Atea Pharmaceuticals (AVIR) 10-Q 14 May 24 2024 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2024	May 13, 2024
Document Information [Line Items]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2024
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	Q1
Trading Symbol	AVIR
Entity Registrant Name	Atea Pharmaceuticals, Inc.
Entity Central Index Key	0001593899
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Common Stock, Shares Outstanding		84,223,100
Entity Current Reporting Status	Yes
Entity Shell Company	false
Entity File Number	001-39661
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	46-0574869
Entity Address, Address Line One	225 Franklin Street
Entity Address, Address Line Two	Suite 2100
Entity Address, City or Town	Boston
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	02110
City Area Code	857
Local Phone Number	284-8891
Entity Interactive Data Current	Yes
Title of 12(b) Security	Common Stock, $0.001 par value per share
Security Exchange Name	NASDAQ
Document Quarterly Report	true
Document Transition Report	false

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Current assets
Cash and cash equivalents	$ 160,910	$ 143,823
Marketable securities	380,581	434,283
Prepaid expenses and other current assets	7,273	12,349
Total current assets	548,764	590,455
Property and equipment, net	1,185	1,289
Other assets	1,396	1,396
Operating lease right-of-use assets, net	1,684	1,828
Total assets	553,029	594,968
Current liabilities
Accounts payable	21,137	4,252
Accrued expenses and other current liabilities	19,405	27,364
Current portion of operating lease liabilities	769	760
Total current liabilities	41,311	32,376
Operating lease liabilities	1,445	1,642
Income taxes payable	5,902	5,758
Total liabilities	48,658	39,776
Commitments and contingencies (see Note 12)
Stockholders’ equity:
Preferred stock, $0.001 par value per share; 10,000,000 shares authorized; no shares issued and outstanding
Common stock, $0.001 par value; 300,000,000 shares authorized; 84,223,100 and 83,435,513 shares issued and outstanding as of March 31, 2024 and December 31, 2023, respectively	84	83
Additional paid-in capital	763,472	750,737
Accumulated other comprehensive gain (loss)	(181)	207
Accumulated deficit	(259,004)	(195,835)
Total stockholders’ equity	504,371	555,192
Total liabilities and stockholders’ equity	$ 553,029	$ 594,968

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) (Unaudited) - $ / shares	Mar. 31, 2024	Dec. 31, 2023
Statement of Financial Position [Abstract]
Preferred stock, par value	$ 0.001	$ 0.001
Preferred stock, shares authorized	10,000,000	10,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized	300,000,000	300,000,000
Common stock, shares issued	84,223,100	83,435,513
Common stock, shares outstanding	84,223,100	83,435,513

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations and Comprehensive Income (Loss) (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Operating expenses:
Research and development	$ 57,575	$ 28,954
General and administrative	12,231	12,615
Total operating expenses	69,806	41,569
Loss from operations	(69,806)	(41,569)
Interest income and other, net	6,868	6,299
Loss before income taxes	(62,938)	(35,270)
Income tax expense	(231)	(197)
Net loss	(63,169)	(35,467)
Other comprehensive loss
Unrealized gain (loss) on available-for-sale investments	(388)	377
Comprehensive loss	$ (63,557)	$ (35,090)
Net loss per share - basic and diluted
Basic	$ (0.75)	$ (0.43)
Diluted	$ (0.75)	$ (0.43)
Weighted-average number of common shares - basic and diluted
Basic	83,916,193	83,332,397
Diluted	83,916,193	83,332,397

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Stockholders' Equity (Unaudited) - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Gain (Loss)	Retained Earnings (Accumulated Deficit)
Balance at Dec. 31, 2022	$ 640,572	$ 83	$ 701,052	$ (684)	$ (59,879)
Balance, shares at Dec. 31, 2022		83,287,639
Issuance upon vesting of restricted stock units, shares		53,935
Issuance of common stock under employee stock purchase plan	165		165
Issuance of common stock under employee stock purchase plan, shares		57,803
Stock-based compensation expense	12,535		12,535
Other comprehensive income (loss)	377			377
Net loss	(35,467)				(35,467)
Balance at Mar. 31, 2023	618,182	$ 83	713,752	(307)	(95,346)
Balance, shares at Mar. 31, 2023		83,399,377
Balance at Dec. 31, 2023	555,192	$ 83	750,737	207	(195,835)
Balance, shares at Dec. 31, 2023		83,435,513
Issuance upon vesting of restricted stock units		$ 1	(1)
Issuance upon vesting of restricted stock units, shares		729,032
Issuance of common stock under employee stock purchase plan	150		150
Issuance of common stock under employee stock purchase plan, shares		58,555
Stock-based compensation expense	12,586		12,586
Other comprehensive income (loss)	(388)			(388)
Net loss	(63,169)				(63,169)
Balance at Mar. 31, 2024	$ 504,371	$ 84	$ 763,472	$ (181)	$ (259,004)
Balance, shares at Mar. 31, 2024		84,223,100

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Cash flows from operating activities
Net loss	$ (63,169)	$ (35,467)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation expense	12,586	12,535
Depreciation and amortization expense	104	104
Accretion of premium and discounts on marketable securities	(3,488)	(3,087)
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	5,076	2,311
Other assets		(197)
Accounts payable	16,885	(1,851)
Accrued expenses and other liabilities	(7,815)	(4,157)
Operating lease liabilities	(44)	(41)
Net cash used in operating activities	(39,865)	(29,850)
Cash flows from investing activities
Purchases of marketable securities	(167,196)	(156,626)
Sales and maturities of marketable securities	223,998	181,106
Net cash provided by investing activities	56,802	24,480
Cash flows from financing activities
Proceeds from issuance of common stock under ESPP	150	165
Net cash provided by financing activities	150	165
Net increase (decrease) in cash, cash equivalents and restricted cash	17,087	(5,205)
Cash, cash equivalents and restricted cash at the beginning of period	143,823	188,658
Cash, cash equivalents and restricted cash at the end of period	160,910	183,453
Cash, cash equivalents and restricted cash at the end of period:
Cash and cash equivalents	160,910	183,255
Restricted cash		198
Total cash, cash equivalents and restricted cash	$ 160,910	$ 183,453

Pay vs Performance Disclosure

Pay vs Performance Disclosure - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Pay vs Performance Disclosure
Net Income (Loss)	$ (63,169)	$ (35,467)

Insider Trading Arrangements

Insider Trading Arrangements	3 Months Ended
	Mar. 31, 2024 shares
Trading Arrangements, by Individual
Material Terms of Trading Arrangement	Other than as disclosed below, during the three months ended March 31, 2024, no director or “officer” (as defined in Rule 16a-1(f) under the Exchange Act) of the Company adopted or terminated a “Rule 10b5-1 trading arrangement” or “non-Rule 10b5-1 trading arrangement”, as each term is defined in Item 408(a) of Regulation S-K. On March 4, 2024 , Jean-Pierre Sommadossi , Ph.D., our President and Chief Executive Officer , adopted a Rule 10b5-1 trading arrangement, as defined in Item 408(a) of Regulation S-K, that is intended to satisfy the affirmative defense of Rule 10b5-1(c) for the sale of up to 1,200,000 shares of the Company’s common stock until June 4, 2025 .
Rule 10b5-1 Arrangement Adopted	true
Non-Rule 10b5-1 Arrangement Adopted	false
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false
Jean-Pierre Sommadossi
Trading Arrangements, by Individual
Name	Jean-Pierre Sommadossi
Title	President and Chief Executive Officer
Rule 10b5-1 Arrangement Adopted	true
Adoption Date	March 4, 2024
Aggregate Available	1,200,000
Expiration Date	June 4, 2025

Organization

Organization	3 Months Ended
	Mar. 31, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization	1. Organization Business Overview Atea Pharmaceuticals, Inc., together with its wholly owned subsidiary, Atea Pharmaceuticals Securities Corporation, is referred to herein on a consolidated basis as "Atea" or the "Company". The Company is a clinical-stage biopharmaceutical company focused on discovering, developing and commercializing antiviral therapeutics to improve the lives of patients suffering from serious viral infections. Currently, Atea is conducting SUNRISE-3, a Phase 3 clinical trial evaluating bemnifosbuvir for the treatment of Coronavirus disease 2019 ("COVID-19"). Atea is also currently conducting a Phase 2 clinical trial evaluating the combination of bemnifosbuvir and ruzasvir for the treatment of hepatitis C virus ("HCV"). Liquidity and Capital Resources As of March 31, 2024, the Company had $ 541.5 million in cash, cash equivalents and marketable securities, which the Company believes will be sufficient to fund its operations for a period through at least twelve months from the issuance date of these condensed consolidated financial statements. In November 2021, the Company entered into an open market sales agreement (“Sales Agreement”) with Jefferies LLC (“Jefferies”), under which the Company may from time to time offer and sell shares of its common stock for an aggregate offering price of up to $ 200.0 million, through or to Jefferies, acting as sales agent or principal. The shares will be offered and sold under the Company’s shelf registration statement on Form S-3 and a related prospectus filed with the Securities and Exchange Commission (“SEC”) on November 24, 2021, as amended. The Company has agreed to pay Jefferies a commission of 3.0 % of the aggregate gross proceeds from each sale of shares, reimburse legal fees and disbursements and provide Jefferies with customary indemnification and contribution rights. As of March 31, 2024, no shares have been issued under the Sales Agreement. Risks and Uncertainties The Company is subject to risks and uncertainties common to clinical-stage biopharmaceutical companies. These risks include, but are not limited to, potential failure of preclinical and clinical studies, uncertainties associated with research and development activities generally, competition from technical innovations of others, dependence upon key personnel, compliance with governmental regulations, the need to obtain marketing approval for any product candidate that the Company may develop, the need to gain broad acceptance among patients, payers and health care providers to successfully commercialize any product for which marketing approval is obtained and the need to secure and maintain adequate intellectual property protection for the Company’s proprietary technology and products. Further, the Company is currently dependent on third-party service providers for much of its preclinical research, clinical development and manufacturing activities. Product candidates currently under development, including most notably the combination of bemnifosbuvir and ruzasvir for the treatment of HCV, will require significant amounts of additional capital and additional research and development efforts, and all the Company’s product candidates will require regulatory approval, prior to commercialization. Even if the Company is able to generate revenues from the sale of its product candidates, if approved, it may not become profitable. If the Company fails to become profitable or is unable to sustain profitability on a continuing basis, then it may be unable to continue its operations at planned levels and be forced to reduce its operations. The Company may seek additional capital through one or more of a combination of financing through the sale of additional equity securities, debt financing, or funding in connection with any new collaborative relationships it may enter into or other arrangements. There can be no assurance that the Company will be able to obtain such additional funding, on terms acceptable to the Company, on a timely basis or at all. The terms of any financing may adversely affect the holdings or the rights of the Company’s existing stockholders. Geopolitical events, including civil or political unrest and terrorism, have resulted in a significant disruption of global business and financial markets. In addition, recent or future market volatility, increased inflation and higher interest rates, if sustained, may increase the Company’s cost of financing and may restrict our access to potential sources of future liquidity.

Summary of Significant Accounti

Summary of Significant Accounting Policies	3 Months Ended
	Mar. 31, 2024
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies Basis of Presentation The unaudited interim condensed consolidated financial statements of the Company included herein have been prepared in accordance with accounting principles generally accepted in the United States (“GAAP”) as found in the Accounting Standards Codification (“ASC”), Accounting Standards Update (“ASU”) of the Financial Accounting Standards Board (“FASB”) and the rules and regulations of the SEC. Certain information and footnote disclosures normally included in financial statements prepared in accordance with GAAP have been condensed or omitted from this report, as is permitted by such SEC rules and regulations. Accordingly, these unaudited condensed consolidated financial statements should be read in conjunction with the Company’s audited consolidated financial statements and the notes thereto for the year ended December 31, 2023 included in the Company’s Annual Report on Form 10-K filed with the SEC on February 28, 2024. Unaudited Interim Financial Information The accompanying condensed consolidated balance sheet as of March 31, 2024, the condensed consolidated statements of operations and comprehensive loss for the three months ended March 31, 2024 and 2023, the condensed consolidated statements of stockholders’ equity for the three months ended March 31, 2024 and 2023, and the condensed consolidated statements of cash flows for the three months ended March 31, 2024 and 2023 are unaudited. The unaudited interim financial statements have been prepared on the same basis as the audited annual financial statements and, in the opinion of management, reflect all adjustments, which include only normal recurring adjustments, necessary for the fair statement of the Company’s financial position as of March 31, 2024, the results of its operations for the three months ended March 31, 2024 and 2023 and its cash flows for the three months ended March 31, 2024 and 2023. The results for the three months ended March 31, 2024 are not necessarily indicative of results to be expected for the year ending December 31, 2024, or any other interim period. Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts reported in the condensed consolidated financial statements and in these accompanying notes. The Company bases its estimates on historical experience, known trends and other market-specific or other relevant factors and assumptions that it believes to be reasonable under the circumstances. On an ongoing basis, management evaluates its estimates, which include but are not limited to estimates of accrued research and development expenses, valuation of marketable securities, the valuation of stock-based awards, valuation of operating lease right-of-use assets and lease liabilities and income taxes. Changes in estimates are recorded in the period in which such changes become known. Principles of Consolidation The condensed consolidated financial statements include the accounts of Atea Pharmaceuticals, Inc. and its wholly-owned subsidiary, Atea Pharmaceuticals Securities Corporation. All intercompany amounts have been eliminated in consolidation. Significant Accounting Policies There were no changes in the Company’s significant accounting policies as described in the Annual Report on Form 10-K for the year ended December 31, 2023 filed with the SEC on February 28, 2024. Recently Issued Accounting Pronouncements From time to time, new accounting pronouncements are issued by the FASB or other 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 its condensed consolidated financial statements and disclosures.

Collaboration Agreement

Collaboration Agreement	3 Months Ended
	Mar. 31, 2024
Revenue from Contract with Customer [Abstract]
Collaboration Agreement	3. Collaboration Agreement In October 2020, the Company entered into a License Agreement (“Roche License Agreement”) with F. Hoffmann-LaRoche Ltd. and Genentech, Inc. (together, “Roche”) under which the Company granted an exclusive license for certain development and commercialization rights related to bemnifosbuvir outside of the United States (other than for certain HCV uses) to Roche. In November 2021, Roche provided the Company with a notice of termination of the Roche License Agreement which became effective in February 2022. Upon termination, the rights and licenses granted by the Company to Roche under the Roche License Agreement were returned to the Company, resulting in the Company having all rights to continue the clinical development and future commercialization of bemnifosbuvir worldwide. Global development plan activities and related cost sharing between the parties continued through the effective date of the termination. The activities to complete the global development plan were accounted for under ASC 808. Expenses incurred and reimbursements made or received from Roche were accounted for pursuant to ASC 730, Research and Development . As such, the Company was expensing costs as incurred, including any reimbursements made to Roche, and recognizing reimbursement received from Roche as a reduction of research and development expense through the effective date of the termination. For the three months ended March 31, 2024 and 2023, the Company recorded net credits of $ 1,292 and $ 1,000 , respectively, from Roche. The credits recorded represent changes in estimate as a result of close out activities and related reporting of amounts incurred by Roche associated with the global development plan. Included in prepaid expenses and other current assets as of March 31, 2024 is a net balance due from Roche of $ 1,292 .

Marketable Securities

Marketable Securities	3 Months Ended
	Mar. 31, 2024
Debt Securities, Available-for-Sale [Abstract]
Marketable Securities	4. Marketable Securities As of March 31, 2024 Amortized Cost Unrealized Gains Unrealized Losses Fair Value Marketable Securities US Treasury obligations $ 179,473 $ 14 $ ( 120 ) $ 179,367 US Government agency securities 95,570 22 ( 28 ) 95,564 Commercial paper 24,565 6 ( 19 ) 24,552 Corporate bonds 81,150 14 ( 66 ) 81,098 Total $ 380,758 $ 56 $ ( 233 ) $ 380,581 As of December 31, 2023 Amortized Cost Unrealized Gains Unrealized Losses Fair Value Marketable Securities US Treasury obligations $ 155,816 $ 145 $ ( 23 ) $ 155,938 US Government agency securities 178,115 96 ( 51 ) 178,160 Commercial paper 39,461 14 ( 27 ) 39,448 Corporate bonds 60,684 65 ( 12 ) 60,737 Total $ 434,076 $ 320 $ ( 113 ) $ 434,283 As of March 31, 2024, the Company held 54 securities that were in an unrealized loss position of $ 233 with an aggregate fair value of $ 261,065 . The Company has the intent and ability to hold such securities until recovery. As a result, the Company did no t record any charges for credit-related impairments for its marketable debt securities for the three months ended March 31, 2024. None of the securities had remaining maturities longer than one year as of March 31, 2024. The Company received proceeds of $ 223,998 and $ 181,106 from sales and maturities of marketable securities during the three months ended March 31, 2024 and 2023, respectively.

Fair Value Measurements

Fair Value Measurements	3 Months Ended
	Mar. 31, 2024
Fair Value Disclosures [Abstract]
Fair Value Measurements	5. Fair Value Measurements The following tables present information about the Company’s financial assets measured at fair value on a recurring basis and indicate the level of the fair value hierarchy utilized to determine such fair values: Fair Value Measurements as of Level 1 Level 2 Level 3 Total Cash equivalents Money market funds $ 151,176 $ — $ — $ 151,176 Commercial Paper — 7,432 — 7,432 Marketable Securities US Treasury obligations — 179,367 — 179,367 US Government agency securities — 95,564 — 95,564 Commercial paper — 24,552 — 24,552 Corporate bonds — 81,098 — 81,098 Total $ 151,176 $ 388,013 $ — $ 539,189 Fair Value Measurements as of Level 1 Level 2 Level 3 Total Cash equivalents Money market funds $ 143,740 $ — $ — $ 143,740 Marketable Securities US Treasury obligations — 155,938 — 155,938 US Government agency securities — 178,160 — 178,160 Commercial paper — 39,448 — 39,448 Corporate bonds — 60,737 — 60,737 Total $ 143,740 $ 434,283 $ — $ 578,023 The Company’s assets with fair value categorized as Level 1 within the fair value hierarchy include money market funds. Money market funds are publicly traded mutual funds and are presented as cash equivalents on the unaudited condensed consolidated balance sheets as of March 31, 2024 and December 31, 2023. The Company's assets with fair value categorized as Level 2 within the fair value hierarchy include commercial paper, governmental and corporate bonds and asset-backed securities with fair values determined by utilizing information from third party pricing sources for identical or similar assets and liabilities in active market. There were no transfers among Level 1, Level 2 or Level 3 categories in the three months ended March 31, 2024.

Accrued Expenses and Other Curr

Accrued Expenses and Other Current Liabilities	3 Months Ended
	Mar. 31, 2024
Payables and Accruals [Abstract]
Accrued Expenses and Other Current Liabilities	6. Accrued Expenses and Other Current Liabilities Accrued expenses and other current liabilities consist of the following: March 31, December 31, Research and development, including manufacturing and clinical expenditures $ 16,214 $ 20,999 Payroll and payroll related 2,333 5,696 Professional fees and other 858 669 Total accrued expenses and other current liabilities $ 19,405 $ 27,364

Common Stock

Common Stock	3 Months Ended
	Mar. 31, 2024
Equity [Abstract]
Common Stock	7. Common Stock At March 31, 2024, the authorized capital of the Company included 300,000,000 shares of Company's common stock, of which 84,223,100 shares of Company's common stock were issued and outstanding. On all matters to be voted upon by the holders of Company's common stock, holders of Company's common stock are entitled to one vote per share. The holders of Company's common stock have no preemptive, redemption or conversion rights.

Stock-based Compensation

Stock-based Compensation	3 Months Ended
	Mar. 31, 2024
Share-Based Payment Arrangement [Abstract]
Stock-based Compensation	8. Stock-based Compensation In October 2020, the Company’s shareholders approved the Company’s 2020 Incentive Award Plan (“2020 Plan”). The 2020 Plan initially provided for the issuance of up to 7,924,000 shares of Company's common stock and for the grant of incentive stock options or other incentive awards to employees, officers, directors and consultants of the Company. The number of shares of Company's common stock that may be issued under the 2020 Plan is also subject to increase on the first day of each calendar year equal to the lesser of i) 5 % of the aggregate number of shares of Company's common stock outstanding on the final day of the immediately preceding calendar year or ii) such smaller number of shares as is determined by the board of directors. Through December 31, 2023, the shares available under the plan were increased by 12,450,364 shares. In January 2024, the shares of the Company's common stock available under the 2020 Plan were increased by 4,171,775 shares. As of March 31, 2024, 5,743,729 shares of Company's common stock were available for future issuance under the 2020 Plan. The 2020 Plan replaced and is the successor of the Company’s 2013 Equity Incentive Plan, as amended (“2013 Plan”). Upon any cancellation of outstanding option awards to purchase shares of Company's common stock under the 2013 Plan, such shares will be made available for grant under the 2020 Plan. Restricted Stock Units During the three months ended March 31, 2024, the Company granted 948,500 restricted stock units to employees under the 2020 Plan with an aggregate grant date fair market value of $ 3,946 . The restricted stock unit awards vest in three annual installments. Below is the activity related to restricted stock units for the three months ended March 31, 2024. Number of Weighted Average Outstanding at January 1, 2024 2,337,517 $ 4.69 Granted 948,500 $ 4.16 Released ( 729,032 ) $ 4.80 Cancelled — $ — Unvested shares at March 31, 2024 2,556,985 $ 4.46 As of March 31, 2024, total unrecognized compensation expense related to restricted stock units was $ 9,977 , which amount is being recognized over a remaining weighted average period of 2.1 years. Performance-based Restricted Stock Units As of December 31, 2023 the Company had 724,970 performance-based restricted stock units (“2022 PSUs”) outstanding. The 2022 PSUs provide for a performance period from February 1, 2022 through January 31, 2025 to achieve up to six defined performance metrics. The percentage of 2022 PSUs eligible to vest will be determined based on the number of metrics achieved during the performance period and may range from 0 % to 200 %. The Company has not recognized any compensation expense through March 31, 2024, as achievement of the minimum performance criteria had not been deemed probable. The vesting of any eligible 2022 PSUs will occur in equal installments on January 31, 2025 and January 31, 2027. During the three months ended March 31, 2024, the Company granted 1,057,900 performance-based restricted stock units (“2024 PSUs”) to employees with an aggregate grant date fair value of $ 4,401 . The 2024 PSUs provide for a performance period from February 1, 2024 through January 31, 2027 to achieve up to four defined metrics. The percentage of 2024 PSUs eligible to vest will be determined based on the number of metrics achieved during the performance period and may range from 0 % to 200 %. As of March 31, 2024 one metric was deemed probable of achievement resulting in expense recognition of 50 % of the grant date value of the 2024 PSUs. Compensation expense is being recognized from the grant date through the final vest date of January 31, 2027. The Company recorded compensation expense of $ 120 for the three months ended March 31, 2024. The following table summarizes the activity related to performance-based restricted stock units for the three months ended March 31, 2024. Number of Weighted Average Outstanding at January 1, 2024 724,970 $ 7.14 Granted 1,057,900 $ 4.16 Released — $ — Cancelled — $ — Unvested shares at March 31, 2024 1,782,870 $ 5.37 Stock Options The following table summarizes stock option activity for the three months ended March 31, 2024. Number of Weighted Weighted Aggregate Outstanding at January 1, 2024 17,017,319 $ 15.30 7.1 $ 5,080 Granted 2,932,350 $ 4.16 Exercised — $ — Cancelled — $ — Outstanding at March 31, 2024 19,949,669 $ 13.67 7.3 $ 8,562 Vested and expected to vest at March 31, 2024 19,949,669 $ 13.67 7.3 $ 8,562 Vested and exercisable at March 31, 2024 12,080,821 $ 16.40 6.3 $ 8,370 During the three months ended March 31, 2024 the Company granted 2,932,350 stock options with an aggregate grant date fair value of $ 9,043 . The aggregate intrinsic value of stock options is calculated as the difference between the exercise price of the stock options and the estimated fair value of the Company’s common stock for those stock options that had exercise prices lower than the fair value of the Company’s common stock. Stock options generally vest over a service period of four years after grant and have a contractual term of ten years . As of March 31, 2024, total unrecognized compensation expense related to stock option awards was $ 53,058 , which amount is being recognized over a remaining weighted average period of 2.6 years. Employee Stock Purchase Plan In October 2020, the Company’s shareholders approved the Employee Stock Purchase Plan (“ESPP”), which became effective upon the closing of the Company’s initial public offering ("IPO") in November 2020. The Company initially reserved a total of 1,187,000 shares of Company's common stock for issuance under the ESPP. The ESPP provides that the number of shares reserved and available for issuance under the ESPP will be increased on January 1 of each calendar year by 1 % of the number of shares of Company's common stock issued and outstanding on the immediately preceding December 31 or such lesser amount as specified by the board of directors. Through December 31, 2022, there was no increase in the number of shares reserved for issuance under the ESPP. In January 2023 and January 2024, the number of shares of the Company's common stock available for issuance under the ESPP was increased by 832,876 shares and 834,355 shares, respectively. As of March 31, 2024, 2,672,701 shares of Company's common stock were available for issuance under the ESPP. Under the ESPP, the Company issued 58,555 shares of Company's common stock for proceeds of $ 150 during the three months ended March 31, 2024. Stock-based Compensation Expense Stock-based compensation expense by award type included within the unaudited condensed consolidated statements of operations and comprehensive loss was as follows: Three Months Ended 2024 2023 Stock options $ 11,141 $ 11,880 Restricted stock units 1,290 600 Performance-based stock units 120 — Employee stock purchase plan 35 55 Total stock-based compensation expense $ 12,586 $ 12,535 Stock-based compensation expense is classified as follows: Three Months Ended 2024 2023 Research and development expense $ 5,981 $ 5,928 General and administrative 6,605 6,607 Total stock-based compensation expense $ 12,586 $ 12,535

Net Loss Per Share

Net Loss Per Share	3 Months Ended
	Mar. 31, 2024
Earnings Per Share [Abstract]
Net Loss Per Share	9. Net Loss Per Share Basic and diluted earnings per share are calculated as follows: Three Months Ended 2024 2023 Net loss $ ( 63,169 ) $ ( 35,467 ) Weighted average common shares outstanding, basic and diluted 83,916,193 83,332,397 Net loss per share, basic and diluted $ ( 0.75 ) $ ( 0.43 ) The following shares were excluded from the computation of the net loss per share for the three months ended March 31, 2024 and 2023, respectively, due to the net loss during the periods as their effect is antidilutive. As of March 31, 2024 2023 Stock options 19,949,669 16,652,174 Restricted stock units 2,556,985 2,145,617 Performance-based restricted stock units 1,782,870 724,970

Leases

Leases	3 Months Ended
	Mar. 31, 2024
Leases [Abstract]
Leases	10. Leases The Company has a non-cancelable operating lease agreement for its office space in Boston, Massachusetts at 225 Franklin Street ("225 Lease"). The 225 Lease commencement date was January 1, 2022 and the 225 Lease runs through December 31, 2026 . The 225 Lease does no t contain any options for renewal or extension. In connection with the 225 Lease commencement, the Company recorded a right-of-use asset and operating lease liability of $ 2,938 and $ 2,873 as of January 1, 2022. The following assets and liabilities are recorded on the Company’s consolidated balance sheet as of March 31, 2024. As of March 31, 2024 Right-of-use asset $ 1,684 Current lease liability 769 Non-current lease liability 1,445 Future minimum payments under the 225 Lease, currently the Company’s only operating lease as of March 31, 2024 were as follows. As of March 31, 2024 Remainder of 2024 $ 616 2025 838 2026 855 Total lease payments 2,309 Less amount representing implied interest 95 Total lease liability $ 2,214 Current portion of operating lease liabilities $ 769 Non-current portion of operating lease liabilities $ 1,445 For the three months ended March 31, 2024 and 2023, respectively, the Company recorded operating lease costs of $ 161 , relating to its operating lease agreements.

Income Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2024
Income Tax Disclosure [Abstract]
Income Taxes	11. Income Taxes The Company recorded income tax expense of $ 231 and $ 197 for the three months ended March 31, 2024 and 2023, respectively. The Company maintained a full valuation allowance for the three months ended March 31, 2024 and 2023 due to uncertainty regarding its ability to utilize deferred tax assets.

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2024
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	12. Commitments and Contingencies License Agreement In December 2021, the Company entered into a license agreement (“Merck License Agreement”) with MSD International GmbH, an affiliate of Merck & Co, Inc. (“Merck”) for the development, manufacture and commercialization of ruzasvir. Ruzasvir is the NS5A inhibitor the Company is developing in combination with bemnifosbuvir for the treatment of HCV. Pursuant to the terms of the Merck License Agreement, the Company obtained from Merck a worldwide exclusive (subject to certain reserved rights to conduct internal research) and, sublicensable license under certain Merck patents and know-how to research, develop, manufacture, have manufactured, use, import, export, sell, offer for sale, and otherwise commercialize ruzasvir or products containing ruzasvir (each a “Product”) for all therapeutic or prophylactic uses in humans. In addition to a non-refundable upfront payment that the Company made in February 2022, the Company will be required to pay Merck milestone payments upon its achievement of certain development, regulatory and sales-based milestones. Additionally, the Company will pay Merck tiered royalties based on annual net sales of Products ranging from high single digits to mid-teens percentages. The Company’s royalty payment obligations will continue until the later of (i) the expiration of the last to expire valid claim of a licensed Merck patent claiming such Product and (ii) a period of years after the first commercial sale of such Product in such country. The Company may terminate the Merck License Agreement for convenience upon prior written notice. The first potential milestone in the amount of $ 5.0 million would be payable upon the commencement of a Phase 3 clinical trial. Contingent Consulting Fee The Company has an agreement with a consultant that requires payment of a success fee calculated as a percentage of certain product sales, subject to a cumulative maximum payout of $ 5.0 million. This success payment is contingent upon the occurrence of future events and the timing and likelihood of such payment is neither probable nor estimable. Indemnification The Company enters into certain types of contracts that contingently require the Company to indemnify various parties against claims from third parties. These contracts primarily relate to (i) the Company’s bylaws, under which the Company must indemnify directors and executive officers, and may indemnify other officers and employees, for liabilities arising out of their relationship with the Company, (ii) contracts under which the Company must indemnify directors and certain officers and consultants for liabilities arising out of their relationship with the Company, and (iii) procurement, service or license agreements under which the Company may be required to indemnify vendors, service providers or licensees for certain claims, including claims that may be brought against such third parties arising from the Company’s acts or omissions with respect to the Company’s products, technology, intellectual property or services. From time to time, the Company may receive indemnification claims under these contracts in the normal course of business. In the event that one or more of these matters were to result in a claim against the Company, an adverse outcome, including a judgment or settlement, may cause a material adverse effect on the Company’s future business, operating results or financial condition. It is not possible to determine the maximum potential amount payable under these contracts since the Company has no history of prior indemnification claims and the unique facts and circumstances involved in each particular claim will be determinative.

Benefit Plan

Benefit Plan	3 Months Ended
	Mar. 31, 2024
Retirement Benefits [Abstract]
Benefit Plan	13. Benefit Plan The Company's defined contribution plan under Section 401(k) of the Internal Revenue Code (“401(k) Plan”) covers substantially all employees who meet minimum age and service requirements. Under the terms of the 401(k) Plan, the Company records matching contributions up to 4 % of the participant’s eligible compensation. During the three months ended March 31, 2024 and 2023, the Company recognized expense of $ 401 and $ 394 , respectively, relating to matching contributions to the 401(k) Plan.

Related Party Transactions

Related Party Transactions	3 Months Ended
	Mar. 31, 2024
Related Party Transactions [Abstract]
Related Party Transactions	14. Related Party Transactions The Company is party to a consulting agreement with an entity controlled by one of its directors. The agreement provides for an annual retainer of $ 110 . The Company recognized expense in the amount of $ 27 for each of the three month periods ended March 31, 2024 and 2023, respectively. In June 2022, the Company entered into a consulting agreement with one of its directors. No expense was recognized in connection with this agreement for the three months ended March 31, 2024 or 2023.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2024
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The unaudited interim condensed consolidated financial statements of the Company included herein have been prepared in accordance with accounting principles generally accepted in the United States (“GAAP”) as found in the Accounting Standards Codification (“ASC”), Accounting Standards Update (“ASU”) of the Financial Accounting Standards Board (“FASB”) and the rules and regulations of the SEC. Certain information and footnote disclosures normally included in financial statements prepared in accordance with GAAP have been condensed or omitted from this report, as is permitted by such SEC rules and regulations. Accordingly, these unaudited condensed consolidated financial statements should be read in conjunction with the Company’s audited consolidated financial statements and the notes thereto for the year ended December 31, 2023 included in the Company’s Annual Report on Form 10-K filed with the SEC on February 28, 2024.
Unaudited Interim Financial Information	Unaudited Interim Financial Information The accompanying condensed consolidated balance sheet as of March 31, 2024, the condensed consolidated statements of operations and comprehensive loss for the three months ended March 31, 2024 and 2023, the condensed consolidated statements of stockholders’ equity for the three months ended March 31, 2024 and 2023, and the condensed consolidated statements of cash flows for the three months ended March 31, 2024 and 2023 are unaudited. The unaudited interim financial statements have been prepared on the same basis as the audited annual financial statements and, in the opinion of management, reflect all adjustments, which include only normal recurring adjustments, necessary for the fair statement of the Company’s financial position as of March 31, 2024, the results of its operations for the three months ended March 31, 2024 and 2023 and its cash flows for the three months ended March 31, 2024 and 2023. The results for the three months ended March 31, 2024 are not necessarily indicative of results to be expected for the year ending December 31, 2024, or any other interim period.
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 amounts reported in the condensed consolidated financial statements and in these accompanying notes. The Company bases its estimates on historical experience, known trends and other market-specific or other relevant factors and assumptions that it believes to be reasonable under the circumstances. On an ongoing basis, management evaluates its estimates, which include but are not limited to estimates of accrued research and development expenses, valuation of marketable securities, the valuation of stock-based awards, valuation of operating lease right-of-use assets and lease liabilities and income taxes. Changes in estimates are recorded in the period in which such changes become known.
Principles of Consolidation	Principles of Consolidation The condensed consolidated financial statements include the accounts of Atea Pharmaceuticals, Inc. and its wholly-owned subsidiary, Atea Pharmaceuticals Securities Corporation. All intercompany amounts have been eliminated in consolidation.
Significant Accounting Policies	Significant Accounting Policies There were no changes in the Company’s significant accounting policies as described in the Annual Report on Form 10-K for the year ended December 31, 2023 filed with the SEC on February 28, 2024.
Recently Issued Accounting Pronouncements	Recently Issued Accounting Pronouncements From time to time, new accounting pronouncements are issued by the FASB or other 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 its condensed consolidated financial statements and disclosures.

Marketable Securities (Tables)

Marketable Securities (Tables)	3 Months Ended
	Mar. 31, 2024
Debt Securities, Available-for-Sale [Abstract]
Schedule of Marketable Securities	As of March 31, 2024 Amortized Cost Unrealized Gains Unrealized Losses Fair Value Marketable Securities US Treasury obligations $ 179,473 $ 14 $ ( 120 ) $ 179,367 US Government agency securities 95,570 22 ( 28 ) 95,564 Commercial paper 24,565 6 ( 19 ) 24,552 Corporate bonds 81,150 14 ( 66 ) 81,098 Total $ 380,758 $ 56 $ ( 233 ) $ 380,581 As of December 31, 2023 Amortized Cost Unrealized Gains Unrealized Losses Fair Value Marketable Securities US Treasury obligations $ 155,816 $ 145 $ ( 23 ) $ 155,938 US Government agency securities 178,115 96 ( 51 ) 178,160 Commercial paper 39,461 14 ( 27 ) 39,448 Corporate bonds 60,684 65 ( 12 ) 60,737 Total $ 434,076 $ 320 $ ( 113 ) $ 434,283

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 2024
Fair Value Disclosures [Abstract]
Schedule of Financial Assets Measured at Fair Value on Recurring Basis	The following tables present information about the Company’s financial assets measured at fair value on a recurring basis and indicate the level of the fair value hierarchy utilized to determine such fair values: Fair Value Measurements as of Level 1 Level 2 Level 3 Total Cash equivalents Money market funds $ 151,176 $ — $ — $ 151,176 Commercial Paper — 7,432 — 7,432 Marketable Securities US Treasury obligations — 179,367 — 179,367 US Government agency securities — 95,564 — 95,564 Commercial paper — 24,552 — 24,552 Corporate bonds — 81,098 — 81,098 Total $ 151,176 $ 388,013 $ — $ 539,189 Fair Value Measurements as of Level 1 Level 2 Level 3 Total Cash equivalents Money market funds $ 143,740 $ — $ — $ 143,740 Marketable Securities US Treasury obligations — 155,938 — 155,938 US Government agency securities — 178,160 — 178,160 Commercial paper — 39,448 — 39,448 Corporate bonds — 60,737 — 60,737 Total $ 143,740 $ 434,283 $ — $ 578,023

Accrued Expenses and Other Cu_2

Accrued Expenses and Other Current Liabilities (Tables)	3 Months Ended
	Mar. 31, 2024
Payables and Accruals [Abstract]
Schedule of Accrued Expenses and Other Current Liabilities	Accrued expenses and other current liabilities consist of the following: March 31, December 31, Research and development, including manufacturing and clinical expenditures $ 16,214 $ 20,999 Payroll and payroll related 2,333 5,696 Professional fees and other 858 669 Total accrued expenses and other current liabilities $ 19,405 $ 27,364

Stock-based Compensation (Table

Stock-based Compensation (Tables)	3 Months Ended
	Mar. 31, 2024
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Summary of Stock Options Activity	The following table summarizes stock option activity for the three months ended March 31, 2024. Number of Weighted Weighted Aggregate Outstanding at January 1, 2024 17,017,319 $ 15.30 7.1 $ 5,080 Granted 2,932,350 $ 4.16 Exercised — $ — Cancelled — $ — Outstanding at March 31, 2024 19,949,669 $ 13.67 7.3 $ 8,562 Vested and expected to vest at March 31, 2024 19,949,669 $ 13.67 7.3 $ 8,562 Vested and exercisable at March 31, 2024 12,080,821 $ 16.40 6.3 $ 8,370
Summary of Stock-based Compensation Expense by Award Type	Stock-based compensation expense by award type included within the unaudited condensed consolidated statements of operations and comprehensive loss was as follows: Three Months Ended 2024 2023 Stock options $ 11,141 $ 11,880 Restricted stock units 1,290 600 Performance-based stock units 120 — Employee stock purchase plan 35 55 Total stock-based compensation expense $ 12,586 $ 12,535
Schedule of Stock-based Compensation Expense	Stock-based compensation expense is classified as follows: Three Months Ended 2024 2023 Research and development expense $ 5,981 $ 5,928 General and administrative 6,605 6,607 Total stock-based compensation expense $ 12,586 $ 12,535
Restricted Stock Units
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Summary of Restricted Stock Units	Below is the activity related to restricted stock units for the three months ended March 31, 2024. Number of Weighted Average Outstanding at January 1, 2024 2,337,517 $ 4.69 Granted 948,500 $ 4.16 Released ( 729,032 ) $ 4.80 Cancelled — $ — Unvested shares at March 31, 2024 2,556,985 $ 4.46
Performance-based Restricted Stock Units
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Summary of Restricted Stock Units	The following table summarizes the activity related to performance-based restricted stock units for the three months ended March 31, 2024. Number of Weighted Average Outstanding at January 1, 2024 724,970 $ 7.14 Granted 1,057,900 $ 4.16 Released — $ — Cancelled — $ — Unvested shares at March 31, 2024 1,782,870 $ 5.37

Net Loss Per Share (Tables)

Net Loss Per Share (Tables)	3 Months Ended
	Mar. 31, 2024
Earnings Per Share [Abstract]
Summary of Basic and Diluted Earnings Per Share	Basic and diluted earnings per share are calculated as follows: Three Months Ended 2024 2023 Net loss $ ( 63,169 ) $ ( 35,467 ) Weighted average common shares outstanding, basic and diluted 83,916,193 83,332,397 Net loss per share, basic and diluted $ ( 0.75 ) $ ( 0.43 )
Summary of Antidilutive Securities Excluded from Computation of Net Loss Per Share	The following shares were excluded from the computation of the net loss per share for the three months ended March 31, 2024 and 2023, respectively, due to the net loss during the periods as their effect is antidilutive. As of March 31, 2024 2023 Stock options 19,949,669 16,652,174 Restricted stock units 2,556,985 2,145,617 Performance-based restricted stock units 1,782,870 724,970

Leases (Tables)

Leases (Tables)	3 Months Ended
	Mar. 31, 2024
Leases [Abstract]
Summary of Assets and Liabilities Recorded on Balance Sheet	The following assets and liabilities are recorded on the Company’s consolidated balance sheet as of March 31, 2024. As of March 31, 2024 Right-of-use asset $ 1,684 Current lease liability 769 Non-current lease liability 1,445
Summary of Future Minimum Payments under Operating Leases	Future minimum payments under the 225 Lease, currently the Company’s only operating lease as of March 31, 2024 were as follows. As of March 31, 2024 Remainder of 2024 $ 616 2025 838 2026 855 Total lease payments 2,309 Less amount representing implied interest 95 Total lease liability $ 2,214 Current portion of operating lease liabilities $ 769 Non-current portion of operating lease liabilities $ 1,445

Organization - Additional Infor

Organization - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Dec. 31, 2023	Nov. 30, 2021
Organization [Line Items]
Cash and cash equivalents and marketable securities	$ 541.5
Number of shares issued	84,223,100	83,435,513
Sales Agreement | Jeffries
Organization [Line Items]
Commission percentage of aggregate gross proceeds from each sale of shares	3%
Number of shares issued	0
Sales Agreement | Jeffries | Maximum
Organization [Line Items]
Aggregate offering price			$ 200

Collaboration Agreement - Addit

Collaboration Agreement - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Disaggregation Of Revenue [Line Items]
Prepaid expenses and other current assets	$ 7,273		$ 12,349
Roche License Agreement
Disaggregation Of Revenue [Line Items]
Research and development net credits adjustment	1,292	$ 1,000
Prepaid expenses and other current assets	$ 1,292

Marketable Securities - Additio

Marketable Securities - Additional Information (Details)	3 Months Ended
	Mar. 31, 2024 USD ($) Security	Mar. 31, 2023 USD ($)
Debt Securities, Available-for-Sale [Abstract]
Number of held securities | Security	54
Debt securities in unrealized loss position	$ 233,000
Aggregate fair value	261,065,000
Marketable debt securities, charges for credit-related impairments	0
Securities maturing longer than one year	0
Proceeds from sales and maturities of marketable securities	$ 223,998,000	$ 181,106,000

Marketable Securities - Schedul

Marketable Securities - Schedule of Marketable Securities (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost	$ 380,758	$ 434,076
Unrealized Gains	56	320
Unrealized Losses	(233)	(113)
Fair Value	380,581	434,283
U.S. Treasury obligations
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost	179,473	155,816
Unrealized Gains	14	145
Unrealized Losses	(120)	(23)
Fair Value	179,367	155,938
U.S. Government agency securities
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost	95,570	178,115
Unrealized Gains	22	96
Unrealized Losses	(28)	(51)
Fair Value	95,564	178,160
Commercial paper
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost	24,565	39,461
Unrealized Gains	6	14
Unrealized Losses	(19)	(27)
Fair Value	24,552	39,448
Corporate bonds
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost	81,150	60,684
Unrealized Gains	14	65
Unrealized Losses	(66)	(12)
Fair Value	$ 81,098	$ 60,737

Fair Value Measurements - Sched

Fair Value Measurements - Schedule of Financial Assets Measured at Fair Value on Recurring Basis (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Cash equivalents
Marketable securities	$ 380,581	$ 434,283
Total	539,189	578,023
Level 1
Cash equivalents
Total	151,176	143,740
Level 2
Cash equivalents
Total	388,013	434,283
U.S. Treasury obligations
Cash equivalents
Marketable securities	179,367	155,938
U.S. Treasury obligations | Level 2
Cash equivalents
Marketable securities	179,367	155,938
U.S. Government agency securities
Cash equivalents
Marketable securities	95,564	178,160
U.S. Government agency securities | Level 2
Cash equivalents
Marketable securities	95,564	178,160
Commercial paper
Cash equivalents
Cash equivalents	7,432
Marketable securities	24,552	39,448
Commercial paper | Level 2
Cash equivalents
Cash equivalents	7,432
Marketable securities	24,552	39,448
Corporate bonds
Cash equivalents
Marketable securities	81,098	60,737
Corporate bonds | Level 2
Cash equivalents
Marketable securities	81,098	60,737
Money Market Funds
Cash equivalents
Cash equivalents	151,176	143,740
Money Market Funds | Level 1
Cash equivalents
Cash equivalents	$ 151,176	$ 143,740

Accrued Expenses and Other Cu_3

Accrued Expenses and Other Current Liabilities - Schedule of Accrued Expenses and Other Current Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Payables and Accruals [Abstract]
Research and development, including manufacturing and clinical expenditures	$ 16,214	$ 20,999
Payroll and payroll related	2,333	5,696
Professional fees and other	858	669
Total accrued expenses and other current liabilities	$ 19,405	$ 27,364

Common Stock - Additional Infor

Common Stock - Additional Information (Details) - shares	3 Months Ended
	Mar. 31, 2024	Dec. 31, 2023
Equity [Abstract]
Common stock, shares authorized	300,000,000	300,000,000
Common stock, shares issued	84,223,100	83,435,513
Common stock, shares outstanding	84,223,100	83,435,513
Common stock voting rights per share	On all matters to be voted upon by the holders of Company's common stock, holders of Company's common stock are entitled to one vote per share.

Stock-based Compensation - Addi

Stock-based Compensation - Additional Information (Details) $ in Thousands	1 Months Ended			3 Months Ended		39 Months Ended
	Jan. 31, 2024 shares	Jan. 31, 2023 shares	Oct. 31, 2020 shares	Mar. 31, 2024 USD ($) Installment shares	Mar. 31, 2023 USD ($) shares	Dec. 31, 2023 shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares granted				2,932,350
Compensation expense | $				$ 12,586	$ 12,535
Gross proceeds from issuance of common stock | $				$ 150	$ 165
Common Stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Issuance of common stock under ESPP, shares				58,555	57,803
Restricted Stock Units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of units granted				948,500
Number of units cancelled due to terminations				0
Aggregate grant date fair market value of restricted stock units granted | $				$ 3,946
Number of installments | Installment				3
Unrecognized compensation expense | $				$ 9,977
Remaining weighted average period for recognize compensation expense				2 years 1 month 6 days
Stock units outstanding				2,556,985		2,337,517
Compensation expense | $				$ 1,290	$ 600
Performance-based Restricted Stock Units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of units granted				1,057,900
Stock units outstanding				1,782,870		724,970
Compensation expense | $				$ 120
2022 Performance-based Restricted Stock Units [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Performance based restricted stock units terms of award				The 2022 PSUs provide for a performance period from February 1, 2022 through January 31, 2025 to achieve up to six defined performance metrics. The percentage of 2022 PSUs eligible to vest will be determined based on the number of metrics achieved during the performance period and may range from 0% to 200%. The Company has not recognized any compensation expense through March 31, 2024, as achievement of the minimum performance criteria had not been deemed probable. The vesting of any eligible 2022 PSUs will occur in equal installments on January 31, 2025 and January 31, 2027.
Stock units outstanding						724,970
2024 Performance-based Restricted Stock Units [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of units granted				1,057,900
Aggregate grant date fair market value of restricted stock units granted | $				$ 4,401
Triggering expense recognition				50%
Performance based restricted stock units terms of award				The 2024 PSUs provide for a performance period from February 1, 2024 through January 31, 2027 to achieve up to four defined metrics. The percentage of 2024 PSUs eligible to vest will be determined based on the number of metrics achieved during the performance period and may range from 0% to 200%. As of March 31, 2024 one metric was deemed probable of achievement resulting in expense recognition of 50% of the grant date value of the 2024 PSUs. Compensation expense is being recognized from the grant date through the final vest date of January 31, 2027.
Employee Stock Option
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares granted				2,932,350
Aggregate grant date fair market value | $				$ 9,043
Vesting service period				4 years
Award contractual term				10 years
Unrecognized compensation expense | $				$ 53,058
Remaining weighted average period for recognize compensation expense				2 years 7 months 6 days
Compensation expense | $				$ 11,141	11,880
Employee Stock Purchase Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Percentage of shares of common stock Outstanding			1%
Common stock available for issuance				2,672,701
Compensation expense | $				$ 35	$ 55
Common stock, capital shares reserved for future issuance			1,187,000
Issuance of common stock under ESPP, shares				58,555
Gross proceeds from issuance of common stock | $				$ 150
Employee Stock Purchase Plan | Common Stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Increased number of shares available under plan	834,355	832,876
2020 Incentive Award Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Increased number of shares available under plan	4,171,775					12,450,364
Percentage of shares of common stock Outstanding			5%
Common stock available for issuance				5,743,729
Minimum | 2022 Performance-based Restricted Stock Units [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Award vesting percentage				0%
Minimum | 2024 Performance-based Restricted Stock Units [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Award vesting percentage				0%
Maximum | 2022 Performance-based Restricted Stock Units [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Award vesting percentage				200%
Maximum | 2024 Performance-based Restricted Stock Units [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Award vesting percentage				200%
Maximum | 2020 Incentive Award Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares available for grant			7,924,000

Stock-based Compensation - Summ

Stock-based Compensation - Summary of Restricted Stock Units (Details)	3 Months Ended
	Mar. 31, 2024 $ / shares shares
Restricted Stock Units
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Number of shares, Outstanding | shares	2,337,517
Number of shares, Granted | shares	948,500
Number of shares, Released | shares	(729,032)
Number of shares, Cancelled | shares	0
Number of shares, Unvested | shares	2,556,985
Weighted Average Grant Date Fair Value, Outstanding | $ / shares	$ 4.69
Weighted Average Grant Date Fair Value, Granted | $ / shares	4.16
Weighted Average Grant Date Fair Value, Released | $ / shares	4.8
Weighted Average Grant Date Fair Value, Cancelled | $ / shares	0
Weighted Average Grant Date Fair Value, Unvested | $ / shares	$ 4.46
Performance-based Restricted Stock Units
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Number of shares, Outstanding | shares	724,970
Number of shares, Granted | shares	1,057,900
Number of shares, Unvested | shares	1,782,870
Weighted Average Grant Date Fair Value, Outstanding | $ / shares	$ 7.14
Weighted Average Grant Date Fair Value, Granted | $ / shares	4.16
Weighted Average Grant Date Fair Value, Unvested | $ / shares	$ 5.37

Stock-based Compensation - Su_2

Stock-based Compensation - Summary of Stock Options Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2024	Dec. 31, 2023
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding [Roll Forward]
Number of Shares, Outstanding	17,017,319
Number of Shares, Granted	2,932,350
Number of Shares, Outstanding	19,949,669	17,017,319
Number of Shares, Vested and expected to vest	19,949,669
Number of Shares, Vested and exercisable	12,080,821
Weighted Average Exercise Price Per Share
Weighted Average Exercise Price Per Share, Outstanding	$ 15.3
Weighted Average Exercise Price Per Share, Granted	4.16
Weighted Average Exercise Price Per Share, Outstanding	13.67	$ 15.3
Weighted Average Exercise Price Per Share, Vested and expected to vest	13.67
Weighted Average Exercise Price Per Share, Vested and exercisable	$ 16.4
Weighted Average Remaining Contractual Term and Aggregate Intrinsic Value
Weighted Average Remaining Contractual Term (years), Outstanding	7 years 3 months 18 days	7 years 1 month 6 days
Weighted Average Remaining Contractual Term (years), Vested and expected to vest	7 years 3 months 18 days
Weighted Average Remaining Contractual Term (years), Vested and exercisable	6 years 3 months 18 days
Aggregate Intrinsic Value, Outstanding	$ 8,562	$ 5,080
Aggregate Intrinsic Value, Vested and expected to vest	8,562
Aggregate Intrinsic Value, Vested and exercisable	$ 8,370

Stock-based Compensation - Su_3

Stock-based Compensation - Summary of Stock-based Compensation Expense by Award Type (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total stock-based compensation expense	$ 12,586	$ 12,535
Employee Stock Option
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total stock-based compensation expense	11,141	11,880
Restricted Stock Units
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total stock-based compensation expense	1,290	600
Performance-based Stock Units
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total stock-based compensation expense	120
Employee Stock Purchase Plan
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total stock-based compensation expense	$ 35	$ 55

Stock-based Compensation - Stoc

Stock-based Compensation - Stock-based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation expense	$ 12,586	$ 12,535
Research and Development Expense
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation expense	5,981	5,928
General and Administrative
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation expense	$ 6,605	$ 6,607

Net Loss Per Share - Summary of

Net Loss Per Share - Summary of Basic and Diluted Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Earnings Per Share [Abstract]
Net loss	$ (63,169)	$ (35,467)
Weighted average common shares outstanding, basic	83,916,193	83,332,397
Weighted average common shares outstanding, diluted	83,916,193	83,332,397
Net loss per share, basic	$ (0.75)	$ (0.43)
Net loss per share, diluted	$ (0.75)	$ (0.43)

Net Loss Per Share - Summary _2

Net Loss Per Share - Summary of Antidilutive Securities Excluded from Computation of Net Loss Per Share (Details) - shares	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Employee Stock Option
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Number of shares excluded from computation of diluted net income per share	19,949,669	16,652,174
Restricted Stock Units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Number of shares excluded from computation of diluted net income per share	2,556,985	2,145,617
Performance-based Restricted Stock Units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Number of shares excluded from computation of diluted net income per share	1,782,870	724,970

Leases - Additional Information

Leases - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023	Jan. 01, 2022
Lessor, Lease, Description [Line Items]
Operating lease right-of-use assets, net	$ 1,684		$ 1,828
Operating lease liability	2,214
Operating lease costs	$ 161	$ 161
Office Space
Lessor, Lease, Description [Line Items]
Location of office space	Boston, Massachusetts at 225 Franklin Street
Lease commencement date	Jan. 01, 2022
Lease expiration date	Dec. 31, 2026
Lessor, Operating Lease, Existence of Option to Extend [true false]	false
Operating lease right-of-use assets, net				$ 2,938
Operating lease liability				$ 2,873

Leases - Summary of Assets and

Leases - Summary of Assets and Liabilities Recorded on Consolidated Balance Sheet (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Leases [Abstract]
Right-of-use asset	$ 1,684	$ 1,828
Current lease liability	769	760
Non-current lease liability	$ 1,445	$ 1,642

Leases - Future Minimum Payment

Leases - Future Minimum Payments under Operating Leases (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Leases [Abstract]
Remainder of 2024	$ 616
2025	838
2026	855
Total lease payments	2,309
Less amount representing implied interest	95
Total lease liability	2,214
Current portion of operating lease liabilities	769	$ 760
Non-current portion of operating lease liabilities	$ 1,445	$ 1,642

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Income Tax Disclosure [Abstract]
Income tax expense (benefit)	$ 231	$ 197

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Details)	3 Months Ended
	Mar. 31, 2024 USD ($)
Business Development Consulting Agreements | Maximum
Loss Contingencies [Line Items]
Success fee	$ 5,000,000
Merck License Agreement
Loss Contingencies [Line Items]
Milestone payments	$ 5,000,000

Benefit Plan - Additional Infor

Benefit Plan - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Defined Benefit Plan Disclosure [Line Items]
Defined contribution plan recognized expense related to matching contributions	$ 401	$ 394
Maximum
Defined Benefit Plan Disclosure [Line Items]
Defined contribution plan, employer matching contribution, percentage	4%

Related Party Transactions - Ad

Related Party Transactions - Additional Information (Details) - Consulting Agreement - USD ($)	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Entity Controlled by Director
Related Party Transaction [Line Items]
Annual retainer	$ 110,000
Related Party | Director
Related Party Transaction [Line Items]
Related party transaction expense	0	$ 0
Related Party | Entity Controlled by Director
Related Party Transaction [Line Items]
Related party transaction expense	$ 27,000	$ 27,000