company has elected the safe harbor match of 4 % of employee contributions to the Plan, subject to certain limitations. The Company’s matching contribution for the three and nine months ended September 30, 2024, was $ 0.5 and $ 1.3 million, respectively. The Company’s matching contribution for the three and nine months ended September 30, 2023 , was $ 0.4 and $ 1.1 million, respectively.

Basis of Presentation, Princi_2

Basis of Presentation, Principles of Consolidation and Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2024
Basis of Presentation, Principles of Consolidation and Summary of Significant Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying unaudited interim consolidated financial statements should be read in conjunction with the Company’s consolidated financial statements for the year ended December 31, 2023 included in the Annual Report on Form 10-K filed with the Securities and Exchange Commission on February 27, 2024. The unaudited interim consolidated financial statements have been prepared on the same basis as the audited annual financial statements and, in the opinion of management, reflect all adjustments, which include only normal recurring adjustments, necessary for the fair statement of the Company’s consolidated financial position as of September 30, 2024 and the results of its operations and its cash flows for the nine months ended September 30, 2024. The financial data and other information disclosed in these consolidated notes related to the three and nine months ended September 30, 2024 and 2023 are unaudited. The results for the three and nine months ended September 30, 2024 are not necessarily indicative of results to be expected for the year ending December 31, 2024 and any other interim periods or any future year or period.
Significant Accounting Policies	Significant Accounting Policies The significant accounting policies used in the preparation of these consolidated financial statements for the three and nine months ended September 30, 2024 are consistent with those disclosed in Note 3 to the consolidated financial statements in the 2023 Form 10-K with the most significant policies also being listed here.
Principles of Consolidation	Principles of Consolidation The consolidated financial statements represent the consolidation of the accounts of the Company and its subsidiaries in conformity with U.S. GAAP. All intercompany accounts have been eliminated in consolidation.
Use of Estimates	Use of Estimates The preparation of the consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of expenses during the reporting period. Significant estimates and assumptions reflected in these consolidated financial statements include but are not limited to goodwill and intangible asset impairments, the accrual of R&D expenses, and the valuation of equity transactions and stock-based awards. Changes in estimates and assumptions are reflected in reported results in the period in which they become known. Actual results could differ from those estimates.
Cash, Cash Equivalents and Restricted Cash	Cash, Cash Equivalents and Restricted Cash Cash, cash equivalents and restricted cash consists of bank deposits, certificates of deposit and money market accounts with financial institutions. Cash equivalents are carried at cost which approximates fair value due to their short-term nature and which the Company believes do not have a material exposure to credit risk. The Company considers all highly liquid investments with maturities of three months or less from the date of purchase to be cash equivalents. The Company’s cash and cash equivalent accounts, at times, exceed federally insured limits. The Company has not experienced any losses in such accounts. Restricted cash consists of deposits collateralizing letters of credit issued by a bank in connection with the Company’s operating leases (see Note 12 “Leases” for additional disclosures) and a deposit collateralizing a letter of credit issued by a bank supporting the Company’s corporate credit cards. Cash, cash equivalents and restricted cash consist of the following: September 30, 2024 December 31, 2023 Cash and cash equivalents $ 65,599 $ 55,904 Restricted cash 1,362 1,372 Total cash, cash equivalents and restricted cash $ 66,961 $ 57,276
Concentrations of Credit Risk and Off-balance Sheet Risk	Concentrations of credit risk and off-balance sheet risk Financial instruments that subject the Company to credit risk primarily consist of cash and cash equivalents and available-for-sale securities. The Company maintains its cash and cash equivalent balances with high quality financial institutions and, consequently, the Company believes that such funds are subject to minimal credit risk. The Company’s marketable securities consist of U.S. Treasury Securities and Corporate Bonds. The Company’s investment policy limits the amounts the Company may invest in any one type of investment and requires all investments held by the Company to be at least AA-/Aa3 rated, thereby reducing credit risk exposure.
Investments	Investments Investments consist of U.S. Treasury Securities and Corporate Bonds. Management determines the appropriate classification of these securities at the time they are acquired and evaluates the appropriateness of such classifications at each balance sheet date. The Company classifies its investments as available-for-sale pursuant to FASB ASC 320, Investments-Debt and Equity Securities. Investments are recorded at fair value, with unrealized gains and losses included as a component of accumulated other comprehensive income (loss) in stockholders’ equity and a component of total comprehensive loss in the consolidated statements of comprehensive loss, until realized. Realized gains and losses are included in investment income on a specific-identification basis. The Company estimates expected credit losses for investments when unrealized losses exist. Unrealized losses that are credit related are recognized in the Company’s Consolidated Statements of Operations and unrealized losses that are not credit related are recognized in accumulated other comprehensive income (loss). For the three and nine months ended September 30, 2024 and 2023, there were no unrealized losses that were credit related. For the three and nine months ended September 30, 2024, there was $ 0.4 million of net unrealized gains on investments and $ 0.1 million of net unrealized losses on investments, respectively. For the three and nine months ended September 30, 2023, there was $ 0.2 million of net unrealized gains on investments and $ 0.2 million of net unrealized losses on investments, respectively.
Intangible Assets	Intangible Assets Intangible assets related to in process research and development projects are considered to be indefinite-lived until the completion or abandonment of the associated R&D efforts. If and when development is complete, which generally occurs if and when regulatory approval to market a product is obtained, the associated assets would be deemed finite-lived and would then be amortized based on their respective estimated useful lives at that point in time. IPR&D intangible assets which are determined to have had a decrease in their fair value are adjusted downward and an expense is recognized in R&D expenses in the Consolidated Statements of Operations. These IPR&D intangible assets are tested at least annually or when a triggering event occurs that could indicate a potential impairment based on indicators including progress of R&D activities, changes in projected development of assets, and changes in regulatory environment and future commercial markets. If a triggering event occurs that would indicate a potential impairment, the Company will perform a quantitative analysis to determine whether it is more likely than not that the fair value is below carrying amount.
Fair Value Measurements	Fair Value Measurements The Company is required to disclose information on all assets and liabilities reported at fair value that enables an assessment of the inputs used in determining the reported fair values. FASB ASC 820, Fair Value Measurements and Disclosures, establishes a hierarchy of inputs used when available. Observable inputs are inputs that market participants would use in pricing the asset or liability based on market data obtained from sources independent of the Company. Unobservable inputs are inputs that reflect the Company’s assumptions about the inputs that market participants would use in pricing the asset or liability and are developed based on the best information available in the circumstances. The fair value hierarchy applies only to the valuation inputs used in determining the reported fair value of the investments and is not a measure of the investment credit quality. The three levels of the fair value hierarchy are described below: • Level 1 - Valuations based on unadjusted quoted prices in active markets for identical assets or liabilities that the Company has the ability to access at the measurement date. • Level 2 - Valuations based on quoted prices for similar assets or liabilities in markets that are not active or for which all significant inputs are observable, either directly or indirectly. • Level 3 - Valuations that require inputs that reflect the Company’s own assumptions that are both significant to the fair value measurement and unobservable. To the extent that valuation is based on models or inputs that are less observable or unobservable in the market, the determination of fair value requires more judgment. Accordingly, the degree of judgment exercised by the Company in determining fair value is greatest for instruments categorized in 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. The fair value of the Company’s financial instruments, including cash and cash equivalents, restricted cash, deposits, accounts payable and accrued expenses approximate their respective carrying values due to the short-term nature of most of these instruments.
Warrants	Warrants The Company accounts for stock warrants as either equity instruments, liabilities or derivative liabilities in accordance with FASB ASC 480, Distinguishing Liabilities from Equity and/or FASB ASC 815, Derivatives and Hedging, depending on the specific terms of the warrant agreement. Liability-classified warrants are recorded at their estimated fair values at each reporting period until they are exercised, terminated, reclassified or otherwise settled. Changes in the estimated fair value of liability-classified warrants are included in interest and other income in the Company’s Consolidated Statements of Operations.
Stock-Based Compensation	Stock-Based Compensation The Company issues stock-based awards to employees and non-employees, generally in the form of stock options, RSUs and PSUs. The Company measures the compensation expense of employee and non-employee services received in exchange for an award of equity instruments based on the fair value of the award on the grant date. That cost of stock options and RSUs is recognized over the requisite service period of the awards on a straight-line basis with forfeitures recognized as they occur. The vesting condition for PSUs is performance based and the cost of PSUs is recognized when it is likely that the performance goals associated with the PSUs will be achieved and the awards will vest. The Company classifies stock-based compensation expense in its Consolidated Statements of Operations in the same manner in which the award recipient’s payroll costs and services are classified or in which the award recipient’s service payments are classified.
Recent Accounting Pronouncements	Recent Accounting Pronouncements Accounting Pronouncements Not Adopted as of September 30, 2024 ASU 2023-09: Income Taxes Topic 740 - Improvements to Income Tax Disclosures. This update standardizes categories for the effective tax rate reconciliation, requires disaggregation of income taxes and additional income tax-related disclosures. This update is required to be effective for the Company for fiscal periods beginning after December 15, 2024. As this accounting standard is not expected to change the Company’s accounting, it is not expected to have a material impact on the Company’s consolidated financial statements. ASU 2023-07: Segment Reporting Topic 280 - Improvements to Reportable Segment Disclosures. This update requires expanded annual and interim disclosures for significant segment expenses that are regularly provided to the chief operating decision maker and included within each reported measure of segment profit or loss. This update will be effective for fiscal years beginning after December 15, 2023, and is to be applied retrospectively to all periods presented in the financial statements. Early adoption is permitted. As this accounting standard is not expected to change the Company’s accounting, it is not expected to have a material impact on the Company’s consolidated financial statements.

Basis of Presentation, Princi_3

Basis of Presentation, Principles of Consolidation and Summary of Significant Accounting Policies (Tables)	9 Months Ended
	Sep. 30, 2024
Basis of Presentation, Principles of Consolidation and Summary of Significant Accounting Policies [Abstract]
Cash, Cash Equivalents and Restricted Cash	Restricted cash consists of deposits collateralizing letters of credit issued by a bank in connection with the Company’s operating leases (see Note 12 “Leases” for additional disclosures) and a deposit collateralizing a letter of credit issued by a bank supporting the Company’s corporate credit cards. Cash, cash equivalents and restricted cash consist of the following: September 30, 2024 December 31, 2023 Cash and cash equivalents $ 65,599 $ 55,904 Restricted cash 1,362 1,372 Total cash, cash equivalents and restricted cash $ 66,961 $ 57,276

Fair Value of Financial Instr_2

Fair Value of Financial Instruments (Tables)	9 Months Ended
	Sep. 30, 2024
Fair Value of Financial Instruments [Abstract]
Measured on Recurring Basis	Items measured at fair value on a recurring basis are the Company’s investments and warrant liability. The following table sets forth the Company’s financial instruments that were measured at fair value on a recurring basis by level within the fair value hierarchy: Fair Value Measurements as of September 30, 2024 Using: Level 1 Level 2 Level 3 Total Assets: Cash equivalents: Money market mutual funds $ 53,993 $ - $ - $ 53,993 53,993 - - 53,993 Investments: U.S. Treasury securities - 157,563 - 157,563 Corporate bonds - 12,500 - 12,500 - 170,063 - 170,063 Total assets $ 53,993 $ 170,063 $ - $ 224,056 Liabilities: Warrant liability $ - $ - $ 1 $ 1 Total liabilities $ - $ - $ 1 $ 1 Fair Value Measurements as of December 31, 2023 Using: Level 1 Level 2 Level 3 Total Assets: Cash equivalents: Money market mutual funds $ 50,737 $ - $ - $ 50,737 U.S. Treasury securities - 2,487 - 2,487 50,737 2,487 - 53,224 Investments: U.S. Treasury securities - 312,696 - 312,696 Corporate bonds - 38,895 - 38,895 - 351,591 - 351,591 Total assets $ 50,737 $ 354,078 $ - $ 404,815 Liabilities: Warrant liability $ - $ - $ 1,876 $ 1,876 Total liabilities $ - $ - $ 1,876 $ 1,876
Changes in Level 3 Liabilities Measured at Fair Value	The reconciliation of the Company’s warrant liability, which is recorded as part of other liabilities in the Consolidated Balance Sheets, measured at fair value on a recurring basis using unobservable inputs (Level 3) is as follows: Warrant Liability Balance, December 31, 2023 $ 1,876 Fair value adjustments ( 1,875 ) Balance, September 30, 2024 $ 1
Level 3 Fair Value of the Private Warrants	The fair value of the warrant liability has been estimated with the following assumptions: September 30, 2024 December 31, 2023 Stock price $ 18.47 $ 29.50 Exercise price $ 65.23 $ 65.23 Expected volatility 50.38 % 68.83 % Risk-free interest rate 4.33 % 4.70 % Expected dividend yield - - Expected life (years) 0.56 1.31 Fair value per warrant $ 0.00 $ 3.04

Property and Equipment, Net (Ta

Property and Equipment, Net (Tables)	9 Months Ended
	Sep. 30, 2024
Property and Equipment, Net [Abstract]
Summary of Property and Equipment	The Company’s property and equipment consisted of the following: September 30, 2024 December 31, 2023 Laboratory equipment $ 32,044 $ 29,232 Machinery and equipment 12,902 12,325 Computer equipment 1,015 244 Furniture and fixtures 2,777 2,777 Leasehold improvements 7,304 6,723 Internal use software 1,903 1,903 57,945 53,204 Less: accumulated depreciation and amortization ( 19,431 ) ( 14,032 ) Total property and equipment, net $ 38,514 $ 39,172

Intangible Assets and Goodwill

Intangible Assets and Goodwill (Tables)	9 Months Ended
	Sep. 30, 2024
Intangible Assets and Goodwill [Abstract]
Summary of Intangible Assets	Intangible assets as of September 30, 2024 and December 31, 2023 are summarized as follows: September 30, 2024 December 31, 2023 Gross carrying value $ 25,150 $ 25,150 Accumulated amortization - - Total intangible assets $ 25,150 $ 25,150

Accounts Payable and Accrued _2

Accounts Payable and Accrued Expenses (Tables)	9 Months Ended
	Sep. 30, 2024
Accounts Payable and Accrued Expenses [Abstract]
Schedule of Accounts Payable and Accrued Expenses	The Company’s accounts payable and accrued expenses consisted of the following: September 30, 2024 December 31, 2023 Research and development $ 19,074 $ 13,867 Investment payable - 13,137 Employee compensation 10,316 9,930 Property and equipment 265 1,077 Professional fees 4,708 6,006 Other 2,770 1,772 Total accounts payable and accrued expenses $ 37,133 $ 45,789

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	9 Months Ended
	Sep. 30, 2024
Stock-Based Compensation [Abstract]
Weighted-Average Assumptions for Stock Options	The weighted average assumptions that the Company used in a Black-Scholes pricing model to determine the fair value of stock options granted to employees, non-employees and directors were as follows: Nine Months Ended September 30, 2024 2023 Risk-free interest rate 4.85 % 3.98 % Expected term (in years) 5.82 5.84 Expected volatility 73.70 % 73.35 % Expected dividend yield 0.00 % 0.00 % Exercise price $ 27.24 $ 20.15 Fair value of common stock $ 27.24 $ 20.15
Stock Option Activity	The following table summarizes stock option activity for the nine months ended September 30, 2024: Weighted Weighted Average Average Aggregate Number of Exercise Contractual Intrinsic Shares Price Term (Years) Value Outstanding as of December 31, 2023 14,863,996 $ 15.07 5.16 $ 250,602 Granted 1,725,627 27.24 9.37 Exercised ( 246,208 ) 11.74 3,340 Cancelled or forfeited ( 195,395 ) 26.73 Outstanding as of September 30, 2024 16,148,020 $ 16.28 4.94 $ 104,704 Options vested and exercisable as of September 30, 2024 13,012,785 $ 14.52 3.98 $ 103,807 Options unvested as of September 30, 2024 3,135,235 $ 23.57 8.93 $ 897
RSU Activity	The following table summarizes the Company’s RSU activity for the nine months ended September 30, 2024: Weighted Average Number of Grant Date Shares Fair Value Unvested as of December 31, 2023 1,490,357 $ 18.53 Granted 743,022 27.73 Vested ( 588,217 ) 18.75 Forfeited ( 79,718 ) 20.03 Unvested as of September 30, 2024 1,565,444 $ 22.73
PSU Activity	The following table summarizes the Company’s PSU activity for nine months ended September 30, 2024: Weighted Average Number of Grant Date Shares Fair Value Unvested as of December 31, 2023 - $ - Granted 156,738 27.93 Vested - - Forfeited ( 34,831 ) 28.71 Unvested as of September 30, 2024 121,907 $ 27.71 PSU vesting and expense recognition is based on achievement of specific performance goals within certain time periods. PSU awards that are not achieved within specific time periods are forfeited. No performance goals were probable of achievement and the time period for one performance goal had expired as of September 30, 2024 .
Stock-Based Compensation Expense by Award Type	Stock-based compensation expense recognized by award type was as follows: Three Months Ended September 30, Nine Months Ended September 30, 2024 2023 2024 2023 Stock options $ 7,005 $ 7,482 $ 21,105 $ 21,922 Restricted stock units 4,243 2,834 11,727 7,554 Total stock-based compensation expense $ 11,248 $ 10,316 $ 32,832 $ 29,476
Stock-Based Compensation Expense	Stock-based compensation expense by classification included within the Consolidated Statements of Operations and Comprehensive Loss was as follows: Three Months Ended September 30, Nine Months Ended September 30, 2024 2023 2024 2023 Research and development $ 4,789 $ 4,673 $ 14,311 $ 13,130 General and administrative 6,459 5,643 18,521 16,346 Total stock-based compensation expense $ 11,248 $ 10,316 $ 32,832 $ 29,476

Warrants (Tables)

Warrants (Tables)	9 Months Ended
	Sep. 30, 2024
Warrants [Abstract]
Warrants Outstanding and Changes in Warrants to Purchase Common Stock	A summary of the warrants outstanding as of September 30, 2024 is as follows: Exercise Price Outstanding Grant/Assumption Date Expiration Date $ 57.11 603,386 December 21, 2020 December 21, 2030 33.63 301,291 August 9, 2021 August 9, 2031 22.51 153,155 December 17, 2021 December 17, 2031 22.51 153,155 December 17, 2021 December 17, 2031 65.23 617,050 December 1, 2022 April 23, 2025 65.23 760,086 December 1, 2022 December 1, 2026 $ 0.01 3,126,955 September 15, 2023 N/A Total 5,715,078 There were no changes in warrants to purchase common stock for the nine months ended September 30, 2024 .

Net Loss Per Share (Tables)

Net Loss Per Share (Tables)	9 Months Ended
	Sep. 30, 2024
Net Loss Per Share [Abstract]
Basic and Diluted Net Loss Per Share	Basic and diluted net loss per share attributable to common stockholders was calculated as follows: Three Months Ended September 30, Nine Months Ended September 30, 2024 2023 2024 2023 Numerator: Net loss attributable to common stockholders $ ( 66,719 ) $ ( 61,899 ) $ ( 198,419 ) $ ( 185,935 ) Denominator: Weighted-average common shares outstanding - basic and diluted 94,158,491 82,636,120 93,893,729 80,865,658 Net loss per share attributable to common stockholders - basic and diluted $ ( 0.71 ) $ ( 0.75 ) $ ( 2.11 ) $ ( 2.30 )
Antidilutive Securities Excluded from Computation of Diluted Net Loss Per Share	The Company excluded the following potential shares of common stock, presented based on amounts outstanding at each period end, from the computation of diluted net loss per share attributable to common stockholders for the periods indicated because including them would have had an anti-dilutive effect: Three and Nine Months Ended September 30, 2024 2023 Warrants exercisable for common shares 2,588,123 2,588,123 Restricted stock units 1,565,444 1,606,104 Performance stock units 121,907 - Options to purchase common shares 16,148,020 14,889,669 Total potential shares excluded from diluted net loss per share 20,423,494 19,083,896

Leases (Tables)

Leases (Tables)	9 Months Ended
	Sep. 30, 2024
Leases [Abstract]
Lease Cost	The following table summarizes lease cost for the nine months ended September 30, 2024 and 2023: Nine Months Ended September 30, Lease cost 2024 2023 Operating lease cost $ 956 $ 1,026 Finance lease cost: Amortization of right of use assets 1,615 1,615 Interest on lease liabilities 1,413 1,405 Total lease cost $ 3,984 $ 4,046
Future Lease Payments of Operating Lease Liabilities	The following table summarizes the future lease payments of the Company’s operating lease liabilities on an undiscounted cash flow basis: Fiscal Year Ending December 31, September 30, 2024 2024 (three months) $ 257 2025 1,001 2026 1,005 2027 759 2028 522 Thereafter 2,420 Total lease payments $ 5,964 Less: interest ( 1,546 ) Total operating lease liabilities $ 4,418
Future Lease Payments of Finance Lease Liability	The following table summarizes the future lease payments of the Company’s finance lease liability on an undiscounted cash flow basis: Fiscal Year Ending December 31, September 30, 2024 2024 (three months) $ 457 2025 1,856 2026 1,911 2027 1,969 2028 2,028 Thereafter 41,003 Total lease payments $ 49,224 Less: interest ( 28,000 ) Total finance lease liability $ 21,224
Balance Sheet Information Related to Leases	The following table summarizes the operating and financing lease liabilities and right-of-use assets as of September 30, 2024 and December 31, 2023: Leases September 30, 2024 December 31, 2023 Operating right-of-use assets $ 4,349 $ 3,901 Operating current lease liabilities $ 1,005 $ 925 Operating noncurrent lease liabilities 3,413 2,973 Total operating lease liabilities $ 4,418 $ 3,898 Finance right-of-use assets $ 42,902 $ 44,517 Finance current lease liability $ 1,842 $ 1,791 Finance noncurrent lease liability 19,382 19,353 Total finance lease liability $ 21,224 $ 21,144
Lease Related to Cash Flow Information, Lease Term and Discount Rate	Nine Months Ended September 30, Other Information 2024 2023 Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows from operating leases $ 829 $ 894 Cash flows from finance lease $ 1,333 $ 1,296 Weighted-average remaining lease term - operating leases 6.7 years 8.0 years Weighted-average remaining lease term - finance lease 19.9 years 20.9 years Weighted-average discount rate - operating leases 8.82 % 8.34 % Weighted-average discount rate - finance lease 8.96 % 8.96 %

Nature of Business - Additional

Nature of Business - Additional Information (Details)	9 Months Ended
	Sep. 30, 2024 Program
LV Member
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Number of clinical-stage programs	3
AAV Member
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Number of clinical-stage programs	2
Number of pre clinical-stage programs	1

Risks and Liquidity - Additiona

Risks and Liquidity - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023	Sep. 12, 2023	Feb. 28, 2022
Class of Stock [Line Items]
Accumulated deficit		$ (1,157,789)		$ (959,370)
Cash, cash equivalents and investments		$ 235,700
Shareholders' Equity Disclosure [Abstract]
Common stock, par value (in dollars per share)		$ 0.01		$ 0.01
Common Stock
Shareholders' Equity Disclosure [Abstract]
Common stock shares issued and sold (in shares)	9,453,418
At-the-Market Offering Program
Shareholders' Equity Disclosure [Abstract]
Common stock shares issued and sold (in shares)		0
Net proceeds from offering		$ 0	$ 17,222
At-the-Market Offering Program | Cowen and Company, LLC
Shareholders' Equity Disclosure [Abstract]
Common stock, par value (in dollars per share)						$ 0.01
Common stock shares issued and sold (in shares)		4,200,000
Net proceeds from offering		$ 63,800
At-the-Market Offering Program | Cowen and Company, LLC | Common Stock
Shareholders' Equity Disclosure [Abstract]
Net proceeds from offering		$ 63,800
At-the-Market Offering Program | Cowen and Company, LLC | Maximum
Shareholders' Equity Disclosure [Abstract]
Aggregate offering price					$ 180,000	$ 200,000

Basis of Presentation, Princi_4

Basis of Presentation, Principles of Consolidation and Summary of Significant Accounting Policies - Cash, Cash Equivalents and Restricted Cash (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023	Sep. 30, 2023	Dec. 31, 2022
Cash, Cash Equivalents and Restricted Cash [Abstract]
Cash and cash equivalents	$ 65,599	$ 55,904
Restricted cash	1,362	1,372
Total cash, cash equivalents and restricted cash	$ 66,961	$ 57,276	$ 227,029	$ 141,857

Basis of Presentation, Princi_5

Basis of Presentation, Principles of Consolidation and Summary of Significant Accounting Policies - Investments - Additional Information (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Investments [Abstract]
Net unrealized loss on credit investments	$ 0	$ 0	$ 0	$ 0
Net unrealized gains (losses) on investments	$ 400,000	$ 200,000	$ (106,000)	$ (151,000)

Fair Value of Financial Instr_3

Fair Value of Financial Instruments - Measured on Recurring Basis (Details) - Recurring - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Assets [Abstract]
Cash equivalents	$ 53,993	$ 53,224
Investments	170,063	351,591
Fair value of financial instruments	224,056	404,815
Liabilities [Abstract]
Total liabilities	1	1,876
Warrant Liability
Liabilities [Abstract]
Total liabilities	1	1,876
Money Market Mutual Funds
Assets [Abstract]
Cash equivalents	53,993	50,737
U.S. Treasury securities
Assets [Abstract]
Cash equivalents		2,487
Investments	157,563	312,696
Corporate bonds
Assets [Abstract]
Investments	12,500	38,895
Level 1
Assets [Abstract]
Cash equivalents	53,993	50,737
Investments	0	0
Fair value of financial instruments	53,993	50,737
Liabilities [Abstract]
Total liabilities	0	0
Level 1 | Warrant Liability
Liabilities [Abstract]
Total liabilities	0	0
Level 1 | Money Market Mutual Funds
Assets [Abstract]
Cash equivalents	53,993	50,737
Level 1 | U.S. Treasury securities
Assets [Abstract]
Cash equivalents		0
Investments	0	0
Level 1 | Corporate bonds
Assets [Abstract]
Investments	0	0
Level 2
Assets [Abstract]
Cash equivalents	0	2,487
Investments	170,063	351,591
Fair value of financial instruments	170,063	354,078
Liabilities [Abstract]
Total liabilities	0	0
Level 2 | Warrant Liability
Liabilities [Abstract]
Total liabilities	0	0
Level 2 | Money Market Mutual Funds
Assets [Abstract]
Cash equivalents	0	0
Level 2 | U.S. Treasury securities
Assets [Abstract]
Cash equivalents		2,487
Investments	157,563	312,696
Level 2 | Corporate bonds
Assets [Abstract]
Investments	12,500	38,895
Level 3
Assets [Abstract]
Cash equivalents	0	0
Investments	0	0
Fair value of financial instruments	0	0
Liabilities [Abstract]
Total liabilities	1	1,876
Level 3 | Warrant Liability
Liabilities [Abstract]
Total liabilities	1	1,876
Level 3 | Money Market Mutual Funds
Assets [Abstract]
Cash equivalents	0	0
Level 3 | U.S. Treasury securities
Assets [Abstract]
Cash equivalents		0
Investments	0	0
Level 3 | Corporate bonds
Assets [Abstract]
Investments	$ 0	$ 0

Fair Value of Financial Instr_4

Fair Value of Financial Instruments - Changes in Level 3 Liabilities Measured at Fair Value (Details) - Recurring - Level 3 - Warrant Liability $ in Thousands	9 Months Ended
	Sep. 30, 2024 USD ($)
Changes in Fair Value of Warrant Liabilities [Roll Forward]
Fair value, beginning of period	$ 1,876
Fair value adjustments	(1,875)
Fair value, end of period	$ 1

Fair Value of Financial Instr_5

Fair Value of Financial Instruments - Level 3 Fair Value of the Private Warrants (Details) - Private Warrants	Sep. 30, 2024 USD ($) $ / shares	Dec. 31, 2023 USD ($) $ / shares
Fair Value of the Private Warrants, Assumptions [Abstract]
Term	6 months 21 days	1 year 3 months 21 days
Fair value per warrant (in dollars per share) | $ / shares	$ 0	$ 3.04
Stock Price
Fair Value of the Private Warrants, Assumptions [Abstract]
Measurement input	18.47	29.5
Exercise Price
Fair Value of the Private Warrants, Assumptions [Abstract]
Measurement input	65.23	65.23
Expected Volatility
Fair Value of the Private Warrants, Assumptions [Abstract]
Measurement input	50.38	68.83
Risk-Free Interest Rate
Fair Value of the Private Warrants, Assumptions [Abstract]
Measurement input	4.33	4.7
Expected Dividend Yield
Fair Value of the Private Warrants, Assumptions [Abstract]
Measurement input	0	0

Property and Equipment, Net - S

Property and Equipment, Net - Summary of Property and Equipment (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Property and Equipment [Abstract]
Property and equipment, gross	$ 57,945	$ 53,204
Less: accumulated depreciation and amortization	(19,431)	(14,032)
Total property and equipment, net	38,514	39,172
Laboratory Equipment
Property and Equipment [Abstract]
Property and equipment, gross	32,044	29,232
Machinery and Equipment
Property and Equipment [Abstract]
Property and equipment, gross	12,902	12,325
Computer Equipment
Property and Equipment [Abstract]
Property and equipment, gross	1,015	244
Furniture and Fixtures
Property and Equipment [Abstract]
Property and equipment, gross	2,777	2,777
Leasehold Improvements
Property and Equipment [Abstract]
Property and equipment, gross	7,304	6,723
Internal use Software
Property and Equipment [Abstract]
Property and equipment, gross	$ 1,903	$ 1,903

Property and Equipment, Net - A

Property and Equipment, Net - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Property and Equipment, Net [Abstract]
Depreciation and amortization	$ 1.9	$ 1.2	$ 5.4	$ 3.5

Intangible Assets and Goodwil_2

Intangible Assets and Goodwill - Summary of Intangible Assets (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Intangible Assets, Net [Abstract]
Gross Carrying Value	$ 25,150	$ 25,150
Total intangible assets	$ 25,150	$ 25,150

Intangible Assets and Goodwil_3

Intangible Assets and Goodwill - Additional Information (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Indefinite-Lived Intangible Assets [Line Items]
Goodwill	$ 39,154	$ 39,154

Accounts Payable and Accrued _3

Accounts Payable and Accrued Expenses - Schedule of Accounts Payable and Accrued Expenses (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Accounts Payable and Accrued Expenses [Abstract]
Research and development	$ 19,074	$ 13,867
Investment payable	0	13,137
Employee compensation	10,316	9,930
Property and equipment	265	1,077
Professional fees	4,708	6,006
Other	2,770	1,772
Total accounts payable and accrued expenses	$ 37,133	$ 45,789

Accounts Payable and Accrued _4

Accounts Payable and Accrued Expenses - Additional Information (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Accounts Payable and Accrued Expenses [Abstract]
Investment payable	$ 0	$ 13,137

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Details) - At-the-Market Offering Program - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 12, 2023	Feb. 28, 2022
At-the-Market Offering Program [Abstract]
Issuance of common stock, net of issuance costs (in shares)	0
Net proceeds from offering	$ 0	$ 17,222
Cowen and Company, LLC
At-the-Market Offering Program [Abstract]
Percentage of cash commission				3%
Issuance of common stock, net of issuance costs (in shares)	4,200,000
Gross proceeds, offering amount	$ 65,800
Commissions	2,000
Net proceeds from offering	$ 63,800
Cowen and Company, LLC | Maximum
At-the-Market Offering Program [Abstract]
Aggregate offering price			$ 180,000	$ 200,000

Stock-Based Compensation - Weig

Stock-Based Compensation - Weighted-Average Assumptions for Stock Options (Details) - Employees, Non-employees and Directors - $ / shares	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023
Weighted-Average Assumptions [Abstract]
Risk-free interest rate	4.85%	3.98%
Expected term	5 years 9 months 25 days	5 years 10 months 2 days
Expected volatility	73.70%	73.35%
Expected dividend yield	0%	0%
Exercise price (in dollars per share)	$ 27.24	$ 20.15
Fair value of common stock (in dollars per share)	$ 27.24	$ 20.15

Stock-Based Compensation - Stoc

Stock-Based Compensation - Stock Option Activity (Details) - Employee Stock Option $ / shares in Units, $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2024 USD ($) $ / shares shares	Dec. 31, 2023 USD ($) $ / shares shares
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding [Roll Forward]
Outstanding at beginning of period (in shares) | shares	14,863,996
Granted (in shares) | shares	1,725,627
Exercised (in shares) | shares	(246,208)
Cancelled or forfeited (in shares) | shares	(195,395)
Outstanding at end of period (in shares) | shares	16,148,020	14,863,996
Options vested and exercisable at end of period (in shares) | shares	13,012,785
Options unvested at ending of period (in shares) | shares	3,135,235
Weighted Average Exercise Price [Abstract]
Outstanding at beginning of period (in dollars per share) | $ / shares	$ 15.07
Granted (in dollars per share) | $ / shares	27.24
Exercised (in dollars per share) | $ / shares	11.74
Cancelled or forfeited (in dollars per share) | $ / shares	26.73
Outstanding at end of period (in dollars per share) | $ / shares	16.28	$ 15.07
Options vested and exercisable at end of period (in dollars per share) | $ / shares	14.52
Options unvested at ending (in dollars per share) | $ / shares	$ 23.57
Weighted-Average Remaining Contractual Term [Abstract]
Outstanding	4 years 11 months 8 days	5 years 1 month 28 days
Granted	9 years 4 months 13 days
Options vested and exercisable	3 years 11 months 23 days
Options unvested	8 years 11 months 4 days
Aggregate Intrinsic Value [Abstract]
Outstanding at beginning of period | $	$ 250,602
Exercised | $	3,340
Outstanding at end of period | $	104,704	$ 250,602
Options vested and exercisable | $	103,807
Options unvested | $	$ 897

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023
Employee Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average grant date fair value of shares granted (in dollars per share)	$ 18.34	$ 13.32
Total fair value of options vested	$ 23.6	$ 26.9
Stock Options Performance Stock Units and Restricted Stock Units Grants
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized stock-based compensation expense	72
Stock Options and Restricted Stock Units Grants
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized stock-based compensation expense	$ 68.6
Weighted average period expected to recognize unrecognized share-based compensation cost	1 year 8 months 19 days

Stock-Based Compensation - RSU

Stock-Based Compensation - RSU Activity (Details) - Restricted Stock Units	9 Months Ended
	Sep. 30, 2024 $ / shares shares
Number of Shares [Roll Forward]
Beginning balance (in shares) | shares	1,490,357
Granted (in shares) | shares	743,022
Vested (in shares) | shares	(588,217)
Forfeited (in shares) | shares	(79,718)
Ending balance (in shares) | shares	1,565,444
Weighted Average Grant Date Fair Value [Abstract]
Beginning balance (in dollars per share) | $ / shares	$ 18.53
Granted (in dollars per share) | $ / shares	27.73
Vested (in dollars per share) | $ / shares	18.75
Forfeited (in dollars per share) | $ / shares	20.03
Ending balance (in dollars per share) | $ / shares	$ 22.73

Stock-Based Compensation - PSU

Stock-Based Compensation - PSU Activity (Details) - Performance Stock Units	9 Months Ended
	Sep. 30, 2024 $ / shares shares
Number of Shares [Roll Forward]
Beginning balance (in shares) | shares	0
Granted (in shares) | shares	156,738
Vested (in shares) | shares	0
Forfeited (in shares) | shares	(34,831)
Ending balance (in shares) | shares	121,907
Weighted Average Grant Date Fair Value [Abstract]
Beginning balance (in dollars per share) | $ / shares	$ 0
Granted (in dollars per share) | $ / shares	27.93
Vested (in dollars per share) | $ / shares	0
Forfeited (in dollars per share) | $ / shares	28.71
Ending balance (in dollars per share) | $ / shares	$ 27.71

Stock-Based Compensation - St_2

Stock-Based Compensation - Stock-Based Compensation (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Stock-Based Compensation Expense [Abstract]
Total stock-based compensation expense	$ 11,248	$ 10,316	$ 32,832	$ 29,476
Research and Development
Stock-Based Compensation Expense [Abstract]
Total stock-based compensation expense	4,789	4,673	14,311	13,130
General and Administrative
Stock-Based Compensation Expense [Abstract]
Total stock-based compensation expense	6,459	5,643	18,521	16,346
Employee Stock Option
Stock-Based Compensation Expense [Abstract]
Total stock-based compensation expense	7,005	7,482	21,105	21,922
Restricted Stock Units
Stock-Based Compensation Expense [Abstract]
Total stock-based compensation expense	$ 4,243	$ 2,834	$ 11,727	$ 7,554

Warrants - Summary of Warrants

Warrants - Summary of Warrants Outstanding (Details)	9 Months Ended
	Sep. 30, 2024 $ / shares shares
Warrants [Abstract]
Outstanding (in shares)	5,715,078
57.11
Warrants [Abstract]
Exercise price per share (in dollars per share) | $ / shares	$ 57.11
Outstanding (in shares)	603,386
Grant date	Dec. 21, 2020
Expiration date	Dec. 21, 2030
33.63
Warrants [Abstract]
Exercise price per share (in dollars per share) | $ / shares	$ 33.63
Outstanding (in shares)	301,291
Grant date	Aug. 09, 2021
Expiration date	Aug. 09, 2031
22.51
Warrants [Abstract]
Exercise price per share (in dollars per share) | $ / shares	$ 22.51
Outstanding (in shares)	153,155
Grant date	Dec. 17, 2021
Expiration date	Dec. 17, 2031
22.51
Warrants [Abstract]
Exercise price per share (in dollars per share) | $ / shares	$ 22.51
Outstanding (in shares)	153,155
Grant date	Dec. 17, 2021
Expiration date	Dec. 17, 2031
65.23
Warrants [Abstract]
Exercise price per share (in dollars per share) | $ / shares	$ 65.23
Outstanding (in shares)	617,050
Grant date	Dec. 01, 2022
Expiration date	Apr. 23, 2025
65.23
Warrants [Abstract]
Exercise price per share (in dollars per share) | $ / shares	$ 65.23
Outstanding (in shares)	760,086
Grant date	Dec. 01, 2022
Expiration date	Dec. 01, 2026
0.01
Warrants [Abstract]
Exercise price per share (in dollars per share) | $ / shares	$ 0.01
Outstanding (in shares)	3,126,955
Grant date	Sep. 15, 2023

Warrants - Additional Informati

Warrants - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	Sep. 15, 2023	Sep. 30, 2024	Dec. 31, 2023
Warrants [Abstract]
Additional paid-in capital		$ 1,486,436	$ 1,450,722
Public Warrants
Warrants [Abstract]
Additional paid-in capital		$ 3,400
Public Warrants | Common Stock
Warrants [Abstract]
Warrant to purchase shares of common stock (in shares)		760,086
Warrant to purchase shares of common stock price per share (in dollars per share)		$ 65.23
Private Warrants
Warrants [Abstract]
Warrant to purchase shares of common stock price per share (in dollars per share)		$ 0	$ 3.04
Private Warrants | Common Stock
Warrants [Abstract]
Warrant to purchase shares of common stock (in shares)		617,050
Warrant to purchase shares of common stock price per share (in dollars per share)		$ 65.23
Pre-Funded Warrants | Common Stock
Warrants [Abstract]
Number of stock warrants issued to purchase shares	3,126,955
Warrant to purchase shares of common stock price per share (in dollars per share)	$ 0.01

Net Loss Per Share - Basic and

Net Loss Per Share - Basic and Diluted Net Loss Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Numerator [Abstract]
Net loss attributable to common stockholders	$ (66,719)	$ (61,899)	$ (198,419)	$ (185,935)
Denominator [Abstract]
Weighted-average common shares outstanding - basic (in shares)	94,158,491	82,636,120	93,893,729	80,865,658
Weighted-average common shares outstanding - diluted (in shares)	94,158,491	82,636,120	93,893,729	80,865,658
Net loss per share attributable to common stockholders - basic (in dollars per share)	$ (0.71)	$ (0.75)	$ (2.11)	$ (2.3)
Net loss per share attributable to common stockholders - diluted (in dollars per share)	$ (0.71)	$ (0.75)	$ (2.11)	$ (2.3)

Net Loss Per Share - Additional

Net Loss Per Share - Additional Information (Details) - Pre-Funded Warrants [Member]	9 Months Ended
	Sep. 30, 2024 $ / shares shares
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Shares included in the calculation of EPS | shares	3,126,955
Warrants exercise price per share | $ / shares	$ 0.01

Net Loss Per Share - Antidiluti

Net Loss Per Share - Antidilutive Securities Excluded from Computation of Diluted Net Loss Per Share (Details) - shares	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Weighted Average Number of Shares Outstanding, Diluted, Adjustment [Abstract]
Warrants exercisable for common shares	2,588,123	2,588,123	2,588,123	2,588,123
Restricted stock units	1,565,444	1,606,104	1,565,444	1,606,104
Performance stock units	121,907	0	121,907	0
Options to purchase common shares	16,148,020	14,889,669	16,148,020	14,889,669
Total potential shares excluded from diluted net loss per share	20,423,494	19,083,896	20,423,494	19,083,896

Leases - Finance Lease - Additi

Leases - Finance Lease - Additional Information (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2024 USD ($) ft² Leaseagreement	Dec. 31, 2023 USD ($)
Finance Lease [Abstract]
Total lease payments	$ 49,224
Cash security deposit	$ 503	$ 533
NJ Lease Agreement [Member]
Finance Lease [Abstract]
Area of lease | ft²	103,720
Term of finance lease agreement	15 years
Number of options to renew lease agreement | Leaseagreement	2
Term of renewal of finance lease agreement	5 years
Estimated rent payments	$ 1,200
Percentage of annual increase in base rent	3%
Total lease payments	$ 29,300
Cash security deposit	$ 300
AAV Current Good Manufacturing Practice (cGMP) [Member]
Finance Lease [Abstract]
Area of lease | ft²	50,000

Leases - Operating Leases - Add

Leases - Operating Leases - Additional Information (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
	Mar. 26, 2021	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023	Mar. 31, 2023	Jun. 07, 2018
Operating Leases [Abstract]
Lease expiration date				Oct. 31, 2024
Total right-of-use asset		$ 4,349		$ 4,349		$ 3,901
Total lease liabilities		3,413		3,413		2,973	$ 200
Operating lease cost		300	$ 300	956	$ 1,026
Rent expense under operating leases		600	$ 700	2,000	$ 1,700
Restricted cash		1,362		1,362		1,372
Operating and Finance Leases [Member]
Operating Leases [Abstract]
Restricted cash		800		800		800
Renovacor, Inc. [Member]
Operating Leases [Abstract]
Rental income received under sublease agreements		$ 100		$ 300
Remaining lease term		1 year 3 months 18 days		1 year 3 months 18 days
Total right-of-use asset		$ 3,800		$ 3,800
Total lease liabilities		$ 3,600		$ 3,600
Hopewell, New Jersey and Cambridge [Member] | Renovacor, Inc. [Member]
Operating Leases [Abstract]
Remaining lease term		10 years 3 months 18 days		10 years 3 months 18 days
ESB Lease Agreement [Member]
Operating Leases [Abstract]
Term of lease agreement								3 years
Letter of credit								$ 800
Lease expiration date				Sep. 30, 2027
Certificate of deposit		$ 800		$ 800		$ 800
ESB Lease Agreement Amendment [Member]
Operating Leases [Abstract]
Letter of credit		$ 800		$ 800
Lease expiration date	Jun. 30, 2024

Leases - Leases Cost (Details)

Leases - Leases Cost (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Lease cost [Abstract]
Operating lease cost	$ 300	$ 300	$ 956	$ 1,026
Finance Lease Costs [Abstract]
Amortization of right of use assets			1,615	1,615
Interest on lease liabilities			1,413	1,405
Total lease cost			$ 3,984	$ 4,046

Leases - Future Lease Payments

Leases - Future Lease Payments of Operating Lease Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Future Lease Payments of Operating Lease Liabilities [Abstract]
2024 (three months)	$ 257
2025	1,001
2026	1,005
2027	759
2028	522
Thereafter	2,420
Total lease payments	5,964
Less: interest	(1,546)
Total operating lease liabilities	$ 4,418	$ 3,898

Leases - Future Lease Payment_2

Leases - Future Lease Payments of Finance Lease Liability (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Finance Lease, Liability, to be Paid, Fiscal Year Maturity [Abstract]
2024 (three months)	$ 457
2025	1,856
2026	1,911
2027	1,969
2028	2,028
Thereafter	41,003
Total lease payments	49,224
Less: interest	(28,000)
Total finance lease liability	$ 21,224	$ 21,144

Leases - Balance Sheet Informat

Leases - Balance Sheet Information Related to Leases (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023	Mar. 31, 2023
Lease assets and liabilities [Abstract]
Operating right-of-use assets	$ 4,349	$ 3,901
Operating current lease liabilities	1,005	925
Operating noncurrent lease liabilities	3,413	2,973	$ 200
Total operating lease liabilities	4,418	3,898
Finance right-of-use assets	42,902	44,517
Finance current lease liability	1,842	1,791
Finance noncurrent lease liability	19,382	19,353
Total finance lease liability	$ 21,224	$ 21,144

Leases - Lease Related to Cash

Leases - Lease Related to Cash Flow Information, Lease Term and Discount Rate (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023
Cash Flow, Operating and Financing Activities, Lessee [Abstract]
Operating cash flows from operating leases	$ 829	$ 894
Cash flows from finance lease	$ 1,333	$ 1,296
Weighted-average remaining lease term - operating leases	6 years 8 months 12 days	8 years
Weighted-average remaining lease term - finance lease	19 years 10 months 24 days	20 years 10 months 24 days
Weighted-average discount rate - operating leases	8.82%	8.34%
Weighted-average discount rate - finance lease	8.96%	8.96%

CIRM Grants - Additional Inform

CIRM Grants - Additional Information (Details) - USD ($)	Sep. 30, 2024	Aug. 18, 2024	Jan. 02, 2024	Apr. 30, 2019
LAD-1 CIRM Grant
CIRM Grants [Abstract]
Grant award for clinical development support				$ 7,500,000
Milestone payments received	$ 5,900,000		$ 50,000
Additional payments available under grant awards program	0
Danon Disease CIRM Grant
CIRM Grants [Abstract]
Grant award for clinical development support		$ 5,800,000
Milestone payments received	$ 1,700,000

Related Party Transactions - Ad

Related Party Transactions - Additional Information (Details) - USD ($) $ in Thousands		1 Months Ended	9 Months Ended
	Sep. 15, 2023	Sep. 30, 2023	Sep. 30, 2024
Related Party Transaction [Abstract]
Related party expenses			$ 2
Common Stock | Pre-Funded Warrants
Related Party Transaction [Abstract]
Number of stock warrants issued to purchase shares	3,126,955
Public Offering | Common Stock | Pre-Funded Warrants
Related Party Transaction [Abstract]
Number of stock warrants issued to purchase shares		3,100,000

401(k) Savings Plan - Additiona

401(k) Savings Plan - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
401(k) Savings Plan [Abstract]
Percentage of matching employee contributions			4%
Matching employee contributions	$ 0.5	$ 0.4	$ 1.3	$ 1.1