Athira Pharma (ATHA) S-1 19 Jan 21 IPO registration Financial data

Document and Entity Information

Document and Entity Information	9 Months Ended
	Sep. 30, 2020
Document Information [Line Items]
Document Type	S-1
Amendment Flag	false
Entity Registrant Name	ATHIRA PHARMA, INC.
Entity Central Index Key	0001620463
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	45-3368487
Entity Primary SIC Number	2836
Entity Address, Address Line One	18706 North Creek Parkway
Entity Address, Address Line Two	Suite 104
Entity Address, City or Town	Bothell
Entity Address, State or Province	WA
Entity Address, Postal Zip Code	98011
City Area Code	206
Local Phone Number	221-8112
Business Contact
Document Information [Line Items]
Contact Personnel Name	Leen Kawas, Ph.D.
Entity Address, Address Line One	18706 North Creek Parkway
Entity Address, Address Line Two	Suite 104
Entity Address, City or Town	Bothell
Entity Address, State or Province	WA
Entity Address, Postal Zip Code	98011
City Area Code	206
Local Phone Number	221-8112

Balance Sheets

Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 165,725	$ 2,056	$ 3,317
Short-term investments	60,547		1,500
Prepaid expenses and other current assets	5,994	97	74
Current portion of unsecured related party note receivable		7	6
Total current assets	232,266	2,160	4,897
Property and equipment, net	1,003
Operating lease right-of-use asset	959
Long-term investments	33,656
Other long-term assets	55
Unsecured related party note receivable		29	36
Total assets	267,939	2,189	4,933
Current liabilities:
Accounts payable	3,872	421	121
Accrued expenses	2,125	852	451
Current operating lease liability	57
Grant liability	1,500
Total current liabilities	7,554	1,273	572
Operating lease liability, less current portion	915
Grant liability		1,036	936
Derivative liability		999	539
Convertible notes, net		1,553	722
Total liabilities	8,469	4,861	2,769
Commitments and contingencies
Convertible preferred stock, value		17,051	17,051
Stockholders' equity (deficit):
Common stock, value	3
Additional paid-in capital	292,800	1,364	1,039
Accumulated other comprehensive income	7
Accumulated deficit	(33,340)	(21,087)	(15,926)
Total stockholders' equity (deficit)	259,470	(19,723)	(14,887)
Total liabilities, convertible preferred stock and stockholders' equity (deficit)	$ 267,939	$ 2,189	$ 4,933

Balance Sheets (Parenthetical)

Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019	Dec. 31, 2018
Statement Of Financial Position [Abstract]
Convertible preferred stock, par value	$ 0.0001	$ 0.0001	$ 0.0001
Convertible preferred stock, shares authorized	0	2,797,464	2,797,464
Convertible preferred stock, shares issued	0	2,617,386	2,617,386
Convertible preferred stock, shares outstanding	0	2,617,386	2,617,386
Preferred stock liquidation preference value		$ 16,288	$ 16,288
Common stock, par value	$ 0.0001	$ 0.0001	$ 0.0001
Common stock, shares authorized	900,000,000	10,088,017	10,088,017
Common stock, shares issued	31,087,395	3,641,449	3,559,484
Common stock, shares outstanding	31,087,395	3,641,449	3,559,484

Statements of Operations and Co

Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019	Dec. 31, 2018
Operating expenses:
Research and development	$ 5,830	$ 1,026	$ 8,099	$ 3,135	$ 3,793	$ 3,589
General and administrative	1,567	509	2,817	1,197	1,656	1,420
Total operating expenses	7,397	1,535	10,916	4,332	5,449	5,009
Loss from operations	(7,397)	(1,535)	(10,916)	(4,332)	(5,449)	(5,009)
Other income (expense), net	(1,059)	5	(1,337)	145	288	(88)
Net loss	(8,456)	(1,530)	(12,253)	(4,187)	$ (5,161)	$ (5,097)
Unrealized (loss)/gain on available-for-sale securities	7		7
Comprehensive loss attributable to common shareholders	$ (8,449)	$ (1,530)	$ (12,246)	$ (4,187)
Net loss per share attributable to common stockholders, basic and diluted	$ (1.12)	$ (0.43)	$ (2.38)	$ (1.18)	$ (1.45)	$ (1.47)
Weighted-average shares used in computing net loss per share attributable to common stockholders, basic and diluted	7,564,538	3,554,345	5,155,338	3,551,586	3,566,849	3,469,153
Pro forma net loss per share attributable to common stockholders, basic and diluted (unaudited)					$ (0.82)
Weighted-average shares used in computing pro forma net loss per share attributable to common stockholders, basic and diluted (unaudited)					6,186,544

Statements of Convertible Prefe

Statements of Convertible Preferred Stock and Stockholders' Deficit - USD ($) $ in Thousands	Total	Convertible Preferred Stock	Common Stock	Additional Paid-In Capital	Accumulated Deficit	Accumulated Other Comprehensive Income
Beginning balance at Dec. 31, 2017	$ (10,098)			$ 731	$ (10,829)
Temporary equity, beginning balance, shares at Dec. 31, 2017		2,607,298
Temporary equity, beginning balance at Dec. 31, 2017		$ 16,951
Beginning balance, shares at Dec. 31, 2017			3,243,291
Issuance of common stock upon exercise of stock options	112			112
Issuance of common stock upon exercise of stock options, shares			303,583
Issuance of convertible preferred stock for cash of $1.25 per share		$ 100
Issuance of convertible preferred stock for cash of $1.25 per share, shares		10,088
Issuance of restricted stock awards for advisory services, shares			12,610
Stock-based compensation	196			196
Net loss	(5,097)				(5,097)
Ending balance at Dec. 31, 2018	$ (14,887)			1,039	(15,926)
Temporary equity, ending balance, shares at Dec. 31, 2018	2,617,386	2,617,386
Temporary equity, ending balance at Dec. 31, 2018	$ 17,051	$ 17,051
Ending balance, shares at Dec. 31, 2018			3,559,484
Issuance of common stock upon exercise of stock options	13			13
Issuance of common stock upon exercise of stock options, shares			12,610
Stock-based compensation	189			189
Net loss	(4,187)				(4,187)
Ending balance at Sep. 30, 2019	(18,872)			1,241	(20,113)
Temporary equity, ending balance, shares at Sep. 30, 2019		2,617,386
Temporary equity, ending balance at Sep. 30, 2019		$ 17,051
Ending balance, shares at Sep. 30, 2019			3,572,094
Beginning balance at Dec. 31, 2018	$ (14,887)			1,039	(15,926)
Temporary equity, beginning balance, shares at Dec. 31, 2018	2,617,386	2,617,386
Temporary equity, beginning balance at Dec. 31, 2018	$ 17,051	$ 17,051
Beginning balance, shares at Dec. 31, 2018			3,559,484
Issuance of common stock upon exercise of stock options	$ 72			72
Issuance of common stock upon exercise of stock options, shares	81,965		81,965
Stock-based compensation	$ 253			253
Net loss	(5,161)				(5,161)
Ending balance at Dec. 31, 2019	$ (19,723)			1,364	(21,087)
Temporary equity, ending balance, shares at Dec. 31, 2019	2,617,386	2,617,386
Temporary equity, ending balance at Dec. 31, 2019	$ 17,051	$ 17,051
Ending balance, shares at Dec. 31, 2019			3,641,449
Beginning balance at Jun. 30, 2019	(17,417)			1,166	(18,583)
Temporary equity, beginning balance, shares at Jun. 30, 2019		2,617,386
Temporary equity, beginning balance at Jun. 30, 2019		$ 17,051
Beginning balance, shares at Jun. 30, 2019			3,565,789
Issuance of common stock upon exercise of stock options	6			6
Issuance of common stock upon exercise of stock options, shares			6,305
Stock-based compensation	69			69
Net loss	(1,530)				(1,530)
Ending balance at Sep. 30, 2019	(18,872)			1,241	(20,113)
Temporary equity, ending balance, shares at Sep. 30, 2019		2,617,386
Temporary equity, ending balance at Sep. 30, 2019		$ 17,051
Ending balance, shares at Sep. 30, 2019			3,572,094
Beginning balance at Dec. 31, 2019	$ (19,723)			1,364	(21,087)
Temporary equity, beginning balance, shares at Dec. 31, 2019	2,617,386	2,617,386
Temporary equity, beginning balance at Dec. 31, 2019	$ 17,051	$ 17,051
Beginning balance, shares at Dec. 31, 2019			3,641,449
Issuance of Series B convertible preferred stock and common stock warrants, net of issuance costs of $3.5 million	10,591			10,591
Issuance of common stock upon exercise of stock options	$ 542			542
Issuance of common stock upon exercise of stock options, shares	540,334		540,334
Proceeds from initial public offering, net of underwriters' discounts and commissions and issuance costs	$ 186,446		$ 1	186,445
Proceeds from initial public offering, net of underwriters' discounts and commissions and issuance costs, Shares			12,000,000
Conversion of convertible preferred stock	92,537		$ 2	92,535
Temporary equity, conversion of convertible preferred stock, shares		(12,503,009)
Temporary equity, conversion of convertible preferred stock		$ (92,537)
Conversion of convertible preferred stock, shares			12,503,009
Exercise of common stock warrants	1,105			1,105
Exercise of common stock warrants, shares			2,402,603
Stock-based compensation	218			218
Other comprehensive income	7					$ 7
Net loss	(12,253)				(12,253)
Ending balance at Sep. 30, 2020	$ 259,470		$ 3	292,800	(33,340)	7
Temporary equity, ending balance, shares at Sep. 30, 2020	0
Ending balance, shares at Sep. 30, 2020			31,087,395
Temporary Equity, Issuance of Series B convertible preferred stock and common stock warrants, net, shares		9,372,765
Temporary Equity, Issuance of Series B convertible preferred stock and common stock warrants, net		$ 70,971
Temporary Equity, Issuance of the Series B-1 convertible preferred stock upon conversion of convertible notes, shares		512,858
Temporary Equity, Issuance of the Series B-1 convertible preferred stock upon conversion of convertible notes		$ 4,515
Beginning balance at Jun. 30, 2020	$ (12,529)			12,355	(24,884)
Temporary equity, beginning balance, shares at Jun. 30, 2020		12,503,009
Temporary equity, beginning balance at Jun. 30, 2020		$ 92,537
Beginning balance, shares at Jun. 30, 2020			4,607,565
Issuance of common stock upon exercise of stock options	304			304
Issuance of common stock upon exercise of stock options, shares			262,285
Proceeds from initial public offering, net of underwriters' discounts and commissions and issuance costs	186,446		$ 1	186,445
Proceeds from initial public offering, net of underwriters' discounts and commissions and issuance costs, Shares			12,000,000
Conversion of convertible preferred stock	92,537		$ 2	92,535
Temporary equity, conversion of convertible preferred stock, shares		(12,503,009)
Temporary equity, conversion of convertible preferred stock		$ (92,537)
Conversion of convertible preferred stock, shares			12,503,009
Exercise of common stock warrants	1,050			1,050
Exercise of common stock warrants, shares			1,714,536
Stock-based compensation	111			111
Other comprehensive income	7					7
Net loss	(8,456)				(8,456)
Ending balance at Sep. 30, 2020	$ 259,470		$ 3	$ 292,800	$ (33,340)	$ 7
Temporary equity, ending balance, shares at Sep. 30, 2020	0
Ending balance, shares at Sep. 30, 2020			31,087,395

Statements of Convertible Pre_2

Statements of Convertible Preferred Stock and Stockholders' Deficit (Parenthetical) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2020	Dec. 31, 2018
Issuance of Series B convertible preferred stock and common stock warrants, issuance costs		$ 3.5
Initial public offering, issuance cost	$ 3.3	$ 3.3
Convertible Preferred Stock
Shares issued, price per share			$ 1.25

Statements of Cash Flows

Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended		12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019	Dec. 31, 2018
Operating activities
Net loss	$ (12,253)	$ (4,187)	$ (5,161)	$ (5,097)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation	218	189	253	196
Non-cash interest expense	76	61	88
Accretion of discounts on convertible notes	289	175	258	9
Change in fair value of derivative liability	132	84	71
Change in fair value of grant liability	464	51	100	164
Change in fair value of convertible preferred stock warrant liability	641
Gain on extinguishment of convertible notes	(199)
Amortization of available-for-sale securities	86
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	(5,919)	16	(23)	(46)
Accounts payable and accrued expenses	3,004	927	701	291
Operating lease liability	13
Net cash (used in) operating activities	(13,448)	(2,684)	(3,713)	(4,483)
Investing activities
Purchases of available-for-sale securities	(94,281)	(995)	(995)	(5,250)
Maturities of available-for-sale securities		1,745	2,495	7,250
Purchases of property and equipment	(65)
Principal payments received on related party note receivable	36	5	6	7
Net cash (used in) provided by investing activities	(94,310)	755	1,506	2,007
Financing activities
Proceeds from exercise of common stock options and common stock warrants	613	13	72	112
Proceeds from initial public offering, net of issuance costs	187,224
Proceeds from sales of convertible preferred stock and stock warrants, net of issuance costs	81,926			100
Proceeds from issuance of convertible notes, including derivative	1,666	884	884	1,266
Issuance costs of convertible notes	(2)	(5)	(10)	(14)
Proceeds from Paycheck Protection Program loan	215
Repayment of Paycheck Protection Program loan	(215)
Net cash provided by financing activities	271,427	892	946	1,464
Net increase (decrease) in cash and cash equivalents	163,669	(1,037)	(1,261)	(1,012)
Cash and cash equivalents, beginning of year	2,056	3,317	3,317	4,329
Cash and cash equivalents, end of year	165,725	2,280	$ 2,056	$ 3,317
Supplemental disclosures of cash flow information:
Purchases of property and equipment included in accounts payable and accrued liabilities	940
Deferred offering costs included in accounts payable and accrued liabilities	779
Issuance of common stock warrants in connection with Series B convertible preferred stock financing	10,591
Issuance of Series B preferred stock upon conversion of promissory notes	4,515
Recognition of warrant liability in connection with Series B convertible preferred stock financing	364
Derivative liability recorded upon issuance of convertible notes	774	$ 390
Conversion of convertible preferred stock upon closing of initial public offering	92,537
Right-of-use asset obtained in exchange for new operating lease liability	$ 975

Description of Business and Fin

Description of Business and Financial Condition	9 Months Ended	12 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Description of Business and Financial Condition	1. Description of Business Organization Athira Pharma, Inc. (the “Company”) was incorporated as M3 Biotechnology, Inc. in the state of Washington on March 31, 2011 and reincorporated in the state of Delaware on October 27, 2015. In April 2019, the Company changed its name to Athira Pharma, Inc. The Company currently has office and laboratory space in Seattle and Bothell Washington. The Company is a late clinical-stage biopharmaceutical company focused on developing small molecules to restore neuronal health and stop neurodegeneration. Reverse Stock Split On September 11, 2020, the Company effected a one-for-7.9302 reverse split of its issued and outstanding common stock, convertible preferred stock, warrants, and stock options. The par value of the common stock and convertible preferred stock was not adjusted as a result of the reverse stock split. All share and per share amounts in the accompanying unaudited condensed financial statements and notes to the unaudited condensed financial statements have been retroactively adjusted for all periods presented to reflect the reverse stock split. Initial Public Offering On September 17, 2020, the Company’s registration statement on Form S-1 (File No. 333-248428) for its initial public offering of common stock (“IPO”) was declared effective by the Securities and Exchange Commission (“SEC”). On September 22, 2020, t he Company In connection with the closing of the IPO, all of the Company’s outstanding shares of convertible preferred stock were automatically converted into 12,503,009 shares of common stock. Immediately prior to t he Company’s Liquidity and Capital Resources Since the Company’s inception, it has funded its operations primarily with proceeds from the sale and issuance of common stock, convertible preferred stock, common stock warrants, and convertible notes, and to a lesser extent from grant income and stock option exercises. From the Company’s inception through September 30, 2020, it has raised aggregate net cash proceeds of $288.5 million primarily from the issuance of its common stock, convertible preferred stock, common stock warrants, and convertible notes. As of September 30, 2020, the Company had $259.9 million in cash, cash equivalents, and investments and had not generated positive cash flows from operations. Since the Company’s inception, it has devoted substantially all of its resources to its research and development efforts such as small molecule compound discovery, nonclinical studies and clinical trials, as well as manufacturing activities, establishing and maintaining the Company’s intellectual property portfolio, hiring personnel, raising capital, and providing general and administrative support for these operations. Based upon the Company’s current operating plan, it estimates that its $259.9 million of cash, cash equivalents, and investments at September 30, 2020 will be sufficient to fund its operating expenses and capital expenditure requirements through at least the 12 months following the date of the Company’s Quarterly Report on Form 10-Q for the period ending September 30, 2020.	1. Description of Business and Financial Condition Athira Pharma, Inc. (the “Company”) was incorporated as M3 Biotechnology, Inc. in the state of Washington on March 31, 2011 and reincorporated in the state of Delaware on October 27, 2015. In April 2019, the Company changed its name to Athira Pharma, Inc. The Company currently has office and laboratory space in Seattle, Washington. The Company is a late clinical-stage biopharmaceutical company focused on developing small molecules to restore neuronal health and stop neurodegradation. Risks and Uncertainties The Company is subject to a number of inherent risks which include, but are not limited to, the need to obtain adequate additional funding, possible failure of clinical trials or other events demonstrating a lack of clinical safety or efficacy of its product candidates, dependence on key personnel, reliance on third-party service providers for manufacturing or drug product and conduct of clinical trials, the ability to successfully secure its proprietary technology, and risks related to the regulatory approval and commercialization of a product candidate. Additionally, the development and commercialization of new drug products is highly competitive. There are a number of large pharmaceutical and biotechnology companies developing products for the treatment of neurodegenerative diseases that may have significantly greater financial resources and expertise in drug product development. Products or technologies developed by competitors may diminish or render obsolete the Company’s existing products under development. Liquidity and Capital Resources The accompanying financial statements have been prepared assuming that the Company will continue as a going concern. The Company has incurred net operating losses since its inception and had an accumulated deficit of $21.1 million as of December 31, 2019. The Company had cash and cash equivalents of $2.1 million Management expects operating losses to continue for the foreseeable future. There can be no assurance that the Company will ever earn revenues or achieve profitability, or if achieved, that they will be sustained on a continuing basis. In addition, the manufacturing, clinical and preclinical development activities as well as the commercialization of the Company’s therapies, if approved, will require significant additional financing. The Company may be unable to secure such financing when needed, or if available, such financings may be under terms that are unfavorable to the Company or the current stockholders. If the Company is unable to raise additional funds when needed, it may be required to delay, reduce the scope of, or eliminate development programs, which may adversely affect its business and operations.

Significant Accounting Policies

Significant Accounting Policies	9 Months Ended	12 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
Accounting Policies [Abstract]
Significant Accounting Policies	2. Significant Accounting Policies Basis of Presentation The condensed consolidated financial statements have been prepared in conformity with U.S. generally accepted accounting principles (“U.S. GAAP”). During the third quarter of 2020, the Company incorporated Athira Pharma Australia PTY LTD in Australia and as of September 30, 2020, operations have yet to commence. Unaudited Interim Condensed Financial Statements The accompanying unaudited condensed balance sheet as of September 30, 2020, and condensed statements of operations and comprehensive loss, condensed statements of cash flows, and condensed statements of convertible preferred stock and stockholders’ deficit for the three and nine months ended September 30, 2020 and 2019, are unaudited. The balance sheet as of December 31, 2019 was derived from the audited financial statements as of and for the year ended December 31, 2019. The unaudited interim condensed financial statements have been prepared on a basis consistent with the audited annual financial statements as of and for the year ended December 31, 2019, and, in the opinion of management, reflect all adjustments, consisting solely of normal recurring adjustments, necessary for the fair presentation of the Company’s financial position as of September 30, 2020, and the condensed results of its operations and its cash flows for the three and nine months ended September 30, 2020 and 2019. The financial data and other information disclosed in these notes related to the three and nine months ended September 30, 2020 and 2019 are also unaudited. The condensed results of operations for the three and nine months ended September 30, 2020 are not necessarily indicative of the results to be expected for the full year ending December 31, 2020 or any other period. These interim condensed financial statements should be read in conjunction with the Company’s audited financial statements included elsewhere in this prospectus. Fair Value Measurements The carrying amounts of certain financial instruments, including cash and cash equivalents, accounts payable and accrued expenses approximate their fair values due to the short-term nature of those amounts. The fair values of the grant liability to Life Sciences Discovery Fund (“LSDF”), the derivative liability, and the convertible preferred stock warrant liability were estimated using Level 3 unobservable inputs. Convertible Preferred Stock Warrant Liability Freestanding warrants to purchase shares of the Company’s convertible preferred stock are accounted for as liabilities at fair value, because the shares underlying the warrants contain contingent redemption features outside the control of the Company. Warrants classified as liabilities are recorded on the Company’s balance sheets at their fair value on the date of issuance and remeasured to fair value on each subsequent reporting period, with the changes in fair value recognized as a component of other income (expense), net in the accompanying statements of operations. The Company will continue to adjust the liability for changes in the fair value of these warrants until the earlier of the exercise of the warrants, the expiration of the warrants, or until such time as the warrants are no longer considered liability instruments. Short-term and Long-term Investments The Company generally invests its excess cash in investment grade short- to intermediate-term fixed income securities. Such investments are included in cash and cash equivalents, short-term investments, and long-term investments on the consolidated balance sheets, classified as available-for-sale, and reported at fair value with unrealized gains and losses included in accumulated other comprehensive loss. Realized gains and losses on the sale of these securities are recognized in net loss. The Company periodically evaluates whether declines in fair values of its investments below their book value are other-than-temporary. This evaluation consists of several qualitative and quantitative factors regarding the severity and duration of the unrealized loss as well as the Company’s ability and intent to hold the investment until a forecasted recovery occurs. Additionally, the Company assesses whether it has plans to sell the security or it is more likely than not it will be required to sell any investment before recovery of its amortized cost basis. Factors considered include quoted market prices, recent financial results and operating trends, implied values from any recent transactions or offers of investee securities, credit quality of debt instrument issuers, other publicly available information that may affect the value of the investments, duration and severity of the decline in value, and our strategy and intentions for holding the investment. Use of Estimates The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of expenses during the reporting period. Estimates include those used for fair value of assets and liabilities, accrued liabilities, valuation allowance for deferred tax assets, and stock-based compensation. Management evaluates related assumptions on an ongoing basis using historical experience and other factors, and adjusts those estimates and assumptions when facts and circumstances dictate. Research and Development Expenses Research and development expenses consist primarily of direct and indirect costs incurred for research activities, including development of our pipeline from the Company’s proprietary drug discovery platform (“ATH platform”). The Company’s drug discovery efforts and the development of its product candidates. Direct costs include laboratory materials and supplies, contracted research and manufacturing, clinical trial costs, consulting fees, and other expenses incurred to sustain the Company’s research and development program. Indirect costs include personnel-related expenses, consisting of employee salaries, related benefits, and stock-based compensation expense for employees engaged in research and development activities, and facilities and other expenses consisting of direct and allocated expenses for rent and depreciation and lab consumables. Research and development costs are expensed as incurred. In-licensing fees and other costs to acquire technologies used in research and development that have not yet received regulatory approval and that are not expected to have an alternative future use are expense when incurred. Non-refundable advance payments for goods and services that will be used over time for research and development are capitalized and recognized as goods are delivered or as the related services are performed. The Company estimates the period over which such services will be performed and the level of effort to be expended in each period. If actual timing of performance or the level of effort varies from the estimate, the Company adjusts the amounts recorded accordingly. The Company has not experienced any material differences between accrued or prepaid costs and actual costs since inception. Leases As discussed in Recently Adopted Accounting Standards Topic 842 - Leases The Company’s lease contains an option to extend the lease; lease terms are adjusted for these options only when it is reasonably certain the Company will exercise these options. The Company’s lease agreement does not contain residual value guarantees or covenants. The Company has made a policy election regarding its real estate leases not to separate nonlease components from lease components, to the extent they are fixed. Nonlease components that are not fixed are expensed as incurred as variable lease expense. The Company’s lease includes variable nonlease components, such as common-area maintenance costs. The Company has elected not to record on the balance sheet a lease that has a lease term of 12 months or less and does not contain a purchase option that the Company is reasonably certain to exercise. The Company accounts for leases with initial terms of 12 months or less as operating expenses on a straight-line basis over the lease term. Lease expense is recognized within operating expenses on a straight-line basis over the terms of the lease. Incentives granted under the Company’s facilities lease, including rent holidays, are recognized as adjustments to lease expense on a straight-line basis over the term of the lease. Stock-based Compensation The Company measures compensation expense for all stock-based payments to employees, officers and directors based on the estimated fair value of the award at the grant date. For stock options, the Company estimates the grant date fair value of each option award using the Black-Scholes option-pricing model. Compensation expense is recognized over the requisite service period on a straight-line basis. Forfeitures are recognized as they occur. The Company records compensation expense for stock option grants subject to performance-based milestone vesting using the accelerated attribution method over the remaining service period when management determines that achievement of the milestone is probable. Management evaluates when the achievement of a performance-based milestone is probable based on the relative satisfaction of the performance conditions as of the reporting date. The Company adopted Accounting Standards Update (“ASU”) 2018-07 as of January 1, 2020. As a result, stock-based payments issued to non-employees prior to January 1, 2020 have been recorded at their fair values as of the transition date and are no longer subject to periodic adjustments as the underlying equity instruments vest. Any remaining compensation expense is recognized over the remaining vesting term on a straight-line basis, which reflects the service period, based on the fair value as of January 1, 2020. Net Loss Per Share Attributable to Common Stockholders Basic net loss per share attributable to common stockholders is calculated by dividing the net loss attributable to common stockholders by the weighted-average number of shares of common stock outstanding for the period, without consideration of potentially dilutive securities. Diluted net loss per share attributable to common stockholders is the same as basic net loss per share attributable to common stockholders since the effect of potentially dilutive securities is anti-dilutive given the net loss of the Company. Segments The Company has determined that it operates and manages one operating segment, which is the business of developing and commercializing therapeutics. The Company’s chief operating decision maker, its chief executive officer, reviews financial information on an aggregate basis for the purpose of allocating resources. Emerging Growth Company Status The Company is an emerging growth company, as defined in the Jumpstart Our Business Startups Act of 2012 (“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 is (a) no longer an emerging growth company or (b) affirmatively and irrevocably opt out of the extended transition period provided in the JOBS Act. As a result, these financial statements may not be comparable to companies that comply with the new or revised accounting pronouncements as of public company effective dates. Recently Adopted Accounting Pronouncements In February 2016, the Financial Accounting Standards Board (“FASB”) issued ASU 2016-02, Leases (Topic 842) Leases (Topic 842) Targeted Improvements In adopting the new standard, the Company utilized certain practical expedients available. These practical expedients include waiving reassessment of 1) whether any expired or existing contracts are or contain leases; 2) lease classification of expired or existing leases; and 3) initial direct costs for existing leases. The Company also elected to use hindsight in determining the lease term and in assessing impairment of its ROU assets. Furthermore, the Company has made a policy decision regarding its real estate leases not to separate nonlease components from lease components, to the extent they are fixed. The Company has also elected not to record on the balance sheet a lease that has a lease term of 12 months or less and does not contain a purchase option that the Company is reasonably certain to exercise. The standard had a material impact on the Company’s unaudited condensed balance sheets but did not have a material impact on its unaudited condensed statements of operations or unaudited condensed statements of cash flows. The most significant impact was the recognition of $1.0 million and $1.0 million of operating lease ROU assets and liabilities, respectively. Refer to Note 8, Leases, for additional information regarding leases. In June 2018, the FASB issued ASU 2018-07, Compensation – Stock Compensation (Topic 326) Improvements to Nonemployee Share-Based Payment Accounting In August 2018, the FASB issued ASU 2018-13, Disclosure Framework – Changes to the Disclosure Requirements for Fair Value Measurement Recent Accounting Pronouncements Not Yet Adopted In June 2016, the FASB issued ASU 2016-13, Financial Instruments: Credit Losses (Topic 326) Although there were several other new accounting pronouncements issued or proposed by the FASB, we do not believe any of these have had or will have material impact on our condensed consolidated financial statements.	2. Significant Accounting Policies Basis of Presentation The financial statements have been prepared in conformity with U.S. generally accepted accounting principles (“U.S. GAAP”). Use of Estimates The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of expenses during the reporting period. Estimates include those used for fair value of assets and liabilities, accrued liabilities, valuation allowance for deferred tax assets, and stock-based compensation. Management evaluates related assumptions on an ongoing basis using historical experience and other factors, and adjusts those estimates and assumptions when facts and circumstances dictate. Cash and Cash Equivalents The Company considers highly liquid investments with original maturities of three months or less to be cash equivalents. Short-term Investments Short-term investments consist entirely of fixed income certificates of deposit with original maturities of greater than 90 days but not more than one year. These securities are classified as available-for-sale and reported at estimated fair value with unrealized gains and losses, if any, included in accumulated other comprehensive loss in stockholders’ deficit. The cost of investments for purposes of computing realized and unrealized gains and losses is based on the specific identification method. If the estimated fair value of a security is below its carrying value, the Company evaluates whether it is more likely than not that it will sell the security before its anticipated recover in market value and whether evidence indicating that the cost of the investment is recoverable within a reasonable period of time outweighs the evidence to the contrary. Realized gains, realized losses and declines in the value of investments judged to be other than temporary, are included in other income (expense), net. Concentration of Credit Risk The Company is exposed to credit risk from its deposits of cash in excess of amounts insured by the Federal Deposit Insurance Corporation. The Company has not experienced any losses on its deposits of cash since inception. Fair Value Measurements The carrying amounts of certain financial instruments, including cash and cash equivalents, short-term investments, and accounts payable and accrued expenses approximate their fair values due to the short-term nature of those amounts. The fair values of the grant liability to Life Services Discovery Fund (“LSDF”) and the derivative liability were estimated using Level 3 unobservable inputs. Grant Liability The grant liability associated with the grants from the Washington LSDF is accounted for under Accounting Standards Codification (“ASC”) 825-10, Financial Instruments − Overall Derivative Liability, Convertible Notes Discount and Amortization The Company’s convertible notes (see Note 8) have conversion and redemption features that meet the definition of an embedded derivative and are therefore subject to derivative accounting. The initial fair value of the derivative is recorded as a discount to the convertible notes, with a corresponding derivative liability. The discount to the convertible notes is amortized using the effective interest method. The amortization of the discount is included in other income (expense), net in the statements of operations and comprehensive loss. The derivative liability related to these features is recorded at estimated fair value on a recurring basis. Any changes in fair value are reflected in other income (expense), net in the statements of operations and comprehensive loss at each period end while such instruments are outstanding. The derivative liability was settled in May 2020 upon conversion of the underlying convertible notes into Series B-1 convertible preferred stock. See Note 17. Grant Income In January 2019, the Alzheimer’s Association awarded the Company a $1.0 million Part the Cloud Research and Development Expenses Research and development expenses consist primarily of direct and indirect costs incurred for research activities, including development of the ATH platform, the Company’s drug discovery efforts and the development of its product candidates. Direct costs include laboratory materials and supplies, contracted research and manufacturing, clinical trial costs, consulting fees, and other expenses incurred to sustain the Company’s research and development program. Indirect costs include personnel-related expenses, consisting of employee salaries, related benefits, and stock-based compensation expense for employees engaged in research and development activities, and facilities and other expenses consisting of direct and allocated expenses for rent and depreciation and lab consumables. Research and development costs are expensed as incurred. In-licensing fees and other costs to acquire technologies used in research and development that have not yet received regulatory approval and that are not expected to have an alternative future use are expense when incurred. Non-refundable advance payments for goods and services that will be used over time for research and development are capitalized and recognized as goods are delivered or as the related services are performed. The Company estimates the period over which such services will be performed and the level of effort to be expended in each period. If actual timing of performance or the level of effort varies from the estimate, the Company will adjust the amounts recorded accordingly. The Company has not experienced any material differences between accrued or prepaid costs and actual costs since inception. General and Administrative Expenses General and administrative expenses consist primarily of personnel-related costs, consisting of employee salaries, related benefits, and stock-based compensation expense for employees in the executive, legal, finance and accounting, human resources, and other administrative functions. General and administrative expenses also include third-party costs such as legal costs, insurance costs, accounting, auditing and tax related fees, consulting fees and facilities and other expenses not otherwise included as research and development expenses. General and administrative costs are expensed as incurred. Stock-based Compensation The Company measures compensation expense for all stock-based payments to employees, officers and directors based on the estimated fair value of the award at the grant date. For stock options, the Company estimates the grant date fair value of each option award using the Black-Scholes option-pricing model. Compensation expense is recognized over the requisite service period on a straight-line basis. Forfeitures are recognized as they occur. The Company records compensation expense for stock option grants subject to performance-based milestone vesting using the accelerated attribution method over the remaining service period when management determines that achievement of the milestone is probable. Management evaluates when the achievement of a performance-based milestone is probable based on the relative satisfaction of the performance conditions as of the reporting date. Stock-based payments issued to non-employees are recorded at their fair values, subject to periodic adjustments as the underlying equity instruments vest. Compensation expense is recognized over the vesting term on a straight-line basis, which reflects the service period. Options granted to non-employee service providers are valued at estimated fair value using the Black-Scholes option-pricing model and are remeasured over the vesting term as earned. Awards of restricted stock to non-employees are adjusted through stock-based compensation expense at each reporting period end until the shares vest to reflect the current fair value of such awards. Income Taxes Income taxes are accounted for under the asset and liability method. Deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases and operating loss and tax credit carry forwards. Deferred tax assets and liabilities 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. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income in the period that includes the enactment date. In assessing the Company’s ability to realize deferred tax assets, management considers whether it is more likely than not that some portion or all of the deferred tax assets will not be realized. The ultimate realization of deferred tax assets is dependent upon the generation of future taxable income during the periods in which those temporary differences are deductible. Management considers the scheduled reversal of deferred tax liabilities, projected future income, tax planning strategies in making this assessment. The Company recognizes the effect of income tax positions only if those positions are more likely than not of being sustained. Recognized income tax positions are measured at the largest amount that is greater than 50% likely of being realized. Changes in recognition or measurement are reflected in the period in which the change in judgment occurs. The Company accrues interest and penalties related to unrecognized tax benefits in its provision for incomes taxes. Comprehensive Loss Comprehensive loss consists of net loss and other gains and losses affecting stockholders’ deficit that, under U.S. GAAP, are excluded from net loss. The Company has no items of other comprehensive loss. As such, net loss equals comprehensive loss. Net Loss Per Share Attributable to Common Stockholders Basic net loss per share attributable to common stockholders is calculated by dividing the net loss attributable to common stockholders by the weighted-average number of shares of common stock outstanding for the period, without consideration of potentially dilutive securities. Diluted net loss per share attributable to common stockholders is the same as basic net loss per share attributable to common stockholders since the effect of potentially dilutive securities is anti-dilutive given the net loss of the Company. Unaudited Pro Forma Net Loss Per Share Attributable to Common Stockholders The unaudited pro forma basic and diluted net loss per share attributable to common stockholders has been computed to give effect to the conversion of all shares of convertible preferred stock into common stock, the net exercise of outstanding warrants for shares of common stock, and the repayment of the grant liability upon the closing of a firm-commitment underwritten public offering (“IPO”) resulting in at least $50.0 million in gross proceeds. The unaudited pro forma net loss per share attributable to common stockholders does not include the shares to be sold from the proposed IPO. Segments The Company has determined that it operates and manages one operating segment, which is the business of developing and commercializing therapeutics. The Company’s chief operating decision maker, its chief executive officer, reviews financial information on an aggregate basis for the purpose of allocating resources. Related Party Transactions As of December 31, 2018 and 2019, the Company had an unsecured note receivable outstanding from its chief executive officer of approximately $42,000 and $36,000, respectively. The note bears interest at 1.45% and requires monthly payments with final repayment in April 2025. The note is included in current portion of unsecured related party note receivable and unsecured related party note receivable in the accompanying balance sheets. Interest income is recognized using the effective interest method, and is included in other income (expense), net in the statements of operations and comprehensive loss. Emerging Growth Company Status The Company is an emerging growth company, as defined in the Jumpstart Our Business Startups Act of 2012 (“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 is (a) no longer an emerging growth company or (b) affirmatively and irrevocably opt out of the extended transition period provided in the JOBS Act. As a result, these financial statements may not be comparable to companies that comply with the new or revised accounting pronouncements as of public company effective dates. Recent Accounting Pronouncements Not Yet Adopted In February 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2016-02, Leases In June 2016, the FASB issued ASU 2016-13, Financial Instruments: Credit Losses (Topic 326) In August 2018, the FASB issued ASU 2018-15, Intangible − Goodwill and Others − Internal-Use Software (Subtopic 350-40) Customer's Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract Disclosure Framework – Changes to the Disclosure Requirements for Fair Value Measurement In June 2018, the FASB issued ASU 2018-07, Compensation – Stock Compensation (Topic 326) Improvements to Nonemployee Share-Based Payment Accounting

Short-Term Investments

Short-Term Investments	12 Months Ended
	Dec. 31, 2019
Investments Debt And Equity Securities [Abstract]
Short-term Investments	3. Short-term Investments Short-term investments consisted of available-for-sale securities as follows (in thousands): Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value December 31, 2018 Certificates of deposit $ 1,500 $ — $ — $ 1,500 December 31, 2019 Certificates of deposit $ — $ — $ — $ — All short-term investments had contractual maturities of less than one year.

Fair Value

Fair Value	9 Months Ended	12 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
Fair Value Disclosures [Abstract]
Fair Value	3 . Fair Value The Company has certain assets and liabilities that are measured at fair value on a recurring basis according to a fair value hierarchy that prioritizes the inputs, assumptions and valuation techniques used to measure fair value. The three levels of the fair value hierarchy are: Level 1 —Unadjusted quoted prices in active markets that are accessible at the measurement date for identical, unrestricted assets or liabilities. Level 2 —Quoted prices in markets that are not active or financial instruments for which all significant inputs are observable, either directly or indirectly. Level 3 —Inputs are generally unobservable and reflect management’s estimates of assumptions that market participants would use in pricing the asset or liability. The fair values are determined using model-based techniques, including probability-based simulation methodologies. The determination of a financial instrument’s level within the fair value hierarchy is based on an assessment of the lowest level of any input that is significant to the fair value measurement. The Company considers observable data to be market data, which is readily available, regularly distributed or updated, reliable and verifiable, not proprietary, and provided by independent sources that are actively involved in the relevant market. The following table reflects the Company’s financial asset balances measured on a recurring basis as of September 30, 2020 (in thousands): Level Amortized Cost Unrealized Gains Unrealized Losses Fair Value Cash equivalents: Money market fund 1 $ 66,596 — — $ 66,596 Commercial paper 2 70,392 — (3 ) 70,389 U.S. government debt and agency securities 2 835 — — 835 U.S. treasury bills 2 14,999 — — 14,999 Total cash equivalents $ 152,822 $ — $ (3 ) $ 152,819 Short-term investments: Commercial paper 2 30,393 2 (1 ) 30,394 U.S. government debt and agency securities 2 29,220 7 — 29,227 Corporate bonds 2 926 — — 926 Total short-term investments $ 60,539 $ 9 $ (1 ) $ 60,547 Long-term investments: U.S. government debt and agency securities 2 32,634 11 (9 ) 32,636 U. S. treasury bills 2 1,020 — — 1,020 Total long-term investments $ 33,654 $ 11 $ (9 ) $ 33,656 The Company evaluated its investments for other-than-temporary impairment and considers the decline in market value for the securities to be primarily attributable to current economic and market conditions. For the investments, it is not more-likely-than-not that the Company will be required to sell the investments, and the Company does not intend to do so prior to the recovery of the amortized cost basis. Prior to the IPO, the Company’s level 3 financial liabilities carried at fair value and remeasured on a recurring basis are the grant liability, derivative liability, and the convertible preferred stock warrant liability. In the third quarter the Company recorded an additional $464,000 to bring the total grant liability to $1.5 million as the Company’s IPO triggered the repayment obligation (see Note 6), and the derivative was settled upon the Company’s conversion of its convertible notes in May 2020 (see Note 7). The losses resulting from the change in fair value of the grant liability, the bifurcated conversion and redemption features related to the derivative liability, and the convertible preferred stock warrant liability are classified as other income (expense), net in the accompanying condensed consolidated statements of operations and comprehensive loss. Changes in any of the assumptions related to the unobservable inputs identified may change the fair value of these instruments. For example, an increase in interest rates would generally correspond to a decrease in the fair value of the liabilities. The following table presents the activity for the grant liability for the year ended December 31, 2019 and nine months ended September 30, 2020 (in thousands): Year Ended December 31, 2019 Nine Months Ended September 30, 2020 Fair value at beginning of period $ 936 $ 1,036 Change in fair value of grant liability 100 464 Fair value at end of period $ 1,036 $ 1,500 The following table presents the activity for the derivative liability for the year ended December 31, 2019 and nine months ended September 30, 2020 (in thousands): Year Ended December 31, 2019 Nine Months Ended September 30, 2020 Fair value at beginning of period $ 539 $ 999 Derivative liability recorded upon issuance of convertible notes 389 774 Change in fair value of derivative liability 71 132 Derivative liability settled upon conversion of convertible notes — (1,905 ) Fair value at end of period $ 999 $ — The following table presents the activity for the convertible preferred stock warrant liability Nine Months Ended September 30, 2020 Fair value at beginning of period $ — Recognition of convertible preferred stock warrant liability 364 Change in fair value 641 Settlement upon IPO (1,005 ) Fair value at end of period $ —	4. Fair Value The Company has certain assets and liabilities that are measured at fair value on a recurring basis according to a fair value hierarchy that prioritizes the inputs, assumptions and valuation techniques used to measure fair value. The three levels of the fair value hierarchy are: Level 1 —Unadjusted quoted prices in active markets that are accessible at the measurement date for identical, unrestricted assets or liabilities. Level 2 —Quoted prices in markets that are not active or financial instruments for which all significant inputs are observable, either directly or indirectly. Level 3 —Inputs are generally unobservable and reflect management’s estimates of assumptions that market participants would use in pricing the asset or liability. The fair values are determined using model-based techniques, including probability-based simulation methodologies. The determination of a financial instrument’s level within the fair value hierarchy is based on an assessment of the lowest level of any input that is significant to the fair value measurement. The Company considers observable data to be market data which is readily available, regularly distributed or updated, reliable and verifiable, not proprietary, and provided by independent sources that are actively involved in the relevant market. The fair value hierarchy of the Company’s assets and liabilities carried at fair value and measured on a recurring basis was as follows (in thousands): As of December 31, 2018 Level 1 Level 2 Level 3 Total Assets: Short-term investments – Certificates of Deposit $ — $ 1,500 $ — $ 1,500 Total $ — $ 1,500 $ — $ 1,500 Liabilities: Grant liability — — 936 936 Derivative liability (see Note 8) — — 539 539 Total $ — $ 1,500 $ 1,475 $ 2,975 As of December 31, 2019 Level 1 Level 2 Level 3 Total Liabilities: Grant liability $ — $ — $ 1,036 $ 1,036 Derivative liability (see Note 8) — — 999 999 Total $ — $ — $ 2,035 $ 2,035 The following table presents the activity for grant liability for the years ended December 31, 2018 and 2019 (in thousands): Year Ended December 31, 2018 2019 Fair value at beginning of period $ 772 $ 936 Change in fair value of grant liability 164 100 Fair value at end of period $ 936 $ 1,036 The following table presents the activity for derivative liability for the years ended December 31, 2018 and 2019 (in thousands): Year Ended December 31, 2018 2019 Fair value at beginning of period $ — $ 539 Derivative liability recorded upon issuance of convertible notes 539 389 Change in fair value of derivative liability — 71 Fair value at end of period $ 539 $ 999 The losses resulting from the change in fair value of the grant liability and the bifurcated conversion and redemption features related to the derivative liability are classified as other income (expense), net in the accompanying statements of operations and comprehensive loss. Changes in any of the assumptions related to the unobservable inputs identified may change the fair value of these instruments. For example, an increase in interest rates would generally correspond to a decrease in the fair value of the liabilities.

Accrued Expenses

Accrued Expenses	9 Months Ended	12 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
Payables And Accruals [Abstract]
Accrued Expenses	4 . Accrued Expenses Accrued expenses consisted of the following (in thousands): As of December 31, 2019 As of September 30, 2020 Research and development expenses $ 536 $ 1,672 Employee compensation and benefits 230 229 Professional services and other 86 224 Total accrued expenses $ 852 $ 2,125	5. Accrued Expenses Accrued expenses consisted of the following (in thousands): As of December 31, 2018 2019 Research and development expenses $ 299 $ 536 Employee compensation and benefits 72 230 Professional services and other 80 86 Total accrued expenses $ 451 $ 852

Other Income (Expense), Net

Other Income (Expense), Net	9 Months Ended	12 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
Other Income And Expenses [Abstract]
Other Income (Expense), Net	5 . Other Income (Expense), Net Other income (expense), net consisted of the following (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2019 2020 2019 2020 Part the Cloud research grant $ 189 $ — $ 472 $ 22 Interest and other income 12 35 44 45 Interest expense (98 ) — (236 ) (366 ) Change in fair value of derivative liability (77 ) — (84 ) (132 ) Change in fair value of grant liability (21 ) (453 ) (51 ) (464 ) Change in convertible preferred stock warrant liability — (641 ) — (641 ) Gain on extinguishment of convertible notes — — — 199 Total other income (expense), net $ 5 $ (1,059 ) $ 145 $ (1,337 )	6. Other Income (Expense), Net Other income (expense), net consisted of the following (in thousands): Year Ended December 31, 2018 2019 Part the Cloud research grant $ — $ 754 Interest and other income 85 51 Interest expense (9 ) (346 ) Change in fair value of derivative liability — (71 ) Change in fair value of grant liability (164 ) (100 ) Total other income (expense), net $ (88 ) $ 288

Significant Agreements

Significant Agreements	9 Months Ended	12 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Significant Agreements	6. Significant Agreements Washington State University (“WSU”) License Agreement In December 2011, the Company entered into an exclusive license agreement with sublicensing terms with Washington State University Research Fund (“WSURF”), which, after the dissolution of WSURF in 2013, was superseded by an amended and restated exclusive license agreement with sublicensing terms between the Company and Washington State University (“WSU”) in 2015. Under this agreement, the Company has an exclusive license to make, use, sell, and offer for sale a chemical compound that forms the underlying technology of the drug therapies being developed by the Company. To keep in good standing, the agreement requires the Company to meet certain development milestones and pay an annual maintenance fee. All contractual requirements have been met as of September 30, 2020. As of September 30, 2020, the Phase 2 clinical trial milestone had been reached and a $50,000 liability to WSU was recorded. The Company may also be obligated to pay the following if the related milestones are reached: • $300,000 – At initiation of the first Phase 3 clinical trial in the United States, European Union or Japan for the first licensed product. • $600,000 – Marketing approval in the United States, European Union or Japan for the first licensed product. Under the terms of the agreement, the Company will pay a royalty in the mid-single digits of net sales, with the first $100,000 of net sales being exempt from royalty payment, and annual minimum royalty payments of $25,000 beginning after the first commercial sale of a licensed product. As of September 30, 2020, the Company had not incurred a royalty obligation under this agreement. Additionally, the agreement allows the Company to sublicense the rights conveyed by the agreement, subject to additional payments to WSU for sublicense consideration received. Such amounts are dependent on the terms of the underlying sublicense and range from the mid-single digits to mid-teens of any non-sales based payments received, and low twenties of net sales based sublicense royalties. As of September 30, 2020, the Company has not entered into or incurred any liability from a sublicense agreement. Grant Liability In 2014 and 2015, the Company received $250,000 and $500,000, respectively, from LSDF under the terms of two matching grant award agreements. In connection with the agreements, LSDF retained the right to receive cash payments of 2.0 times the amounts received, or $1.5 million, upon the occurrence of specified triggering events, including: • receipt of license revenue, sales revenue, or consideration related to the underlying IP; • transfers the underlying IP without receiving consideration; • relocation of the Company from Washington state; • completion of an initial public offering; • a third-party acquisition of a controlling interest in the Company, and; • termination of the agreements. To appropriately capture the economics of this arrangement, the grant liability is accounted for under ASC 825-10, Financial Instruments −Overall The estimated fair value of the grant liability was $1.0 million as of December 31, 2019. The consummation of the Company’s IPO in September 2020 was a triggering event under the terms of the grant and the liability was remeasured to the pay-off amount of $1.5 million as of September 30, 2020. The changes in the fair value of the liability resulted in expense of approximately $453,000 and $21,000 for the three months ended September 30, 2020 and 2019, respectively, and $464,000 and $51,000 for the nine months ended September 30, 2020 and 2019, respectively, which were included in other income (expense), net in the accompanying condensed consolidated statements of operations and comprehensive loss.	7. Significant Agreements Washington State University (“WSU”) License Agreement In December 2011, the Company entered into an exclusive license agreement with sublicensing terms with Washington State University Research Fund (“WSURF”), which, after the dissolution of WSURF in 2013, was superseded by an amended and restated exclusive license agreement with sublicensing terms between the Company and WSU in 2015. Under this agreement, the Company has an exclusive license to make, use, sell, and offer for sale a chemical compound that forms the underlying technology of the drug therapies being developed by the Company. To keep in good standing, the agreement requires the Company to meet certain development milestones and pay an annual maintenance fee. All contractual requirements have been met as of December 31, 2019. The Company may also be obligated to pay the following if the related milestones are reached: • $50,000 – At initiation of the first Phase 2 clinical trial in the United States, European Union or Japan for the first licensed product. • $300,000 – At initiation of the first Phase 3 clinical trial in the United States, European Union or Japan for the first licensed product. • $600,000 – Marketing approval in the United States, European Union or Japan for the first licensed product. As of December 31, 2019, none of these milestones had been reached. Under the terms of the agreement, the Company will pay a royalty in the mid-single digits of net sales, with the first $100,000 of net sales being exempt from royalty payment, and annual minimum royalty payments of $25,000 beginning after the first commercial sale of a licensed product. As of December 31, 2019, the Company had not incurred a royalty obligation under this agreement. Additionally, the agreement allows the Company to sublicense the rights conveyed by the agreement, subject to additional payments to WSU for sublicense consideration received. Such amounts are dependent on the terms of the underlying sublicense, and range from the mid-single digits to mid-tens of any non-sales based payments received, and low twenties of net sales based sublicense royalties. As of December 31, 2019, the Company had not entered into or incurred any liability from a sublicense agreement. Grant Liability In 2014 and 2015, the Company received $250,000 and $500,000, respectively, from the Washington LSDF under the terms of two matching grant award agreements. In connection with the agreements, LSDF retained the right to receive cash payments of up to 2.0 times the amounts received, or $1.5 million, upon the occurrence of specified triggering events, including: • receipt of license revenue, sales revenue, or consideration related to the underlying IP; • transfers the underlying IP without receiving consideration; • relocation of the Company from Washington state; • completion of an initial public offering; • a third-party acquisition of a controlling interest in the Company, and; • termination of the agreements. As of December 31, 2019, no triggering events have occurred and no payments to LSDF have been made. To appropriately capture the economics of this arrangement, the grant liability is accounted for under ASC 825-10, Financial Instruments −Overall The estimated fair value of the grant liability was $936,000 and $1.0 million as of December 31, 2018 and 2019, respectively. The changes in the fair value of the liability resulted in losses of $164,000 and $100,000 for the years ended December 31, 2018 and 2019, respectively, which were included in other income (expense), net in the accompanying statements of operations and comprehensive loss.

Convertible Notes

Convertible Notes	12 Months Ended
	Dec. 31, 2019
Debt Disclosure [Abstract]
Convertible Notes	8. Convertible Notes The Company issued unsecured convertible notes with aggregate principal amounts of $1.3 million and $884,000 in 2018 and 2019, respectively. The notes accrue interest at a rate of 5% per year and mature in December 2021, unless earlier converted. No principal or interest is payable prior to maturity as the convertible notes and any accrued interest will automatically convert upon a qualified financing event at a conversion price equal to 85% of the price per share of the qualified financing. Holders may also elect to convert their notes to shares of common stock upon the maturity of the notes at the then fair value of common stock. If the Company experiences a change in control, holders may either convert the outstanding principal amount plus any accrued interest into shares of common stock at the then fair value of common stock or may require the Company to repurchase the notes in cash at a price equal to 200% of the outstanding principal amount plus any accrued interest. Certain conversion and redemption features as described above were determined to be an embedded derivative requiring bifurcation and separate accounting in accordance with ASC 815, Derivatives and Hedging In May 2020, the outstanding principal balance of the convertible notes of $2.2 million and accrued interest of $131,000 converted into 294,197 shares of Series B-1 convertible preferred stock. See Note 17. The carrying value of the convertible notes as of December 31 were as follows (in thousands): As of December 31, 2018 2019 Convertible note principal and accrued interest $ 1,268 $ 2,241 Less: unamortized discount for issuance costs (14 ) (18 ) Less: unamortized discount related to derivative liability (532 ) (670 ) Net carrying value, convertible notes $ 722 $ 1,553

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2019
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	9. Commitments and Contingencies Operating Leases The Company leases office and laboratory space with a one-year lease term. Rent is expensed as incurred. The Company incurred rent expense of approximately $82,000 and $97,000 for the years ended December 31, 2018 and 2019, respectively. The Company will continue to account for its leases under ASC 840, Leases, Leases Recent Accounting Pronouncements Not Yet Adopted Legal Proceedings From time to time, the Company may have certain contingent liabilities that arise in the ordinary course of its business activities. The Company accrues a liability for such matters when it is probable that future expenditures will be made and that such expenditures can be reasonably estimated. Significant judgment is required to determine both probability and the estimated amount. Indemnifications In the ordinary course of business, the Company enters into agreements that may include indemnification provisions. Pursuant to such agreements, the Company may indemnify, hold harmless and defend an indemnified party for losses suffered or incurred by the indemnified party. Some of the provisions will limit losses to those arising from third party actions. In some cases, the indemnification will continue after the termination of the agreement. The maximum potential amount of future payments the Company could be required to make under these provisions is not determinable. The Company has never incurred material costs to defend lawsuits or settle claims related to these indemnification provisions. The Company intends to enter into indemnification agreements with its directors and officers that may require the Company to indemnify its directors and officers against liabilities that may arise by reason of their status or service as directors or officers to the fullest extent permitted by Delaware corporate law. The Company currently has directors’ and officers’ insurance coverage that reduces its exposure and enables the Company to recover a portion of any future amounts paid. The Company believes the estimated fair value of these indemnification agreements in excess of applicable insurance coverage is minimal.

Convertible Preferred Stock

Convertible Preferred Stock	9 Months Ended	12 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
Equity [Abstract]
Convertible Preferred Stock	9 . Convertible Preferred Stock Convertible preferred stock as of December 31, 2019 consisted of the following (in thousands, except share amounts): Convertible Shares Issued and Aggregate Liquidation Preferred Stock Authorized Outstanding Carrying Value Preference Series A 1,714,963 1,534,885 $ 15,163 $ 15,215 Series A-1 1,082,501 1,082,501 1,888 1,073 Total 2,797,464 2,617,386 $ 17,051 $ 16,288 In May and June 2020, the Company issued an aggregate of 9,372,765 shares of its Series B convertible preferred stock at a purchase price of $9.12 per share for aggregate proceeds of $81.6 million, net of offering costs. The Company issued warrants to purchase 2,343,168 shares of its common stock, of which 688,067 were exercised concurrently with the shares of Series B convertible preferred stock issuance, for net proceeds of $55,000. In addition, the Company issued warrants to purchase 127,481 shares of its Series B convertible preferred stock at a purchase price of $9.12 per share. The Series B convertible preferred stock financing triggered the automatic conversion of the Company’s outstanding convertible promissory notes into 512,858 shares of Series B-1 convertible preferred stock based on a price of $7.752 per share (85% of the $9.12 original issuance price of the Series B convertible preferred stock). In September 2020, upon the consummation of the Company’s IPO, all outstanding shares of convertible preferred stock converted into 12,503,009 shares of common stock.	10. Convertible Preferred Stock Convertible preferred stock as of December 31, 2018 and 2019 consisted of the following (in thousands, except share amounts): Convertible Shares Shares Issued and Carrying Value at December 31, Aggregate Liquidation Preferred Stock Authorized Outstanding 2018 2019 Preference Series A 1,714,963 1,534,885 $ 15,163 $ 15,163 $ 15,215 Series A-1 1,082,501 1,082,501 1,888 1,888 1,073 Total 2,797,464 2,617,386 $ 17,051 $ 17,051 $ 16,288 The rights, preferences, and privileges of the Series A and Series A-1 convertible preferred stock (collectively, Preferred Stock) are as follows: Dividends The holders of shares of Series A and Series A-1 Preferred Stock are entitled to receive non-cumulative dividends and non-dividend distributions in preference to any dividend or non-dividend distribution on the common stock, when, and if declared by the Company’s board of directors. Such dividend and non-dividend distribution preference survives until the holders of the Series A Preferred Stock and Series A-1 Preferred Stock have received a per share amount equal to: (a) in the case of dividends, 1.32 times the Series A Purchase Price or Series A-1 Purchase Price, as applicable, or (b) in the case of non-dividend distributions, the Series A Purchase Price or Series A-1 Purchase Price, as applicable. Conversion Preferred Stock will automatically convert into shares of common stock on a 1:1 basis upon the earlier to occur: (a) after the payment of the distribution preference to the holders of the Series A and Series A-1 Preferred Stock, and (b) upon the closing of a firmly underwritten public offering pursuant to an effective registration statement covering the offer and sale of common stock in which the gross proceeds to the Company are at least $50.0 million. The conversion ratio will be adjusted in the case of specified changes to the Company’s capitalization as a result of stock splits, combinations, common stock dividends and distributions, reclassifications, exchanges, substitutions, reorganizations, mergers or consolidations. In addition to the automatic conversion, the holders of Series A and Series A-1 Preferred Stock have the right to convert such shares, at any time, into shares of common stock. The initial conversion rate shall be 1:1, subject to any adjustments for stock splits, combinations, common stock dividends and distributions, reclassifications, exchanges, substitutions, reorganizations, mergers or consolidations. Dividends and Distributions After Conversion After such conversions, the holders of common stock (including the holders of common stock issued upon conversion of the Series A and Series A-1 Preferred Stock) are entitled to participate pro rata in any dividends or non-dividend distributions paid on the Common Stock, when, as and if declared by the board of directors. Liquidation, Acquisition or Asset Sale In the event of any liquidation or winding up of the Company, or upon an acquisition of the Company or the sale or other disposition of substantially all of the Company’s assets, the proceeds shall be paid first to the holders of the Series A and Series A-1 Preferred Stock equal to their purchase price, less any declared and paid dividends or non-dividend distributions. Any remaining amounts shall be distributed to the holders of the common stock, Series A Preferred Stock and Series A-1 Preferred Stock on a pro rata basis. The liquidation preference is less than the carrying value of the Series A-1 preferred stock as a portion of the carrying value originated from an $815,000 beneficial conversion feature recorded upon issuance of the underlying shares. Voting Each holder has one vote for each share of Series A or Series A-1 Preferred Stock. Classification Upon the occurrence of certain change in control events that are outside the Company’s control, including liquidation, sale or transfer of the Company, holders of the convertible preferred stock can effectively cause redemption for cash. As a result, the Company has classified the convertible preferred stock as mezzanine equity on the balance sheets as the stock is contingently redeemable. The Company has elected not to adjust the carrying values of the convertible preferred stock to the liquidation preferences of such shares because it is uncertain whether or when an event would occur that would obligate the Company to pay the liquidation preferences to holders of shares of convertible preferred stock. Subsequent adjustments to the carrying values to the liquidation preferences will be made only when it becomes probable that such a liquidation event will occur.

Common Stock

Common Stock	9 Months Ended	12 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
Equity [Abstract]
Common Stock	1 0 . Common Stock Each share of common stock has the right to one vote. The holders of common stock are also entitled to receive dividends whenever funds are legally available and if declared by the board of directors, subject to the prior rights of holders of all classes of stock outstanding having priority rights as to dividends. No cash dividends have been declared by the board of directors from inception. The Company has reserved the following shares of common stock for future issuance, on an as-converted basis, as follows: As of December 31, 2019 As of September 30, 2020 Convertible preferred stock 2,617,386 — Stock options outstanding 1,514,770 1,927,428 Shares available for future grant under the 2020 Equity Incentive Plan 399,737 3,790,279 Shares available for future grant under the Employee Stock Purchase Plan — 323,000 Common stock warrants 3,310 — Total 4,535,203 6,040,707	11. Common Stock Each share of common stock has the right to one vote. The holders of common stock are also entitled to receive dividends whenever funds are legally available and if declared by the board of directors, subject to the prior rights of holders of all classes of stock outstanding having priority rights as to dividends. No cash dividends have been declared by the board of directors from inception. The Company has reserved the following shares of common stock for future issuance, on an as-converted basis, as follows: As of December 31, 2018 2019 Convertible preferred stock 2,617,386 2,617,386 Stock options outstanding 1,263,831 1,514,770 Shares available for future grant 220,675 399,737 Common stock warrants 3,310 3,310 Total 4,105,202 4,535,203 Common stock warrants are exercisable at a price of $7.93 per share through April 8, 2021.

Stock-based Compensation

Stock-based Compensation	9 Months Ended	12 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock-based Compensation	1 1 . Stock-based Compensation Stock‑based compensation expense recognized was as follows (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2019 2020 2019 2020 Research and development $ 13 $ 43 $ 42 $ 62 General and administrative 56 68 147 156 Total stock-based compensation expense $ 69 $ 111 $ 189 $ 218 Valuation Assumptions The fair value of stock options was determined using the Black-Scholes option-pricing model and the assumptions below. Each of these inputs is subjective and generally required significant judgment. • Fair Value of Common Stock —The grant date fair market value of the shares of common stock underlying stock options has historically been determined by the Company’s board of directors. Because previously there was no public market for the Company’s common stock, the board of directors exercised reasonable judgment and considered a number of objective and subjective factors to determine the best estimate of the fair market value, which include contemporaneous valuations performed by an independent third party, important developments in the Company’s operations, sales of convertible preferred stock, the rights, preferences and privileges of its convertible preferred stock relative to those of its common stock, lack of marketability of its common stock, actual operating results, financial performance, the progress of clinical development, the likelihood of achieving a liquidity event for its security holders, the trends, development and conditions in the life sciences and biotechnology sectors, the economy in general, and the stock price performance and volatility of comparable public companies. • 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 the option. • Expected Volatility —Because the Company was previously privately held 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 life sciences companies over a period equal to the expected term of the stock option grants. The comparable companies were chosen based on the similar size, stage in 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 Term —The expected term represents the period that the stock-based awards are expected to be outstanding and is determined using the simplified method (based on the midpoint between the vesting date and the end of the contractual term) as the Company has limited history of relevant stock option exercise activity. • Expected Dividend Yield —The Company has never paid dividends on its common stock and has no plans to pay dividends going forward. Therefore, it used an expected dividend yield of zero. The fair value of each stock option was estimated using the Black‑Scholes option‑pricing model with the following weighted-average assumptions: Nine Months Ended September 30, 2019 2020 Risk-free interest rate 1.58 % 0.49 % Expected volatility 74.59 % 80.11 % Expected term (in years) 6.59 6.93 Expected dividend yield — — The weighted-average grant-date fair value of options granted to employees and directors during the nine months ended September 30, 2019 and 2020 were $259,000 and $2.1 million respectively. The remeasured weighted-average fair value of options granted to advisors during the nine months ended September 30, 2019 was $46,000. The weighted-average grant-date fair value of options granted to advisors during the nine months ended September 30, 2020 was $727,000. Stock Option Activity A summary of option activity for the nine months ended September 30, 2020 was as follows: Available for Grant Shares Weighted- Average Exercise price per Share Weighted- Average Remaining Contractual Term (in years) Aggregate Intrinsic Value (in thousands) Balance at December 31, 2019 399,737 1,514,770 $ 1.03 7.16 $ 500 Authorized 4,343,534 — Granted (994,293 ) 994,293 16.20 Exercised — (540,334 ) 1.00 Forfeited/expired 41,301 (41,301 ) 1.35 Balance at September 30, 2020 3,790,279 1,927,428 $ 8.85 8.18 $ 18,521 Expected to vest 1,298,059 $ 12.71 9.52 $ 7,460 Options exercisable 629,373 $ 0.89 5.43 $ 11,061 The total fair value of options granted to employees, directors, and advisors that vested during the nine months ended September 30, 2020 was $219,000, which included $144,000 for options granted to employees and directors and $75,000 for options granted to advisors. The total fair value of options that vested during the nine months ended September 30, 2019 was $123,000, which included $64,000 for options granted to employees and directors and $59,000 for options granted to advisors. The aggregate intrinsic value in the table above is calculated as the difference between the exercise price of the underlying options and the estimated fair value of the Company’s common stock underlying all options that were in-the-money at September 30, 2020. The aggregate intrinsic value of options exercised was $4,000 and $9.4 million during the nine months ended September 30, 2019 and 2020, respectively, determined as of the date of option exercise. As of September 30, 2020, there was $2.9 million of total unrecognized compensation cost related to unvested stock options. The Company expects to recognize this cost over a remaining weighted-average period of 1.95 years. The Company utilizes newly issued shares to satisfy option exercises. Stock options outstanding and exercisable consisted of the following at September 30, 2020: Employees and Directors Non-employees Exercise Price ($) Shares Outstanding Shares Exercisable Shares Outstanding Shares Exercisable 0.16 75,660 75,660 12,611 12,611 0.48 162,353 162,353 — — 1.00 — — 37,830 37,830 1.04 70,933 70,933 31,525 31,525 1.19 52,645 38,878 34,677 34,677 1.31 63,050 63,050 — — 1.35 294,754 27,529 116,642 63,049 1.49 31,525 10,508 — — 17.00 747,770 770 195,453 — Total 1,498,690 449,681 428,738 179,692 Restricted Stock Award Activity In 2018, the Company issued a restricted stock award (“RSA”) to an advisor under the 2014 Plan. The restricted stock award vests over three years and requires continued service to the Company during the vesting period. The vesting provisions of individual awards may vary as approved by the board of directors. If continued service terminates for any reason, the Company has the right to repurchase the unvested shares for no consideration. Shares subject to repurchase as of December 31, 2019 and September 30, 2020 were 8,407 shares and 4,204 shares, respectively, all of which were related to non-employee RSAs. A summary of RSA activity for the nine months ended September 30, 2020 was Share Equivalent Weighted- Average Grant Date Fair Value Non-vested at December 31, 2019 8,407 1.35 Granted — — Vested (4,203 ) 1.35 Non-vested at September 30, 2020 4,204 $ 1.35	12. Stock-based Compensation The Company maintains the 2014 Equity Incentive Plan (“2014 Plan”), as amended in August 2016, which allows for the grant of incentive stock options, non-statutory stock options, stock appreciation rights, restricted stock awards, and restricted stock unit awards to employees, officers, non-employee directors, consultants and advisors. As of December 31, 2019, the Company has reserved 3,076,214 shares of common stock for issuance under the 2014 Plan. The Company grants stock options with exercise prices equal to the estimated fair value of common stock on the date of the grant as determined by the board of directors based on the most recent third-party valuation of the common stock. Terms of stock award agreements, including vesting requirements, are determined by the board of directors, subject to the provisions of the plan, and typically have a contractual term of ten years from the date of grant. In the case of options granted to holders of more than 10% of the voting power of the Company, the exercise price may not be less than 110% of the fair market value of the common stock on the date the option is granted, and the term of the option may not exceed five years. Stock options granted have multiple vesting schedules ranging from immediate 100% vesting to cliff vesting ratably over four years. Restricted stock awards are awards of a specific number of shares of the Company’s common stock, and are subject to continued service and vesting conditions. Stock-based Compensation Expense Stock‑based compensation expense recognized was as follows (in thousands): Year Ended December 31, 2018 2019 Research and development $ 53 $ 55 General and administrative 143 198 Total stock-based compensation expense $ 196 $ 253 Valuation Assumptions The fair value of stock options was determined using the Black-Scholes option-pricing model and the assumptions below. Each of these inputs is subjective and generally required significant judgment. • Fair Value of Common Stock —The grant date fair market value of the shares of common stock underlying stock options has historically been determined by the Company’s board of directors. Because there has been no public market for the Company’s common stock, the board of directors exercises reasonable judgment and considers a number of objective and subjective factors to determine the best estimate of the fair market value, which include contemporaneous valuations performed by an independent third-party, important developments in the Company’s operations, sales of convertible preferred stock, the rights, preferences and privileges of the Company’s convertible preferred stock relative to those of its common stock, lack of marketability of its common stock, actual operating results, financial performance, the progress of clinical development, the likelihood of achieving a liquidity event for the Company’s security holders, the trends, development and conditions in the life sciences and biotechnology sectors, the economy in general, the stock price performance and volatility of comparable public companies. • 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 the option. • Expected Volatility —Because the Company has been privately held and does not have any trading history for its common stock, the expected volatility was estimated based on the average volatility for comparable publicly traded life sciences companies over a period equal to the expected term of the stock option grants. The comparable companies were chosen based on the similar size, stage in 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 Term —The expected term represents the period that the stock-based awards are expected to be outstanding and is determined using the simplified method (based on the mid-point between the vesting date and the end of the contractual term) as the Company has limited history of relevant stock option exercise activity. • 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, it used an expected dividend yield of zero. The fair value of each stock option was estimated using the Black‑Scholes option‑pricing model with the following weighted-average assumptions: Year Ended December 31, 2018 2019 Risk-free interest rate 2.6 % 1.6 % Expected volatility 76.3 % 75.0 % Expected term (in years) 6.6 6.5 Expected dividend yield — — The weighted-average grant-date fair value of options granted to employees and directors during the years ended December 31, 2018 and 2019 were $0.79 and $0.89, respectively. The re-measured weighted-average fair value of options granted to advisors during the years ended December 31, 2018 and 2019 were $1.08 and $1.06, respectively. Stock Option Activity A summary of option activity was as follows: Available for Grant Shares Weighted- Average Exercise Price Per Share Weighted- Average Remaining Contractual Term (in years) Aggregate Intrinsic Value (in thousands) Balance at December 31, 2018 220,675 1,263,831 $ 0.93 Authorized 511,966 Granted (351,819 ) 351,819 1.35 Exercised (81,965 ) 0.89 Forfeited/expired 18,915 (18,915 ) 1.35 Balance at December 31, 2019 399,737 1,514,770 $ 1.03 7.16 $ 500 Expected to vest 593,093 $ 1.35 8.79 $ 18 Options exercisable 921,677 $ 0.83 6.11 $ 477 The total fair value of options granted to employees, directors, and advisors that vested during the year ended December 31, 2018 was $160,000, which included $115,000 for options granted to employees and directors and $45,000 for options granted to advisors. The total fair value of options that vested during the year ended December 31, 2019 was $183,000, which included $104,000 for options granted to employees and directors and $79,000 for options granted to advisors. The aggregate intrinsic value in the table above is calculated as the difference between the exercise price of the underlying options and the estimated fair value of the Company’s common stock for all options that were in-the-money at December 31, 2019. The aggregate intrinsic value of options exercised was $297,000 during 2018 and $38,500 during 2019, determined as of the date of option exercise. As of December 31, 2019, there was $374,000 of total unrecognized compensation cost related to unvested stock options. The Company expects to recognize this cost over a remaining weighted-average period of 1.41 years. The Company utilizes newly issued shares to satisfy option exercises. Stock options outstanding and exercisable consisted of the following at December 31, 2019: Employees and Directors Non-employees Exercise Price ($) Share Options Outstanding Share Options Exercisable Share Options Outstanding Share Options Exercisable 0.16 75,660 75,660 15,762 15,762 0.48 288,453 288,453 — — 1.00 — — 37,830 37,830 1.04 241,164 194,139 81,965 81,964 1.19 66,517 47,392 34,677 34,677 1.31 63,050 63,050 — — 1.35 414,237 22,067 163,930 60,684 1.49 31,525 — — — Total 1,180,606 690,760 334,164 230,917 Restricted Stock Award Activity In 2018, the Company issued a restricted stock award (“RSA”) to an advisor under the 2014 Plan. The restricted stock award vests over three years and requires continued service to the Company during the vesting period. The vesting provisions of individual awards may vary as approved by the board of directors. If continued service terminates for any reason, the Company has the right to repurchase the unvested shares for no consideration. As of December 31, 2019, there were 8,407 shares subject to repurchase, all of which were related to non-employee RSAs and have been excluded from the weighted-average number of shares outstanding for the purposes of calculating earnings per share. A summary of RSA activity was as follows: Share Equivalent Weighted- Average Grant Date Fair Value Non-vested at December 31, 2018 12,610 $ 1.35 Granted — — Vested (4,203 ) 1.35 Non-vested at December 31, 2019 8,407 $ 1.35 As of December 31, 2019, there was approximately $6,000 of total unrecognized compensation cost related to non-vested restricted stock awards that will be recognized as expense over a weighted-average period of 1.23 years.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Income Taxes	13. Income Taxes Components of Income and Income Tax All components of net loss before the effects of the income tax provision are related to losses incurred in the United States. The Company did not record a provision (benefit) for income taxes for the years ended December 31, 2018 and 2019. The provision for income taxes differs from the amount expected by applying the federal statutory rates to the net loss before taxes as follows: Year Ended December 31, 2018 2019 Federal statutory income tax rate 21.0 % 21.0 % Non-deductible expenses and others 0.2 (0.6 ) Non-deductible expense related to the convertible notes and derivative liability — (1.7 ) Non-deductible expense related to the grant liability — (0.3 ) Tax credits 2.8 2.2 Change in valuation allowance (24.0 ) (20.6 ) Effective income tax rate — % — % Significant Components of Deferred Taxes The components of the Company’s deferred tax assets were as follows (in thousands): Year Ended December 31, 2018 2019 Deferred tax assets: Net operating loss carryforwards $ 3,032 $ 3,911 Research and development tax credit carryforwards 600 716 Accrued liabilities and other 47 93 Stock-based compensation 60 82 Total deferred tax assets 3,739 4,802 Deferred tax liabilities: Prepaid expenses and other (13 ) (12 ) Total deferred tax liabilities (13 ) (12 ) Less valuation allowance (3,726 ) (4,790 ) Net deferred tax assets $ — $ — Deferred income taxes reflect temporary differences between the carrying amounts of assets and liabilities for financial reporting and income tax purposes, and operating losses and tax credit carryforwards. The Company considers a number of factors concerning the realizability of its net deferred tax assets, including its history of operating losses, the nature of the deferred tax assets, and the timing, likelihood and amount, if any, of future taxable income during the periods in which those temporary differences and carryforwards become deductible, all of which require significant judgment. As of December 31, 2019, the Company has recorded a full valuation allowance on its net deferred tax assets as the Company has concluded that it is not more likely than not that such losses or credits will be utilized. The valuation allowance increased by $1.2 million and $1.1 million during 2018 and 2019, respectively. At December 31, 2019, the Company has federal net operating loss and tax credit carryforwards of $9.4 million and $1.0 million, respectively, which expire over a period of 11 to 20 years. Net operating loss carryforwards of $9.2 million were generated after 2017, and therefore do not expire. Uncertain Tax Positions The Company files federal income tax returns. With few exceptions, the Company is no longer subject to income tax examinations by tax authorities for years prior to 2016. However, to the extent allowed by law, the tax authorities may have the right to examine prior periods where net operating losses or tax credits were generated and carried forward and may make adjustments to the amount of the net operating loss or credit carryforward amount. The Company is not currently under examination in any jurisdiction. A reconciliation of the beginning and ending amount of unrecognized tax benefits were as follows (in thousands): Year Ended December 31, 2018 2019 Beginning balance $ 152 $ 200 Additions for tax positions taken in the current year 48 39 Ending balance $ 200 $ 239 If the unrecognized tax benefits for uncertain tax positions as of December 31, 2019 are recognized, there will be no impact to the effective tax rate due to the valuation allowance. The Company recognizes interest and penalties related to unrecognized tax benefits within the income tax expense line in the accompanying financial statements. At December 31, 2019, there were no material interest and penalties on uncertain tax benefits. The Company does not anticipate any significant changes to its unrecognized tax benefits in the next 12 months.

Employee Benefit Plans

Employee Benefit Plans	12 Months Ended
	Dec. 31, 2019
Employee Benefit Plans [Abstract]
Employee Benefit Plans	14. Employee Benefit Plans The Company has a 401(k) Plan for all of its employees. The 401(k) Plan allows eligible employees to defer, at the employee’s discretion, up to 100% of their pretax compensation up to the Internal Revenue Service annual limit. The Company did not make any matching contributions for the years ended December 31, 2018 or 2019.

Net Loss Per Share Attributable

Net Loss Per Share Attributable to Common Stockholders	9 Months Ended	12 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
Earnings Per Share [Abstract]
Net Loss Per Share Attributable to Common Stockholders	1 2 . Net Loss Per Share Attributable to Common Stockholders The following outstanding shares of potentially dilutive securities were excluded from the computation of the diluted net loss per share attributable to common stockholders for the periods presented because their effect would have been anti-dilutive: Nine Months Ended September 30, 2019 2020 Convertible preferred stock on an as-converted basis 2,617,386 — Unvested RSAs 8,407 4,204 Stock options to purchase common stock 1,498,377 1,927,428 Common stock warrants 3,310 — Total 4,127,480 1,931,632	15. Net Loss Per Share Attributable to Common Stockholders The following outstanding shares of potentially dilutive securities were excluded from the computation of the diluted net loss per share attributable to common stockholders for the periods presented because their effect would have been anti-dilutive: Year Ended December 31, 2018 2019 Convertible preferred stock on an as-converted basis 2,617,386 2,617,386 Unvested RSAs 12,610 8,407 Stock options to purchase common stock 1,263,831 1,514,770 Common stock warrants 3,310 3,310 Total 3,897,137 4,143,873 16. Unaudited Pro Forma Net Loss Per Share Attributable to Common Stockholders Pro forma basic and diluted net loss per share has been computed to give effect to the assumed conversion of all outstanding convertible preferred stock into shares of common stock, the net exercise of the outstanding warrants for shares of common stock and the repayment of the grant liability upon completion of a qualifying IPO of the Company’s common stock. The following table sets forth the computation of the unaudited pro forma basic and diluted net loss per share attributable to common stockholders (in thousands, except share and per share data): Year Ended December 31, 2019 (unaudited) Numerator: Net loss $ (5,161 ) Loss on remeasurement of grant liability 100 Net loss used in computing pro forma net loss per share attributable to common stockholders, basic and diluted (5,061 ) Denominator: Weighted-average shares of common stock used in computing net loss per share attributable to common stockholders 3,566,849 Pro forma adjustment to reflect conversion of convertible preferred stock 2,617,386 Pro forma adjustment to reflect net exercise of common stock warrants 2,309 Weighted-average shares of common stock used in computing pro forma net loss per share attributable to common stockholders, basic and diluted 6,186,544 Pro forma net loss per share attributable to common stockholders, basic and diluted $ (0.82 )

Subsequent Events

Subsequent Events	9 Months Ended	12 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
Subsequent Events [Abstract]
Subsequent Events	1 3 . Subsequent Events Exercise of Underwriters’ Option On October 16, 2020, the Company sold an additional 1,397,712 shares of common stock to the underwriters of the IPO upon partial exercise of the underwriters’ option to purchase additional shares at the initial public offering price of $17.00 per share, less underwriting discounts and commissions, resulting in net proceeds to the Company of approximately $22.1 million.	17. Subsequent Events For the year ended December 31, 2019, management evaluated subsequent events through July 24, 2020, the date these financial statements were issued, and September 14, 2020, the date the revised financial statements were issued. The Company has concluded that no events or transactions have occurred that require disclosure in the accompanying financial statements, other than the following. (a) Stock Option Grants Subsequent to December 31, 2019, the Company granted 44,765 stock options with an exercise price of $1.35 per share. In September 2020, the board of directors of the Company approved option awards to purchase an aggregate of 943,223 shares of common stock to certain executives, employees, advisors and non-employee directors of the Company. These awards will be issued under the 2020 Equity Incentive Plan and are subject to and will become effective upon the effectiveness of the Company’s registration statement. The exercise price of each option will be equal to the initial price of a share of the Company’s common stock to the public as of the effective date of the registration statement. (b) Convertible Notes The Company issued $1.7 million of additional convertible notes during January 2020, including $250,000 of convertible notes to the Company’s chief operating officer and affiliates, which the Company has determined to be related parties. (c) Paycheck Protection Program The Company received a loan of $215,000 from the U.S. Small Business Administration Paycheck Protection Program (“PPP”) in April 2020. The PPP loans are intended to assist companies impacted by the COVID-19 pandemic to fund certain types of expenditures, including payroll costs, rent and utility payments. PPP loans and any accrued interest may be forgiven to the extent that all employees are retained, proceeds are used within eight weeks of receipt, and if at least 75% of the loan amount utilized was for payroll costs. The loan bears interest at a rate of 1%, and any portion of the loan not forgiven and any accrued interest thereon must be repaid within two years. The loan was fully repaid in June 2020. (d) COVID-19 Management continues to evaluate the potential impacts of the COVID-19 pandemic on the development of its product candidates, and business. The Company is working closely with its manufacturing vendors to maintain adequate product supply and with healthcare providers as future studies are planned to mitigate risk to patients while adhering to regulatory, institutional and government guidance and policies. The Company remains committed to its development plans and acknowledges the potential risk for delays in the product supply chain and in anticipated timelines for its preclinical studies and clinical trials. (e) Convertible Preferred Stock In May and June 2020, the Company issued an aggregate of 9,372,765 shares of Series B convertible preferred stock at a purchase price of $9.12 per share for proceeds of $81.8 million, net of offering costs. The Company issued warrants to purchase 2,343,168 shares of its common stock, of which 688,067 shares were exercised concurrently with the Series B convertible preferred stock issuance for net proceeds of $55,000. In addition, the Company issued warrants to purchase 127,481 shares of its Series B convertible preferred stock at $9.12 per share. The Series B convertible preferred stock financing triggered the automatic conversion of the Company’s then outstanding convertible promissory notes into an aggregate of 512,858 shares of Series B-1 convertible preferred stock based on a price of $7.752 per share (85% of the $9.12 original issuance price of the Series B convertible preferred stock). (f) Athira Pharma Australia PTY LTD In July 2020, the Company established Athira Pharma Australia PTY LTD, a subsidiary, to facilitate clinical trials in Australia. As of the date hereof, research and development operations have not commenced in Australia. (g) Employee Stock Purchase Plan In September 2020, the board of directors of the Company approved the Employee Stock Purchase Plan (the “ESPP”). The ESPP will become effective on the date immediately prior to the effectiveness of the Company’s registration statement on Form S-1 for its proposed IPO. The ESPP provides for the issuance of up to 323,000 shares of common stock. (h) Reverse Stock Spilt In September 2020, the board of directors of the Company approved an amendment to the Company’s certificate of incorporation to effect a reverse split of shares of the Company’s common stock and preferred stock on a 7.9302-for-one basis, which was effected on September 11, 2020. All references to convertible preferred stock, common stock, warrants to purchase convertible preferred stock, warrants to purchase common stock, options to purchase common stock, restricted stock awards, per share amounts and related information contained in the financial statements have been retroactively adjusted to reflect the effect of the reverse stock split for all periods presented. (i) National Institutes of Health Grant In September 2020, the Company was awarded a $7.8 million grant from the National Institute on Aging of the National Institutes of Health under award R01AG068268 for the period September 15, 2020 through May 31, 2021.

Debt

Debt	9 Months Ended
	Sep. 30, 2020
Debt Disclosure [Abstract]
Debt	7 . Debt Convertible Notes The Company issued unsecured convertible notes with an aggregate principal amount of $1.7 million in 2020. Previously, the Company issued unsecured convertible notes with aggregate principal amounts of $884,000 and $1.3 million and in 2019 and 2018, respectively. The notes accrue interest at a rate of 5% per year and mature in December 2021, unless earlier converted. No principal or interest is payable prior to maturity as the convertible notes and any accrued interest will automatically convert upon a qualified financing event at a conversion price equal to 85% of the price per share of the qualified financing. Holders may also elect to convert their notes to shares of common stock upon the maturity of the notes at the then fair value of common stock. If the Company experiences a change in control, holders may either convert the outstanding principal amount plus any accrued interest into shares of common stock at the then fair value of common stock or may require the Company to repurchase the notes in cash at a price equal to 200% of the outstanding principal amount plus any accrued interest. Certain conversion and redemption features as described above were determined to be an embedded derivative requiring bifurcation and separate accounting in accordance with ASC 815, Derivatives and Hedging In May 2020, the outstanding principal balance of the convertible notes of $3.8 million and accrued interest of $160,000 converted into 512,858 shares of Series B-1 convertible preferred stock. The excess of the carrying value of the convertible notes and the derivative liability over the fair value of the Series B-1 convertible preferred stock at conversion resulted in a gain upon extinguishment of $199,000. Paycheck Protection Program The Company received a loan of $215,000 from the U.S. Small Business Administration Paycheck Protection Program (“PPP”) in April 2020. The PPP loans are intended to assist companies impacted by the novel coronavirus disease (“COVID-19”) pandemic to fund certain types of expenditures, including payroll costs, rent and utility payments. PPP loans and any accrued interest may be forgiven to the extent that all employees are retained, proceeds are used within eight weeks of receipt, and if at least 75% of the loan amount utilized was for payroll costs. The loan bears interest at a rate of 1%, and any portion of the loan not forgiven and any accrued interest thereon must be repaid within two years. The loan was fully repaid in June 2020.

Leases

Leases	9 Months Ended
	Sep. 30, 2020
Leases [Abstract]
Leases	8. Leases Operating Leases The Company has an operating lease for laboratory and office facilities in Bothell, Washington that expires in August 2027. The initial term of the lease is seven years and the Company has an option to extend the lease for an additional five years that it is not reasonably certain to exercise. As of September 30, 2020, the remaining lease term for the Company’s operating lease was 6.9 years. The Company discounted future operating lease payments using an incremental borrowing rate of 8.2%. Additionally, the Company has a lease agreement for laboratory and office facilities at the University of Washington in Seattle, Washington with an initial term of 12 months for which the Company recognizes expense on a straight-line basis within operating expenses. As of September 30, 2020, the Company was not party to any finance leases. The following table reconciles the Company’s undiscounted operating lease cash flows to its operating lease liability (in thousands): As of September 30, 2020 Remaining 2020 $ — 2021 234 2022 261 2023 269 2024 277 2025 and thereafter 779 Total undiscounted lease payments 1,820 Present value adjustment for minimum lease commitments (457 ) Tenant improvement allowance receivable (391 ) Net lease liability $ 972 Operating lease expense was $34,000 for the three and nine months ended September 30, 2020. The Company did not incur variable lease expense for operating leases during the three and nine months ended September 30, 2020. Rent expense recognized for short term leases was $18,000 and $57,000 for the three and nine months ended September 30, 2020, respectively. Cash paid for amounts included in the measurement of the lease liability for the nine months ended September 30, 2020 was $21,000.

Significant Accounting Polici_2

Significant Accounting Policies (Policies)	9 Months Ended	12 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The condensed consolidated financial statements have been prepared in conformity with U.S. generally accepted accounting principles (“U.S. GAAP”). During the third quarter of 2020, the Company incorporated Athira Pharma Australia PTY LTD in Australia and as of September 30, 2020, operations have yet to commence.	Basis of Presentation The financial statements have been prepared in conformity with U.S. generally accepted accounting principles (“U.S. GAAP”).
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of expenses during the reporting period. Estimates include those used for fair value of assets and liabilities, accrued liabilities, valuation allowance for deferred tax assets, and stock-based compensation. Management evaluates related assumptions on an ongoing basis using historical experience and other factors, and adjusts those estimates and assumptions when facts and circumstances dictate.	Use of Estimates The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of expenses during the reporting period. Estimates include those used for fair value of assets and liabilities, accrued liabilities, valuation allowance for deferred tax assets, and stock-based compensation. Management evaluates related assumptions on an ongoing basis using historical experience and other factors, and adjusts those estimates and assumptions when facts and circumstances dictate.
Cash and Cash Equivalents		Cash and Cash Equivalents The Company considers highly liquid investments with original maturities of three months or less to be cash equivalents.
Short-term and Long-term Investments	Short-term and Long-term Investments The Company generally invests its excess cash in investment grade short- to intermediate-term fixed income securities. Such investments are included in cash and cash equivalents, short-term investments, and long-term investments on the consolidated balance sheets, classified as available-for-sale, and reported at fair value with unrealized gains and losses included in accumulated other comprehensive loss. Realized gains and losses on the sale of these securities are recognized in net loss. The Company periodically evaluates whether declines in fair values of its investments below their book value are other-than-temporary. This evaluation consists of several qualitative and quantitative factors regarding the severity and duration of the unrealized loss as well as the Company’s ability and intent to hold the investment until a forecasted recovery occurs. Additionally, the Company assesses whether it has plans to sell the security or it is more likely than not it will be required to sell any investment before recovery of its amortized cost basis. Factors considered include quoted market prices, recent financial results and operating trends, implied values from any recent transactions or offers of investee securities, credit quality of debt instrument issuers, other publicly available information that may affect the value of the investments, duration and severity of the decline in value, and our strategy and intentions for holding the investment.	Short-term Investments Short-term investments consist entirely of fixed income certificates of deposit with original maturities of greater than 90 days but not more than one year. These securities are classified as available-for-sale and reported at estimated fair value with unrealized gains and losses, if any, included in accumulated other comprehensive loss in stockholders’ deficit. The cost of investments for purposes of computing realized and unrealized gains and losses is based on the specific identification method. If the estimated fair value of a security is below its carrying value, the Company evaluates whether it is more likely than not that it will sell the security before its anticipated recover in market value and whether evidence indicating that the cost of the investment is recoverable within a reasonable period of time outweighs the evidence to the contrary. Realized gains, realized losses and declines in the value of investments judged to be other than temporary, are included in other income (expense), net.
Concentration of Credit Risk		Concentration of Credit Risk The Company is exposed to credit risk from its deposits of cash in excess of amounts insured by the Federal Deposit Insurance Corporation. The Company has not experienced any losses on its deposits of cash since inception.
Fair Value Measurements	Fair Value Measurements The carrying amounts of certain financial instruments, including cash and cash equivalents, accounts payable and accrued expenses approximate their fair values due to the short-term nature of those amounts. The fair values of the grant liability to Life Sciences Discovery Fund (“LSDF”), the derivative liability, and the convertible preferred stock warrant liability were estimated using Level 3 unobservable inputs.	Fair Value Measurements The carrying amounts of certain financial instruments, including cash and cash equivalents, short-term investments, and accounts payable and accrued expenses approximate their fair values due to the short-term nature of those amounts. The fair values of the grant liability to Life Services Discovery Fund (“LSDF”) and the derivative liability were estimated using Level 3 unobservable inputs.
Grant Liability		Grant Liability The grant liability associated with the grants from the Washington LSDF is accounted for under Accounting Standards Codification (“ASC”) 825-10, Financial Instruments − Overall
Derivative Liability Convertible Notes Discount and Amortization		Derivative Liability, Convertible Notes Discount and Amortization The Company’s convertible notes (see Note 8) have conversion and redemption features that meet the definition of an embedded derivative and are therefore subject to derivative accounting. The initial fair value of the derivative is recorded as a discount to the convertible notes, with a corresponding derivative liability. The discount to the convertible notes is amortized using the effective interest method. The amortization of the discount is included in other income (expense), net in the statements of operations and comprehensive loss. The derivative liability related to these features is recorded at estimated fair value on a recurring basis. Any changes in fair value are reflected in other income (expense), net in the statements of operations and comprehensive loss at each period end while such instruments are outstanding. The derivative liability was settled in May 2020 upon conversion of the underlying convertible notes into Series B-1 convertible preferred stock. See Note 17.
Grant Income		Grant Income In January 2019, the Alzheimer’s Association awarded the Company a $1.0 million Part the Cloud
Research and Development Expenses	Research and Development Expenses Research and development expenses consist primarily of direct and indirect costs incurred for research activities, including development of our pipeline from the Company’s proprietary drug discovery platform (“ATH platform”). The Company’s drug discovery efforts and the development of its product candidates. Direct costs include laboratory materials and supplies, contracted research and manufacturing, clinical trial costs, consulting fees, and other expenses incurred to sustain the Company’s research and development program. Indirect costs include personnel-related expenses, consisting of employee salaries, related benefits, and stock-based compensation expense for employees engaged in research and development activities, and facilities and other expenses consisting of direct and allocated expenses for rent and depreciation and lab consumables. Research and development costs are expensed as incurred. In-licensing fees and other costs to acquire technologies used in research and development that have not yet received regulatory approval and that are not expected to have an alternative future use are expense when incurred. Non-refundable advance payments for goods and services that will be used over time for research and development are capitalized and recognized as goods are delivered or as the related services are performed. The Company estimates the period over which such services will be performed and the level of effort to be expended in each period. If actual timing of performance or the level of effort varies from the estimate, the Company adjusts the amounts recorded accordingly. The Company has not experienced any material differences between accrued or prepaid costs and actual costs since inception.	Research and Development Expenses Research and development expenses consist primarily of direct and indirect costs incurred for research activities, including development of the ATH platform, the Company’s drug discovery efforts and the development of its product candidates. Direct costs include laboratory materials and supplies, contracted research and manufacturing, clinical trial costs, consulting fees, and other expenses incurred to sustain the Company’s research and development program. Indirect costs include personnel-related expenses, consisting of employee salaries, related benefits, and stock-based compensation expense for employees engaged in research and development activities, and facilities and other expenses consisting of direct and allocated expenses for rent and depreciation and lab consumables. Research and development costs are expensed as incurred. In-licensing fees and other costs to acquire technologies used in research and development that have not yet received regulatory approval and that are not expected to have an alternative future use are expense when incurred. Non-refundable advance payments for goods and services that will be used over time for research and development are capitalized and recognized as goods are delivered or as the related services are performed. The Company estimates the period over which such services will be performed and the level of effort to be expended in each period. If actual timing of performance or the level of effort varies from the estimate, the Company will adjust the amounts recorded accordingly. The Company has not experienced any material differences between accrued or prepaid costs and actual costs since inception.
General and Administrative Expenses		General and Administrative Expenses General and administrative expenses consist primarily of personnel-related costs, consisting of employee salaries, related benefits, and stock-based compensation expense for employees in the executive, legal, finance and accounting, human resources, and other administrative functions. General and administrative expenses also include third-party costs such as legal costs, insurance costs, accounting, auditing and tax related fees, consulting fees and facilities and other expenses not otherwise included as research and development expenses. General and administrative costs are expensed as incurred.
Stock-based Compensation	Stock-based Compensation The Company measures compensation expense for all stock-based payments to employees, officers and directors based on the estimated fair value of the award at the grant date. For stock options, the Company estimates the grant date fair value of each option award using the Black-Scholes option-pricing model. Compensation expense is recognized over the requisite service period on a straight-line basis. Forfeitures are recognized as they occur. The Company records compensation expense for stock option grants subject to performance-based milestone vesting using the accelerated attribution method over the remaining service period when management determines that achievement of the milestone is probable. Management evaluates when the achievement of a performance-based milestone is probable based on the relative satisfaction of the performance conditions as of the reporting date. The Company adopted Accounting Standards Update (“ASU”) 2018-07 as of January 1, 2020. As a result, stock-based payments issued to non-employees prior to January 1, 2020 have been recorded at their fair values as of the transition date and are no longer subject to periodic adjustments as the underlying equity instruments vest. Any remaining compensation expense is recognized over the remaining vesting term on a straight-line basis, which reflects the service period, based on the fair value as of January 1, 2020.	Stock-based Compensation The Company measures compensation expense for all stock-based payments to employees, officers and directors based on the estimated fair value of the award at the grant date. For stock options, the Company estimates the grant date fair value of each option award using the Black-Scholes option-pricing model. Compensation expense is recognized over the requisite service period on a straight-line basis. Forfeitures are recognized as they occur. The Company records compensation expense for stock option grants subject to performance-based milestone vesting using the accelerated attribution method over the remaining service period when management determines that achievement of the milestone is probable. Management evaluates when the achievement of a performance-based milestone is probable based on the relative satisfaction of the performance conditions as of the reporting date. Stock-based payments issued to non-employees are recorded at their fair values, subject to periodic adjustments as the underlying equity instruments vest. Compensation expense is recognized over the vesting term on a straight-line basis, which reflects the service period. Options granted to non-employee service providers are valued at estimated fair value using the Black-Scholes option-pricing model and are remeasured over the vesting term as earned. Awards of restricted stock to non-employees are adjusted through stock-based compensation expense at each reporting period end until the shares vest to reflect the current fair value of such awards.
Income Tax		Income Taxes Income taxes are accounted for under the asset and liability method. Deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases and operating loss and tax credit carry forwards. Deferred tax assets and liabilities 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. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income in the period that includes the enactment date. In assessing the Company’s ability to realize deferred tax assets, management considers whether it is more likely than not that some portion or all of the deferred tax assets will not be realized. The ultimate realization of deferred tax assets is dependent upon the generation of future taxable income during the periods in which those temporary differences are deductible. Management considers the scheduled reversal of deferred tax liabilities, projected future income, tax planning strategies in making this assessment. The Company recognizes the effect of income tax positions only if those positions are more likely than not of being sustained. Recognized income tax positions are measured at the largest amount that is greater than 50% likely of being realized. Changes in recognition or measurement are reflected in the period in which the change in judgment occurs. The Company accrues interest and penalties related to unrecognized tax benefits in its provision for incomes taxes.
Comprehensive Loss		Comprehensive Loss Comprehensive loss consists of net loss and other gains and losses affecting stockholders’ deficit that, under U.S. GAAP, are excluded from net loss. The Company has no items of other comprehensive loss. As such, net loss equals comprehensive loss.
Net Loss Per Share Attributable to Common Stockholders	Net Loss Per Share Attributable to Common Stockholders Basic net loss per share attributable to common stockholders is calculated by dividing the net loss attributable to common stockholders by the weighted-average number of shares of common stock outstanding for the period, without consideration of potentially dilutive securities. Diluted net loss per share attributable to common stockholders is the same as basic net loss per share attributable to common stockholders since the effect of potentially dilutive securities is anti-dilutive given the net loss of the Company.	Net Loss Per Share Attributable to Common Stockholders Basic net loss per share attributable to common stockholders is calculated by dividing the net loss attributable to common stockholders by the weighted-average number of shares of common stock outstanding for the period, without consideration of potentially dilutive securities. Diluted net loss per share attributable to common stockholders is the same as basic net loss per share attributable to common stockholders since the effect of potentially dilutive securities is anti-dilutive given the net loss of the Company.
Unaudited Pro Forma Net Loss Per Share Attributable to Common Stockholders		Unaudited Pro Forma Net Loss Per Share Attributable to Common Stockholders The unaudited pro forma basic and diluted net loss per share attributable to common stockholders has been computed to give effect to the conversion of all shares of convertible preferred stock into common stock, the net exercise of outstanding warrants for shares of common stock, and the repayment of the grant liability upon the closing of a firm-commitment underwritten public offering (“IPO”) resulting in at least $50.0 million in gross proceeds. The unaudited pro forma net loss per share attributable to common stockholders does not include the shares to be sold from the proposed IPO.
Segments	Segments The Company has determined that it operates and manages one operating segment, which is the business of developing and commercializing therapeutics. The Company’s chief operating decision maker, its chief executive officer, reviews financial information on an aggregate basis for the purpose of allocating resources.	Segments The Company has determined that it operates and manages one operating segment, which is the business of developing and commercializing therapeutics. The Company’s chief operating decision maker, its chief executive officer, reviews financial information on an aggregate basis for the purpose of allocating resources.
Related Party Transactions		Related Party Transactions As of December 31, 2018 and 2019, the Company had an unsecured note receivable outstanding from its chief executive officer of approximately $42,000 and $36,000, respectively. The note bears interest at 1.45% and requires monthly payments with final repayment in April 2025. The note is included in current portion of unsecured related party note receivable and unsecured related party note receivable in the accompanying balance sheets. Interest income is recognized using the effective interest method, and is included in other income (expense), net in the statements of operations and comprehensive loss.
Emerging Growth Company Status	Emerging Growth Company Status The Company is an emerging growth company, as defined in the Jumpstart Our Business Startups Act of 2012 (“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 is (a) no longer an emerging growth company or (b) affirmatively and irrevocably opt out of the extended transition period provided in the JOBS Act. As a result, these financial statements may not be comparable to companies that comply with the new or revised accounting pronouncements as of public company effective dates.	Emerging Growth Company Status The Company is an emerging growth company, as defined in the Jumpstart Our Business Startups Act of 2012 (“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 is (a) no longer an emerging growth company or (b) affirmatively and irrevocably opt out of the extended transition period provided in the JOBS Act. As a result, these financial statements may not be comparable to companies that comply with the new or revised accounting pronouncements as of public company effective dates.
Recently Adopted Accounting Pronouncements Adopted and Not Yet Adopted	Recently Adopted Accounting Pronouncements In February 2016, the Financial Accounting Standards Board (“FASB”) issued ASU 2016-02, Leases (Topic 842) Leases (Topic 842) Targeted Improvements In adopting the new standard, the Company utilized certain practical expedients available. These practical expedients include waiving reassessment of 1) whether any expired or existing contracts are or contain leases; 2) lease classification of expired or existing leases; and 3) initial direct costs for existing leases. The Company also elected to use hindsight in determining the lease term and in assessing impairment of its ROU assets. Furthermore, the Company has made a policy decision regarding its real estate leases not to separate nonlease components from lease components, to the extent they are fixed. The Company has also elected not to record on the balance sheet a lease that has a lease term of 12 months or less and does not contain a purchase option that the Company is reasonably certain to exercise. The standard had a material impact on the Company’s unaudited condensed balance sheets but did not have a material impact on its unaudited condensed statements of operations or unaudited condensed statements of cash flows. The most significant impact was the recognition of $1.0 million and $1.0 million of operating lease ROU assets and liabilities, respectively. Refer to Note 8, Leases, for additional information regarding leases. In June 2018, the FASB issued ASU 2018-07, Compensation – Stock Compensation (Topic 326) Improvements to Nonemployee Share-Based Payment Accounting In August 2018, the FASB issued ASU 2018-13, Disclosure Framework – Changes to the Disclosure Requirements for Fair Value Measurement Recent Accounting Pronouncements Not Yet Adopted In June 2016, the FASB issued ASU 2016-13, Financial Instruments: Credit Losses (Topic 326)	Recent Accounting Pronouncements Not Yet Adopted In February 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2016-02, Leases In June 2016, the FASB issued ASU 2016-13, Financial Instruments: Credit Losses (Topic 326) In August 2018, the FASB issued ASU 2018-15, Intangible − Goodwill and Others − Internal-Use Software (Subtopic 350-40) Customer's Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract Disclosure Framework – Changes to the Disclosure Requirements for Fair Value Measurement In June 2018, the FASB issued ASU 2018-07, Compensation – Stock Compensation (Topic 326) Improvements to Nonemployee Share-Based Payment Accounting
Unaudited Interim Condensed Financial Statements	Unaudited Interim Condensed Financial Statements The accompanying unaudited condensed balance sheet as of September 30, 2020, and condensed statements of operations and comprehensive loss, condensed statements of cash flows, and condensed statements of convertible preferred stock and stockholders’ deficit for the three and nine months ended September 30, 2020 and 2019, are unaudited. The balance sheet as of December 31, 2019 was derived from the audited financial statements as of and for the year ended December 31, 2019. The unaudited interim condensed financial statements have been prepared on a basis consistent with the audited annual financial statements as of and for the year ended December 31, 2019, and, in the opinion of management, reflect all adjustments, consisting solely of normal recurring adjustments, necessary for the fair presentation of the Company’s financial position as of September 30, 2020, and the condensed results of its operations and its cash flows for the three and nine months ended September 30, 2020 and 2019. The financial data and other information disclosed in these notes related to the three and nine months ended September 30, 2020 and 2019 are also unaudited. The condensed results of operations for the three and nine months ended September 30, 2020 are not necessarily indicative of the results to be expected for the full year ending December 31, 2020 or any other period. These interim condensed financial statements should be read in conjunction with the Company’s audited financial statements included elsewhere in this prospectus.
Convertible Preferred Stock Warrant Liability	Convertible Preferred Stock Warrant Liability Freestanding warrants to purchase shares of the Company’s convertible preferred stock are accounted for as liabilities at fair value, because the shares underlying the warrants contain contingent redemption features outside the control of the Company. Warrants classified as liabilities are recorded on the Company’s balance sheets at their fair value on the date of issuance and remeasured to fair value on each subsequent reporting period, with the changes in fair value recognized as a component of other income (expense), net in the accompanying statements of operations. The Company will continue to adjust the liability for changes in the fair value of these warrants until the earlier of the exercise of the warrants, the expiration of the warrants, or until such time as the warrants are no longer considered liability instruments.
Leases	Leases As discussed in Recently Adopted Accounting Standards Topic 842 - Leases The Company’s lease contains an option to extend the lease; lease terms are adjusted for these options only when it is reasonably certain the Company will exercise these options. The Company’s lease agreement does not contain residual value guarantees or covenants. The Company has made a policy election regarding its real estate leases not to separate nonlease components from lease components, to the extent they are fixed. Nonlease components that are not fixed are expensed as incurred as variable lease expense. The Company’s lease includes variable nonlease components, such as common-area maintenance costs. The Company has elected not to record on the balance sheet a lease that has a lease term of 12 months or less and does not contain a purchase option that the Company is reasonably certain to exercise. The Company accounts for leases with initial terms of 12 months or less as operating expenses on a straight-line basis over the lease term. Lease expense is recognized within operating expenses on a straight-line basis over the terms of the lease. Incentives granted under the Company’s facilities lease, including rent holidays, are recognized as adjustments to lease expense on a straight-line basis over the term of the lease.

Short-Term Investments (Tables)

Short-Term Investments (Tables)	12 Months Ended
	Dec. 31, 2019
Investments Debt And Equity Securities [Abstract]
Schedule of short-term investments	Short-term investments consisted of available-for-sale securities as follows (in thousands): Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value December 31, 2018 Certificates of deposit $ 1,500 $ — $ — $ 1,500 December 31, 2019 Certificates of deposit $ — $ — $ — $ —

Fair Value (Tables)

Fair Value (Tables)	9 Months Ended	12 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
Schedule of Assets and Liabilities Measured at Fair Value on a Recurring Basis		The fair value hierarchy of the Company’s assets and liabilities carried at fair value and measured on a recurring basis was as follows (in thousands): As of December 31, 2018 Level 1 Level 2 Level 3 Total Assets: Short-term investments – Certificates of Deposit $ — $ 1,500 $ — $ 1,500 Total $ — $ 1,500 $ — $ 1,500 Liabilities: Grant liability — — 936 936 Derivative liability (see Note 8) — — 539 539 Total $ — $ 1,500 $ 1,475 $ 2,975 As of December 31, 2019 Level 1 Level 2 Level 3 Total Liabilities: Grant liability $ — $ — $ 1,036 $ 1,036 Derivative liability (see Note 8) — — 999 999 Total $ — $ — $ 2,035 $ 2,035
Schedule of Fair Value of Cash Equivalents, Short-term Investments and Long-term Investments	The following table reflects the Company’s financial asset balances measured on a recurring basis as of September 30, 2020 (in thousands): Level Amortized Cost Unrealized Gains Unrealized Losses Fair Value Cash equivalents: Money market fund 1 $ 66,596 — — $ 66,596 Commercial paper 2 70,392 — (3 ) 70,389 U.S. government debt and agency securities 2 835 — — 835 U.S. treasury bills 2 14,999 — — 14,999 Total cash equivalents $ 152,822 $ — $ (3 ) $ 152,819 Short-term investments: Commercial paper 2 30,393 2 (1 ) 30,394 U.S. government debt and agency securities 2 29,220 7 — 29,227 Corporate bonds 2 926 — — 926 Total short-term investments $ 60,539 $ 9 $ (1 ) $ 60,547 Long-term investments: U.S. government debt and agency securities 2 32,634 11 (9 ) 32,636 U. S. treasury bills 2 1,020 — — 1,020 Total long-term investments $ 33,654 $ 11 $ (9 ) $ 33,656
Grant Liability
Schedule of Fair Value Liabilities, Activity	The following table presents the activity for the grant liability for the year ended December 31, 2019 and nine months ended September 30, 2020 (in thousands): Year Ended December 31, 2019 Nine Months Ended September 30, 2020 Fair value at beginning of period $ 936 $ 1,036 Change in fair value of grant liability 100 464 Fair value at end of period $ 1,036 $ 1,500	The following table presents the activity for grant liability for the years ended December 31, 2018 and 2019 (in thousands): Year Ended December 31, 2018 2019 Fair value at beginning of period $ 772 $ 936 Change in fair value of grant liability 164 100 Fair value at end of period $ 936 $ 1,036
Derivative Liability
Schedule of Fair Value Liabilities, Activity	The following table presents the activity for the derivative liability for the year ended December 31, 2019 and nine months ended September 30, 2020 (in thousands): Year Ended December 31, 2019 Nine Months Ended September 30, 2020 Fair value at beginning of period $ 539 $ 999 Derivative liability recorded upon issuance of convertible notes 389 774 Change in fair value of derivative liability 71 132 Derivative liability settled upon conversion of convertible notes — (1,905 ) Fair value at end of period $ 999 $ —	The following table presents the activity for derivative liability for the years ended December 31, 2018 and 2019 (in thousands): Year Ended December 31, 2018 2019 Fair value at beginning of period $ — $ 539 Derivative liability recorded upon issuance of convertible notes 539 389 Change in fair value of derivative liability — 71 Fair value at end of period $ 539 $ 999
Convertible Preferred Stock Warrant Liability
Schedule of Fair Value Liabilities, Activity	The following table presents the activity for the convertible preferred stock warrant liability Nine Months Ended September 30, 2020 Fair value at beginning of period $ — Recognition of convertible preferred stock warrant liability 364 Change in fair value 641 Settlement upon IPO (1,005 ) Fair value at end of period $ —

Accrued Expenses (Tables)

Accrued Expenses (Tables)	9 Months Ended	12 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
Payables And Accruals [Abstract]
Schedule of Accrued Expenses	Accrued expenses consisted of the following (in thousands): As of December 31, 2019 As of September 30, 2020 Research and development expenses $ 536 $ 1,672 Employee compensation and benefits 230 229 Professional services and other 86 224 Total accrued expenses $ 852 $ 2,125	Accrued expenses consisted of the following (in thousands): As of December 31, 2018 2019 Research and development expenses $ 299 $ 536 Employee compensation and benefits 72 230 Professional services and other 80 86 Total accrued expenses $ 451 $ 852

Other Income (Expense), Net (Ta

Other Income (Expense), Net (Table)	9 Months Ended	12 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
Other Income And Expenses [Abstract]
Schedule of Other Income (Expense), Net	Other income (expense), net consisted of the following (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2019 2020 2019 2020 Part the Cloud research grant $ 189 $ — $ 472 $ 22 Interest and other income 12 35 44 45 Interest expense (98 ) — (236 ) (366 ) Change in fair value of derivative liability (77 ) — (84 ) (132 ) Change in fair value of grant liability (21 ) (453 ) (51 ) (464 ) Change in convertible preferred stock warrant liability — (641 ) — (641 ) Gain on extinguishment of convertible notes — — — 199 Total other income (expense), net $ 5 $ (1,059 ) $ 145 $ (1,337 )	Other income (expense), net consisted of the following (in thousands): Year Ended December 31, 2018 2019 Part the Cloud research grant $ — $ 754 Interest and other income 85 51 Interest expense (9 ) (346 ) Change in fair value of derivative liability — (71 ) Change in fair value of grant liability (164 ) (100 ) Total other income (expense), net $ (88 ) $ 288

Convertible Notes (Tables)

Convertible Notes (Tables)	12 Months Ended
	Dec. 31, 2019
Debt Disclosure [Abstract]
Summary of Carrying Value of Convertible Notes	The carrying value of the convertible notes as of December 31 were as follows (in thousands): As of December 31, 2018 2019 Convertible note principal and accrued interest $ 1,268 $ 2,241 Less: unamortized discount for issuance costs (14 ) (18 ) Less: unamortized discount related to derivative liability (532 ) (670 ) Net carrying value, convertible notes $ 722 $ 1,553

Convertible Preferred Stock (Ta

Convertible Preferred Stock (Tables)	9 Months Ended	12 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
Equity [Abstract]
Schedule of Convertible Preferred Stock	Convertible preferred stock as of December 31, 2019 consisted of the following (in thousands, except share amounts): Convertible Shares Issued and Aggregate Liquidation Preferred Stock Authorized Outstanding Carrying Value Preference Series A 1,714,963 1,534,885 $ 15,163 $ 15,215 Series A-1 1,082,501 1,082,501 1,888 1,073 Total 2,797,464 2,617,386 $ 17,051 $ 16,288	Convertible preferred stock as of December 31, 2018 and 2019 consisted of the following (in thousands, except share amounts): Convertible Shares Shares Issued and Carrying Value at December 31, Aggregate Liquidation Preferred Stock Authorized Outstanding 2018 2019 Preference Series A 1,714,963 1,534,885 $ 15,163 $ 15,163 $ 15,215 Series A-1 1,082,501 1,082,501 1,888 1,888 1,073 Total 2,797,464 2,617,386 $ 17,051 $ 17,051 $ 16,288

Common Stock (Tables)

Common Stock (Tables)	9 Months Ended	12 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
Equity [Abstract]
Schedule of Reserved Shares of Common Stock for Future Issuance	The Company has reserved the following shares of common stock for future issuance, on an as-converted basis, as follows: As of December 31, 2019 As of September 30, 2020 Convertible preferred stock 2,617,386 — Stock options outstanding 1,514,770 1,927,428 Shares available for future grant under the 2020 Equity Incentive Plan 399,737 3,790,279 Shares available for future grant under the Employee Stock Purchase Plan — 323,000 Common stock warrants 3,310 — Total 4,535,203 6,040,707	The Company has reserved the following shares of common stock for future issuance, on an as-converted basis, as follows: As of December 31, 2018 2019 Convertible preferred stock 2,617,386 2,617,386 Stock options outstanding 1,263,831 1,514,770 Shares available for future grant 220,675 399,737 Common stock warrants 3,310 3,310 Total 4,105,202 4,535,203

Stock-based Compensation (Table

Stock-based Compensation (Tables)	9 Months Ended	12 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock-based Compensation Expense Recognized	Stock‑based compensation expense recognized was as follows (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2019 2020 2019 2020 Research and development $ 13 $ 43 $ 42 $ 62 General and administrative 56 68 147 156 Total stock-based compensation expense $ 69 $ 111 $ 189 $ 218	Stock‑based compensation expense recognized was as follows (in thousands): Year Ended December 31, 2018 2019 Research and development $ 53 $ 55 General and administrative 143 198 Total stock-based compensation expense $ 196 $ 253
Weighted-Average Assumptions used in Estimating Fair Value of each Stock Options using Black-Scholes Option-Pricing Model	The fair value of each stock option was estimated using the Black‑Scholes option‑pricing model with the following weighted-average assumptions: Nine Months Ended September 30, 2019 2020 Risk-free interest rate 1.58 % 0.49 % Expected volatility 74.59 % 80.11 % Expected term (in years) 6.59 6.93 Expected dividend yield — —	The fair value of each stock option was estimated using the Black‑Scholes option‑pricing model with the following weighted-average assumptions: Year Ended December 31, 2018 2019 Risk-free interest rate 2.6 % 1.6 % Expected volatility 76.3 % 75.0 % Expected term (in years) 6.6 6.5 Expected dividend yield — —
Summary of Option Activity	A summary of option activity for the nine months ended September 30, 2020 was as follows: Available for Grant Shares Weighted- Average Exercise price per Share Weighted- Average Remaining Contractual Term (in years) Aggregate Intrinsic Value (in thousands) Balance at December 31, 2019 399,737 1,514,770 $ 1.03 7.16 $ 500 Authorized 4,343,534 — Granted (994,293 ) 994,293 16.20 Exercised — (540,334 ) 1.00 Forfeited/expired 41,301 (41,301 ) 1.35 Balance at September 30, 2020 3,790,279 1,927,428 $ 8.85 8.18 $ 18,521 Expected to vest 1,298,059 $ 12.71 9.52 $ 7,460 Options exercisable 629,373 $ 0.89 5.43 $ 11,061	A summary of option activity was as follows: Available for Grant Shares Weighted- Average Exercise Price Per Share Weighted- Average Remaining Contractual Term (in years) Aggregate Intrinsic Value (in thousands) Balance at December 31, 2018 220,675 1,263,831 $ 0.93 Authorized 511,966 Granted (351,819 ) 351,819 1.35 Exercised (81,965 ) 0.89 Forfeited/expired 18,915 (18,915 ) 1.35 Balance at December 31, 2019 399,737 1,514,770 $ 1.03 7.16 $ 500 Expected to vest 593,093 $ 1.35 8.79 $ 18 Options exercisable 921,677 $ 0.83 6.11 $ 477
Summary of Stock Options Outstanding and Exercisable	Stock options outstanding and exercisable consisted of the following at September 30, 2020: Employees and Directors Non-employees Exercise Price ($) Shares Outstanding Shares Exercisable Shares Outstanding Shares Exercisable 0.16 75,660 75,660 12,611 12,611 0.48 162,353 162,353 — — 1.00 — — 37,830 37,830 1.04 70,933 70,933 31,525 31,525 1.19 52,645 38,878 34,677 34,677 1.31 63,050 63,050 — — 1.35 294,754 27,529 116,642 63,049 1.49 31,525 10,508 — — 17.00 747,770 770 195,453 — Total 1,498,690 449,681 428,738 179,692	Stock options outstanding and exercisable consisted of the following at December 31, 2019: Employees and Directors Non-employees Exercise Price ($) Share Options Outstanding Share Options Exercisable Share Options Outstanding Share Options Exercisable 0.16 75,660 75,660 15,762 15,762 0.48 288,453 288,453 — — 1.00 — — 37,830 37,830 1.04 241,164 194,139 81,965 81,964 1.19 66,517 47,392 34,677 34,677 1.31 63,050 63,050 — — 1.35 414,237 22,067 163,930 60,684 1.49 31,525 — — — Total 1,180,606 690,760 334,164 230,917
Summary of RSA Activity	A summary of RSA activity for the nine months ended September 30, 2020 was Share Equivalent Weighted- Average Grant Date Fair Value Non-vested at December 31, 2019 8,407 1.35 Granted — — Vested (4,203 ) 1.35 Non-vested at September 30, 2020 4,204 $ 1.35	A summary of RSA activity was as follows: Share Equivalent Weighted- Average Grant Date Fair Value Non-vested at December 31, 2018 12,610 $ 1.35 Granted — — Vested (4,203 ) 1.35 Non-vested at December 31, 2019 8,407 $ 1.35

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Schedule of Effective Income Tax Rate Reconciliation	The provision for income taxes differs from the amount expected by applying the federal statutory rates to the net loss before taxes as follows: Year Ended December 31, 2018 2019 Federal statutory income tax rate 21.0 % 21.0 % Non-deductible expenses and others 0.2 (0.6 ) Non-deductible expense related to the convertible notes and derivative liability — (1.7 ) Non-deductible expense related to the grant liability — (0.3 ) Tax credits 2.8 2.2 Change in valuation allowance (24.0 ) (20.6 ) Effective income tax rate — % — %
Components of Deferred Tax Assets	The components of the Company’s deferred tax assets were as follows (in thousands): Year Ended December 31, 2018 2019 Deferred tax assets: Net operating loss carryforwards $ 3,032 $ 3,911 Research and development tax credit carryforwards 600 716 Accrued liabilities and other 47 93 Stock-based compensation 60 82 Total deferred tax assets 3,739 4,802 Deferred tax liabilities: Prepaid expenses and other (13 ) (12 ) Total deferred tax liabilities (13 ) (12 ) Less valuation allowance (3,726 ) (4,790 ) Net deferred tax assets $ — $ —
Schedule of Unrecognized Tax Benefits	A reconciliation of the beginning and ending amount of unrecognized tax benefits were as follows (in thousands): Year Ended December 31, 2018 2019 Beginning balance $ 152 $ 200 Additions for tax positions taken in the current year 48 39 Ending balance $ 200 $ 239

Net Loss Per Share Attributab_2

Net Loss Per Share Attributable to Common Stockholders (Tables)	9 Months Ended	12 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
Earnings Per Share [Abstract]
Summary of Dilutive Securities Excluded from Computation of Diluted Net Loss Per Share Attributable to Common Stockholders	The following outstanding shares of potentially dilutive securities were excluded from the computation of the diluted net loss per share attributable to common stockholders for the periods presented because their effect would have been anti-dilutive: Nine Months Ended September 30, 2019 2020 Convertible preferred stock on an as-converted basis 2,617,386 — Unvested RSAs 8,407 4,204 Stock options to purchase common stock 1,498,377 1,927,428 Common stock warrants 3,310 — Total 4,127,480 1,931,632	The following outstanding shares of potentially dilutive securities were excluded from the computation of the diluted net loss per share attributable to common stockholders for the periods presented because their effect would have been anti-dilutive: Year Ended December 31, 2018 2019 Convertible preferred stock on an as-converted basis 2,617,386 2,617,386 Unvested RSAs 12,610 8,407 Stock options to purchase common stock 1,263,831 1,514,770 Common stock warrants 3,310 3,310 Total 3,897,137 4,143,873
Summary of Computation of the Unaudited Pro Forma Basic And Diluted Net Loss Per Share Attributable to Common Stockholders		The following table sets forth the computation of the unaudited pro forma basic and diluted net loss per share attributable to common stockholders (in thousands, except share and per share data): Year Ended December 31, 2019 (unaudited) Numerator: Net loss $ (5,161 ) Loss on remeasurement of grant liability 100 Net loss used in computing pro forma net loss per share attributable to common stockholders, basic and diluted (5,061 ) Denominator: Weighted-average shares of common stock used in computing net loss per share attributable to common stockholders 3,566,849 Pro forma adjustment to reflect conversion of convertible preferred stock 2,617,386 Pro forma adjustment to reflect net exercise of common stock warrants 2,309 Weighted-average shares of common stock used in computing pro forma net loss per share attributable to common stockholders, basic and diluted 6,186,544 Pro forma net loss per share attributable to common stockholders, basic and diluted $ (0.82 )

Other Income (Expense), Net (_2

Other Income (Expense), Net (Tables)	9 Months Ended	12 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
Other Income And Expenses [Abstract]
Schedule of Other Income (Expense), Net	Other income (expense), net consisted of the following (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2019 2020 2019 2020 Part the Cloud research grant $ 189 $ — $ 472 $ 22 Interest and other income 12 35 44 45 Interest expense (98 ) — (236 ) (366 ) Change in fair value of derivative liability (77 ) — (84 ) (132 ) Change in fair value of grant liability (21 ) (453 ) (51 ) (464 ) Change in convertible preferred stock warrant liability — (641 ) — (641 ) Gain on extinguishment of convertible notes — — — 199 Total other income (expense), net $ 5 $ (1,059 ) $ 145 $ (1,337 )	Other income (expense), net consisted of the following (in thousands): Year Ended December 31, 2018 2019 Part the Cloud research grant $ — $ 754 Interest and other income 85 51 Interest expense (9 ) (346 ) Change in fair value of derivative liability — (71 ) Change in fair value of grant liability (164 ) (100 ) Total other income (expense), net $ (88 ) $ 288

Leases (Tables)

Leases (Tables)	9 Months Ended
	Sep. 30, 2020
Leases [Abstract]
Reconciliation of Undiscounted Operating Lease Cash Flows to Operating Lease Liability Payments	The following table reconciles the Company’s undiscounted operating lease cash flows to its operating lease liability (in thousands): As of September 30, 2020 Remaining 2020 $ — 2021 234 2022 261 2023 269 2024 277 2025 and thereafter 779 Total undiscounted lease payments 1,820 Present value adjustment for minimum lease commitments (457 ) Tenant improvement allowance receivable (391 ) Net lease liability $ 972

Description of Business and F_2

Description of Business and Financial Condition - Additional Information (Details) $ / shares in Units, $ in Thousands	Sep. 22, 2020USD ($)$ / sharesshares	Sep. 16, 2020USD ($)shares	Sep. 11, 2020	Sep. 30, 2020USD ($)shares	Sep. 30, 2020USD ($)shares	Dec. 31, 2019USD ($)shares	Dec. 31, 2018USD ($)shares	Sep. 30, 2020USD ($)shares	Sep. 23, 2020shares	Jun. 30, 2020shares	Sep. 30, 2019shares	Jun. 30, 2019shares	Dec. 31, 2017shares
Description Of Business [Line Items]
Accumulated deficit				$ 33,340	$ 33,340	$ 21,087	$ 15,926	$ 33,340
Cash and cash equivalents				165,725	165,725	$ 2,056	$ 3,317	$ 165,725
Reverse stock split, description			On September 11, 2020, the Company effected a one-for-7.9302 reverse split of its issued and outstanding common stock, convertible preferred stock, warrants, and stock options.
Reverse stock split conversion ratio			0.1261
Net proceeds from public offering					187,224
Loss on final re-measurement of fair value of warrant liability				$ 641	$ 641
Temporary equity shares outstanding | shares				0	0	2,617,386	2,617,386	0
Net cash proceeds from issuance of convertible preferred stock, common stock warrants, and convertible notes								$ 288,500
Cash, cash equivalents, and investments				$ 259,900	$ 259,900			$ 259,900
Common Stock Warrants
Description Of Business [Line Items]
Common shares issued upon exercise of warrants | shares		1,085,334
Series B Convertible Preferred Stock Warrant
Description Of Business [Line Items]
Common shares issued upon exercise of warrants | shares		59,093
Series B Convertible Preferred Stock Warrant | Other Income (Expense), Net
Description Of Business [Line Items]
Loss on final re-measurement of fair value of warrant liability		$ 600
Convertible Preferred Stock, Common Stock Warrants Or Series B Convertible Preferred Stock Warrants
Description Of Business [Line Items]
Temporary equity shares outstanding | shares									0
IPO
Description Of Business [Line Items]
Issuance of convertible preferred stock for cash of $1.25 per share, shares | shares	12,000,000
Public offering price per share | $ / shares	$ 17
Net proceeds from public offering	$ 186,400
Series B Convertible Preferred Stock
Description Of Business [Line Items]
Proceeds from issuance of convertible preferred stock						$ 81,800
Convertible Preferred Stock
Description Of Business [Line Items]
Issuance of convertible preferred stock for cash of $1.25 per share, shares | shares							10,088
Temporary equity shares outstanding | shares						2,617,386	2,617,386			12,503,009	2,617,386	2,617,386	2,607,298
Convertible Preferred Stock | IPO
Description Of Business [Line Items]
Common shares issued on conversion of convertible preferred stock | shares	12,503,009

Significant Accounting Polici_3

Significant Accounting Policies - Additional Information (Details) $ in Thousands	3 Months Ended	9 Months Ended		12 Months Ended
	Sep. 30, 2019USD ($)	Sep. 30, 2020USD ($)Segment	Sep. 30, 2019USD ($)	Dec. 31, 2019USD ($)Segment	Jul. 01, 2020USD ($)	Jan. 31, 2019USD ($)	Dec. 31, 2018USD ($)
Basis Of Presentation And Significant Accounting Policies [Line Items]
Grant liability		$ 1,500
Grant income recognized	$ 189	22	$ 472	$ 754
Proceeds from initial public offering, net of issuance costs		$ 187,224
Number of operating segments | Segment		1		1
Unsecured related party note receivable				$ 36,000			$ 42,000
Lease, practical expedient, use of hindsight		true
Operating lease right-of-use asset		$ 959
Operating lease liabilities		$ 972
ASU 2016-02
Basis Of Presentation And Significant Accounting Policies [Line Items]
Change in accounting principle, accounting standards update, adopted		true
Change in accounting principle, accounting standards update, adoption date		Jan. 1, 2020
Operating lease right-of-use asset					$ 1,000
Operating lease liabilities					$ 1,000
ASU 2018-07
Basis Of Presentation And Significant Accounting Policies [Line Items]
Change in accounting principle, accounting standards update, adopted		true
Change in accounting principle, accounting standards update, adoption date		Jan. 1, 2020
Change in accounting principle, accounting standards update, material impact		true
ASU 2018-13
Basis Of Presentation And Significant Accounting Policies [Line Items]
Change in accounting principle, accounting standards update, adopted		true
Change in accounting principle, accounting standards update, adoption date		Jan. 1, 2020
Change in accounting principle, accounting standards update, material impact		true
Unsecured Related Party Note Receivable
Basis Of Presentation And Significant Accounting Policies [Line Items]
Debt instrument, interest rate				1.45%
Debt instrument, maturity month and year				2025-04
Alzheimers Association
Basis Of Presentation And Significant Accounting Policies [Line Items]
Research grant awarded						$ 1,000
Grant received				$ 776,000
Remaining grant to be received				224,000
Alzheimers Association | Accrued Expenses
Basis Of Presentation And Significant Accounting Policies [Line Items]
Cash received in excess of expenses				22,000
Alzheimers Association | Other Income (Expense), Net
Basis Of Presentation And Significant Accounting Policies [Line Items]
Grant income recognized				754,000
Maximum
Basis Of Presentation And Significant Accounting Policies [Line Items]
Grant liability				1,500
Minimum
Basis Of Presentation And Significant Accounting Policies [Line Items]
Proceeds from initial public offering, net of issuance costs				$ 50,000

Short-Term Investments - Schedu

Short-Term Investments - Schedule of Short-Term Investments (Details) - Certificates of Deposit - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	$ 0	$ 1,500
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Fair Value	$ 0	$ 1,500

Short-Term Investments - Additi

Short-Term Investments - Additional Information (Details)	12 Months Ended
	Dec. 31, 2019
Maximum
Schedule Of Available For Sale Securities [Line Items]
Contractual maturity	1 year

Fair Value - Schedule of Assets

Fair Value - Schedule of Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) - Recurring Basis - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Assets		$ 1,500
Liabilities	$ 2,035	2,975
Short-term Investments | Certificates of Deposit
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Assets		1,500
Grant Liability
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Liabilities	1,036	936
Derivative Liability
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Liabilities	999	539
Level 2
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Assets		1,500
Liabilities		1,500
Level 2 | Short-term Investments | Certificates of Deposit
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Assets		1,500
Level 3
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Liabilities	2,035	1,475
Level 3 | Grant Liability
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Liabilities	1,036	936
Level 3 | Derivative Liability
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Liabilities	$ 999	$ 539

Fair Value - Schedule of Fair V

Fair Value - Schedule of Fair Value Liabilities, Activity for Grant Liability (Details) - Grant Liability - USD ($)	9 Months Ended	12 Months Ended
	Sep. 30, 2020	Dec. 31, 2019	Dec. 31, 2018
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Fair value at beginning of period	$ 1,036,000	$ 936,000	$ 772,000
Change in fair value of liability	464,000	100,000	164,000
Fair value at end of period	$ 1,500,000	$ 1,036,000	$ 936,000

Fair Value - Schedule of Fair_2

Fair Value - Schedule of Fair Value Liabilities, Activity for Derivative Liability (Details) - Derivative Liability - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2020	Dec. 31, 2019	Dec. 31, 2018
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Fair value at beginning of period	$ 999	$ 539
Derivative liability recorded upon issuance of convertible notes	774	389	$ 539
Change in fair value of liability	132	71
Settlement	$ (1,905)
Fair value at end of period		$ 999	$ 539

Accrued Expenses - Schedule of

Accrued Expenses - Schedule of Accrued Expenses (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019	Dec. 31, 2018
Payables And Accruals [Abstract]
Research and development expenses	$ 1,672	$ 536	$ 299
Employee compensation and benefits	229	230	72
Professional services and other	224	86	80
Total accrued expenses	$ 2,125	$ 852	$ 451

Other Income (Expense), Net - S

Other Income (Expense), Net - Schedule of Other Income (Expense), Net (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019	Dec. 31, 2018
Other Income And Expenses [Abstract]
Part the Cloud research grant		$ 189	$ 22	$ 472	$ 754
Interest and other income	$ 35	12	45	44	51	$ 85
Interest expense		(98)	(366)	(236)	(346)	(9)
Change in fair value of derivative liability		(77)	(132)	(84)	(71)
Change in fair value of grant liability	(453)	(21)	(464)	(51)	(100)	(164)
Change in convertible preferred stockwarrant liability	(641)		(641)
Gain on extinguishment of convertiblenotes			199
Total other income (expense), net	$ (1,059)	$ 5	$ (1,337)	$ 145	$ 288	$ (88)

Significant Agreements - Additi

Significant Agreements - Additional Information (Details) - USD ($)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2015	Dec. 31, 2014
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Change in fair value of grant liability	$ 453,000	$ 21,000	$ 464,000	$ 51,000	$ 100,000	$ 164,000
Washington State University License Agreement
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Milestone payments payable upon marketing approval							$ 600,000
Annual minimum royalty payments							25,000
Net sales exempt from royalty payment							100,000
Royalty obligation	0		0		0
Washington State University License Agreement | Phase 2 Clinical Trial Initiation
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Milestone payments, amount payable							50,000
Milestone payments on development milestone achieved			50,000
Washington State University License Agreement | Phase 3 Clinical Trial Initiation
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Milestone payments, amount payable							300,000
Washington Life Services Discovery Fund Grant Agreement
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Grant received							500,000	$ 250,000
Grant liability payable amount, maximum							$ 1,500,000
Estimated fair value of the grant liability	1,500,000		1,500,000		1,000,000	936,000
Washington Life Services Discovery Fund Grant Agreement | Other Income (Expense), Net
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Change in fair value of grant liability	$ 453,000	$ 21,000	$ 464,000	$ 51,000	$ 100,000	$ 164,000

Debt - Additional Information (

Debt - Additional Information (Details) - USD ($)	1 Months Ended		9 Months Ended	12 Months Ended
	May 31, 2020	Apr. 30, 2020	Sep. 30, 2020	Dec. 31, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Gain on extinguishment of debt			$ 199,000
Paycheck Protection Program
Debt Instrument [Line Items]
Debt instrument, interest rate		1.00%
Loan amount received		$ 215,000
Loan repayment term		2 years
Unsecured Convertible Notes
Debt Instrument [Line Items]
Debt instrument, principal amount			$ 1,700,000	$ 884,000	$ 1,300,000
Debt instrument, interest rate			5.00%	5.00%
Debt instrument, maturity month and year			2021-12	2021-12
Debt instrument, payment terms			No principal or interest is payable prior to maturity as the convertible notes and any accrued interest will automatically convert upon a qualified financing event at a conversion price equal to 85% of the price per share of the qualified financing.	No principal or interest is payable prior to maturity as the convertible notes and any accrued interest will automatically convert upon a qualified financing event at a conversion price equal to 85% of the price per share of the qualified financing
Debt instrument, conversion price, percentage			85.00%	85.00%
Debt instrument, repurchase price, percentage			200.00%	200.00%
Debt conversion, converted instrument, amount	$ 3,800,000
Debt instrument, accrued interest	160,000
Gain on extinguishment of debt	199,000
Unsecured Convertible Notes | Previously Reported
Debt Instrument [Line Items]
Debt conversion, converted instrument, amount	2,200,000
Debt instrument, accrued interest	$ 131,000
Unsecured Convertible Notes | Series B-1 Convertible Preferred Stock
Debt Instrument [Line Items]
Debt conversion, converted instrument, shares issued	512,858
Unsecured Convertible Notes | Series B-1 Convertible Preferred Stock | Previously Reported
Debt Instrument [Line Items]
Debt conversion, converted instrument, shares issued	294,197

Convertible Notes- Summary of C

Convertible Notes- Summary of Carrying Value of Convertible Notes (Details) - Unsecured Convertible Notes - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Convertible note principal and accrued interest	$ 2,241	$ 1,268
Less: unamortized discount for issuance costs	(18)	(14)
Less: unamortized discount related to derivative liability	(670)	(532)
Net carrying value, convertible notes	$ 1,553	$ 722

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Operating Leased Assets [Line Items]
Rent expense	$ 97,000	$ 82,000
Laboratory and Office Facilities
Operating Leased Assets [Line Items]
Operating Lease, term of contract	1 year	1 year

Convertible Preferred Stock - S

Convertible Preferred Stock - Schedule of Convertible Preferred Stock (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019	Dec. 31, 2018
Class Of Stock [Line Items]
Convertible Preferred Stock, Shares Authorized	0	2,797,464	2,797,464
Convertible Preferred Stock, Shares Issued	0	2,617,386	2,617,386
Convertible Preferred Stock, Shares Outstanding	0	2,617,386	2,617,386
Convertible Preferred Stock, Carrying Value		$ 17,051	$ 17,051
Convertible Preferred Stock, Aggregate Liquidation Preference		$ 16,288	$ 16,288
Series A Convertible Preferred Stock
Class Of Stock [Line Items]
Convertible Preferred Stock, Shares Authorized		1,714,963	1,714,963
Convertible Preferred Stock, Shares Issued		1,534,885	1,534,885
Convertible Preferred Stock, Shares Outstanding		1,534,885	1,534,885
Convertible Preferred Stock, Carrying Value		$ 15,163	$ 15,163
Convertible Preferred Stock, Aggregate Liquidation Preference		$ 15,215	$ 15,215
Series A-1 Convertible Preferred Stock
Class Of Stock [Line Items]
Convertible Preferred Stock, Shares Authorized		1,082,501	1,082,501
Convertible Preferred Stock, Shares Issued		1,082,501	1,082,501
Convertible Preferred Stock, Shares Outstanding		1,082,501	1,082,501
Convertible Preferred Stock, Carrying Value		$ 1,888	$ 1,888
Convertible Preferred Stock, Aggregate Liquidation Preference		$ 1,073	$ 1,073

Convertible Preferred Stock - A

Convertible Preferred Stock - Additional Information (Details) - USD ($)	Sep. 22, 2020	Jun. 30, 2020	Sep. 30, 2020	Dec. 31, 2019	Dec. 31, 2018
Class Of Stock [Line Items]
Convertible preferred stock terms of conversion		The Series B convertible preferred stock financing triggered the automatic conversion of the Company’s outstanding convertible promissory notes into 512,858 shares of Series B-1 convertible preferred stock based on a price of $7.752 per share (85% of the $9.12 original issuance price of the Series B convertible preferred stock).		Preferred Stock will automatically convert into shares of common stock on a 1:1 basis upon the earlier to occur: (a) after the payment of the distribution preference to the holders of the Series A and Series A-1 Preferred Stock, and (b) upon the closing of a firmly underwritten public offering pursuant to an effective registration statement covering the offer and sale of common stock in which the gross proceeds to the Company are at least $50.0 million.
Proceeds from initial public offering, net of issuance costs			$ 187,224,000
Initial conversion rate, preferred stock into common stock				The initial conversion rate shall be 1:1, subject to any adjustments for stock splits, combinations, common stock dividends and distributions, reclassifications, exchanges, substitutions, reorganizations, mergers or consolidations.
Shares issued			0	2,617,386	2,617,386
IPO
Class Of Stock [Line Items]
Proceeds from initial public offering, net of issuance costs	$ 186,400,000
Common Stock | IPO
Class Of Stock [Line Items]
Convertible preferred stock shares issued upon conversion			12,503,009
Minimum
Class Of Stock [Line Items]
Proceeds from initial public offering, net of issuance costs				$ 50,000,000
Preferred Stock
Class Of Stock [Line Items]
Dividend payment restrictions schedule, description				The holders of shares of Series A and Series A-1 Preferred Stock are entitled to receive non-cumulative dividends and non-dividend distributions in preference to any dividend or non-dividend distribution on the common stock, when, and if declared by the Company’s board of directors. Such dividend and non-dividend distribution preference survives until the holders of the Series A Preferred Stock and Series A-1 Preferred Stock have received a per share amount equal to: (a) in the case of dividends, 1.32 times the Series A Purchase Price or Series A-1 Purchase Price, as applicable, or (b) in the case of non-dividend distributions, the Series A Purchase Price or Series A-1 Purchase Price, as applicable.
Series A-1 Convertible Preferred Stock
Class Of Stock [Line Items]
beneficial conversion feature recorded upon issuance of the underlying shares				$ 815,000
Preferred Stock, Voting Rights				one
Shares issued				1,082,501	1,082,501
Series A Convertible Preferred Stock
Class Of Stock [Line Items]
Preferred Stock, Voting Rights				one
Shares issued				1,534,885	1,534,885
Series B Convertible Preferred Stock
Class Of Stock [Line Items]
Shares issued		9,372,765
Purchase price per share		$ 9.12
Proceeds from issuance of convertible preferred stock		$ 81,600,000
Warrants to purchase preferred stock		2,343,168
Warrants to purchase preferred stock exercised		688,067
Convertible preferred stock issuance for net proceeds		$ 55,000
Series B Convertible Preferred Stock | Purchase Price $1.15 Per Share
Class Of Stock [Line Items]
Warrants to purchase preferred stock		127,481
Exercise price		$ 9.12
Series B-1 Convertible Preferred Stock
Class Of Stock [Line Items]
Exercise price		$ 9.12
Convertible preferred stock shares issued upon conversion		512,858
Convertible preferred stock conversion price		$ 7.752
Convertible preferred stock conversion price percentage		85.00%

Common Stock - Schedule of Rese

Common Stock - Schedule of Reserved Shares of Common Stock for Future Issuance (Details) - shares	Sep. 30, 2020	Dec. 31, 2019	Dec. 31, 2018
Class Of Stock [Line Items]
Reserved shares of common stock for future issuance	6,040,707	4,535,203	4,105,202
Convertible Preferred Stock
Class Of Stock [Line Items]
Reserved shares of common stock for future issuance		2,617,386	2,617,386
Stock Options Outstanding
Class Of Stock [Line Items]
Reserved shares of common stock for future issuance	1,927,428	1,514,770	1,263,831
Shares Available For Future Grant
Class Of Stock [Line Items]
Reserved shares of common stock for future issuance		399,737	220,675
Shares available for Future Grant under 2020 Equity Incentive Plan
Class Of Stock [Line Items]
Reserved shares of common stock for future issuance	3,790,279	399,737
Shares available for Future Grant under Employee Stock Purchase Plan
Class Of Stock [Line Items]
Reserved shares of common stock for future issuance	323,000
Common Stock Warrants
Class Of Stock [Line Items]
Reserved shares of common stock for future issuance		3,310	3,310

Common Stock - Additional Infor

Common Stock - Additional Information (Details) - Common Stock Warrants	12 Months Ended
	Dec. 31, 2019$ / shares
Class Of Stock [Line Items]
Exercise price	$ 7.93
Expiration date	Apr. 8, 2021

Stock-based Compensation - Addi

Stock-based Compensation - Additional Information (Details) - USD ($)	9 Months Ended		12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019	Dec. 31, 2018
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Reserved shares of common stock for future issuance	6,040,707		4,535,203	4,105,202
Contractual term			10 years
Option agreement option term			5 years
Vesting period			4 years
Expected dividend yield	0.00%		0.00%
Fair value of options vested	$ 219,000	$ 123,000	$ 183,000	$ 160,000
Aggregate intrinsic value of options exercised	9,400,000	4,000	38,500	297,000
Unrecognized compensation cost	$ 2,900,000		$ 374,000
Remaining weighted-average period expected to recognize unrecognized compensation cost	1 year 11 months 12 days		1 year 4 months 28 days
Restricted Stock Award (RSA)
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting period	3 years		3 years
Unrecognized compensation cost			$ 6,000
Remaining weighted-average period expected to recognize unrecognized compensation cost			1 year 2 months 23 days
Employees and Directors
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Weighted-average grant-date fair value of options granted	$ 2,100,000	259,000	$ 890	790
Fair value of options vested	144,000	64,000	104,000	115,000
Advisors
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Weighted-average grant-date fair value of options granted	727,000	46,000	1,060	1,080
Fair value of options vested	$ 75,000	$ 59,000	$ 79,000	$ 45,000
Non-employees | Restricted Stock Award (RSA)
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares subject to repurchase upon discontinued service	4,204		8,407
Cliff Vesting
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Option vesting percentage			100.00%
Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Exercise price, percentage of fair market value			110.00%
Equity Incentive 2014 Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Reserved shares of common stock for future issuance			3,076,214

Stock-based Compensation - Stoc

Stock-based Compensation - Stock-based Compensation Expense Recognized (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019	Dec. 31, 2018
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 111	$ 69	$ 218	$ 189	$ 253	$ 196
Research and Development
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	43	13	62	42	55	53
General and Administrative
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 68	$ 56	$ 156	$ 147	$ 198	$ 143

Stock-based Compensation - Weig

Stock-based Compensation - Weighted-Average Assumptions used in Estimating Fair Value of each Stock Options using Black-Scholes Option-Pricing Model (Details)	9 Months Ended		12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019	Dec. 31, 2018
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Risk-free interest rate	0.49%	1.58%	1.60%	2.60%
Expected volatility	80.11%	74.59%	75.00%	76.30%
Expected term (in years)	6 years 11 months 4 days	6 years 7 months 2 days	6 years 6 months	6 years 7 months 6 days
Expected dividend yield	0.00%		0.00%

Stock-based Compensation - Summ

Stock-based Compensation - Summary of Option Activity (Details) $ / shares in Units, $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2020USD ($)$ / sharesshares	Dec. 31, 2019USD ($)$ / sharesshares
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Available for Grant, Beginning Balance	399,737	220,675
Available for Grant, Authorized	4,343,534	511,966
Available for Grant, Granted	(994,293)	(351,819)
Available for Grant, Forfeited/expired	41,301	18,915
Available for Grant, Ending Balance	3,790,279	399,737
Shares, Beginning Balance	1,514,770	1,263,831
Shares, Granted	994,293	351,819
Shares, Exercised	(540,334)	(81,965)
Shares, Forfeited/expired	(41,301)	(18,915)
Shares, Ending Balance	1,927,428	1,514,770
Shares, Expected to vest	1,298,059	593,093
Shares, Options exercisable	629,373	921,677
Weighted-Average Exercise price per Share, Beginning Balance | $ / shares	$ 1.03	$ 0.93
Weighted-Average Exercise price per Share, Granted | $ / shares	16.20	1.35
Weighted-Average Exercise price per Share, Exercised | $ / shares	1	0.89
Weighted-Average Exercise price per Share, Forfeited/expired | $ / shares	1.35	1.35
Weighted-Average Exercise price per Share, Ending Balance | $ / shares	8.85	1.03
Weighted-Average Exercise price per Share, Expected to vest | $ / shares	12.71	1.35
Weighted-Average Exercise price per Share, Options exercisable | $ / shares	$ 0.89	$ 0.83
Weighted-Average Remaining Contractual Term (in years)	8 years 2 months 4 days	7 years 1 month 28 days
Weighted-Average Remaining Contractual Term, Expected to vest (in years)	9 years 6 months 7 days	8 years 9 months 14 days
Weighted-Average Remaining Contractual Term, Options exercisable (in years)	5 years 5 months 4 days	6 years 1 month 9 days
Aggregate Intrinsic Value | $	$ 18,521	$ 500
Aggregate Intrinsic Value, Expected to vest | $	7,460	18
Aggregate Intrinsic Value, Options exercisable | $	$ 11,061	$ 477

Stock-based Compensation - Su_2

Stock-based Compensation - Summary of Stock Options Outstanding and Exercisable (Details) - $ / shares	9 Months Ended	12 Months Ended
	Sep. 30, 2020	Dec. 31, 2019	Dec. 31, 2018
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Shares Outstanding	1,927,428	1,514,770	1,263,831
Shares Exercisable	629,373	921,677
Employees and Directors
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Shares Outstanding	1,498,690	1,180,606
Shares Exercisable	449,681	690,760
Non-employees
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Shares Outstanding	428,738	334,164
Shares Exercisable	179,692	230,917
Exercise Price $0.16
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Exercise Price ($)	$ 0.16	$ 0.16
Exercise Price $0.16 | Employees and Directors
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Shares Outstanding	75,660	75,660
Shares Exercisable	75,660	75,660
Exercise Price $0.16 | Non-employees
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Shares Outstanding	12,611	15,762
Shares Exercisable	12,611	15,762
Exercise Price $0.48
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Exercise Price ($)	$ 0.48	$ 0.48
Exercise Price $0.48 | Employees and Directors
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Shares Outstanding	162,353	288,453
Shares Exercisable	162,353	288,453
Exercise Price $1.00
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Exercise Price ($)	$ 1	$ 1
Exercise Price $1.00 | Non-employees
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Shares Outstanding	37,830	37,830
Shares Exercisable	37,830	37,830
Exercise Price $1.04
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Exercise Price ($)	$ 1.04	$ 1.04
Exercise Price $1.04 | Employees and Directors
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Shares Outstanding	70,933	241,164
Shares Exercisable	70,933	194,139
Exercise Price $1.04 | Non-employees
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Shares Outstanding	31,525	81,965
Shares Exercisable	31,525	81,964
Exercise Price $1.19
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Exercise Price ($)	$ 1.19	$ 1.19
Exercise Price $1.19 | Employees and Directors
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Shares Outstanding	52,645	66,517
Shares Exercisable	38,878	47,392
Exercise Price $1.19 | Non-employees
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Shares Outstanding	34,677	34,677
Shares Exercisable	34,677	34,677
Exercise Price $1.31
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Exercise Price ($)	$ 1.31	$ 1.31
Exercise Price $1.31 | Employees and Directors
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Shares Outstanding	63,050	63,050
Shares Exercisable	63,050	63,050
Exercise Price $1.35
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Exercise Price ($)	$ 1.35	$ 1.35
Exercise Price $1.35 | Employees and Directors
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Shares Outstanding	294,754	414,237
Shares Exercisable	27,529	22,067
Exercise Price $1.35 | Non-employees
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Shares Outstanding	116,642	163,930
Shares Exercisable	63,049	60,684
Exercise Price $1.49
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Exercise Price ($)	$ 1.49	$ 1.49
Exercise Price $1.49 | Employees and Directors
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Shares Outstanding	31,525	31,525
Shares Exercisable	10,508
Exercise Price $17.00
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Exercise Price ($)	$ 17
Exercise Price $17.00 | Employees and Directors
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Shares Outstanding	747,770
Shares Exercisable	770
Exercise Price $17.00 | Non-employees
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Shares Outstanding	195,453

Stock-based Compensation - Su_3

Stock-based Compensation - Summary of RSA Activity (Details) - Restricted Stock Award (RSA) - $ / shares	9 Months Ended	12 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share Equivalent, Non-vested, Beginning Balance	8,407	12,610
Share Equivalent, Vested	(4,203)	(4,203)
Share Equivalent, Non-vested, Ending Balance	4,204	8,407
Weighted-Average Grant Date Fair Value, Non-vested, Beginning Balance	$ 1.35	$ 1.35
Weighted-Average Grant Date Fair Value, Non-vested, Vested	1.35	1.35
Weighted-Average Grant Date Fair Value, Non-vested, Ending Balance	$ 1.35	$ 1.35

Income Taxes - Schedule of Effe

Income Taxes - Schedule of Effective Income Tax Rate Reconciliation (Details)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Federal statutory income tax rate	21.00%	21.00%
Non-deductible expenses and others	(0.60%)	0.20%
Non-deductible expense related to the convertible notes and derivative liability	(1.70%)	0.00%
Non-deductible expense related to the grant liability	(0.30%)	0.00%
Tax credits	2.20%	2.80%
Change in valuation allowance	(20.60%)	(24.00%)
Effective income tax rate	0.00%	0.00%

Income Taxes - Components of De

Income Taxes - Components of Deferred Tax Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Deferred tax assets:
Net operating loss carryforwards	$ 3,911	$ 3,032
Research and development tax credit carryforwards	716	600
Accrued liabilities and other	93	47
Stock-based compensation	82	60
Total deferred tax assets	4,802	3,739
Deferred tax liabilities:
Prepaid expenses and other	(12)	(13)
Total deferred tax liabilities	(12)	(13)
Less valuation allowance	(4,790)	(3,726)
Net deferred tax assets	$ 0	$ 0

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Income Tax Contingency [Line Items]
Change in valuation allowance	$ 1.1	$ 1.2
Federal
Income Tax Contingency [Line Items]
Net operating loss carryforwards	9.4	$ 9.2
Tax credit carryforwards	$ 1
Federal | Minimum
Income Tax Contingency [Line Items]
Net operating loss and tax credit carryforwards, expiration period	11 years
Federal | Maximum
Income Tax Contingency [Line Items]
Net operating loss and tax credit carryforwards, expiration period	20 years

Income Taxes - Schedule of Unre

Income Taxes - Schedule of Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Beginning balance	$ 200	$ 152
Additions for tax positions taken in the current year	39	48
Ending balance	$ 239	$ 200

Employee Benefit Plans (Details

Employee Benefit Plans (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Employee Benefit Plans [Abstract]
Percentage of pretax compensation eligible to defer	100.00%
Matching contributions	$ 0	$ 0

Net Loss Per Share Attributab_3

Net Loss Per Share Attributable to Common Stockholders - Summary of Dilutive Securities excluded from Computation of Diluted Net Loss Per Share Attributable to Common Stockholders (Details) - shares	9 Months Ended		12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019	Dec. 31, 2018
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Outstanding shares of potentially dilutive securities were excluded from the computation of the diluted net loss per share	1,931,632	4,127,480	4,143,873	3,897,137
Convertible Preferred Stock on An as-converted Basis
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Outstanding shares of potentially dilutive securities were excluded from the computation of the diluted net loss per share		2,617,386	2,617,386	2,617,386
Unvested RSAs
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Outstanding shares of potentially dilutive securities were excluded from the computation of the diluted net loss per share	4,204	8,407	8,407	12,610
Stock Options to Purchase Common Stock
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Outstanding shares of potentially dilutive securities were excluded from the computation of the diluted net loss per share	1,927,428	1,498,377	1,514,770	1,263,831
Common Stock Warrants
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Outstanding shares of potentially dilutive securities were excluded from the computation of the diluted net loss per share		3,310	3,310	3,310

Unaudited Pro Forma Net Loss Pe

Unaudited Pro Forma Net Loss Per Share Attributable to Common Stockholders - Summary of Computation of the Unaudited Pro Forma Basic And Diluted Net Loss Per Share Attributable to Common Stockholders (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019	Dec. 31, 2018
Earnings Per Share [Abstract]
Net loss	$ (8,456)	$ (1,530)	$ (12,253)	$ (4,187)	$ (5,161)	$ (5,097)
Loss on remeasurement of grant liability					100
Net loss used in computing pro forma net loss per share attributable to common stockholders, basic and diluted					$ (5,061)
Weighted-average shares used in computing net loss per share attributable to common stockholders, basic and diluted	7,564,538	3,554,345	5,155,338	3,551,586	3,566,849	3,469,153
Pro forma adjustment to reflect conversion of convertible preferred stock					2,617,386
Pro forma adjustment to reflect net exercise of common stock warrants					2,309
Weighted-average shares of common stock used in computing pro forma net loss per share attributable to common stockholders, basic and diluted					6,186,544
Pro forma net loss per share attributable to common stockholders, basic and diluted					$ (0.82)

Subsequent Events - Additional

Subsequent Events - Additional Information (Details)	Oct. 16, 2020USD ($)$ / sharesshares	Sep. 11, 2020	Sep. 30, 2020USD ($)shares	Apr. 30, 2020USD ($)	Jan. 31, 2020USD ($)$ / sharesshares	Jun. 30, 2020USD ($)$ / sharesshares	Sep. 30, 2020USD ($)$ / sharesshares	Sep. 30, 2019USD ($)	Dec. 31, 2019USD ($)$ / sharesshares	Dec. 31, 2018USD ($)shares
Subsequent Event [Line Items]
Shares, Granted							994,293		351,819
Weighted-Average Exercise price per Share, Granted | $ / shares							$ 16.20		$ 1.35
Reserved shares of common stock for future issuance			6,040,707				6,040,707		4,535,203	4,105,202
Proceeds from issuance of convertible notes, including derivative | $							$ 1,666,000	$ 884,000	$ 884,000	$ 1,266,000
Convertible preferred stock, shares issued			0				0		2,617,386	2,617,386
Reverse stock split, description		On September 11, 2020, the Company effected a one-for-7.9302 reverse split of its issued and outstanding common stock, convertible preferred stock, warrants, and stock options.
Reverse stock split conversion ratio		0.1261
Proceeds from initial public offering, net of issuance costs | $							$ 187,224,000
Shares available for Future Grant under Employee Stock Purchase Plan
Subsequent Event [Line Items]
Reserved shares of common stock for future issuance			323,000				323,000
Series B Convertible Preferred Stock
Subsequent Event [Line Items]
Convertible preferred stock, shares issued						9,372,765
Purchase price per share | $ / shares						$ 9.12
Proceeds from issuance of convertible preferred stock | $						$ 81,600,000
Warrants to purchase preferred stock						2,343,168
Warrants to purchase preferred stock exercised						688,067
Convertible preferred stock issuance for net proceeds | $						$ 55,000
Series B-1 Convertible Preferred Stock
Subsequent Event [Line Items]
Exercise price | $ / shares						$ 9.12
Convertible preferred stock shares issued upon conversion						512,858
Convertible preferred stock conversion price | $ / shares						$ 7.752
Convertible preferred stock conversion price percentage						85.00%
Paycheck Protection Program
Subsequent Event [Line Items]
Loan amount received | $				$ 215,000
Debt instrument, interest rate				1.00%
Loan repayment term				2 years
Forecast
Subsequent Event [Line Items]
Reserved shares of common stock for future issuance			943,223				943,223
Reverse stock split, description		In September 2020, the board of directors of the Company approved an amendment to the Company’s certificate of incorporation to effect a reverse split of shares of the Company’s common stock and preferred stock on a 7.9302-for-one basis, which was effected on September 11, 2020.
Reverse stock split conversion ratio		0.1261
Forecast | Grant
Subsequent Event [Line Items]
Revenue | $			$ 7,800,000
Forecast | Shares available for Future Grant under Employee Stock Purchase Plan
Subsequent Event [Line Items]
Reserved shares of common stock for future issuance			323,000				323,000
Forecast | Series B Convertible Preferred Stock
Subsequent Event [Line Items]
Convertible preferred stock, shares issued						9,372,765
Purchase price per share | $ / shares						$ 9.12
Proceeds from issuance of convertible preferred stock | $						$ 81,800,000
Warrants to purchase preferred stock						2,343,168
Warrants to purchase preferred stock exercised						688,067
Convertible preferred stock issuance for net proceeds | $						$ 55,000
Forecast | Series B Convertible Preferred Stock | Series B Convertible Preferred Stock Warrants
Subsequent Event [Line Items]
Warrants to purchase preferred stock						127,481
Exercise price | $ / shares						$ 9.12
Forecast | Series B-1 Convertible Preferred Stock
Subsequent Event [Line Items]
Exercise price | $ / shares						$ 9.12
Convertible preferred stock shares issued upon conversion						512,858
Convertible preferred stock conversion price | $ / shares						$ 7.752
Convertible preferred stock conversion price percentage						85.00%
Forecast | Paycheck Protection Program
Subsequent Event [Line Items]
Loan amount received | $				$ 215,000
Debt instrument, interest rate				1.00%
Loan repayment term				2 years
Subsequent Event
Subsequent Event [Line Items]
Shares, Granted					44,765
Weighted-Average Exercise price per Share, Granted | $ / shares					$ 1.35
Proceeds from issuance of convertible notes, including derivative | $					$ 1,700,000
Subsequent Event | Underwriters’ Option
Subsequent Event [Line Items]
Issuance of convertible preferred stock for cash of $1.25 per share, shares	1,397,712
Public offering price per share | $ / shares	$ 17
Proceeds from initial public offering, net of issuance costs | $	$ 22,100,000
Subsequent Event | Chief Operating Officer and Affiliates
Subsequent Event [Line Items]
Proceeds from issuance of convertible notes, including derivative | $					$ 250,000

Fair Value - Schedule of Fair_3

Fair Value - Schedule of Fair Value of Cash Equivalents, Short-term Investments and Long-term Investments (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019	Dec. 31, 2018
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Cash equivalents, Amortized Cost	$ 165,725	$ 2,056	$ 3,317
Recurring Basis | Cash Equivalents
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Cash equivalents, Amortized Cost	152,822
Cash equivalents, Unrealized Losses	(3)
Cash equivalents, Fair Value	152,819
Recurring Basis | Cash Equivalents | Money Market Fund | Level 1
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Cash equivalents, Amortized Cost	66,596
Cash equivalents, Fair Value	66,596
Recurring Basis | Cash Equivalents | Commercial Paper | Level 2
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Cash equivalents, Amortized Cost	70,392
Cash equivalents, Unrealized Losses	(3)
Cash equivalents, Fair Value	70,389
Recurring Basis | Cash Equivalents | U.S. Government Debt and Agency Securities | Level 2
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Cash equivalents, Amortized Cost	835
Cash equivalents, Fair Value	835
Recurring Basis | Cash Equivalents | U.S. Treasury Bills | Level 2
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Cash equivalents, Amortized Cost	14,999
Cash equivalents, Fair Value	14,999
Recurring Basis | Short-term Investments
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Investments, Amortized Cost	60,539
Investments, Unrealized Gains	9
Investments, Unrealized Losses	(1)
Fair Value	60,547
Recurring Basis | Short-term Investments | Commercial Paper | Level 2
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Investments, Amortized Cost	30,393
Investments, Unrealized Gains	2
Investments, Unrealized Losses	(1)
Fair Value	30,394
Recurring Basis | Short-term Investments | U.S. Government Debt and Agency Securities | Level 2
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Investments, Amortized Cost	29,220
Investments, Unrealized Gains	7
Fair Value	29,227
Recurring Basis | Short-term Investments | Corporate Bond Securities | Level 2
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Investments, Amortized Cost	926
Fair Value	926
Recurring Basis | Long Term Investments
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Investments, Amortized Cost	33,654
Investments, Unrealized Gains	11
Investments, Unrealized Losses	(9)
Investments, Fair Value	33,656
Recurring Basis | Long Term Investments | U.S. Government Debt and Agency Securities | Level 2
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Investments, Amortized Cost	32,634
Investments, Unrealized Gains	11
Investments, Unrealized Losses	(9)
Investments, Fair Value	32,636
Recurring Basis | Long Term Investments | U.S. Treasury Bills | Level 2
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Investments, Amortized Cost	1,020
Investments, Fair Value	$ 1,020

Fair Value - Additional Informa

Fair Value - Additional Information (Details) - USD ($)	9 Months Ended	12 Months Ended
	Sep. 30, 2020	Dec. 31, 2019	Dec. 31, 2018	Sep. 22, 2020	Dec. 31, 2017
IPO
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Public offering price per share				$ 17
Grant Liability
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Additional grant liability	$ 464,000	$ 100,000	$ 164,000
Total grant liability	$ 1,500,000	$ 1,036,000	$ 936,000		$ 772,000

Fair Value - Schedule of Fair_4

Fair Value - Schedule of Fair Value Liabilities, Activity for Convertible Preferred Stock Warrant Liability (Details) - Convertible Preferred Stock Warrant Liability $ in Thousands	9 Months Ended
	Sep. 30, 2020USD ($)
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Derivative liability recorded upon issuance of convertible notes	$ 364
Change in fair value of liability	641
Settlement	$ (1,005)

Leases - Additional Information

Leases - Additional Information (Details) - USD ($)	3 Months Ended	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2020	Dec. 31, 2019	Dec. 31, 2018
Lessee Lease Description [Line Items]
Operating lease expense	$ 34,000	$ 34,000
Variable lease expense	0	0
Short term leases, rent expense	$ 18,000	57,000
Cash paid for amounts included in measurement of lease liability		$ 21,000
Laboratory and Office Facilities
Lessee Lease Description [Line Items]
Operating lease initial term			1 year	1 year
Laboratory and Office Facilities | Bothell, Washington
Lessee Lease Description [Line Items]
Operating lease expiration month and year		2027-08
Operating lease initial term	7 years	7 years
Operating lease existence of option to extend		true
Operating lease, additional term of contract	5 years	5 years
Operating lease, remaining lease term	6 years 10 months 24 days	6 years 10 months 24 days
Incremental borrowing rate	8.20%	8.20%
Laboratory and Office Facilities | University of Washington, Seattle
Lessee Lease Description [Line Items]
Operating lease initial term	12 months	12 months

Leases - Reconciliation of Undi

Leases - Reconciliation of Undiscounted Operating Lease Cash Flows to Operating Lease Liability Payments (Details) $ in Thousands	Sep. 30, 2020USD ($)
Leases [Abstract]
2021	$ 234
2022	261
2023	269
2024	277
2025 and thereafter	779
Total undiscounted lease payments	1,820
Present value adjustment for minimum lease commitments	(457)
Tenant improvement allowance receivable	(391)
Net lease liability	$ 972