Krystal Biotech (KRYS) 10-Q 7 Nov 22 2022 Q3 Quarterly report Financial data

Cover

Cover - shares	9 Months Ended
	Sep. 30, 2022	Oct. 31, 2022
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2022
Document Transition Report	false
Entity File Number	001-38210
Entity Registrant Name	Krystal Biotech, Inc.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	82-1080209
Entity Address, Address Line One	2100 Wharton Street
Entity Address, Address Line Two	Suite 701
Entity Address, City or Town	Pittsburgh
Entity Address, State or Province	PA
Entity Address, Postal Zip Code	15203
City Area Code	412
Local Phone Number	586-5830
Title of 12(b) Security	Common Stock
Trading Symbol	KRYS
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		25,747,647
Amendment Flag	false
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	Q3
Entity Central Index Key	0001711279
Current Fiscal Year End Date	--12-31

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets (unaudited) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Current assets
Cash and cash equivalents	$ 186,409	$ 341,246
Short-term investments	208,011	96,850
Prepaid expenses and other current assets	3,158	4,171
Total current assets	397,578	442,267
Property and equipment, net	157,786	112,355
Long-term investments	12,557	64,371
Right-of-use assets	8,253	7,228
Other non-current assets	205	74
Total assets	576,379	626,295
Current liabilities
Accounts payable	5,761	8,398
Current portion of lease liability	1,547	1,041
Accrued expenses and other current liabilities	20,724	16,297
Total current liabilities	28,032	25,736
Lease liability	7,575	6,983
Total liabilities	35,607	32,719
Commitments and contingencies (Note 6)
Stockholders' equity
Preferred stock; $0.00001 par value; 20,000,000 shares authorized at    September 30, 2022 and December 31, 2021; 2,061,773    shares issued, and no shares outstanding at September 30, 2022    and December 31, 2021	0	0
Common stock; $0.00001 par value; 80,000,000 shares authorized a September 30, 2022 and December 31, 2021; 25,709,664 shares issued and outstanding at September 30, 2022; and 25,207,985 shares issued and outstanding at December 31, 2021	0	0
Additional paid-in capital	790,954	734,523
Accumulated other comprehensive loss	(1,475)	(163)
Accumulated deficit	(248,707)	(140,784)
Total stockholders' equity	540,772	593,576
Total liabilities and stockholders' equity	$ 576,379	$ 626,295

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (unaudited) (Parenthetical) - $ / shares	Sep. 30, 2022	Dec. 31, 2021
Statement of Financial Position [Abstract]
Preferred stock, par value (in dollars per share)	$ 0.00001	$ 0.00001
Preferred stock, shares authorized	20,000,000	20,000,000
Preferred stock, shares issued	2,061,773	2,061,773
Preferred stock, shares outstanding	0	0
Common stock, par value (in dollars per share)	$ 0.00001	$ 0.00001
Common stock, shares authorized	80,000,000	80,000,000
Common stock, shares issued	25,709,664	25,207,985
Common stock, shares outstanding	25,709,664	25,207,985

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations and Comprehensive Loss (unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Expenses
Research and development	$ 11,516	$ 6,080	$ 31,720	$ 18,875
General and administrative	19,935	9,572	53,705	27,524
Litigation settlement	0	0	25,000	0
Total operating expenses	31,451	15,652	110,425	46,399
Loss from operations	(31,451)	(15,652)	(110,425)	(46,399)
Other Income (Expense)
Interest and other income, net	1,601	63	2,502	127
Interest expense	0	0	0	(1,492)
Net loss	(29,850)	(15,589)	(107,923)	(47,764)
Unrealized gain (loss) on available-for-sale securities and currency translation adjustment	70	7	(1,312)	(20)
Comprehensive loss	$ (29,780)	$ (15,582)	$ (109,235)	$ (47,784)
Net loss per common share: basic (in dollars per share)	$ (1.17)	$ (0.70)	$ (4.24)	$ (2.18)
Net loss per common share: diluted (in dollars per share)	$ (1.17)	$ (0.70)	$ (4.24)	$ (2.18)
Weighted-average common shares outstanding: basic	25,619,125	22,212,266	25,428,097	21,893,656
Weighted-average common shares outstanding: diluted	25,619,125	22,212,266	25,428,097	21,893,656

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Stockholders' Equity (unaudited) - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Loss	Accumulated Deficit
Beginning balance (in shares) at Dec. 31, 2020		19,714,220
Beginning balance at Dec. 31, 2020	$ 292,084	$ 0	$ 363,292	$ 6	$ (71,214)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock, net, (in shares)		2,489,837
Issuance of common stock, net	152,033		152,033
Stock-based compensation expense	2,350		2,350
Unrealized gain (loss) on investments and other	(3)			(3)
Net loss	(15,812)				(15,812)
Ending balance (in shares) at Mar. 31, 2021		22,204,057
Ending balance at Mar. 31, 2021	430,652	$ 0	517,675	3	(87,026)
Beginning balance (in shares) at Dec. 31, 2020		19,714,220
Beginning balance at Dec. 31, 2020	292,084	$ 0	363,292	6	(71,214)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Unrealized gain (loss) on investments and other	(20)
Net loss	(47,764)
Ending balance (in shares) at Sep. 30, 2021		22,237,984
Ending balance at Sep. 30, 2021	408,237	$ 0	527,229	(14)	(118,978)
Beginning balance (in shares) at Mar. 31, 2021		22,204,057
Beginning balance at Mar. 31, 2021	430,652	$ 0	517,675	3	(87,026)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock, net, (in shares)		975
Issuance of common stock, net	14		14
Stock-based compensation expense	4,261		4,261
Unrealized gain (loss) on investments and other	(24)			(24)
Net loss	(16,363)				(16,363)
Ending balance (in shares) at Jun. 30, 2021		22,205,032
Ending balance at Jun. 30, 2021	418,540	$ 0	521,950	(21)	(103,389)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock, net, (in shares)		32,952
Issuance of common stock, net	1,534		1,534
Stock-based compensation expense	3,745		3,745
Unrealized gain (loss) on investments and other	7			7
Net loss	(15,589)				(15,589)
Ending balance (in shares) at Sep. 30, 2021		22,237,984
Ending balance at Sep. 30, 2021	408,237	$ 0	527,229	(14)	(118,978)
Beginning balance (in shares) at Dec. 31, 2021		25,207,985
Beginning balance at Dec. 31, 2021	593,576	$ 0	734,523	(163)	(140,784)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock, net, (in shares)		1,475
Issuance of common stock, net	55		55
Shares surrendered for taxes and forfeitures (in shares)		(10,379)
Shares surrendered for taxes and forfeitures	(649)		(649)
Stock-based compensation expense	6,571		6,571
Unrealized gain (loss) on investments and other	(1,034)			(1,034)
Net loss	(49,965)				(49,965)
Ending balance (in shares) at Mar. 31, 2022		25,199,081
Ending balance at Mar. 31, 2022	548,554	$ 0	740,500	(1,197)	(190,749)
Beginning balance (in shares) at Dec. 31, 2021		25,207,985
Beginning balance at Dec. 31, 2021	593,576	$ 0	734,523	(163)	(140,784)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Unrealized gain (loss) on investments and other	(1,312)
Net loss	(107,923)
Ending balance (in shares) at Sep. 30, 2022		25,709,664
Ending balance at Sep. 30, 2022	540,772	$ 0	790,954	(1,475)	(248,707)
Beginning balance (in shares) at Mar. 31, 2022		25,199,081
Beginning balance at Mar. 31, 2022	548,554	$ 0	740,500	(1,197)	(190,749)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock, net, (in shares)		472,706
Issuance of common stock, net	$ 30,748		30,748
Shares surrendered for taxes and forfeitures (in shares)	(7,500)
Stock-based compensation expense	$ 8,335		8,335
Unrealized gain (loss) on investments and other	(348)			(348)
Net loss	(28,108)				(28,108)
Ending balance (in shares) at Jun. 30, 2022		25,664,287
Ending balance at Jun. 30, 2022	559,181	$ 0	779,583	(1,545)	(218,857)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock, net, (in shares)		45,377
Issuance of common stock, net	2,176		2,176
Stock-based compensation expense	9,195		9,195
Unrealized gain (loss) on investments and other	70			70
Net loss	(29,850)				(29,850)
Ending balance (in shares) at Sep. 30, 2022		25,709,664
Ending balance at Sep. 30, 2022	$ 540,772	$ 0	$ 790,954	$ (1,475)	$ (248,707)

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Cash Flows (unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021
Operating Activities
Net loss	$ (107,923)	$ (47,764)
Adjustments to reconcile net loss to net cash used in operating activities
Depreciation and amortization	2,966	1,985
Stock-based compensation expense	23,678	10,174
Loss on disposals of fixed assets	22	0
Non-cash interest expense	0	1,492
Other, net	(224)	(224)
Changes in operating assets and liabilities
Prepaid expenses and other current assets	1,031	1,038
Other non-current assets	(31)	0
Lease liability	(459)	(240)
Accounts payable	(316)	(225)
Accrued expenses and other current liabilities	3,016	6,726
Net cash used in operating activities	(78,240)	(27,038)
Investing Activities
Purchases of property and equipment	(47,762)	(27,453)
Purchases of investments	(214,712)	(83,810)
Proceeds from maturities of investments	153,599	11,033
Net cash used in investing activities	(108,875)	(100,230)
Financing Activities
Issuance of common stock, net	32,927	153,573
Taxes paid related to settlement of restricted stock awards	(649)	0
Repayment of ASTRA build to suit liability	0	(7,960)
Net cash provided by financing activities	32,278	145,613
Net (decrease) increase in cash and cash equivalents	(154,837)	18,345
Cash and cash equivalents at beginning of period	341,246	268,269
Cash and cash equivalents at end of period	186,409	286,614
Supplemental Disclosures of Non-Cash Investing and Financing Activities
Unpaid purchases of property and equipment included in accounts payable and accrued expenses	15,305	23,213
Initial recognition of right-of-use assets	$ 1,556	$ 4,396

Organization

Organization	9 Months Ended
	Sep. 30, 2022
Accounting Policies [Abstract]
Organization	Organization Krystal Biotech, Inc. (the “Company,” or “we” or other similar pronouns) commenced operations on April 15, 2016. On March 31, 2017, the Company converted from a California limited liability company to a Delaware C-corporation, and changed its name from Krystal Biotech LLC to Krystal Biotech, Inc. On June 19, 2018, the Company incorporated Krystal Australia Pty Ltd., an Australian proprietary limited company, a wholly-owned subsidiary, for the purpose of undertaking preclinical and clinical studies in Australia. On April 23, 2019, the Company incorporated Jeune Aesthetics, Inc., formerly known as Jeune, Inc. ("Jeune"), in Delaware, a wholly-owned subsidiary, for the purpose of undertaking preclinical and clinical studies for aesthetic skin conditions. On January 7, 2022 and August 25, 2022, the Company incorporated Krystal Biotech Switzerland GmbH and Krystal Biotech Netherlands, B.V., respectively, for the purpose of establishing initial operations in Europe for the development and commercialization of Krystal's pipeline. We are a biotechnology company focused on developing and commercializing genetic medicines for patients with rare diseases. Using our patented platform that is based on engineered HSV-1, we create vectors that efficiently deliver therapeutic transgenes to cells of interest in multiple organ systems. The cell’s own machinery then transcribes and translates the encoded effector to treat or prevent disease. We formulate our vectors for non-invasive or minimally invasive routes of administration at a healthcare professional’s office or potentially in the patient’s home by a healthcare professional. Our goal is to develop easy-to-use medicines to dramatically improve the lives of patients living with rare diseases and chronic conditions. Our innovative technology platform is supported by in-house, commercial scale current good manufacturing practices ("cGMP") manufacturing capabilities. Liquidity As of September 30, 2022, the Company had an accumulated deficit of $248.7 million. With the net proceeds raised from its public offerings, the Company believes that its cash, cash equivalents and short-term investments of approximately $394.4 million as of September 30, 2022 will be sufficient to allow the Company to fund its planned operations for at least the next 12 months from the date of this Quarterly Report on Form 10-Q. As the Company continues to incur losses, a transition to profitability is dependent upon the successful development, approval and commercialization of its product candidates and the achievement of a level of revenues adequate to support the Company’s cost structure. The Company may never achieve profitability and unless and until it does, the Company will continue to need to raise additional capital or obtain financing from other sources. Management intends to fund future operations through the sale of equity and debt financings and may also seek additional capital through arrangements with strategic partners or other sources. There can be no assurance that additional funding will be available on terms acceptable to the Company, if at all. The Company is subject to risks common to companies in the biotechnology industry, including but not limited to the failure of product candidates in clinical and preclinical studies, the development of competing product candidates or other technological innovations by competitors, dependence on key personnel, protection of proprietary technology, compliance with government regulations and the ability to c ommercialize product candidates.

Summary of Significant Accounti

Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2022
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies Basis of Presentation The accompanying interim condensed consolidated financial statements have been prepared in conformity with generally accepted accounting principles in the United States of America (“GAAP”). In the opinion of management, all adjustments, which consist of all normal recurring adjustments necessary for a fair presentation of the Company's financial position and results of operations for the interim periods presented, are reflected in the interim condensed consolidated financial statements. All intercompany balances and transactions have been eliminated in consolidation. Certain prior period amounts have been reclassified to conform to the current period presentation. The reclassified amounts have no impact on the Company’s previously reported financial position or results of operation. 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 unaudited interim condensed consolidated financial statements should be read in conjunction with the Company’s audited consolidated financial statements and the notes thereto included in the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2021, as filed with the SEC on February 28, 2022. Risks and Uncertainties The coronavirus ("COVID-19") pandemic has resulted, and is likely to continue to result, in significant national and global economic uncertainty and may adversely affect the Company's business. The Company is continuing to actively monitor the impact of the COVID-19 pandemic and the related effects on its financial condition, liquidity, operations, suppliers, industry, and workforce. The full extent, consequences, and duration of the COVID-19 pandemic and the resulting impact on the Company cannot currently be predicted. The Company will continue to evaluate the impact that the pandemic could have on the operations, financial position, and the results of operations and cash flows during fiscal year 2022. 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 condensed consolidated 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 are used in the following areas including stock-based compensation expense, accrued expenses, the fair value of financial instruments, the incremental borrowing rate for lease liabilities, and the valuation allowance included in the deferred income tax calculation. Segment and Geographical Information Operating segments are defined as components of an enterprise about which separate discrete information is available for evaluation by the chief operating decision maker, or decision-making group, in deciding how to allocate resources and in assessing performance. The Company and the Company’s chief operating decision maker view the Company’s operations and manage its business in one operating segment, which is the business of developing and commercializing pharmaceutical products. Concentrations of Credit Risk and Off-Balance Sheet Risk Financial instruments that potentially subject the Company to credit risk consist of cash, cash equivalents and investments. The Company’s policy is to invest its cash, cash equivalents and investments in money market funds, corporate bonds, commercial paper, government agency securities and various other bank deposit accounts. The counterparties to the agreements relating to the Company’s investments consist of financial institutions of high credit standing. The Company is exposed to credit risk in the event of default by the financial institutions to the extent amounts recorded on the condensed consolidated balance sheets are in excess of insured limits. The Company has not experienced any credit losses in such accounts and does not believe it is exposed to any significant credit risk on these funds. The Company has no financial instruments with off-balance sheet risk of loss. Cash, Cash Equivalents and Investments Cash and cash equivalents consist of money market funds and bank deposits. Cash equivalents are defined as short-term, highly liquid investments with original maturities of 90 days or less at the date of purchase. Investments with maturities of less than one year are classified as short-term investments on the condensed consolidated balance sheets and consist of commercial paper, corporate bonds, and government agency securities. Investments with maturities of greater than one year are classified as long-term investments on the condensed consolidated balance sheets and consist of corporate bonds and government agency securities. Accrued interest on corporate bonds and government agency securities are also classified as short-term investments. As our entire investment portfolio is considered available for use in current operations, we classify all investments as available-for-sale securities. Available-for-sale securities are carried at fair value, with unrealized gains and losses reported in accumulated other comprehensive loss, which is a separate component of stockholders’ equity in the condensed consolidated balance sheets. Fair Value of Financial Instruments Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. There is a three-level hierarchy that prioritizes the inputs used in determining fair value by their reliability and preferred use, as follows: • Level 1 — Valuations based on quoted prices in active markets for identical assets or liabilities. • Level 2 — Valuations based on quoted prices in active markets for similar assets and liabilities, quoted prices for identical or similar assets or liabilities in inactive markets, or other inputs that are observable or can be corroborated by observable market data. • Level 3 — Valuations based on inputs that are both significant to the fair value measurement and unobservable. To the extent that a valuation is based on models or inputs that are less observable, or unobservable in the market, the determination of fair value requires more judgment. Accordingly, the degree of judgment exercised by the Company in determining fair value is greatest for instruments categorized within Level 3. A financial instrument’s level within the fair value hierarchy is based on the lowest level of any input that is significant to the fair value measurement. There have been no significant changes to the valuation methods utilized by the Company during the periods presented. There have been no transfers between Level 1, Level 2, and Level 3 in any periods presented. The carrying amounts of financial instruments consisting of cash and cash equivalents, investments, prepaid expenses and other current assets, accounts payable, accrued expenses and other current liabilities included in the Company’s condensed consolidated financial statements, are reasonable estimates of fair value, primarily due to their short maturities. Our available-for-sale, short-term and long-term investments, which consist of commercial paper, corporate bonds, and U.S. government agency securities are considered to be Level 2 valuations. The fair value of Level 2 financial assets is determined using inputs that are observable in the market or can be derived principally from or corroborated by observable market data, such as pricing for similar securities, recently executed transactions, cash flow models with yield curves, and benchmark securities. In addition, Level 2 financial instruments are valued using comparisons to like-kind financial instruments and models that use readily observable market data as their basis. Property and Equipment, net Property and equipment, net, is stated at cost, less accumulated depreciation. Maintenance and repairs that do not improve or extend the lives of the respective assets are expensed to operations as incurred, while costs of major additions and betterments are capitalized. Upon disposal, the related cost and accumulated depreciation is removed from the accounts and any resulting gain or loss is included in the results of operations. Depreciation is recorded using the straight-line method over the estimated useful lives of the respective assets, which are as follows: Computer equipment and software 3 - 7 years Laboratory and manufacturing equipment 3 - 20 years Furniture and fixtures 3 - 7 years Leasehold improvement lesser of remaining useful life or remaining lease term The Company reviews the estimated useful lives of its property and equipment on a continuing basis. In evaluating the useful lives, the Company considers how long assets will remain functionally effective, whether the technology continues to be relevant and considers other competitive and economic factors. If the assessment indicates that the assets will be used for a shorter or longer period than previously anticipated, the useful life of the assets is adjusted, resulting in a change in estimate. Changes in estimates are accounted for on a prospective basis by depreciating the current carrying values of the assets over their revised remaining useful lives. The review performed by the Company in the current year indicated that certain pieces of lab equipment would be functional for a longer term than previously estimated and as a result, the Company increased the useful lives of these assets from 7 to 15 years. This change was effective and accounted for prospectively beginning in Q3 2022. The effect of this change in useful life estimate did not result in a material change to depreciation expense. Construction in progress ("CIP") is not depreciated until the asset is placed in service. Impairment of Long-Lived Assets The Company evaluates long-lived assets for potential impairment when events or changes in circumstances indicate the carrying value of the assets may not be recoverable. An impairment loss would be recognized when estimated future cash flows expected to result from the use of the asset and its eventual disposition are less than the carrying amount of the asset. The Company has not recognized any impairment losses for the three and nine months ended September 30, 2022 and 2021, respectively. Leases The Company accounts for its lease agreements in accordance with FASB ASC Topic 842, Leases . Right-of-use lease assets represent the right to use an underlying asset during the lease term and the lease obligations represent the commitment to make lease payments arising from the lease. Right-of-use lease assets and obligations are recognized based on the present value of remaining lease payments over the lease term. As the Company’s existing lease agreements do not provide an implicit rate and as the Company does not have any external borrowings, the Company has used an estimated incremental borrowing rate based on the information available at lease commencement in determining the present value of lease payments. Operating lease expense is recognized on a straight-line basis over the lease term. Variable lease expense is recognized in the period in which the obligation for the payment is incurred. In addition, the Company also has made an accounting policy election to exclude leases with an initial term of twelve months or less from its balance sheet and to account for lease and non-lease components of its operating leases as a single component. For lease arrangements where it has been determined that the Company has control over an asset that is under construction and is thus considered the accounting owner of the asset during the construction period, the Company records a construction in progress asset and corresponding financial obligation on the condensed consolidated balance sheet. Once the construction is complete, an assessment is performed to determine whether the lease meets certain sale-leaseback criteria. If the sale-leaseback criteria are determined to be met, the Company will remove the asset and related financial obligation from the condensed consolidated balance sheet and treat the lease as either an operating or finance lease based on an assessment of the guidance. If, upon completion of construction, the project does not meet the "sale-leaseback" criteria, the lease will be treated as a financing obligation and the Company will depreciate the asset over its estimated useful life for financial reporting purposes once the asset has been placed into service. Research and Development Expenses Research and development costs are charged to expense as incurred in performing research and development activities. These costs include employee compensation costs, facilities and overhead, preclinical and clinical activities, clinical manufacturing costs, contract management services, regulatory and other related costs. The Company estimates contract research and clinical trials materials manufacturing expenses based on the services performed pursuant to contracts with research organizations and manufacturing organizations that manufacture materials used in the Company’s ongoing preclinical and clinical studies. Non-refundable advanced payments for goods or services to be received in the future for use in research and development activities are deferred and capitalized. The capitalized amounts are expensed as the related goods are delivered or the services are performed. In accruing service fees, the Company estimates the time period over which services will be performed and the level of effort to be expended in each period. These estimates are based on communications with the third-party service providers and the Company’s estimates of accrued expenses using information available at each balance sheet date. If the actual timing of the performance of services or the level of effort varies from the estimate, the Company will adjust the accrual accordingly. Stock-Based Compensation Expense The Company applies the fair value recognition provisions of Financial Accounting Standards Board ("FASB") Accounting Standards Codification, or ASC, Topic 718, Compensation—Stock Compensation ("ASC 718"), to account for stock-based compensation. Compensation costs related to stock options granted are based on the estimated fair value of the awards on the date of grant. ASC 718 requires all stock-based payments, including grants of stock options and restricted stock, to be recognized in the consolidated statements of operations based on their grant-date fair values. Compensation expense is recognized on a straight-line basis based on the grant-date fair value over the associated service period of the award, which is generally the vesting term. The Company estimates the fair value of its stock options using the Black-Scholes option pricing model, which requires the input of subjective assumptions, including: (i) the expected stock price volatility; (ii) the expected term of the award; (iii) the risk-free interest rate; and (iv) expected dividends. Once the Company's own sufficient historical volatility data was obtained, the Company eliminated the use of a representative peer group and began using only its own historical volatility data in its estimate of expected volatility. The Company estimates the expected term of its stock options using the “simplified” method, whereby the expected term equals the arithmetic mean of the vesting term and the original contractual term of the option. The risk-free interest rates are based on US Treasury securities with a maturity date commensurate with the expected term of the associated award. The Company has never paid and does not expect to pay dividends in the foreseeable future. The Company accounts for forfeitures as they occur. Stock-based compensation expense recognized in the financial statements is based on awards for which service conditions are expected to be satisfied. Comprehensive Loss Comprehensive loss is defined as the change in equity during a period from transactions from non-owner sources. Unrealized gains or losses on available-for-sale securities is a component of other comprehensive gains or losses. We have not recorded any reclassifications from other comprehensive gains or losses to net loss during any period presented. Recent Accounting Pronouncements From time to time, new accounting pronouncements are issued by the FASB or other accounting standard setting bodies that the Company adopts as of the specified effective date. The Company does not believe that the adoption of recently issued standards have or may have a material impact on the condensed consolidated statements or disclosures.

Net Loss Per Share Attributable

Net Loss Per Share Attributable to Common Stockholders	9 Months Ended
	Sep. 30, 2022
Earnings Per Share [Abstract]
Net Loss Per Share Attributable to Common Stockholders	Net Loss Per Share Attributable to Common Stockholders Basic net loss per share attributable to common stockholders is calculated by dividing net loss attributable to common stockholders by the weighted average shares outstanding during the period, without consideration for common stock equivalents. Diluted net loss per share attributable to common stockholders is computed by dividing the net loss by the weighted-average number of shares of common stock and common share equivalents outstanding for the period. Common share equivalents consist of common stock issuable upon exercise of stock options and vesting of restricted stock awards. There were 3,565,110 and 1,900,638 common share equivalents outstanding as of September 30, 2022 and 2021, respectively, in the form of stock options and unvested restricted stock awards, that have been excluded from the calculation of diluted net loss per common share as their effect would be anti-dilutive for all periods presented. Three Months Ended Nine Months Ended (In thousands, except share and per share data) 2022 2021 2022 2021 Numerator: Net loss $ (29,850) $ (15,589) $ (107,923) $ (47,764) Denominator: Weighted-average basic and diluted common shares 25,619,125 22,212,266 25,428,097 21,893,656 Basic and diluted net loss per $ (1.17) $ (0.70) $ (4.24) $ (2.18)

Fair Value Instruments

Fair Value Instruments	9 Months Ended
	Sep. 30, 2022
Fair Value Disclosures [Abstract]
Fair Value Instruments	Fair Value Instruments The following tables show the Company’s cash, cash equivalents and available-for-sale securities by significant investment category as of September 30, 2022 and December 31, 2021, respectively (in thousands): September 30, 2022 Amortized Cost Gross Gross Aggregate Fair Cash and Cash Short-term Marketable Securities (1) Long-term Marketable Securities (2) Level 1: Cash and cash equivalents $ 186,409 $ — $ — $ 186,409 $ 186,409 $ — $ — Subtotal 186,409 — — 186,409 186,409 — — Level 2: Commercial paper 52,777 2 (41) 52,738 — 52,738 — Corporate bonds 94,415 — (886) 93,529 — 87,291 6,238 U.S. government agency securities 74,824 36 (559) 74,301 — 67,982 6,319 Subtotal 222,016 38 (1,486) 220,568 — 208,011 12,557 Total $ 408,425 $ 38 $ (1,486) $ 406,977 $ 186,409 $ 208,011 $ 12,557 December 31, 2021 Amortized Cost Gross Gross Aggregate Fair Cash and Cash Short-term Marketable Securities (1) Long-term Marketable Securities (2) Level 1: Cash and cash equivalents $ 341,246 $ — $ — $ 341,246 $ 341,246 $ — $ — Subtotal 341,246 — — 341,246 341,246 — — Level 2: Commercial paper 40,469 1 (4) 40,466 — 40,466 — Corporate bonds 83,300 10 (114) 83,196 — 35,768 47,428 U.S. government agency securities 37,621 — (62) 37,559 — 20,616 16,943 Subtotal 161,390 11 (180) 161,221 — 96,850 64,371 Total $ 502,636 $ 11 $ (180) $ 502,467 $ 341,246 $ 96,850 $ 64,371 (1) The Company’s short-term marketable securities mature in one year or less. (2) The Company's long-term marketable securities mature between one year and two years. See Note 2 to these unaudited condensed consolidated financial statements for additional discussion regarding the Company’s fair value measurements.

Balance Sheet Components

Balance Sheet Components	9 Months Ended
	Sep. 30, 2022
Balance Sheet Related Disclosures [Abstract]
Balance Sheet Components	Balance Sheet Components Property and Equipment, Net Property and equipment, net consist of the following (in thousands): September 30, December 31, Construction in progress $ 130,071 $ 104,340 Leasehold improvements 21,503 5,723 Furniture and fixtures 949 891 Computer equipment and software 96 85 Laboratory and manufacturing equipment 10,968 5,530 Total property and equipment 163,587 116,569 Accumulated depreciation (5,801) (4,214) Property and equipment, net $ 157,786 $ 112,355 Depreciation expense was $669 thousand and $1.6 million for the three and nine months ended September 30, 2022 and $474 thousand and $1.4 million for the three and nine months ended September 30, 2021, respectively. Accrued Expenses and Other Current Liabilities Accrued expenses and other current liabilities consisted of the following (in thousands): September 30, December 31, Accrued construction in progress $ 10,905 $ 9,606 Accrued professional fees 2,960 2,011 Accrued payroll and benefits 3,934 2,882 Accrued preclinical and clinical expenses 2,325 1,602 Accrued financing costs 10 26 Accrued taxes 122 83 Other current liabilities 468 87 Total $ 20,724 $ 16,297

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2022
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Significant Contracts and Agreements Lease Agreements On May 26, 2016, the Company signed an operating lease for laboratory and office space that commenced in June 2016 and was scheduled to expire on October 31, 2017 (the “2016 Lease”). The 2016 Lease has been amended several times to increase the area leased, which currently consists of approximately 47,000 square feet and includes the commercial scale cGMP-compliant manufacturing facility, ANCORIS. As a result of the lease amendments, the 2016 Lease expiration date was extended to October 31, 2031. On September 30, 2022, the Company amended the 2016 Lease ("Short-Term Amendment") to add a short-term lease for additional office space that commenced on October 1, 2022 and expires on September 30, 2023. The amendment increased the area leased by approximately 7,000 square feet through September 30, 2023, resulting in a total area leased of approximately 54,000 square feet. On December 26, 2019, the Company entered into a lease agreement for a second commercial gene therapy facility ("ASTRA") in the Pittsburgh, Pennsylvania area ("ASTRA lease") with Northfield I, LLC (the "Landlord", "Northfield", or "Lessor") with an initial lease term that expired on October 31, 2035. The ASTRA lease contained an option ("Purchase Option") to purchase the building, related improvements and take corresponding assignment of the Landlord's rights under its existing Ground Lease (the "Ground Lease"). On October 5, 2020, the Company was provided with notice that the initial delivery conditions of the building had been met, including completion of the building shell, interior slab, and exterior doors, and on October 15, 2020, the Company gave the Landlord notice of its intent to purchase ASTRA for approximately $9.4 million, subject to the parties entering into a commercially reasonable purchase and sale agreement. As a result of the Company's ability to exercise its option to purchase ASTRA, the Company obtained control over the construction in progress of ASTRA as of October 5, 2020. The Company recorded a $10.0 million CIP asset and a corresponding build to suit lease liability related to the costs incurred by the Landlord, offset by the previous cash contributions of $2.4 million. On January 29, 2021, the Company entered into a Purchase and Sale Agreement ("PSA") for ASTRA with Northfield related to the purchase option exercised by the Company on October 15, 2020, for a purchase price of $9.4 million. The Company held approximately $1.5 million on deposit with Northfield under the existing lease agreement and applied this deposit as a credit against the purchase price at closing. On February 1, 2021, Northfield delivered the space as substantially complete and made the space available for access by the Company, thus triggering lease commencement. As a result, the Company concluded that this transaction did not qualify for sale-leaseback accounting because it did not meet the definition of a sale. As control did not transfer to the Lessor at lease commencement, the transaction continued to be accounted for as construction in progress and a financing obligation. On March 5, 2021, the purchase closed and the Company determined that reclassification of the construction in progress to buildings and leasehold improvements was not appropriate as the interior of the building was not yet ready for its intended use. The building continues to be held under construction in progress as of September 30, 2022. The interior of the building is currently under construction and is expected to be completed in 1H 2023. From construction completion to the closing of the purchase, the Company recognized interest expense to accrete the financial obligation to a balance that equaled the cash consideration that was paid upon the close of purchase. For more information about the expected construction costs associated with ASTRA, see "ASTRA Contractual Obligations" below. As part of the transaction, the Company also became the accounting owner of the Ground Lease, due to obtaining control over ASTRA, and recorded the applicable operating right-of-use asset and corresponding lease liability as of October 5, 2020. When the PSA was finalized, the Company took assignment of the Lessor's Ground Lease, in accordance with the Purchase Option, of which lease payments are based on annual payments of $82 thousand, and are subject to a cumulative 10% escalation clause every 5 years through 2071. On December 15, 2021, the Company entered into a 3 year lease agreement for the Boston, Massachusetts office that commenced in January 2022 and expires in January 2025. On May 16, 2022, the Company entered into a 16 month lease agreement for the Zug, Switzerland office that commenced on September 1, 2022 and expires December 31, 2023. As of September 30, 2022, future minimum commitments under the Company’s operating leases with lease terms in excess of 12 months were as follows (in thousands): Operating 2022 (remaining three months) $ 404 2023 1,640 2024 1,539 2025 1,277 2026 1,277 Thereafter 12,062 Future minimum operating lease payments $ 18,199 Less: Interest 9,077 Present value of lease liability $ 9,122 Due to the Short-Term Amendment not exceeding twelve months, the Company has not recorded a right-of-use asset or corresponding lease liability for the amendment as of September 30, 2022. Future minimum remaining operating lease payments under this amendment are $40 thousand and $121 thousand for the years ending December 31, 2022 and 2023, respectively. Supplemental condensed consolidated balance sheet information related to leases is as follows: September 30, 2022 December 31, 2021 Operating leases: Right-of-use assets $ 8,253 $ 7,228 Current portion of lease liability 1,547 1,041 Lease liability 7,575 6,983 Total lease liability $ 9,122 $ 8,024 Weighted average remaining lease term, in years 12.6 14.4 Weighted average discount rate 9.4 % 9.5 % The components of the Company's lease expense are as follows: Three Months Ended Nine Months Ended 2022 2021 2022 2021 Lease cost: Operating lease expense $ 399 $ 339 $ 1,200 $ 836 Variable lease expense 48 65 168 183 Total lease expense $ 447 $ 404 $ 1,368 $ 1,019 Agreements with Contract Manufacturing Organizations and Contract Research Organizations The Company enters into various agreements in the normal course of business with Contract Research Organizations ("CROs"), Contract Manufacturing Organizations ("CMOs") and other third parties for preclinical research studies, clinical trials and testing and manufacturing services. The agreements with CMOs relate to the manufacturing of sterile gel that is mixed with in-house produced vectors as part of the final drug product applied in certain of our clinical trials. These agreements may also include research and development activities, storage, packaging, labeling, and/or testing of our preclinical and clinical-stage products. The Company is obligated to make milestone payments under certain of these agreements. The estimated remaining commitment as of September 30, 2022 under these agreements is approximately $2.4 million. The Company may also be responsible for the payment of a monthly service fee for project management services for the duration of any agreements. The Company has incurred expenses under these agreements of $2.1 million and $5.1 million for each of the three and nine months ended September 30, 2022 and $744 thousand and $3.3 million for the three and nine months ended September 30, 2021. Commercial Preparedness Activities The Company has contracted with various third parties to facilitate, coordinate and perform agreed upon commercial preparedness and market research activities relating to our lead product candidate. These contracts typically call for the payment of fees for services upon the achievement of certain milestones. The estimated remaining commitment as of September 30, 2022 is $6.2 million. The Company has incurred expenses under these activities of $3.2 million and $9.5 million for the three and nine months ended September 30, 2022 and $1.8 million and $4.1 million for the three and nine months ended September 30, 2021. ASTRA Contractual Obligations The Company has contracted with various third parties to complete the interior build-out of our second cGMP facility, ASTRA. Additionally, the Company has entered into various non-cancellable purchase agreements for long-lead materials to help avoid potential schedule disruptions or material shortages. These contracts typically call for the payment of fees for services or materials upon the achievement of certain milestones. The estimated remaining commitment as of September 30, 2022 is $10.3 million. The Company has included costs incurred to-date associated with ASTRA within construction in progress as of September 30, 2022. On June 30, 2021, the Company entered into a Standard Form of Contract for Construction and the corresponding General Conditions of the Contract for Construction (collectively, the “Agreement”) with The Whiting-Turner Contracting Company (“Whiting-Turner”), pursuant to which Whiting-Turner is constructing and managing the interior construction of ASTRA. Subject to certain conditions in the Agreement, the Company will pay Whiting-Turner a contract price consisting of the cost of work plus a fee equal to 1.75% of the cost of work. Effective September 13, 2021, the Company entered into a guaranteed maximum price amendment (the "Amendment") to the Agreement to set forth the guaranteed maximum price, as well as the date by which Whiting-Turner is to achieve Substantial Completion (as defined in the Agreement). Under the Amendment, the guaranteed maximum price to be paid by the Company is $84.1 million, subject to certain additions and deductions by change orders as provided by the Agreement. Whiting-Turner’s work under the Agreement represents a portion of the work necessary to complete construction of the ASTRA facility and, therefore the date of Substantial Completion of Whiting-Turner’s work under the Agreement does not equate to the date of completion of ASTRA. The guaranteed maximum price under the Agreement with Whiting-Turner constitutes only a portion of the total estimated cost of building and equipping ASTRA as there are various other third parties engaged in the project for which contracts are not individually material. Legal Proceedings On May 1, 2020, a complaint was filed against the Company in the United States District Court for the Western District of Pennsylvania by PeriphaGen, Inc. ("PeriphaGen"), which also named our Chief Executive Officer and President, R&D, Krish Krishnan and Suma Krishnan, respectively. The complaint alleged breach of contract and misappropriation of trade secrets, which secrets the plaintiff asserted were used to develop our product candidates, including the vector backbones, and our STAR-D platform. The Company answered the complaint on June 26, 2020 by denying the allegations and brought a counterclaim asking the court to declare that the Company did not misappropriate PeriphaGen’s trade secrets or confidential information, and to further declare that the Company is the rightful and sole owner of our product candidates and STAR-D platform. In addition, the Company filed a third-party complaint against two principals of PeriphaGen, James Wechuck and David Krisky, alleging breach of contract and seeking contribution and indemnification from them in the event PeriphaGen is awarded damages. On March 9, 2022, the court officially ordered the parties to attend mediation on March 11, 2022. During the course of the mediation process, the parties were able to exchange information, allowing the parties to value their positions. On March 12, 2022, the Company entered into a binding term sheet to settle the dispute. On April 27, 2022, the Company entered into a final settlement agreement and paid PeriphaGen an upfront payment of $25.0 million on April 28, 2022 for: (i) the release of all claims in the trade secret litigation with PeriphaGen; (ii) the acquisition of certain PeriphaGen assets, and (iii) the grant of a license by PeriphaGen for dermatological applications. Upon approval of the Company's first product by the U.S. Food and Drug Administration, the Company will pay PeriphaGen an additional $12.5 million, followed by three additional $12.5 million contingent milestone payments upon reaching $100.0 million in total cumulative sales, $200.0 million in total cumulative sales and $300.0 million in total cumulative sales. As defined in the settlement agreement, cumulative sales shall include all revenue from sales of the Company products by the Company and its affiliates and licensees, as reported by the Company in its annual Form 10-K filings. If all milestones are achieved, the total consideration for settling the dispute, acquiring certain assets, and granting of a license from PeriphaGen will be $75.0 million. The Company recorded the $25.0 million under litigation settlement expense on the condensed consolidated statements of operations for the nine months ended September 30, 2022. The additional contingent milestone payments were not deemed probable due to uncertainty in the achievement of these milestones as of September 30, 2022, and therefore no additional accrual has been recorded. The Company has received $0 and $768 thousand of insurance proceeds during the three and nine months ended September 30, 2022 and Company recorded an additional $372 thousand as a receivable within prepaid expenses and other current assets on the condensed consolidated balance sheet as management determined that the amount was probable of collection relating to legal defense costs and expenses associated with the PeriphaGen litigation. The reimbursements have been recorded as an offset to our legal fees included in general and administrative expenses on the condensed consolidated statements of operations and within operating activities on the condensed consolidated statements of cash flows.

Capitalization

Capitalization	9 Months Ended
	Sep. 30, 2022
Equity [Abstract]
Capitalization	Capitalization Sale of Common Stock The Company sells shares of common stock from time to time pursuant to its previously executed sales agreement (the "Sales Agreement") with Cowen and Company, LLC ("Cowen") with respect to an at-the-market equity offering program ("ATM Program") finalized on December 31, 2020, under which Cowen acts as the Company's agent and/or principal and may issue and sell from time to time, during the term of the Sales Agreement, shares of common stock having an aggregate offering price up to $150.0 million ("Placement Shares"). The issuance and sale of the Placement Shares by the Company under the Sales Agreement are made pursuant to the Company's effective "shelf" registration statement on Form S-3. During 2021, the Company issued and sold 262,500 shares of common stock at a weighted average price of $66.50 per share for net proceeds of $16.9 million after deducting selling commissions of approximately $524 thousand. During the nine months ended September 30, 2022, the Company issued and sold 434,782 shares of common stock at a weighted average price of $69.00 per share for net proceeds of $29.1 million after deducting selling commissions of approximately $900 thousand, resulting in a remaining $102.5 million available for issuance under the ATM Program. On December 3, 2021, the Company completed an underwritten public offering of 2,866,667 shares of its common stock, including 200,000 shares purchased by the underwriters pursuant to their option to purchase additional shares, at $75.00 per share. Net proceeds to the Company from the offering were $201.9 million after deducting underwriting discounts and commissions of approximately $12.9 million, and other offering expenses payable by the Company of $227 thousand. On February 1, 2021, the Company completed an underwritten public offering of 2,211,538 shares of its common stock, including 288,461 shares purchased by the underwriters pursuant to their option to purchase additional shares, at $65.00 per share. Net proceeds to the Company from the offering were $134.9 million after deducting underwriting discounts and commissions of approximately $8.6 million, and other offering expenses payable by the Company of $198 thousand.

Stock-Based Compensation

Stock-Based Compensation	9 Months Ended
	Sep. 30, 2022
Share-Based Payment Arrangement [Abstract]
Stock-Based Compensation	Stock-Based Compensation Stock Options Options granted to employees and non-employees vest ratably over four-year periods and stock options granted to directors of the company vest ratably over one The Company granted 189,000 and 1,913,000 stock options to employees and directors of the Company during the three and nine months ended September 30, 2022, respectively, and 297,500 and 799,950 stock options to employees and directors of the Company during the three and nine months ended September 30, 2021, respectively. The Company granted zero and 45,000 stock options to non-employees during the three and nine months ended September 30, 2022, respectively, and 50,000 stock options to non-employees during the three and nine months ended September 30, 2021, respectively. The following table summarizes the Company’s stock option activity: Stock Weighted- Weighted- Aggregate Intrinsic Value (In thousands) (1) Outstanding at December 31, 2021 2,043,179 $ 57.00 9.0 $ 31,331 Granted 1,958,000 $ 63.03 Exercised (84,776) $ 46.28 Cancelled or forfeited (412,892) $ 58.90 Expired (5,001) $ 78.19 Outstanding at September 30, 2022 3,498,510 $ 60.38 8.8 $ 37,213 Exercisable at September 30, 2022 637,315 $ 48.74 7.1 $ 14,225 (1) Aggregate intrinsic value represents the difference between the closing stock price of our common stock on September 30, 2022 and the exercise price of outstanding in-the-money options. The total intrinsic value (the amount by which the fair market value exceeds the exercise price) of stock options exercised during the three and nine months ended September 30, 2022 was $1.3 million and $2.1 million, respectively, and during the three and nine months ended September 30, 2021 was $64 thousand and $872 thousand, respectively. The weighted-average grant-date fair value per share of options granted to employees, non-employees, and directors during the three and nine months ended September 30, 2022 was $49.59 and $43.66, respectively, and during the three and nine months ended September 30, 2021 was $34.85 and $43.31, respectively. There was $105.5 million of unrecognized stock-based compensation expense related to employees', non-employees', and directors’ option awards that is expected to be recognized over a weighted-average period of 3.1 years as of September 30, 2022. The Company has recorded aggregate stock-based compensation expense related to the issuance of stock option awards in the condensed consolidated statements of operations for the three and nine months ended September 30, 2022 and 2021 as follows (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2022 2021 2022 2021 Research and development $ 2,184 $ 673 $ 5,547 $ 2,273 General and administrative 6,433 2,502 16,791 6,742 Total stock-based compensation $ 8,617 $ 3,175 $ 22,338 $ 9,015 We capitalize the portion of stock-based compensation that relates to work performed on the construction of new buildings. There was $137 thousand and $423 thousand of stock-based compensation that was capitalized in the three and nine months ended September 30, 2022, respectively, and $79 thousand and $182 thousand of stock-based compensation that was capitalized in the three and nine months ended September 30, 2021, respectively. The fair value of options was estimated at the date of grant using the Black-Scholes valuation model with the following weighted-average assumptions for the three and nine months ended September 30, 2022 and 2021: Three Months Ended September 30, Nine Months Ended September 30, 2022 2021 2022 2021 Expected stock price volatility 78 % 73 % 78 % 73 % Expected term of the award (years) 6.23 6.10 6.21 6.18 Risk-free interest rate 3.20 % 1.13 % 2.27 % 1.05 % Weighted average exercise price $ 70.91 $ 53.69 $ 63.03 $ 67.15 Forfeiture rate — % — % — % — % Restricted Stock Awards Restricted stock awards ("RSAs") granted to employees vest ratably over a four-year period. The Company granted zero RSAs to employees of the Company during the three and nine months ended September 30, 2022, respectively, and zero and 98,800 RSAs to employees of the Company during the three and nine months ended September 30, 2021, respectively. Number of Shares Weighted Average Non-vested RSAs as of December 31, 2021 98,800 $ 78.89 Granted — $ — Vested (14,321) $ 78.89 Surrendered or forfeited (17,879) $ 78.89 Non-vested RSAs as of September 30, 2022 66,600 $ 78.89 There was $4.2 million of unrecognized stock-based compensation expense related to employees’ awards that is expected to be recognized over a weighted-average period of 2.4 years as of September 30, 2022. The Company recorded stock-based compensation expense related to RSAs in the condensed consolidated statement of operations for the three and nine months ended September 30, 2022 and 2021 as follows (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2022 2021 2022 2021 General and administrative $ 441 $ 491 $ 1,340 $ 1,159 Total stock-based compensation $ 441 $ 491 $ 1,340 $ 1,159

Subsequent Events

Subsequent Events	9 Months Ended
	Sep. 30, 2022
Subsequent Events [Abstract]
Subsequent Events	Subsequent EventsThe Company evaluates events or transactions that occur after the balance sheet date, but prior to the issuance of the financial statements, to identify matters that require disclosure. The Company concluded that no subsequent events have occurred that would require recognition or disclosure in the condensed consolidated financial statements.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2022
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying interim condensed consolidated financial statements have been prepared in conformity with generally accepted accounting principles in the United States of America (“GAAP”). In the opinion of management, all adjustments, which consist of all normal recurring adjustments necessary for a fair presentation of the Company's financial position and results of operations for the interim periods presented, are reflected in the interim condensed consolidated financial statements. All intercompany balances and transactions have been eliminated in consolidation. Certain prior period amounts have been reclassified to conform to the current period presentation. The reclassified amounts have no impact on the Company’s previously reported financial position or results of operation. 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 unaudited interim condensed consolidated financial statements should be read in conjunction with the Company’s audited consolidated financial statements and the notes thereto included in the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2021, as filed with the SEC on February 28, 2022.
Risks and Uncertainties	Risks and Uncertainties The coronavirus ("COVID-19") pandemic has resulted, and is likely to continue to result, in significant national and global economic uncertainty and may adversely affect the Company's business. The Company is continuing to actively monitor the impact of the COVID-19 pandemic and the related effects on its financial condition, liquidity, operations, suppliers, industry, and workforce. The full extent, consequences, and duration of the COVID-19 pandemic and the resulting impact on the Company cannot currently be predicted. The Company will continue to evaluate the impact that the pandemic could have on the operations, financial position, and the results of operations and cash flows during fiscal year 2022.
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 condensed consolidated 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 are used in the following areas including stock-based compensation expense, accrued expenses, the fair value of financial instruments, the incremental borrowing rate for lease liabilities, and the valuation allowance included in the deferred income tax calculation.
Segment and Geographical Information	Segment and Geographical InformationOperating segments are defined as components of an enterprise about which separate discrete information is available for evaluation by the chief operating decision maker, or decision-making group, in deciding how to allocate resources and in assessing performance. The Company and the Company’s chief operating decision maker view the Company’s operations and manage its business in one operating segment, which is the business of developing and commercializing pharmaceutical products.
Concentrations of Credit Risk and Off-Balance Sheet Risk	Concentrations of Credit Risk and Off-Balance Sheet Risk Financial instruments that potentially subject the Company to credit risk consist of cash, cash equivalents and investments. The Company’s policy is to invest its cash, cash equivalents and investments in money market funds, corporate bonds, commercial paper, government agency securities and various other bank deposit accounts. The counterparties to the agreements relating to the Company’s investments consist of financial institutions of high credit standing. The Company is exposed to credit risk in the event of default by the financial institutions to the extent amounts recorded on the condensed consolidated balance sheets are in excess of insured limits. The Company has not experienced any credit losses in such accounts and does not believe it is exposed to any significant credit risk on these funds. The Company has no financial instruments with off-balance sheet risk of loss.
Cash, Cash Equivalents and Investments	Cash, Cash Equivalents and Investments Cash and cash equivalents consist of money market funds and bank deposits. Cash equivalents are defined as short-term, highly liquid investments with original maturities of 90 days or less at the date of purchase. Investments with maturities of less than one year are classified as short-term investments on the condensed consolidated balance sheets and consist of commercial paper, corporate bonds, and government agency securities. Investments with maturities of greater than one year are classified as long-term investments on the condensed consolidated balance sheets and consist of corporate bonds and government agency securities. Accrued interest on corporate bonds and government agency securities are also classified as short-term investments.
Fair Value of Financial Instruments	Fair Value of Financial Instruments Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. There is a three-level hierarchy that prioritizes the inputs used in determining fair value by their reliability and preferred use, as follows: • Level 1 — Valuations based on quoted prices in active markets for identical assets or liabilities. • Level 2 — Valuations based on quoted prices in active markets for similar assets and liabilities, quoted prices for identical or similar assets or liabilities in inactive markets, or other inputs that are observable or can be corroborated by observable market data. • Level 3 — Valuations based on inputs that are both significant to the fair value measurement and unobservable. To the extent that a valuation is based on models or inputs that are less observable, or unobservable in the market, the determination of fair value requires more judgment. Accordingly, the degree of judgment exercised by the Company in determining fair value is greatest for instruments categorized within Level 3. A financial instrument’s level within the fair value hierarchy is based on the lowest level of any input that is significant to the fair value measurement. There have been no significant changes to the valuation methods utilized by the Company during the periods presented. There have been no transfers between Level 1, Level 2, and Level 3 in any periods presented. The carrying amounts of financial instruments consisting of cash and cash equivalents, investments, prepaid expenses and other current assets, accounts payable, accrued expenses and other current liabilities included in the Company’s condensed consolidated financial statements, are reasonable estimates of fair value, primarily due to their short maturities. Our available-for-sale, short-term and long-term investments, which consist of commercial paper, corporate bonds, and U.S. government agency securities are considered to be Level 2 valuations. The fair value of Level 2 financial assets is determined using inputs that are observable in the market or can be derived principally from or corroborated by observable market data, such as pricing for similar securities, recently executed transactions, cash flow models with yield curves, and benchmark securities. In addition, Level 2 financial instruments are valued using comparisons to like-kind financial instruments and models that use readily observable market data as their basis.
Property and Equipment, net	Property and Equipment, net Property and equipment, net, is stated at cost, less accumulated depreciation. Maintenance and repairs that do not improve or extend the lives of the respective assets are expensed to operations as incurred, while costs of major additions and betterments are capitalized. Upon disposal, the related cost and accumulated depreciation is removed from the accounts and any resulting gain or loss is included in the results of operations. Depreciation is recorded using the straight-line method over the estimated useful lives of the respective assets, which are as follows: Computer equipment and software 3 - 7 years Laboratory and manufacturing equipment 3 - 20 years Furniture and fixtures 3 - 7 years Leasehold improvement lesser of remaining useful life or remaining lease term The Company reviews the estimated useful lives of its property and equipment on a continuing basis. In evaluating the useful lives, the Company considers how long assets will remain functionally effective, whether the technology continues to be relevant and considers other competitive and economic factors. If the assessment indicates that the assets will be used for a shorter or longer period than previously anticipated, the useful life of the assets is adjusted, resulting in a change in estimate. Changes in estimates are accounted for on a prospective basis by depreciating the current carrying values of the assets over their revised remaining useful lives. The review performed by the Company in the current year indicated that certain pieces of lab equipment would be functional for a longer term than previously estimated and as a result, the Company increased the useful lives of these assets from 7 to 15 years. This change was effective and accounted for prospectively beginning in Q3 2022. The effect of this change in useful life estimate did not result in a material change to depreciation expense.
Impairment of Long-Lived Assets	Impairment of Long-Lived Assets The Company evaluates long-lived assets for potential impairment when events or changes in circumstances indicate the carrying value of the assets may not be recoverable. An impairment loss would be recognized when estimated future cash flows expected to result from the use of the asset and its eventual disposition are less than the carrying amount of the asset. The Company has not recognized any impairment losses for the three and nine months ended September 30, 2022 and 2021, respectively.
Leases	Leases The Company accounts for its lease agreements in accordance with FASB ASC Topic 842, Leases . Right-of-use lease assets represent the right to use an underlying asset during the lease term and the lease obligations represent the commitment to make lease payments arising from the lease. Right-of-use lease assets and obligations are recognized based on the present value of remaining lease payments over the lease term. As the Company’s existing lease agreements do not provide an implicit rate and as the Company does not have any external borrowings, the Company has used an estimated incremental borrowing rate based on the information available at lease commencement in determining the present value of lease payments. Operating lease expense is recognized on a straight-line basis over the lease term. Variable lease expense is recognized in the period in which the obligation for the payment is incurred. In addition, the Company also has made an accounting policy election to exclude leases with an initial term of twelve months or less from its balance sheet and to account for lease and non-lease components of its operating leases as a single component. For lease arrangements where it has been determined that the Company has control over an asset that is under construction and is thus considered the accounting owner of the asset during the construction period, the Company records a construction in progress asset and corresponding financial obligation on the condensed consolidated balance sheet. Once the construction is complete, an assessment is performed to determine whether the lease meets certain sale-leaseback criteria. If the sale-leaseback criteria are determined to be met, the Company will remove the asset and related financial obligation from the condensed consolidated balance sheet and treat the lease as either an operating or finance lease based on an assessment of the guidance. If, upon completion of construction, the project does not meet the "sale-leaseback" criteria, the lease will be treated as a financing obligation and the Company will depreciate the asset over its estimated useful life for financial reporting purposes once the asset has been placed into service.
Research and Development Expenses	Research and Development Expenses Research and development costs are charged to expense as incurred in performing research and development activities. These costs include employee compensation costs, facilities and overhead, preclinical and clinical activities, clinical manufacturing costs, contract management services, regulatory and other related costs. The Company estimates contract research and clinical trials materials manufacturing expenses based on the services performed pursuant to contracts with research organizations and manufacturing organizations that manufacture materials used in the Company’s ongoing preclinical and clinical studies. Non-refundable advanced payments for goods or services to be received in the future for use in research and development activities are deferred and capitalized. The capitalized amounts are expensed as the related goods are delivered or the services are performed. In accruing service fees, the Company estimates the time period over which services will be performed and the level of effort to be expended in each period. These estimates are based on communications with the third-party service providers and the Company’s estimates of accrued expenses using information available at each balance sheet date. If the actual timing of the performance of services or the level of effort varies from the estimate, the Company will adjust the accrual accordingly.
Stock-Based Compensation Expense	Stock-Based Compensation Expense The Company applies the fair value recognition provisions of Financial Accounting Standards Board ("FASB") Accounting Standards Codification, or ASC, Topic 718, Compensation—Stock Compensation ("ASC 718"), to account for stock-based compensation. Compensation costs related to stock options granted are based on the estimated fair value of the awards on the date of grant. ASC 718 requires all stock-based payments, including grants of stock options and restricted stock, to be recognized in the consolidated statements of operations based on their grant-date fair values. Compensation expense is recognized on a straight-line basis based on the grant-date fair value over the associated service period of the award, which is generally the vesting term. The Company estimates the fair value of its stock options using the Black-Scholes option pricing model, which requires the input of subjective assumptions, including: (i) the expected stock price volatility; (ii) the expected term of the award; (iii) the risk-free interest rate; and (iv) expected dividends. Once the Company's own sufficient historical volatility data was
Comprehensive Loss	Comprehensive Loss Comprehensive loss is defined as the change in equity during a period from transactions from non-owner sources. Unrealized gains or losses on available-for-sale securities is a component of other comprehensive gains or losses. We have not recorded any reclassifications from other comprehensive gains or losses to net loss during any period presented.
Recent Accounting Pronouncements	Recent Accounting Pronouncements From time to time, new accounting pronouncements are issued by the FASB or other accounting standard setting bodies that the Company adopts as of the specified effective date. The Company does not believe that the adoption of recently issued standards have or may have a material impact on the condensed consolidated statements or disclosures.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	9 Months Ended
	Sep. 30, 2022
Accounting Policies [Abstract]
Summary of Estimated Useful Lives of Assets	Depreciation is recorded using the straight-line method over the estimated useful lives of the respective assets, which are as follows: Computer equipment and software 3 - 7 years Laboratory and manufacturing equipment 3 - 20 years Furniture and fixtures 3 - 7 years Leasehold improvement lesser of remaining useful life or remaining lease term

Net Loss Per Share Attributab_2

Net Loss Per Share Attributable to Common Stockholders (Tables)	9 Months Ended
	Sep. 30, 2022
Earnings Per Share [Abstract]
Schedule of Net Loss Per Share Attributable to Common Stockholders	Three Months Ended Nine Months Ended (In thousands, except share and per share data) 2022 2021 2022 2021 Numerator: Net loss $ (29,850) $ (15,589) $ (107,923) $ (47,764) Denominator: Weighted-average basic and diluted common shares 25,619,125 22,212,266 25,428,097 21,893,656 Basic and diluted net loss per $ (1.17) $ (0.70) $ (4.24) $ (2.18)

Fair Value Instruments (Tables)

Fair Value Instruments (Tables)	9 Months Ended
	Sep. 30, 2022
Fair Value Disclosures [Abstract]
Summary of Cash, Cash Equivalents and Available-for-Sale Securities	The following tables show the Company’s cash, cash equivalents and available-for-sale securities by significant investment category as of September 30, 2022 and December 31, 2021, respectively (in thousands): September 30, 2022 Amortized Cost Gross Gross Aggregate Fair Cash and Cash Short-term Marketable Securities (1) Long-term Marketable Securities (2) Level 1: Cash and cash equivalents $ 186,409 $ — $ — $ 186,409 $ 186,409 $ — $ — Subtotal 186,409 — — 186,409 186,409 — — Level 2: Commercial paper 52,777 2 (41) 52,738 — 52,738 — Corporate bonds 94,415 — (886) 93,529 — 87,291 6,238 U.S. government agency securities 74,824 36 (559) 74,301 — 67,982 6,319 Subtotal 222,016 38 (1,486) 220,568 — 208,011 12,557 Total $ 408,425 $ 38 $ (1,486) $ 406,977 $ 186,409 $ 208,011 $ 12,557 December 31, 2021 Amortized Cost Gross Gross Aggregate Fair Cash and Cash Short-term Marketable Securities (1) Long-term Marketable Securities (2) Level 1: Cash and cash equivalents $ 341,246 $ — $ — $ 341,246 $ 341,246 $ — $ — Subtotal 341,246 — — 341,246 341,246 — — Level 2: Commercial paper 40,469 1 (4) 40,466 — 40,466 — Corporate bonds 83,300 10 (114) 83,196 — 35,768 47,428 U.S. government agency securities 37,621 — (62) 37,559 — 20,616 16,943 Subtotal 161,390 11 (180) 161,221 — 96,850 64,371 Total $ 502,636 $ 11 $ (180) $ 502,467 $ 341,246 $ 96,850 $ 64,371 (1) The Company’s short-term marketable securities mature in one year or less. (2) The Company's long-term marketable securities mature between one year and two years.

Balance Sheet Components (Table

Balance Sheet Components (Tables)	9 Months Ended
	Sep. 30, 2022
Balance Sheet Related Disclosures [Abstract]
Schedule of Property and Equipment, Net	Property and equipment, net consist of the following (in thousands): September 30, December 31, Construction in progress $ 130,071 $ 104,340 Leasehold improvements 21,503 5,723 Furniture and fixtures 949 891 Computer equipment and software 96 85 Laboratory and manufacturing equipment 10,968 5,530 Total property and equipment 163,587 116,569 Accumulated depreciation (5,801) (4,214) Property and equipment, net $ 157,786 $ 112,355
Schedule of Accrued Expenses And Other Current Liabilities	Accrued expenses and other current liabilities consisted of the following (in thousands): September 30, December 31, Accrued construction in progress $ 10,905 $ 9,606 Accrued professional fees 2,960 2,011 Accrued payroll and benefits 3,934 2,882 Accrued preclinical and clinical expenses 2,325 1,602 Accrued financing costs 10 26 Accrued taxes 122 83 Other current liabilities 468 87 Total $ 20,724 $ 16,297

Commitments and Contingencies (

Commitments and Contingencies (Tables)	9 Months Ended
	Sep. 30, 2022
Commitments and Contingencies Disclosure [Abstract]
Schedule of Future Minimum Operating Lease Payments	As of September 30, 2022, future minimum commitments under the Company’s operating leases with lease terms in excess of 12 months were as follows (in thousands): Operating 2022 (remaining three months) $ 404 2023 1,640 2024 1,539 2025 1,277 2026 1,277 Thereafter 12,062 Future minimum operating lease payments $ 18,199 Less: Interest 9,077 Present value of lease liability $ 9,122
Schedule of Supplemental Condensed Consolidated Balance Sheet Information Related to Leases	Supplemental condensed consolidated balance sheet information related to leases is as follows: September 30, 2022 December 31, 2021 Operating leases: Right-of-use assets $ 8,253 $ 7,228 Current portion of lease liability 1,547 1,041 Lease liability 7,575 6,983 Total lease liability $ 9,122 $ 8,024 Weighted average remaining lease term, in years 12.6 14.4 Weighted average discount rate 9.4 % 9.5 %
Lease, Cost	The components of the Company's lease expense are as follows: Three Months Ended Nine Months Ended 2022 2021 2022 2021 Lease cost: Operating lease expense $ 399 $ 339 $ 1,200 $ 836 Variable lease expense 48 65 168 183 Total lease expense $ 447 $ 404 $ 1,368 $ 1,019

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	9 Months Ended
	Sep. 30, 2022
Share-Based Payment Arrangement [Abstract]
Schedule of Company's Stock Option Activity	The following table summarizes the Company’s stock option activity: Stock Weighted- Weighted- Aggregate Intrinsic Value (In thousands) (1) Outstanding at December 31, 2021 2,043,179 $ 57.00 9.0 $ 31,331 Granted 1,958,000 $ 63.03 Exercised (84,776) $ 46.28 Cancelled or forfeited (412,892) $ 58.90 Expired (5,001) $ 78.19 Outstanding at September 30, 2022 3,498,510 $ 60.38 8.8 $ 37,213 Exercisable at September 30, 2022 637,315 $ 48.74 7.1 $ 14,225 (1) Aggregate intrinsic value represents the difference between the closing stock price of our common stock on September 30, 2022 and the exercise price of outstanding in-the-money options.
Summary of Stock Based Compensation Expense Related to Issuance of Stock Option Awards and Restricted Stock Awards	The Company has recorded aggregate stock-based compensation expense related to the issuance of stock option awards in the condensed consolidated statements of operations for the three and nine months ended September 30, 2022 and 2021 as follows (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2022 2021 2022 2021 Research and development $ 2,184 $ 673 $ 5,547 $ 2,273 General and administrative 6,433 2,502 16,791 6,742 Total stock-based compensation $ 8,617 $ 3,175 $ 22,338 $ 9,015 The Company recorded stock-based compensation expense related to RSAs in the condensed consolidated statement of operations for the three and nine months ended September 30, 2022 and 2021 as follows (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2022 2021 2022 2021 General and administrative $ 441 $ 491 $ 1,340 $ 1,159 Total stock-based compensation $ 441 $ 491 $ 1,340 $ 1,159
Fair Value of Stock Options, Valuation Assumptions	The fair value of options was estimated at the date of grant using the Black-Scholes valuation model with the following weighted-average assumptions for the three and nine months ended September 30, 2022 and 2021: Three Months Ended September 30, Nine Months Ended September 30, 2022 2021 2022 2021 Expected stock price volatility 78 % 73 % 78 % 73 % Expected term of the award (years) 6.23 6.10 6.21 6.18 Risk-free interest rate 3.20 % 1.13 % 2.27 % 1.05 % Weighted average exercise price $ 70.91 $ 53.69 $ 63.03 $ 67.15 Forfeiture rate — % — % — % — %
Share-based Payment Arrangement, Restricted Stock and Restricted Stock Unit, Activity	Number of Shares Weighted Average Non-vested RSAs as of December 31, 2021 98,800 $ 78.89 Granted — $ — Vested (14,321) $ 78.89 Surrendered or forfeited (17,879) $ 78.89 Non-vested RSAs as of September 30, 2022 66,600 $ 78.89

Organization - Additional Infor

Organization - Additional Information (Detail) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Accounting Policies [Abstract]
Accumulated deficit	$ 248,707	$ 140,784
Cash, cash equivalents and short-term investments	$ 394,400

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Additional Information (Detail)	3 Months Ended		6 Months Ended	9 Months Ended
	Sep. 30, 2022 USD ($)	Sep. 30, 2021 USD ($)	Jun. 30, 2022	Sep. 30, 2022 USD ($) segment	Sep. 30, 2021 USD ($)
Significant Accounting Policies [Line Items]
Number of operating segment | segment				1
Laboratory and manufacturing equipment
Significant Accounting Policies [Line Items]
Estimated useful lives of assets	15 years		7 years
Recognized impairment losses for long lived assets | $	$ 0	$ 0		$ 0	$ 0

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Summary of Estimated Useful Lives of Assets (Detail)	3 Months Ended	6 Months Ended	9 Months Ended
	Sep. 30, 2022	Jun. 30, 2022	Sep. 30, 2022
Computer equipment and software | Minimum
Property, Plant and Equipment [Line Items]
Estimated useful lives of assets			3 years
Computer equipment and software | Maximum
Property, Plant and Equipment [Line Items]
Estimated useful lives of assets			7 years
Laboratory and manufacturing equipment
Property, Plant and Equipment [Line Items]
Estimated useful lives of assets	15 years	7 years
Laboratory and manufacturing equipment | Minimum
Property, Plant and Equipment [Line Items]
Estimated useful lives of assets			3 years
Laboratory and manufacturing equipment | Maximum
Property, Plant and Equipment [Line Items]
Estimated useful lives of assets			20 years
Furniture and fixtures | Minimum
Property, Plant and Equipment [Line Items]
Estimated useful lives of assets			3 years
Furniture and fixtures | Maximum
Property, Plant and Equipment [Line Items]
Estimated useful lives of assets			7 years

Net Loss Per Share Attributab_3

Net Loss Per Share Attributable to Common Stockholders - Additional Information (Detail) - shares	9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021
Earnings Per Share [Abstract]
Common share equivalents outstanding, excluded from the calculation of diluted net loss per common share	3,565,110	1,900,638

Net Loss Per Share Attributab_4

Net Loss Per Share Attributable to Common Stockholders - Schedule of Basic and Diluted Net Loss Per Share and Per Unit (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2022	Sep. 30, 2021
Numerator:
Net loss	$ (29,850)	$ (28,108)	$ (49,965)	$ (15,589)	$ (16,363)	$ (15,812)	$ (107,923)	$ (47,764)
Denominator:
Weighted-average common shares outstanding: basic	25,619,125			22,212,266			25,428,097	21,893,656
Weighted-average common shares outstanding: diluted	25,619,125			22,212,266			25,428,097	21,893,656
Net loss per common share: basic (in dollars per share)	$ (1.17)			$ (0.70)			$ (4.24)	$ (2.18)
Net loss per common share: diluted (in dollars per share)	$ (1.17)			$ (0.70)			$ (4.24)	$ (2.18)

Fair Value Instruments - Summar

Fair Value Instruments - Summary of Cash, Cash Equivalents and Available-for-Sale Securities (Detail) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	$ 186,409	$ 341,246
Gross Unrealized Gains	38	11
Gross Unrealized Losses	(1,486)	(180)
Amortized Cost	408,425	502,636
Aggregate fair value, total	406,977	502,467
Commercial paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Amortized Cost	52,777	40,469
Gross Unrealized Gains	2	1
Gross Unrealized Losses	(41)	(4)
Aggregate Fair Value	52,738	40,466
Corporate bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Amortized Cost	94,415	83,300
Gross Unrealized Gains	0	10
Gross Unrealized Losses	(886)	(114)
Aggregate Fair Value	93,529	83,196
U.S. government agency securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Amortized Cost	74,824	37,621
Gross Unrealized Gains	36	0
Gross Unrealized Losses	(559)	(62)
Aggregate Fair Value	74,301	37,559
Cash and Cash Equivalents
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Aggregate fair value, total	186,409	341,246
Short-term Marketable Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Aggregate fair value, total	208,011	96,850
Short-term Marketable Securities | Commercial paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Aggregate Fair Value	52,738	40,466
Short-term Marketable Securities | Corporate bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Aggregate Fair Value	87,291	35,768
Short-term Marketable Securities | U.S. government agency securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Aggregate Fair Value	67,982	20,616
Long-term Marketable Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Aggregate fair value, total	12,557	64,371
Long-term Marketable Securities | Commercial paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Aggregate Fair Value	0	0
Long-term Marketable Securities | Corporate bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Aggregate Fair Value	6,238	47,428
Long-term Marketable Securities | U.S. government agency securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Aggregate Fair Value	6,319	16,943
Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	186,409	341,246
Aggregate Fair Value	186,409	341,246
Level 1 | Cash and Cash Equivalents
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	186,409	341,246
Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Amortized Cost	222,016	161,390
Gross Unrealized Gains	38	11
Gross Unrealized Losses	(1,486)	(180)
Aggregate Fair Value	220,568	161,221
Level 2 | Short-term Marketable Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Aggregate Fair Value	$ 208,011	96,850
Debt securities, available-for-sale, term	1 year
Level 2 | Long-term Marketable Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Aggregate Fair Value	$ 12,557	64,371
Level 2 | Long-term Marketable Securities | Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities, available-for-sale, term	1 year
Level 2 | Long-term Marketable Securities | Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities, available-for-sale, term	2 years
Cash and cash equivalents | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	$ 186,409	341,246
Aggregate Fair Value	186,409	341,246
Cash and cash equivalents | Level 1 | Cash and Cash Equivalents
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	$ 186,409	$ 341,246

Balance Sheet Components - Sche

Balance Sheet Components - Schedule of Property and Equipment, Net (Detail) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 163,587	$ 116,569
Accumulated depreciation	(5,801)	(4,214)
Property and equipment, net	157,786	112,355
Construction in progress
Property, Plant and Equipment [Line Items]
Total property and equipment	130,071	104,340
Leasehold improvements
Property, Plant and Equipment [Line Items]
Total property and equipment	21,503	5,723
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Total property and equipment	949	891
Computer equipment and software
Property, Plant and Equipment [Line Items]
Total property and equipment	96	85
Laboratory and manufacturing equipment
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 10,968	$ 5,530

Balance Sheet Components - Addi

Balance Sheet Components - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Balance Sheet Related Disclosures [Abstract]
Depreciation expense	$ 669	$ 474	$ 1,600	$ 1,400

Balance Sheet Components - Sc_2

Balance Sheet Components - Schedule of Accrued Expenses And Other Current Liabilities (Detail) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Balance Sheet Related Disclosures [Abstract]
Accrued construction in progress	$ 10,905	$ 9,606
Accrued professional fees	2,960	2,011
Accrued payroll and benefits	3,934	2,882
Accrued preclinical and clinical expenses	2,325	1,602
Accrued financing costs	10	26
Accrued taxes	122	83
Other current liabilities	468	87
Total	$ 20,724	$ 16,297

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail) ft² in Thousands, $ in Thousands

3 Months Ended

9 Months Ended

Apr. 28, 2022 USD ($)

Mar. 12, 2022 USD ($)

Oct. 15, 2020 USD ($)

Sep. 30, 2022 USD ($) ft²

Sep. 30, 2021 USD ($)

Sep. 30, 2022 USD ($) ft² milestone

Sep. 30, 2021 USD ($)

Dec. 31, 2023 USD ($)

Dec. 31, 2022 USD ($)

May 16, 2022

Dec. 15, 2021

Sep. 13, 2021 USD ($)

Oct. 05, 2020 USD ($)

May 26, 2016 ft²

Operating Leased Assets [Line Items]

Cash contribution

$ 2,400

Purchase price of potential purchase

$ 9,400

Construction in progress, gross

10,000

Finance lease, liability

$ 10,000

Escrow deposit

$ 1,500

Lessor, operating lease, liability, annual lease payments

$ 82

Cumulative escalation clause

0.10

Cumulative escalation clause, term

5 years

Future minimum operating lease payments

$ 18,199

$ 18,199

Loss contingency, guaranteed maximum price to be paid

$ 84,100

Litigation settlement

0

$ 0

25,000

$ 0

Proceeds from insurance settlement, operating activities

0

768

Gain related to litigation settlement

372

Forecast

Operating Leased Assets [Line Items]

Future minimum operating lease payments

$ 121

$ 40

PeriphaGen

Operating Leased Assets [Line Items]

Litigation settlement

$ 25,000

25,000

Litigation settlement, amount awarded to other party

$ 12,500

Number of milestones | milestone

3

Litigation settlement, total consideration

$ 75,000

PeriphaGen | Milestone Two

Operating Leased Assets [Line Items]

Litigation settlement, amount awarded to other party

$ 12,500

Litigation settlement, milestone payments, sales threshold

200,000

PeriphaGen | Milestone Three

Operating Leased Assets [Line Items]

Litigation settlement, amount awarded to other party

12,500

Litigation settlement, milestone payments, sales threshold

300,000

PeriphaGen | Milestone One

Operating Leased Assets [Line Items]

Litigation settlement, amount awarded to other party

12,500

Litigation settlement, milestone payments, sales threshold

$ 100,000

Clinical Supply Agreements

Operating Leased Assets [Line Items]

Estimated remaining commitment

2,400

2,400

Project management service fee

2,100

744

5,100

3,300

Other Contractual Obligations

Operating Leased Assets [Line Items]

Estimated remaining commitment

6,200

6,200

Project management service fee

3,200

$ 1,800

9,500

$ 4,100

ASTRA Facility

Operating Leased Assets [Line Items]

Contractual obligation

$ 10,300

$ 10,300

Cost of work, percentage

0.0175

0.0175

2016 Lease Agreement

Operating Leased Assets [Line Items]

Additional area of real estate property leased | ft²

54

54

47

Short-Term Amendment

Operating Leased Assets [Line Items]

Additional area of real estate property leased | ft²

7

7

Boston, Massachusetts Lease

Operating Leased Assets [Line Items]

Operating lease, term of contract

3 years

Switzerland Lease

Operating Leased Assets [Line Items]

Operating lease, term of contract

16 months

Commitments and Contingencies_2

Commitments and Contingencies - Schedule of Future Minimum Operating Lease Payments (Detail) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Commitments and Contingencies Disclosure [Abstract]
2022 (remaining three months)	$ 404
2023	1,640
2024	1,539
2025	1,277
2026	1,277
Thereafter	12,062
Future minimum operating lease payments	18,199
Less: Interest	9,077
Present value of lease liability	$ 9,122	$ 8,024

Commitments and Contingencies_3

Commitments and Contingencies - Schedule of Supplemental Condensed Consolidated Balance Sheet Information Related to Leases (Detail) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Lessee, Operating Lease, Liability, Payment, Due [Abstract]
Right-of-use assets	$ 8,253	$ 7,228
Current portion of lease liability	1,547	1,041
Lease liability	7,575	6,983
Total lease liability	$ 9,122	$ 8,024
Weighted average remaining lease term, in years	12 years 7 months 6 days	14 years 4 months 24 days
Weighted average discount rate	9.40%	9.50%

Commitments and Contingencies_4

Commitments and Contingencies - Schedule of Lease Costs (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Commitments and Contingencies Disclosure [Abstract]
Operating lease costs	$ 399	$ 339	$ 1,200	$ 836
Variable lease costs	48	65	168	183
Lease, Cost	$ 447	$ 404	$ 1,368	$ 1,019

Capitalization - Additional Inf

Capitalization - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands				9 Months Ended	12 Months Ended
	Apr. 05, 2022	Dec. 03, 2021	Feb. 01, 2021	Sep. 30, 2022	Dec. 31, 2021	Dec. 31, 2020
Schedule of Capitalization, Equity [Line Items]
Offering expenses		$ 227	$ 198
Placement Shares
Schedule of Capitalization, Equity [Line Items]
Sale of stock, aggregate offering price						$ 150,000
Public Offering
Schedule of Capitalization, Equity [Line Items]
Sale of stock, number of shares issued in transaction	434,782	2,866,667	2,211,538		262,500
Sale of stock, price per share (in dollars per share)		$ 75	$ 65	$ 69	$ 66.50
Proceeds from initial offering of shares	$ 29,100	$ 201,900	$ 134,900
Underwriting discounts and commissions		$ 12,900	$ 8,600
ATM Program
Schedule of Capitalization, Equity [Line Items]
Proceeds from initial offering of shares					$ 16,900
Underwriting discounts and commissions				$ 900	$ 524
Sale of stock, remaining available issuance amount				$ 102,500
Over-Allotment Option
Schedule of Capitalization, Equity [Line Items]
Sale of stock, number of shares issued in transaction		200,000	288,461

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021	Dec. 31, 2021
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock option expiration period			10 years
Stock options granted (in shares)			1,958,000
Intrinsic value of options exercised	$ 1,300	$ 64	$ 2,100	$ 872
Share-based payment arrangement, amount capitalized	$ 137	$ 79	$ 423	$ 182
Director
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options granted (in shares)	189,000	297,500	1,913,000	799,950
Stock Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares remaining available for grant	607,366		607,366
Share-based Payment Arrangement, Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock option vesting period			4 years
Weighted-average grant-date fair value per share of options granted (in dollars per share)	$ 49.59	$ 34.85	$ 43.66	$ 43.31
Stock-based compensation expense	$ 8,617	$ 3,175	$ 22,338	$ 9,015
Share-based Payment Arrangement, Option | Director
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized stock-based compensation expense	$ 105,500		$ 105,500
Estimated weighted average period			3 years 1 month 6 days
Non-Employee Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options granted (in shares)	0	50,000	45,000	50,000
Non-Employee Stock Option | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock option vesting period			1 year
Non-Employee Stock Option | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock option vesting period			4 years
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock award granted (in shares)	0	0	0	98,800
Restricted stock award outstanding (in shares)	66,600		66,600		98,800
Unrecognized stock-based compensation expense	$ 4,200		$ 4,200
Estimated weighted average period			2 years 4 months 24 days
Stock-based compensation expense	$ 441	$ 491	$ 1,340	$ 1,159
Restricted Stock | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock option vesting period			4 years
Incentive Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares remaining available for grant	7,223		7,223

Stock-Based Compensation - Sche

Stock-Based Compensation - Schedule of Company's Stock Option Activity (Detail) $ / shares in Units, $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2022 USD ($) $ / shares shares	Dec. 31, 2021 USD ($) $ / shares shares
Stock Options Outstanding
Beginning balance (in shares) | shares	2,043,179
Granted (in shares) | shares	1,958,000
Exercised (in shares) | shares	(84,776)
Cancelled or forfeited (in shares) | shares	(412,892)
Expired (in shares) | shares	(5,001)
Ending balance (in shares) | shares	3,498,510	2,043,179
Exercisable end of period (in shares) | shares	637,315
Weighted- average Exercise Price
Beginning balance (in dollars per share) | $ / shares	$ 57
Granted (in dollars per share) | $ / shares	63.03
Exercised (in dollars per share) | $ / shares	46.28
Cancelled or forfeited (in dollars per share) | $ / shares	58.90
Exercised (in dollars per share) | $ / shares	78.19
Ending balance (in dollars per share) | $ / shares	60.38	$ 57
Exercisable end of period (in dollars per share) | $ / shares	$ 48.74
Weighted- average Remaining Contractual Life (Years)
Weighted-average remaining contractual life (Years)	8 years 9 months 18 days	9 years
Weighted-average remaining contractual life (Years), exercisable	7 years 1 month 6 days
Aggregate Intrinsic Value
Aggregate intrinsic value, outstanding | $	$ 37,213	$ 31,331
Exercisable at September 30, 2022 | $	$ 14,225

Stock-Based Compensation - Summ

Stock-Based Compensation - Summary of Stock Based Compensation Expense Related to Issuance of Stock Option Awards and Restricted Stock Awards (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Share-based Payment Arrangement, Option
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation	$ 8,617	$ 3,175	$ 22,338	$ 9,015
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation	441	491	1,340	1,159
Research and development | Share-based Payment Arrangement, Option
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation	2,184	673	5,547	2,273
General and administrative | Share-based Payment Arrangement, Option
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation	6,433	2,502	16,791	6,742
General and administrative | Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation	$ 441	$ 491	$ 1,340	$ 1,159

Stock-Based Compensation - Fair

Stock-Based Compensation - Fair Value of Stock Options, Valuation Assumptions (Detail) - Share-based Payment Arrangement, Option - $ / shares	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected stock price volatility	78%	73%	78%	73%
Expected term of the award (years)	6 years 2 months 23 days	6 years 1 month 6 days	6 years 2 months 15 days	6 years 2 months 4 days
Risk-free interest rate	3.20%	1.13%	2.27%	1.05%
Weighted average exercise price (in dollars per share)	$ 70.91	$ 53.69	$ 63.03	$ 67.15
Forfeiture rate	0%	0%	0%	0%

Stock-Based Compensation - Sc_2

Stock-Based Compensation - Schedule of Company's Restricted Stock Activity (Details) - Restricted Stock - $ / shares	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Number of Shares
Beginning balance (in shares)			98,800
Granted (in shares)	0	0	0	98,800
Vested (in shares)			(14,321)
Surrendered or forfeited (in shares)			(17,879)
Ending balance (in shares)	66,600		66,600
Weighted Average Grant Date Fair Value
Beginning balance (in dollars per share)			$ 78.89
Granted (in dollars per share)			0
Vested (in dollars per share)			78.89
Surrendered or forfeited (in dollars per share)			78.89
Ending balance (in dollars per share)	$ 78.89		$ 78.89