bluebird bio (BLUE) 10-Q 14 Nov 24 2024 Q3 Quarterly report Financial data

Cover Page

Cover Page - shares	9 Months Ended
	Sep. 30, 2024	Nov. 12, 2024
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2024
Document Transition Report	false
Entity File Number	001-35966
Entity Registrant Name	bluebird bio, Inc.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	13-3680878
Entity Address, Address Line One	455 Grand Union Boulevard
Entity Address, City or Town	Somerville
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	02145
City Area Code	339
Local Phone Number	499-9300
Title of 12(b) Security	Common Stock, $0.01 par value per share
Trading Symbol	BLUE
Security Exchange Name	NASDAQ
Entity Current Reporting Status	No
Entity Interactive Data Current	No
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		194,444,345
Amendment Flag	false
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	Q3
Entity Central Index Key	0001293971
Current Fiscal Year End Date	--12-31

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets (unaudited) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Current assets:
Cash and cash equivalents	$ 70,651	$ 221,755
Prepaid expenses	7,553	14,800
Inventory	53,944	22,919
Due from factor	1,062	560
Receivables and other current assets	17,601	21,651
Total current assets	150,811	281,685
Property, plant and equipment, net	62,593	65,936
Goodwill	5,646	5,646
Intangible assets, net	9,780	10,438
Operating lease right-of-use assets	183,098	201,113
Restricted cash and other non-current assets	53,128	54,343
Total assets	465,056	619,161
Current liabilities:
Accounts payable	24,481	18,498
Due to factor	10,080	2,520
Accrued expenses and other current liabilities	70,179	73,188
Operating lease liability, current portion	24,511	21,202
Financing lease liability, current portion	96,181	84,705
Term loan debt	70,600	0
Total current liabilities	296,032	200,113
Operating lease liability, net of current portion	168,056	186,687
Financing lease liability, net of current portion	5,675	37,732
Other non-current liabilities	1,079	92
Total liabilities	470,842	424,624
Commitments and contingencies (Note 10)
Stockholders’ equity:
Preferred stock, $0.01 par value, 5,000 shares authorized; 0 shares issued and outstanding at September 30, 2024 and December 31, 2023	0	0
Common stock, $0.01 par value, 250,000 shares authorized; 193,917 and 192,772 shares issued and outstanding at September 30, 2024 and December 31, 2023, respectively	1,917	1,905
Additional paid-in capital	4,466,141	4,454,756
Accumulated other comprehensive loss	(1,511)	(1,796)
Accumulated deficit	(4,472,333)	(4,260,328)
Total stockholders’ equity	(5,786)	194,537
Total liabilities and stockholders’ equity	$ 465,056	$ 619,161

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (unaudited) (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
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	250,000,000	250,000,000
Common stock, shares issued (in shares)	193,917,000	192,772,000
Common stock, shares outstanding (in shares)	193,917,000	192,772,000

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations and Comprehensive Loss (unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2024
Revenue:
Product revenue, net	$ 10,612	$ 45,274
Other revenue	0	12
Total revenues	10,612	45,286
Cost of product revenue	11,781	66,591
Gross margin	(1,169)	(21,305)
Operating expenses:
Selling, general and administrative	39,765	136,479
Research and development	23,174	73,408
Restructuring expenses	2,811	2,811
Total operating expenses	65,750	212,698
Gain from sale of priority review voucher, net	0	0
Loss from operations	(66,919)	(234,003)
Interest income	1,640	7,056
Interest expense	(5,778)	(16,875)
Other income, net	10,191	31,782
Loss before income taxes	(60,866)	(212,040)
Income tax (expense) benefit	58	37
Net loss	$ (60,808)	$ (212,003)
Net loss per share - basic (in dollars per share)	$ (0.31)	$ (1.10)
Net loss per share - diluted (in dollars per share)	$ (0.31)	$ (1.10)
Weighted-average number of common shares used in computing net loss per share - basic (in shares)	193,893	193,588
Weighted-average number of common shares used in computing net loss per share - diluted (in shares)	193,893	193,588
Other comprehensive income (loss):
Total other comprehensive income (loss)	$ 611	$ 285
Comprehensive loss	$ (60,197)	$ (211,718)

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Operations and Comprehensive Loss (unaudited) (Parenthetical) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Income Statement [Abstract]
Other comprehensive income (loss), tax	$ 0	$ 0	$ 0	$ 0

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Stockholders' Equity (unaudited) - USD ($) $ in Thousands	Total	Common stock	Additional paid-in capital	Accumulated other comprehensive income (loss)	Accumulated deficit
Beginning balance (in shares) at Dec. 31, 2022		82,923,000
Beginning balance at Dec. 31, 2022	$ 134,333	$ 830	$ 4,185,988	$ (4,070)	$ (4,048,415)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Vesting of restricted stock units (in shares)		382,000
Vesting of restricted stock units	(195)	$ 3	(198)
Exercise of stock options (in shares)		3,000
Exercise of stock options	7		7
Purchase of common stock under employee stock purchase plan (ESPP) (in shares)		62,000
Purchase of common stock under employee stock purchase plan (ESPP)	227	$ 1	226
Issuance of common stock (in shares)		23,000,000
Issuance of common stock	130,291	$ 230	130,061
Stock-based compensation expense	5,843		5,843
Other comprehensive income (loss)	984			984
Net income (loss)	18,930				18,930
Ending balance, shares (in shares) at Mar. 31, 2023		106,370,000
Ending balance at Mar. 31, 2023	290,420	$ 1,064	4,321,927	(3,086)	(4,029,485)
Beginning balance (in shares) at Dec. 31, 2022		82,923,000
Beginning balance at Dec. 31, 2022	134,333	$ 830	4,185,988	(4,070)	(4,048,415)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Other comprehensive income (loss)	1,843
Net income (loss)	(131,091)
Ending balance, shares (in shares) at Sep. 30, 2023		107,022,000
Ending balance at Sep. 30, 2023	152,834	$ 1,071	4,333,496	(2,227)	(4,179,506)
Beginning balance (in shares) at Mar. 31, 2023		106,370,000
Beginning balance at Mar. 31, 2023	290,420	$ 1,064	4,321,927	(3,086)	(4,029,485)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Vesting of restricted stock units (in shares)		65,000
Vesting of restricted stock units	0	$ 1	(1)
Exercise of stock options (in shares)		19,000
Exercise of stock options	77		77
Stock-based compensation expense	6,388		6,388
Other comprehensive income (loss)	722			722
Net income (loss)	(62,789)				(62,789)
Ending balance, shares (in shares) at Jun. 30, 2023		106,454,000
Ending balance at Jun. 30, 2023	234,818	$ 1,065	4,328,391	(2,364)	(4,092,274)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Vesting of restricted stock units (in shares)		566,000
Vesting of restricted stock units	0	$ 6	(6)
Exercise of stock options (in shares)		2,000
Exercise of stock options	8		8
Issuance of common stock	(50)		(50)
Stock-based compensation expense	5,153		5,153
Other comprehensive income (loss)	137			137
Net income (loss)	(87,232)				(87,232)
Ending balance, shares (in shares) at Sep. 30, 2023		107,022,000
Ending balance at Sep. 30, 2023	$ 152,834	$ 1,071	4,333,496	(2,227)	(4,179,506)
Beginning balance (in shares) at Dec. 31, 2023	192,772,000	192,772,000
Beginning balance at Dec. 31, 2023	$ 194,537	$ 1,905	4,454,756	(1,796)	(4,260,328)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Vesting of restricted stock units (in shares)		811,000
Vesting of restricted stock units	0	$ 8	(8)
Issuance of warrants	(2,571)		(2,571)
Stock-based compensation expense	4,054		4,054
Other comprehensive income (loss)	(312)			(312)
Net income (loss)	(69,804)				(69,804)
Ending balance, shares (in shares) at Mar. 31, 2024		193,583,000
Ending balance at Mar. 31, 2024	$ 131,046	$ 1,913	4,461,373	(2,108)	(4,330,132)
Beginning balance (in shares) at Dec. 31, 2023	192,772,000	192,772,000
Beginning balance at Dec. 31, 2023	$ 194,537	$ 1,905	4,454,756	(1,796)	(4,260,328)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of stock options (in shares)	0
Other comprehensive income (loss)	$ 285
Net income (loss)	$ (212,003)
Ending balance, shares (in shares) at Sep. 30, 2024	193,917,000	193,917,000
Ending balance at Sep. 30, 2024	$ (5,786)	$ 1,917	4,466,141	(1,511)	(4,472,333)
Beginning balance (in shares) at Mar. 31, 2024		193,583,000
Beginning balance at Mar. 31, 2024	131,046	$ 1,913	4,461,373	(2,108)	(4,330,132)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Vesting of restricted stock units (in shares)		185,000
Vesting of restricted stock units	0	$ 2	(2)
Purchase of common stock under employee stock purchase plan (ESPP) (in shares)		88,000
Purchase of common stock under employee stock purchase plan (ESPP)	81	$ 1	80
Stock-based compensation expense	3,261		3,261
Other comprehensive income (loss)	(14)			(14)
Net income (loss)	(81,393)				(81,393)
Ending balance, shares (in shares) at Jun. 30, 2024		193,856,000
Ending balance at Jun. 30, 2024	52,981	$ 1,916	4,464,712	(2,122)	(4,411,525)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Vesting of restricted stock units (in shares)		61,000
Vesting of restricted stock units	0	$ 1	(1)
Reclassification of warrants to liability upon modification	(1,945)		(1,945)
Stock-based compensation expense	3,375		3,375
Other comprehensive income (loss)	611			611
Net income (loss)	$ (60,808)				(60,808)
Ending balance, shares (in shares) at Sep. 30, 2024	193,917,000	193,917,000
Ending balance at Sep. 30, 2024	$ (5,786)	$ 1,917	$ 4,466,141	$ (1,511)	$ (4,472,333)

Condensed Consolidated Statem_4

Condensed Consolidated Statements of Cash Flows (unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023
Cash flows from operating activities:
Net loss	$ (212,003)	$ (131,091)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	47,339	19,660
Stock-based compensation expense	9,669	16,013
Noncash research and development expense (finance lease)	0	22,223
Noncash operating lease expense	18,015	23,965
Gain from sale of priority review voucher	0	(92,930)
Change in excess inventory reserve	8,035	9,202
Noncash interest related to debt	1,916	0
Other non-cash items	(14)	100
Gain on foreign currency exchange rates	(86)	(1,062)
Changes in operating assets and liabilities:
Accounts receivable	0	(14,600)
Prepaid expenses and other assets	(47,022)	2,117
Inventory	(38,038)	(26,197)
Accounts payable	6,660	1,712
Accrued expenses and other liabilities	2,986	5,709
Accrued interest payable under finance lease	8,010	3,203
Operating lease liabilities	(15,323)	(18,686)
Deferred revenue	0	(248)
Net cash used in operating activities	(209,856)	(180,910)
Cash flows from investing activities:
Purchase of property, plant and equipment	(2,114)	(2,975)
Purchases of marketable securities	0	(43,297)
Proceeds from previously transferred invoices, net of fees	3,546	0
Proceeds from maturities of marketable securities	0	99,521
Proceeds from sales of marketable securities	0	5,853
Purchase of intangible assets	0	(868)
Proceeds from sale of priority review voucher	0	92,930
Net cash provided by investing activities	1,432	151,164
Cash flows from financing activities:
Proceeds from the issuance of debt, net of fees paid to lender	71,316	0
Proceeds allocated to detachable warrants issued in conjunction with debt	2,669	0
Payments of debt issuance costs	(2,576)	0
Proceeds from exercise of stock options and ESPP contributions	0	93
Proceeds from the transfer of invoices, net of fees	50,646	0
Principal payments on finance leases	(69,576)	(40,299)
Net cash provided by financing activities	52,479	89,670
(Decrease) increase in cash, cash equivalents and restricted cash	(155,945)	59,924
Cash, cash equivalents and restricted cash at beginning of period	274,597	158,445
Cash, cash equivalents and restricted cash at end of period	118,652	218,369
Reconciliation of cash, cash equivalents and restricted cash:
Cash and cash equivalents	70,651	165,347
Restricted cash included in other current assets	4,360	8,885
Restricted cash included in restricted cash and other non-current assets	43,641	44,137
Total cash, cash equivalents and restricted cash	118,652	218,369
Supplemental cash flow disclosures from investing and financing activities:
Purchases of property, plant and equipment included in accounts payable and accrued expenses	31	941
Offering expenses included in accounts payable and accrued expenses	0	248
Right-of-use assets obtained in exchange for operating lease liabilities	0	(708)
Right-of-use assets obtained in exchange for finance lease liabilities	41,893	21,508
Cash paid (refund received) during the period for income taxes	(10)	5
Beneficiary interest obtained in transferred invoices	4,850	0
Derecognition of due to factor liabilities	43,650	0
Private Placement
Cash flows from financing activities:
Proceeds from issuance of common stock	0	(196)
Public Offering
Cash flows from financing activities:
Proceeds from issuance of common stock	$ 0	$ 130,072

Description of the business

Description of the business	9 Months Ended
	Sep. 30, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Description of the business	Description of the business bluebird bio, Inc. (the “Company” or “bluebird”) was incorporated in Delaware on April 16, 1992, and is headquartered in Somerville, Massachusetts. The Company is a biotechnology company committed to researching, developing and commercializing potentially curative gene therapies for severe genetic diseases based on its proprietary lentiviral vector ("LVV") gene addition platform. Since its inception, the Company has devoted substantially all of its resources to its research and development efforts relating to its product candidates, and commercialization of its approved products, including activities to manufacture product candidates, conduct clinical studies of its product candidates, perform preclinical research to identify new product candidates, provide selling, general and administrative support for these operations and market and commercially manufacture and distribute its approved products. The Company’s programs in severe genetic diseases include ZYNTEGLO (betibeglogene autotemcel, also known as beti-cel) as a treatment for β-thalassemia; LYFGENIA (lovotibeglogene autotemcel, also known as lovo-cel) as a treatment for sickle cell disease ("SCD"); and SKYSONA (elivaldogene autotemcel, also known as eli-cel) as a treatment for cerebral adrenoleukodystrophy ("CALD"). On August 17, 2022, ZYNTEGLO was approved by the U.S. Food and Drug Administration ("FDA") for the treatment of adult and pediatric patients with ß-thalassemia who require regular red blood cell transfusions. On September 16, 2022, the FDA granted Accelerated Approval of SKYSONA to slow the progression of neurologic dysfunction in boys 4-17 years of age with early, active CALD. On December 8, 2023, LYFGENIA was approved by the FDA for the treatment of patients 12 years of age or older with sickle cell disease and with a history of vaso-occlusive-events. In August 2023, the Company entered into an Open Market Sales Agreement (the "Sales Agreement") with Jefferies LLC ("Jefferies") to sell shares of the Company’s common stock up to $125.0 million, from time to time, through an “at the market” equity offering program under which Jefferies will act as sales agent. As of September 30, 2024, the Company has made no sales pursuant to the Sales Agreement. In December 2023, the Company entered into an underwriting agreement (the “Underwriting Agreement”) with Goldman Sachs & Co. LLC ("Goldman") and J.P. Morgan Securities LLC, to sell 83.3 million shares of the Company's common stock. The Company received net proceeds of approximately $118.1 million. In March 2024, the Company entered into a five-year term loan facility agreement with Hercules Capital, Inc. to secure debt financing for up to $175.0 million, available in four tranches. This is described in Note 8, Term Loan Debt , in the Notes to Condensed Consolidated Financial Statements appearing elsewhere in this Quarterly Report on Form 10-Q. In September 2024, the Company's board of directors approved a restructuring action (the "Restructuring") following a comprehensive review of the Company's operations, which resulted in a reduction of the Company's workforce by 94 employees, or approximately 25% of employees. The Restructuring is designed to support the Company's commercial focus and reduce its cash operating expenses. Refer to Note 15, Reduction in workforce, for more information on the Restructuring. Since its inception, the Company has incurred significant operating losses and negative operating cash flows. As of September 30, 2024, the Company had an accumulated deficit of $4.5 billion. During the nine months ended September 30, 2024, the Company incurred a net loss of $212.0 million and used $209.9 million of cash in operations. As of September 30, 2024, the Company had cash and cash equivalents of $70.7 million. In accordance with Accounting Standards Codification (“ASC”) 205-40, Going Concern, the Company has evaluated whether there are conditions and events, considered in the aggregate, that raise substantial doubt about the Company’s ability to continue as a going concern within one year after the date the financial statements are issued. This evaluation initially does not take into consideration the potential mitigating effect of management’s plans that have not been fully implemented as of the date the financial statements are issued. When substantial doubt exists under this methodology, management evaluates whether the mitigating effect of its plans sufficiently alleviates substantial doubt about the Company’s ability to continue as a going concern. The mitigating effect of management’s plans, however, is only considered if both (1) it is probable that the plans will be effectively implemented within one year after the date that the financial statements are issued, and (2) it is probable that the plans, when implemented, will mitigate the relevant conditions or events that raise substantial doubt about the entity’s ability to continue as a going concern within one year after the date that these consolidated financial statements are issued. The Company's history of recurring operating losses and negative operating cash flows, its expectation to generate operating losses and negative operating cash flows, its projection that it may not maintain the minimum cash coverage related to the Loan and Security Agreement (the “LSA”), and the need for additional funding to support its planned operations raise substantial doubt regarding the Company’s ability to continue as a going concern for a period of one year after the date that these consolidated financial statements are issued. Management's plans to alleviate the conditions that raise substantial doubt include controlling spending, executing on commercial launch plans, and exploring additional financing options. Management has concluded the likelihood that its plan to successfully obtain sufficient funding from one or more of these sources, or adequately reduce expenditures, while reasonably possible, is less than probable. Accordingly, the Company has concluded that substantial doubt exists about the Company’s ability to continue as a going concern for a period of at least 12 months from the date of issuance of these consolidated financial statements. The Company has based the estimated cash needs on assumptions that may prove to be wrong, and its operating plan may change as a result of many factors currently unknown to it. As a result, the Company could deplete its capital resources sooner than it currently expects. Along with the Company's revenue from product sales, the Company expects to finance its future cash needs through the issuance of equity, or debt, or other alternative means. If the Company is unable to obtain funding on a timely basis, or if revenues from product sales are less than it has projected, the Company may be required to further revise its business plan and strategy, which may result in the Company significantly curtailing, delaying or discontinuing one or more of its research or development programs or the commercialization of any products or may result in the Company being unable to continue or expand its operations or otherwise capitalize on its business opportunities. As a result, the Company's business, financial condition and results of operations could be materially affected. The accompanying financial statements have been prepared on a going concern basis, which contemplates the realization of assets and satisfaction of liabilities in the ordinary course of business. The financial statements do not include any adjustments relating to the recoverability and classification of recorded asset amounts or the amounts and classification of liabilities that might result from the outcome of the uncertainties described above.

Basis of presentation, principl

Basis of presentation, principles of consolidation and significant accounting policies	9 Months Ended
	Sep. 30, 2024
Accounting Policies [Abstract]
Basis of presentation, principles of consolidation and significant accounting policies	Basis of presentation, principles of consolidation and significant accounting policies Basis of presentation The accompanying condensed consolidated financial statements are unaudited and have been prepared by the Company in accordance with accounting principles generally accepted in the United States (“GAAP”). Any reference in these notes to applicable guidance is meant to refer to the authoritative United States GAAP as included in the Accounting Standard Codification (“ASC”) and Accounting Standards Updates (“ASUs”) of the Financial Accounting Standards Board (“FASB”). Certain information and footnote disclosures normally included in the Company’s annual financial statements have been condensed or omitted. These condensed consolidated financial statements, in the opinion of management, reflect all normal recurring adjustments necessary for a fair presentation of the Company’s financial position and results of operations for the interim periods ended September 30, 2024 and 2023. The results of operations for the interim periods are not necessarily indicative of the results of operations to be expected for the full year. These condensed consolidated financial statements should be read in conjunction with the audited consolidated financial statements as of and for the year ended December 31, 2023, and the notes thereto, which are included in the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2023, filed with the Securities and Exchange Commission (the “SEC”) on September 13, 2024 (the "2023 Annual Report on Form 10-K"). Amounts reported are computed based on thousands, except percentages, per share amounts, or as otherwise noted. As a result, certain totals may not sum due to rounding. The accompanying condensed consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries. All intercompany balances and transactions have been eliminated in consolidation. The Company views its operations and manages its business in one operating segment. Restatement of Previously Issued Financial Statements As previously disclosed in the Company's 2023 Annual Report Form 10-K filed with the SEC on September 13, 2024, the Company is restating its previously issued unaudited condensed consolidated financial information for the three and nine month periods ending September 30, 2023 due to multiple prior period misstatements. The accompanying condensed consolidated financial information as of and for the quarter ended September 30, 2023 have been restated in this Quarterly Report on Form 10-Q (see Note 16: Restatement of Previously Issued Financial Statements). In addition, the Company has corrected the accompanying footnotes in connection with the restatement. Significant accounting policies The significant accounting policies used in preparation of these condensed consolidated financial statements for the three and nine months ended September 30, 2024 are consistent with those discussed in Note 3 to the consolidated financial statements included in the Company’s 2023 Annual Report on Form 10-K. Reclassification of Prior Year Presentation Certain prior year amounts have been reclassified to conform to the current year presentation. Specifically, interest expense has been reclassified from interest income to interest expense in the consolidated statement of operations and comprehensive loss. These reclassifications had no effect on the reported results of operations. Use of estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts in the financial statements and accompanying notes. Actual results could materially differ from those estimates. Management considers many factors in selecting appropriate financial accounting policies and controls, and in developing the estimates and assumptions that are used in the preparation of these financial statements. Management must apply significant judgment in this process. In addition, other factors may affect estimates, including: expected business and operational changes, sensitivity and volatility associated with the assumptions used in developing estimates, and whether historical trends are expected to be representative of future trends. The estimation process often may yield a range of potentially reasonable estimates of the ultimate future outcomes and management must select an amount that falls within that range of reasonable estimates. This process may result in actual results differing materially from those estimated amounts used in the preparation of the financial statements. Estimates and judgments are used in the following areas, among others: the alternative future use of assets used in research and development activities, realizability of inventories, future undiscounted cash flows and subsequent fair value estimates used to assess potential and measure any impairment of long-lived assets, including goodwill and intangible assets, and the measurement of right-of-use assets and lease liabilities, gross-to-net revenue calculations, stock-based compensation expense, accrued expenses, income taxes, the assessment of the Company's ability to fund its operations for at least the next twelve months from the date of issuance of these financial statements, and the assessment of the likelihood and magnitude of losses that may be sustained upon resolution of contingencies. Inventory Inventories are stated at the lower of cost or net realizable value under the first-expired, first-out ("FEFO") methodology. Given human gene therapy products are a new and novel category of therapeutics and future economic benefit is not probable until regulatory approval for the product has been obtained, the Company has only considered inventory for capitalization upon regulatory approval. Manufacturing costs incurred prior to regulatory approval for pre-launch inventory that did not qualify for capitalization and clinical manufacturing costs are charged to research and development expense in the Company’s consolidated statements of operations and comprehensive loss as costs are incurred. Additionally, inventory that initially qualifies for capitalization but that may ultimately be used to produce clinical drug product is expensed as research and development expense when it has been designated for the manufacture of clinical drug product. Inventory consists of cell banks, plasmids, LVV, other materials and compounds sourced from third party suppliers and utilized in the manufacturing process, and drug product which has been produced for the treatment of specific patients, that are owned by the Company until infusion. Management periodically reviews inventories for excess or obsolescence, considering factors such as sales forecasts compared to quantities on-hand and firm purchase commitments as well as remaining shelf life of on-hand inventories. The Company writes down its inventory that is in excess, obsolete or otherwise unmarketable to its estimated net realizable value in the period in which the impairment is first identified. Any such adjustments are included as a component of cost of goods sold within cost of product revenue in the Company’s consolidated statements of operations and comprehensive loss. Revenue recognition Under ASC Topic 606, Revenue from Contracts with Customers (“Topic 606”), an entity recognizes revenue when its customer obtains control of promised goods or services, in an amount that reflects the consideration that the entity expects to receive in exchange for those goods or services. To determine revenue recognition for arrangements that an entity determines are within the scope of Topic 606, the entity performs the following five steps: (i) identify the contract(s) with a customer; (ii) identify the performance obligations in the contract; (iii) determine the transaction price, including variable consideration, if any; (iv) allocate the transaction price to the performance obligations in the contract; and (v) recognize revenue when (or as) the entity satisfies a performance obligation. The Company only applies the five-step model to contracts when it is probable that the entity will collect the consideration to which it is entitled in exchange for the goods or services it transfers to the customer. Once a contract is determined to be within the scope of Topic 606, the Company assesses the goods or services promised within each contract and determines those that are performance obligations. Arrangements that include rights to additional goods or services that are exercisable at a customer’s discretion are generally considered options. The Company assesses if these options provide a material right to the customer and if so, they are considered performance obligations. The Company assesses whether each promised good or service is distinct to identify the performance obligations in the contract. This assessment involves subjective determinations and requires management to make judgments about the individual promised goods or services and whether such are separable from the other aspects of the contractual relationship. Promised goods and services are considered distinct provided that: (i) the customer can benefit from the good or service either on its own or together with other resources that are readily available to the customer (that is, the good or service is capable of being distinct) and (ii) the entity’s promise to transfer the good or service to the customer is separately identifiable from other promises in the contract (that is, the promise to transfer the good or service is distinct within the context of the contract). The transaction price is then determined and allocated to the identified performance obligations in proportion to their standalone selling prices (“SSP”) on a relative SSP basis. SSP is determined at contract inception and is not updated to reflect changes between contract inception and when the performance obligations are satisfied. If the consideration promised in a contract includes a variable amount, the Company estimates the amount of consideration to which it will be entitled in exchange for transferring the promised goods or services to a customer. The Company determines the amount of variable consideration by using the expected value method or the most likely amount method. The Company includes the unconstrained amount of estimated variable consideration in the transaction price. The amount included in the transaction price is constrained to the amount for which it is probable that a significant reversal of cumulative revenue recognized will not occur. At the end of each subsequent reporting period, the Company re-evaluates the estimated variable consideration included in the transaction price and any related constraint, and if necessary, adjusts its estimate of the overall transaction price. Any such adjustments are recorded on a cumulative catch-up basis in the adjustment period. In determining the transaction price, the Company adjusts consideration for the effects of the time value of money if the timing of payments provides the Company with a significant benefit of financing. The Company does not assess whether a contract has a significant financing component if the expectation at contract inception is such that the period between payment by the licensees and the transfer of the promised goods or services to the licensees will be one year or less. The Company assessed each of its revenue generating arrangements to determine whether a significant financing component exists and concluded that a significant financing component does not exist in any of its arrangements. The Company then recognizes as revenue the amount of the transaction price that is allocated to the respective performance obligation when (or as) each performance obligation is satisfied, either at a point in time or over time, and if over time recognition is based on the use of an output or input method. Product revenue In 2022, the Company received approval of ZYNTEGLO and SKYSONA from the FDA. In 2023, the Company received approval of LYFGENIA from the FDA. The amount of revenue recognized by the Company is equal to the amount of consideration that is expected to be received from the sale of product to its customers. The Company uses Specialty Distributors ("SD") and Specialty Pharmacies ("SP") to deliver product to the Qualified Treatment Centers ("QTC"). Revenue is only recognized when the performance obligation is satisfied. The Company recognizes revenue upon infusion to the patient. To determine whether a significant reversal will occur in future periods, the Company will assess both the likelihood and magnitude of any such potential reversal of revenue. Gross product revenue is reduced by outcomes-based rebates, other rebates and distributor fees. Rebates expense Rebates are based on contractual arrangements or statutory requirements and include amounts due to Medicaid agencies and third-party payers. These amounts may vary by product and payer. Rebates are estimated primarily based on product sales, including product mix and pricing, historical and estimated payer mix and discount rates, among other inputs, which require significant estimates and judgment. The Company assesses and updates estimates each reporting period to reflect actual claims and other current information. Rebates that are payable to Medicaid agencies and third-party payers are recorded in accrued expenses and other current liabilities on the Company's consolidated balance sheets. Distributor fees The Company pays distribution fees to SDs and SPs in connection with the sales of our product. These distributor fees are based on a contractually determined fixed percentage of sales. Other revenue In 2021, the Company entered into a grant agreement with the Bill and Melinda Gates Foundation. The Company recognizes grant revenue in accordance with ASC 958-605, Revenue Recognition Not-for-Profit Entities , when qualifying costs are incurred and barriers to restriction have been overcome. When grant funds are received after costs have been incurred, the Company records revenue and a corresponding grant receivable. Cash received from grants in advance of incurring qualifying costs is recorded as deferred revenue and recognized as revenue when qualifying costs are incurred. In 2023, the Company ceased further research work. Recent accounting pronouncements In November 2023, the FASB issued ASU 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures to update reportable segment disclosure requirements, primarily through enhanced disclosures about significant segment expenses and information used to assess segment performance and requires companies to disclose all annual disclosures about segments in interim periods. The ASU also requires companies with a single reportable segment to provide all disclosures required by Topic 280 – Segment Reporting. This update is effective beginning with the Company’s 2024 fiscal year annual reporting period and interim periods beginning thereafter. The Company is currently evaluating the impact that the adoption of this standard will have on its consolidated financial statements and disclosures. In December 2023, the FASB issued ASU 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures . This ASU expands disclosures in an entity’s income tax rate reconciliation table and disclosures regarding taxes paid both in the U.S. and foreign jurisdictions. This update is effective beginning with the Company’s 2025 fiscal year annual reporting period. The Company is currently evaluating the impact to its income tax disclosures. In March 2024, the FASB issued ASU 2024-01, Compensation-Stock Compensation (Topic 718): Scope Application of Profits Interest and Similar Awards . This update clarifies the scope of "Profit Interest" and similar awards and adds an illustrative example to the existing ASC 718 standard that includes four fact patterns to demonstrate how an entity should apply the scope guidance in paragraph 718-10-15-3 to determine whether a profits interest award should be accounted for in accordance with Topic 718. The amendments in this ASU are effective for annual periods beginning after December 15, 2024, and interim periods within those annual periods. Early adoption is permitted for interim and annual financial statements not yet issued or made available for issuance. The amendments in this ASU should be applied either (1) retrospectively to all prior periods presented in the financial statements or (2) prospectively to profits interest and similar awards granted or modified on or after the date at which the entity first applies the amendments. The Company is currently evaluating the impact that the adoption of this standard will have on its consolidated financial statements and disclosures. In March 2024, the FASB issued ASU 2024-02 " Codification Improvements—Amendments to Remove References to the Concepts Statements" , which removes various references to concepts statements from the FASB Accounting Standards Codification. This ASU is effective for the Company beginning in the first quarter of fiscal year 2026, with early adoption permitted. The Company expects the new guidance will have an immaterial impact on its consolidated financial statements and intends to adopt the guidance when it becomes effective in the first quarter of fiscal year 2026. In November 2024, the FASB issued ASU 2024-03 "Income Statement—Reporting Comprehensive Income—Expense Disaggregation Disclosures (Subtopic 220-40): Disaggregation of Income Statement Expenses". This ASU requires expanded disclosures of specific income statement expense categories such as cost of product revenue, selling, general, and administrative expenses, and research and development expenses. This update is effective for annual periods beginning after December 15, 2026, and interim periods within fiscal years beginning after December 15, 2027. Early adoption is permitted.

Product revenue and reserves

Product revenue and reserves	9 Months Ended
	Sep. 30, 2024
Revenue from Contract with Customer [Abstract]
Product revenue and reserves	Product revenue and reserves For the three months ended September 30, 2024 and 2023, the Company recorded $10.6 million and $12.3 million, respectively, of product revenue. For the nine months ended September 30, 2024 and 2023, the Company recorded $45.3 million and $21.4 million, respectively, of product revenue. Product revenue by therapy represents: For the three months ended For the nine months ended 2024 2023 2024 2023 ZYNTEGLO $ 5,493 $ 4,851 $ 35,212 $ 9,031 LYFGENIA 2,632 — 2,632 — SKYSONA 2,487 7,430 7,430 12,383 Total product revenue, net $ 10,612 $ 12,281 $ 45,274 $ 21,414 Six individual customers accounted for 84% of product revenue for the nine months ended September 30, 2024 and two individual customer accounted for 89% of product revenue for the nine months ended September 30, 2023. The Company considers there to be revenue concentration risks for customers that represent product revenues that exceed 10% of total product revenue. The concentration of the Company’s product revenue within a particular customer may have a material adverse effect on the Company’s revenue and results of operations if sales with the respective customer experience difficulties. All product revenue during the nine months ended September 30, 2024 and 2023 were within the United States. The following table summarizes an analysis of the change in reserves for gross to net deductions for the periods indicated: Total Balance at December 31, 2023 $ 5,365 Provision for rebates 8,506 Payments/credits — Balance at September 30, 2024 $ 13,871

Fair value measurements

Fair value measurements	9 Months Ended
	Sep. 30, 2024
Fair Value Disclosures [Abstract]
Fair value measurements	Fair value measurements The following table sets forth the Company’s assets and liabilities that are measured at fair value on a recurring basis as of September 30, 2024 and December 31, 2023 (in thousands): Description Total Quoted prices in active markets (Level 1) Significant other observable inputs (Level 2) Significant unobservable inputs (Level 3) September 30, 2024 Assets: Cash and cash equivalents $ 70,651 $ 70,651 $ — $ — Due from factor: Beneficiary interest in factored invoices 1,062 — — 1,062 Other non-current liabilities Warrant liability 987 — — 987 Total $ 72,700 $ 70,651 $ — $ 2,049 December 31, 2023 Assets: Cash and cash equivalents $ 221,755 $ 221,755 $ — $ — Due from factor: Beneficiary interest in factored invoices 560 — — 560 Total $ 222,315 $ 221,755 $ — $ 560 Cash and cash equivalents The Company considers all highly liquid securities with original final maturities of 90 days or less from the date of purchase to be cash equivalents. As of September 30, 2024 and December 31, 2023, cash and cash equivalents comprise funds in cash and money market accounts held at multiple banking and asset management institutions. Factoring agreement Due from factor classified as Level 3 within the valuation hierarchy consists of beneficiary interest in transferred invoices. The Company estimates the fair value of the beneficiary interest based on the estimated cash flows after applying counterparty and credit risk adjustments associated with the factoring agent and distributors, respectively. As of September 30, 2024, no adjustment to the beneficiary interest in invoices sold was deemed an unobservable input and was determined based from ongoing credit evaluations and historical experience with aging of such invoices, among other factors. A significant change to this input could result in a significantly lower fair value measurement. The following table shows a reconciliation of the beginning and ending balances for due from factor Level 3 financial liabilities measured at fair value on a recurring basis for the nine months ended September 30, 2024: For the nine months ended September 30, 2024 Balance at December 31, 2023 $ 560 Beneficiary interest obtained in transferred invoices 4,850 Gross proceeds from previously transferred invoices (4,240) Accrual for factor reserve deficiency (26) Accrual for anticipated loss on sale of invoices (82) Balance at September 30, 2024 $ 1,062 Common stock warrants On March 15, 2024, in connection with its debt issuance (see Note 8, Term loan debt ), the Company issued warrants to a lender to purchase shares of the Company’s common stock at an exercise price of $1.45 per share. On August 13, 2024, the Company amended the exercise price of the warrants to be the lesser of $1.03 per share and the price per share of the Company’s first financing event within six months of August 13, 2024 or February 13, 2025. As a result of the modification, the warrants were reclassified from additional paid-in-capital within stockholders' equity to other non-current liabilities on the condensed consolidated balance sheet at their fair value as of the modification date. The warrants are adjusted to fair value at period end through “other income (expense)” on the condensed consolidated statements of operations and comprehensive loss. The warrants have been recorded at their fair value using the Black-Scholes option-pricing model and the following assumptions: no dividend yield, probability-weighted exercise price ranging between $0.50 and $1.03, stock price of $0.52 per share, expected volatility of 85.7%, risk free rate of 3.7%, and expected term of 7 years, equal to the life of the warrant. The following table shows a reconciliation of the beginning and ending balances for other non-current liabilities due from factor Level 3 financial liabilities measured at fair value on a recurring basis for the nine months ended September 30, 2024: For the nine months ended September 30, 2024 Balance at December 31, 2023 $ — Warrant modification and reclassification to liabilities 2,100 Change in fair value (1,113) Balance at September 30, 2024 $ 987

Inventory

Inventory	9 Months Ended
	Sep. 30, 2024
Inventory Disclosure [Abstract]
Inventory	Inventory Inventory, net, consists of the following (in thousands): As of September 30, 2024 As of December 31, 2023 Raw materials $ 2,965 $ 2,329 Work in progress 48,649 17,375 Finished goods 2,330 3,215 Inventory $ 53,944 $ 22,919

Factoring agreement

Factoring agreement	9 Months Ended
	Sep. 30, 2024
Receivables [Abstract]
Factoring agreement	Factoring agreement The Company sells rights to future revenues associated with invoices issued upon delivery of drug product to QTCs. The Company sells 100% of the invoice, and the upfront purchase price is 90% of the invoice amount. The remaining 10% less applicable fees is payable when the factor receives full payment from the customer. The upfront payments are treated as a short-term liability, presented as due to factor on the Company's consolidated balance sheets until the right to consideration from the customer is deemed unconditional. The remaining invoice amount payable to the Company at infusion is considered a beneficial interest in the factored invoice and represents the extent of our continued involvement in the sale of invoices. Due to Factor For the three and nine months ending September 30, 2024, the Company collected $15.2 million and $50.6 million, respectively, in cash receipts prior to an unconditional right to consideration and derecognized $10.6 million and $43.7 million, respectively, of due to factor amounts as a result of patient drug product infusions. Amounts presented as due to factor on the condensed consolidated balance sheets would be subject to payment based on the repurchase requirements that exist prior to the infusion date in the factoring agreement. Due from Factor For the three and nine months ending September 30, 2024, the company obtained $1.2 million and $4.9 million, respectively, of beneficiary interest in invoices and collected $0.7 million and $3.5 million, respectively, in cash receipts. Uncollected amounts presented as due from factor on the consolidated balance sheets are net of accrued fees of $0.1 million. The maximum loss exposure is $1.2 million at September 30, 2024.

Accrued expenses and other curr

Accrued expenses and other current liabilities	9 Months Ended
	Sep. 30, 2024
Payables and Accruals [Abstract]
Accrued expenses and other current liabilities	Accrued expenses and other current liabilities Accrued expenses and other current liabilities consist of the following (in thousands): As of September 30, 2024 As of December 31, 2023 Accrued CMO and CRO costs $ 21,735 $ 24,824 Accrued employee compensation 15,375 19,972 Accrued rebates 13,998 5,365 Accrued goods and services 1,814 8,391 Accrued professional fees 10,070 2,531 Other sublease rent liability 3,379 3,310 Accrued refund liability — 5,600 Other 3,808 3,195 Total accrued expenses and other current liabilities $ 70,179 $ 73,188

Term loan debt

Term loan debt	9 Months Ended
	Sep. 30, 2024
Debt Disclosure [Abstract]
Term loan debt	Term loan debt 2024 Term Loan On March 15, 2024 (the “Effective Date”), the Company entered into the LSA and a Warrant Agreement (the “Warrant Agreement”) with Hercules Capital and funds managed by Hercules Capital (collectively, “Hercules” or “the lenders”). Under the terms of the LSA, the Company may borrow up to an aggregate principal amount of $175.0 million over the term of the agreement, in four separate tranches (the “Term Loans”) dependent on the achievement of certain milestones. On the Effective Date, the Company drew down the initial $75.0 million of gross proceeds (“Initial Loan”), and paid initial debt issuance costs of $3.5 million, inclusive of legal fees of approximately $2.7 million and the original issuance discount (“OID”) of $0.8 million, or 1% of the drawn amount, in accordance with the terms of the LSA. On August 13, 2024, the Company and Hercules entered into an amendment to the LSA (the “Third Amendment”), pursuant to which the parties agreed to, among other things, revised terms for the availability of the second and third tranches of funding under the LSA and an increase to the minimum cash coverage requirement. In accordance with the Third Amendment, the Company may draw the second tranche of $25.0 million during the period commencing on the date the Company has (x) received at least $75.0 million in gross cash proceeds from qualified financing transactions by December 20, 2024 and (y) completed patient starts (cell collections) for at least 50 LYFGENIA patients by March 31, 2025 or 70 LYFGENIA patients by June 30, 2025 (collectively, the “Tranche 2 Milestone”) and ending on the earlier of (i) the date that is 30 days immediately following achievement of the Tranche 2 Milestone and (ii) July 31, 2025. The Company may draw the third tranche of $25.0 million during the period commencing on the date the Company has (x) received at least $100.0 million in gross cash proceeds from qualified financing transactions by December 20, 2024 or at least $125.0 million by June 30, 2025 and (y) completed 70 drug product deliveries within a given six-month period ending no later than December 31, 2025, at least 40 of which are for LYFGENIA (collectively, the “Tranche 3 Milestone”) and ending on the earlier of (i) the date that is 30 days immediately following the date the Company achieves the Tranche 3 Milestone and (ii) December 31, 2025. The Company may request up to an additional $50.0 million through December 15, 2026 from Hercules (“Tranche 4”). The lenders have no obligation to fund any amounts under Tranche 4 as funding is conditioned on approval by the lenders’ investment committee. The 2024 Term Loan is collateralized by substantially all the Company’s assets. In addition to other covenants, the 2024 Term Loan contains affirmative covenants as well as certain financial covenants, including a minimum cash coverage requirement of 45% of the outstanding principal of the term loan. The Company was in compliance with the minimum cash coverage covenant as of September 30, 2024, but the Company projects that it may not maintain its minimum cash coverage requirement within the next 12 months (see the Company's going concern assessment in Note 1, Description of the business ). As such, the term loan is presented as a current liability as of September 30, 2024. The Term Loans bear both cash interest and paid-in-kind interest (“PIK”). The cash interest is due on the first business day of each month (“Payment Date”) and will be equal to the WSJ prime rate (“prime rate”) plus 1.45% (floored at 9.95%). The PIK interest is fixed at 2.45% and is to be capitalized and added to the outstanding principal on each Payment Date. Unless prepaid by the Company at their discretion, subject to certain prepayment penalties and conditions, the Term Loans are repayable in monthly interest-only payments until April 1, 2027, or April 1, 2028, if the Company has achieved, no later than December 31, 2026, certain financial metrics (the “Performance Milestone”). After the expiration of the interest-only payment period, the Term Loans are repayable in equal monthly payments of principal and accrued interest until maturity. The Term Loans will mature on April 1, 2029. The Company also issued warrants under the Warrant Agreement for the right to purchase shares of the Company’s common stock to Hercules, with the number of shares to be based on the amounts borrowed under the LSA (the “Warrants”). The Warrants are exercisable for a number of shares of common stock equal to the quotient of (i.) 5% times the aggregate original principal of amounts drawn under the LSA divided by (ii.) the exercise price of $1.45 per share. Upon issuance, during the period ended March 31, 2024, the Warrants were recorded at their relative fair value using the Black-Scholes option-pricing model and the following assumptions: no dividend yield, expected volatility of 81.1%, risk free rate of 4.3%, and expected term of 7 years, equal to the life of the warrant. The relative fair value allocated to the initial warrants was $2.7 million, which was classified as additional-paid-in-capital and recorded as a debt discount which will be amortized, together with debt issuance costs, to interest expense using the effective interest method over the life of the loan at an effective interest rate of 15.7%. In connection with the Third Amendment, the Company agreed to amend the exercise price of the Warrants to purchase shares of the Company’s common stock from $1.45 per share to the lesser of the volume weighted average price (“VWAP”) of the Company’s common stock for the ten-day period preceding August 13, 2024 (determined to be $1.03), and the price per share of the Company’s first financing event within six months of the Third Amendment date, or February 13, 2025. As the modification only impacts the exercise price, the amendment does not impact the number of shares the lenders may purchase pursuant to the Warrants. As of September 30, 2024, the Company had issued 2.6 million warrants associated with the Initial Loan (“Initial Warrants”) to purchase common stock and a contractual life of 7 years from the Effective Date. As a result of the Third Amendment, the price adjustment feature on the warrant exercise price is affected by variables that are extraneous to the pricing of a fixed-for-fixed option or forward contract on common shares, and therefore, the Initial Warrants were reclassified from additional paid-in-capital within stockholders' equity to other non-current liabilities on the Condensed Consolidated Balance Sheet (see Note 4, Fair value measurements ). Upon modification of the warrants at the Third Amendment date, the Company recorded the incremental increase in fair value of $0.2 million as debt discount which will be amortized over the life of the Initial Loan at an effective interest rate of 16%. The fair value of the Initial Warrants was then remeasured to $1.0 million at the reporting date of September 30, 2024, resulting in a gain in the amount of $1.1 million recorded within other income, net, on the Condensed Consolidated Statement of Operations. For the three and nine months ended September 30, 2024, the Company recorded approximately $2.8 million and $6.1 million in interest expense associated with the Term Loans, respectively, inclusive of amounts related to the debt discount.

Leases

Leases	9 Months Ended
	Sep. 30, 2024
Leases [Abstract]
Leases	Leases The Company leases certain office and laboratory space, primarily located in Somerville, Massachusetts. Additionally, the Company has embedded leases through its agreements with CMOs and a contract testing organization ("CTO") in both the United States and internationally. Except as described below, there have been no material changes in lease obligations from those disclosed in Note 11 to the consolidated financial statements included in the Company's 2023 Annual Report on Form 10-K. Embedded leases Periodically, throughout the three and nine months ended September 30, 2024, the Company amended several of its embedded contract manufacturing leases, some of which were accounted for as lease modifications under ASC 842. The lease modifications primarily relate to the execution of new statements of work with the vendors or the extension of contractual terms. As it relates to embedded leases related to drug product manufacturing and quality testing, due to lease modification adjustments and amortization, the Company increased its finance lease right-of-use assets in the amount of $10.3 million during the nine months ended September 30, 2024. As it relates to embedded leases related to drug substance manufacturing, due to lease modification adjustments and amortization, the Company decreased its finance lease right-of-use assets in the amount of $12.1 million during the nine months ended September 30, 2024. The following paragraphs describe significant lease modifications to the Company's embedded drug substance manufacturing leases that were executed during the three months ended September 30, 2024. In August 2024, the Company provided its lessor with 12-months’ written notice of its intent to terminate one of its embedded leases effective August 31, 2025. The termination, which relates to an embedded drug vector manufacturing lease, resulted in the reduction to the lease term and the corresponding reduction in fixed lease payments. In September 2024, the Company extended one of its embedded lease for the manufacturing of vector for five years, resulting in a lease term extending through September 2029. The extension resulted in additional fixed lease payments. Summary of all lease costs recognized under ASC 842 The following table contains a summary of the lease costs recognized under ASC 842 and other information pertaining to the Company’s operating and finance leases for the three months and nine months ended September 30, 2024 and 2023 (in thousands): For the three months ended September 30, For the nine months ended September 30, 2024 2023 2024 2023 (As Restated) (As Restated) Finance leases Interest expense $ 2,364 $ 4,311 $ 9,421 $ 12,327 Amortization expense 14,193 6,459 43,896 16,903 Total fixed finance lease cost $ 16,557 $ 10,770 $ 53,317 $ 29,230 Operating leases Fixed lease cost $ 9,486 $ 11,470 $ 28,459 $ 34,411 Total fixed operating lease cost $ 9,486 $ 11,470 $ 28,459 $ 34,411 Variable lease cost 9,129 4,186 22,128 16,140 Short-term lease cost 98 43 265 140 Total lease cost $ 35,270 $ 26,469 $ 104,169 $ 79,921 Operating sublease income $ 10,219 $ 9,742 $ 30,825 $ 30,223 Cash paid in the measurement of lease liabilities Operating cash flows used for operating leases $ 15,323 $ 18,686 Operating cash flows used for finance leases $ 1,411 $ 9,125 Financing cash flows for finance leases $ 69,576 $ 40,299 Supplemental balance sheet information related to leases was as follows: As of As of September 30, 2024 September 30, 2023 Weighted average remaining lease term - finance leases 1.92 years 1.72 years Weighted average discount rate - finance leases 12.56 % 14.49 % Weighted average remaining lease term - operating leases 6.32 years 7.21 years Weighted average discount rate - operating leases 6.97 % 7.02 % As of September 30, 2024, future minimum commitments under ASC 842 under the Company’s leases were as follows (in thousands): Operating Leases Financing Leases Remaining Lease Payments Remainder of 2024 $ 9,151 $ 57,718 2025 37,084 43,068 2026 35,719 2,738 2027 36,742 1,673 2028 37,795 685 2029 and thereafter 81,986 — Total $ 238,477 $ 105,882 Less: Imputed Interest (45,910) (4,036) Present Value of Lease Liabilities $ 192,567 $ 101,846

Commitments and contingencies

Commitments and contingencies	9 Months Ended
	Sep. 30, 2024
Commitments and Contingencies Disclosure [Abstract]
Commitments and contingencies	Commitments and contingencies Lease commitments The Company leases certain office and laboratory space and has embedded leases at CMOs and a CTO. As of September 30, 2024, the Company has commitments arising from forward starting leases that have not yet commenced related to an embedded equipment lease with a CMO. These forward starting leases are expected to commence in the fourth quarter of 2024 and the first quarter of 2025 with an initial term of approximately three Future commitment Remainder of 2024 $ 294 2025 15,047 2026 18,733 2027 18,733 2028 7,668 2029 and thereafter — Total purchase commitments $ 60,475 Litigation From time to time, the Company is party to various claims and complaints arising in the ordinary course of business, including securities class action litigation and intellectual property litigation. The Company enters into standard indemnification agreements in the ordinary course of business. Pursuant to the agreements, the Company indemnifies, holds harmless, and agrees to reimburse the indemnified party for losses suffered or incurred by the indemnified party, generally the Company’s business partners. The term of these indemnification agreements is generally perpetual any time after execution of the agreement. The maximum potential amount of future payments the Company could be required to make under these indemnification agreements is generally unlimited. Accruals for loss contingencies are recognized when a loss is probable, and the amount of such loss can be reasonably estimated. The Company has not accrued for a loss for any matter as a loss is not probable and a loss, or a range of loss, is not reasonably estimable. On April 27, 2023, San Rocco Therapeutics, LLC ("SRT") filed another complaint against the Company (as well as against Mr. Nick Leschly, Mr. Mitchell Finer, Mr. Philip Reilly, Third Rock Ventures LLC, and 2Seventy Bio, Inc.) in the United States District Court for the District of Massachusetts. This complaint alleges civil violations of the Federal Racketeer Influenced and Corrupt Organizations Act, violations of Mass. Gen. Laws ch. 93A, § 11, and fraudulent inducement of SRT into a release provision in a November 2020 confidential settlement agreement we executed with, inter alia, SRT. The allegations relate to the Company's use of the BB305 lentiviral vector, including in connection with the beti-cel program, and SRT seeks declaratory relief and money damages. On July 3, 2023, the Company (in conjunction with the other defendants) moved to dismiss all claims with prejudice brought by SRT in its Complaint for failure to state a claim upon which relief may be granted. On August 7, 2023, SRT filed an amended complaint, adding Craig Thompson as a defendant, and adding additional claims of alleged antitrust violations under federal and state law. The case is now captioned San Rocco Therapeutics, LLC v. Nick Leschly, Mitchell Finer, Philip Reilly, Craig Thompson, Third Rock Ventures LLC, bluebird bio, Inc. and 2Seventy Bio, Inc., C.A. No. 1:23-cv-10919-ADB. On September 18, 2023, the Company (in conjunction with the non-Thompson defendants), moved to dismiss with prejudice once again. SRT filed an opposition to that motion on October 12, 2023. On October 24, 2023, the Company filed a motion for leave to file a reply brief, which was granted on October 30, 2023. SRT filed a sur-reply brief on November 2, 2023. On September 30, 2024, the court issued a Memorandum and Opinion granting the motion to dismiss filed by the non-Thompson defendants as well as a motion to dismiss filed by Mr. Thompson. On October 2, 2024, the court issued an Order dismissing SRT's amended complaint, and closing the case. SRT's time to file any notice of appeal has expired, rendering the court's ruling a final non-appealable decision. On April 15, 2024, SRT filed a Demand for Arbitration with the American Arbitration Association, accusing the Company of breaching a November 2020 confidential settlement agreement by initiating a proceeding before the Patent Trial & Appeal Board (PTAB) of the United States Patent & Trademark Office in October 2022, asserting invalidity of two patents licensed to SRT. SRT seeks reimbursement of its costs and fees, including attorney’s fees, incurred in the PTAB proceeding, totaling approximately $1.5 million. On August 26, 2024, the parties submitted their respective opening dispositive briefs. The Company filed its response on September 24, 2024, when SRT also filed its opposition to our dispositive motion. The parties' respective replies were due on October 8, 2024. On October 29, 2024, the arbitrator granted the Company's early dispositive motion and dismissed SRT's claim in its entirety. On March 28, 2024, a class action lawsuit captioned Garry Gill v. bluebird bio, Inc. et al., Case No. 1:24-cv-10803-PBS (the " Gill Action"), was filed against the Company in the United States District Court for the District of Massachusetts. An amended complaint was filed on August 15, 2024. The amended complaint purports to assert claims against the Company and certain of its current and former officers pursuant to Sections 10(b) and 20(a) of the Securities Exchange Act of 1934, as amended, and Rule 10b-5 promulgated thereunder, on behalf of a putative class of investors who purchased or otherwise acquired the Company’s shares between April 24, 2023 and December 8, 2023 (the “class period”). Plaintiff seeks to recover damages allegedly caused by purported misstatements and omissions regarding (i) whether the Company could obtain FDA approval for the lovo-cel BLA without a black box warning for hematologic malignancies; and (ii) whether the Company would be granted a priority review voucher by the FDA in connection with the BLA, which it could sell in order to strengthen its financial position. The amended complaint claims these alleged statements and omissions operated to artificially inflate the price paid for the Company's common stock during the class period. On September 2, 2024, the Court entered the parties’ stipulated schedule for briefing a motion to dismiss the amended complaint. The Company's opening brief in support of a motion to dismiss was filed on October 11, 2024; the opposition brief is due December 5, 2024; and a reply brief in further support of a motion to dismiss is due December 20, 2024. The Company intends to vigorously defend against the claims in this action. Apart from the above, there have been no other material changes in claims and complaints from those disclosed in Note 12 to the consolidated financial statements included in the Company's 2023 Annual Report on Form 10-K. The Company also indemnifies each of its officers and directors for certain events or occurrences, subject to certain limits, while the officer or director is or was serving at the Company's request in such capacity, as permitted under Delaware law and in accordance with its certificate of incorporation and by-laws. The term of the indemnification period lasts as long as such officer or director may be subject to any proceeding arising out of acts or omissions of such officer or director in such capacity. The maximum amount of potential future indemnification is unlimited; however, the Company currently holds director and officer liability insurance. This insurance allows the transfer of risk associated with the Company's exposure and may enable it to recover a portion of any future amounts paid. The Company believes that the fair value of these indemnification obligations is minimal. Accordingly, it has not recognized any liabilities relating to these obligations.

Equity

Equity	9 Months Ended
	Sep. 30, 2024
Equity [Abstract]
Equity	Equity On January 18, 2023, the Company entered into an underwriting agreement (the “January Underwriting Agreement”) with Goldman and J.P. Morgan Securities LLC in connection with the public offering, issuance, and sale by the Company of 20.0 million shares of the Company’s common stock at a public offering price of $6.00 per share, less underwriting discounts and commissions, pursuant to an effective shelf registration statement on Form S-3 and a related prospectus supplement filed with the Securities and Exchange Commission. Under the terms of the January Underwriting Agreement, the Company also granted the underwriters an option exercisable for 30 days to purchase up to an additional 3.0 million shares of common stock at the public offering price, less underwriting discounts and commissions, which the underwriters exercised in full. The offering closed on January 23, 2023. The Company received aggregate net proceeds of $130.5 million. In August 2023, the Company entered into an Open Market Sales Agreement (the "Sales Agreement") with Jefferies LLC ("Jefferies") to sell shares of the Company’s common stock up to $125.0 million, from time to time, through an “at the market” equity offering program under which Jefferies will act as sales agent. As of September 30, 2024, the Company has made no sales pursuant to the Sales Agreement.

Stock-based compensation

Stock-based compensation	9 Months Ended
	Sep. 30, 2024
Share-Based Payment Arrangement [Abstract]
Stock-based compensation	Stock-based compensation In June 2023, the Company’s stockholders approved the bluebird bio, Inc. 2023 Incentive Award Plan (the “2023 Plan”), which replaced the 2013 Stock Option and Incentive Plan (“2013 Plan”). Following approval of the 2023 Plan, no further awards will be granted under the 2013 Plan. The Company also maintains the 2021 Inducement Plan (the “2021 Plan”), pursuant to which equity-based awards may be granted to new hires. As of September 30, 2024, the total number of shares of common stock available for issuance under the 2023 Plan was approximately 1.5 million, and the total number of shares of common stock available for issuance under the 2021 Plan was approximately 0.6 million. Stock-based compensation expense The Company recognized stock-based compensation expense totaling $2.7 million and $4.9 million during the three months ended September 30, 2024 and 2023, respectively. The Company recognized stock-based compensation expense totaling $9.7 million and $16.0 million during the nine months ended September 30, 2024 and 2023, respectively. Stock-based compensation expense recognized by award type is included within the condensed consolidated statements of operations and comprehensive loss was as follows (in thousands): For the three months ended September 30, For the nine months ended September 30, 2024 2023 2024 2023 Stock options $ 920 $ 1,758 $ 3,343 $ 5,192 Restricted stock units 1,755 2,916 6,217 10,552 Employee stock purchase plan and other 26 194 109 269 $ 2,701 $ 4,868 $ 9,669 $ 16,013 Stock-based compensation expense by classification included within the condensed consolidated statements of operations and comprehensive loss was as follows (in thousands): For the three months ended September 30, For the nine months ended September 30, 2024 2023 2024 2023 Cost of product revenue 102 342 882 435 Selling, general and administrative 1,650 2,461 5,783 7,503 Research and development 681 2,065 2,736 8,075 Restructuring Expenses 268 — 268 — $ 2,701 $ 4,868 $ 9,669 $ 16,013 During the nine months ended September 30, 2024 and 2023, the Company had $1.0 million and $1.4 million of stock compensation expense that was capitalized into inventory. Stock options The following table summarizes the stock option activity under the Company’s equity award plans excluding awards held by employees of 2seventy bio: Shares (in thousands) Weighted- average exercise price per share Outstanding at December 31, 2023 4,227 $ 14.16 Granted 3,010 $ 1.47 Exercised — $ — Canceled, forfeited, or expired (905) $ 10.52 Outstanding at September 30, 2024 6,332 $ 8.66 Exercisable at September 30, 2024 2,290 $ 18.54 Vested and expected to vest at September 30, 2024 6,332 $ 8.66 During the nine months ended September 30, 2024, no stock options were exercised. Restricted stock units The following table summarizes the restricted stock unit activity under the Company’s equity award plans excluding awards held by employees of 2seventy bio: Shares Weighted- Unvested at December 31, 2023 4,207 $ 6.08 Granted 3,357 $ 1.23 Vested (1,083) $ 7.08 Forfeited (907) $ 4.05 Unvested at September 30, 2024 5,574 $ 3.29 Employee stock purchase plan In June 2013, the Company's board of directors adopted its 2013 Employee Stock Purchase Plan (“2013 ESPP”), which authorized the initial issuance of up to a total of 0.2 million shares of the Company’s common stock to participating employees. In June 2021, the Company amended the 2013 ESPP to authorize an additional 1.4 million shares of the Company’s common stock available to participating employees. During each of the nine months ended September 30, 2024 and 2023, 0.1 million shares and 0.1 million shares, respectively, of common stock were issued under the 2013 ESPP.

Income taxes

Income taxes	9 Months Ended
	Sep. 30, 2024
Income Tax Disclosure [Abstract]
Income taxes	Income taxes Deferred tax assets and deferred tax liabilities are recognized based on temporary differences between the financial reporting and tax basis of assets and liabilities using statutory rates. A valuation allowance is recorded against deferred tax assets if it is more likely than not that some or all of the deferred tax assets will not be realized. Due to the uncertainty surrounding the realization of the favorable tax attributes in future tax returns, the Company has recorded a full valuation allowance against the Company’s otherwise recognizable net deferred tax assets. The tax benefit recognized during the three and nine months ended September 30, 2024 was $0.1 million and $0.0 million, respectively, due to the full valuation allowance.

Net loss per share

Net loss per share	9 Months Ended
	Sep. 30, 2024
Earnings Per Share [Abstract]
Net loss per share	Net loss per share The following common stock equivalents were excluded from the calculation of diluted net loss per share for the periods indicated because including them would have had an anti-dilutive effect (in thousands): For the three and nine months ended 2024 2023 Outstanding stock options (1) 7,473 5,875 Restricted stock units (1) 5,574 4,194 Warrants 2,586 — ESPP shares and other 61 — 15,694 10,069 (1) Outstanding stock options and restricted stock units include awards outstanding to employees of 2seventy bio. Net loss per share for the three and nine months ended September 30, 2024 was $0.31 and $1.10, respectively. Net loss per share for the three and nine months ended September 30, 2023 was $0.80 and $1.23, respectively.

Reduction in workforce

Reduction in workforce	9 Months Ended
	Sep. 30, 2024
Restructuring and Related Activities [Abstract]
Reduction in workforce	Reduction in workforce In September 2024, the Company’s board of directors approved a restructuring action (the "Restructuring") following a comprehensive review of the Company’s operations. The Restructuring includes a reduction of the Company’s workforce by 94 employees, or approximately 25% of employees. As a result of the Restructuring, the Company incurred aggregate charges of $2.8 million in restructuring costs, $2.5 million of which relates to cash expenditures for severance and employee termination-related costs to be paid out over multiple weeks through the first quarter of 2025, with the majority to be paid out by December 31, 2024, and $0.3 million in stock-based compensation expense associated with accelerated vesting of restricted stock units. The following table summarizes the accrued liabilities activity recorded in connection with the reduction in workforce for the nine months ended September 30, 2024: For the nine months ended September 30, 2024 Cash expenditure charges $ 2,543 Amount paid through September 30, 2024 — Amounts accrued at September 30, 2024 $ 2,543

Restatement of Previously Issue

Restatement of Previously Issued Financial Statements	9 Months Ended
	Sep. 30, 2024
Accounting Changes and Error Corrections [Abstract]
Restatement of Previously Issued Financial Statements	Restatement of Previously Issued Financial Statements As further described below, as well as in Note 2 - Basis of Presentation, the Company identified several prior period misstatements that impacted its unaudited quarterly condensed consolidated financial statements for the three and nine months ended September 30, 2023. Such restated and unaudited quarterly financial data and the related impacted amounts were presented in the Company's Annual Report on Form 10-K for the year ended December 31, 2023. As part of the restatement, the Company recorded adjustments to correct the material misstatements related to accounting for embedded leases and other immaterial errors. The following tables present the restated unaudited Condensed Consolidated Financial Information for the three and nine months ended September 30, 2023. Consolidated Statements of Operations and Comprehensive Loss For the three months ended September 30, 2023 As Previously Reported Adjustments to Embedded Leases Other Adjustments As Restated Revenue: Product revenue, net $ 12,281 $ — $ — $ 12,281 Other revenue 111 — — 111 Total revenues 12,392 — — 12,392 Cost of product revenue 10,955 (1,829) — 9,126 Gross margin 1,437 1,829 — 3,266 Operating expenses: Selling, general and administrative 40,703 68 — 40,771 Research and development 45,463 14,757 (1,719) 58,501 Total operating expenses 86,166 14,825 (1,719) 99,272 Loss from operations (84,729) (12,996) 1,719 (96,006) Interest income 2,454 — — 2,454 Interest expense — (4,311) — (4,311) Other income, net 10,544 168 (81) 10,631 Loss before income taxes (71,731) (17,139) 1,638 (87,232) Income tax (expense) benefit — — — — Net loss (71,731) (17,139) 1,638 (87,232) Net loss per share - basic (1) $ (0.66) $ (0.16) $ 0.02 $ (0.80) Net loss per share - diluted (1) $ (0.66) $ (0.16) $ 0.02 $ (0.80) Weighted-average number of common shares used in computing net loss per share - basic: 109,098 — — 109,098 Weighted-average number of common shares used in computing net loss per share - diluted: 109,098 — — 109,098 Other comprehensive income (loss): Other comprehensive income (loss), net of tax (benefit) expense of $0.0 million for the three months ended September 30, 2023 137 — — 137 Total other comprehensive income (loss) 137 — — 137 Comprehensive loss $ (71,594) $ (17,139) $ 1,638 $ (87,095) (1) Due to differences in rounding to the nearest cent per basic or diluted share, totals may not equal the sum of the line items. For the nine months ended September 30, 2023 As Previously Reported Adjustments to Embedded Leases Other Adjustments As Restated Revenue: Product revenue, net $ 21,414 $ — $ — $ 21,414 Other revenue 249 — — 249 Total revenues 21,663 — — 21,663 Cost of product revenue 23,895 (2,560) — 21,335 Gross margin (2,232) 2,560 — 328 Operating expenses: Selling, general and administrative 118,406 294 — 118,700 Research and development 133,881 52 (2,397) 131,536 Total operating expenses 252,287 346 (2,397) 250,236 Gain from sale of priority review voucher, net 92,930 — — 92,930 Loss from operations (161,589) 2,214 2,397 (156,978) Interest income 7,961 — — 7,961 Interest expense (3) (12,328) — (12,331) Other income, net 30,152 106 (81) 30,177 Loss before income taxes (123,479) (10,008) 2,316 (131,171) Income tax (expense) benefit 80 — — 80 Net loss (123,399) (10,008) 2,316 (131,091) Net loss per share - basic $ (1.15) $ (0.09) $ 0.02 $ (1.23) Net loss per share - diluted $ (1.15) $ (0.09) $ 0.02 $ (1.23) Weighted-average number of common shares used in computing net loss per share - basic: 106,924 — — 106,924 Weighted-average number of common shares used in computing net loss per share - diluted: 106,924 — — 106,924 Other comprehensive income (loss): Other comprehensive income (loss), net of tax (benefit) expense of $0.0 million for the nine months ended September 30, 2023 1,843 — — 1,843 Total other comprehensive income (loss) 1,843 — — 1,843 Comprehensive loss $ (121,556) $ (10,008) $ 2,316 $ (129,248) (1) Due to differences in rounding to the nearest cent per basic or diluted share, totals may not equal the sum of the line items. Statements of Changes in Stockholders' Equity: Common stock Additional Accumulated other comprehensive income (loss) Accumulated Total Shares Amount As Previously Reported Balances at December 31, 2022 82,923 $ 830 $ 4,186,086 $ (4,070) $ (3,986,503) $ 196,343 Vesting of restricted stock 382 3 (198) — — (195) Exercise of stock options 3 — 7 — — 7 Purchase of shares under ESPP 62 1 226 — — 227 Issuance of common stock for private equity placement 23,000 230 130,061 — — 130,291 Stock-based compensation — — 5,843 — — 5,843 Other comprehensive income (loss) — — — 984 — 984 Net income (loss) — — — — 21,240 21,240 Balances at March 31, 2023 106,370 $ 1,064 $ 4,322,025 $ (3,086) $ (3,965,263) $ 354,740 Adjustments to Embedded Leases Balances at December 31, 2022 $ — $ — $ — $ — $ (59,700) $ (59,700) Vesting of restricted stock — — — — — — Exercise of stock options — — — — — — Purchase of shares under ESPP — — — — — — Issuance of common stock for private equity placement — — — — — — Stock-based compensation — — — — — — Other comprehensive income (loss) — — — — — — Net income (loss) — — — — (2,351) (2,351) Balances at March 31, 2023 — $ — $ — $ — $ (62,051) $ (62,051) Other Adjustments Balances at December 31, 2022 — — (98) — (2,212) (2,310) Vesting of restricted stock — — — — — — Exercise of stock options — — — — — — Purchase of shares under ESPP — — — — — — Issuance of common stock for private equity placement — — — — — — Stock-based compensation — — — — — — Other comprehensive income (loss) — — — — — — Net income (loss) — — — — 41 41 Balances at March 31, 2023 — $ — $ (98) $ — $ (2,171) $ (2,269) As Restated Balances at December 31, 2022 82,923 830 4,185,988 (4,070) (4,048,415) 134,333 Vesting of restricted stock 382 3 (198) — — (195) Exercise of stock options 3 — 7 — — 7 Purchase of shares under ESPP 62 1 226 — — 227 Issuance of common stock for private equity placement 23,000 230 130,061 — — 130,291 Stock-based compensation — — 5,843 — — 5,843 Other comprehensive income (loss) — — — 984 — 984 Net income (loss) — — — — 18,930 18,930 Balances at March 31, 2023 106,370 $ 1,064 $ 4,321,927 $ (3,086) $ (4,029,485) $ 290,420 Common stock Additional Accumulated Accumulated Total Shares Amount As Previously Reported Balances at March 31, 2023 106,370 $ 1,064 $ 4,322,025 $ (3,086) $ (3,965,263) $ 354,740 Vesting of restricted stock 65 1 (1) — — — Exercise of stock options 19 — 77 — — 77 Purchase of shares under ESPP — — — — — — Issuance of common stock for private equity placement — — — — — — Stock-based compensation — — 6,388 — — 6,388 Other comprehensive income (loss) — — — 722 — 722 Net income (loss) — — — — (72,908) (72,908) Balances at June 30, 2023 106,454 $ 1,065 $ 4,328,489 $ (2,364) $ (4,038,171) $ 289,019 Adjustments to Embedded Leases Balances at March 31, 2023 $ — $ — $ — $ — $ (62,051) $ (62,051) Vesting of restricted stock — — — — — — Exercise of stock options — — — — — — Purchase of shares under ESPP — — — — — — Issuance of common stock for private equity placement — — — — — — Stock-based compensation — — — — — — Other comprehensive income (loss) — — — — — — Net income (loss) — — — — 9,482 9,482 Balances at June 30, 2023 — $ — $ — $ — $ (52,569) $ (52,569) Other Adjustments Balances at March 31, 2023 — — (98) — (2,171) (2,269) Vesting of restricted stock — — — — — — Exercise of stock options — — — — — — Purchase of shares under ESPP — — — — — — Issuance of common stock for private equity placement — — — — — — Stock-based compensation — — — — — — Other comprehensive income (loss) — — — — — — Net income (loss) — — — — 637 637 Balances at June 30, 2023 — $ — $ (98) $ — $ (1,534) $ (1,632) As Restated Balances at March 31, 2023 106,370 1,064 4,321,927 (3,086) (4,029,485) 290,420 Vesting of restricted stock 65 1 (1) — — — Exercise of stock options 19 — 77 — — 77 Purchase of shares under ESPP — — — — — — Issuance of common stock for private equity placement — — — — — — Stock-based compensation — — 6,388 — — 6,388 Other comprehensive income (loss) — — — 722 — 722 Net income (loss) — — — — (62,789) (62,789) Balances at June 30, 2023 106,454 $ 1,065 $ 4,328,391 $ (2,364) $ (4,092,274) $ 234,818 Common stock Additional Accumulated Accumulated Total Shares Amount As previously reported Balances at June 30, 2023 106,454 $ 1,065 $ 4,328,489 $ (2,364) $ (4,038,171) $ 289,019 Vesting of restricted stock 566 6 (6) — — — Exercise of stock options 2 — 8 — — 8 Issuance of common stock — — (50) — — (50) Stock-based compensation expense — — 5,153 — — 5,153 Other comprehensive income (loss) — — — 137 — 137 Net income (loss) — — — — (71,731) (71,731) Balances at September 30, 2023 107,022 107,022 $ 1,071 $ 4,333,594 $ (2,227) $ (4,109,902) $ 222,536 Balances at Adjustments to Leases Balances at June 30, 2023 — — — — (52,569) (52,569) Vesting of restricted stock — — — — — — Exercise of stock options — — — — — — Issuance of common stock — — — — — — Stock-based compensation expense — — — — — — Other comprehensive income (loss) — — — — — — Net income (loss) — — — — (17,139) (17,139) Balances at September 30, 2023 — $ — $ — $ — $ (69,708) $ (69,708) Balances at Other Adjustments Balances at June 30, 2023 — — (98) — (1,534) (1,632) Vesting of restricted stock — — — — — — Exercise of stock options — — — — — — Issuance of common stock — — — — — — Stock-based compensation expense — — — — — — Other comprehensive income (loss) — — — — — — Net income (loss) — — — — 1,638 1,638 Balances at September 30, 2023 — $ — $ (98) $ — $ 104 $ 6 Balances at As Restated Balances at June 30, 2023 106,454 1,065 4,328,391 (2,364) (4,092,274) 234,818 Vesting of restricted stock 566 6 (6) — — — Exercise of stock options 2 — 8 — — 8 Issuance of common stock — — (50) — — (50) Stock-based compensation expense — — 5,153 — — 5,153 Other comprehensive income (loss) — — — 137 — 137 Net income (loss) — — — — (87,232) (87,232) Balances at September 30, 2023 107,022 $ 1,071 $ 4,333,496 $ (2,227) $ (4,179,506) $ 152,834 Consolidated Statement of Cash Flows For the nine months ended September 30, 2023 As Previously Reported Adjustments to Leases Other Adjustments As Restated Cash flows from operating activities: Net loss $ (123,399) $ (10,008) $ 2,316 $ (131,091) Adjustments to reconcile net loss to net cash used in operating activities: Depreciation and amortization 3,124 16,648 (112) 19,660 Stock-based compensation expense 16,013 — — 16,013 Noncash research and development expense (finance lease) — 22,223 — 22,223 Noncash operating lease expense — 23,965 — 23,965 Gain from sale of priority review voucher (92,930) — — (92,930) Excess inventory reserve 5,333 1,554 2,315 9,202 Other non-cash items 19 — 81 100 (Gain) loss on foreign currency exchange rates — (1,062) — (1,062) Changes in operating assets and liabilities: Accounts receivable (23,000) — 8,400 (14,600) Prepaid expenses and other assets (523) 2,640 — 2,117 Inventory (24,931) 1,651 (2,917) (26,197) Operating right of use assets 40,101 (40,101) — — Accounts payable (5,787) 7,183 316 1,712 Accrued expenses and other liabilities 7,125 583 (1,999) 5,709 Accrued interest payable under finance lease — 3,203 — 3,203 Operating lease liabilities (30,506) 11,820 — (18,686) Deferred revenue 8,152 — (8,400) (248) Net cash (used in) provided by operating activities (221,209) 40,299 — (180,910) Cash flows from investing activities: Purchase of property, plant and equipment (2,975) — — (2,975) Purchases of marketable securities (43,297) — — (43,297) Proceeds from maturities of marketable securities 99,521 — — 99,521 Proceeds from sales of marketable securities 5,853 — — 5,853 Purchase of intangible assets (868) — — (868) Proceeds from sale of priority review voucher 92,930 — — 92,930 Net cash provided by investing activities 151,164 — — 151,164 Cash flows from financing activities: Proceeds from exercise of stock options and ESPP contributions 93 — — 93 Proceeds from vesting of restricted stock (196) — — (196) Principal payments on finance lease — (40,299) — (40,299) Proceeds from the secondary public offering, net of issuance costs 130,072 — — 130,072 Net cash (used in) provided by financing activities 129,969 (40,299) — 89,670 Increase in cash, cash equivalents and restricted cash 59,924 — — 59,924 Cash, cash equivalents and restricted cash at beginning of year 158,445 — — 158,445 Cash, cash equivalents and restricted cash at end of year $ 218,369 $ — $ — $ 218,369 Reconciliation of cash, cash equivalents and restricted cash: Cash and cash equivalents $ 165,347 $ — $ — $ 165,347 Restricted cash included in receivables and other current assets 8,885 — — 8,885 Restricted cash included in restricted cash and other non-current assets 44,137 — — 44,137 Total cash, cash equivalents and restricted cash $ 218,369 $ — $ — $ 218,369 Supplemental cash flow disclosures: Right-of-use assets obtained in exchange for operating lease liabilities 44,819 (45,527) — (708) Purchases of property, plant and equipment included in accounts 941 — — 941 Offering expenses included in accounts payable and accrued expenses 248 — — 248 Right-of-use assets obtained in exchange for finance lease liabilities — 21,508 — 21,508 Increase (reduction) of right of use asset and associated operating lease liability due to lease reassessment 8,003 (8,003) — — Cash paid during the period for income taxes 5 — — 5

Subsequent events

Subsequent events	9 Months Ended
	Sep. 30, 2024
Subsequent Events [Abstract]
Subsequent events	Subsequent events On November 6, 2024, the Company’s stockholders approved a proposal to amend and restate the Company’s 2023 Plan to (i) increase the aggregate number of shares authorized for issuance under the 2023 Plan by 15,000,000 shares to 20,200,000 shares, (ii) include minimum vesting requirements for certain awards granted thereunder, (iii) clarify the treatment of performance-based awards in the event of a change in control and (iv) extend the date following which incentive stock options can no longer be granted to September 12, 2034, the tenth anniversary of the date the Company’s board of directors approved the amended and restated plan (such amended and restated plan, the “Amended 2023 Plan”).

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 loss	$ (60,808)	$ (81,393)	$ (69,804)	$ (87,232)	$ (62,789)	$ 18,930	$ (212,003)	$ (131,091)

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

Basis of presentation, princi_2

Basis of presentation, principles of consolidation and significant accounting policies (Policies)	9 Months Ended
	Sep. 30, 2024
Accounting Policies [Abstract]
Basis of presentation	Basis of presentation The accompanying condensed consolidated financial statements are unaudited and have been prepared by the Company in accordance with accounting principles generally accepted in the United States (“GAAP”). Any reference in these notes to applicable guidance is meant to refer to the authoritative United States GAAP as included in the Accounting Standard Codification (“ASC”) and Accounting Standards Updates (“ASUs”) of the Financial Accounting Standards Board (“FASB”). Certain information and footnote disclosures normally included in the Company’s annual financial statements have been condensed or omitted. These condensed consolidated financial statements, in the opinion of management, reflect all normal recurring adjustments necessary for a fair presentation of the Company’s financial position and results of operations for the interim periods ended September 30, 2024 and 2023.
Consolidation	The accompanying condensed consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries. All intercompany balances and transactions have been eliminated in consolidation. The Company views its operations and manages its business in one operating segment.
Reclassification of Prior Year Presentation	Reclassification of Prior Year Presentation Certain prior year amounts have been reclassified to conform to the current year presentation. Specifically, interest expense has been reclassified from interest income to interest expense in the consolidated statement of operations and comprehensive loss. These reclassifications had no effect on the reported results of operations.
Use of estimates	Use of estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts in the financial statements and accompanying notes. Actual results could materially differ from those estimates. Management considers many factors in selecting appropriate financial accounting policies and controls, and in developing the estimates and assumptions that are used in the preparation of these financial statements. Management must apply significant judgment in this process. In addition, other factors may affect estimates, including: expected business and operational changes, sensitivity and volatility associated with the assumptions used in developing estimates, and whether historical trends are expected to be representative of future trends. The estimation process often may yield a range of potentially reasonable estimates of the ultimate future outcomes and management must select an amount that falls within that range of reasonable estimates. This process may result in actual results differing materially from those estimated amounts used in the preparation of the financial statements. Estimates and judgments are used in the following areas, among others: the alternative future use of assets used in research and development activities, realizability of inventories, future undiscounted cash flows and subsequent fair value estimates used to assess potential and measure any impairment of long-lived assets, including goodwill and intangible assets, and the measurement of right-of-use assets and lease liabilities, gross-to-net revenue calculations, stock-based compensation expense, accrued expenses, income taxes, the assessment of the Company's ability to fund its operations for at least the next twelve months from the date of issuance of these financial statements, and the assessment of the likelihood and magnitude of losses that may be sustained upon resolution of contingencies.
Inventory	Inventory Inventories are stated at the lower of cost or net realizable value under the first-expired, first-out ("FEFO") methodology. Given human gene therapy products are a new and novel category of therapeutics and future economic benefit is not probable until regulatory approval for the product has been obtained, the Company has only considered inventory for capitalization upon regulatory approval. Manufacturing costs incurred prior to regulatory approval for pre-launch inventory that did not qualify for capitalization and clinical manufacturing costs are charged to research and development expense in the Company’s consolidated statements of operations and comprehensive loss as costs are incurred. Additionally, inventory that initially qualifies for capitalization but that may ultimately be used to produce clinical drug product is expensed as research and development expense when it has been designated for the manufacture of clinical drug product. Inventory consists of cell banks, plasmids, LVV, other materials and compounds sourced from third party suppliers and utilized in the manufacturing process, and drug product which has been produced for the treatment of specific patients, that are owned by the Company until infusion. Management periodically reviews inventories for excess or obsolescence, considering factors such as sales forecasts compared to quantities on-hand and firm purchase commitments as well as remaining shelf life of on-hand inventories. The Company writes down its inventory that is in excess, obsolete or otherwise unmarketable to its estimated net realizable value in the period in which the impairment is first identified. Any such adjustments are included as a component of cost of goods sold within cost of product revenue in the Company’s consolidated statements of operations and comprehensive loss.
Revenue recognition	Revenue recognition Under ASC Topic 606, Revenue from Contracts with Customers (“Topic 606”), an entity recognizes revenue when its customer obtains control of promised goods or services, in an amount that reflects the consideration that the entity expects to receive in exchange for those goods or services. To determine revenue recognition for arrangements that an entity determines are within the scope of Topic 606, the entity performs the following five steps: (i) identify the contract(s) with a customer; (ii) identify the performance obligations in the contract; (iii) determine the transaction price, including variable consideration, if any; (iv) allocate the transaction price to the performance obligations in the contract; and (v) recognize revenue when (or as) the entity satisfies a performance obligation. The Company only applies the five-step model to contracts when it is probable that the entity will collect the consideration to which it is entitled in exchange for the goods or services it transfers to the customer. Once a contract is determined to be within the scope of Topic 606, the Company assesses the goods or services promised within each contract and determines those that are performance obligations. Arrangements that include rights to additional goods or services that are exercisable at a customer’s discretion are generally considered options. The Company assesses if these options provide a material right to the customer and if so, they are considered performance obligations. The Company assesses whether each promised good or service is distinct to identify the performance obligations in the contract. This assessment involves subjective determinations and requires management to make judgments about the individual promised goods or services and whether such are separable from the other aspects of the contractual relationship. Promised goods and services are considered distinct provided that: (i) the customer can benefit from the good or service either on its own or together with other resources that are readily available to the customer (that is, the good or service is capable of being distinct) and (ii) the entity’s promise to transfer the good or service to the customer is separately identifiable from other promises in the contract (that is, the promise to transfer the good or service is distinct within the context of the contract). The transaction price is then determined and allocated to the identified performance obligations in proportion to their standalone selling prices (“SSP”) on a relative SSP basis. SSP is determined at contract inception and is not updated to reflect changes between contract inception and when the performance obligations are satisfied. If the consideration promised in a contract includes a variable amount, the Company estimates the amount of consideration to which it will be entitled in exchange for transferring the promised goods or services to a customer. The Company determines the amount of variable consideration by using the expected value method or the most likely amount method. The Company includes the unconstrained amount of estimated variable consideration in the transaction price. The amount included in the transaction price is constrained to the amount for which it is probable that a significant reversal of cumulative revenue recognized will not occur. At the end of each subsequent reporting period, the Company re-evaluates the estimated variable consideration included in the transaction price and any related constraint, and if necessary, adjusts its estimate of the overall transaction price. Any such adjustments are recorded on a cumulative catch-up basis in the adjustment period. In determining the transaction price, the Company adjusts consideration for the effects of the time value of money if the timing of payments provides the Company with a significant benefit of financing. The Company does not assess whether a contract has a significant financing component if the expectation at contract inception is such that the period between payment by the licensees and the transfer of the promised goods or services to the licensees will be one year or less. The Company assessed each of its revenue generating arrangements to determine whether a significant financing component exists and concluded that a significant financing component does not exist in any of its arrangements. The Company then recognizes as revenue the amount of the transaction price that is allocated to the respective performance obligation when (or as) each performance obligation is satisfied, either at a point in time or over time, and if over time recognition is based on the use of an output or input method. Product revenue In 2022, the Company received approval of ZYNTEGLO and SKYSONA from the FDA. In 2023, the Company received approval of LYFGENIA from the FDA. The amount of revenue recognized by the Company is equal to the amount of consideration that is expected to be received from the sale of product to its customers. The Company uses Specialty Distributors ("SD") and Specialty Pharmacies ("SP") to deliver product to the Qualified Treatment Centers ("QTC"). Revenue is only recognized when the performance obligation is satisfied. The Company recognizes revenue upon infusion to the patient. To determine whether a significant reversal will occur in future periods, the Company will assess both the likelihood and magnitude of any such potential reversal of revenue. Gross product revenue is reduced by outcomes-based rebates, other rebates and distributor fees. Rebates expense Rebates are based on contractual arrangements or statutory requirements and include amounts due to Medicaid agencies and third-party payers. These amounts may vary by product and payer. Rebates are estimated primarily based on product sales, including product mix and pricing, historical and estimated payer mix and discount rates, among other inputs, which require significant estimates and judgment. The Company assesses and updates estimates each reporting period to reflect actual claims and other current information. Rebates that are payable to Medicaid agencies and third-party payers are recorded in accrued expenses and other current liabilities on the Company's consolidated balance sheets. Distributor fees The Company pays distribution fees to SDs and SPs in connection with the sales of our product. These distributor fees are based on a contractually determined fixed percentage of sales. Other revenue In 2021, the Company entered into a grant agreement with the Bill and Melinda Gates Foundation. The Company recognizes grant revenue in accordance with ASC 958-605, Revenue Recognition Not-for-Profit Entities , when qualifying costs are incurred and barriers to restriction have been overcome. When grant funds are received after costs have been incurred, the Company records revenue and a corresponding grant receivable. Cash received from grants in advance of incurring qualifying costs is recorded as deferred revenue and recognized as revenue when qualifying costs are incurred. In 2023, the Company ceased further research work.
Recent accounting pronouncements	Recent accounting pronouncements In November 2023, the FASB issued ASU 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures to update reportable segment disclosure requirements, primarily through enhanced disclosures about significant segment expenses and information used to assess segment performance and requires companies to disclose all annual disclosures about segments in interim periods. The ASU also requires companies with a single reportable segment to provide all disclosures required by Topic 280 – Segment Reporting. This update is effective beginning with the Company’s 2024 fiscal year annual reporting period and interim periods beginning thereafter. The Company is currently evaluating the impact that the adoption of this standard will have on its consolidated financial statements and disclosures. In December 2023, the FASB issued ASU 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures . This ASU expands disclosures in an entity’s income tax rate reconciliation table and disclosures regarding taxes paid both in the U.S. and foreign jurisdictions. This update is effective beginning with the Company’s 2025 fiscal year annual reporting period. The Company is currently evaluating the impact to its income tax disclosures. In March 2024, the FASB issued ASU 2024-01, Compensation-Stock Compensation (Topic 718): Scope Application of Profits Interest and Similar Awards . This update clarifies the scope of "Profit Interest" and similar awards and adds an illustrative example to the existing ASC 718 standard that includes four fact patterns to demonstrate how an entity should apply the scope guidance in paragraph 718-10-15-3 to determine whether a profits interest award should be accounted for in accordance with Topic 718. The amendments in this ASU are effective for annual periods beginning after December 15, 2024, and interim periods within those annual periods. Early adoption is permitted for interim and annual financial statements not yet issued or made available for issuance. The amendments in this ASU should be applied either (1) retrospectively to all prior periods presented in the financial statements or (2) prospectively to profits interest and similar awards granted or modified on or after the date at which the entity first applies the amendments. The Company is currently evaluating the impact that the adoption of this standard will have on its consolidated financial statements and disclosures. In March 2024, the FASB issued ASU 2024-02 " Codification Improvements—Amendments to Remove References to the Concepts Statements" , which removes various references to concepts statements from the FASB Accounting Standards Codification. This ASU is effective for the Company beginning in the first quarter of fiscal year 2026, with early adoption permitted. The Company expects the new guidance will have an immaterial impact on its consolidated financial statements and intends to adopt the guidance when it becomes effective in the first quarter of fiscal year 2026. In November 2024, the FASB issued ASU 2024-03 "Income Statement—Reporting Comprehensive Income—Expense Disaggregation Disclosures (Subtopic 220-40): Disaggregation of Income Statement Expenses". This ASU requires expanded disclosures of specific income statement expense categories such as cost of product revenue, selling, general, and administrative expenses, and research and development expenses. This update is effective for annual periods beginning after December 15, 2026, and interim periods within fiscal years beginning after December 15, 2027. Early adoption is permitted.

Product revenue and reserves (T

Product revenue and reserves (Tables)	9 Months Ended
	Sep. 30, 2024
Revenue from Contract with Customer [Abstract]
Disaggregation of Revenue	Product revenue by therapy represents: For the three months ended For the nine months ended 2024 2023 2024 2023 ZYNTEGLO $ 5,493 $ 4,851 $ 35,212 $ 9,031 LYFGENIA 2,632 — 2,632 — SKYSONA 2,487 7,430 7,430 12,383 Total product revenue, net $ 10,612 $ 12,281 $ 45,274 $ 21,414
Summary of Contract with Customer, Refund Liability	The following table summarizes an analysis of the change in reserves for gross to net deductions for the periods indicated: Total Balance at December 31, 2023 $ 5,365 Provision for rebates 8,506 Payments/credits — Balance at September 30, 2024 $ 13,871

Fair value measurements (Tables

Fair value measurements (Tables)	9 Months Ended
	Sep. 30, 2024
Fair Value Disclosures [Abstract]
Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis	The following table sets forth the Company’s assets and liabilities that are measured at fair value on a recurring basis as of September 30, 2024 and December 31, 2023 (in thousands): Description Total Quoted prices in active markets (Level 1) Significant other observable inputs (Level 2) Significant unobservable inputs (Level 3) September 30, 2024 Assets: Cash and cash equivalents $ 70,651 $ 70,651 $ — $ — Due from factor: Beneficiary interest in factored invoices 1,062 — — 1,062 Other non-current liabilities Warrant liability 987 — — 987 Total $ 72,700 $ 70,651 $ — $ 2,049 December 31, 2023 Assets: Cash and cash equivalents $ 221,755 $ 221,755 $ — $ — Due from factor: Beneficiary interest in factored invoices 560 — — 560 Total $ 222,315 $ 221,755 $ — $ 560
Schedule of Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation	The following table shows a reconciliation of the beginning and ending balances for due from factor Level 3 financial liabilities measured at fair value on a recurring basis for the nine months ended September 30, 2024: For the nine months ended September 30, 2024 Balance at December 31, 2023 $ 560 Beneficiary interest obtained in transferred invoices 4,850 Gross proceeds from previously transferred invoices (4,240) Accrual for factor reserve deficiency (26) Accrual for anticipated loss on sale of invoices (82) Balance at September 30, 2024 $ 1,062
Schedule of Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation	The following table shows a reconciliation of the beginning and ending balances for other non-current liabilities due from factor Level 3 financial liabilities measured at fair value on a recurring basis for the nine months ended September 30, 2024: For the nine months ended September 30, 2024 Balance at December 31, 2023 $ — Warrant modification and reclassification to liabilities 2,100 Change in fair value (1,113) Balance at September 30, 2024 $ 987

Inventory (Tables)

Inventory (Tables)	9 Months Ended
	Sep. 30, 2024
Inventory Disclosure [Abstract]
Schedule of Inventory, Current	Inventory, net, consists of the following (in thousands): As of September 30, 2024 As of December 31, 2023 Raw materials $ 2,965 $ 2,329 Work in progress 48,649 17,375 Finished goods 2,330 3,215 Inventory $ 53,944 $ 22,919

Accrued expenses and other cu_2

Accrued expenses and other current liabilities (Tables)	9 Months Ended
	Sep. 30, 2024
Payables and Accruals [Abstract]
Summary of Accrued Expenses and Other Current Liabilities	Accrued expenses and other current liabilities consist of the following (in thousands): As of September 30, 2024 As of December 31, 2023 Accrued CMO and CRO costs $ 21,735 $ 24,824 Accrued employee compensation 15,375 19,972 Accrued rebates 13,998 5,365 Accrued goods and services 1,814 8,391 Accrued professional fees 10,070 2,531 Other sublease rent liability 3,379 3,310 Accrued refund liability — 5,600 Other 3,808 3,195 Total accrued expenses and other current liabilities $ 70,179 $ 73,188

Leases (Tables)

Leases (Tables)	9 Months Ended
	Sep. 30, 2024
Leases [Abstract]
Summary of Lease Cost	The following table contains a summary of the lease costs recognized under ASC 842 and other information pertaining to the Company’s operating and finance leases for the three months and nine months ended September 30, 2024 and 2023 (in thousands): For the three months ended September 30, For the nine months ended September 30, 2024 2023 2024 2023 (As Restated) (As Restated) Finance leases Interest expense $ 2,364 $ 4,311 $ 9,421 $ 12,327 Amortization expense 14,193 6,459 43,896 16,903 Total fixed finance lease cost $ 16,557 $ 10,770 $ 53,317 $ 29,230 Operating leases Fixed lease cost $ 9,486 $ 11,470 $ 28,459 $ 34,411 Total fixed operating lease cost $ 9,486 $ 11,470 $ 28,459 $ 34,411 Variable lease cost 9,129 4,186 22,128 16,140 Short-term lease cost 98 43 265 140 Total lease cost $ 35,270 $ 26,469 $ 104,169 $ 79,921 Operating sublease income $ 10,219 $ 9,742 $ 30,825 $ 30,223 Cash paid in the measurement of lease liabilities Operating cash flows used for operating leases $ 15,323 $ 18,686 Operating cash flows used for finance leases $ 1,411 $ 9,125 Financing cash flows for finance leases $ 69,576 $ 40,299 Supplemental balance sheet information related to leases was as follows: As of As of September 30, 2024 September 30, 2023 Weighted average remaining lease term - finance leases 1.92 years 1.72 years Weighted average discount rate - finance leases 12.56 % 14.49 % Weighted average remaining lease term - operating leases 6.32 years 7.21 years Weighted average discount rate - operating leases 6.97 % 7.02 %
Schedule of Future Minimum Commitments Under Operating Leases	As of September 30, 2024, future minimum commitments under ASC 842 under the Company’s leases were as follows (in thousands): Operating Leases Financing Leases Remaining Lease Payments Remainder of 2024 $ 9,151 $ 57,718 2025 37,084 43,068 2026 35,719 2,738 2027 36,742 1,673 2028 37,795 685 2029 and thereafter 81,986 — Total $ 238,477 $ 105,882 Less: Imputed Interest (45,910) (4,036) Present Value of Lease Liabilities $ 192,567 $ 101,846
Schedule of Future Minimum Commitments Under Financing Leases	As of September 30, 2024, future minimum commitments under ASC 842 under the Company’s leases were as follows (in thousands): Operating Leases Financing Leases Remaining Lease Payments Remainder of 2024 $ 9,151 $ 57,718 2025 37,084 43,068 2026 35,719 2,738 2027 36,742 1,673 2028 37,795 685 2029 and thereafter 81,986 — Total $ 238,477 $ 105,882 Less: Imputed Interest (45,910) (4,036) Present Value of Lease Liabilities $ 192,567 $ 101,846

Commitment and contingencies (T

Commitment and contingencies (Tables)	9 Months Ended
	Sep. 30, 2024
Commitments and Contingencies Disclosure [Abstract]
Schedule of Non-cancelable Contractual Obligations	The following table presents the non-cancelable contractual obligations arising from this arrangement as of September 30, 2024 (in thousands): Future commitment Remainder of 2024 $ 294 2025 15,047 2026 18,733 2027 18,733 2028 7,668 2029 and thereafter — Total purchase commitments $ 60,475

Stock-based compensation (Table

Stock-based compensation (Tables)	9 Months Ended
	Sep. 30, 2024
Share-Based Payment Arrangement [Abstract]
Summary of Stock-Based Compensation Expense by Award Type	Stock-based compensation expense recognized by award type is included within the condensed consolidated statements of operations and comprehensive loss was as follows (in thousands): For the three months ended September 30, For the nine months ended September 30, 2024 2023 2024 2023 Stock options $ 920 $ 1,758 $ 3,343 $ 5,192 Restricted stock units 1,755 2,916 6,217 10,552 Employee stock purchase plan and other 26 194 109 269 $ 2,701 $ 4,868 $ 9,669 $ 16,013
Schedule of Stock-Based Compensation Expense by Classification	Stock-based compensation expense by classification included within the condensed consolidated statements of operations and comprehensive loss was as follows (in thousands): For the three months ended September 30, For the nine months ended September 30, 2024 2023 2024 2023 Cost of product revenue 102 342 882 435 Selling, general and administrative 1,650 2,461 5,783 7,503 Research and development 681 2,065 2,736 8,075 Restructuring Expenses 268 — 268 — $ 2,701 $ 4,868 $ 9,669 $ 16,013
Summary of Stock Option Activity Under Plan	The following table summarizes the stock option activity under the Company’s equity award plans excluding awards held by employees of 2seventy bio: Shares (in thousands) Weighted- average exercise price per share Outstanding at December 31, 2023 4,227 $ 14.16 Granted 3,010 $ 1.47 Exercised — $ — Canceled, forfeited, or expired (905) $ 10.52 Outstanding at September 30, 2024 6,332 $ 8.66 Exercisable at September 30, 2024 2,290 $ 18.54 Vested and expected to vest at September 30, 2024 6,332 $ 8.66
Summary of Restricted Common Stock Awards	The following table summarizes the restricted stock unit activity under the Company’s equity award plans excluding awards held by employees of 2seventy bio: Shares Weighted- Unvested at December 31, 2023 4,207 $ 6.08 Granted 3,357 $ 1.23 Vested (1,083) $ 7.08 Forfeited (907) $ 4.05 Unvested at September 30, 2024 5,574 $ 3.29

Net loss per share (Tables)

Net loss per share (Tables)	9 Months Ended
	Sep. 30, 2024
Earnings Per Share [Abstract]
Common Stock Equivalents Excluded from Calculation of Diluted Net Loss Per Share	The following common stock equivalents were excluded from the calculation of diluted net loss per share for the periods indicated because including them would have had an anti-dilutive effect (in thousands): For the three and nine months ended 2024 2023 Outstanding stock options (1) 7,473 5,875 Restricted stock units (1) 5,574 4,194 Warrants 2,586 — ESPP shares and other 61 — 15,694 10,069 (1) Outstanding stock options and restricted stock units include awards outstanding to employees of 2seventy bio.

Reduction in workforce (Tables)

Reduction in workforce (Tables)	9 Months Ended
	Sep. 30, 2024
Restructuring and Related Activities [Abstract]
Summary of Accrued Liability Activity Recorded in Connection with Reduction in Workforce	The following table summarizes the accrued liabilities activity recorded in connection with the reduction in workforce for the nine months ended September 30, 2024: For the nine months ended September 30, 2024 Cash expenditure charges $ 2,543 Amount paid through September 30, 2024 — Amounts accrued at September 30, 2024 $ 2,543

Restatement of Previously Iss_2

Restatement of Previously Issued Financial Statements (Tables)	9 Months Ended
	Sep. 30, 2024
Accounting Changes and Error Corrections [Abstract]
Schedule of Corrections to Impacted Financial Statements	The following tables present the restated unaudited Condensed Consolidated Financial Information for the three and nine months ended September 30, 2023. Consolidated Statements of Operations and Comprehensive Loss For the three months ended September 30, 2023 As Previously Reported Adjustments to Embedded Leases Other Adjustments As Restated Revenue: Product revenue, net $ 12,281 $ — $ — $ 12,281 Other revenue 111 — — 111 Total revenues 12,392 — — 12,392 Cost of product revenue 10,955 (1,829) — 9,126 Gross margin 1,437 1,829 — 3,266 Operating expenses: Selling, general and administrative 40,703 68 — 40,771 Research and development 45,463 14,757 (1,719) 58,501 Total operating expenses 86,166 14,825 (1,719) 99,272 Loss from operations (84,729) (12,996) 1,719 (96,006) Interest income 2,454 — — 2,454 Interest expense — (4,311) — (4,311) Other income, net 10,544 168 (81) 10,631 Loss before income taxes (71,731) (17,139) 1,638 (87,232) Income tax (expense) benefit — — — — Net loss (71,731) (17,139) 1,638 (87,232) Net loss per share - basic (1) $ (0.66) $ (0.16) $ 0.02 $ (0.80) Net loss per share - diluted (1) $ (0.66) $ (0.16) $ 0.02 $ (0.80) Weighted-average number of common shares used in computing net loss per share - basic: 109,098 — — 109,098 Weighted-average number of common shares used in computing net loss per share - diluted: 109,098 — — 109,098 Other comprehensive income (loss): Other comprehensive income (loss), net of tax (benefit) expense of $0.0 million for the three months ended September 30, 2023 137 — — 137 Total other comprehensive income (loss) 137 — — 137 Comprehensive loss $ (71,594) $ (17,139) $ 1,638 $ (87,095) (1) Due to differences in rounding to the nearest cent per basic or diluted share, totals may not equal the sum of the line items. For the nine months ended September 30, 2023 As Previously Reported Adjustments to Embedded Leases Other Adjustments As Restated Revenue: Product revenue, net $ 21,414 $ — $ — $ 21,414 Other revenue 249 — — 249 Total revenues 21,663 — — 21,663 Cost of product revenue 23,895 (2,560) — 21,335 Gross margin (2,232) 2,560 — 328 Operating expenses: Selling, general and administrative 118,406 294 — 118,700 Research and development 133,881 52 (2,397) 131,536 Total operating expenses 252,287 346 (2,397) 250,236 Gain from sale of priority review voucher, net 92,930 — — 92,930 Loss from operations (161,589) 2,214 2,397 (156,978) Interest income 7,961 — — 7,961 Interest expense (3) (12,328) — (12,331) Other income, net 30,152 106 (81) 30,177 Loss before income taxes (123,479) (10,008) 2,316 (131,171) Income tax (expense) benefit 80 — — 80 Net loss (123,399) (10,008) 2,316 (131,091) Net loss per share - basic $ (1.15) $ (0.09) $ 0.02 $ (1.23) Net loss per share - diluted $ (1.15) $ (0.09) $ 0.02 $ (1.23) Weighted-average number of common shares used in computing net loss per share - basic: 106,924 — — 106,924 Weighted-average number of common shares used in computing net loss per share - diluted: 106,924 — — 106,924 Other comprehensive income (loss): Other comprehensive income (loss), net of tax (benefit) expense of $0.0 million for the nine months ended September 30, 2023 1,843 — — 1,843 Total other comprehensive income (loss) 1,843 — — 1,843 Comprehensive loss $ (121,556) $ (10,008) $ 2,316 $ (129,248) (1) Due to differences in rounding to the nearest cent per basic or diluted share, totals may not equal the sum of the line items. Statements of Changes in Stockholders' Equity: Common stock Additional Accumulated other comprehensive income (loss) Accumulated Total Shares Amount As Previously Reported Balances at December 31, 2022 82,923 $ 830 $ 4,186,086 $ (4,070) $ (3,986,503) $ 196,343 Vesting of restricted stock 382 3 (198) — — (195) Exercise of stock options 3 — 7 — — 7 Purchase of shares under ESPP 62 1 226 — — 227 Issuance of common stock for private equity placement 23,000 230 130,061 — — 130,291 Stock-based compensation — — 5,843 — — 5,843 Other comprehensive income (loss) — — — 984 — 984 Net income (loss) — — — — 21,240 21,240 Balances at March 31, 2023 106,370 $ 1,064 $ 4,322,025 $ (3,086) $ (3,965,263) $ 354,740 Adjustments to Embedded Leases Balances at December 31, 2022 $ — $ — $ — $ — $ (59,700) $ (59,700) Vesting of restricted stock — — — — — — Exercise of stock options — — — — — — Purchase of shares under ESPP — — — — — — Issuance of common stock for private equity placement — — — — — — Stock-based compensation — — — — — — Other comprehensive income (loss) — — — — — — Net income (loss) — — — — (2,351) (2,351) Balances at March 31, 2023 — $ — $ — $ — $ (62,051) $ (62,051) Other Adjustments Balances at December 31, 2022 — — (98) — (2,212) (2,310) Vesting of restricted stock — — — — — — Exercise of stock options — — — — — — Purchase of shares under ESPP — — — — — — Issuance of common stock for private equity placement — — — — — — Stock-based compensation — — — — — — Other comprehensive income (loss) — — — — — — Net income (loss) — — — — 41 41 Balances at March 31, 2023 — $ — $ (98) $ — $ (2,171) $ (2,269) As Restated Balances at December 31, 2022 82,923 830 4,185,988 (4,070) (4,048,415) 134,333 Vesting of restricted stock 382 3 (198) — — (195) Exercise of stock options 3 — 7 — — 7 Purchase of shares under ESPP 62 1 226 — — 227 Issuance of common stock for private equity placement 23,000 230 130,061 — — 130,291 Stock-based compensation — — 5,843 — — 5,843 Other comprehensive income (loss) — — — 984 — 984 Net income (loss) — — — — 18,930 18,930 Balances at March 31, 2023 106,370 $ 1,064 $ 4,321,927 $ (3,086) $ (4,029,485) $ 290,420 Common stock Additional Accumulated Accumulated Total Shares Amount As Previously Reported Balances at March 31, 2023 106,370 $ 1,064 $ 4,322,025 $ (3,086) $ (3,965,263) $ 354,740 Vesting of restricted stock 65 1 (1) — — — Exercise of stock options 19 — 77 — — 77 Purchase of shares under ESPP — — — — — — Issuance of common stock for private equity placement — — — — — — Stock-based compensation — — 6,388 — — 6,388 Other comprehensive income (loss) — — — 722 — 722 Net income (loss) — — — — (72,908) (72,908) Balances at June 30, 2023 106,454 $ 1,065 $ 4,328,489 $ (2,364) $ (4,038,171) $ 289,019 Adjustments to Embedded Leases Balances at March 31, 2023 $ — $ — $ — $ — $ (62,051) $ (62,051) Vesting of restricted stock — — — — — — Exercise of stock options — — — — — — Purchase of shares under ESPP — — — — — — Issuance of common stock for private equity placement — — — — — — Stock-based compensation — — — — — — Other comprehensive income (loss) — — — — — — Net income (loss) — — — — 9,482 9,482 Balances at June 30, 2023 — $ — $ — $ — $ (52,569) $ (52,569) Other Adjustments Balances at March 31, 2023 — — (98) — (2,171) (2,269) Vesting of restricted stock — — — — — — Exercise of stock options — — — — — — Purchase of shares under ESPP — — — — — — Issuance of common stock for private equity placement — — — — — — Stock-based compensation — — — — — — Other comprehensive income (loss) — — — — — — Net income (loss) — — — — 637 637 Balances at June 30, 2023 — $ — $ (98) $ — $ (1,534) $ (1,632) As Restated Balances at March 31, 2023 106,370 1,064 4,321,927 (3,086) (4,029,485) 290,420 Vesting of restricted stock 65 1 (1) — — — Exercise of stock options 19 — 77 — — 77 Purchase of shares under ESPP — — — — — — Issuance of common stock for private equity placement — — — — — — Stock-based compensation — — 6,388 — — 6,388 Other comprehensive income (loss) — — — 722 — 722 Net income (loss) — — — — (62,789) (62,789) Balances at June 30, 2023 106,454 $ 1,065 $ 4,328,391 $ (2,364) $ (4,092,274) $ 234,818 Common stock Additional Accumulated Accumulated Total Shares Amount As previously reported Balances at June 30, 2023 106,454 $ 1,065 $ 4,328,489 $ (2,364) $ (4,038,171) $ 289,019 Vesting of restricted stock 566 6 (6) — — — Exercise of stock options 2 — 8 — — 8 Issuance of common stock — — (50) — — (50) Stock-based compensation expense — — 5,153 — — 5,153 Other comprehensive income (loss) — — — 137 — 137 Net income (loss) — — — — (71,731) (71,731) Balances at September 30, 2023 107,022 107,022 $ 1,071 $ 4,333,594 $ (2,227) $ (4,109,902) $ 222,536 Balances at Adjustments to Leases Balances at June 30, 2023 — — — — (52,569) (52,569) Vesting of restricted stock — — — — — — Exercise of stock options — — — — — — Issuance of common stock — — — — — — Stock-based compensation expense — — — — — — Other comprehensive income (loss) — — — — — — Net income (loss) — — — — (17,139) (17,139) Balances at September 30, 2023 — $ — $ — $ — $ (69,708) $ (69,708) Balances at Other Adjustments Balances at June 30, 2023 — — (98) — (1,534) (1,632) Vesting of restricted stock — — — — — — Exercise of stock options — — — — — — Issuance of common stock — — — — — — Stock-based compensation expense — — — — — — Other comprehensive income (loss) — — — — — — Net income (loss) — — — — 1,638 1,638 Balances at September 30, 2023 — $ — $ (98) $ — $ 104 $ 6 Balances at As Restated Balances at June 30, 2023 106,454 1,065 4,328,391 (2,364) (4,092,274) 234,818 Vesting of restricted stock 566 6 (6) — — — Exercise of stock options 2 — 8 — — 8 Issuance of common stock — — (50) — — (50) Stock-based compensation expense — — 5,153 — — 5,153 Other comprehensive income (loss) — — — 137 — 137 Net income (loss) — — — — (87,232) (87,232) Balances at September 30, 2023 107,022 $ 1,071 $ 4,333,496 $ (2,227) $ (4,179,506) $ 152,834 Consolidated Statement of Cash Flows For the nine months ended September 30, 2023 As Previously Reported Adjustments to Leases Other Adjustments As Restated Cash flows from operating activities: Net loss $ (123,399) $ (10,008) $ 2,316 $ (131,091) Adjustments to reconcile net loss to net cash used in operating activities: Depreciation and amortization 3,124 16,648 (112) 19,660 Stock-based compensation expense 16,013 — — 16,013 Noncash research and development expense (finance lease) — 22,223 — 22,223 Noncash operating lease expense — 23,965 — 23,965 Gain from sale of priority review voucher (92,930) — — (92,930) Excess inventory reserve 5,333 1,554 2,315 9,202 Other non-cash items 19 — 81 100 (Gain) loss on foreign currency exchange rates — (1,062) — (1,062) Changes in operating assets and liabilities: Accounts receivable (23,000) — 8,400 (14,600) Prepaid expenses and other assets (523) 2,640 — 2,117 Inventory (24,931) 1,651 (2,917) (26,197) Operating right of use assets 40,101 (40,101) — — Accounts payable (5,787) 7,183 316 1,712 Accrued expenses and other liabilities 7,125 583 (1,999) 5,709 Accrued interest payable under finance lease — 3,203 — 3,203 Operating lease liabilities (30,506) 11,820 — (18,686) Deferred revenue 8,152 — (8,400) (248) Net cash (used in) provided by operating activities (221,209) 40,299 — (180,910) Cash flows from investing activities: Purchase of property, plant and equipment (2,975) — — (2,975) Purchases of marketable securities (43,297) — — (43,297) Proceeds from maturities of marketable securities 99,521 — — 99,521 Proceeds from sales of marketable securities 5,853 — — 5,853 Purchase of intangible assets (868) — — (868) Proceeds from sale of priority review voucher 92,930 — — 92,930 Net cash provided by investing activities 151,164 — — 151,164 Cash flows from financing activities: Proceeds from exercise of stock options and ESPP contributions 93 — — 93 Proceeds from vesting of restricted stock (196) — — (196) Principal payments on finance lease — (40,299) — (40,299) Proceeds from the secondary public offering, net of issuance costs 130,072 — — 130,072 Net cash (used in) provided by financing activities 129,969 (40,299) — 89,670 Increase in cash, cash equivalents and restricted cash 59,924 — — 59,924 Cash, cash equivalents and restricted cash at beginning of year 158,445 — — 158,445 Cash, cash equivalents and restricted cash at end of year $ 218,369 $ — $ — $ 218,369 Reconciliation of cash, cash equivalents and restricted cash: Cash and cash equivalents $ 165,347 $ — $ — $ 165,347 Restricted cash included in receivables and other current assets 8,885 — — 8,885 Restricted cash included in restricted cash and other non-current assets 44,137 — — 44,137 Total cash, cash equivalents and restricted cash $ 218,369 $ — $ — $ 218,369 Supplemental cash flow disclosures: Right-of-use assets obtained in exchange for operating lease liabilities 44,819 (45,527) — (708) Purchases of property, plant and equipment included in accounts 941 — — 941 Offering expenses included in accounts payable and accrued expenses 248 — — 248 Right-of-use assets obtained in exchange for finance lease liabilities — 21,508 — 21,508 Increase (reduction) of right of use asset and associated operating lease liability due to lease reassessment 8,003 (8,003) — — Cash paid during the period for income taxes 5 — — 5

Description of the business (De

Description of the business (Details) $ in Thousands, shares in Millions			1 Months Ended				3 Months Ended						9 Months Ended
	Dec. 22, 2023 USD ($)	Dec. 19, 2023 shares	Sep. 30, 2024 USD ($) employee	Mar. 31, 2024 USD ($) tranche	Dec. 31, 2023 USD ($) shares	Aug. 31, 2023 USD ($)	Sep. 30, 2024 USD ($)	Jun. 30, 2024 USD ($)	Mar. 31, 2024 USD ($) tranche	Sep. 30, 2023 USD ($)	Jun. 30, 2023 USD ($)	Mar. 31, 2023 USD ($)	Sep. 30, 2024 USD ($)	Sep. 30, 2023 USD ($)
Subsidiary, Sale of Stock [Line Items]
Number of tranches | tranche				4					4
Number of employees eliminated | employee			94
Plans to reduce workforce, as a percent			25%
Accumulated deficit			$ 4,472,333		$ 4,260,328		$ 4,472,333						$ 4,472,333
Net income (loss)							60,808	$ 81,393	$ 69,804	$ 87,232	$ 62,789	$ (18,930)	212,003	$ 131,091
Net cash used in operating activities													209,856	$ 180,910
Cash, cash equivalents and marketable securities			$ 70,700				$ 70,700						$ 70,700
Term Loan
Subsidiary, Sale of Stock [Line Items]
Debt instrument term				5 years
Line of credit				$ 175,000					$ 175,000
At The Market Offering
Subsidiary, Sale of Stock [Line Items]
Proceeds from stock offering						$ 125,000
December Underwriting Agreement
Subsidiary, Sale of Stock [Line Items]
Proceeds from stock offering	$ 118,100				$ 118,100
Shares of common stock sold (in shares) | shares		83.3			83.3

Basis of presentation, princi_3

Basis of presentation, principles of consolidation and significant accounting policies (Details)	9 Months Ended
	Sep. 30, 2024 segment
Accounting Policies [Abstract]
Number of operating segments	1

Product revenue and reserves -

Product revenue and reserves - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Revenue from External Customer [Line Items]
Product revenue, net	$ 10,612	$ 12,281	$ 45,274	$ 21,414
Revenue from Contract with Customer Benchmark | Customer Concentration Risk | Six Individual Customers
Revenue from External Customer [Line Items]
Concentration risk, percentage			84%
Revenue from Contract with Customer Benchmark | Customer Concentration Risk | Two Individual Customer
Revenue from External Customer [Line Items]
Concentration risk, percentage				89%

Product revenue and reserves _2

Product revenue and reserves - Summary of Product Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Revenue from External Customer [Line Items]
Product revenue, net	$ 10,612	$ 12,281	$ 45,274	$ 21,414
ZYNTEGLO
Revenue from External Customer [Line Items]
Product revenue, net	5,493	4,851	35,212	9,031
LYFGENIA
Revenue from External Customer [Line Items]
Product revenue, net	2,632	0	2,632	0
SKYSONA
Revenue from External Customer [Line Items]
Product revenue, net	$ 2,487	$ 7,430	$ 7,430	$ 12,383

Product revenue and reserves _3

Product revenue and reserves - Rebate Liability (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2024 USD ($)
Contract with Customer, Refund Liability [Roll Forward]
Balance at December 31, 2023	$ 5,365
Provision for rebates	8,506
Payments/credits	0
Balance at September 30, 2024	$ 13,871

Fair value measurements - Recor

Fair value measurements - Recorded Amount of Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) - Fair Value, Measurements, Recurring - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Assets:
Cash and cash equivalents	$ 70,651	$ 221,755
Beneficiary interest in factored invoices	1,062	560
Other non-current liabilities
Total	72,700	222,315
Warrants
Other non-current liabilities
Warrant liability	987
Quoted prices in active markets (Level 1)
Assets:
Cash and cash equivalents	70,651	221,755
Beneficiary interest in factored invoices	0	0
Other non-current liabilities
Total	70,651	221,755
Quoted prices in active markets (Level 1) | Warrants
Other non-current liabilities
Warrant liability	0
Significant other observable inputs (Level 2)
Assets:
Cash and cash equivalents	0	0
Beneficiary interest in factored invoices	0	0
Other non-current liabilities
Total	0	0
Significant other observable inputs (Level 2) | Warrants
Other non-current liabilities
Warrant liability	0
Significant unobservable inputs (Level 3)
Assets:
Cash and cash equivalents	0	0
Beneficiary interest in factored invoices	1,062	560
Other non-current liabilities
Total	2,049	$ 560
Significant unobservable inputs (Level 3) | Warrants
Other non-current liabilities
Warrant liability	$ 987

Fair value measurements - Narra

Fair value measurements - Narrative (Details) - Common Stock Warrants	Sep. 30, 2024 $ / shares yr	Aug. 13, 2024 $ / shares	Mar. 15, 2024 $ / shares
Class of Warrant or Right [Line Items]
Exercise price of warrants (in dollars per share)		$ 1.03	$ 1.45
Expected Dividend Rate
Class of Warrant or Right [Line Items]
Warrants and rights outstanding, measurement input	0
Measurement Input, Exercise Price | Minimum
Class of Warrant or Right [Line Items]
Warrants and rights outstanding, measurement input	0.50
Measurement Input, Exercise Price | Maximum
Class of Warrant or Right [Line Items]
Warrants and rights outstanding, measurement input	1.03
Measurement Input, Share Price
Class of Warrant or Right [Line Items]
Warrants and rights outstanding, measurement input	0.52
Measurement Input, Price Volatility
Class of Warrant or Right [Line Items]
Warrants and rights outstanding, measurement input	0.857
Risk Free Interest Rate
Class of Warrant or Right [Line Items]
Warrants and rights outstanding, measurement input	0.037
Measurement Input, Expected Term
Class of Warrant or Right [Line Items]
Warrants and rights outstanding, measurement input | yr	7

Fair value measurements - Facto

Fair value measurements - Factoring Agreement Reconciliation of Beginning and Ending Balances (Details) - Beneficial Interest $ in Thousands	9 Months Ended
	Sep. 30, 2024 USD ($)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at December 31, 2023	$ 560
Beneficiary interest obtained in transferred invoices	4,850
Gross proceeds from previously transferred invoices	(4,240)
Accrual for factor reserve deficiency	(26)
Accrual for anticipated loss on sale of invoices	(82)
Balance at September 30, 2024	$ 1,062

Fair value measurements - Commo

Fair value measurements - Common Stock Warrants Reconciliation of Beginning and Ending Balances (Details) - Common Stock Warrants $ in Thousands	9 Months Ended
	Sep. 30, 2024 USD ($)
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at December 31, 2023	$ 0
Warrant modification and reclassification to liabilities	2,100
Change in fair value	(1,113)
Balance at September 30, 2024	$ 987

Inventory (Details)

Inventory (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Inventory Disclosure [Abstract]
Raw materials	$ 2,965	$ 2,329
Work in progress	48,649	17,375
Finished goods	2,330	3,215
Inventory	$ 53,944	$ 22,919

Factoring agreement (Details)

Factoring agreement (Details) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2024 USD ($)	Sep. 30, 2024 USD ($)
Receivables [Abstract]
Percentage of invoice sold	100%	100%
Upfront purchase price as a percentage of invoice amount	90%	90%
Remaining percentage of invoice amount payable upon receipt of full payment	10%	10%
Cash receipts collected prior to consideration	$ 15.2	$ 50.6
Due to factor, value derecognized	10.6	43.7
Beneficiary interest obtained in transferred invoices	1.2	4.9
Proceeds from previously transferred invoices, net of fees	0.7	3.5
Uncollectable amounts, net of accrued fees	0.1	0.1
Maximum loss exposure	1.2	1.2
Loss on sale of invoice	0.5	1.4
Servicing fees	$ 0.3	$ 0.8

Accrued expenses and other cu_3

Accrued expenses and other current liabilities - Schedule of Accrued Expenses and Other Current Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Payables and Accruals [Abstract]
Accrued CMO and CRO costs	$ 21,735	$ 24,824
Accrued employee compensation	15,375	19,972
Accrued rebates	13,998	5,365
Accrued goods and services	1,814	8,391
Accrued professional fees	10,070	2,531
Other sublease rent liability	3,379	3,310
Accrued refund liability	0	5,600
Other	3,808	3,195
Total accrued expenses and other current liabilities	$ 70,179	$ 73,188

Term loan debt (Details)

Term loan debt (Details) $ / shares in Units, $ in Thousands, shares in Millions			3 Months Ended		9 Months Ended
	Aug. 13, 2024 USD ($) $ / shares	Mar. 15, 2024 USD ($) tranche $ / shares	Sep. 30, 2024 USD ($) shares	Sep. 30, 2023 USD ($)	Sep. 30, 2024 USD ($) shares	Sep. 30, 2023 USD ($)	Mar. 31, 2024 USD ($) yr
Line of Credit Facility [Line Items]
Interest expense				$ 4,311		$ 12,331
The Warrants
Line of Credit Facility [Line Items]
Exercise price of warrants (in dollars per share) | $ / shares	$ 1.03	$ 1.45
Relative fair value allocated to the initial warrants							$ 2,700
Value of warrants issued in relation to debt	10 days
Number of securities called by warrants (in shares) | shares			2.6		2.6
Warrants and rights outstanding, contractual term (in years)			7 years		7 years
Increase in fair value of debt discount	$ 200
Fair value			$ 1,000		$ 1,000
Gain on fair value					1,100
The Warrants | Expected Dividend Rate
Line of Credit Facility [Line Items]
Warrants and rights outstanding, measurement input							0
The Warrants | Measurement Input, Price Volatility
Line of Credit Facility [Line Items]
Warrants and rights outstanding, measurement input							0.811
The Warrants | Risk Free Interest Rate
Line of Credit Facility [Line Items]
Warrants and rights outstanding, measurement input							0.043
The Warrants | Measurement Input, Expected Term
Line of Credit Facility [Line Items]
Warrants and rights outstanding, measurement input | yr							7
Secured Debt | Line of Credit
Line of Credit Facility [Line Items]
Minimum cash coverage as a percentage of outstanding principal	45%
Percentage of aggregate original principal		5%
Secured Debt | Term Loan Facility | Line of Credit
Line of Credit Facility [Line Items]
Maximum borrowing capacity		$ 175,000
Number of tranches | tranche		4
Proceeds from long-term lines of credit		$ 75,000
Debt issuance costs, gross		3,500
Debt issuance costs, net		2,700
Original issue discount		$ 800
Discount percentage		1%
Effective interest rate	16%						15.70%
Interest expense			$ 2,800		$ 6,100
Secured Debt | Term Loan Facility | Prime Rate | Line of Credit
Line of Credit Facility [Line Items]
Variable rate	1.45%
Secured Debt | Term Loan Facility | Prime Floor Rate | Line of Credit
Line of Credit Facility [Line Items]
Variable rate	9.95%
Secured Debt | Term Loan Facility | Paid In Kind | Line of Credit
Line of Credit Facility [Line Items]
PIK interest	2.45%
Secured Debt | Term Loan Facility Tranche Two | Line of Credit
Line of Credit Facility [Line Items]
Maximum borrowing capacity	$ 25,000
Debt covenant, minimum gross cash proceeds	$ 75,000
Period immediately following achievement	30 days
Secured Debt | Term Loan Facility Tranche Three | Line of Credit
Line of Credit Facility [Line Items]
Maximum borrowing capacity	$ 25,000
Period immediately following achievement	30 days
Debt covenant, product delivery period	6 months
Secured Debt | Term Loan Facility Tranche Three | Proceeds Received December 20, 2024 | Line of Credit
Line of Credit Facility [Line Items]
Debt covenant, minimum gross cash proceeds	$ 100,000
Secured Debt | Term Loan Facility Tranche Three | Proceeds Received June 30, 2025 | Line of Credit
Line of Credit Facility [Line Items]
Debt covenant, minimum gross cash proceeds	125,000
Secured Debt | Term Loan Facility Tranche Four | Line of Credit
Line of Credit Facility [Line Items]
Maximum borrowing capacity	$ 50,000

Leases - Narrative (Details)

Leases - Narrative (Details) - USD ($) $ in Millions	1 Months Ended		9 Months Ended
	Sep. 30, 2024	Aug. 31, 2024	Sep. 30, 2024
Lessee, Lease, Description [Line Items]
Written notice of termination term provided to lessor		12 months
Extended embedded lease term (in years)	5 years
Drug Product Manufacturing Facility And Quality Testing
Lessee, Lease, Description [Line Items]
Increase (decrease) in finance lease right of use asset			$ 10.3
Drug Substance Manufacturing Facility
Lessee, Lease, Description [Line Items]
Increase (decrease) in finance lease right of use asset			$ (12.1)

Leases - Summary of Operating L

Leases - Summary of Operating Lease Costs and Other Information (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Finance leases
Interest expense	$ 2,364	$ 4,311	$ 9,421	$ 12,327
Amortization expense	14,193	6,459	43,896	16,903
Total fixed finance lease cost	16,557	10,770	53,317	29,230
Operating leases
Fixed lease cost	9,486	11,470	28,459	34,411
Variable lease cost	9,129	4,186	22,128	16,140
Short-term lease cost	98	43	265	140
Total lease cost	35,270	26,469	104,169	79,921
Operating sublease income	$ 10,219	$ 9,742	30,825	30,223
Cash paid in the measurement of lease liabilities
Operating cash flows used for operating leases			15,323	18,686
Operating cash flows used for finance leases			1,411	9,125
Financing cash flows for finance leases			$ 69,576	$ 40,299
Lease, Cost [Abstract]
Weighted average remaining lease term - finance leases	1 year 11 months 1 day	1 year 8 months 19 days	1 year 11 months 1 day	1 year 8 months 19 days
Weighted average discount rate - finance leases	12.56%	14.49%	12.56%	14.49%
Weighted average remaining lease term - operating leases	6 years 3 months 25 days	7 years 2 months 15 days	6 years 3 months 25 days	7 years 2 months 15 days
Weighted average discount rate - operating leases	6.97%	7.02%	6.97%	7.02%

Leases - Schedule of Future Min

Leases - Schedule of Future Minimum Commitments (Details) $ in Thousands	Sep. 30, 2024 USD ($)
Operating Leases
Remainder of 2024	$ 9,151
2025	37,084
2026	35,719
2027	36,742
2028	37,795
2029 and thereafter	81,986
Total	238,477
Less: Imputed Interest	(45,910)
Present Value of Lease Liabilities	192,567
Financing Leases
Remainder of 2024	57,718
2025	43,068
2026	2,738
2027	1,673
2028	685
2029 and thereafter	0
Total	105,882
Less: Imputed Interest	(4,036)
Present Value of Lease Liabilities	$ 101,846

Commitments and contingencies -

Commitments and contingencies - Narrative (Details) $ in Thousands	Apr. 15, 2024 USD ($) patent	Mar. 31, 2025	Dec. 31, 2024	Sep. 30, 2024 USD ($)
Long-Term Purchase Commitment [Line Items]
Purchase obligation				$ 60,475
Pending Litigation | SRT Demand For Arbitration
Long-Term Purchase Commitment [Line Items]
Number of patents | patent	2
Damages sought	$ 1,500
Forecast
Long-Term Purchase Commitment [Line Items]
Lease period		4 years	3 years

Commitments and contingencies_2

Commitments and contingencies - Schedule of Non-cancelable Contractual Obligations (Detail) $ in Thousands	Sep. 30, 2024 USD ($)
Commitments and Contingencies Disclosure [Abstract]
Remainder of 2024	$ 294
2025	15,047
2026	18,733
2027	18,733
2028	7,668
2029 and thereafter	0
Total purchase commitments	$ 60,475

Equity (Details)

Equity (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions					1 Months Ended
	Dec. 22, 2023	Dec. 19, 2023	Jan. 23, 2023	Jan. 18, 2023	Dec. 31, 2023	Aug. 31, 2023
January Underwriting Agreement
Subsidiary, Sale of Stock [Line Items]
Shares of common stock sold (in shares)				20
Common stock price per share (in dollars per share)				$ 6
Proceeds from stock offering			$ 130.5
Inclusive of Shares Pursuant to Over Allotment Option Granted
Subsidiary, Sale of Stock [Line Items]
Shares of common stock sold (in shares)		12.5		3
Option to purchase additional shares, exercise period		30 days		30 days
At The Market Offering
Subsidiary, Sale of Stock [Line Items]
Proceeds from stock offering						$ 125
Value of shares available for sale						$ 125
December Underwriting Agreement
Subsidiary, Sale of Stock [Line Items]
Shares of common stock sold (in shares)		83.3			83.3
Common stock price per share (in dollars per share)		$ 1.50
Proceeds from stock offering	$ 118.1				$ 118.1

Stock-based compensation - Narr

Stock-based compensation - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Jun. 30, 2021	Jun. 30, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 2,701	$ 4,868	$ 9,669	$ 16,013
Amount capitalized			$ 1,000	1,400
Stock option share exercised (in shares)			0
Employee stock purchase plan and other
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 26	$ 194	$ 109	$ 269
Common shares reserved for future issuance (in shares)						200,000
Increase in shares authorized (in shares)					1,400,000
Shares of common stock issued under plan (in shares)			100,000
Employee stock purchase plan and other | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares of common stock issued under plan (in shares)				100,000
2023 Incentive Award Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares available for issuance (in shares)	1,500,000		1,500,000
2021 Incentive Award Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares available for issuance (in shares)	600,000		600,000

Stock-based compensation - Summ

Stock-based compensation - Summary of Stock-Based Compensation Expense by Award Type (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 2,701	$ 4,868	$ 9,669	$ 16,013
Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	920	1,758	3,343	5,192
Restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	1,755	2,916	6,217	10,552
Employee stock purchase plan and other
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 26	$ 194	$ 109	$ 269

Stock-based compensation - Sche

Stock-based compensation - Schedule of Stock-Based Compensation Expense by Classification (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 2,701	$ 4,868	$ 9,669	$ 16,013
Cost of product revenue
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	102	342	882	435
Selling, general and administrative
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	1,650	2,461	5,783	7,503
Research and development
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	681	2,065	2,736	8,075
Restructuring Expenses
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 268	$ 0	$ 268	$ 0

Stock-based compensation - Su_2

Stock-based compensation - Summary of Stock Option Activity Under Plan (Details)	9 Months Ended
	Sep. 30, 2024 $ / shares shares
Shares (in thousands)
Outstanding at beginning of period (in shares) | shares	4,227,000
Granted (in shares) | shares	3,010,000
Exercised (in shares) | shares	0
Canceled, forfeited, or expired (in shares) | shares	(905,000)
Outstanding at end of period (in shares) | shares	6,332,000
Exercisable at end of period (in shares) | shares	2,290,000
Vested and expected to vest at end of period (in shares) | shares	6,332,000
Weighted- average exercise price per share
Outstanding at beginning of period (in dollars per share) | $ / shares	$ 14.16
Granted (in dollars per share) | $ / shares	1.47
Exercised (in dollars per share) | $ / shares	0
Canceled, forfeited, or expired (in dollars per share) | $ / shares	10.52
Outstanding at end of period (in dollars per share) | $ / shares	8.66
Exercisable at end of period (in dollars per share) | $ / shares	18.54
Vested and expected to vest at end of period (in dollars per share) | $ / shares	$ 8.66

Stock-based compensation - Su_3

Stock-based compensation - Summary of Restricted Stock Units (Details) - Restricted stock units shares in Thousands	9 Months Ended
	Sep. 30, 2024 $ / shares shares
Shares (in thousands)
Unvested balance at beginning of period (in shares) | shares	4,207
Granted (in shares) | shares	3,357
Vested (in shares) | shares	(1,083)
Forfeited (in shares) | shares	(907)
Unvested balance at end of period (in shares) | shares	5,574
Weighted- average grant date fair value
Unvested balance at beginning of period (in dollars per share) | $ / shares	$ 6.08
Granted (in dollars per share) | $ / shares	1.23
Vested (in dollars per share) | $ / shares	7.08
Forfeited (in dollars per share) | $ / shares	4.05
Unvested balance at end of period (in dollars per share) | $ / shares	$ 3.29

Income taxes (Details)

Income taxes (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Income Tax Disclosure [Abstract]
Income tax benefit	$ 58	$ 0	$ 37	$ 80

Net loss per share - Anti-dilut

Net loss per share - Anti-dilutive shares (Detail) - shares shares in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Common stock equivalents excluded from the calculation of diluted net loss per share (in shares)	15,694	10,069	15,694	10,069
Outstanding stock options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Common stock equivalents excluded from the calculation of diluted net loss per share (in shares)	7,473	5,875	7,473	5,875
Restricted stock units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Common stock equivalents excluded from the calculation of diluted net loss per share (in shares)	5,574	4,194	5,574	4,194
Warrants
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Common stock equivalents excluded from the calculation of diluted net loss per share (in shares)	2,586	0	2,586	0
ESPP shares and other
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Common stock equivalents excluded from the calculation of diluted net loss per share (in shares)	61	0	61	0

Net loss per share - Narrative

Net loss per share - Narrative (Details) - $ / shares	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Earnings Per Share [Abstract]
Basic EPS (In dollars per share)	$ (0.31)	$ (0.80)	$ (1.10)	$ (1.23)
Diluted EPS (in dollars per share)	$ (0.31)	$ (0.80)	$ (1.10)	$ (1.23)

Reduction in workforce - Narrat

Reduction in workforce - Narrative (Details) $ in Thousands	1 Months Ended	3 Months Ended		9 Months Ended
	Sep. 30, 2024 USD ($) employee	Sep. 30, 2024 USD ($)	Sep. 30, 2023 USD ($)	Sep. 30, 2024 USD ($)	Sep. 30, 2023 USD ($)
Restructuring Cost and Reserve [Line Items]
Number of employees eliminated | employee	94
Plans to reduce workforce, as a percent	25%
Restructuring expenses		$ 2,811	$ 0	$ 2,811	$ 0
Restricted stock units
Restructuring Cost and Reserve [Line Items]
Non-cash stock based compensation expense	$ 300	$ 300		300
Employee Severance
Restructuring Cost and Reserve [Line Items]
Restructuring expenses				$ 2,543

Reduction in workforce - Accrue

Reduction in workforce - Accrued Liabilities Activity (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Restructuring Cost and Reserve [Line Items]
Cash expenditure charges	$ 2,811	$ 0	$ 2,811	$ 0
Employee Severance
Restructuring Cost and Reserve [Line Items]
Cash expenditure charges			2,543
Amount paid through September 30, 2024			0
Amounts accrued at September 30, 2024			$ 2,543

Restatement of Previously Iss_3

Restatement of Previously Issued Financial Statements - Schedule of Operations and Comprehensive Loss (Details) - USD ($) $ / shares in Units, shares in Thousands, $ 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
Revenue:
Product revenue, net	$ 10,612			$ 12,281			$ 45,274	$ 21,414
Other revenue	0			111			12	249
Total revenues	10,612			12,392			45,286	21,663
Cost of product revenue	11,781			9,126			66,591	21,335
Gross margin	(1,169)			3,266			(21,305)	328
Operating expenses:
Selling, general and administrative	39,765			40,771			136,479	118,700
Research and development	23,174			58,501			73,408	131,536
Total operating expenses	65,750			99,272			212,698	250,236
Gain from sale of priority review voucher, net	0			0			0	92,930
Loss from operations	(66,919)			(96,006)			(234,003)	(156,978)
Interest income	1,640			2,454			7,056	7,961
Interest expense				(4,311)				(12,331)
Other income, net	10,191			10,631			31,782	30,177
Loss before income taxes	(60,866)			(87,232)			(212,040)	(131,171)
Income tax (expense) benefit	58			0			37	80
Net loss	$ (60,808)	$ (81,393)	$ (69,804)	$ (87,232)	$ (62,789)	$ 18,930	$ (212,003)	$ (131,091)
Net loss per share - basic (in dollars per share)	$ (0.31)			$ (0.80)			$ (1.10)	$ (1.23)
Net loss per share - diluted (in dollars per share)	$ (0.31)			$ (0.80)			$ (1.10)	$ (1.23)
Weighted-average number of common shares used in computing net loss per share - basic (in shares)	193,893			109,098			193,588	106,924
Weighted-average number of common shares used in computing net loss per share - diluted (in shares)	193,893			109,098			193,588	106,924
Other comprehensive income (loss):
Total other comprehensive income (loss)	$ 611	$ (14)	$ (312)	$ 137	722	984	$ 285	$ 1,843
Comprehensive loss	(60,197)			(87,095)			(211,718)	(129,248)
Other comprehensive income (loss), tax	$ 0			0			$ 0	0
As Previously Reported
Revenue:
Product revenue, net				12,281				21,414
Other revenue				111				249
Total revenues				12,392				21,663
Cost of product revenue				10,955				23,895
Gross margin				1,437				(2,232)
Operating expenses:
Selling, general and administrative				40,703				118,406
Research and development				45,463				133,881
Total operating expenses				86,166				252,287
Gain from sale of priority review voucher, net								92,930
Loss from operations				(84,729)				(161,589)
Interest income				2,454				7,961
Interest expense				0				(3)
Other income, net				10,544				30,152
Loss before income taxes				(71,731)				(123,479)
Income tax (expense) benefit				0				80
Net loss				$ (71,731)	(72,908)	21,240		$ (123,399)
Net loss per share - basic (in dollars per share)				$ (0.66)				$ (1.15)
Net loss per share - diluted (in dollars per share)				$ (0.66)				$ (1.15)
Weighted-average number of common shares used in computing net loss per share - basic (in shares)				109,098				106,924
Weighted-average number of common shares used in computing net loss per share - diluted (in shares)				109,098				106,924
Other comprehensive income (loss):
Total other comprehensive income (loss)				$ 137				$ 1,843
Comprehensive loss				(71,594)				(121,556)
Revision of Prior Period, Error Correction, Adjustment | Adjustments to Embedded Leases
Revenue:
Product revenue, net				0				0
Other revenue				0				0
Total revenues				0				0
Cost of product revenue				(1,829)				(2,560)
Gross margin				1,829				2,560
Operating expenses:
Selling, general and administrative				68				294
Research and development				14,757				52
Total operating expenses				14,825				346
Gain from sale of priority review voucher, net								0
Loss from operations				(12,996)				2,214
Interest income				0				0
Interest expense				(4,311)				(12,328)
Other income, net				168				106
Loss before income taxes				(17,139)				(10,008)
Income tax (expense) benefit				0				0
Net loss				$ (17,139)	9,482	(2,351)		$ (10,008)
Net loss per share - basic (in dollars per share)				$ (0.16)				$ (0.09)
Net loss per share - diluted (in dollars per share)				$ (0.16)				$ (0.09)
Weighted-average number of common shares used in computing net loss per share - basic (in shares)				0				0
Weighted-average number of common shares used in computing net loss per share - diluted (in shares)				0				0
Other comprehensive income (loss):
Total other comprehensive income (loss)				$ 0				$ 0
Comprehensive loss				(17,139)				(10,008)
Revision of Prior Period, Error Correction, Adjustment | Other Adjustments
Revenue:
Product revenue, net				0				0
Other revenue				0				0
Total revenues				0				0
Cost of product revenue				0				0
Gross margin				0				0
Operating expenses:
Selling, general and administrative				0				0
Research and development				(1,719)				(2,397)
Total operating expenses				(1,719)				(2,397)
Gain from sale of priority review voucher, net								0
Loss from operations				1,719				2,397
Interest income				0				0
Interest expense				0				0
Other income, net				(81)				(81)
Loss before income taxes				1,638				2,316
Income tax (expense) benefit				0				0
Net loss				$ 1,638	$ 637	$ 41		$ 2,316
Net loss per share - basic (in dollars per share)				$ 0.02				$ 0.02
Net loss per share - diluted (in dollars per share)				$ 0.02				$ 0.02
Weighted-average number of common shares used in computing net loss per share - basic (in shares)				0				0
Weighted-average number of common shares used in computing net loss per share - diluted (in shares)				0				0
Other comprehensive income (loss):
Total other comprehensive income (loss)				$ 0				$ 0
Comprehensive loss				$ 1,638				$ 2,316

Restatement of Previously Iss_4

Restatement of Previously Issued Financial Statements - Schedule of Changes in Stockholders' Equity (Details) - 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
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Beginning balance (in shares)			192,772,000				192,772,000
Beginning balance	$ 52,981	$ 131,046	$ 194,537	$ 234,818	$ 290,420	$ 134,333	$ 194,537	$ 134,333
Vesting of restricted stock units	0	0	0	0	0	(195)
Exercise of stock options (in shares)							0
Exercise of stock options				8	77	7
Purchase of common stock under employee stock purchase plan (ESPP)		81				227
Issuance of common stock				(50)		130,291
Stock-based compensation expense	3,375	3,261	4,054	5,153	6,388	5,843
Other comprehensive income (loss)				137	722	984
Net income (loss)	$ (60,808)	(81,393)	(69,804)	(87,232)	(62,789)	18,930	$ (212,003)	(131,091)
Ending balance, shares (in shares)	193,917,000						193,917,000
Ending balance	$ (5,786)	$ 52,981	$ 131,046	$ 152,834	$ 234,818	$ 290,420	$ (5,786)	$ 152,834
Common Shares
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Beginning balance (in shares)	193,856,000	193,583,000	192,772,000	106,454,000	106,370,000	82,923,000	192,772,000	82,923,000
Beginning balance	$ 1,916	$ 1,913	$ 1,905	$ 1,065	$ 1,064	$ 830	$ 1,905	$ 830
Vesting of restricted stock units (in shares)	61,000	185,000	811,000	566,000	65,000	382,000
Vesting of restricted stock units	$ 1	$ 2	$ 8	$ 6	$ 1	$ 3
Exercise of stock options (in shares)				2,000	19,000	3,000
Purchase of common stock under employee stock purchase plan (ESPP) (in shares)		88,000				62,000
Purchase of common stock under employee stock purchase plan (ESPP)		$ 1				$ 1
Issuance of common stock (in shares)						23,000,000
Issuance of common stock						$ 230
Ending balance, shares (in shares)	193,917,000	193,856,000	193,583,000	107,022,000	106,454,000	106,370,000	193,917,000	107,022,000
Ending balance	$ 1,917	$ 1,916	$ 1,913	$ 1,071	$ 1,065	$ 1,064	$ 1,917	$ 1,071
Additional paid-in capital
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Beginning balance	4,464,712	4,461,373	4,454,756	4,328,391	4,321,927	4,185,988	4,454,756	4,185,988
Vesting of restricted stock units	(1)	(2)	(8)	(6)	(1)	(198)
Exercise of stock options				8	77	7
Purchase of common stock under employee stock purchase plan (ESPP)		80				226
Issuance of common stock				(50)		130,061
Stock-based compensation expense	3,375	3,261	4,054	5,153	6,388	5,843
Ending balance	4,466,141	4,464,712	4,461,373	4,333,496	4,328,391	4,321,927	4,466,141	4,333,496
Accumulated other comprehensive income (loss)
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Beginning balance	(2,122)	(2,108)	(1,796)	(2,364)	(3,086)	(4,070)	(1,796)	(4,070)
Other comprehensive income (loss)				137	722	984
Ending balance	(1,511)	(2,122)	(2,108)	(2,227)	(2,364)	(3,086)	(1,511)	(2,227)
Accumulated deficit
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Beginning balance	(4,411,525)	(4,330,132)	(4,260,328)	(4,092,274)	(4,029,485)	(4,048,415)	(4,260,328)	(4,048,415)
Net income (loss)	(60,808)	(81,393)	(69,804)	(87,232)	(62,789)	18,930
Ending balance	$ (4,472,333)	$ (4,411,525)	$ (4,330,132)	(4,179,506)	(4,092,274)	(4,029,485)	$ (4,472,333)	(4,179,506)
As Previously Reported
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Beginning balance				289,019	354,740	196,343		196,343
Vesting of restricted stock units				0	0	(195)
Exercise of stock options				8	77	7
Purchase of common stock under employee stock purchase plan (ESPP)						227
Issuance of common stock				(50)		130,291
Stock-based compensation expense				5,153	6,388	5,843
Other comprehensive income (loss)				137	722	984
Net income (loss)				(71,731)	(72,908)	21,240		(123,399)
Ending balance				$ 222,536	$ 289,019	$ 354,740		$ 222,536
As Previously Reported | Common Shares
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Beginning balance (in shares)				106,454,000	106,370,000	82,923,000		82,923,000
Beginning balance				$ 1,065	$ 1,064	$ 830		$ 830
Vesting of restricted stock units (in shares)				566,000	65,000	382,000
Vesting of restricted stock units				$ 6	$ 1	$ 3
Exercise of stock options (in shares)				2,000	19,000	3,000
Purchase of common stock under employee stock purchase plan (ESPP) (in shares)						62,000
Purchase of common stock under employee stock purchase plan (ESPP)						$ 1
Issuance of common stock (in shares)						23,000,000
Issuance of common stock						$ 230
Ending balance, shares (in shares)				107,022,000	106,454,000	106,370,000		107,022,000
Ending balance				$ 1,071	$ 1,065	$ 1,064		$ 1,071
As Previously Reported | Additional paid-in capital
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Beginning balance				4,328,489	4,322,025	4,186,086		4,186,086
Vesting of restricted stock units				(6)	(1)	(198)
Exercise of stock options				8	77	7
Purchase of common stock under employee stock purchase plan (ESPP)						226
Issuance of common stock				(50)		130,061
Stock-based compensation expense				5,153	6,388	5,843
Ending balance				4,333,594	4,328,489	4,322,025		4,333,594
As Previously Reported | Accumulated other comprehensive income (loss)
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Beginning balance				(2,364)	(3,086)	(4,070)		(4,070)
Other comprehensive income (loss)				137	722	984
Ending balance				(2,227)	(2,364)	(3,086)		(2,227)
As Previously Reported | Accumulated deficit
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Beginning balance				(4,038,171)	(3,965,263)	(3,986,503)		(3,986,503)
Net income (loss)				(71,731)	(72,908)	21,240
Ending balance				(4,109,902)	(4,038,171)	(3,965,263)		(4,109,902)
Revision of Prior Period, Error Correction, Adjustment | Adjustments to Embedded Leases
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Beginning balance				(52,569)	(62,051)	(59,700)		(59,700)
Net income (loss)				(17,139)	9,482	(2,351)		(10,008)
Ending balance				(69,708)	(52,569)	(62,051)		(69,708)
Revision of Prior Period, Error Correction, Adjustment | Other Adjustments
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Beginning balance				(1,632)	(2,269)	(2,310)		(2,310)
Net income (loss)				1,638	637	41		2,316
Ending balance				$ 6	$ (1,632)	$ (2,269)		$ 6
Revision of Prior Period, Error Correction, Adjustment | Common Shares | Adjustments to Embedded Leases
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Beginning balance (in shares)				0	0	0		0
Beginning balance				$ 0	$ 0	$ 0		$ 0
Ending balance, shares (in shares)				0	0	0		0
Ending balance				$ 0	$ 0	$ 0		$ 0
Revision of Prior Period, Error Correction, Adjustment | Common Shares | Other Adjustments
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Beginning balance (in shares)				0	0	0		0
Beginning balance				$ 0	$ 0	$ 0		$ 0
Ending balance, shares (in shares)				0	0	0		0
Ending balance				$ 0	$ 0	$ 0		$ 0
Revision of Prior Period, Error Correction, Adjustment | Additional paid-in capital | Adjustments to Embedded Leases
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Beginning balance				0	0	0		0
Ending balance				0	0	0		0
Revision of Prior Period, Error Correction, Adjustment | Additional paid-in capital | Other Adjustments
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Beginning balance				(98)	(98)	(98)		(98)
Ending balance				(98)	(98)	(98)		(98)
Revision of Prior Period, Error Correction, Adjustment | Accumulated other comprehensive income (loss) | Adjustments to Embedded Leases
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Beginning balance				0	0	0		0
Ending balance				0	0	0		0
Revision of Prior Period, Error Correction, Adjustment | Accumulated other comprehensive income (loss) | Other Adjustments
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Beginning balance				0	0	0		0
Ending balance				0	0	0		0
Revision of Prior Period, Error Correction, Adjustment | Accumulated deficit | Adjustments to Embedded Leases
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Beginning balance				(52,569)	(62,051)	(59,700)		(59,700)
Net income (loss)				(17,139)	9,482	(2,351)
Ending balance				(69,708)	(52,569)	(62,051)		(69,708)
Revision of Prior Period, Error Correction, Adjustment | Accumulated deficit | Other Adjustments
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Beginning balance				(1,534)	(2,171)	(2,212)		(2,212)
Net income (loss)				1,638	637	41
Ending balance				$ 104	$ (1,534)	$ (2,171)		$ 104

Restatement of Previously Iss_5

Restatement of Previously Issued Financial Statements - Schedule of Cash Flows (Details) - 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	Dec. 31, 2023
Cash flows from operating activities:
Net loss	$ (60,808)	$ (81,393)	$ (69,804)	$ (87,232)	$ (62,789)	$ 18,930	$ (212,003)	$ (131,091)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization							47,339	19,660
Stock-based compensation expense							9,669	16,013
Noncash research and development expense (finance lease)							0	22,223
Noncash operating lease expense							18,015	23,965
Gain from sale of priority review voucher	0			0			0	(92,930)
Change in excess inventory reserve							8,035	9,202
Other non-cash items							(14)	100
Gain on foreign currency exchange rates							(86)	(1,062)
Changes in operating assets and liabilities:
Accounts receivable							0	(14,600)
Prepaid expenses and other assets							(47,022)	2,117
Inventory							(38,038)	(26,197)
Operating right of use assets								0
Accounts payable							6,660	1,712
Accrued expenses and other liabilities							2,986	5,709
Accrued interest payable under finance lease							(8,010)	(3,203)
Operating lease liabilities							15,323	18,686
Deferred revenue							0	(248)
Net cash (used in) provided by operating activities							(209,856)	(180,910)
Cash flows from investing activities:
Purchase of property, plant and equipment							(2,114)	(2,975)
Proceeds from maturities of marketable securities							0	(43,297)
Proceeds from maturities of marketable securities							0	99,521
Proceeds from sales of marketable securities							0	5,853
Purchase of intangible assets							0	(868)
Proceeds from sale of priority review voucher							0	92,930
Net cash provided by investing activities							1,432	151,164
Cash flows from financing activities:
Proceeds from exercise of stock options and ESPP contributions							0	93
Principal payments on finance leases							(69,576)	(40,299)
Net cash provided by financing activities							52,479	89,670
Increase in cash, cash equivalents and restricted cash							(155,945)	59,924
Cash, cash equivalents and restricted cash at beginning of period			$ 274,597			158,445	274,597	158,445
Cash, cash equivalents and restricted cash at end of period	118,652			218,369			118,652	218,369
Reconciliation of cash, cash equivalents and restricted cash:
Cash and cash equivalents	70,651			165,347			70,651	165,347	$ 221,755
Restricted cash included in other current assets	4,360			8,885			4,360	8,885
Restricted cash included in restricted cash and other non-current assets	43,641			44,137			43,641	44,137
Total cash, cash equivalents and restricted cash	$ 118,652			218,369			118,652	218,369	$ 274,597
Supplemental cash flow disclosures from investing and financing activities:
Right-of-use assets obtained in exchange for operating lease liabilities							0	(708)
Purchases of property, plant and equipment included in accounts payable and accrued expenses							31	941
Offering expenses included in accounts payable and accrued expenses							0	248
Right-of-use assets obtained in exchange for finance lease liabilities							41,893	21,508
Increase (reduction) of right of use asset and associated operating lease liability due to lease reassessment								0
Cash paid during the period for income taxes								5
As Previously Reported
Cash flows from operating activities:
Net loss				(71,731)	(72,908)	21,240		(123,399)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization								3,124
Stock-based compensation expense								16,013
Noncash research and development expense (finance lease)								0
Noncash operating lease expense								0
Gain from sale of priority review voucher								(92,930)
Change in excess inventory reserve								5,333
Other non-cash items								19
Gain on foreign currency exchange rates								0
Changes in operating assets and liabilities:
Accounts receivable								(23,000)
Prepaid expenses and other assets								(523)
Inventory								(24,931)
Operating right of use assets								(40,101)
Accounts payable								(5,787)
Accrued expenses and other liabilities								7,125
Accrued interest payable under finance lease								0
Operating lease liabilities								30,506
Deferred revenue								8,152
Net cash (used in) provided by operating activities								(221,209)
Cash flows from investing activities:
Purchase of property, plant and equipment								(2,975)
Proceeds from maturities of marketable securities								(43,297)
Proceeds from maturities of marketable securities								99,521
Proceeds from sales of marketable securities								5,853
Purchase of intangible assets								(868)
Proceeds from sale of priority review voucher								92,930
Net cash provided by investing activities								151,164
Cash flows from financing activities:
Proceeds from exercise of stock options and ESPP contributions								93
Principal payments on finance leases								0
Net cash provided by financing activities								129,969
Increase in cash, cash equivalents and restricted cash								59,924
Cash, cash equivalents and restricted cash at beginning of period						158,445		158,445
Cash, cash equivalents and restricted cash at end of period				218,369				218,369
Reconciliation of cash, cash equivalents and restricted cash:
Cash and cash equivalents				165,347				165,347
Restricted cash included in other current assets				8,885				8,885
Restricted cash included in restricted cash and other non-current assets				44,137				44,137
Total cash, cash equivalents and restricted cash				218,369				218,369
Supplemental cash flow disclosures from investing and financing activities:
Right-of-use assets obtained in exchange for operating lease liabilities								44,819
Purchases of property, plant and equipment included in accounts payable and accrued expenses								941
Offering expenses included in accounts payable and accrued expenses								248
Right-of-use assets obtained in exchange for finance lease liabilities								0
Increase (reduction) of right of use asset and associated operating lease liability due to lease reassessment								8,003
Cash paid during the period for income taxes								5
Revision of Prior Period, Error Correction, Adjustment | Adjustments to Embedded Leases
Cash flows from operating activities:
Net loss				(17,139)	9,482	(2,351)		(10,008)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization								16,648
Stock-based compensation expense								0
Noncash research and development expense (finance lease)								22,223
Noncash operating lease expense								23,965
Gain from sale of priority review voucher								0
Change in excess inventory reserve								1,554
Other non-cash items								0
Gain on foreign currency exchange rates								(1,062)
Changes in operating assets and liabilities:
Accounts receivable								0
Prepaid expenses and other assets								2,640
Inventory								1,651
Operating right of use assets								40,101
Accounts payable								7,183
Accrued expenses and other liabilities								583
Accrued interest payable under finance lease								(3,203)
Operating lease liabilities								(11,820)
Deferred revenue								0
Net cash (used in) provided by operating activities								40,299
Cash flows from investing activities:
Purchase of property, plant and equipment								0
Proceeds from maturities of marketable securities								0
Proceeds from maturities of marketable securities								0
Proceeds from sales of marketable securities								0
Purchase of intangible assets								0
Proceeds from sale of priority review voucher								0
Net cash provided by investing activities								0
Cash flows from financing activities:
Proceeds from exercise of stock options and ESPP contributions								0
Principal payments on finance leases								(40,299)
Net cash provided by financing activities								(40,299)
Increase in cash, cash equivalents and restricted cash								0
Cash, cash equivalents and restricted cash at beginning of period						0		0
Cash, cash equivalents and restricted cash at end of period				0				0
Reconciliation of cash, cash equivalents and restricted cash:
Cash and cash equivalents				0				0
Restricted cash included in other current assets				0				0
Restricted cash included in restricted cash and other non-current assets				0				0
Total cash, cash equivalents and restricted cash				0				0
Supplemental cash flow disclosures from investing and financing activities:
Right-of-use assets obtained in exchange for operating lease liabilities								(45,527)
Purchases of property, plant and equipment included in accounts payable and accrued expenses								0
Offering expenses included in accounts payable and accrued expenses								0
Right-of-use assets obtained in exchange for finance lease liabilities								21,508
Increase (reduction) of right of use asset and associated operating lease liability due to lease reassessment								(8,003)
Cash paid during the period for income taxes								0
Revision of Prior Period, Error Correction, Adjustment | Other Adjustments
Cash flows from operating activities:
Net loss				1,638	$ 637	41		2,316
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization								(112)
Stock-based compensation expense								0
Noncash research and development expense (finance lease)								0
Noncash operating lease expense								0
Gain from sale of priority review voucher								0
Change in excess inventory reserve								2,315
Other non-cash items								81
Gain on foreign currency exchange rates								0
Changes in operating assets and liabilities:
Accounts receivable								8,400
Prepaid expenses and other assets								0
Inventory								(2,917)
Operating right of use assets								0
Accounts payable								316
Accrued expenses and other liabilities								(1,999)
Accrued interest payable under finance lease								0
Operating lease liabilities								0
Deferred revenue								(8,400)
Net cash (used in) provided by operating activities								0
Cash flows from investing activities:
Purchase of property, plant and equipment								0
Proceeds from maturities of marketable securities								0
Proceeds from maturities of marketable securities								0
Proceeds from sales of marketable securities								0
Purchase of intangible assets								0
Proceeds from sale of priority review voucher								0
Net cash provided by investing activities								0
Cash flows from financing activities:
Proceeds from exercise of stock options and ESPP contributions								0
Principal payments on finance leases								0
Net cash provided by financing activities								0
Increase in cash, cash equivalents and restricted cash								0
Cash, cash equivalents and restricted cash at beginning of period						$ 0		0
Cash, cash equivalents and restricted cash at end of period				0				0
Reconciliation of cash, cash equivalents and restricted cash:
Cash and cash equivalents				0				0
Restricted cash included in other current assets				0				0
Restricted cash included in restricted cash and other non-current assets				0				0
Total cash, cash equivalents and restricted cash				$ 0				0
Supplemental cash flow disclosures from investing and financing activities:
Right-of-use assets obtained in exchange for operating lease liabilities								0
Purchases of property, plant and equipment included in accounts payable and accrued expenses								0
Offering expenses included in accounts payable and accrued expenses								0
Right-of-use assets obtained in exchange for finance lease liabilities								0
Increase (reduction) of right of use asset and associated operating lease liability due to lease reassessment								0
Cash paid during the period for income taxes								0
Private Placement
Cash flows from financing activities:
Proceeds from issuance of common stock							0	(196)
Private Placement | As Previously Reported
Cash flows from financing activities:
Proceeds from issuance of common stock								(196)
Private Placement | Revision of Prior Period, Error Correction, Adjustment | Adjustments to Embedded Leases
Cash flows from financing activities:
Proceeds from issuance of common stock								0
Private Placement | Revision of Prior Period, Error Correction, Adjustment | Other Adjustments
Cash flows from financing activities:
Proceeds from issuance of common stock								0
Public Offering
Cash flows from financing activities:
Proceeds from issuance of common stock							$ 0	130,072
Public Offering | As Previously Reported
Cash flows from financing activities:
Proceeds from issuance of common stock								130,072
Public Offering | Revision of Prior Period, Error Correction, Adjustment | Adjustments to Embedded Leases
Cash flows from financing activities:
Proceeds from issuance of common stock								0
Public Offering | Revision of Prior Period, Error Correction, Adjustment | Other Adjustments
Cash flows from financing activities:
Proceeds from issuance of common stock								$ 0

Subsequent events (Details)

Subsequent events (Details) - 2023 Incentive Award Plan - Subsequent Event	Nov. 06, 2024 shares
Subsequent Event [Line Items]
Increase in number of shares authorized for issuance (in shares)	15,000,000
Common shares reserved for issuance (in shares)	20,200,000