Athira Pharma (ATHA) 10-K 28 Mar 22 2021 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Mar. 21, 2022	Jun. 30, 2021
Cover [Abstract]
Document Type	10-K
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
Document Period End Date	Dec. 31, 2021
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	FY
Trading Symbol	ATHA
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	No
Entity File Number	001-39503
Entity Shell Company	false
Entity Interactive Data Current	Yes
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Address Address Line1	18706 North Creek Parkway
Entity Address Address Line2	Suite 104
Entity Address City Or Town	Bothell
Entity Address State Or Province	WA
Entity Address Postal Zip Code	98011
City Area Code	425
Local Phone Number	620-8501
Document Annual Report	true
Document Transition Report	false
Title of 12(b) Security	Common Stock, $0.0001 par value per share
Security Exchange Name	NASDAQ
Entity Common Stock, Shares Outstanding		37,624,058
Entity Public Float			$ 328.3
ICFR Auditor Attestation Flag	false
Documents Incorporated by Reference	DOCUMENTS INCORPORATED BY REFERENCE Portions of the definitive proxy statement to be delivered to stockholders in connection with the 2022 annual meeting of stockholders are incorporated by reference into Part III of this Annual Report on Form 10-K. Such proxy statement will be filed with the Securities and Exchange Commission not later than 120 days following the end of the Registrant’s fiscal year ended December 31, 2021.
Auditor Name	Ernst & Young LLP
Auditor Firm ID	42
Auditor Location	Seattle, Washington

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 110,537	$ 60,625
Short-term investments	143,222	124,057
Unbilled grant receivable	2,336	1,300
Prepaid expenses and other current assets	4,704	6,355
Total current assets	260,799	192,337
Property and equipment, net	3,757	2,649
Operating lease right-of-use asset	1,460	936
Long-term investments	65,936	83,509
Other long-term assets	56	132
Total assets	332,008	279,563
Current liabilities:
Accounts payable	567	1,158
Accrued liabilities	8,437	3,123
Current operating lease liability	288	124
Total current liabilities	9,292	4,405
Operating lease liability, less current portion	1,632	876
Total liabilities	10,924	5,281
Stockholders' equity:
Common stock, $0.0001 par value; 900,000,000 shares authorized at December 31, 2021 and December 31, 2020, respectively; 37,379,077 and 32,485,784 shares issued and outstanding at December 31, 2021 and December 31, 2020, respectively	4	3
Additional paid-in capital	417,363	315,288
Accumulated other comprehensive (loss) income	(388)	33
Accumulated deficit	(95,895)	(41,042)
Total stockholders' equity	321,084	274,282
Total liabilities and stockholders' equity	$ 332,008	$ 279,563

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2021	Dec. 31, 2020
Statement Of Financial Position [Abstract]
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares authorized	900,000,000	900,000,000
Common stock, shares issued	37,379,077	32,485,784
Common stock, shares outstanding	37,379,077	32,485,784

Consolidated Statements of Oper

Consolidated Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Operating expenses:
Research and development	$ 42,794	$ 13,286
General and administrative	21,228	6,709
Total operating expenses	64,022	19,995
Loss from operations	(64,022)	(19,995)
Grant income	8,835	1,321
Other income (expense), net	334	(1,281)
Net loss	(54,853)	(19,955)
Unrealized (loss) gain on available-for-sale securities	(421)	33
Comprehensive loss attributable to common stockholders	$ (55,274)	$ (19,922)
Net loss per share attributable to common stockholders, basic and diluted	$ (1.49)	$ (1.67)
Weighted-average shares used in computing net loss per share attributable to common stockholders, basic and diluted	36,921,172	11,966,912

Consolidated Statements of Conv

Consolidated Statements of Convertible Preferred Stock and Stockholders Equity - USD ($) $ in Thousands	Total	Convertible Preferred Stock	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit
Beginning balance at Dec. 31, 2019	$ (19,723)			$ 1,364		$ (21,087)
Temporary equity, beginning balance, shares at Dec. 31, 2019		2,617,386
Temporary equity, beginning balance at Dec. 31, 2019		$ 17,051
Beginning balance, shares at Dec. 31, 2019			3,641,449
Issuance of common stock upon exercise of common stock options	544			544
Issuance of common stock upon exercise of common stock options, shares			540,934
Issuance of Series B convertible preferred stock and common stock warrants, net of issuance costs of $3.5 million	10,591			10,591
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
Proceeds from initial public offering, net of underwriters' discounts and commissions and issuance costs	208,517		$ 2	208,515
Proceeds from initial public offering, net of underwriters' discounts and commissions and issuance costs, Shares			13,397,712
Conversion of convertible preferred stock	92,537		$ 1	92,536
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			2,402,680
Stock-based compensation	633			633
Unrealized (loss) gain on available-for-sale securities	33				$ 33
Net loss	(19,955)					(19,955)
Ending balance at Dec. 31, 2020	$ 274,282		$ 3	315,288	33	(41,042)
Ending balance, shares at Dec. 31, 2020			32,485,784
Issuance of common stock upon exercise of common stock options, shares	263,501
Issuance of common stock upon exercise of common stock options and vesting of restricted stock units	$ 327			327
Issuance of common stock upon exercise of common stock options and vesting of restricted stock units, Shares			266,653
Issuance of common stock under employee stock purchase plan	364			364
Issuance of common stock under employee stock purchase plan, shares			26,640
Proceeds from initial public offering, net of underwriters' discounts and commissions and issuance costs	96,762		$ 1	96,761
Proceeds from initial public offering, net of underwriters' discounts and commissions and issuance costs, Shares			4,600,000
Stock-based compensation	4,623			4,623
Unrealized (loss) gain on available-for-sale securities	(421)				(421)
Net loss	(54,853)					(54,853)
Ending balance at Dec. 31, 2021	$ 321,084		$ 4	$ 417,363	$ (388)	$ (95,895)
Ending balance, shares at Dec. 31, 2021			37,379,077

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Operating activities
Net loss	$ (54,853,000)	$ (19,955,000)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation	4,623,000	633,000
Depreciation expense	479,000	2,000
Other non-cash expense		1,401,000
Amortization of premiums and accretion of discounts on available-for-sale securities, net	493,000	251,000
Changes in operating assets and liabilities:
Unbilled grant receivables	(1,036,000)	(1,300,000)
Prepaid expenses and other current assets	1,650,000	(6,310,000)
Accounts payable and accrued liabilities	5,150,000	2,601,000
Operating lease liability	396,000	64,000
Grant liability		(1,500,000)
Net cash used in operating activities	(43,098,000)	(24,113,000)
Investing activities
Purchases of available-for-sale securities	(299,197,000)	(226,837,000)
Maturities of available-for-sale securities	278,639,000	19,053,000
Proceeds from sales of available-for-sale securities	18,052,000
Purchases of property and equipment	(1,573,000)	(2,320,000)
Principal payments received on stockholder note receivable		36,000
Net cash used in investing activities	(4,079,000)	(210,068,000)
Financing activities
Proceeds from exercise of common stock options and common stock warrants	327,000	643,000
Proceeds from public offering, net of issuance costs	96,762,000	208,517,000
Proceeds from issuance of convertible preferred stock and common stock warrants, net of issuance costs		81,926,000
Proceeds from issuance of convertible notes, including derivative, net of issuance costs		1,664,000
Net cash provided by financing activities	97,089,000	292,750,000
Net increase in cash and cash equivalents	49,912,000	58,569,000
Cash and cash equivalents, beginning of period	60,625,000	2,056,000
Cash and cash equivalents, end of period	110,537,000	60,625,000
Supplemental disclosures of cash flow information:
Purchases of property and equipment included in accounts payable and accrued liabilities	14,000	331,000
Deferred offering costs included in accounts payable and accrued liabilities		77,000
Allocation of proceeds to common stock warrants issued in Series B convertible preferred stock financing		10,591,000
Issuance of Series B-1 preferred stock upon conversion of promissory notes		4,515,000
Recognition of warrant liability in connection with Series B convertible preferred stock financing		364,000
Recognition of derivative liability upon issuance of convertible notes		774,000
Conversion of convertible preferred stock upon closing of initial public offering		92,537,000
Right-of-use asset obtained in exchange for new operating lease liability	$ 680,000	$ 975,000

Description of Business

Description of Business	12 Months Ended
	Dec. 31, 2021
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Description of Business	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 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 consolidated financial statements and notes to the consolidated financial statements have been retroactively adjusted for all periods presented to reflect the reverse stock split. Initial Public Offering In September 2020, the Company completed its initial public offering of common stock (“IPO”) in which the Company issued and sold 12,000,000 shares of common stock at a public offering price of $ 17.00 per share, resulting in net proceeds of $ 186.4 million after deducting underwriting discounts and commissions and offering expenses paid by the Company. In October 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 and offering costs resulting in additional net proceeds to the Company of approximately $ 22.1 million. 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 the Company’s IPO, all outstanding common stock warrants were exercised into 1,085,334 shares of common stock. Additionally, all outstanding Series B convertible preferred stock warrants were remeasured to their fair value. The final remeasurement of the Series B convertible preferred stock warrant liability resulted in a $ 0.6 million loss which was recorded to other income (expense), net. Following remeasurement, all Series B convertible preferred stock warrants automatically net exercised into 59,093 shares of common stock and the corresponding liability was reclassified to additional paid in capital. Following the IPO, there are no shares of convertible preferred stock, common stock warrants, or Series B convertible preferred stock warrants outstanding. Follow-on Public Offering In January 2021, the Company completed a follow-on public offering of its common stock. As part of the follow-on offering, the Company issued and sold 4,000,000 shares of its common stock at a public offering price of $ 22.50 per share. The Company received net proceeds of approximately $ 84.1 million from the follow-on offering, after deducting underwriting discounts and commissions and offering costs. In February 2021, the Company sold an additional 600,000 shares of common stock to the underwriters of the follow-on public offering upon full exercise of the underwriters’ option to purchase additional shares at the follow-on public offering price of $ 22.50 per share, less underwriting discounts and commissions and offering costs resulting in additional net proceeds to the Company of approximately $ 12.7 million. 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 December 31, 2021, it has raised aggregate net cash proceeds of $ 407.4 million primarily from the issuance of its common stock, convertible preferred stock, common stock warrants, and convertible notes. As of December 31, 2021, the Company had $ 319.7 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 $ 319.7 million of cash, cash equivalents, and investments at December 31, 2021 will be sufficient to fund its operating expenses and capital expenditure requirements through at least the next 12 months following the date of the Company’s Annual Report on Form 10-K.

Significant Accounting Policies

Significant Accounting Policies	12 Months Ended
	Dec. 31, 2021
Accounting Policies [Abstract]
Significant Accounting Policies	2 . Significant Accounting Policies Basis of Presentation The 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 since its creation, the Australian subsidiary’s financial position and results of operations are consolidated in the accompanying consolidated financial statements. Certain prior period amounts have been reclassified to conform to current period presentation. 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. Actual results could differ from those estimates. 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 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 income or 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. 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. Property and Equipment Property and equipment consist of computer equipment, computer software, laboratory equipment, leasehold improvements and furniture and office equipment. Property and equipment are recorded at cost and depreciation is recognized using the straight-line method based on estimated useful life, generally three to five years . Leasehold improvements are amortized over the shorter of their useful life or the remaining lease term. Maintenance and repairs are charged to expense as incurred, and costs of improvements are capitalized. The Company reviews long-lived assets for impairment whenever events or circumstances indicate the carrying amount of an asset group may not be recoverable. Should an impairment exist, the impairment loss would be measured based on the excess of the asset's carrying amount over its fair value. Gains and losses from asset disposals and impairment losses are classified within the consolidated statements of operations and comprehensive loss in accordance with the use of the asset. There were no impairment losses in the years ended December 31, 2021 and 2020 as there have been no events warranting an impairment analysis. Fair Value Measurements The carrying amounts of certain financial instruments, including cash, cash equivalents, investments, accounts payable and accrued expenses approximate their fair values due to the short-term nature of those financial instruments. The fair values of the grant liability to Washington Life Sciences Discovery Fund (“LSDF”), currently managed by the Washington State Department of Commerce, 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 were accounted for as liabilities at fair value, because the shares underlying the warrants contained 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 and comprehensive loss. The Company adjusted the liability for the final change in the fair value of these warrants immediately preceding their automatic exercise in connection with the Company’s IPO. Subsequent to the Company’s IPO, the corresponding liability was reclassified to additional paid in capital. Grant Liability The grant liability associated with the grants from the Washington LSDF was accounted for under Accounting Standards Codification (“ASC”) 825-10, Financial Instruments − Overall. The estimated fair value of the grant liability was reassessed at each balance sheet date, with changes in fair value reflected in other income (expense), net. The Company estimated the fair value of the grant liability by using a discounted cash flow simulation methodology that assigns probabilities to the timing and likelihood of each triggering event, a discount rate based on market data for securities with similar durations and credit ratings to the Company, and the expected payment amount. The assumptions used to calculate the fair value of the grant liability were subject to significant judgment. 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 and repaid in full as of December 31, 2020. See Note 7. Derivative Liability, Convertible Notes Discount and Amortization The Company’s convertible notes (see Note 8) had conversion and redemption features that met the definition of an embedded derivative and were therefore subject to derivative accounting. The initial fair value of the derivative was recorded as a discount to the convertible notes, with a corresponding derivative liability. The discount to the convertible notes was 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 was recorded at estimated fair value on a recurring basis. Any changes in fair value were reflected in other income (expense), net in the statements of operations and comprehensive loss at each period end while such instruments were 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 10. Grant Income Grant income in the accompanying consolidated statements of operations and comprehensive loss consisted of the following (in thousands): Year Ended December 31, 2021 2020 Alzheimer's Association Part the Cloud $ — $ 245 National Institutes of Health Grant 8,835 1,076 Total grant income $ 8,835 $ 1,321 Amounts recorded in the accompanying consolidated balance sheets as unbilled grant receivable from these granting agencies were as follows (in thousands): December 31, 2021 2020 Alzheimer's Association Part the Cloud Research $ — $ 224 National Institutes of Health Grant 2,336 1,076 Total unbilled grant receivable $ 2,336 $ 1,300 In January 2019, the Alzheimer’s Association awarded the Company a $ 1.0 million Part the Cloud research grant. Grant proceeds must be used to advance the Company’s fosgonimeton product candidate in the Alzheimer’s disease setting. Reporting of expenses incurred supported by the grant as well as research updates are sent to the Alzheimer’s Association semi-annually. Under the terms of the agreement, the Company received $ 776,000 in 2019 and received the remaining $ 224,000 in March 2021 after having completed certain development milestones in October 2020. The Company recognized income related to the Part the Cloud research grant as qualifying expenses under the grant agreement were incurred. In December 2020, the Company accepted a grant from the National Institute on Aging (“NIA”) of the National Institutes of Health (“NIH”) to support its ACT-AD Phase 2 clinical trial for fosgonimeton, the Company’s lead therapeutic candidate being developed for the treatment of individuals with mild-to-moderate Alzheimer’s disease. Under the terms of the agreement, the Company may potentially receive $ 7.8 million with the potential for an additional $ 7.4 million, up to an aggregate of $ 15.2 million. The Company recognizes income related to the NIH grant as qualifying expenses under the grant agreement are incurred. The Company received cash of $ 7.6 million related to the NIH grant during the year ended December 31, 2021. Research and Development Expenses Research and development expenses consist primarily of direct and indirect costs incurred for research activities, including development of the 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 expensed 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. 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. Leases The Company adopted Accounting Standards Codification (“ASC”) Topic 842 - Leases effective January 1, 2020 . The Company determines if an arrangement contains a lease at inception. The Company performed an evaluation of contracts in accordance with ASC 842 and has determined it has an operating lease agreement for the laboratory and office facilities that the Company occupies. Operating lease right-of-use (“ROU”) assets and operating lease liabilities are recognized at the date the underlying asset becomes available for the Company’s use. Operating lease liabilities are based on the present value of the future minimum lease payments over the lease term. ROU assets are measured at the amount of the lease liability, adjusted for any initial direct costs incurred and any lease payments made at or before the lease commencement date, less lease incentives received. As the Company’s leases generally do not provide an implicit interest rate, the present value of the future minimum lease payments is determined using the Company’s incremental borrowing rate. This rate is an estimate of the collateralized borrowing rate the Company would incur on its future lease payments over a similar term and is based on the information available to the Company at the lease commencement date, discussed in more detail below. The Company’s leases contain options to extend the leases; lease terms are adjusted for these options only when it is reasonably certain the Company will exercise these options. The Company’s lease agreements do not contain residual value guarantees or covenants. The Company has made a policy election regarding its real estate leases not to separate non-lease components from lease components, to the extent they are fixed. Non-lease components that are not fixed are expensed as incurred as variable lease expense. The Company’s lease includes variable non-lease 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. The grant date fair value of restricted stock units is based upon the fair market value of the Company’s common stock based on its closing price as reported on the date of grant on the Nasdaq Global Select Market. 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 and restricted stock unit grants subject to performance-based milestone vesting over the remaining implicit 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. 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 Attributable to Common Stockholders Comprehensive loss attributable to common stockholders consists of net loss and other gains and losses affecting stockholders’ equity that, under U.S. GAAP, are excluded from net loss. The Company’s comprehensive loss attributable to common stockholders is comprised of net loss and unrealized gains and losses on available-for-sale securities. 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. Foreign Currency Transaction Remeasurement Adjustments Monetary assets and liabilities denominated in foreign currencies were translated into U.S. dollars, the reporting currency, at the exchange rate prevailing at the balance sheet date. Income and expenses denominated in foreign currencies were translated into U.S. dollars at the average exchange rate for the period and the transaction remeasurement adjustments are reported within other income (expense), net in the consolidated statement of operations and comprehensive loss. The functional currency of the Company’s Australian subsidiary is the U.S. dollar. 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 opts out of the extended transition period provided in the JOBS Act, unless early adoption is permitted. 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 June 2016, the FASB issued ASU 2016-13, Financial Instruments: Credit Losses (Topic 326) as clarified in ASU 2019-04, ASU 2019-05, and ASU 2020-02. The objective of the standard is to provide information about expected credit losses on financial instruments at each reporting date and to change how other-than-temporary impairments on investment securities are recorded. The ASU will become effective beginning January 1, 2023, with early adoption permitted. The Company is currently evaluating the potential impacts of the ASU on its financial condition, results of operations, cash flows and financial statement disclosures. Although there were several other new accounting pronouncements issued or proposed by the FASB, the Company does not believe any of these have had or will have material impact on its consolidated financial statements.

Fair Value

Fair Value	12 Months Ended
	Dec. 31, 2021
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 tables reflects the Company’s financial asset balances measured on a recurring basis (in thousands): December 31, 2021 Level Amortized Unrealized Unrealized Fair Cash equivalents: Money market fund 1 $ 57 $ — $ — $ 57 Commercial paper 2 96,120 — ( 5 ) 96,115 Total cash equivalents $ 96,177 $ — $ ( 5 ) $ 96,172 Short-term investments: Commercial paper 2 74,170 — ( 35 ) 74,135 U.S. government debt, municipal 2 62,149 2 ( 59 ) 62,092 Corporate bonds 2 7,004 — ( 9 ) 6,995 Total short-term investments $ 143,323 $ 2 $ ( 103 ) $ 143,222 Long-term investments: Corporate bonds 2 3,307 — ( 20 ) 3,287 U.S. government debt and agency 2 62,911 — ( 262 ) 62,649 Total long-term investments $ 66,218 $ — $ ( 282 ) $ 65,936 December 31, 2020 Level Amortized Unrealized Unrealized Fair Cash equivalents: Money market fund 1 $ 5 $ — $ — $ 5 Commercial paper 2 44,318 — ( 2 ) 44,316 U.S. government debt and agency 2 4,999 — — 4,999 U.S. treasury bills 2 4,450 — — 4,450 Total cash equivalents $ 53,772 $ — $ ( 2 ) $ 53,770 Short-term investments: Commercial paper 2 77,272 1 ( 4 ) 77,269 U.S. government debt and agency 2 31,835 7 — 31,842 U.S. treasury bills 2 14,029 — ( 3 ) 14,026 Corporate bonds 2 920 — — 920 Total short-term investments $ 124,056 $ 8 $ ( 7 ) $ 124,057 Long-term investments: U.S. government debt and agency 2 78,924 32 — 78,956 U.S. treasury bills 2 4,551 2 — 4,553 Total long-term investments $ 83,475 $ 34 $ — $ 83,509 All the commercial paper, U.S. government debt, municipal bonds and agency securities, U.S. treasury bills, and corporate bonds designated as short-term investments have an effective maturity date that is equal to or less than one year from the respective balance sheet date. Those that are designated as long-term investments have an effective maturity date that is more than one year , but less than two years , from the respective balance sheet date. 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 of 2020 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 7), and the derivative was settled upon the Company’s conversion of its convertible notes in May 2020 (see Note 8). 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 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 (in thousands): Year Ended December 31, 2020 Fair value at beginning of period $ 1,036 Change in fair value of grant liability 464 Grant liability settled upon completion of IPO ( 1,500 ) Fair value at end of period $ — The following table presents the activity for the derivative liability (in thousands): Year Ended December 31, 2020 Fair value at beginning of period $ 999 Derivative liability recorded upon issuance of 774 Change in fair value of derivative liability 132 Derivative liability settled upon conversion of ( 1,905 ) Fair value at end of period $ — The following table presents the activity for the convertible preferred stock warrant liability (in thousands): Year Ended December 31, 2020 Fair value at beginning of period $ — Recognition of convertible preferred stock 364 Change in fair value 641 Settlement upon IPO ( 1,005 ) Fair value at end of period $ — Prior to the IPO, the activity for the convertible preferred stock warrant liability presented in the table above was shown in the Company’s financial statements as level 3. Following the IPO, the preferred stock warrant liability was revalued based on the IPO price of $ 17.00 per share.

Property and Equipment, Net

Property and Equipment, Net	12 Months Ended
	Dec. 31, 2021
Property Plant And Equipment [Abstract]
Property and Equipment, Net	4. Property and Equipment, Net Property and equipment consisted of the following (in thousands): December 31, 2021 2020 Lab equipment $ 268 $ 81 Office furniture, fixtures, and 325 — Leasehold improvement 2,563 — Construction in progress 1,124 2,639 Property and equipment, at cost 4,280 2,720 Less: accumulated depreciation ( 523 ) ( 71 ) Property and equipment, net $ 3,757 $ 2,649 Depreciation expense was $ 479,000 and $ 2,000 for the years ended December 31, 2021 and 2020, respectively.

Accrued Liabilities

Accrued Liabilities	12 Months Ended
	Dec. 31, 2021
Payables And Accruals [Abstract]
Accrued Liabilities	5 . Accrued Liabilities Accrued liabilities consisted of the following (in thousands): December 31, 2021 2020 Research and development expenses $ 5,723 $ 1,169 Employee compensation and benefits 1,907 1,624 Professional services and other 807 330 Total accrued liabilities $ 8,437 $ 3,123

Other Income (Expense), Net

Other Income (Expense), Net	12 Months Ended
	Dec. 31, 2021
Other Income And Expenses [Abstract]
Other Income (Expense), Net	6 . Other Income (Expense), Net Other income (expense), net consisted of the following (in thousands): Year Ended December 31, 2021 2020 Interest and other income $ 337 $ 124 Interest expense ( 3 ) ( 367 ) Change in fair value of derivative liability — ( 132 ) Change in fair value of grant liability — ( 464 ) Change in convertible preferred stock — ( 641 ) Gain on extinguishment of convertible notes — 199 Total other income (expense), net $ 334 $ ( 1,281 )

Significant Agreements

Significant Agreements	12 Months Ended
	Dec. 31, 2021
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Significant Agreements	7 . Significant Agreements Washington State University (“WSU”) License Agreement The Company is party to an amended and restated exclusive license agreement with sublicensing terms between the Company and Washington State University (“WSU”) that the Company entered into in 2015. Under this agreement, the Company has an exclusive license to make, use, sell, and offer for sale products covered by certain licensed patents, including dihexa, the chemical compound into which fosgonimeton metabolizes following administration. To keep in good standing, the agreement requires the Company to meet certain development milestones and pay annual maintenance fees. All contractual requirements have been met as of December 31, 2021. During the year ended December 31, 2020, the Phase 2 clinical trial milestone had been reached and a payment of $ 50,000 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; and • $ 600,000 – Upon receipt of 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 December 31, 2021, no sales of any licensed products had occurred and the Company had no t 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 based upon the sublicense consideration received in such event. 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 December 31, 2021, the Company has not entered into or incurred any liability from a sublicense agreement. LSDF 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 was accounted for under ASC 825-10, Financial Instruments − Overall. The estimated fair value of the grant liability was reassessed at each balance sheet date, with changes in fair value reflected in other income (expense), net. To determine the estimated fair value of the grant liability, the Company used a discounted cash flow simulation methodology that assigns probabilities to the timing and likelihood of each triggering event, a discount rate based on market data for securities with similar durations and credit ratings to the Company, and the expected payment amount. The assumptions used to calculate the fair value of the grant liability were subject to significant judgment, and payment may have been in an amount different from the liability that the Company estimated. However, total payments under the agreements would not exceed $ 1.5 million. 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 prior to settlement. The change in the fair value of the liability resulted in expense of approximately $ 464,000 for the year ended December 31, 2020, which was included in other income (expense), net in the accompanying consolidated statements of operations and comprehensive loss.

Convertible Notes

Convertible Notes	12 Months Ended
	Dec. 31, 2021
Debt Disclosure [Abstract]
Convertible Notes	8 . 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 $ 0.9 million and $ 1.3 million in 2019 and 2018, respectively. The notes accrued interest at a rate of 5 % per year and mature in December 2021 , unless earlier converted. No principal or interest was payable prior to maturity as the convertible notes and any accrued interest would 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 have also elected 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 experienced a change in control, holders may have either converted the outstanding principal amount plus any accrued interest into shares of common stock at the then fair value of common stock or may have required 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 . The fair value of the embedded derivative was determined using a discounted cash flow simulation methodology that assigns probabilities to the timing and likelihood of each event. The discount rate was determined based on market interest rate data for securities with similar durations and credit ratings to the convertible notes. The fair value of the embedded derivative was recorded as a liability with an offsetting amount recorded as a discount on the convertible notes at each issuance. The discount is being amortized to interest expense using the effective interest method over the contractual term of the notes. 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 .

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2021
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	9 . Commitments and Contingencies Legal Proceedings From time to time, we are subject to various legal proceedings or claims that arise in the ordinary course of business. We accrue a liability when management believes that it is both probable that a liability has been incurred and the amount of loss can be reasonably estimated, and as of December 31, 2021, we have not recorded any such liabilities. The following is a brief description of the more significant legal proceedings. Securities Class Actions On June 25, 2021 , plaintiffs Fan Wang and Hang Gao filed a putative securities class action lawsuit in the U.S. District Court for the Western District of Washington against the Company and the Company’s former Chief Executive Officer Dr. Leen Kawas, captioned Wang v. Athira Pharma, Inc., et al. , No. 2:21-cv-00861. Plaintiffs Wang and Gao assert claims under Sections 10(b) and 20(a) of the Securities Exchange Act of 1934 and SEC Rule 10b-5, alleging that the defendants made materially false and misleading statements and omitted material adverse facts regarding the Company’s business. Specifically, the Wang plaintiffs allege that the Company failed to disclose to investors that certain research conducted by Dr. Kawas was allegedly tainted by scientific misconduct during her doctoral work at WSU, including the manipulation of data, and that as a result, the defendants’ positive statements about the Company’s business, operations, and prospects were materially misleading. The Wang plaintiffs seek unspecified compensatory and punitive damages, and reasonable costs and expenses, including attorneys’ fees. That same day, on June 25, 2021 , plaintiff Harshdeep Jawandha filed a putative securities class action lawsuit in the U.S. District Court for the Western District of Washington against the Company, Dr. Kawas, the Company’s Chief Financial Officer, certain members of the Company’s board of directors at the time of the Company’s IPO, as well as the IPO underwriters, captioned Jawandha v. Athira Pharma, Inc., et al. , No. 2:21-cv-00862. The Jawandha complaint asserts violations of Sections 11 and 15 of the Securities Act of 1933, alleging that that the Company’s IPO registration statement was materially false and misleading because it omitted to state that certain of Dr. Kawas’s published doctoral research papers at WSU contained allegedly improperly altered images, that the research was allegedly foundational to the Company’s efforts to develop treatments for Alzheimer’s disease, and that the defendants’ positive statements about the Company’s business, operations, and prospects were materially misleading. The plaintiff seeks unspecified compensatory damages, and reasonable costs and expenses, including attorneys’ fees. Also on June 25, 2021 , plaintiffs Timothy Slyne and Tai Slyne filed a putative securities class action lawsuit in the U.S. District Court for the Western District of Washington against the Company, Dr. Kawas, the Company’s Chief Financial Officer, and the same members of the Company’s board of directors and underwriters as in the Jawandha complaint, captioned Slyne v. Athira Pharma, Inc. et al. , No. 2:21-cv-00864. The Slyne complaint asserts violations of Sections 11 and 15 of the Securities Act of 1933, alleging that purported issues with Dr. Kawas’s doctoral research at WSU should have been disclosed in the Company’s IPO registration statement. The Slyne plaintiffs seek unspecified compensatory damages, reasonable costs and expenses, including attorneys’ fees, and injunctive and other equitable relief. On August 9, 2021, the district judge presiding over Wang v. Athira Pharma, Inc., et al. , No. 2:21-cv-00861, issued an order consolidating the three cases under that case number. On October 5, 2021, the district court issued an order appointing lead plaintiffs and approved their selection of lead and liaison counsel. On January 7, 2022, lead plaintiffs filed a consolidated amended complaint, which asserts violations of Sections 10(b) and 20(a) of the Securities Exchange Act of 1934 and SEC Rule 10b-5 and Sections 11, 12, and 15 of the Securities Act of 1933. The consolidated amended complaint is brought against the Company, Dr. Kawas, the Company’s chief financial officer, certain members of our board of directors at the time of our IPO and secondary public offering (SPO), and the IPO and SPO underwriters. As with the previous complaints, it is based on allegations that the IPO and SPO registration statements and/or other public statements were materially false and misleading because they omitted to state that certain of Dr. Kawas’s published doctoral research papers at WSU contained allegedly improperly altered images. Lead plaintiffs seek unspecified compensatory damages, equitable and injunctive relief, and reasonable costs and expenses, including attorneys’ fees, on behalf of themselves and the purported class. On March 8, 2022, the defendants filed a motion to dismiss lead plaintiffs’ consolidated amended complaint for failure to state a claim under the federal securities laws. The Company cannot predict the outcome of these suits, and failure by the Company to obtain a favorable resolution of these suits could have a material adverse effect on its business, results of operations and financial condition. The Company’s chances of success on the merits are still uncertain and any possible loss or range of loss cannot be reasonably estimated and as such the Company has not recorded a liability as of December 31, 2021. 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 enters 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. Operating Leases The Company has operating leases for laboratory and office facilities in Bothell, Washington that expire in August 2027 . The initial terms of the leases range from 6.3 to 7 years and the Company has options to extend the leases for an additional five years that it is not reasonably certain to exercise. As of December 31, 2021, 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): December 31, 2022 452 2023 466 2024 480 2025 494 Thereafter 856 Total undiscounted lease payments 2,748 Present value adjustment for minimum lease ( 548 ) Tenant improvement allowance receivable ( 280 ) Net lease liability $ 1,920 The weighted average remaining lease term and the weighted average discount rate used to determine the operating lease liability were as follows: December 31, Weighted average remaining lease term (years) 5.9 Weighted average discount rate 8.1 % Operating lease expense was $ 323,000 for the year ended December 31, 2021. Separately, variable lease expense was $ 108,000 for operating leases during the year ended December 31, 2021.

Convertible Preferred Stock

Convertible Preferred Stock	12 Months Ended
	Dec. 31, 2021
Equity [Abstract]
Convertible Preferred Stock	10 . Convertible Preferred Stock 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

Common Stock

Common Stock	12 Months Ended
	Dec. 31, 2021
Equity [Abstract]
Common Stock	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 Company’s 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: December 31, 2021 2020 Shares issuable upon the exercise of outstanding 2,632,396 1,974,870 Shares available for future grant under the 2020 4,442,315 3,742,235 Shares available for future grant under the 621,211 323,000 Total 7,695,922 6,040,105 The Company’s 2020 Equity Incentive Plan (“2020 Plan”) provides for annual increases in the number of shares that may be issued under the 2020 Plan on January 1, 2021 and each subsequent January 1, thereafter, by a number of shares equal to the least of (a) 3,230,000 shares, (b) 5 % of the number of shares of common stock issued and outstanding on the immediately preceding December 31, or (c) an amount determined by the Company’s board of directors. The Company’s 2020 Employee Stock Purchase Plan (“ESPP”) provides for annual increases in the number of shares that may be issued under the ESPP on January 1, 2021 and each subsequent January 1, thereafter, by a number of shares equal to the least of (a) 646,000 shares, (b) 1 % of the number of shares of common stock issued and outstanding on the immediately preceding December 31, or (c) an amount determined by the Company’s board of directors. Effective January 1, 2021, the Company’s 2020 Plan and ESPP reserves increased by 1,624,259 shares and 324,851 shares, respectively. Effective January 1, 2022, the Company’s 2020 Plan and ESPP reserves increased by 1,868,953 shares and 373,790 shares, respectively.

Stock-based Compensation

Stock-based Compensation	12 Months Ended
	Dec. 31, 2021
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock-based Compensation	12. Stock-based Compensation Stock‑based compensation expense recognized was as follows (in thousands): Year Ended December 31, 2021 2020 Research and development $ 1,368 $ 215 General and administrative 3,255 418 Total stock-based compensation expense $ 4,623 $ 633 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 —Prior to the closing of the Company’s initial public offering, 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. For valuations of grants made after the closing of the Company’s initial public offering, the fair value of each share of common stock is based on the closing price of the Company’s common stock on the date of grant, or other relevant determination date, as reported on The Nasdaq Global Select Market. • 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: Year Ended December 31, 2021 2020 Risk-free interest rate 0.99 % 0.49 % Expected volatility 90.91 % 87.41 % Expected term (in years) 6.10 6.87 Expected dividend yield — — The grant date fair value of restricted stock units is based upon the fair market value of the Company’s common stock based on its closing price as reported on the date of grant on the Nasdaq Global Select Market. The weighted-average grant-date fair value of options granted during the years ended December 31, 2021 and 2020 were $ 14.4 million and $ 4.2 million respectively. The weighted-average grant-date fair value of restricted stock units granted during the year ended December 31, 2021 was $ 5.7 million. No restricted stock units were granted during the year ended December 31, 2020. Stock Option Activity Changes in shares available for grant under the 2020 Plan during the year ended December 31, 2021 were as follows: Shares Shares available for grant at December 31, 2020 3,742,235 2020 Plan reserve increase on January 1, 2021 1,624,259 Options and restricted stock units granted ( 1,392,928 ) Options and restricted stock units forfeited, 468,749 Shares available for grant at December 31, 2021 4,442,315 A summary of option activity for the year ended December 31, 2021 was as follows: Shares Weighted- Weighted- Aggregate Balance at December 31, 2020 1,974,870 $ 9.31 7.98 $ 49,275 Granted 1,024,776 18.83 Exercised ( 263,501 ) 1.24 Forfeited/expired ( 465,249 ) 18.02 Balance at December 31, 2021 2,270,896 $ 12.76 7.22 $ 8,306 Expected to vest 1,457,586 $ 16.08 8.98 $ 1,925 Options exercisable 813,310 $ 6.80 4.05 $ 6,380 The total fair value of options granted that vested during the years ended December 31, 2021 and 2020 was $ 1.4 million and $ 271,000 , respectively. 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 December 31, 2021. The aggregate intrinsic value of options exercised was $ 3.1 million and $ 18.0 million during the year ended December 31, 2021 and 2020, respectively, determined as of the date of option exercise. As of December 31, 2021, there was $ 10.2 million of total unrecognized compensation cost related to non-vested stock options. The Company expects to recognize this cost over a remaining weighted-average period of 1.52 years. The Company utilizes newly issued shares to satisfy option exercises. Stock options outstanding and exercisable consisted of the following at December 31, 2021: Employees and Directors Non-employees Exercise Price ($) Shares Shares Shares Shares 0.16 to 1.00 209,780 209,780 — — 1.04 to 1.49 364,524 222,659 113,642 93,150 17.00 to 19.94 989,576 210,071 195,453 60,684 20.55 to 29.41 397,921 16,966 — — Total 1,961,801 659,476 309,095 153,834 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 non-vested shares for no consideration. There were 4,204 shares subject to repurchase as of December 31, 2020, all of which were related to non-employee RSAs. A summary of RSA activity for the year ended December 31, 2021 was as follows: Share Weighted- Non-vested at December 31, 2020 4,204 $ 1.35 Granted — — Vested ( 4,204 ) 1.35 Non-vested at December 31, 2021 — $ — Restricted Stock Unit Activity During the year ended December 31, 2021, the Company issued restricted stock unit (“RSU”) awards to an advisor and employees under the 2020 Plan. A summary of RSU activity for the year ended December 31, 2021 is as follows: Share Weighted- Non-vested at December 31, 2020 — $ — Granted 368,152 15.37 Cancelled ( 3,500 ) 15.34 Vested ( 3,152 ) 21.15 Non-vested at December, 2021 361,500 $ 15.32 In November 2021, the Company granted RSUs equivalent to 365,000 shares of the Company’s common stock to employees under the 2020 Plan with a grant date fair value of $ 5.6 million. The RSUs will vest upon achievement of certain clinical development milestones, subject to continued service to the Company during the vesting period. As of December 31, 2021, unrecognized stock-based compensation expense related to non-vested restricted stock units was $ 4.8 million, which is expected to be recognized over a remaining weighted-average period of 1.33 years Employee Stock Purchase Plan In August 2020, the Company’s board of directors adopted the 2020 Employee Stock Purchase Plan (“ESPP”) which became effective in September 2020. Under the ESPP, eligible employees can authorize payroll deductions for amounts up to the lesser of 15 % of their qualifying wages or the statutory limit under the U.S. Internal Revenue Code. The ESPP provides for offering periods of six months in duration with one purchase period per offering period beginning May 18 and November 18 of each year. Participants in an offering period will be granted the right to purchase common shares at a price per share that is 85 % of the lesser of the fair market value of the shares at (i) the first day of the offering period or (ii) the end of each purchase period within the offering period. A maximum of 5,000 shares of common stock may be purchased by each participant at the purchase date during the offering period. The fair value of the ESPP options granted is determined using the Black-Scholes model and is amortized on a straight-line basis. The number of shares reserved for the ESPP automatically increases each year, beginning on January 1, 2021 by the lesser of (i) 646,000 shares of common stock, (ii) 1 % of the outstanding shares of common stock on the last day of the immediately preceding fiscal year, or (iii) such number of shares determined by the board no later than the last day of the immediately preceding fiscal year. As of December 31, 2021, 621,211 shares of common stock were reserved for future grants under the ESPP. On January 1, 2022, an additional 373,790 shares of common stock became available for future grants under the ESPP. Stock-based compensation expense recognized during the years ended December 31, 2021 and 2020 associated with the ESPP was $ 164,000 and $ 46,000 , respectively. During the year ended December 31, 2021, the Company issued 26,640 shares of common stock to service providers under the ESPP.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2021
Income Tax Disclosure [Abstract]
Income Taxes	13. Income Taxes Components of Income and Income Tax The Company did not record a provision (benefit) for income taxes for the years ended December 31, 2021 and 2020. Net loss is attributable to the following tax jurisdictions (in thousands): Year Ended December 31, 2021 2020 United States $ ( 54,963 ) $ ( 19,969 ) Foreign 110 14 Net Loss $ ( 54,853 ) $ ( 19,955 ) 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, 2021 2020 Federal statutory income tax rate 21.0 % 21.0 % State Taxes 1.2 — Non-deductible expenses and others 0.2 0.2 Non-deductible expense related to the — ( 1.0 ) Non-deductible expense related to the grant — ( 0.1 ) Tax credits 2.2 1.5 Change in valuation allowance ( 24.6 ) ( 21.6 ) Effective income tax rate — % — % Deferred Tax Assets and Liabilities The components of the Company’s deferred tax assets and liabilities were as follows (in thousands): Year Ended December 31, 2021 2020 Deferred tax assets: Net operating loss carryforwards $ 19,543 $ 8,090 Research and development tax credit 2,166 1,011 Accrued liabilities 392 295 Stock-based compensation 804 106 Operating lease liability 426 210 Other 224 72 Total deferred tax assets 23,555 9,784 Deferred tax liabilities: Right of use asset ( 324 ) ( 197 ) Prepaid expenses and other ( 664 ) ( 489 ) Total deferred tax liabilities ( 988 ) ( 686 ) Less valuation allowance ( 22,567 ) ( 9,098 ) 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, 2021, 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 $ 13.5 million and $ 4.3 million during 2021 and 2020, respectively. At December 31, 2021, the Company has federal net operating loss and tax credit carryforwards of $ 9.5 million and $ 2.9 million, respectively, which expire over a period of 10 to 16 years . Net operating loss carryforwards of $ 80.7 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 for uncertain tax positions were as follows (in thousands): Year Ended December 31, 2021 2020 Beginning balance $ 337 $ 239 Additions for tax positions taken in the current 385 98 Ending balance $ 722 $ 337 If the unrecognized tax benefits for uncertain tax positions as of December 31, 2021 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 consolidated financial statements. At December 31, 2021, 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, 2021
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 no t make any matching contributions for the years ended December 31, 2021 or 2020.

Net Loss Per Share Attributable

Net Loss Per Share Attributable to Common Stockholders	12 Months Ended
	Dec. 31, 2021
Earnings Per Share [Abstract]
Net Loss Per Share Attributable to Common Stockholders	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, 2021 2020 Non-vested RSAs — 4,204 Non-vested RSUs 361,500 — Stock options to purchase common stock 2,270,896 1,974,870 Employee stock purchase plan 1,277 3,995 Total 2,633,673 1,983,069

Immaterial Error Correction (Un

Immaterial Error Correction (Unaudited)	12 Months Ended
	Dec. 31, 2021
Prior Period Adjustment [Abstract]
Immaterial Error Correction (Unaudited)	16. Immaterial Error Correction (Unaudited) In connection with the preparation of the consolidated statements of operations and comprehensive loss for the year ended December 31, 2021, the Company identified immaterial errors in the calculation of the weighted-average number of common shares outstanding, basic and diluted, for certain of its year-to-date periods presented in its interim financial statements, resulting in an understatement in the weighted average common shares outstanding and an overstatement in the net loss per share, basic and diluted. This error was revised as shown in the table below. The error did not impact the weighted average common shares outstanding, basic and diluted, for any three-month period and had no impact on net loss, comprehensive loss, total assets, or stockholders' equity. The impact of the error was as follows: Six Months Ended June 30, 2021 As Reported Adjustment As Adjusted Weighted average shares outstanding, 33,813,104 2,685,900 36,499,004 Net loss per share, basic $ ( 0.68 ) $ 0.05 $ ( 0.63 ) Nine Months Ended September 30, 2021 As Reported Adjustment As Adjusted Weighted average shares outstanding, 34,315,047 2,458,053 36,773,100 Net loss per share, basic $ ( 1.12 ) $ 0.07 $ ( 1.05 )

Significant Accounting Polici_2

Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2021
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The 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 since its creation, the Australian subsidiary’s financial position and results of operations are consolidated in the accompanying consolidated financial statements. Certain prior period amounts have been reclassified to conform to current period presentation.
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. Actual results could differ from those estimates.
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 income or 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.
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.
Property and Equipment	Property and Equipment Property and equipment consist of computer equipment, computer software, laboratory equipment, leasehold improvements and furniture and office equipment. Property and equipment are recorded at cost and depreciation is recognized using the straight-line method based on estimated useful life, generally three to five years . Leasehold improvements are amortized over the shorter of their useful life or the remaining lease term. Maintenance and repairs are charged to expense as incurred, and costs of improvements are capitalized. The Company reviews long-lived assets for impairment whenever events or circumstances indicate the carrying amount of an asset group may not be recoverable. Should an impairment exist, the impairment loss would be measured based on the excess of the asset's carrying amount over its fair value. Gains and losses from asset disposals and impairment losses are classified within the consolidated statements of operations and comprehensive loss in accordance with the use of the asset. There were no impairment losses in the years ended December 31, 2021 and 2020 as there have been no events warranting an impairment analysis.
Fair Value Measurements	Fair Value Measurements The carrying amounts of certain financial instruments, including cash, cash equivalents, investments, accounts payable and accrued expenses approximate their fair values due to the short-term nature of those financial instruments. The fair values of the grant liability to Washington Life Sciences Discovery Fund (“LSDF”), currently managed by the Washington State Department of Commerce, the derivative liability, and the convertible preferred stock warrant liability were estimated using level 3 unobservable inputs.
Convertible Preferred Stock Warrant Liability	Convertible Preferred Stock Warrant Liability Freestanding warrants to purchase shares of the Company’s convertible preferred stock were accounted for as liabilities at fair value, because the shares underlying the warrants contained 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 and comprehensive loss. The Company adjusted the liability for the final change in the fair value of these warrants immediately preceding their automatic exercise in connection with the Company’s IPO. Subsequent to the Company’s IPO, the corresponding liability was reclassified to additional paid in capital.
Grant Liability	Grant Liability The grant liability associated with the grants from the Washington LSDF was accounted for under Accounting Standards Codification (“ASC”) 825-10, Financial Instruments − Overall. The estimated fair value of the grant liability was reassessed at each balance sheet date, with changes in fair value reflected in other income (expense), net. The Company estimated the fair value of the grant liability by using a discounted cash flow simulation methodology that assigns probabilities to the timing and likelihood of each triggering event, a discount rate based on market data for securities with similar durations and credit ratings to the Company, and the expected payment amount. The assumptions used to calculate the fair value of the grant liability were subject to significant judgment. 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 and repaid in full as of December 31, 2020. See Note 7.
Derivative Liability Convertible Notes Discount and Amortization	Derivative Liability, Convertible Notes Discount and Amortization The Company’s convertible notes (see Note 8) had conversion and redemption features that met the definition of an embedded derivative and were therefore subject to derivative accounting. The initial fair value of the derivative was recorded as a discount to the convertible notes, with a corresponding derivative liability. The discount to the convertible notes was 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 was recorded at estimated fair value on a recurring basis. Any changes in fair value were reflected in other income (expense), net in the statements of operations and comprehensive loss at each period end while such instruments were 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 10.
Grant Income	Grant Income Grant income in the accompanying consolidated statements of operations and comprehensive loss consisted of the following (in thousands): Year Ended December 31, 2021 2020 Alzheimer's Association Part the Cloud $ — $ 245 National Institutes of Health Grant 8,835 1,076 Total grant income $ 8,835 $ 1,321 Amounts recorded in the accompanying consolidated balance sheets as unbilled grant receivable from these granting agencies were as follows (in thousands): December 31, 2021 2020 Alzheimer's Association Part the Cloud Research $ — $ 224 National Institutes of Health Grant 2,336 1,076 Total unbilled grant receivable $ 2,336 $ 1,300 In January 2019, the Alzheimer’s Association awarded the Company a $ 1.0 million Part the Cloud research grant. Grant proceeds must be used to advance the Company’s fosgonimeton product candidate in the Alzheimer’s disease setting. Reporting of expenses incurred supported by the grant as well as research updates are sent to the Alzheimer’s Association semi-annually. Under the terms of the agreement, the Company received $ 776,000 in 2019 and received the remaining $ 224,000 in March 2021 after having completed certain development milestones in October 2020. The Company recognized income related to the Part the Cloud research grant as qualifying expenses under the grant agreement were incurred. In December 2020, the Company accepted a grant from the National Institute on Aging (“NIA”) of the National Institutes of Health (“NIH”) to support its ACT-AD Phase 2 clinical trial for fosgonimeton, the Company’s lead therapeutic candidate being developed for the treatment of individuals with mild-to-moderate Alzheimer’s disease. Under the terms of the agreement, the Company may potentially receive $ 7.8 million with the potential for an additional $ 7.4 million, up to an aggregate of $ 15.2 million. The Company recognizes income related to the NIH grant as qualifying expenses under the grant agreement are incurred. The Company received cash of $ 7.6 million related to the NIH grant during the year ended December 31, 2021.
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 the 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 expensed 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.
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.
Leases	Leases The Company adopted Accounting Standards Codification (“ASC”) Topic 842 - Leases effective January 1, 2020 . The Company determines if an arrangement contains a lease at inception. The Company performed an evaluation of contracts in accordance with ASC 842 and has determined it has an operating lease agreement for the laboratory and office facilities that the Company occupies. Operating lease right-of-use (“ROU”) assets and operating lease liabilities are recognized at the date the underlying asset becomes available for the Company’s use. Operating lease liabilities are based on the present value of the future minimum lease payments over the lease term. ROU assets are measured at the amount of the lease liability, adjusted for any initial direct costs incurred and any lease payments made at or before the lease commencement date, less lease incentives received. As the Company’s leases generally do not provide an implicit interest rate, the present value of the future minimum lease payments is determined using the Company’s incremental borrowing rate. This rate is an estimate of the collateralized borrowing rate the Company would incur on its future lease payments over a similar term and is based on the information available to the Company at the lease commencement date, discussed in more detail below. The Company’s leases contain options to extend the leases; lease terms are adjusted for these options only when it is reasonably certain the Company will exercise these options. The Company’s lease agreements do not contain residual value guarantees or covenants. The Company has made a policy election regarding its real estate leases not to separate non-lease components from lease components, to the extent they are fixed. Non-lease components that are not fixed are expensed as incurred as variable lease expense. The Company’s lease includes variable non-lease 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	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. The grant date fair value of restricted stock units is based upon the fair market value of the Company’s common stock based on its closing price as reported on the date of grant on the Nasdaq Global Select Market. 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 and restricted stock unit grants subject to performance-based milestone vesting over the remaining implicit 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.
Income Taxes	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 Attributable to Common Stockholders	Comprehensive Loss Attributable to Common Stockholders Comprehensive loss attributable to common stockholders consists of net loss and other gains and losses affecting stockholders’ equity that, under U.S. GAAP, are excluded from net loss. The Company’s comprehensive loss attributable to common stockholders is comprised of net loss and unrealized gains and losses on available-for-sale securities.
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.
Foreign Currency Translation Remeasurement Adjustments	Foreign Currency Transaction Remeasurement Adjustments Monetary assets and liabilities denominated in foreign currencies were translated into U.S. dollars, the reporting currency, at the exchange rate prevailing at the balance sheet date. Income and expenses denominated in foreign currencies were translated into U.S. dollars at the average exchange rate for the period and the transaction remeasurement adjustments are reported within other income (expense), net in the consolidated statement of operations and comprehensive loss. The functional currency of the Company’s Australian subsidiary is the U.S. dollar.
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.
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 opts out of the extended transition period provided in the JOBS Act, unless early adoption is permitted. 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	Recent Accounting Pronouncements Not Yet Adopted In June 2016, the FASB issued ASU 2016-13, Financial Instruments: Credit Losses (Topic 326) as clarified in ASU 2019-04, ASU 2019-05, and ASU 2020-02. The objective of the standard is to provide information about expected credit losses on financial instruments at each reporting date and to change how other-than-temporary impairments on investment securities are recorded. The ASU will become effective beginning January 1, 2023, with early adoption permitted. The Company is currently evaluating the potential impacts of the ASU on its financial condition, results of operations, cash flows and financial statement disclosures. Although there were several other new accounting pronouncements issued or proposed by the FASB, the Company does not believe any of these have had or will have material impact on its consolidated financial statements.

Significant Accounting Polici_3

Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2021
Accounting Policies [Abstract]
Summary of Grant Income in the Accompanying Consolidated Statements of Operations and Comprehensive loss	Grant income in the accompanying consolidated statements of operations and comprehensive loss consisted of the following (in thousands): Year Ended December 31, 2021 2020 Alzheimer's Association Part the Cloud $ — $ 245 National Institutes of Health Grant 8,835 1,076 Total grant income $ 8,835 $ 1,321
Summary of Amounts Recorded in the Accompanying Consolidated Balance Sheets as Unbilled Grant Receivables from Granting Agencies	Amounts recorded in the accompanying consolidated balance sheets as unbilled grant receivable from these granting agencies were as follows (in thousands): December 31, 2021 2020 Alzheimer's Association Part the Cloud Research $ — $ 224 National Institutes of Health Grant 2,336 1,076 Total unbilled grant receivable $ 2,336 $ 1,300

Fair Value (Tables)

Fair Value (Tables)	12 Months Ended
	Dec. 31, 2021
Schedule of Fair Value of Cash Equivalents, Short-term Investments and Long-term Investments	The following tables reflects the Company’s financial asset balances measured on a recurring basis (in thousands): December 31, 2021 Level Amortized Unrealized Unrealized Fair Cash equivalents: Money market fund 1 $ 57 $ — $ — $ 57 Commercial paper 2 96,120 — ( 5 ) 96,115 Total cash equivalents $ 96,177 $ — $ ( 5 ) $ 96,172 Short-term investments: Commercial paper 2 74,170 — ( 35 ) 74,135 U.S. government debt, municipal 2 62,149 2 ( 59 ) 62,092 Corporate bonds 2 7,004 — ( 9 ) 6,995 Total short-term investments $ 143,323 $ 2 $ ( 103 ) $ 143,222 Long-term investments: Corporate bonds 2 3,307 — ( 20 ) 3,287 U.S. government debt and agency 2 62,911 — ( 262 ) 62,649 Total long-term investments $ 66,218 $ — $ ( 282 ) $ 65,936 December 31, 2020 Level Amortized Unrealized Unrealized Fair Cash equivalents: Money market fund 1 $ 5 $ — $ — $ 5 Commercial paper 2 44,318 — ( 2 ) 44,316 U.S. government debt and agency 2 4,999 — — 4,999 U.S. treasury bills 2 4,450 — — 4,450 Total cash equivalents $ 53,772 $ — $ ( 2 ) $ 53,770 Short-term investments: Commercial paper 2 77,272 1 ( 4 ) 77,269 U.S. government debt and agency 2 31,835 7 — 31,842 U.S. treasury bills 2 14,029 — ( 3 ) 14,026 Corporate bonds 2 920 — — 920 Total short-term investments $ 124,056 $ 8 $ ( 7 ) $ 124,057 Long-term investments: U.S. government debt and agency 2 78,924 32 — 78,956 U.S. treasury bills 2 4,551 2 — 4,553 Total long-term investments $ 83,475 $ 34 $ — $ 83,509
Grant Liability
Schedule of Fair Value Liabilities, Activity	The following table presents the activity for the grant liability (in thousands): Year Ended December 31, 2020 Fair value at beginning of period $ 1,036 Change in fair value of grant liability 464 Grant liability settled upon completion of IPO ( 1,500 ) Fair value at end of period $ —
Derivative Liability
Schedule of Fair Value Liabilities, Activity	The following table presents the activity for the derivative liability (in thousands): Year Ended December 31, 2020 Fair value at beginning of period $ 999 Derivative liability recorded upon issuance of 774 Change in fair value of derivative liability 132 Derivative liability settled upon conversion of ( 1,905 ) Fair value at end of period $ —
Convertible Preferred Stock Warrant Liability
Schedule of Fair Value Liabilities, Activity	The following table presents the activity for the convertible preferred stock warrant liability (in thousands): Year Ended December 31, 2020 Fair value at beginning of period $ — Recognition of convertible preferred stock 364 Change in fair value 641 Settlement upon IPO ( 1,005 ) Fair value at end of period $ —

Property and Equipment, Net (Ta

Property and Equipment, Net (Tables)	12 Months Ended
	Dec. 31, 2021
Property Plant And Equipment [Abstract]
Schedule of Property and Equipment	Property and equipment consisted of the following (in thousands): December 31, 2021 2020 Lab equipment $ 268 $ 81 Office furniture, fixtures, and 325 — Leasehold improvement 2,563 — Construction in progress 1,124 2,639 Property and equipment, at cost 4,280 2,720 Less: accumulated depreciation ( 523 ) ( 71 ) Property and equipment, net $ 3,757 $ 2,649

Accrued Liabilities (Tables)

Accrued Liabilities (Tables)	12 Months Ended
	Dec. 31, 2021
Payables And Accruals [Abstract]
Schedule of Accrued Liabilities	Accrued liabilities consisted of the following (in thousands): December 31, 2021 2020 Research and development expenses $ 5,723 $ 1,169 Employee compensation and benefits 1,907 1,624 Professional services and other 807 330 Total accrued liabilities $ 8,437 $ 3,123

Other Income (Expense), Net (Ta

Other Income (Expense), Net (Tables)	12 Months Ended
	Dec. 31, 2021
Other Income And Expenses [Abstract]
Schedule of Other Income (Expense), Net	Other income (expense), net consisted of the following (in thousands): Year Ended December 31, 2021 2020 Interest and other income $ 337 $ 124 Interest expense ( 3 ) ( 367 ) Change in fair value of derivative liability — ( 132 ) Change in fair value of grant liability — ( 464 ) Change in convertible preferred stock — ( 641 ) Gain on extinguishment of convertible notes — 199 Total other income (expense), net $ 334 $ ( 1,281 )

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2021
Commitments And Contingencies Disclosure [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): December 31, 2022 452 2023 466 2024 480 2025 494 Thereafter 856 Total undiscounted lease payments 2,748 Present value adjustment for minimum lease ( 548 ) Tenant improvement allowance receivable ( 280 ) Net lease liability $ 1,920
Weighted Average Remaining Lease Term and Weighted Average Discount Rate to Determine the Operating Lease Liability	The weighted average remaining lease term and the weighted average discount rate used to determine the operating lease liability were as follows: December 31, Weighted average remaining lease term (years) 5.9 Weighted average discount rate 8.1 %

Common Stock (Tables)

Common Stock (Tables)	12 Months Ended
	Dec. 31, 2021
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: December 31, 2021 2020 Shares issuable upon the exercise of outstanding 2,632,396 1,974,870 Shares available for future grant under the 2020 4,442,315 3,742,235 Shares available for future grant under the 621,211 323,000 Total 7,695,922 6,040,105

Stock-based Compensation (Table

Stock-based Compensation (Tables)	12 Months Ended
	Dec. 31, 2021
Stock-based Compensation Expense Recognized	Stock‑based compensation expense recognized was as follows (in thousands): Year Ended December 31, 2021 2020 Research and development $ 1,368 $ 215 General and administrative 3,255 418 Total stock-based compensation expense $ 4,623 $ 633
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: Year Ended December 31, 2021 2020 Risk-free interest rate 0.99 % 0.49 % Expected volatility 90.91 % 87.41 % Expected term (in years) 6.10 6.87 Expected dividend yield — —
Summary of Option Activity Changes in Shares Available for Grant under the 2020 Plan	Changes in shares available for grant under the 2020 Plan during the year ended December 31, 2021 were as follows: Shares Shares available for grant at December 31, 2020 3,742,235 2020 Plan reserve increase on January 1, 2021 1,624,259 Options and restricted stock units granted ( 1,392,928 ) Options and restricted stock units forfeited, 468,749 Shares available for grant at December 31, 2021 4,442,315
Summary of Option Activity	A summary of option activity for the year ended December 31, 2021 was as follows: Shares Weighted- Weighted- Aggregate Balance at December 31, 2020 1,974,870 $ 9.31 7.98 $ 49,275 Granted 1,024,776 18.83 Exercised ( 263,501 ) 1.24 Forfeited/expired ( 465,249 ) 18.02 Balance at December 31, 2021 2,270,896 $ 12.76 7.22 $ 8,306 Expected to vest 1,457,586 $ 16.08 8.98 $ 1,925 Options exercisable 813,310 $ 6.80 4.05 $ 6,380
Summary of Stock Options Outstanding and Exercisable	Stock options outstanding and exercisable consisted of the following at December 31, 2021: Employees and Directors Non-employees Exercise Price ($) Shares Shares Shares Shares 0.16 to 1.00 209,780 209,780 — — 1.04 to 1.49 364,524 222,659 113,642 93,150 17.00 to 19.94 989,576 210,071 195,453 60,684 20.55 to 29.41 397,921 16,966 — — Total 1,961,801 659,476 309,095 153,834
Restricted Stock Award (RSA)
Summary of Restricted Stock Activity	A summary of RSA activity for the year ended December 31, 2021 was as follows: Share Weighted- Non-vested at December 31, 2020 4,204 $ 1.35 Granted — — Vested ( 4,204 ) 1.35 Non-vested at December 31, 2021 — $ —
Restricted Stock Units (RSUs)
Summary of Restricted Stock Activity	A summary of RSU activity for the year ended December 31, 2021 is as follows: Share Weighted- Non-vested at December 31, 2020 — $ — Granted 368,152 15.37 Cancelled ( 3,500 ) 15.34 Vested ( 3,152 ) 21.15 Non-vested at December, 2021 361,500 $ 15.32

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2021
Income Tax Disclosure [Abstract]
Components of Income (Loss) Before Income Tax	The Company did not record a provision (benefit) for income taxes for the years ended December 31, 2021 and 2020. Net loss is attributable to the following tax jurisdictions (in thousands): Year Ended December 31, 2021 2020 United States $ ( 54,963 ) $ ( 19,969 ) Foreign 110 14 Net Loss $ ( 54,853 ) $ ( 19,955 )
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, 2021 2020 Federal statutory income tax rate 21.0 % 21.0 % State Taxes 1.2 — Non-deductible expenses and others 0.2 0.2 Non-deductible expense related to the — ( 1.0 ) Non-deductible expense related to the grant — ( 0.1 ) Tax credits 2.2 1.5 Change in valuation allowance ( 24.6 ) ( 21.6 ) Effective income tax rate — % — %
Components of Deferred Tax Assets and Liabilities	The components of the Company’s deferred tax assets and liabilities were as follows (in thousands): Year Ended December 31, 2021 2020 Deferred tax assets: Net operating loss carryforwards $ 19,543 $ 8,090 Research and development tax credit 2,166 1,011 Accrued liabilities 392 295 Stock-based compensation 804 106 Operating lease liability 426 210 Other 224 72 Total deferred tax assets 23,555 9,784 Deferred tax liabilities: Right of use asset ( 324 ) ( 197 ) Prepaid expenses and other ( 664 ) ( 489 ) Total deferred tax liabilities ( 988 ) ( 686 ) Less valuation allowance ( 22,567 ) ( 9,098 ) Net deferred tax assets $ — $ —
Schedule of Unrecognized Tax Benefits for Uncertain Tax Positions	A reconciliation of the beginning and ending amount of unrecognized tax benefits for uncertain tax positions were as follows (in thousands): Year Ended December 31, 2021 2020 Beginning balance $ 337 $ 239 Additions for tax positions taken in the current 385 98 Ending balance $ 722 $ 337

Net Loss Per Share Attributab_2

Net Loss Per Share Attributable to Common Stockholders (Tables)	12 Months Ended
	Dec. 31, 2021
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: Year Ended December 31, 2021 2020 Non-vested RSAs — 4,204 Non-vested RSUs 361,500 — Stock options to purchase common stock 2,270,896 1,974,870 Employee stock purchase plan 1,277 3,995 Total 2,633,673 1,983,069

Immaterial Error Correction (_2

Immaterial Error Correction (Unaudited) (Tables)	12 Months Ended
	Dec. 31, 2021
Prior Period Adjustment [Abstract]
Summary of Immaterial Error Correction	The impact of the error was as follows: Six Months Ended June 30, 2021 As Reported Adjustment As Adjusted Weighted average shares outstanding, 33,813,104 2,685,900 36,499,004 Net loss per share, basic $ ( 0.68 ) $ 0.05 $ ( 0.63 ) Nine Months Ended September 30, 2021 As Reported Adjustment As Adjusted Weighted average shares outstanding, 34,315,047 2,458,053 36,773,100 Net loss per share, basic $ ( 1.12 ) $ 0.07 $ ( 1.05 )

Description of Business - Addit

Description of Business - Additional Information (Details)	Oct. 16, 2020USD ($)$ / sharesshares	Sep. 22, 2020USD ($)$ / sharesshares	Sep. 16, 2020USD ($)shares	Sep. 11, 2020	Feb. 28, 2021USD ($)$ / sharesshares	Jan. 31, 2021USD ($)$ / sharesshares	Dec. 31, 2021USD ($)	Dec. 31, 2020USD ($)	Sep. 23, 2020shares	Dec. 31, 2019shares
Description Of Business [Line Items]
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.
Entity incorporation, date of Incorporation							Mar. 31, 2011
Entity reincorporation, date of reincorporation							Oct. 27, 2015
Reverse stock split conversion ratio				0.1261
Proceeds from public offering, net of issuance costs							$ 96,762,000	$ 208,517,000
Loss on final re-measurement of fair value of warrant liability								$ 641,000
Net cash proceeds from issuance of convertible preferred stock, common stock warrants, and convertible notes							407,400,000
Cash, cash equivalents, and investments							$ 319,700,000
Underwriters’ Option
Description Of Business [Line Items]
Number of shares issued and sold | shares	1,397,712				600,000
Public offering price per share | $ / shares	$ 17				$ 22.50
Net proceeds from public offering					$ 12,700,000
Proceeds from public offering, net of issuance costs	$ 22.1
Follow-on Public Offering
Description Of Business [Line Items]
Number of shares issued and sold | shares						4,000,000
Public offering price per share | $ / shares						$ 22.50
Net proceeds from public offering						$ 84,100,000
IPO
Description Of Business [Line Items]
Number of shares issued and sold | shares		12,000,000
Public offering price per share | $ / shares		$ 17
Proceeds from public offering, net of issuance costs		$ 186.4
Convertible Preferred Stock
Description Of Business [Line Items]
Convertible preferred stock, shares outstanding | shares										2,617,386
Convertible Preferred Stock | IPO
Description Of Business [Line Items]
Common shares issued on conversion of convertible preferred stock | shares		12,503,009
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			$ 600,000
Convertible Preferred Stock, Common Stock Warrants Or Series B Convertible Preferred Stock Warrants
Description Of Business [Line Items]
Convertible preferred stock, shares outstanding | shares									0

Significant Accounting Polici_4

Significant Accounting Policies - Additional Information (Details)	1 Months Ended		12 Months Ended
	Mar. 31, 2021USD ($)	Dec. 31, 2020USD ($)	Dec. 31, 2021USD ($)Segment	Dec. 31, 2020USD ($)	Dec. 31, 2019USD ($)	Jan. 31, 2019USD ($)
Basis Of Presentation And Significant Accounting Policies [Line Items]
Impairment losses			$ 0	$ 0
Grant liability		$ 1,500,000		1,500,000
Number of operating segments | Segment			1
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
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
National Institutes of Health Grant
Basis Of Presentation And Significant Accounting Policies [Line Items]
Grants received			$ 7,600,000
Alzheimers Association
Basis Of Presentation And Significant Accounting Policies [Line Items]
Research grant awarded						$ 1,000,000
Grants received	$ 224,000				$ 776,000
National Institute on Aging of the National Institutes of Health
Basis Of Presentation And Significant Accounting Policies [Line Items]
Research grant awarded		15,200,000		$ 15,200,000
Grants received		7,800,000
Remaining grant to be received		$ 7,400,000
Minimum
Basis Of Presentation And Significant Accounting Policies [Line Items]
Property and equipment useful life			3 years
Maximum
Basis Of Presentation And Significant Accounting Policies [Line Items]
Property and equipment useful life			5 years

Significant Accounting Polici_5

Significant Accounting Policies - Summary of Grant Income in Accompanying Statements of Operations and Comprehensive Loss (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Basis Of Presentation And Significant Accounting Policies [Line Items]
Grant income	$ 8,835	$ 1,321
Alzheimer's Association Part the Cloud Research Grant
Basis Of Presentation And Significant Accounting Policies [Line Items]
Grant income		245
National Institutes of Health Grant
Basis Of Presentation And Significant Accounting Policies [Line Items]
Grant income	$ 8,835	$ 1,076

Significant Accounting Polici_6

Significant Accounting Policies - Summary of Amounts Recorded in the Accompanying Balance Sheets as Unbilled Grant Receivables from the Granting Agencies (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Basis Of Presentation And Significant Accounting Policies [Line Items]
Unbilled grant receivable	$ 2,336	$ 1,300
Alzheimer's Association Part the Cloud Research Grant
Basis Of Presentation And Significant Accounting Policies [Line Items]
Unbilled grant receivable		224
National Institutes of Health Grant
Basis Of Presentation And Significant Accounting Policies [Line Items]
Unbilled grant receivable	$ 2,336	$ 1,076

Fair Value - Schedule of Fair V

Fair Value - Schedule of Fair Value of Cash Equivalents, Short-term Investments and Long-term Investments (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Cash equivalents, Amortized Cost	$ 110,537	$ 60,625
Recurring Basis | Cash Equivalents
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Cash equivalents, Amortized Cost	96,177	53,772
Cash equivalents, Unrealized Losses	(5)	(2)
Cash equivalents, Fair Value	96,172	53,770
Recurring Basis | Cash Equivalents | Money Market Fund | Level 1
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Cash equivalents, Amortized Cost	57	5
Cash equivalents, Fair Value	57	5
Recurring Basis | Cash Equivalents | Commercial Paper | Level 2
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Cash equivalents, Amortized Cost	96,120	44,318
Cash equivalents, Unrealized Losses	(5)	(2)
Cash equivalents, Fair Value	96,115	44,316
Recurring Basis | Cash Equivalents | U.S. Government Debt, Municipal Bonds, and Agency Securities | Level 2
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Cash equivalents, Amortized Cost		4,999
Cash equivalents, Fair Value		4,999
Recurring Basis | Cash Equivalents | U.S. Treasury Bills | Level 2
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Cash equivalents, Amortized Cost		4,450
Cash equivalents, Fair Value		4,450
Recurring Basis | Short-term Investments
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Investments, Amortized Cost	143,323	124,056
Investments, Unrealized Gains	2	8
Investments, Unrealized Losses	(103)	(7)
Investments, Fair Value	143,222	124,057
Recurring Basis | Short-term Investments | Commercial Paper | Level 2
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Investments, Amortized Cost	74,170	77,272
Investments, Unrealized Gains		1
Investments, Unrealized Losses	(35)	(4)
Investments, Fair Value	74,135	77,269
Recurring Basis | Short-term Investments | U.S. Government Debt, Municipal Bonds, and Agency Securities | Level 2
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Investments, Amortized Cost	62,149	31,835
Investments, Unrealized Gains	2	7
Investments, Unrealized Losses	(59)
Investments, Fair Value	62,092	31,842
Recurring Basis | Short-term Investments | Corporate Bonds | Level 2
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Investments, Amortized Cost	7,004	920
Investments, Unrealized Losses	(9)
Investments, Fair Value	6,995	920
Recurring Basis | Short-term Investments | U.S. Treasury Bills | Level 2
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Investments, Amortized Cost		14,029
Investments, Unrealized Losses		(3)
Investments, Fair Value		14,026
Recurring Basis | Long Term Investments
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Investments, Amortized Cost	66,218	83,475
Investments, Unrealized Gains		34
Investments, Unrealized Losses	(282)
Investments, Fair Value	65,936	83,509
Recurring Basis | Long Term Investments | U.S. Government Debt, Municipal Bonds, and Agency Securities | Level 2
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Investments, Amortized Cost	62,911	78,924
Investments, Unrealized Gains		32
Investments, Unrealized Losses	(262)
Investments, Fair Value	62,649	78,956
Recurring Basis | Long Term Investments | Corporate Bonds | Level 2
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Investments, Amortized Cost	3,307
Investments, Unrealized Losses	(20)
Investments, Fair Value	$ 3,287
Recurring Basis | Long Term Investments | U.S. Treasury Bills | Level 2
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Investments, Amortized Cost		4,551
Investments, Unrealized Gains		2
Investments, Fair Value		$ 4,553

Fair Value - Additional Informa

Fair Value - Additional Information (Details) - USD ($)	3 Months Ended	12 Months Ended
	Sep. 30, 2020	Dec. 31, 2021	Dec. 31, 2020	Sep. 22, 2020	Dec. 31, 2019
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		$ 464,000
Total grant liability	$ 1,500,000				$ 1,036,000
Recurring Basis | Minimum
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Long-term investments effective maturity date		1 year
Recurring Basis | Maximum
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Short-term investments effective maturity date		1 year
Long-term investments effective maturity date		2 years

Fair Value - Schedule of Fair_2

Fair Value - Schedule of Fair Value Liabilities, Activity for Grant Liability (Details) - Grant Liability - USD ($)	3 Months Ended	12 Months Ended
	Sep. 30, 2020	Dec. 31, 2020
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Fair value at beginning of period		$ 1,036,000
Change in fair value of liability	$ 464,000	464,000
Settlement upon IPO		$ (1,500,000)
Fair value at end of period	$ 1,500,000

Fair Value - Schedule of Fair_3

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

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	12 Months Ended
	Dec. 31, 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 upon IPO	$ (1,005)

Property and Equipment, Net - S

Property and Equipment, Net - Schedule of Property and Equipment (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Property Plant And Equipment [Line Items]
Property and equipment, at cost	$ 4,280	$ 2,720
Less: accumulated depreciation	(523)	(71)
Property and equipment, net	3,757	2,649
Lab Equipment
Property Plant And Equipment [Line Items]
Property and equipment, at cost	268	81
Office Furniture, Fixtures, and Computer Equipment
Property Plant And Equipment [Line Items]
Property and equipment, at cost	325
Leasehold Improvement
Property Plant And Equipment [Line Items]
Property and equipment, at cost	2,563
Construction in Progress
Property Plant And Equipment [Line Items]
Property and equipment, at cost	$ 1,124	$ 2,639

Property and Equipment, Net - A

Property and Equipment, Net - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Property Plant And Equipment [Abstract]
Depreciation expense	$ 479,000	$ 2,000

Accrued Liabilities - Schedule

Accrued Liabilities - Schedule of Accrued Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Payables And Accruals [Abstract]
Research and development expenses	$ 5,723	$ 1,169
Employee compensation and benefits	1,907	1,624
Professional services and other	807	330
Total accrued Liabilities	$ 8,437	$ 3,123

Other Income (Expense), Net - S

Other Income (Expense), Net - Schedule of Other Income (Expense), Net (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Other Income And Expenses [Abstract]
Interest and other income	$ 337	$ 124
Interest expense	(3)	(367)
Change in fair value of derivative liability		(132)
Change in fair value of grant liability		(464)
Change in convertible preferred stock warrant liability		(641)
Gain on extinguishment of convertible notes		199
Total other income (expense), net	$ 334	$ (1,281)

Significant Agreements - Additi

Significant Agreements - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2015	Dec. 31, 2014	Sep. 30, 2020
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Change in fair value of grant liability		$ 464,000
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
Washington State University License Agreement | Licensed Products
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Sales	$ 0
Washington State University License Agreement | Phase 2 Clinical Trial Initiation
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
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
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		$ 464,000

Convertible Notes - Additional

Convertible Notes - Additional Information (Details) - USD ($)	1 Months Ended	12 Months Ended
	May 31, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Gain on extinguishment of debt			$ 199,000
Unsecured Convertible Notes
Debt Instrument [Line Items]
Debt instrument, principal amount			$ 1,700,000	$ 900,000	$ 1,300,000
Debt instrument, interest rate		5.00%
Debt instrument, maturity month and year		2021-12
Debt instrument, payment terms		No principal or interest was payable prior to maturity as the convertible notes and any accrued interest would 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%
Debt instrument, repurchase price, percentage		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 | Series B-1 Convertible Preferred Stock
Debt Instrument [Line Items]
Debt conversion, converted instrument, shares issued	512,858

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Details)	12 Months Ended
	Dec. 31, 2021USD ($)
Commitments And Contingencies [Line Items]
Operating lease expense	$ 323,000
Variable lease expense	$ 108,000
Wang V. Athira Pharma Inc.,
Commitments And Contingencies [Line Items]
Lawsuit filing date	June 25, 2021
Name of plaintiff	Fan Wang and Hang Gao
Jawandha V. Athira Pharma Inc.,
Commitments And Contingencies [Line Items]
Lawsuit filing date	June 25, 2021
Name of plaintiff	Harshdeep Jawandha
Slyne V. Athira Pharma Inc.,
Commitments And Contingencies [Line Items]
Lawsuit filing date	June 25, 2021
Name of plaintiff	Timothy Slyne and Tai Slyne
Laboratory and Office Facilities | Bothell, Washington
Commitments And Contingencies [Line Items]
Operating lease expiration month and year	2027-08
Operating lease existence of option to extend	true
Operating lease, additional term of contract	5 years
Laboratory and Office Facilities | Bothell, Washington | Minimum
Commitments And Contingencies [Line Items]
Operating lease initial term	6 years 3 months 18 days
Laboratory and Office Facilities | Bothell, Washington | Maximum
Commitments And Contingencies [Line Items]
Operating lease initial term	7 years

Commitments and Contingencies_2

Commitments and Contingencies - Reconciliation of Undiscounted Operating Lease Cash Flows to Operating Lease Liability Payments (Details) $ in Thousands	Dec. 31, 2021USD ($)
Commitments And Contingencies Disclosure [Abstract]
2022	$ 452
2023	466
2024	480
2025	494
Thereafter	856
Total undiscounted lease payments	2,748
Present value adjustment for minimum lease commitments	(548)
Tenant improvement allowance receivable	280
Net lease liability	$ 1,920

Commitments and Contingencies_3

Commitments and Contingencies - Weighted Average Remaining Lease Term and Weighted Average Discount Rate to Determine the Operating Lease Liability (Details)	Dec. 31, 2021
Commitments And Contingencies Disclosure [Abstract]
Weighted average remaining lease term (years)	5 years 10 months 24 days
Weighted average discount rate	8.10%

Convertible Preferred Stock - A

Convertible Preferred Stock - Additional Information (Details) - USD ($)	2 Months Ended	12 Months Ended
	Jun. 30, 2020	Dec. 31, 2020	Sep. 30, 2020
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).
Common Stock | IPO
Class Of Stock [Line Items]
Convertible preferred stock shares issued upon conversion			12,503,009
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
Class of warrant or right, exercise price	$ 9.12
Series B-1 Convertible Preferred Stock
Class Of Stock [Line Items]
Class of warrant or right, 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	Dec. 31, 2021	Dec. 31, 2020
Class Of Stock [Line Items]
Reserved shares of common stock for future issuance	7,695,922	6,040,105
Shares Issuable Upon the Exercise of Outstanding Common Stock Options and the Vesting of Outstanding Common Restricted Stock Units Granted
Class Of Stock [Line Items]
Reserved shares of common stock for future issuance	2,632,396	1,974,870
Shares available for Future Grant under 2020 Equity Incentive Plan
Class Of Stock [Line Items]
Reserved shares of common stock for future issuance	4,442,315	3,742,235
Shares available for Future Grant under Employee Stock Purchase Plan
Class Of Stock [Line Items]
Reserved shares of common stock for future issuance	621,211	323,000

Common Stock - Additional Infor

Common Stock - Additional Information (Details) - shares	12 Months Ended
	Dec. 31, 2021	Jan. 01, 2022	Dec. 31, 2020
Class Of Stock [Line Items]
Reserved shares of common stock for future issuance	7,695,922		6,040,105
Common Stock
Class Of Stock [Line Items]
Issued common stock, share under employee stock purchase plan	26,640
2020 Equity Incentive Plan
Class Of Stock [Line Items]
Share based compensation maximum annual increase in number of shares that may be issued under the plan	3,230,000
Share based compensation percentage of number shares of common stock issued and outstanding on immediate proceeding	5.00%
Reserved shares of common stock for future issuance	1,624,259
2020 Equity Incentive Plan | Subsequent Event
Class Of Stock [Line Items]
Reserved shares of common stock for future issuance		1,868,953
2020 Employee Stock Purchase Plan
Class Of Stock [Line Items]
Share based compensation maximum annual increase in number of shares that may be issued under the plan	646,000
Share based compensation percentage of number shares of common stock issued and outstanding on immediate proceeding	1.00%
Reserved shares of common stock for future issuance	324,851
2020 Employee Stock Purchase Plan | Subsequent Event
Class Of Stock [Line Items]
Reserved shares of common stock for future issuance		373,790

Stock-based Compensation - Stoc

Stock-based Compensation - Stock-based Compensation Expense Recognized (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 4,623	$ 633
Research and Development
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	1,368	215
General and Administrative
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 3,255	$ 418

Stock-based Compensation - Addi

Stock-based Compensation - Additional Information (Details) - USD ($)	Jan. 01, 2021	Nov. 30, 2021	Sep. 30, 2020	Dec. 31, 2021	Dec. 31, 2020	Jan. 01, 2022
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected dividend yield				0.00%
Weighted-average grant-date fair value of options granted				$ 14,400,000	$ 4,200,000
Weighted-average grant-date fair value of restricted stock units granted				5,700,000	0
Fair value of options vested				1,400,000	271,000
Aggregate intrinsic value of options exercised				3,100,000	$ 18,000,000
Unrecognized compensation cost				$ 10,200,000
Remaining weighted-average period expected to recognize unrecognized compensation cost				1 year 6 months 7 days
Reserved shares of common stock for future issuance				7,695,922	6,040,105
Common stock available for future grants				4,442,315	3,742,235
Stock-based compensation expense				$ 4,623,000	$ 633,000
Common Stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Issued common stock, share under employee stock purchase plan				26,640
2020 Employee Stock Purchase Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Offering periods			6 months
Percentage of fair market value of common shares	1.00%		85.00%
Reserved shares of common stock for future issuance				621,211
Terms of award				Under the ESPP, eligible employees can authorize payroll deductions for amounts up to the lesser of 15% of their qualifying wages or the statutory limit under the U.S. Internal Revenue Code. The ESPP provides for offering periods of six months in duration with one purchase period per offering period beginning May 18 and November 18 of each year.
Stock-based compensation expense				$ 164,000	$ 46,000
2020 Employee Stock Purchase Plan | Subsequent Event
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock available for future grants						373,790
2020 Employee Stock Purchase Plan | Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Maximum percentage of payroll deductions for qualifying wages or statutory limit			15.00%
Shares of common stock purchased by each participant				5,000
Common stock available for future grants	646,000
Restricted Stock Award (RSA)
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting period				3 years
Granted, shares		365,000
Fair value of options granted		$ 5,600,000
Restricted Stock Units (RSUs)
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Remaining weighted-average period expected to recognize unrecognized compensation cost				1 year 3 months 29 days
Granted, shares				368,152
Unrecognized stock-based compensation expense related to non-vested restricted stock units				$ 4,800,000
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

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)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Risk-free interest rate	0.99%	0.49%
Expected volatility	90.91%	87.41%
Expected term (in years)	6 years 1 month 6 days	6 years 10 months 13 days
Expected dividend yield	0.00%

Stock-based Compensation - Summ

Stock-based Compensation - Summary of Option Activity Changes in Shares Available for Grant under the 2020 Plan (Details)	12 Months Ended
	Dec. 31, 2021shares
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Available for Grant, Beginning Balance	3,742,235
2020 Plan reserve increase on January 1, 2021	1,624,259
Options and restricted stock units granted	(1,392,928)
Options and restricted stock units forfeited, cancelled, or expired	468,749
Available for Grant, Ending Balance	4,442,315

Stock-based Compensation - Su_2

Stock-based Compensation - Summary of Option Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Shares, Beginning Balance	1,974,870
Shares, Granted	1,024,776
Shares, Exercised	(263,501)
Shares, Forfeited/expired	(465,249)
Shares, Ending Balance	2,270,896	1,974,870
Shares, Expected to vest	1,457,586
Shares, Options exercisable	813,310
Weighted-Average Exercise price per Share, Beginning Balance	$ 9.31
Weighted-Average Exercise price per Share, Granted	18.83
Weighted-Average Exercise price per Share, Exercised	1.24
Weighted-Average Exercise price per Share, Forfeited/expired	18.02
Weighted-Average Exercise price per Share, Ending Balance	12.76	$ 9.31
Weighted-Average Exercise price per Share, Expected to vest	16.08
Weighted-Average Exercise price per Share, Options exercisable	$ 6.80
Weighted-Average Remaining Contractual Term (in years)	7 years 2 months 19 days	7 years 11 months 23 days
Weighted-Average Remaining Contractual Term, Expected to vest (in years)	8 years 11 months 23 days
Weighted-Average Remaining Contractual Term, Options exercisable (in years)	4 years 18 days
Aggregate Intrinsic Value, Outstanding Balance	$ 8,306	$ 49,275
Aggregate Intrinsic Value, Expected to vest	1,925
Aggregate Intrinsic Value, Options exercisable	$ 6,380

Stock-based Compensation - Su_3

Stock-based Compensation - Summary of Stock Options Outstanding and Exercisable (Details) - $ / shares	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Shares Outstanding	2,270,896	1,974,870
Shares Exercisable	813,310
Employees and Directors
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Shares Outstanding	1,961,801
Shares Exercisable	659,476
Non-employees
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Shares Outstanding	309,095
Shares Exercisable	153,834
Exercise Price $0.16 to 1.00 | Employees and Directors
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Shares Outstanding	209,780
Shares Exercisable	209,780
Exercise Price $0.16 to 1.00 | Minimum
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Exercise Price ($)	$ 0.16
Exercise Price $0.16 to 1.00 | Maximum
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Exercise Price ($)	$ 1
Exercise Price $1.04 to 1.49 | Employees and Directors
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Shares Outstanding	364,524
Shares Exercisable	222,659
Exercise Price $1.04 to 1.49 | Non-employees
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Shares Outstanding	113,642
Shares Exercisable	93,150
Exercise Price $1.04 to 1.49 | Minimum
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Exercise Price ($)	$ 1.04
Exercise Price $1.04 to 1.49 | Maximum
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Exercise Price ($)	$ 1.49
Exercise Price $17.00 to 19.94 | Employees and Directors
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Shares Outstanding	989,576
Shares Exercisable	210,071
Exercise Price $17.00 to 19.94 | Non-employees
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Shares Outstanding	195,453
Shares Exercisable	60,684
Exercise Price $17.00 to 19.94 | Minimum
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Exercise Price ($)	$ 17
Exercise Price $17.00 to 19.94 | Maximum
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Exercise Price ($)	$ 19.94
Exercise Price $20.55 to 29.41 | Employees and Directors
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Shares Outstanding	397,921
Shares Exercisable	16,966
Exercise Price $20.55 to 29.41 | Minimum
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Exercise Price ($)	$ 20.55
Exercise Price $20.55 to 29.41 | Maximum
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Exercise Price ($)	$ 29.41

Stock-based Compensation - Su_4

Stock-based Compensation - Summary of Restricted Stock Activity (Details) - $ / shares	1 Months Ended	12 Months Ended
	Nov. 30, 2021	Dec. 31, 2021
Restricted Stock Award (RSA)
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share Equivalent, Non-vested, Beginning Balance		4,204
Share Equivalent, Granted	365,000
Share Equivalent, Vested		(4,204)
Weighted-Average Grant Date Fair Value, Non-vested, Beginning Balance		$ 1.35
Weighted-Average Grant Date Fair Value, Non-vested, Vested		$ 1.35
Restricted Stock Units (RSUs)
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share Equivalent, Granted		368,152
Share Equivalent, Cancelled		(3,500)
Share Equivalent, Vested		(3,152)
Share Equivalent, Non-vested, Ending Balance		361,500
Weighted-Average Grant Date Fair Value, Non-vested, Granted		$ 15.37
Weighted-Average Grant Date Fair Value, Non-vested, Cancelled		15.34
Weighted-Average Grant Date Fair Value, Non-vested, Vested		21.15
Weighted-Average Grant Date Fair Value, Non-vested, Ending Balance		$ 15.32

Income Taxes - Components of In

Income Taxes - Components of Income (Loss) Before Income Tax (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Income Tax Disclosure [Abstract]
United States	$ (54,963)	$ (19,969)
Foreign	110	14
Net loss	$ (54,853)	$ (19,955)

Income Taxes - Schedule of Effe

Income Taxes - Schedule of Effective Income Tax Rate Reconciliation (Details)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Federal statutory income tax rate	21.00%	21.00%
State Taxes	1.20%
Non-deductible expenses and others	0.20%	0.20%
Non-deductible expense related to the convertible notes and derivative liability		(1.00%)
Non-deductible expense related to the grant liability		(0.10%)
Tax credits	2.20%	1.50%
Change in valuation allowance	(24.60%)	(21.60%)

Income Taxes - Components of De

Income Taxes - Components of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Deferred tax assets:
Net operating loss carryforwards	$ 19,543	$ 8,090
Research and development tax credit carryforwards	2,166	1,011
Accrued liabilities	392	295
Stock-based compensation	804	106
Operating lease liability	426	210
Other	224	72
Total deferred tax assets	23,555	9,784
Deferred tax liabilities:
Right of use asset	(324)	(197)
Prepaid expenses and other	(664)	(489)
Total deferred tax liabilities	(988)	(686)
Less valuation allowance	$ (22,567)	$ (9,098)

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Income Tax Contingency [Line Items]
Change in valuation allowance	$ 13,500,000	$ 4,300,000
Net operating loss carryforwards	80,700,000
Material interest and penalties on uncertain tax benefits	0
Federal
Income Tax Contingency [Line Items]
Net operating loss carryforwards	9,500,000
Tax credit carryforwards	$ 2,900,000
Minimum | Federal
Income Tax Contingency [Line Items]
Net operating loss and tax credit carryforwards, expiration period	10 years
Maximum | Federal
Income Tax Contingency [Line Items]
Net operating loss and tax credit carryforwards, expiration period	16 years

Income Taxes - Schedule of Unre

Income Taxes - Schedule of Unrecognized Tax Benefits for Uncertain Tax Positions (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Beginning balance	$ 337	$ 239
Additions for tax positions taken in the current year	385	98
Ending balance	$ 722	$ 337

Employee Benefit Plans (Details

Employee Benefit Plans (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
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	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
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	2,633,673	1,983,069
Non-Vested 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
Non-vested RSUs
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	361,500
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	2,270,896	1,974,870
Employee Stock Purchase Plan
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	1,277	3,995

Immaterial Error Correction (_3

Immaterial Error Correction (Unaudited) - Summary of Immaterial Errors Correction in the Weighted-Average Number of Common Shares Outstanding (Details) - $ / shares	6 Months Ended	9 Months Ended	12 Months Ended
	Jun. 30, 2021	Sep. 30, 2021	Dec. 31, 2021	Dec. 31, 2020
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Weighted average shares outstanding, basic and diluted	36,499,004	36,773,100	36,921,172	11,966,912
Net loss per share, basic and diluted	$ (0.63)	$ (1.05)	$ (1.49)	$ (1.67)
As Reported
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Weighted average shares outstanding, basic and diluted	33,813,104	34,315,047
Net loss per share, basic and diluted	$ (0.68)	$ (1.12)
Adjusted
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Weighted average shares outstanding, basic and diluted	2,685,900	2,458,053
Net loss per share, basic and diluted	$ 0.05	$ 0.07