0001564590-20-056724 | 10-Q | XBRL Viewer

Document and Entity Information - shares	9 Months Ended
Document and Entity Information - shares	Sep. 30, 2020	Dec. 10, 2020
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2020
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q3
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	false
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
Entity Common Stock, Shares Outstanding		82,616,937
Entity Current Reporting Status	No
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	125 Summer Street
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

Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Current assets
Cash and cash equivalents	$ 105,383	$ 21,661
Prepaid expenses and other current assets	3,030	249
Total current assets	108,413	21,910
Property and equipment, net	49	41
Other assets	1,644	122
Total assets	110,106	22,073
Current liabilities
Accounts payable	4,476	548
Accrued expenses and other current liabilities	6,340	1,887
Total current liabilities	10,816	2,435
Other liabilities	56	95
Total liabilities	10,872	2,530
Commitments and contingencies (see Note 6)
Convertible preferred stock, $0.001 par value; 57,932,090 and 33,645,447 shares authorized as of September 30, 2020 and December 31, 2019, respectively; 48,958,829 and 33,645,447 shares issued and outstanding as of September 30, 2020 and December 31, 2019, respectively; liquidation preference of $178,106 and $70,606 as of September 30, 2020 and December 31, 2019, respectively	175,745	69,114
Stockholders’ equity (deficit):
Common stock, $0.001 par value; 80,529,575 and 53,070,161 shares authorized as of September 30, 2020 and December 31, 2019, respectively; 10,109,847 and 10,091,100 shares issued and outstanding as of September 30, 2020 and December 31, 2019, respectively	10	10
Additional paid-in capital	9,295	4,632
Accumulated deficit	(85,816)	(54,213)
Total stockholders’ deficit	(76,511)	(49,571)
Total liabilities, convertible preferred stock and stockholders’ deficit	$ 110,106	$ 22,073

Consolidated Balance Sheets (Parenthetical) (Unaudited) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Statement Of Financial Position [Abstract]
Convertible preferred stock, par value	$ 0.001	$ 0.001
Convertible preferred stock, shares authorized	57,932,090	33,645,447
Convertible preferred stock, shares issued	48,958,829	33,645,447
Convertible preferred stock, shares outstanding	48,958,829	33,645,447
Convertible preferred stock, liquidation preference	$ 178,106	$ 70,606
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized	80,529,575	53,070,161
Common stock, shares issued	10,109,847	10,091,100
Common stock, shares outstanding	10,109,847	10,091,100

Consolidated Statements of Operations and Comprehensive Loss (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Operating expenses
Research and development	$ 13,601	$ 2,411	$ 24,177	$ 6,681
General and administrative	4,028	1,358	7,500	3,178
Total operating expenses	17,629	3,769	31,677	9,859
Loss from operations	(17,629)	(3,769)	(31,677)	(9,859)
Interest income and other, net	7	137	74	480
Net loss and comprehensive loss	$ (17,622)	$ (3,632)	$ (31,603)	$ (9,379)
Net loss per share attributable to common stockholders—basic and diluted	$ (1.74)	$ (0.36)	$ (3.13)	$ (0.93)
Weighted-average common shares outstanding—basic and diluted	10,109,847	10,091,100	10,099,134	10,091,100

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

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+ Details

Consolidated Statements of Convertible Preferred Stock and Stockholders' Deficit (Unaudited) - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Deficit	Convertible Preferred Stock
Balance at Dec. 31, 2018	$ (36,161)	$ 10	$ 4,008	$ (40,179)
Balance, shares at Dec. 31, 2018					33,645,447
Balance at Dec. 31, 2018					$ 69,114
Balance, shares at Dec. 31, 2018		10,091,100
Stock-based compensation expense	146		146
Net loss	(2,193)			(2,193)
Balance at Mar. 31, 2019	(38,208)	$ 10	4,154	(42,372)
Balance, shares at Mar. 31, 2019					33,645,447
Balance at Mar. 31, 2019					$ 69,114
Balance, shares at Mar. 31, 2019		10,091,100
Balance at Dec. 31, 2018	(36,161)	$ 10	4,008	(40,179)
Balance, shares at Dec. 31, 2018					33,645,447
Balance at Dec. 31, 2018					$ 69,114
Balance, shares at Dec. 31, 2018		10,091,100
Net loss	(9,379)
Balance at Sep. 30, 2019	(45,090)	$ 10	4,458	(49,558)
Balance, shares at Sep. 30, 2019					33,645,447
Balance at Sep. 30, 2019					$ 69,114
Balance, shares at Sep. 30, 2019		10,091,100
Balance at Mar. 31, 2019	(38,208)	$ 10	4,154	(42,372)
Balance, shares at Mar. 31, 2019					33,645,447
Balance at Mar. 31, 2019					$ 69,114
Balance, shares at Mar. 31, 2019		10,091,100
Stock-based compensation expense	147		147
Net loss	(3,554)			(3,554)
Balance at Jun. 30, 2019	(41,615)	$ 10	4,301	(45,926)
Balance, shares at Jun. 30, 2019					33,645,447
Balance at Jun. 30, 2019					$ 69,114
Balance, shares at Jun. 30, 2019		10,091,100
Stock-based compensation expense	157		157
Net loss	(3,632)			(3,632)
Balance at Sep. 30, 2019	(45,090)	$ 10	4,458	(49,558)
Balance, shares at Sep. 30, 2019					33,645,447
Balance at Sep. 30, 2019					$ 69,114
Balance, shares at Sep. 30, 2019		10,091,100
Balance at Dec. 31, 2019	$ (49,571)	$ 10	4,632	(54,213)
Balance, shares at Dec. 31, 2019	33,645,447				33,645,447
Balance at Dec. 31, 2019	$ 69,114				$ 69,114
Balance, shares at Dec. 31, 2019		10,091,100
Stock-based compensation expense	189		189
Net loss	(3,988)			(3,988)
Balance at Mar. 31, 2020	(53,370)	$ 10	4,821	(58,201)
Balance, shares at Mar. 31, 2020					33,645,447
Balance at Mar. 31, 2020					$ 69,114
Balance, shares at Mar. 31, 2020		10,091,100
Balance at Dec. 31, 2019	$ (49,571)	$ 10	4,632	(54,213)
Balance, shares at Dec. 31, 2019	33,645,447				33,645,447
Balance at Dec. 31, 2019	$ 69,114				$ 69,114
Balance, shares at Dec. 31, 2019		10,091,100
Issuance of common stock for exercise of stock options, shares	18,747
Net loss	$ (31,603)
Balance at Sep. 30, 2020	$ (76,511)	$ 10	9,295	(85,816)
Balance, shares at Sep. 30, 2020	48,958,829				48,958,829
Balance at Sep. 30, 2020	$ 175,745				$ 175,745
Balance, shares at Sep. 30, 2020		10,109,847
Balance at Mar. 31, 2020	(53,370)	$ 10	4,821	(58,201)
Balance, shares at Mar. 31, 2020					33,645,447
Balance at Mar. 31, 2020					$ 69,114
Balance, shares at Mar. 31, 2020		10,091,100
Issuance of Series D convertible preferred stock, net of issuance costs of $869					$ 106,631
Issuance of Series D convertible preferred stock, net of issuance costs of $869, shares					15,313,382
Issuance of common stock for exercise of stock options	27		27
Issuance of common stock for exercise of stock options, shares		18,747
Stock-based compensation expense	209		209
Net loss	(9,993)			(9,993)
Balance at Jun. 30, 2020	(63,127)	$ 10	5,057	(68,194)
Balance, shares at Jun. 30, 2020					48,958,829
Balance at Jun. 30, 2020					$ 175,745
Balance, shares at Jun. 30, 2020		10,109,847
Stock-based compensation expense	4,238		4,238
Net loss	(17,622)			(17,622)
Balance at Sep. 30, 2020	$ (76,511)	$ 10	$ 9,295	$ (85,816)
Balance, shares at Sep. 30, 2020	48,958,829				48,958,829
Balance at Sep. 30, 2020	$ 175,745				$ 175,745
Balance, shares at Sep. 30, 2020		10,109,847

Consolidated Statements of Convertible Preferred Stock and Stockholders' Deficit (Unaudited) (Parenthetical) $ in Thousands	3 Months Ended
	Jun. 30, 2020 USD ($)
Series D Convertible Preferred Stock
Stock issuance costs	$ 869

Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Cash flows from operating activities
Net loss			$ (31,603)	$ (9,379)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation expense			4,636	450
Depreciation and amortization expense	$ 5	$ 4	13	13
Changes in operating assets and liabilities:
Prepaid expenses and other current assets			(2,781)	(41)
Accounts payable			3,689	(290)
Accrued expenses and other liabilities			4,259	361
Net cash used in operating activities			(21,787)	(8,886)
Cash flows from investing activities
Additions to property and equipment			(21)	(2)
Net cash used in investing activities			(21)	(2)
Cash flows from financing activities
Proceeds from issuance of convertible preferred stock, net of issuance costs			106,631
Proceeds from issuance of common stock for exercise of stock options			27
Payments of deferred offering costs			(1,128)
Net cash provided by financing activities			105,530
Net increase (decrease) in cash, cash equivalents and restricted cash			83,722	(8,888)
Cash, cash equivalents and restricted cash at the beginning of period			21,768	34,599
Cash, cash equivalents and restricted cash at the end of period	105,490	25,711	105,490	25,711
Cash, cash equivalents and restricted cash at the end of period
Cash and cash equivalents	105,383	25,604	105,383	25,604
Restricted cash	107	107	107	107
Cash, cash equivalents and restricted cash at the end of period	$ 105,490	$ 25,711	105,490	$ 25,711
Supplemental disclosure of noncash financing activities
Equity issuance costs included in accounts payable and accrued expenses			$ 394

Nature of Business

9 Months Ended

Sep. 30, 2020

Organization Consolidation And Presentation Of Financial Statements [Abstract]

Nature of Business

1. Nature of Business

Background

Atea Pharmaceuticals, Inc., together with its subsidiary Atea Pharmaceuticals Securities Corporation, is referred to on a consolidated basis as 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 life-threatening viral infections.

The accompanying unaudited consolidated financial statements are presented as of September 30, 2020 and for the three-month and nine-month periods then ended. As discussed further in Note 13, there were several material events that occurred after September 30, 2020 which are described below:

Series D-1 Convertible Preferred Stock

In October 2020, the Company issued 8,973,261 shares of Series D-1 Convertible Preferred Stock at a purchase price of $11.98 per share for gross proceeds of $107,500 (the “Series D-1 Closing”).

Roche License Agreement

In October 2020, the Company entered into the Roche License Agreement, granting Roche an exclusive license to develop and commercialize AT-527 outside of the United States (other than for certain use in connection with the hepatitis C indication). The Company also granted Roche a global license to manufacture AT-527 and agreed that Roche would manufacture the global commercial supply of AT-527 for uses other than the hepatitis C indication. As part of the consideration, Roche agreed to pay the Company an upfront payment of $350,000 (the “Roche Upfront Payment”), which was received in November 2020.

Initial Public Offering

In November 2020, the Company completed an initial public offering of its common stock (the “IPO”). In connection with the IPO, the Company issued 14,375,000 shares of its common stock, including the exercise in full of the underwriters’ option to purchase up to 1,875,000 shares, at $24.00 per share for aggregate gross proceeds of $345,000 before deducting underwriting discounts and commissions of $24,150 and offering expenses of approximately $3,200. As a result of the IPO, all shares of Series A, B, C, D and D-1 convertible preferred stock converted into 57,932,090 shares of common stock.

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 discover and 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 will require significant amounts of additional capital, additional research and development efforts, including extensive preclinical and clinical testing and 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 is also subject to risks associated with the COVID-19 global pandemic, including actual and potential delays associated with certain of its ongoing and anticipated trials, and potential negative impacts on the Company’s business operations and its ability to raise additional capital to finance its operations.

Through September 30, 2020, the Company financed its operations from the sale of convertible preferred stock. Since its inception, the Company has incurred recurring operating losses and negative cash flows from operations. As of September 30, 2020, the Company had an accumulated deficit of $85,816. The Company expects to continue to generate operating losses for the foreseeable future. The Company believes that its cash and cash equivalents of $105,383 as of September 30, 2020, together with the net proceeds from the Series D-1 Closing, the Roche Upfront Payment and the net proceeds from the IPO will be sufficient to fund its operations as currently planned through at least 2023.

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 additional 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 shareholders.

Summary of Significant Accounting Policies

9 Months Ended

Sep. 30, 2020

Accounting Policies [Abstract]

Summary of Significant Accounting Policies

2. Summary of Significant Accounting Policies

Basis of Presentation and Use of Estimates

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 Securities and Exchange Commission (“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 rules and regulations. Accordingly, these 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, 2019 included in the Company’s final prospectus for its IPO filed pursuant to Rule 424(b)(4) under the Securities Act of 1933, as amended (the “Securities Act”), with the SEC on October 30, 2020.

The preparation of unaudited financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts reported in the 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 and the valuation of common stock in connection with the issuance of stock-based awards. Changes in estimates are recorded in the period in which they become known.

Principles of Consolidation

The unaudited 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.

Unaudited Interim Financial Information

The accompanying consolidated balance sheet as of September 30, 2020, the consolidated statements of operations and comprehensive loss for the three and nine months ended September 30, 2020, the consolidated statements of convertible preferred stock and stockholders’ deficit for the three and nine months ended September 30, 2020 and 2019, and the consolidated statements of cash flows for the nine months ended September 30, 2020 and 2019 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 September 30, 2020, the results of its operations for the three and nine months ended September 30, 2020 and 2019 and its cash flows for the nine months ended September 30, 2020 and 2019. The results for the nine months ended September 30, 2020 are not necessarily indicative of results to be expected for the year ending December 31, 2020, any other interim periods, or any future year or period.

Cash and Cash Equivalents

The Company considers all highly-liquid investments purchased with maturities of 90 days or less at acquisition to be cash equivalents. Cash and cash equivalents include bank demand deposits and money market funds that invest in U.S. government and U.S. government agency obligations. Cash equivalents are reported at fair value.

Concentrations of Credit Risk and Significant Suppliers

Financial instruments that potentially subject the Company to concentrations of credit risk are primarily cash and cash equivalents. The Company maintains its cash and cash equivalents with a financial institution that management believes is creditworthy. The Company’s investment policy includes guidelines on the quality of the financial institutions and financial instruments and defines allowable investments that the Company believes minimizes the exposure to concentration of credit risk.

The Company is dependent on third-party manufacturers to supply products for its research and development activities. In particular, the Company relies and expects to continue to rely on a small number of manufacturers to supply it with its requirements for the active pharmaceutical ingredients and formulated drugs related to its research and development activities. These activities could be adversely affected by a significant interruption in the supply of active pharmaceutical ingredients and formulated drugs.

Fair Value Measurements

Assets and liabilities recorded at fair value on a recurring basis in the balance sheets are categorized based upon the level of judgment associated with the inputs used to measure their fair values. Fair value is defined as the exchange price that would be received for an asset or an exit price that would be paid to transfer a liability in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. Valuation techniques used to measure fair value must maximize the use of observable inputs and minimize the use of unobservable inputs. The authoritative guidance on fair value measurements establishes a three-tier fair value hierarchy for disclosure of fair value measurements as follows:

Level 1—Observable inputs such as unadjusted, quoted prices in active markets for identical assets or liabilities at the measurement date.

Level 2—Observable inputs (other than quoted prices included in Level 1) that are either directly or indirectly observable for the asset or liability. These include quoted prices for similar assets or liabilities in active markets and quoted prices for identical or similar assets or liabilities in markets that are not active.

Level 3—Unobservable inputs that are supported by little or no market activity and that are significant to determination of fair value of the assets or liabilities.

Cash, cash equivalents and restricted cash are Level 1 assets which are comprised of funds held in checking and money market accounts. Cash, cash equivalents and restricted cash were recorded at fair value as disclosed in Note 3. The carrying amounts of accounts payable and accrued expenses approximate their fair values due to their short-term maturities.

Property and Equipment

Property and equipment are stated at cost, less accumulated depreciation and amortization. Property and equipment are depreciated using the straight-line method over the estimated useful lives of the asset. The Company estimates the useful life of its assets as follows:



Asset	Estimated useful life

Laboratory equipment	Five years

Office furniture and fixtures	Five years

Computer hardware	Two years

Leasehold improvements	Shorter of useful life or remaining lease term

Maintenance and repairs that do not improve or extend the life of the respective asset are expensed to operations as incurred. Upon disposal of an asset, the related cost and accumulated depreciation are removed from the accounts and any resulting gain or loss is included in the results of operations.

Other Assets

The Company capitalizes incremental legal, professional, accounting and other third-party fees that are directly associated with its financing activities as deferred financing costs included in other non-current assets until a particular financing is consummated. After consummation of a financing, the applicable costs will be recorded in stockholders’ equity as a reduction of additional paid-in-capital generated as a result of the financing. As of September 30, 2020, IPO-related equity issuance costs of $1,537 were included in Other assets in the accompanying consolidated balance sheet. Also included in Other assets is restricted cash of $107, to collateralize a letter of credit.

Impairment of Long-lived Assets

The Company reviews long-lived assets when events or changes in circumstances indicate the carrying value of the assets may not be recoverable. Recoverability is measured by comparing the book value of the assets to the estimated undiscounted future net cash flows that the asset is expected to generate. If the estimated undiscounted future net cash flows are less than the book value, the asset is impaired, and the impairment loss to be recognized in the statement of operations is measured as the amount by which the book value of the asset exceeds its fair value, which is measured based on the estimated discounted future net cash flows that the asset is expected to generate. No impairment losses were recorded during the three and nine months ended September 30, 2020 and 2019.

Research and Development Costs

Research and development costs are expensed as incurred. Research and development expenses consist principally of costs associated with outsourced research and development activities, including preclinical and clinical development, manufacturing and research conducted by contract research organizations and academic institutions, employee compensation and consulting expenses together with related expenses, professional fees and facility and overhead costs. Facility and overhead costs primarily include the allocation of rent, utility and office-related expenses attributable to research and development personnel. In circumstances where amounts have been paid in advance or in excess of costs incurred, the Company records a prepaid expense, which is expensed as services are performed or goods are delivered.

The Company has entered into various research and development contracts with third parties. These agreements are generally cancelable, and related payments are recorded as research and development expenses as incurred. The Company records accruals for estimated ongoing research costs. When evaluating the adequacy of the accrued liabilities, the Company analyzes progress of the studies, including the phase of completion of events, invoices received and contracted costs. Significant judgments and estimates are made in determining the accrued balances at the end of any reporting period. Actual results could differ from the Company’s estimates. The Company’s historical accrual estimates have not been materially different from the actual costs.

Patent Costs

Costs to secure and maintain the Company’s patents are expensed as incurred and are classified as general and administrative expenses in the Company’s consolidated statements of operations.

Stock-based Compensation

Stock-based compensation expense is classified in the consolidated statement of operations in the same manner in which the award recipient’s payroll costs or service payments are classified. Stock-based awards granted to employees and non-employees are measured based on the estimated fair value of the awards using the Black-Scholes option pricing model (“Black-Scholes”). Stock-based compensation expense with respect to awards with service conditions is recognized using the straight-line method over the service period. Stock-based compensation with respect to awards with performance conditions is recognized when satisfaction of the performance conditions is probable. Stock-based compensation is based on awards ultimately expected to vest and, as such, it is reduced by forfeitures. The Company accounts for forfeitures as they occur.

Black-Scholes requires the use of subjective assumptions which determine the fair value of stock-based awards. These assumptions include:

Fair value of common stock—Through September 30, 2020, because there was no public market for the Company’s common stock, the fair value of the Company’s common stock underlying stock-based awards was estimated on each grant date by the board of directors.

Risk-free interest rate—The risk-free interest rate is based on the U.S. Treasury zero coupon issues in effect at the time of grant for periods corresponding with the expected term of a stock-based award.

Expected term—The expected term represents the period that stock-based awards are expected to be outstanding. Given the Company’s lack of specific history, the expected term for option grants is determined using the simplified method. The simplified method deems the term to be the average of the time-to-vesting and the contractual life of the stock-based awards.

Expected volatility—Since the Company was privately held through September 30, 2020 and did not have any trading history for its common stock, the expected volatility was estimated based on the average volatility for comparable publicly traded biotechnology companies over a period equal to the expected term of the stock-based awards. The comparable companies were chosen based on their similar size, stage in the life cycle or area of specialty. The Company will continue to apply this process until a sufficient amount of historical information regarding the volatility of its own stock price becomes available.

Expected dividend yield —The Company has never paid dividends on its common stock and has no plans to pay dividends on its common stock. Therefore, the Company used an expected dividend yield of zero.

Income Taxes

The Company uses the asset and liability method of accounting for income taxes. Deferred tax assets and liabilities are recognized for the estimated future tax consequences attributable to temporary differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax base. Deferred tax assets, which relate primarily to the carrying amount of the Company’s net operating loss carryforwards, are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. Deferred tax expense or benefit is the result of changes in the deferred tax assets and liabilities. Valuation allowances are established to reduce deferred tax assets where, based upon the available evidence, the Company concludes that it is more-likely-than-not that the deferred tax assets will not be realized. In evaluating its ability to recover deferred tax assets, the Company considers all available positive and negative evidence, including its operating results, ongoing tax planning and forecasts of future taxable income.

Reserves are provided for tax benefits for which realization is uncertain. Such benefits are only recognized when the underlying tax position is considered more-likely-than-not to be sustained on examination by a taxing authority. Interest and penalties related to uncertain tax positions are recognized in the provision of income taxes.

Comprehensive Loss

Comprehensive income (loss) includes net income (loss) as well as other changes in stockholder equity (deficit) that result from transactions and economic events other than those with equity holders. The Company did not have any items of comprehensive income or loss other than net loss for the three and nine months ended September 30, 2020 and 2019.

Net Loss Per Share Attributable to Common Stockholders

The Company calculates basic and diluted net loss per share attributable to common stockholders in conformity with the two-class method required for participating securities. The Company considers its convertible preferred stock to be participating securities as, in the event a dividend is paid on common stock, the holders of convertible preferred stock would be entitled to receive dividends on a basis consistent with the common stockholders. Under the two-class method, the net loss attributable to common stockholders is not allocated to the convertible preferred stock as the holders of the convertible preferred stock do not have a contractual obligation to share in losses.

Since inception, the Company has incurred recurring operating losses and, as such, under the two-class method, basic net loss per share attributable to common stockholders is computed by dividing the net loss attributable to common stockholders by the weighted average number of shares of common stock. Under the two-class method, for periods with net income, basic net income per common share is computed by dividing the net income attributable to common stockholders by the weighted-average number of shares of common stock outstanding during the period. Net income attributable to common stockholders is computed by subtracting from net income the portion of current year earnings that the participating securities would have been entitled to receive pursuant to their dividend rights had all of the year’s earnings been distributed. No such adjustment to earnings is made during periods with a net loss, as the holders of the participating securities have no obligation to fund losses. Diluted net loss per common share is computed by using the weighted-average number of shares of common stock outstanding. Due to net losses for the three and nine months ended September 30, 2020 and 2019, basic and diluted net loss per share attributable to common stockholders were the same, as the effect of all potentially dilutive securities would have been anti-dilutive.

Segments

Operating segments are defined as components of an entity for which separate financial information is available and that is regularly reviewed by the chief operating decision maker (the “CODM”), in deciding how to allocate resources to an individual segment and in assessing performance. The Company’s CODM is its chief executive officer, who manages and allocates resources to the operations on a total company basis. Accordingly, there is a single operating segment and one reportable segment.

Emerging Growth Company Status

The Company is an emerging growth company, as defined in the Jumpstart Our Business Startups Act of 2012 (the “JOBS Act”). Under the JOBS Act, emerging growth companies can delay adopting new or revised accounting standards issued subsequent to the enactment of the JOBS Act, until such time as those standards apply to private companies. The Company has elected to use this extended transition period for complying with new or revised accounting standards that have different effective dates for public and private companies until the earlier of the date that it (i) is no longer an emerging growth company or (ii) affirmatively and irrevocably opts out of the extended transition period provided in the JOBS Act. As a result, these consolidated financial statements may not be comparable to companies that comply with the new or revised accounting pronouncements as of public company effective dates.

Recently Issued Accounting Pronouncements

In February 2016, the Financial Accounting Standards Board (“FASB”) issued ASU No. 2016-02, Leases, which requires a lessee to record a right-of-use asset and a corresponding lease liability on the balance sheet for all leases with terms longer than 12 months. A modified retrospective transition approach is required for lessees for capital and operating leases existing at, or entered into after, the beginning of the earliest comparative period presented in the financial statements, with certain practical expedients available. As the Company has elected to use the extended transition period for complying with new or revised accounting standards as available under the Jobs Act, the standard is effective for the Company beginning January 1, 2021. The Company is currently evaluating the expected impact that the standard could have on its consolidated financial statements and related disclosures.

In July 2017, the FASB issued ASU No. 2017-11, Earnings Per Share (Topic 260), Distinguishing Liabilities from Equity (Topic 480), Derivatives and Hedging (Topic 815) I. Accounting for Certain Financial Instruments with Down Round Features II. Replacement of the Indefinite Deferral for Mandatorily Redeemable Financial Instruments of Certain Nonpublic Entities and Certain Mandatorily Redeemable Noncontrolling Interests with a Scope Exception (“ASU 2017-11”). Part I applies to entities that issue financial instruments such as warrants, convertible debt or convertible preferred stock that contain down-round features. Part II replaces the indefinite deferral for certain mandatorily redeemable noncontrolling interests and mandatorily redeemable financial instruments of nonpublic entities contained within ASC Topic 480 with a scope exception and does not impact the accounting for these mandatorily redeemable instruments. As the Company has elected to use the extended transition period for complying with new or revised accounting standards as available under the Jobs Act, the standard is effective for the Company beginning January 1, 2021, with early adoption permitted. The Company is currently evaluating the expected impact that the standard could have on its consolidated financial statements and related disclosures.

Recently Adopted Accounting Pronouncements

In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606) (“ASU 2014-09”), which supersedes existing revenue recognition guidance under GAAP. The standard’s core principle is that a company will recognize revenue when it transfers promised goods or services to customers in an amount that reflects the consideration to which the company expects to be entitled in exchange for those goods or services. The standard defines a five-step process to achieve this principle and will require companies to use more judgment and make more estimates than under the current guidance. The Company expects that these judgments and estimates will include identifying performance obligations in the customer contract, estimating the amount of variable consideration to include in the transaction price and allocating the transaction price to each separate performance obligation. ASU 2014-09 also requires additional disclosure about the nature, amount, timing and uncertainty of revenue and cash flows arising from customer contracts. In August 2015, the FASB issued ASU No. 2015-14, Revenue from Contracts with Customers (Topic 606): Deferral of the Effective Date, which delays the effective date of ASU 2014-09 such that the standard is effective for annual periods beginning after December 15, 2018. The FASB subsequently issued amendments to ASU 2014-09 that have the same effective date and transition date. The Company adopted ASU 2014-09 as of January 1, 2019 and the adoption did not have an impact on the Company’s consolidated financial statements as the Company did not have any revenue-generating arrangements through September 30, 2020.

In August 2018, the FASB issued ASU 2018-13, Disclosure Framework—Changes to the Disclosure Requirements for Fair Value Measurements, which changes the fair value measurement disclosure requirements of ASC 820. The goal of the ASU is to improve the effectiveness of ASC 820’s disclosure requirements. The standard is applicable to the Company for fiscal years beginning January 1, 2020, and interim periods within those years. The Company elected to early adopt this guidance effective January 1, 2019. The adoption of this guidance did not have an effect the Company’s consolidated financial statements.

Fair Value Measurements

9 Months Ended

Sep. 30, 2020

Fair Value Disclosures [Abstract]

Fair Value Measurements

3. 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 September 30, 2020
	Level 1		Level 2		Level 3		Total
Cash equivalents
Money market funds	$	96,609	$	—	$	—	$	96,609
Total cash equivalents	$	96,609	$	—	$	—	$	96,609

	Fair Value Measurements as of December 31, 2019
	Level 1		Level 2		Level 3		Total
Cash equivalents
Money market funds	$	21,038	$	—	$	—	$	21,038
Total cash equivalents	$	21,038	$	—	$	—	$	21,038

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 consolidated balance sheets as of September 30, 2020 and December 31, 2019.

There were no transfers among Level 1, Level 2 or Level 3 categories in the three and nine months ended September 30, 2020 and 2019.

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

Property and Equipment, net

9 Months Ended

Sep. 30, 2020

Property Plant And Equipment [Abstract]

Property and Equipment, net

4. Property and Equipment, net

Property and equipment, net, consist of the following:

	September 30, 2020			December 31, 2019
Laboratory equipment	$	5		$	5
Office furniture and fixtures		13			13
Computer hardware		32			11
Leasehold improvements		125			125
Total property and equipment, at cost		175			154
Less: accumulated depreciation and amortization		(126	)		(113	)
Property and equipment, net	$	49		$	41

Depreciation and amortization expense was $5 and $4 for the three months ended September 30, 2020 and 2019, respectively. Depreciation and amortization expense was $13 and $13 for the nine months ended September 30, 2020 and 2019, respectively.

Accrued Expenses and Other Current Liabilities

9 Months Ended

Sep. 30, 2020

Payables And Accruals [Abstract]

Accrued Expenses and Other Current Liabilities

5. Accrued Expenses and Other Current Liabilities

Accrued expenses and other current liabilities consist of the following:

	September 30, 2020		December 31, 2019
Research and development	$	4,892	$	1,326
License fees (Note 6)		—		200
Professional fees and other		626		361
Payroll and payroll related		822		—
Total accrued expenses and other current liabilities	$	6,340	$	1,887

Commitments and Contingencies

9 Months Ended

Sep. 30, 2020

Commitments And Contingencies Disclosure [Abstract]

Commitments and Contingencies

6. Commitments and Contingencies

Operating Lease Agreements

The Company leases an office facility under a non-cancelable operating lease that expires July 2022. The office lease includes commitments obligating the Company to pay a pro rata share of certain building operating costs and annual rent escalations which will result in higher lease payments in future years. Rent expense is recognized on a straight-line basis over the term of the lease with the difference between expense and the payments recorded as deferred rent, which is included in accrued expenses and other current liabilities and other liabilities.

As of September 30, 2020, future minimum payments for operating leases are as follows:

2020	$	85
2021		340
2022		200
Total future minimum lease payments	$	625

Rent expense recognized under all operating leases was $70 and $70 for the three months ended September 30, 2020 and 2019, respectively. Rent expense recognized under all operating leases was $211 and $211 for the nine months ended September 30, 2020 and 2019, respectively.

The Company is required to maintain a letter of credit for the duration of the office lease. The Company maintains bank deposits of $107 to collateralize the letter of credit which are classified as restricted cash and a long-term asset in the consolidated balance sheet as of September 30, 2020.

License Agreement with NovaMedica LLC

In May 2014, the Company entered into an exclusive license agreement with NovaMedica LLC, an affiliated entity of a stockholder, pursuant to which the Company granted NovaMedica a license to certain intellectual property rights for commercialization of a potential product for the treatment of hepatitis C. In connection with the license, the Company received a license fee of $200 in partial consideration for the grant of the license. Recognition of the license fee was deferred and recorded in other liabilities pending finalization by the Company and NovaMedica of certain other terms and conditions of the license agreement at which time the technology access fee was to have been evaluated, along with the license agreement broadly, for revenue recognition.

If the Company and NovaMedica failed to agree on the terms of an amendment to the license agreement covering certain terms and conditions, and the license agreement was thereafter terminated, such termination was to be subject to a payment by the Company of a termination fee of $400. This agreement was terminated in May 2020, and the Company paid a termination fee of $400.

Business Development Consulting Agreements

The Company is a party to a consulting agreement that provides for the payment by the Company of consideration, consisting of cash, up to a maximum of $1,750, and the vesting of equity awards, if a business development transaction that meets or exceeds certain thresholds is successfully concluded on or before December 31, 2020 (Note 9). As of September 30, 2020, the performance conditions were not yet probable of being met and, as a result, no expense has yet to be recognized in connection with the consulting agreement in the consolidated statement of operations.

In February 2020, the Company entered into 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 $5,000.

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, (ii) contracts under which the Company must indemnify directors and certain officers and consultants for liabilities arising out of their relationship, 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 them 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 potentially 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.

Convertible Preferred Stock

9 Months Ended

Sep. 30, 2020

Equity [Abstract]

Convertible Preferred Stock

7. Convertible Preferred Stock

In May 2020, the Company filed an amendment to its certificate of incorporation to authorize 15,313,382 shares of Series D convertible preferred stock (“Series D Preferred”) and 8,973,261 shares of Series D-1 convertible preferred stock (“Series D-1 Preferred”). The Company entered into a stock purchase agreement with certain investors and issued 15,313,382 shares of Series D Preferred for gross proceeds of approximately $107,500. The Series D investors had the option to purchase up to 8,973,261 shares of Series D-1 Preferred at a price of $11.98 per share, including 2,991,087 shares which the Series D investors had an obligation to purchase if certain milestones were achieved. The Company concluded that the tranche features were not freestanding financing instruments as the right to purchase the future tranches was not legally detachable from the shares of Series D Preferred. Additionally, the Company concluded that no beneficial conversion features were present at initial issuance. As discussed in Note 13, the Series D investors purchased all 8,973,261 shares of Series D-1 at a price of $11.98 per share for aggregate gross proceeds of $107,500 in October 2020.

As of September 30, 2020, the Company had 57,932,090 shares of convertible preferred stock (“Convertible Preferred Stock”) authorized, of which 20,000,000 shares were designated as Series A convertible preferred stock, (“Series A Preferred”); 7,592,830 shares were designated as Series B convertible preferred stock (“Series B Preferred”); 6,052,617 shares were designated as Series C convertible preferred stock (“Series C Preferred”); 15,313,382 shares were designated as Series D Preferred; and 8,973,261 shares were designated as Series D-1 Preferred. The Company’s Series A Preferred, Series B Preferred, Series C Preferred and Series D Preferred were issued at $1.00, $3.03, $4.56 and $7.02 per share, respectively.

The following table summarizes the Company’s outstanding Convertible Preferred Stock as of September 30, 2020:


	Preferred Stock Authorized		Preferred Stock Issued and Outstanding		Carrying Value		Liquidation Preference		Common Stock Issuable Upon Conversion
Series A Preferred		20,000,000		20,000,000	$	19,136	$	20,000		20,000,000
Series B Preferred		7,592,830		7,592,830		22,619		23,006		7,592,830
Series C Preferred		6,052,617		6,052,617		27,359		27,600		6,052,617
Series D Preferred		15,313,382		15,313,382		106,631		107,500		15,313,382
Series D-1 Preferred		8,973,261		—		—		—		—
		57,932,090		48,958,829	$	175,745	$	178,106		48,958,829

The Company classifies Convertible Preferred Stock outside of stockholders’ deficit because the shares contain deemed liquidation rights in the event of a merger, consolidation, or reorganization involving the Company or a subsidiary or upon the sale, lease, transfer, exclusive license or other disposition by the Company or a subsidiary of all or substantially all assets of the Company that could trigger a distribution of cash or assets and therefore a contingent redemption feature not solely within the Company’s control.

Upon the closing of the Company’s IPO in November 2020, all outstanding Convertible Preferred Stock, including the Series D-1 Preferred issued in October 2020, automatically converted into 57,932,090 shares of common stock.

Common Stock

9 Months Ended

Sep. 30, 2020

Equity [Abstract]

Common Stock

8. Common Stock

At September 30, 2020, the authorized capital of the Company included 80,529,575 shares of common stock, of which 10,109,847 shares of common stock were considered issued and outstanding for accounting purposes. As discussed in Note 9, restricted stock awards for an aggregate of 200,000 shares are excluded from issued and outstanding shares for accounting purposes. On all matters to be voted upon by the holders of common stock, holders of common stock are entitled to one vote per share. The holders of common stock are entitled to receive dividends, when declared by the board, and to share ratably in the Company’s assets legally available for distribution to the holders of the Company’s stock in the event of liquidation subject to the rights and preferences applicable to the outstanding shares of Convertible Preferred Stock prior to the conversion of the Convertible Preferred Stock in November 2020. The holders of common stock have no preemptive, redemption or conversion rights.

The Company had the following reserved shares of common stock:

	September 30,
	2020
Series A Preferred		20,000,000
Series B Preferred		7,592,830
Series C Preferred		6,052,617
Series D Preferred		15,313,382
Outstanding options		7,001,747
Options available for future grant		514,477
		56,475,053

Stock-based Compensation

9 Months Ended

Sep. 30, 2020

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Stock-based Compensation

9. Stock-based Compensation

As of September 30, 2020, the Atea Pharmaceuticals 2013 Equity Incentive Plan, as amended (the “2013 Plan”), provided for the grant of incentive stock options, non-qualified stock options, restricted common stock awards and other awards for up to 10,979,971 shares of common stock to employees, officers, directors and consultants of the Company.

As of September 30, 2020, options to purchase 7,095,494 shares of common stock and 3,370,000 shares of restricted common stock had been granted under the 2013 Plan, and there were 514,477 shares of common stock remaining available for future issuance.

Restricted Common Stock

Restricted stock awards generally include vesting and risk of forfeiture provisions that lapse upon satisfaction of performance conditions or over time periods commencing on the grant date and concluding on the third or fourth anniversary of the grant date. The Company has granted awards totaling 200,000 shares of restricted common stock to a consultant pursuant to the 2013 Plan for consulting and business development services. The consultant paid $1.21 per share and an aggregate of $121 for 100,000 of the shares of restricted common stock in 2016 and $1.24 per share and an aggregate of $124 for 100,000 of the shares of restricted common stock in 2018. These awards of restricted common stock will vest, and the risk of forfeiture will lapse upon satisfaction of performance conditions detailed in each award. As of September 30, 2020, the performance conditions were not yet probable of being met and, as a result, no compensation expense has yet been recognized for these performance-based awards. The unvested and forfeitable common stock as of September 30, 2020, though legally issued, are excluded from issued and outstanding shares for accounting purposes. Amounts received for the unvested and forfeitable common stock totaling $245 are included in additional paid-in capital within stockholders’ deficit in the consolidated balance sheets. At September 30, 2020, total unrecognized compensation expense related to unvested restricted common stock was $370.

Stock Options

The following summarizes stock option activity:

	Number of Shares			Weighted Average Exercise Price Per Share		Weighted Average Remaining Contractual Term (years)		Aggregate Intrinsic Value
Outstanding at January 1, 2020		3,911,633		$	1.50		8.5	$	3,915
Granted		3,408,861		$	6.38
Exercised		(18,747	)	$	1.43
Cancelled		(300,000	)	$	6.83
Outstanding at September 30, 2020		7,001,747		$	3.65		8.7	$	22,406
Options exercisable at September 30, 2020		2,857,918		$	1.47		7.4	$	15,371
Vested or expected to vest at September 30, 2020		7,001,747		$	3.65		8.7	$	22,406

The aggregate intrinsic value of options granted is calculated as the difference between the exercise price of the options and the estimated fair value of the Company’s common stock for those options that had exercise prices lower than the fair value of the Company’s common stock.

Option grants generally vest over a service period of three or four years and have a contractual term of ten years. As of September 30, 2020, total unrecognized compensation expense related to stock option awards was $14,923, which amount is being recognized over a remaining weighted average period of 3.7 years.

Stock-based Compensation Expense

Stock-based compensation expense is classified as follows:

	Three Months Ended September 30,				Nine Months Ended September 30,
	2020		2019		2020		2019
Research and development expense	$	2,469	$	63	$	2,627	$	188
General and administrative		1,769		94		2,009		262
Total stock-based compensation expense	$	4,238	$	157	$	4,636	$	450

Net Loss Per Share Attributable to Common Stockholders

9 Months Ended

Sep. 30, 2020

Earnings Per Share [Abstract]

Net Loss Per Share Attributable to Common Stockholders

10. Net Loss Per Share Attributable to Common Stockholders

The following outstanding potentially dilutive shares have been excluded from the calculation of diluted net loss per share, as their effect is anti-dilutive:

	Three Months Ended September 30,				Nine Months Ended September 30,
	2020		2019		2020		2019
Convertible Preferred Stock		48,958,829		33,645,447		48,958,829		33,645,447
Stock options to purchase common stock		7,001,747		3,011,891		7,001,747		3,011,891
Non-vested restricted stock		200,000		200,000		200,000		200,000

Income Taxes

9 Months Ended

Sep. 30, 2020

Income Tax Disclosure [Abstract]

Income Taxes

11. Income Taxes

The Company incurred net operating losses and recorded a full valuation allowance against net deferred tax assets for all periods presented. Accordingly, the Company has not recorded a provision for federal or state income taxes.

- Definition

The entire disclosure for income taxes. Disclosures may include net deferred tax liability or asset recognized in an enterprise's statement of financial position, net change during the year in the total valuation allowance, approximate tax effect of each type of temporary difference and carryforward that gives rise to a significant portion of deferred tax liabilities and deferred tax assets, utilization of a tax carryback, and tax uncertainties information.

+ References + Details

Related Party Transactions

9 Months Ended

Sep. 30, 2020

Related Party Transactions

12. Related Party Transactions

The Company recorded expense of $3 and $34 for the three months ended September 30, 2020 and 2019, respectively, for consulting services provided by an entity affiliated with its former interim Chief Financial Officer. This expense was $43 and $34 for the nine months ended September 30, 2020 and 2019, respectively.

Except as disclosed in Note 6 in the notes to the accompanying consolidated financial statements, there were no other material transactions with related parties.

Subsequent Events

9 Months Ended

Sep. 30, 2020

Subsequent Events [Abstract]

Subsequent Events

13. Subsequent Events

Series D-1 Convertible Preferred Stock

The holders of the Series D Preferred had an option to purchase up to 8,973,261 shares of Series D-1 Preferred at a price of $11.98 per share. In October 2020, the investors exercised their option in full resulting in the issuance of 8,973,261 shares of Series D-1 Preferred at a purchase price of $11.98 per share for aggregate gross proceeds of $107,500.

Roche License Agreement

In October 2020, the Company entered into a license agreement, (the “Roche License Agreement”) with F. Hoffmann-La Roche Ltd and Genentech, Inc. (collectively “Roche”), granting Roche an exclusive license to develop and commercialize AT-527 outside of the United States for all indications other than HCV.

The Company is responsible for completing certain ongoing non-clinical and clinical activities at its own expense and supplying certain clinical trial material under the Roche License Agreement. The parties will work collaboratively on a global development plan intended to support regulatory approval and will share joint development costs equally.

In connection with the Roche License Agreement, Roche paid the Company an upfront payment of $350,000. The License Agreement further provides that Roche is obligated to pay the Company up to an additional $330,000 in the aggregate upon the achievement of certain development and regulatory milestone events; up to an additional $320,000 in the aggregate upon the achievement of certain sales based milestone events and tiered royalties based on annual net sales of the products covered by the Roche License Agreement, ranging between low double-digit and mid-twenties, subject to certain adjustments and limitations. Roche has the right to terminate the Roche License Agreement for convenience pursuant to the terms of the agreement.

In connection with the Roche License Agreement, the Company became obligated to pay a $7,000 fee to a financial advisor for their services. The fee was paid in December 2020.

Initial Public Offering

In November 2020, the Company completed its IPO and issued 14,375,000 shares of its common stock, including the exercise in full of the underwriters’ option to purchase up to 1,875,000 shares at $24.00 per share for aggregate gross proceeds of $345,000 before deducting underwriting discounts and commissions of $24,150 and offering expenses of approximately $3,200. In connection with the IPO, all shares of Series A, B, C, D and D-1 Preferred converted into 57,932,090 shares of common stock. In addition, the Company filed a restated certificate of incorporation to increase the authorized number of shares of common stock to 300,000,000 shares and authorize 10,000,000 shares of undesignated preferred stock that may be issued from time to time by the Company’s board of directors in one or more series.

2020 Plans

In October 2020, the Company’s shareholders approved the Company’s 2020 Incentive Award Plan (the “2020 Plan”), which became effective on October 29, 2020. The 2020 Plan provides for the issuance of up to 7,924,000 shares of common stock.

In October 2020, the Company’s shareholders approved the 2020 Employee Stock Purchase Plan (the “ESPP”), which became effective on October 29, 2020. The ESPP provides for the issuance of up to 1,187,000 shares of common stock.

Summary of Significant Accounting Policies (Policies)

9 Months Ended

Sep. 30, 2020

Accounting Policies [Abstract]

Basis of Presentation and Use of Estimates

Principles of Consolidation

Unaudited Interim Financial Information and Emerging Growth Company Status

Unaudited Interim Financial Information

Emerging Growth Company Status

Cash and Cash Equivalents

Concentrations of Credit Risk and Significant Suppliers

Fair Value Measurements

Level 1—Observable inputs such as unadjusted, quoted prices in active markets for identical assets or liabilities at the measurement date.

Level 3—Unobservable inputs that are supported by little or no market activity and that are significant to determination of fair value of the assets or liabilities.

Property and Equipment



Asset	Estimated useful life

Laboratory equipment	Five years

Office furniture and fixtures	Five years

Computer hardware	Two years

Leasehold improvements	Shorter of useful life or remaining lease term

Other Assets

Impairment of Long-lived Assets

Research and Development Costs

Patent Costs

Costs to secure and maintain the Company’s patents are expensed as incurred and are classified as general and administrative expenses in the Company’s consolidated statements of operations.

Stock-based Compensation

Black-Scholes requires the use of subjective assumptions which determine the fair value of stock-based awards. These assumptions include:

Income Taxes

Comprehensive Loss

Net Loss Per Share Attributable to Common Stockholders

Segments

Recently Issued Accounting Pronouncements and Recently Adopted Accounting Pronouncements

Recently Issued Accounting Pronouncements

Recently Adopted Accounting Pronouncements

Summary of Significant Accounting Policies (Tables)

9 Months Ended

Sep. 30, 2020

Accounting Policies [Abstract]

Schedule of Estimated Useful Life



Asset	Estimated useful life

Laboratory equipment	Five years

Office furniture and fixtures	Five years

Computer hardware	Two years

Leasehold improvements	Shorter of useful life or remaining lease term

Fair Value Measurements (Tables)

9 Months Ended

Sep. 30, 2020

Fair Value Disclosures [Abstract]

Schedule of Financial Assets Measured at Fair Value on Recurring Basis

	Fair Value Measurements as of September 30, 2020
	Level 1		Level 2		Level 3		Total
Cash equivalents
Money market funds	$	96,609	$	—	$	—	$	96,609
Total cash equivalents	$	96,609	$	—	$	—	$	96,609

	Fair Value Measurements as of December 31, 2019
	Level 1		Level 2		Level 3		Total
Cash equivalents
Money market funds	$	21,038	$	—	$	—	$	21,038
Total cash equivalents	$	21,038	$	—	$	—	$	21,038

Property and Equipment, net (Tables)

9 Months Ended

Sep. 30, 2020

Property Plant And Equipment [Abstract]

Summary of Property and Equipment, Net

Property and equipment, net, consist of the following:

	September 30, 2020			December 31, 2019
Laboratory equipment	$	5		$	5
Office furniture and fixtures		13			13
Computer hardware		32			11
Leasehold improvements		125			125
Total property and equipment, at cost		175			154
Less: accumulated depreciation and amortization		(126	)		(113	)
Property and equipment, net	$	49		$	41

Accrued Expenses and Other Current Liabilities (Tables)

9 Months Ended

Sep. 30, 2020

Payables And Accruals [Abstract]

Schedule of Accrued Expenses and Other Current Liabilities

Accrued expenses and other current liabilities consist of the following:

	September 30, 2020		December 31, 2019
Research and development	$	4,892	$	1,326
License fees (Note 6)		—		200
Professional fees and other		626		361
Payroll and payroll related		822		—
Total accrued expenses and other current liabilities	$	6,340	$	1,887

Commitments and Contingencies (Tables)

9 Months Ended

Sep. 30, 2020

Commitments And Contingencies Disclosure [Abstract]

Summary of Future Minimum Payments for Operating Leases

As of September 30, 2020, future minimum payments for operating leases are as follows:

2020	$	85
2021		340
2022		200
Total future minimum lease payments	$	625

Convertible Preferred Stock (Tables)

9 Months Ended

Sep. 30, 2020

Equity [Abstract]

Summary of Outstanding Convertible Preferred Stock

The following table summarizes the Company’s outstanding Convertible Preferred Stock as of September 30, 2020:


	Preferred Stock Authorized		Preferred Stock Issued and Outstanding		Carrying Value		Liquidation Preference		Common Stock Issuable Upon Conversion
Series A Preferred		20,000,000		20,000,000	$	19,136	$	20,000		20,000,000
Series B Preferred		7,592,830		7,592,830		22,619		23,006		7,592,830
Series C Preferred		6,052,617		6,052,617		27,359		27,600		6,052,617
Series D Preferred		15,313,382		15,313,382		106,631		107,500		15,313,382
Series D-1 Preferred		8,973,261		—		—		—		—
		57,932,090		48,958,829	$	175,745	$	178,106		48,958,829

Common Stock (Tables)

9 Months Ended

Sep. 30, 2020

Equity [Abstract]

Summary of Reserved Shares of Common Stock

The Company had the following reserved shares of common stock:

	September 30,
	2020
Series A Preferred		20,000,000
Series B Preferred		7,592,830
Series C Preferred		6,052,617
Series D Preferred		15,313,382
Outstanding options		7,001,747
Options available for future grant		514,477
		56,475,053

- Definition

Tabular disclosure of an entity's stock, including par or stated value per share, number and dollar amount of share subscriptions, shares authorized, shares issued, shares outstanding, number and dollar amount of shares held in an employee trust, dividend per share, total dividends, share conversion features, par value plus additional paid in capital, the value of treasury stock and other information necessary to a fair presentation, and EPS information. Stock by class includes common, convertible, and preferred stocks which are not redeemable or redeemable solely at the option of the issuer. Includes preferred stock with redemption features that are solely within the control of the issuer and mandatorily redeemable stock if redemption is required to occur only upon liquidation or termination of the reporting entity. If more than one issue is outstanding, state the title of each issue and the corresponding dollar amount; dollar amount of any shares subscribed but unissued and the deduction of subscriptions receivable there from; number of shares authorized, issued, and outstanding.

+ References

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+ Details

Stock-based Compensation (Tables)

9 Months Ended

Sep. 30, 2020

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Summary of Stock Options Activity

The following summarizes stock option activity:

	Number of Shares			Weighted Average Exercise Price Per Share		Weighted Average Remaining Contractual Term (years)		Aggregate Intrinsic Value
Outstanding at January 1, 2020		3,911,633		$	1.50		8.5	$	3,915
Granted		3,408,861		$	6.38
Exercised		(18,747	)	$	1.43
Cancelled		(300,000	)	$	6.83
Outstanding at September 30, 2020		7,001,747		$	3.65		8.7	$	22,406
Options exercisable at September 30, 2020		2,857,918		$	1.47		7.4	$	15,371
Vested or expected to vest at September 30, 2020		7,001,747		$	3.65		8.7	$	22,406

Schedule of Stock-based Compensation Expense

Stock-based compensation expense is classified as follows:

	Three Months Ended September 30,				Nine Months Ended September 30,
	2020		2019		2020		2019
Research and development expense	$	2,469	$	63	$	2,627	$	188
General and administrative		1,769		94		2,009		262
Total stock-based compensation expense	$	4,238	$	157	$	4,636	$	450

Net Loss Per Share Attributable to Common Stockholders (Tables)

9 Months Ended

Sep. 30, 2020

Earnings Per Share [Abstract]

Summary of Outstanding Anti-dilutive Shares Excluded from Calculation of Diluted Net Loss Per Share

The following outstanding potentially dilutive shares have been excluded from the calculation of diluted net loss per share, as their effect is anti-dilutive:

	Three Months Ended September 30,				Nine Months Ended September 30,
	2020		2019		2020		2019
Convertible Preferred Stock		48,958,829		33,645,447		48,958,829		33,645,447
Stock options to purchase common stock		7,001,747		3,011,891		7,001,747		3,011,891
Non-vested restricted stock		200,000		200,000		200,000		200,000

Nature of Business - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands		1 Months Ended		9 Months Ended
	Nov. 03, 2020	Nov. 30, 2020	Oct. 31, 2020	Sep. 30, 2020	Dec. 31, 2019	Sep. 30, 2019
Nature of Business [Line Items]
Shares issued				48,958,829	33,645,447
Gross proceeds from issuance of preferred stock				$ 106,631
Convertible preferred stock converted into shares				48,958,829
Accumulated deficit				$ 85,816	$ 54,213
Cash and cash equivalents				$ 105,383	$ 21,661	$ 25,604
Subsequent Event \| IPO
Nature of Business [Line Items]
Share price	$ 24.00	$ 24.00
Aggregated gross proceeds from initial public offering ("IPO")	$ 345,000	$ 345,000
Underwriting discounts and commissions	24,150	24,150
Offering expenses	$ 3,200	$ 3,200
Subsequent Event \| IPO \| Common Stock
Nature of Business [Line Items]
Shares issued	14,375,000	14,375,000
Subsequent Event \| Over-Allotment Option \| Maximum
Nature of Business [Line Items]
Shares issued	1,875,000	1,875,000
Subsequent Event \| Roche License Agreement
Nature of Business [Line Items]
Upfront payment received		$ 350,000
Series D-1 Convertible Preferred Stock \| Subsequent Event
Nature of Business [Line Items]
Shares issued			8,973,261
Share price			$ 11.98
Gross proceeds from issuance of preferred stock			$ 107,500
Series A, B, C, D and D-1 Convertible Preferred Stock \| Subsequent Event \| IPO \| Common Stock
Nature of Business [Line Items]
Convertible preferred stock converted into shares	57,932,090	57,932,090

Summary of Significant Accounting Policies - Schedule of Estimated Useful Life (Details)	9 Months Ended
	Sep. 30, 2020
Laboratory Equipment
Property Plant And Equipment [Line Items]
Estimated useful life	5 years
Office Furniture and Fixtures
Property Plant And Equipment [Line Items]
Estimated useful life	5 years
Computer Hardware
Property Plant And Equipment [Line Items]
Estimated useful life	2 years
Leasehold Improvements
Property Plant And Equipment [Line Items]
Estimated useful life	Shorter of useful life or remaining lease term

Summary of Significant Accounting Policies - Additional Information (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2020 USD ($)	Sep. 30, 2019 USD ($)	Sep. 30, 2020 USD ($) Segment	Sep. 30, 2019 USD ($)
Accounting Policies [Line Items]
Restricted cash	$ 107,000	$ 107,000	$ 107,000	$ 107,000
Impairment losses	0	0	$ 0	0
Expected dividend yield			0.00%
Comprehensive income or loss	0	$ 0	$ 0	$ 0
Number of reportable segments \| Segment			1
Other Assets
Accounting Policies [Line Items]
Restricted cash	107,000		$ 107,000
Other Assets \| IPO
Accounting Policies [Line Items]
Equity issuance costs	$ 1,537,000		$ 1,537,000

Fair Value Measurements - Schedule of Financial Assets Measured at Fair Value on Recurring Basis (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Cash equivalents
Total cash equivalents	$ 96,609	$ 21,038
Level 1
Cash equivalents
Total cash equivalents	96,609	21,038
Money Market Funds
Cash equivalents
Total cash equivalents	96,609	21,038
Money Market Funds \| Level 1
Cash equivalents
Total cash equivalents	$ 96,609	$ 21,038

Property and Equipment, Net - Summary of Property and Equipment, Net (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Property Plant And Equipment [Line Items]
Total property and equipment, at cost	$ 175	$ 154
Less: accumulated depreciation and amortization	(126)	(113)
Property and equipment, net	49	41
Laboratory Equipment
Property Plant And Equipment [Line Items]
Total property and equipment, at cost	5	5
Office Furniture and Fixtures
Property Plant And Equipment [Line Items]
Total property and equipment, at cost	13	13
Computer Hardware
Property Plant And Equipment [Line Items]
Total property and equipment, at cost	32	11
Leasehold Improvements
Property Plant And Equipment [Line Items]
Total property and equipment, at cost	$ 125	$ 125

Property and Equipment, Net - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Property Plant And Equipment [Abstract]
Depreciation and amortization expense	$ 5	$ 4	$ 13	$ 13

Accrued Expenses and Other Current Liabilities - Schedule of Accrued Expenses and Other Current Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Payables And Accruals [Abstract]
Research and development	$ 4,892	$ 1,326
License fees (Note 6)		200
Professional fees and other	626	361
Payroll and payroll related	822
Total accrued expenses and other current liabilities	$ 6,340	$ 1,887

Commitments and Contingencies - Additional Information (Details) - USD ($)	1 Months Ended				3 Months Ended		9 Months Ended
	Dec. 31, 2020	May 31, 2020	Feb. 29, 2020	May 31, 2014	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Loss Contingencies [Line Items]
Lease expiration date							Jul. 31, 2022
Rent expense					$ 70,000	$ 70,000	$ 211,000	$ 211,000
Restricted cash					107,000	$ 107,000	107,000	$ 107,000
License Agreement \| NovaMedica LLC
Loss Contingencies [Line Items]
License fee received				$ 200,000
Termination fee payable upon termination of agreement				$ 400,000
Payment for termination fee		$ 400,000
Business Development Consulting Agreements
Loss Contingencies [Line Items]
Expense recognized							0
Business Development Consulting Agreements \| Maximum
Loss Contingencies [Line Items]
Success fee			$ 5,000,000
Business Development Consulting Agreements \| Maximum \| Forecast
Loss Contingencies [Line Items]
Consideration payable upon achievement of objectives	$ 1,750,000
Other Assets \| Letter of Credit
Loss Contingencies [Line Items]
Restricted cash					$ 107,000		$ 107,000

Commitments and Contingencies - Summary of Future Minimum Payments for Operating Leases (Details) $ in Thousands	Sep. 30, 2020 USD ($)
Operating Lease Liabilities Payments Due [Abstract]
2020	$ 85
2021	340
2022	200
Total future minimum lease payments	$ 625

Convertible Preferred Stock - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended		9 Months Ended
	Oct. 31, 2020	May 31, 2020	Sep. 30, 2020	Nov. 30, 2020	Nov. 03, 2020	Dec. 31, 2019
Class Of Stock [Line Items]
Shares authorized			57,932,090			33,645,447
Shares issued			48,958,829			33,645,447
Gross proceeds from issuance of preferred stock			$ 106,631
Convertible preferred stock converted into shares			48,958,829
Subsequent Event \| IPO
Class Of Stock [Line Items]
Preferred stock purchase price				$ 24.00	$ 24.00
Series D Preferred
Class Of Stock [Line Items]
Shares authorized		15,313,382	15,313,382
Shares issued		15,313,382	15,313,382
Gross proceeds from issuance of preferred stock		$ 107,500
Preferred stock purchase price			$ 7.02
Convertible preferred stock converted into shares			15,313,382
Series D-1 Preferred
Class Of Stock [Line Items]
Shares authorized		8,973,261	8,973,261
Right to purchase price, per share		$ 11.98
Number of shares obligated to purchase upon milestone		2,991,087
Series D-1 Preferred \| Subsequent Event
Class Of Stock [Line Items]
Shares issued	8,973,261
Gross proceeds from issuance of preferred stock	$ 107,500
Preferred stock purchase price	$ 11.98
Series D-1 Preferred \| Subsequent Event \| Maximum
Class Of Stock [Line Items]
Options to purchase shares	8,973,261
Convertible Preferred Stock
Class Of Stock [Line Items]
Shares authorized			57,932,090
Series A Preferred
Class Of Stock [Line Items]
Shares authorized			20,000,000
Shares issued			20,000,000
Preferred stock purchase price			$ 1.00
Convertible preferred stock converted into shares			20,000,000
Series B Preferred
Class Of Stock [Line Items]
Shares authorized			7,592,830
Shares issued			7,592,830
Preferred stock purchase price			$ 3.03
Convertible preferred stock converted into shares			7,592,830
Series C Preferred
Class Of Stock [Line Items]
Shares authorized			6,052,617
Shares issued			6,052,617
Preferred stock purchase price			$ 4.56
Convertible preferred stock converted into shares			6,052,617
Common Stock \| Subsequent Event \| IPO
Class Of Stock [Line Items]
Convertible preferred stock converted into shares				57,932,090

Convertible Preferred Stock - Summary of Outstanding Convertible Preferred Stock (Details) - USD ($) $ in Thousands	Sep. 30, 2020	May 31, 2020	Dec. 31, 2019
Class Of Stock [Line Items]
Preferred Stock Authorized	57,932,090		33,645,447
Preferred Stock Issued	48,958,829		33,645,447
Preferred Stock Outstanding	48,958,829		33,645,447
Carrying Value	$ 175,745
Liquidation Preference	$ 178,106		$ 70,606
Common Stock Issuable Upon Conversion	48,958,829
Series A Preferred
Class Of Stock [Line Items]
Preferred Stock Authorized	20,000,000
Preferred Stock Issued	20,000,000
Preferred Stock Outstanding	20,000,000
Carrying Value	$ 19,136
Liquidation Preference	$ 20,000
Common Stock Issuable Upon Conversion	20,000,000
Series B Preferred
Class Of Stock [Line Items]
Preferred Stock Authorized	7,592,830
Preferred Stock Issued	7,592,830
Preferred Stock Outstanding	7,592,830
Carrying Value	$ 22,619
Liquidation Preference	$ 23,006
Common Stock Issuable Upon Conversion	7,592,830
Series C Preferred
Class Of Stock [Line Items]
Preferred Stock Authorized	6,052,617
Preferred Stock Issued	6,052,617
Preferred Stock Outstanding	6,052,617
Carrying Value	$ 27,359
Liquidation Preference	$ 27,600
Common Stock Issuable Upon Conversion	6,052,617
Series D Preferred
Class Of Stock [Line Items]
Preferred Stock Authorized	15,313,382	15,313,382
Preferred Stock Issued	15,313,382	15,313,382
Preferred Stock Outstanding	15,313,382
Carrying Value	$ 106,631
Liquidation Preference	$ 107,500
Common Stock Issuable Upon Conversion	15,313,382
Series D-1 Preferred
Class Of Stock [Line Items]
Preferred Stock Authorized	8,973,261	8,973,261

Common Stock - Additional Information (Details) - shares	9 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
Class Of Stock [Line Items]
Common stock, shares authorized	80,529,575	53,070,161
Common stock, shares issued	10,109,847	10,091,100
Common stock, shares outstanding	10,109,847	10,091,100
Common stock voting rights per share	On all matters to be voted upon by the holders of common stock, holders of common stock are entitled to one vote per share.
Restricted Stock \| Consultant \| 2013 Equity Incentive Plan
Class Of Stock [Line Items]
Shares excluded from issued and outstanding	200,000

Common Stock - Summary of Reserved Shares of Common Stock (Details)	Sep. 30, 2020 shares
Class Of Stock [Line Items]
Common stock, capital shares reserved for future issuance	56,475,053
Series A Preferred
Class Of Stock [Line Items]
Common stock, capital shares reserved for future issuance	20,000,000
Series B Preferred
Class Of Stock [Line Items]
Common stock, capital shares reserved for future issuance	7,592,830
Series C Preferred
Class Of Stock [Line Items]
Common stock, capital shares reserved for future issuance	6,052,617
Series D Preferred
Class Of Stock [Line Items]
Common stock, capital shares reserved for future issuance	15,313,382
Outstanding options
Class Of Stock [Line Items]
Common stock, capital shares reserved for future issuance	7,001,747
Options available for future grant
Class Of Stock [Line Items]
Common stock, capital shares reserved for future issuance	514,477

Stock-based Compensation - Additional Information (Details) - USD ($)	3 Months Ended		9 Months Ended		12 Months Ended		36 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2018	Dec. 31, 2016	Dec. 31, 2018
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock, capital shares reserved for future issuance	56,475,053		56,475,053
Share-based compensation expense	$ 4,238,000	$ 157,000	$ 4,636,000	$ 450,000
Unrecognized compensation expense	$ 14,923,000		$ 14,923,000
Remaining weighted average period for recognize compensation expense			3 years 8 months 12 days
Stock Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting contractual term			10 years
2013 Equity Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock, capital shares reserved for future issuance	514,477		514,477
2013 Equity Incentive Plan \| Common Stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares, granted	7,095,494		7,095,494
2013 Equity Incentive Plan \| Restricted Stock \| Consultant
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares, granted					100,000	100,000	200,000
Price paid per share					$ 1.24	$ 1.21	$ 1.24
Aggregate amount received for shares					$ 124,000	$ 121,000
Total amounts received for unvested and forfeitable common stock			$ 245,000
2013 Equity Incentive Plan \| Restricted Stock \| Common Stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares, granted	3,370,000		3,370,000
2013 Equity Incentive Plan \| Performance-based Awards
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation expense			$ 0
2013 Equity Incentive Plan \| Non-vested Restricted Common Stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized compensation expense	$ 370,000		$ 370,000
Minimum \| Stock Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting service period			3 years
Maximum \| Stock Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting service period			4 years
Maximum \| 2013 Equity Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares available for grant	10,979,971		10,979,971

Stock-based Compensation - Summary of Stock Options Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
Number of Shares
Number of Shares, Outstanding	3,911,633
Number of Shares, Granted	3,408,861
Number of Shares, Exercised	(18,747)
Number of Shares, Cancelled	(300,000)
Number of Shares, Outstanding	7,001,747	3,911,633
Number of Shares, Options exercisable	2,857,918
Number of Shares, Vested or expected to vest	7,001,747
Weighted Average Exercise Price Per Share
Weighted Average Exercise Price Per Share, Outstanding	$ 1.50
Weighted Average Exercise Price Per Share, Granted	6.38
Weighted Average Exercise Price Per Share, Exercised	1.43
Weighted Average Exercise Price Per Share, Cancelled	6.83
Weighted Average Exercise Price Per Share, Outstanding	3.65	$ 1.50
Weighted Average Exercise Price Per Share, Options exercisable	1.47
Weighted Average Exercise Price Per Share, Vested or expected to vest	$ 3.65
Weighted Average Remaining Contractual Term and Aggregate Intrinsic Value
Weighted Average Remaining Contractual Term (years), Outstanding	8 years 8 months 12 days	8 years 6 months
Weighted Average Remaining Contractual Term (years), Options exercisable	7 years 4 months 24 days
Weighted Average Remaining Contractual Term (years), Vested or expected to vest	8 years 8 months 12 days
Aggregate Intrinsic Value, Outstanding	$ 22,406	$ 3,915
Aggregate Intrinsic Value, Options exercisable	15,371
Aggregate Intrinsic Value, Vested or expected to vest	$ 22,406

Stock-based Compensation - Stock-based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation expense	$ 4,238	$ 157	$ 4,636	$ 450
Research and Development Expense
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation expense	2,469	63	2,627	188
General and Administrative
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation expense	$ 1,769	$ 94	$ 2,009	$ 262

Net Loss Per Share Attributable to Common Stockholders - Summary of Outstanding Anti-dilutive Shares Excluded from Calculation of Diluted Net Loss Per Share (Details) - shares	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Convertible Preferred Stock
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive shares excluded from calculation of diluted net loss per share	48,958,829	33,645,447	48,958,829	33,645,447
Stock Options to Purchase Common Stock
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive shares excluded from calculation of diluted net loss per share	7,001,747	3,011,891	7,001,747	3,011,891
Non-vested Restricted Stock
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive shares excluded from calculation of diluted net loss per share	200,000	200,000	200,000	200,000

Income Taxes - Additional Information (Details)	9 Months Ended
Income Taxes - Additional Information (Details)	Sep. 30, 2020 USD ($)
Income Tax Disclosure [Abstract]
Provision for federal income taxes	$ 0
Provision for state income taxes	$ 0

Related Party Transactions - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Consulting Services \| Former Chief Financial Officer
Related Party Transaction [Line Items]
Related party transaction expense	$ 3	$ 34	$ 43	$ 34

Subsequent Events - Additional Information (Details) - USD ($)		1 Months Ended				9 Months Ended
	Nov. 03, 2020	Dec. 31, 2020	Nov. 30, 2020	Oct. 31, 2020	May 31, 2020	Sep. 30, 2020	Dec. 31, 2019
Subsequent Event [Line Items]
Shares issued						48,958,829	33,645,447
Gross proceeds from issuance of preferred stock						$ 106,631,000
Convertible preferred stock converted into shares						48,958,829
Common stock, shares authorized						80,529,575	53,070,161
Roche License Agreement \| Scenario Forecast
Subsequent Event [Line Items]
Financial advisor fee paid		$ 7,000,000
Subsequent Event
Subsequent Event [Line Items]
Common stock, shares authorized			300,000,000
Subsequent Event \| 2020 Incentive Award Plan
Subsequent Event [Line Items]
Common stock, shares authorized				7,924,000
Stock option plan, effective date				Oct. 29, 2020
Subsequent Event \| 2020 Employee Stock Purchase Plan
Subsequent Event [Line Items]
Common stock, shares authorized				1,187,000
Stock option plan, effective date				Oct. 29, 2020
Subsequent Event \| IPO
Subsequent Event [Line Items]
Share price	$ 24.00		$ 24.00
Aggregated gross proceeds from initial public offering ("IPO")	$ 345,000,000		$ 345,000,000
Underwriting discounts and commissions	24,150,000		24,150,000
Offering expenses	$ 3,200,000		$ 3,200,000
Subsequent Event \| Common Stock \| IPO
Subsequent Event [Line Items]
Shares issued	14,375,000		14,375,000
Subsequent Event \| Undesignated Preferred Stock
Subsequent Event [Line Items]
Preferred stock, shares authorized			10,000,000
Subsequent Event \| Roche License Agreement
Subsequent Event [Line Items]
Upfront payment received			$ 350,000,000
Maximum \| Subsequent Event \| Over-Allotment Option
Subsequent Event [Line Items]
Shares issued	1,875,000		1,875,000
Maximum \| Subsequent Event \| Roche License Agreement \| Development and Regulatory
Subsequent Event [Line Items]
Milestones receivable upon achievement aggregate				$ 330,000,000
Maximum \| Subsequent Event \| Roche License Agreement \| Sales Based
Subsequent Event [Line Items]
Milestones receivable upon achievement aggregate				$ 320,000,000
Series D-1 Preferred Stock
Subsequent Event [Line Items]
Right to purchase price, per share					$ 11.98
Series D-1 Preferred Stock \| Subsequent Event
Subsequent Event [Line Items]
Shares issued				8,973,261
Share price				$ 11.98
Gross proceeds from issuance of preferred stock				$ 107,500,000
Series D-1 Preferred Stock \| Maximum
Subsequent Event [Line Items]
Options to purchase shares					8,973,261
Series A, B, C, D and D-1 Convertible Preferred Stock \| Subsequent Event \| Common Stock \| IPO
Subsequent Event [Line Items]
Convertible preferred stock converted into shares	57,932,090		57,932,090