Adverum Biotechnologies (ADVM) 10-Q 10 Nov 22 2022 Q3 Quarterly report Financial data

Cover Page

Cover Page - shares	9 Months Ended
	Sep. 30, 2022	Nov. 04, 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	001-36579
Entity Registrant Name	Adverum Biotechnologies, Inc.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	20-5258327
Entity Address, Address Line One	100 Cardinal Way
Entity Address, City or Town	Redwood City
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	94063
City Area Code	650
Local Phone Number	656-9323
Title of 12(b) Security	Common Stock, $0.0001 par value
Trading Symbol	ADVM
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		99,729,025
Amendment Flag	false
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	Q3
Entity Central Index Key	0001501756
Current Fiscal Year End Date	--12-31

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Current assets:
Cash and cash equivalents	$ 84,430	$ 34,195
Short-term investments	118,834	270,993
Lease incentive receivables	0	5,709
Prepaid expenses and other current assets	9,979	6,248
Total current assets	213,243	317,145
Operating lease right-of-use assets	79,882	86,000
Property and equipment, net	36,579	33,060
Restricted cash	2,503	2,503
Deferred rent receivable	0	769
Deposit and other long-term assets	155	250
Total assets	332,362	439,727
Current liabilities:
Accounts payable	846	1,387
Accrued expenses and other current liabilities	16,539	18,047
Lease liability, current portion	11,236	1,886
Total current liabilities	28,621	21,320
Lease liability, net of current portion	94,464	101,108
Other non-current liabilities	940	1,114
Total liabilities	124,025	123,542
Stockholders’ equity:
Preferred stock	0	0
Common stock	10	10
Additional paid-in capital	980,156	964,965
Accumulated other comprehensive loss	(1,953)	(714)
Accumulated deficit	(769,876)	(648,076)
Total stockholders’ equity	208,337	316,185
Total liabilities and stockholders' equity	$ 332,362	$ 439,727

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations and Comprehensive Loss - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Income Statement [Abstract]
License revenue	$ 0	$ 0	$ 0	$ 7,500
Operating expenses:
Research and development	23,849	24,069	77,078	66,657
General and administrative	17,188	14,453	46,117	52,546
Total operating expenses	41,037	38,522	123,195	119,203
Operating loss	(41,037)	(38,522)	(123,195)	(111,703)
Other income, net	923	160	1,450	572
Net loss before income taxes	(40,114)	(38,362)	(121,745)	(111,131)
Income tax provision	(17)	0	(55)	0
Net loss	(40,131)	(38,362)	(121,800)	(111,131)
Other comprehensive loss:
Net unrealized loss on marketable securities	(127)	(55)	(1,189)	(139)
Foreign currency translation adjustment	(30)	(51)	(50)	(123)
Comprehensive loss	$ (40,288)	$ (38,468)	$ (123,039)	$ (111,393)
Net loss per share — basic (in USD per share)	$ (0.40)	$ (0.39)	$ (1.23)	$ (1.13)
Net loss per share — diluted (in USD per share)	$ (0.40)	$ (0.39)	$ (1.23)	$ (1.13)
Weighted-average common shares used to compute net loss per share - basic (in shares)	99,475	98,126	99,027	97,966
Weighted-average common shares used to compute net loss per share - diluted (in shares)	99,475	98,126	99,027	97,966

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Stockholders’ Equity - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive (Loss)/Income	Accumulated Deficit
Beginning balance (in shares) at Dec. 31, 2020		97,549,000
Beginning balance at Dec. 31, 2020	$ 434,347	$ 10	$ 937,134	$ (261)	$ (502,536)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation expense	7,224		7,224
Issuance of common stock, net of issuance costs (in shares)		121,000
Issuance of common stock, net of issuance costs	1,689		1,689
Common stock issued upon exercise of stock options (in shares)		9,000
Common stock issued upon exercise of stock options	51		51
Common stock issued upon release of restricted stock units (in shares)		248,000
Foreign currency translation adjustments	(33)			(33)
Unrealized loss on marketable securities, net	(22)			(22)
Net loss	(28,436)				(28,436)
Ending balance (in shares) at Mar. 31, 2021		97,927,000
Ending balance at Mar. 31, 2021	414,820	$ 10	946,098	(316)	(530,972)
Beginning balance (in shares) at Dec. 31, 2020		97,549,000
Beginning balance at Dec. 31, 2020	434,347	$ 10	937,134	(261)	(502,536)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Foreign currency translation adjustments	(123)
Unrealized loss on marketable securities, net	(139)
Net loss	(111,131)
Ending balance (in shares) at Sep. 30, 2021		98,143,000
Ending balance at Sep. 30, 2021	346,000	$ 10	960,180	(523)	(613,667)
Beginning balance (in shares) at Mar. 31, 2021		97,927,000
Beginning balance at Mar. 31, 2021	414,820	$ 10	946,098	(316)	(530,972)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation expense	8,234		8,234
Issuance of common stock, additional issuance costs	(4)		(4)
Common stock issued upon release of restricted stock units (in shares)		17,000
Common stock issued under employee stock purchase plan (in shares)		176,000
Common stock issued under employee stock purchase plan	526		526
Foreign currency translation adjustments	(39)			(39)
Unrealized loss on marketable securities, net	(62)			(62)
Net loss	(44,333)				(44,333)
Ending balance (in shares) at Jun. 30, 2021		98,120,000
Ending balance at Jun. 30, 2021	379,142	$ 10	954,854	(417)	(575,305)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation expense	5,326		5,326
Common stock issued upon release of restricted stock units (in shares)		23,000
Foreign currency translation adjustments	(51)			(51)
Unrealized loss on marketable securities, net	(55)			(55)
Net loss	(38,362)				(38,362)
Ending balance (in shares) at Sep. 30, 2021		98,143,000
Ending balance at Sep. 30, 2021	346,000	$ 10	960,180	(523)	(613,667)
Beginning balance (in shares) at Dec. 31, 2021		98,381,000
Beginning balance at Dec. 31, 2021	316,185	$ 10	964,965	(714)	(648,076)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation expense	5,381		5,381
Common stock issued upon exercise of stock options (in shares)		15,000
Common stock issued upon exercise of stock options	3		3
Common stock issued upon release of restricted stock units (in shares)		371,000
Foreign currency translation adjustments	14			14
Unrealized loss on marketable securities, net	(723)			(723)
Net loss	(37,908)				(37,908)
Ending balance (in shares) at Mar. 31, 2022		98,767,000
Ending balance at Mar. 31, 2022	282,952	$ 10	970,349	(1,423)	(685,984)
Beginning balance (in shares) at Dec. 31, 2021		98,381,000
Beginning balance at Dec. 31, 2021	$ 316,185	$ 10	964,965	(714)	(648,076)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock issued upon exercise of stock options (in shares)	15,000
Foreign currency translation adjustments	$ (50)
Unrealized loss on marketable securities, net	(1,189)
Net loss	(121,800)
Ending balance (in shares) at Sep. 30, 2022		99,728,000
Ending balance at Sep. 30, 2022	208,337	$ 10	980,156	(1,953)	(769,876)
Beginning balance (in shares) at Mar. 31, 2022		98,767,000
Beginning balance at Mar. 31, 2022	282,952	$ 10	970,349	(1,423)	(685,984)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation expense	4,942		4,942
Common stock issued upon release of restricted stock units (in shares)		5,000
Common stock issued under employee stock purchase plan (in shares)		499,000
Common stock issued under employee stock purchase plan	362		362
Foreign currency translation adjustments	(34)			(34)
Unrealized loss on marketable securities, net	(339)			(339)
Net loss	(43,761)				(43,761)
Ending balance (in shares) at Jun. 30, 2022		99,271,000
Ending balance at Jun. 30, 2022	244,122	$ 10	975,653	(1,796)	(729,745)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation expense	4,503		4,503
Common stock issued upon release of restricted stock units (in shares)		457,000
Foreign currency translation adjustments	(30)			(30)
Unrealized loss on marketable securities, net	(127)			(127)
Net loss	(40,131)				(40,131)
Ending balance (in shares) at Sep. 30, 2022		99,728,000
Ending balance at Sep. 30, 2022	$ 208,337	$ 10	$ 980,156	$ (1,953)	$ (769,876)

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Stockholders Equity (Parenthetical) $ in Thousands	3 Months Ended
	Mar. 31, 2021 USD ($)
Statement of Stockholders' Equity [Abstract]
Stock issuance costs	$ 5

Condensed Consolidated Statem_4

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021
Cash flows from operating activities:
Net loss	$ (121,800)	$ (111,131)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	4,816	3,323
Stock-based compensation expense	14,826	20,784
Amortization of premium and accrued interest on marketable securities	(277)	2,273
Loss on disposal of property and equipment	101	0
Impairment of long-lived assets	2,011	1,072
Other	(1,526)	(132)
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	(3,468)	(3,493)
Other assets	864	(109)
Operating lease right-of-use asset	3,092	2,825
Accounts payable	(543)	(587)
Accrued expenses and other current liabilities	(272)	3,253
Other non-current liabilities	55	0
Lease liability and lease incentive receivable	12,505	(94)
Net cash used in operating activities	(89,616)	(82,016)
Cash flows from investing activities:
Purchases of marketable securities	(81,782)	(328,275)
Maturities of marketable securities	232,899	384,882
Sales of marketable securities	0	8,990
Purchases of property and equipment	(11,631)	(10,771)
Net cash provided by investing activities	139,486	54,826
Cash flows from financing activities:
Proceeds from offerings of common stock, net of issuance costs	0	1,685
Proceeds from issuance of common stock pursuant to option exercises	3	51
Proceeds from employee stock purchase plan	362	526
Repayment of loan	0	(240)
Net cash provided by financing activities	365	2,022
Net increase (decrease) in cash and cash equivalents and restricted cash	50,235	(25,168)
Cash and cash equivalents and restricted cash at beginning of period	36,698	63,423
Cash and cash equivalents and restricted cash at end of period	86,933	38,255
Cash and cash equivalents	84,430	32,971
Restricted cash	2,503	5,284
Cash and cash equivalents and restricted cash at end of period	86,933	38,255
Supplemental schedule of noncash investing and financing information
Right-of-use assets obtained in exchange for lease liability	0	84,005
Remeasurement of operating right-of-use assets	2,842	0
Fixed assets in accounts payable, accrued expenses and other current liabilities	$ 168	$ 2,675

Organization and Basis of Prese

Organization and Basis of Presentation	9 Months Ended
	Sep. 30, 2022
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization and Basis of Presentation	Organization and Basis of Presentation Adverum Biotechnologies, Inc. (the “Company” or “Adverum”) was incorporated in Delaware on July 17, 2006 and is headquartered in Redwood City, California. The Company is a clinical-stage company that aims to establish gene therapy as a new standard of care for a number of highly prevalent ocular diseases. The Company develops gene therapy product candidates intended to provide durable efficacy by inducing sustained expression of a therapeutic protein. The Company has not generated any revenue from the sale of products since its inception. The Company has experienced net losses since its inception and had an accumulated deficit of $769.9 million as of September 30, 2022. The Company expects to incur losses and have negative net cash flows from operating activities as it engages in further research and development activities. As of September 30, 2022, the Company had cash, cash equivalents and short-term investments of $203.3 million, which the Company believes will be sufficient to fund its operations for at least twelve months from the date of issuance of these financial statements. Basis of Presentation — The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles (“U.S. GAAP”) and follow the requirements of the Securities and Exchange Commission (“SEC”) for interim reporting. As permitted under those rules, certain footnotes or other financial information that are normally required by U.S. GAAP can be condensed or omitted. These unaudited condensed consolidated financial statements have been prepared on the same basis as the Company’s annual consolidated financial statements and, in the opinion of management, reflect all adjustments, consisting only of normal recurring adjustments, which are necessary for a fair statement of the Company’s consolidated financial information. The results of operations for the three and nine months ended September 30, 2022 are not necessarily indicative of the results to be expected for the full year or any other future period. The balance sheet as of December 31, 2021 is derived from the audited consolidated financial statements at that date but does not include all of the information required by U.S. GAAP for complete consolidated financial statements. The accompanying unaudited condensed consolidated financial statements and related financial information should be read in conjunction with the audited consolidated financial statements and the related notes thereto included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2021 filed with the SEC.

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 Use of Estimates The accompanying condensed consolidated financial statements have been prepared in accordance with U.S. GAAP. The preparation of the condensed consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, disclosure of contingent liabilities and the reported amounts of expenses in the condensed consolidated financial statements and the accompanying notes. On an ongoing basis, management evaluates its estimates, including those related to clinical trial accruals, fair value of assets and liabilities, impairment of long-lived assets, income taxes, and stock-based compensation. Management bases its estimates on historical experience and on various other market-specific and relevant assumptions that management believes to be reasonable under the circumstances. Actual results could differ from those estimates. Recent Accounting Pronouncements In June 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2016-13, Financial Instruments – Credit Losses: Measurement of Credit Losses on Financial Instruments (“ Topic 326 ”) and also issued subsequent amendments to the initial guidance: ASU 2018-19, ASU 2019-04, ASU 2019-05, and ASU 2019-11. The standard requires that financial assets measured at amortized cost be presented at the net amount expected to be collected. The measurement of expected credit losses is based on historical experience, current conditions, and reasonable and supportable forecasts that affect collectability. Topic 326 also eliminates the concept of “other-than-temporary” impairment when evaluating available-for-sale debt securities and instead focuses on determining whether any impairment is a result of a credit loss or other factors. An entity will recognize an allowance for credit losses on available-for-sale debt securities rather than an other-than-temporary impairment that reduces the cost basis of the investment. Topic 326 will become effective for the Company on January 1, 2023. Early adoption is permitted. The Company does not expect the effect of adoption to be material.

Fair Value Measurements and Fai

Fair Value Measurements and Fair Value of Financial Instruments	9 Months Ended
	Sep. 30, 2022
Fair Value Disclosures [Abstract]
Fair Value Measurements and Fair Value of Financial Instruments	Fair Value Measurements and Fair Value of Financial Instruments The authoritative guidance on the fair value hierarchy for disclosure of fair value measurements is as follows: Level 1 : Quoted prices in active markets for identical assets or liabilities. Level 2 : Observable inputs other than Level 1 prices, such as quoted prices for similar assets or liabilities, quoted prices in markets that are not active, or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities. Level 3 : Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities. The fair value of Level 1 securities is determined using quoted prices in active markets for identical assets. Level 1 securities consist of highly liquid money market funds. Financial assets and liabilities are considered Level 2 when their fair values are 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. U.S. government and agency securities, commercial paper, and corporate bonds are valued primarily using market prices of comparable securities, bid/ask quotes, interest rate yields and prepayment spreads and are included in Level 2. The following is a summary of the Company’s cash equivalents and short-term investments: September 30, 2022 Amortized Cost Basis Unrealized Gains Unrealized Estimated Fair Value (In thousands) Level 1: Money market funds $ 10,074 $ — $ — $ 10,074 Level 2: U.S. government and agency securities 81,323 2 (1,165) 80,160 Commercial paper 99,867 — (294) 99,573 Corporate bonds 2,059 — (49) 2,010 Total cash equivalents and short-term investments 193,323 2 (1,508) 191,817 Less: cash equivalents (72,987) (2) 6 (72,983) Total short-term investments $ 120,336 $ — $ (1,502) $ 118,834 December 31, 2021 Amortized Cost Basis Unrealized Gains Unrealized Estimated Fair Value (In thousands) Level 1: Money market funds $ 10,311 $ — $ — $ 10,311 Level 2: U.S. government and agency securities 62,268 — (218) 62,050 Commercial paper 177,215 1 (61) 177,155 Corporate bonds 47,323 — (39) 47,284 Total cash equivalents and short-term investments 297,117 1 (318) 296,800 Less: cash equivalents (25,808) — 1 (25,807) Total short-term investments $ 271,309 $ 1 $ (317) $ 270,993 As of September 30, 2022, $9.6 million of marketable securities have a remaining maturity between one During the nine months ended September 30, 2022, the Company performed an impairment test to measure certain laboratory equipment at fair value. The assets are measured at fair value using Level 3 inputs on a non-recurring basis as a result of the occurrence of certain triggering events indicating the carrying value of the assets may not be recoverable. Refer to Note 4, Balance Sheet Components for additional information.

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 consists of the following: September 30, 2022 December 31, 2021 (In thousands) Computer equipment and software $ 1,325 $ 1,224 Laboratory equipment 16,368 12,778 Furniture and fixtures 868 1,136 Leasehold improvements 34,336 26,701 Construction in progress 1,076 4,395 Total property and equipment 53,973 46,234 Less accumulated depreciation and amortization (17,394) (13,174) Property and equipment, net $ 36,579 $ 33,060 The Company performed an impairment analysis for certain laboratory equipment assets based on the identification of impairment indicators during the nine months ended September 30, 2022. The analysis determined that the fair value of the assets, which was determined using a market approach, was lower than the carrying value. As a result of the evaluation, an impairment charge of $2.0 million was recognized for the nine months ended September 30, 2022. The assets indicated as impaired were written down to their estimated fair value. Accrued Expenses and Other Current Liabilities Accrued expenses and other current liabilities consist of the following: September 30, 2022 December 31, 2021 (In thousands) Employee compensation $ 8,604 $ 9,209 Accrued nonclinical, clinical and process development costs 6,580 4,953 State income tax payable 301 1,318 Accrued professional services 469 550 Other 585 2,017 Total accrued expenses and other current liabilities $ 16,539 $ 18,047

Leases

Leases	9 Months Ended
	Sep. 30, 2022
Leases [Abstract]
Leases	LeasesSublease income for operating leases is recognized on a straight-line basis over the lease term and is classified as a reduction of rent expense in operating expenses. The difference between sublease income recorded and cash received from the subtenant accrues as a deferred rent receivable. In the three months ended September 30, 2022, the Company reassessed the probability of collection of the deferred rent receivable from the subtenant over the remaining term of a sublease. The Company assessed the collectability to be less than probable and recognized an adjustment to eliminate the deferred rent receivable as a current period adjustment to sublease income, resulting in an increase in general and administrative expenses in the three and nine month periods ended September 30, 2022. The deferred rent receivable as of December 31, 2021 and September 30, 2022 was $0.8 million and zero, respectively. As a result of the adjustment to eliminate the deferred rent receivable, sublease income for the three and nine months ended September 30, 2022 was a negative $4.1 million and a negative $0.8 million, respectively

Equity Incentive Awards

Equity Incentive Awards	9 Months Ended
	Sep. 30, 2022
Share-Based Payment Arrangement [Abstract]
Equity Incentive Awards	Equity Incentive Awards Stock Options The following table summarizes the Company’s option activity and related information: Number of Weighted- Balance at December 31, 2021 13,288 $ 9.34 Options granted 10,592 1.26 Options exercised (15) 0.19 Options forfeited (4,644) 5.42 Balance at September 30, 2022 19,221 $ 5.84 Exercisable as of September 30, 2022 5,302 $ 11.71 Options granted during the nine months ended September 30, 2022 include 2.5 million shares of performance-based non-qualified options with both performance and service vesting conditions. Restricted Stock Units (“RSUs”) The following table summarizes the Company’s RSUs activity and related information: Number of Units Weighted- Outstanding at December 31, 2021 2,126 $ 3.76 Granted 857 1.43 Vested and released (833) 3.40 Forfeited (426) 3.18 Outstanding at September 30, 2022 1,724 $ 2.92 RSUs granted during the nine months ended September 30, 2022 include 0.4 million shares of performance units with both performance and service vesting conditions. Stock-Based Compensation Expense The following table presents, by operating expense, the Company’s stock-based compensation expense: Three Months Ended Nine Months Ended 2022 2021 2022 2021 (In thousands) Research and development $ 1,432 $ 2,207 $ 5,195 $ 7,125 General and administrative 3,071 3,119 9,631 13,659 Total stock-based compensation expense $ 4,503 $ 5,326 $ 14,826 $ 20,784

Net Loss per Share

Net Loss per Share	9 Months Ended
	Sep. 30, 2022
Earnings Per Share [Abstract]
Net Loss per Share	Net Loss per Share Basic net loss per share is calculated by dividing the net loss by the weighted-average number of shares of common stock outstanding for the period. Diluted net loss per share is computed by giving effect to all potential dilutive common stock equivalents outstanding for the period using the treasury stock method. Outstanding stock options, RSUs, rights under the employee stock purchase plan (“ESPP”) and warrants are considered to be common stock equivalents and are only included in the calculation of diluted net loss per share when their effect is dilutive. The following common stock equivalents outstanding at the end of the periods presented were excluded from the calculation of diluted net loss per share for the periods indicated because including them would have had an anti-dilutive effect: September 30, 2022 September 30, 2021 (In thousands) Stock options 19,221 13,859 Restricted stock units 1,724 2,593 ESPP 760 400 21,705 16,852

Restructuring

Restructuring	9 Months Ended
	Sep. 30, 2022
Restructuring and Related Activities [Abstract]
Restructuring	Restructuring In July 2022, the Company implemented a restructuring of operations, including reductions in both headcount and expenses, to prioritize its clinical development of ixoberogene soroparvovec (“Ixo-vec”), formerly referred to as ADVM-022, and focus its pipeline strategy on certain highly prevalent ocular diseases. Under the restructuring plan, the Company reduced its workforce by 75 employees (approximately 37%) as of July 6, 2022. Below is a summary of restructuring costs during the nine months ended September 30, 2022 and accrued restructuring costs as of September 30, 2022 : Severance and Benefits Costs Stock-Based Compensation Total (In thousands) Balance at January 1, 2022 $ — $ — $ — Charges 4,632 53 4,685 Cash payments made (4,539) — (4,539) Non-cash — (53) (53) Balance at September 30, 2022 $ 93 $ — $ 93 In the three and nine months ended September 30, 2022, the Company recorded $4.7 million of restructuring costs, of which $3.7 million was classified as research and development expenses and $1.0 million was classified as general and administrative expenses. Substantially all of the restructuring costs were incurred during the three months ended September 30, 2022, of which $4.5 million were paid. The Company expects the restructuring to be completed in the fourth quarter of 2022.

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 unaudited condensed consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles (“U.S. GAAP”) and follow the requirements of the Securities and Exchange Commission (“SEC”) for interim reporting. As permitted under those rules, certain footnotes or other financial information that are normally required by U.S. GAAP can be condensed or omitted. These unaudited condensed consolidated financial statements have been prepared on the same basis as the Company’s annual consolidated financial statements and, in the opinion of management, reflect all adjustments, consisting only of normal recurring adjustments, which are necessary for a fair statement of the Company’s consolidated financial information. The results of operations for the three and nine months ended September 30, 2022 are not necessarily indicative of the results to be expected for the full year or any other future period. The balance sheet as of December 31, 2021 is derived from the audited consolidated financial statements at that date but does not include all of the information required by U.S. GAAP for complete consolidated financial statements.
Use of Estimates	Use of Estimates The accompanying condensed consolidated financial statements have been prepared in accordance with U.S. GAAP. The preparation of the condensed consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, disclosure of contingent liabilities and the reported amounts of expenses in the condensed consolidated financial statements and the accompanying notes. On an ongoing basis, management evaluates its estimates, including those related to clinical trial accruals, fair value of assets and liabilities, impairment of long-lived assets, income taxes, and stock-based compensation. Management bases its estimates on historical experience and on various other market-specific and relevant assumptions that management believes to be reasonable under the circumstances. Actual results could differ from those estimates.
Recent Accounting Pronouncements	Recent Accounting Pronouncements In June 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2016-13, Financial Instruments – Credit Losses: Measurement of Credit Losses on Financial Instruments (“ Topic 326 ”) and also issued subsequent amendments to the initial guidance: ASU 2018-19, ASU 2019-04, ASU 2019-05, and ASU 2019-11. The standard requires that financial assets measured at amortized cost be presented at the net amount expected to be collected. The measurement of expected credit losses is based on historical experience, current conditions, and reasonable and supportable forecasts that affect collectability. Topic 326 also eliminates the concept of “other-than-temporary” impairment when evaluating available-for-sale debt securities and instead focuses on determining whether any impairment is a result of a credit loss or other factors. An entity will recognize an allowance for credit losses on available-for-sale debt securities rather than an other-than-temporary impairment that reduces the cost basis of the investment. Topic 326 will become effective for the Company on January 1, 2023. Early adoption is permitted. The Company does not expect the effect of adoption to be material.

Fair Value Measurements and F_2

Fair Value Measurements and Fair Value of Financial Instruments (Tables)	9 Months Ended
	Sep. 30, 2022
Fair Value Disclosures [Abstract]
Schedule of Cash Equivalents and Short-term Investments	The following is a summary of the Company’s cash equivalents and short-term investments: September 30, 2022 Amortized Cost Basis Unrealized Gains Unrealized Estimated Fair Value (In thousands) Level 1: Money market funds $ 10,074 $ — $ — $ 10,074 Level 2: U.S. government and agency securities 81,323 2 (1,165) 80,160 Commercial paper 99,867 — (294) 99,573 Corporate bonds 2,059 — (49) 2,010 Total cash equivalents and short-term investments 193,323 2 (1,508) 191,817 Less: cash equivalents (72,987) (2) 6 (72,983) Total short-term investments $ 120,336 $ — $ (1,502) $ 118,834 December 31, 2021 Amortized Cost Basis Unrealized Gains Unrealized Estimated Fair Value (In thousands) Level 1: Money market funds $ 10,311 $ — $ — $ 10,311 Level 2: U.S. government and agency securities 62,268 — (218) 62,050 Commercial paper 177,215 1 (61) 177,155 Corporate bonds 47,323 — (39) 47,284 Total cash equivalents and short-term investments 297,117 1 (318) 296,800 Less: cash equivalents (25,808) — 1 (25,807) Total short-term investments $ 271,309 $ 1 $ (317) $ 270,993

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 consists of the following: September 30, 2022 December 31, 2021 (In thousands) Computer equipment and software $ 1,325 $ 1,224 Laboratory equipment 16,368 12,778 Furniture and fixtures 868 1,136 Leasehold improvements 34,336 26,701 Construction in progress 1,076 4,395 Total property and equipment 53,973 46,234 Less accumulated depreciation and amortization (17,394) (13,174) Property and equipment, net $ 36,579 $ 33,060
Schedule of Accrued Expenses and Other Current Liabilities	Accrued expenses and other current liabilities consist of the following: September 30, 2022 December 31, 2021 (In thousands) Employee compensation $ 8,604 $ 9,209 Accrued nonclinical, clinical and process development costs 6,580 4,953 State income tax payable 301 1,318 Accrued professional services 469 550 Other 585 2,017 Total accrued expenses and other current liabilities $ 16,539 $ 18,047

Equity Incentive Awards (Tables

Equity Incentive Awards (Tables)	9 Months Ended
	Sep. 30, 2022
Share-Based Payment Arrangement [Abstract]
Schedule of Stock Options Activity	The following table summarizes the Company’s option activity and related information: Number of Weighted- Balance at December 31, 2021 13,288 $ 9.34 Options granted 10,592 1.26 Options exercised (15) 0.19 Options forfeited (4,644) 5.42 Balance at September 30, 2022 19,221 $ 5.84 Exercisable as of September 30, 2022 5,302 $ 11.71
Schedule of Restricted Stock Units Activity	The following table summarizes the Company’s RSUs activity and related information: Number of Units Weighted- Outstanding at December 31, 2021 2,126 $ 3.76 Granted 857 1.43 Vested and released (833) 3.40 Forfeited (426) 3.18 Outstanding at September 30, 2022 1,724 $ 2.92
Schedule of Stock-Based Compensation Expense	The following table presents, by operating expense, the Company’s stock-based compensation expense: Three Months Ended Nine Months Ended 2022 2021 2022 2021 (In thousands) Research and development $ 1,432 $ 2,207 $ 5,195 $ 7,125 General and administrative 3,071 3,119 9,631 13,659 Total stock-based compensation expense $ 4,503 $ 5,326 $ 14,826 $ 20,784

Net Loss per Share (Tables)

Net Loss per Share (Tables)	9 Months Ended
	Sep. 30, 2022
Earnings Per Share [Abstract]
Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share	The following common stock equivalents outstanding at the end of the periods presented were excluded from the calculation of diluted net loss per share for the periods indicated because including them would have had an anti-dilutive effect: September 30, 2022 September 30, 2021 (In thousands) Stock options 19,221 13,859 Restricted stock units 1,724 2,593 ESPP 760 400 21,705 16,852

Restructuring (Tables)

Restructuring (Tables)	9 Months Ended
	Sep. 30, 2022
Restructuring and Related Activities [Abstract]
Schedule of Restructuring Cost	Below is a summary of restructuring costs during the nine months ended September 30, 2022 and accrued restructuring costs as of September 30, 2022 : Severance and Benefits Costs Stock-Based Compensation Total (In thousands) Balance at January 1, 2022 $ — $ — $ — Charges 4,632 53 4,685 Cash payments made (4,539) — (4,539) Non-cash — (53) (53) Balance at September 30, 2022 $ 93 $ — $ 93

Organization and Basis of Pre_2

Organization and Basis of Presentation (Detail) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Accumulated deficit	$ 769,876	$ 648,076
Cash, cash equivalents, and short-term investments	$ 203,300

Fair Value Measurements and F_3

Fair Value Measurements and Fair Value of Financial Instruments - Summary of Cash Equivalents and Short-term Investments (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Debt Securities, Available-for-sale [Line Items]
Amortized Cost Basis	$ 120,336	$ 271,309
Unrealized Gains	0	1
Unrealized Losses	(1,502)	(317)
Estimated Fair Value	118,834	270,993
Less: cash equivalents, amortized cost basis	(72,987)	(25,808)
Less: cash equivalents, unrealized gains	(2)	0
Less: cash equivalents, unrealized losses	6	1
Less: cash equivalents, estimated fair value	(72,983)	(25,807)
Money market funds | Level 1:
Debt Securities, Available-for-sale [Line Items]
Amortized Cost Basis	10,074	10,311
Unrealized Gains	0	0
Unrealized Losses	0	0
Estimated Fair Value	10,074	10,311
U.S. government and agency securities | Level 2:
Debt Securities, Available-for-sale [Line Items]
Amortized Cost Basis	81,323	62,268
Unrealized Gains	2	0
Unrealized Losses	(1,165)	(218)
Estimated Fair Value	80,160	62,050
Commercial paper | Level 2:
Debt Securities, Available-for-sale [Line Items]
Amortized Cost Basis	99,867	177,215
Unrealized Gains	0	1
Unrealized Losses	(294)	(61)
Estimated Fair Value	99,573	177,155
Corporate bonds | Level 2:
Debt Securities, Available-for-sale [Line Items]
Amortized Cost Basis	2,059	47,323
Unrealized Gains	0	0
Unrealized Losses	(49)	(39)
Estimated Fair Value	2,010	47,284
Total cash equivalents and short-term investments
Debt Securities, Available-for-sale [Line Items]
Amortized Cost Basis	193,323	297,117
Unrealized Gains	2	1
Unrealized Losses	(1,508)	(318)
Estimated Fair Value	$ 191,817	$ 296,800

Fair Value Measurements and F_4

Fair Value Measurements and Fair Value of Financial Instruments - Additional Information (Details)	Sep. 30, 2022 USD ($)
Debt Securities, Available-for-sale [Line Items]
Marketable securities	$ 9,600,000
Marketable securities in an unrealized loss	167,900,000
Marketable securities other-than-temporarily impaired	$ 0
Minimum
Debt Securities, Available-for-sale [Line Items]
Marketable securities term (in years)	1 year
Maximum
Debt Securities, Available-for-sale [Line Items]
Marketable securities term (in years)	2 years

Balance Sheet Components - Sche

Balance Sheet Components - Schedule of Property and Equipment, Net (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2022	Dec. 31, 2021
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 53,973	$ 46,234
Less accumulated depreciation and amortization	(17,394)	(13,174)
Property and equipment, net	36,579	33,060
Asset impairment charge	2,000
Computer equipment and software
Property, Plant and Equipment [Line Items]
Total property and equipment	1,325	1,224
Laboratory equipment
Property, Plant and Equipment [Line Items]
Total property and equipment	16,368	12,778
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Total property and equipment	868	1,136
Leasehold improvements
Property, Plant and Equipment [Line Items]
Total property and equipment	34,336	26,701
Construction in progress
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 1,076	$ 4,395

Balance Sheet Components - Sc_2

Balance Sheet Components - Schedule of Accrued Expenses and Other Current Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Balance Sheet Related Disclosures [Abstract]
Employee compensation	$ 8,604	$ 9,209
Accrued nonclinical, clinical and process development costs	6,580	4,953
State income tax payable	301	1,318
Accrued professional services	469	550
Other	585	2,017
Total accrued expenses and other current liabilities	$ 16,539	$ 18,047

Leases - Additional Information

Leases - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2022	Sep. 30, 2022	Dec. 31, 2021
Leases [Abstract]
Deferred rent receivable	$ 0	$ 0	$ 769
Negative sublease income	$ 4,100	$ 800

Equity Incentive Awards - Summa

Equity Incentive Awards - Summary of Stock Options Activity (Details) shares in Thousands	9 Months Ended
	Sep. 30, 2022 $ / shares shares
Number of Options (in thousands)
Beginning balance (in shares) | shares	13,288
Options granted (in shares) | shares	10,592
Options exercised (in shares) | shares	(15)
Options forfeited (in shares) | shares	(4,644)
Ending balance (in shares) | shares	19,221
Exercisable (in shares) | shares	5,302
Weighted- Average Grant- Date Fair Value
Beginning balance (in USD per share) | $ / shares	$ 9.34
Options granted (in USD per share) | $ / shares	1.26
Options exercised (in USD per share) | $ / shares	0.19
Options forfeited (in USD per share) | $ / shares	5.42
Ending balance (in USD per share) | $ / shares	5.84
Exercisable (in USD per share) | $ / shares	$ 11.71

Equity Incentive Awards - Addit

Equity Incentive Awards - Additional Information (Details) shares in Thousands	9 Months Ended
	Sep. 30, 2022 shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options granted (in shares)	10,592
Performance Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options granted (in shares)	2,500
RSUs granted (in shares)	400

Equity Incentive Awards - Sum_2

Equity Incentive Awards - Summary of Restricted Stock Units Activity (Details) - Restricted stock units shares in Thousands	9 Months Ended
	Sep. 30, 2022 $ / shares shares
Number of Units (in thousands)
Beginning balance (in shares) | shares	2,126
Granted (in shares) | shares	857
Vested and released (in shares) | shares	(833)
Forfeited (in shares) | shares	(426)
Ending balance (in shares) | shares	1,724
Weighted- Average Grant- Date Fair Value
Beginning balance (in USD per share) | $ / shares	$ 3.76
Granted (in USD per share) | $ / shares	1.43
Vested and released (in USD per share) | $ / shares	3.40
Forfeited (in USD per share) | $ / shares	3.18
Ending balance (in USD per share) | $ / shares	$ 2.92

Equity Incentive Awards - Sum_3

Equity Incentive Awards - Summary of Stock-Based Compensation Expense (Details) - 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, Expensed and Capitalized, Amount [Line Items]
Total stock-based compensation expense	$ 4,503	$ 5,326	$ 14,826	$ 20,784
Research and development
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total stock-based compensation expense	1,432	2,207	5,195	7,125
General and administrative
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total stock-based compensation expense	$ 3,071	$ 3,119	$ 9,631	$ 13,659

Net Loss per Share - Schedule o

Net Loss per Share - Schedule of Common Stock Equivalents Outstanding (Details) - shares shares in Thousands	9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from net loss per share (in shares)	21,705	16,852
Stock options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from net loss per share (in shares)	19,221	13,859
Restricted stock units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from net loss per share (in shares)	1,724	2,593
ESPP
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from net loss per share (in shares)	760	400

Restructuring - Additional Info

Restructuring - Additional Information (Details) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2022 USD ($)	Sep. 30, 2022 USD ($)	Jul. 06, 2022 employee
Restructuring Cost and Reserve [Line Items]
Number of employees | employee			75
Number of employees percentage			37%
Restructuring charges		$ 4,685
Restructuring cost paid	$ 4,500	4,539
Research and Development Expense
Restructuring Cost and Reserve [Line Items]
Restructuring charges		3,700
General and Administrative Expense
Restructuring Cost and Reserve [Line Items]
Restructuring charges		$ 1,000

Restructuring - Schedule of Res

Restructuring - Schedule of Restructuring Cost (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2022	Sep. 30, 2022
Restructuring Reserve [Roll Forward]
Restructuring cost, beginning balance		$ 0
Charges		4,685
Cash payments made	$ (4,500)	(4,539)
Non-cash		(53)
Restructuring cost, ending balance	93	93
Severance and Benefits Costs
Restructuring Reserve [Roll Forward]
Restructuring cost, beginning balance		0
Charges		4,632
Cash payments made		(4,539)
Non-cash		0
Restructuring cost, ending balance	93	93
Stock-Based Compensation
Restructuring Reserve [Roll Forward]
Restructuring cost, beginning balance		0
Charges		53
Cash payments made		0
Non-cash		(53)
Restructuring cost, ending balance	$ 0	$ 0