Adverum Biotechnologies (ADVM) 10-Q 12 May 22 2022 Q1 Quarterly report Financial data

Cover Page

Cover Page - shares	3 Months Ended
	Mar. 31, 2022	May 06, 2022
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 31, 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		98,770,349
Amendment Flag	false
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	Q1
Entity Central Index Key	0001501756
Current Fiscal Year End Date	--12-31

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Current assets:
Cash and cash equivalents	$ 89,652	$ 34,195
Short-term investments	181,403	270,993
Lease incentive receivables	0	5,709
Prepaid expenses and other current assets	9,062	6,248
Total current assets	280,117	317,145
Operating lease right-of-use assets	84,874	86,000
Property and equipment, net	37,223	33,060
Restricted cash	2,503	2,503
Deferred rent receivable	2,457	769
Deposit and other long-term assets	220	250
Total assets	407,394	439,727
Current liabilities:
Accounts payable	3,245	1,387
Accrued expenses and other current liabilities	17,633	18,047
Lease liability, current portion	2,359	1,886
Total current liabilities	23,237	21,320
Lease liability, net of current portion	100,178	101,108
Other non-current liabilities	1,027	1,114
Total liabilities	124,442	123,542
Stockholders’ equity:
Preferred stock	0	0
Common stock	10	10
Additional paid-in capital	970,349	964,965
Accumulated other comprehensive loss	(1,423)	(714)
Accumulated deficit	(685,984)	(648,076)
Total stockholders’ equity	282,952	316,185
Total liabilities and stockholders' equity	$ 407,394	$ 439,727

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations and Comprehensive Loss - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Income Statement [Abstract]
License revenue	$ 0	$ 7,500
Operating expenses:
Research and development	22,964	19,980
General and administrative	15,169	16,163
Total operating expenses	38,133	36,143
Operating loss	(38,133)	(28,643)
Other income, net	244	207
Net loss before income taxes	(37,889)	(28,436)
Income tax provision	(19)	0
Net loss	(37,908)	(28,436)
Other comprehensive income (loss):
Net unrealized loss on marketable securities	(723)	(22)
Foreign currency translation adjustment	14	(33)
Comprehensive loss	$ (38,617)	$ (28,491)
Net loss per share — basic (in USD per share)	$ (0.38)	$ (0.29)
Net loss per share — diluted (in USD per share)	$ (0.38)	$ (0.29)
Weighted-average common shares used to compute net loss per share - basic (in shares)	98,596	97,750
Weighted-average common shares used to compute net loss per share - diluted (in shares)	98,596	97,750

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, 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	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
Ending balance at Mar. 31, 2022	$ 282,952	$ 10	$ 970,349	$ (1,423)	$ (685,984)

Condensed Consolidated Statem_3

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

Condensed Consolidated Statem_4

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Cash flows from operating activities:
Net loss	$ (37,908)	$ (28,436)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	1,425	1,166
Stock-based compensation expense	5,381	7,224
Amortization of premium and accrued interest on marketable securities	212	855
Other	(92)	(42)
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	(2,916)	(1,279)
Other assets	(1,658)	(464)
Operating lease right-of-use asset	1,126	332
Accounts payable	1,437	(763)
Accrued expenses and other current liabilities	(1,207)	(396)
Other non-current liabilities	19	0
Lease liability and lease incentive receivable	5,252	(502)
Net cash used in operating activities	(28,929)	(22,305)
Cash flows from investing activities:
Purchases of marketable securities	(29,750)	(82,667)
Maturities of marketable securities	118,507	90,650
Purchases of property and equipment	(4,374)	(1,404)
Net cash provided by investing activities	84,383	6,579
Cash flows from financing activities:
Proceeds from offerings of common stock, net of issuance costs	0	1,694
Proceeds from issuance of common stock pursuant to option exercises	3	51
Repayment of loan	0	(240)
Net cash provided by financing activities	3	1,505
Net increase (decrease) in cash and cash equivalents and restricted cash	55,457	(14,221)
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	92,155	49,202
Cash and cash equivalents	89,652	45,422
Restricted cash	2,503	3,780
Cash and cash equivalents and restricted cash at end of period	92,155	49,202
Supplemental schedule of noncash investing and financing information
Fixed assets in accounts payable, accrued expenses and other current liabilities	$ 2,616	$ 805

Organization and Basis of Prese

Organization and Basis of Presentation	3 Months Ended
	Mar. 31, 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 gene therapy company targeting unmet medical needs in ocular and rare 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 $686.0 million as of March 31, 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 March 31, 2022, the Company had cash, cash equivalents and short-term investments of $271.1 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 months ended March 31, 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	3 Months Ended
	Mar. 31, 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 is currently evaluating the impact of adopting Topic 326, but does not expect the effect of adoption to be material.

Fair Value Measurements and Fai

Fair Value Measurements and Fair Value of Financial Instruments	3 Months Ended
	Mar. 31, 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 bond 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: March 31, 2022 Amortized Cost Basis Unrealized Gains Unrealized Estimated Fair Value (In thousands) Level 1: Money market funds $ 607 $ — $ — $ 607 Level 2: U.S. government and agency securities 62,209 — (811) 61,398 Commercial paper 181,168 1 (179) 180,990 Corporate bonds 23,197 7 (58) 23,146 Total cash equivalents and short-term investments 267,181 8 (1,048) 266,141 Less: cash equivalents (84,741) (1) 4 (84,738) Total short-term investments $ 182,440 $ 7 $ (1,044) $ 181,403 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 one

Balance Sheet Components

Balance Sheet Components	3 Months Ended
	Mar. 31, 2022
Balance Sheet Related Disclosures [Abstract]
Balance Sheet Components	Balance Sheet Components Property and Equipment, Net Property and equipment, net consists of the following: March 31, 2022 December 31, 2021 (In thousands) Computer equipment and software $ 1,234 $ 1,224 Laboratory equipment 14,500 12,778 Furniture and fixtures 1,136 1,136 Leasehold improvements 26,696 26,701 Construction in progress 8,256 4,395 Total property and equipment 51,822 46,234 Less accumulated depreciation and amortization (14,599) (13,174) Property and equipment, net $ 37,223 $ 33,060 Accrued Expenses and Other Current Liabilities Accrued expenses and other current liabilities consist of the following: March 31, 2022 December 31, 2021 (In thousands) Employee compensation $ 7,172 $ 9,209 Accrued nonclinical, clinical and process development costs 5,246 4,953 State income tax payable 1,432 1,318 Accrued professional services 1,067 550 Other 2,716 2,017 Total accrued expenses and other current liabilities $ 17,633 $ 18,047

Equity Incentive Awards

Equity Incentive Awards	3 Months Ended
	Mar. 31, 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 5,735 1.40 Options exercised (15) 0.19 Options forfeited (2,837) 6.60 Balance at March 31, 2022 16,171 $ 7.01 Exercisable as of March 31, 2022 3,921 $ 12.95 Options granted during the three months ended March 31, 2022 include 0.9 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 858 1.43 Vested and released (371) 4.62 Forfeited (91) 3.83 Outstanding at March 31, 2022 2,522 $ 2.84 RSUs granted during the three months ended March 31, 2022 include 0.2 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 2022 2021 (In thousands) Research and development $ 1,933 $ 2,339 General and administrative 3,448 4,885 Total stock-based compensation expense $ 5,381 $ 7,224

Net Loss per Share

Net Loss per Share	3 Months Ended
	Mar. 31, 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: March 31, 2022 March 31, 2021 (In thousands) Stock options 16,171 13,349 Restricted stock units 2,522 672 ESPP 887 86 19,580 14,107

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 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 months ended March 31, 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 is currently evaluating the impact of adopting Topic 326, but 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)	3 Months Ended
	Mar. 31, 2022
Fair Value Disclosures [Abstract]
Summary of Cash Equivalents and Short-term Investments	The following is a summary of the Company’s cash equivalents and short-term investments: March 31, 2022 Amortized Cost Basis Unrealized Gains Unrealized Estimated Fair Value (In thousands) Level 1: Money market funds $ 607 $ — $ — $ 607 Level 2: U.S. government and agency securities 62,209 — (811) 61,398 Commercial paper 181,168 1 (179) 180,990 Corporate bonds 23,197 7 (58) 23,146 Total cash equivalents and short-term investments 267,181 8 (1,048) 266,141 Less: cash equivalents (84,741) (1) 4 (84,738) Total short-term investments $ 182,440 $ 7 $ (1,044) $ 181,403 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)	3 Months Ended
	Mar. 31, 2022
Balance Sheet Related Disclosures [Abstract]
Schedule of Property and Equipment, Net	Property and equipment, net consists of the following: March 31, 2022 December 31, 2021 (In thousands) Computer equipment and software $ 1,234 $ 1,224 Laboratory equipment 14,500 12,778 Furniture and fixtures 1,136 1,136 Leasehold improvements 26,696 26,701 Construction in progress 8,256 4,395 Total property and equipment 51,822 46,234 Less accumulated depreciation and amortization (14,599) (13,174) Property and equipment, net $ 37,223 $ 33,060
Schedule of Accrued Expenses and Other Current Liabilities	Accrued expenses and other current liabilities consist of the following: March 31, 2022 December 31, 2021 (In thousands) Employee compensation $ 7,172 $ 9,209 Accrued nonclinical, clinical and process development costs 5,246 4,953 State income tax payable 1,432 1,318 Accrued professional services 1,067 550 Other 2,716 2,017 Total accrued expenses and other current liabilities $ 17,633 $ 18,047

Equity Incentive Awards (Tables

Equity Incentive Awards (Tables)	3 Months Ended
	Mar. 31, 2022
Share-based Payment Arrangement [Abstract]
Summary 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 5,735 1.40 Options exercised (15) 0.19 Options forfeited (2,837) 6.60 Balance at March 31, 2022 16,171 $ 7.01 Exercisable as of March 31, 2022 3,921 $ 12.95
Summary 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 858 1.43 Vested and released (371) 4.62 Forfeited (91) 3.83 Outstanding at March 31, 2022 2,522 $ 2.84
Stock-Based Compensation Expense	The following table presents, by operating expense, the Company’s stock-based compensation expense: Three Months Ended 2022 2021 (In thousands) Research and development $ 1,933 $ 2,339 General and administrative 3,448 4,885 Total stock-based compensation expense $ 5,381 $ 7,224

Net Loss per Share (Tables)

Net Loss per Share (Tables)	3 Months Ended
	Mar. 31, 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: March 31, 2022 March 31, 2021 (In thousands) Stock options 16,171 13,349 Restricted stock units 2,522 672 ESPP 887 86 19,580 14,107

Organization and Basis of Pre_2

Organization and Basis of Presentation (Detail) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Accumulated deficit	$ (685,984)	$ (648,076)
Cash, cash equivalents, and short-term investments	$ 271,100

Fair Value Measurements and F_3

Fair Value Measurements and Fair Value of Financial Instruments - Summary of Cash Equivalents and Short-term Investments (Detail) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Debt Securities, Available-for-sale [Line Items]
Amortized Cost Basis	$ 182,440	$ 271,309
Unrealized Gains	7	1
Unrealized Losses	(1,044)	(317)
Estimated Fair Value	181,403	270,993
Less: cash equivalents, amortized cost basis	(84,741)	(25,808)
Less: cash equivalents, unrealized gains	(1)	0
Less: cash equivalents, unrealized losses	4	1
Less: cash equivalents, estimated fair value	(84,738)	(25,807)
Money market funds | Level 1
Debt Securities, Available-for-sale [Line Items]
Amortized Cost Basis	607	10,311
Unrealized Gains	0	0
Unrealized Losses	0	0
Estimated Fair Value	607	10,311
U.S. government and agency securities | Level 2
Debt Securities, Available-for-sale [Line Items]
Amortized Cost Basis	62,209	62,268
Unrealized Gains	0	0
Unrealized Losses	(811)	(218)
Estimated Fair Value	61,398	62,050
Commercial paper | Level 2
Debt Securities, Available-for-sale [Line Items]
Amortized Cost Basis	181,168	177,215
Unrealized Gains	1	1
Unrealized Losses	(179)	(61)
Estimated Fair Value	180,990	177,155
Corporate Bond Securities | Level 2
Debt Securities, Available-for-sale [Line Items]
Amortized Cost Basis	23,197	47,323
Unrealized Gains	7	0
Unrealized Losses	(58)	(39)
Estimated Fair Value	23,146	47,284
Total cash equivalents and short-term investments
Debt Securities, Available-for-sale [Line Items]
Amortized Cost Basis	267,181	297,117
Unrealized Gains	8	1
Unrealized Losses	(1,048)	(318)
Estimated Fair Value	$ 266,141	$ 296,800

Fair Value Measurements and F_4

Fair Value Measurements and Fair Value of Financial Instruments - Additional Information (Detail)	Mar. 31, 2022USD ($)
Debt Securities, Available-for-sale [Line Items]
Marketable securities	$ 38,500,000
Marketable securities other-than-temporarily impaired	$ 0
Minimum
Debt Securities, Available-for-sale [Line Items]
Marketable securities term	1 year
Maximum
Debt Securities, Available-for-sale [Line Items]
Marketable securities term	2 years

Balance Sheet Components - Sche

Balance Sheet Components - Schedule of Property and Equipment, Net (Detail) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 51,822	$ 46,234
Less accumulated depreciation and amortization	(14,599)	(13,174)
Property and equipment, net	37,223	33,060
Computer equipment and software
Property, Plant and Equipment [Line Items]
Total property and equipment	1,234	1,224
Laboratory equipment
Property, Plant and Equipment [Line Items]
Total property and equipment	14,500	12,778
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Total property and equipment	1,136	1,136
Leasehold improvements
Property, Plant and Equipment [Line Items]
Total property and equipment	26,696	26,701
Construction in progress
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 8,256	$ 4,395

Balance Sheet Components - Sc_2

Balance Sheet Components - Schedule of Accrued Expenses and Other Current Liabilities (Detail) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Balance Sheet Related Disclosures [Abstract]
Employee compensation	$ 7,172	$ 9,209
Accrued nonclinical, clinical and process development costs	5,246	4,953
State income tax payable	1,432	1,318
Accrued professional services	1,067	550
Other	2,716	2,017
Total accrued expenses and other current liabilities	$ 17,633	$ 18,047

Equity Incentive Awards - Summa

Equity Incentive Awards - Summary of Stock Options Activity (Detail) shares in Thousands	3 Months Ended
	Mar. 31, 2022$ / sharesshares
Number of Options (in thousands)
Beginning balance (in shares) | shares	13,288
Options granted (in shares) | shares	5,735
Options exercised (in shares) | shares	(15)
Options forfeited (in shares) | shares	(2,837)
Ending balance (in shares) | shares	16,171
Exercisable (in shares) | shares	3,921
Weighted- Average Grant- Date Fair Value
Beginning balance (in USD per share) | $ / shares	$ 9.34
Options granted (in USD per share) | $ / shares	1.40
Options exercised (in USD per share) | $ / shares	0.19
Options forfeited (in USD per share) | $ / shares	6.60
Ending balance (in USD per share) | $ / shares	7.01
Exercisable (in USD per share) | $ / shares	$ 12.95

Equity Incentive Awards - Addit

Equity Incentive Awards - Additional Information (Detail) shares in Thousands	3 Months Ended
	Mar. 31, 2022shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options granted (in shares)	5,735
Performance Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options granted (in shares)	900
RSUs granted (in shares)	200

Equity Incentive Awards - Sum_2

Equity Incentive Awards - Summary of Restricted Stock Units Activity (Detail) - Restricted stock units shares in Thousands	3 Months Ended
	Mar. 31, 2022$ / sharesshares
Number of Units (in thousands)
Beginning balance (in shares) | shares	2,126
Granted (in shares) | shares	858
Vested and released (in shares) | shares	(371)
Forfeited (in shares) | shares	(91)
Ending balance (in shares) | shares	2,522
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	4.62
Forfeited (in USD per share) | $ / shares	3.83
Ending balance (in USD per share) | $ / shares	$ 2.84

Equity Incentive Awards - Stock

Equity Incentive Awards - Stock-Based Compensation Expense (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total stock-based compensation expense	$ 5,381	$ 7,224
Research and development
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total stock-based compensation expense	1,933	2,339
General and administrative
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total stock-based compensation expense	$ 3,448	$ 4,885

Net Loss per Share - Schedule o

Net Loss per Share - Schedule of Common Stock Equivalents Outstanding (Detail) - shares shares in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from net loss per share (in shares)	19,580	14,107
Stock options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from net loss per share (in shares)	16,171	13,349
Restricted stock units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from net loss per share (in shares)	2,522	672
ESPP
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from net loss per share (in shares)	887	86