0001564590-22-007364 | 10-K | XBRL Viewer | ALX Oncology Holdings INC

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Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 363,667	$ 434,219
Prepaid expenses and other current assets	3,352	1,773
Total current assets	367,019	435,992
Property and equipment, net	897	52
Other assets	12,267	10
Total assets	380,183	436,054
Current liabilities:
Accounts payable	3,764	4
Payable and accrued liabilities due to related party	1,630	72
Accrued expenses and other current liabilities	9,901	6,128
Total current liabilities	15,295	6,204
Other non-current liabilities	1,839	5
Total liabilities	17,134	6,209
Commitments and contingencies (Note 13)
Stockholders’ equity
Common stock, $0.001 par value; 1,000,000,000 shares authorized as of December 31, 2021 and 2020, respectively; 40,587,067 and 39,844,522 shares issued and outstanding as of December 31, 2021 and 2020, respectively	41	40
Additional paid-in capital	564,993	548,327
Accumulated deficit	(201,985)	(118,522)
Total stockholders’ equity	363,049	429,845
Total liabilities and stockholders’ equity	$ 380,183	$ 436,054

Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2021	Dec. 31, 2020
Statement Of Financial Position [Abstract]
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized	1,000,000,000	1,000,000,000
Common stock, shares issued	40,587,067	39,844,522
Common stock, shares outstanding	40,587,067	39,844,522

Consolidated Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Income Statement [Abstract]
Related-party revenue		$ 1,182	$ 4,796
Type of revenue description	Related-party	Related-party	Related-party
Operating expenses:
Research and development	$ 60,170	$ 28,961	$ 16,306
General and administrative	23,385	14,809	3,313
Cost of services for related-party revenue		1,075	4,360
Total operating expenses	83,555	44,845	23,979
Loss from operations	(83,555)	(43,663)	(19,183)
Interest expense	(13)	(811)	(21)
Other income (expense), net	84	(404)	(5)
Loss on early debt extinguishment		(621)
Loss before income taxes	(83,484)	(45,499)	(19,209)
Income tax benefit (provision)	21	(241)	(34)
Net loss and comprehensive loss	(83,463)	(45,740)	(19,243)
Cumulative dividends allocated to preferred stockholders		(5,202)	(4,028)
Net loss attributable to common stockholders	$ (83,463)	$ (50,942)	$ (23,271)
Net loss per share attributable to common stockholders, basic and diluted	$ (2.07)	$ (2.76)	$ (7.56)
Weighted-average shares of common stock used to compute net loss per share attributable to common stockholders, basic and diluted	40,308,050	18,485,343	3,076,461

Consolidated Statements of Convertible Preferred Stock and Stockholders' Equity (Deficit) - USD ($) $ in Thousands	Total	Convertible Preferred Stock	Common Stock	Additional Paid-in Capital	Accumulated Deficit
Balance at Dec. 31, 2018	$ (51,778)		$ 3	$ 1,758	$ (53,539)
Temporary equity, shares at Dec. 31, 2018		9,297,081
Temporary equity, balance at Dec. 31, 2018		$ 60,933
Balance, shares at Dec. 31, 2018			3,161,747
Issuance of convertible preferred stock, net of issuance costs		$ 9,430
Issuance of convertible preferred stock, net of issuance costs, shares		1,016,727
Issuance of common stock under equity incentive plans	10			10
Issuance of common stock under equity incentive plans, shares			5,199
Vesting of early exercised stock options	75			75
Stock-based compensation	297			297
Net loss	(19,243)				(19,243)
Balance at Dec. 31, 2019	(70,639)		$ 3	2,140	(72,782)
Temporary equity, shares at Dec. 31, 2019		10,313,808
Temporary equity, balance at Dec. 31, 2019		$ 70,363
Balance, shares at Dec. 31, 2019			3,166,946
Issuance of convertible preferred stock, net of issuance costs		$ 104,680
Issuance of convertible preferred stock, net of issuance costs, shares		11,055,966
Reclassification of warrants from liability to equity	1,019			1,019
Conversion of convertible preferred stock in to common stock	175,043	$ (175,043)	$ 21	175,022
Conversion of convertible preferred stock into common stock, shares		(21,369,774)	21,369,774
Cumulative dividends			$ 3	(3)
Cumulative dividends, shares			2,564,759
Issuance of common stock in connection with equity offerings, net of underwriter discounts and issuance costs	364,400		$ 13	364,387
Issuance of common stock in connection with equity offerings, net of underwriter discounts and issuance costs, shares			12,512,000
Issuance of common stock upon net exercise of warrants			48,932
Issuance of common stock under equity incentive plans	299			299
Issuance of common stock under equity incentive plans, shares			182,111
Vesting of early exercised stock options	27			27
Stock-based compensation	5,436			5,436
Net loss	(45,740)				(45,740)
Balance at Dec. 31, 2020	429,845		$ 40	548,327	(118,522)
Balance, shares at Dec. 31, 2020			39,844,522
Issuance of common stock under equity incentive plans	2,551		$ 1	2,550
Issuance of common stock under equity incentive plans, shares			734,922
Issuance of common stock under employee stock purchase plan	202			202
Issuance of common stock under employee stock purchase plan, shares			7,623
Stock-based compensation	13,914			13,914
Net loss	(83,463)				(83,463)
Balance at Dec. 31, 2021	$ 363,049		$ 41	$ 564,993	$ (201,985)
Balance, shares at Dec. 31, 2021			40,587,067

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Operating activities
Net loss	$ (83,463)	$ (45,740)	$ (19,243)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	51	202	429
Non-cash lease costs	685
Acquired in-process research and development	4,739
Stock-based compensation	13,914	5,436	297
Amortization of term loan discount and issuance costs		421	11
Changes in fair value of compound derivative liability and warrants		650
Gain on assignment of lease		(126)
Loss on early debt extinguishment		621
Changes in operating assets and liabilities
Receivables due from related-party		536	396
Prepaid expenses and other current assets	(1,662)	(1,514)	744
Other assets	(9,682)	(10)	7
Accounts payable	3,290	(3,744)	2,976
Payable and accrued liabilities due to related party	1,419
Accrued expenses and other current liabilities	3,306	4,983	134
Other non-current liabilities	(698)	(4)
Net cash used in operating activities	(68,101)	(38,289)	(14,249)
Investing activities
Purchase of property and equipment	(666)	(31)	(353)
Acquisition of in-process research and development	(4,257)
Proceeds from assets held for sale		641
Net cash provided by (used in) investing activities	(4,923)	610	(353)
Financing activities
Proceeds from common stock offerings, net		368,256
Payments of offering costs		(3,848)
Proceeds from exercise of stock options under equity incentive plan	2,551	299	10
Proceeds from issuance of common stock pursuant to employee stock purchase plan	202
Proceeds from issuance of convertible preferred stock, net		104,680	9,430
Principal payments on finance leases	(281)
Proceeds from issuance of term loan, net			5,917
Cash paid for early debt extinguishment		(6,506)
Net cash provided by financing activities	2,472	462,881	15,357
Net increase (decrease) in cash and cash equivalents	(70,552)	425,202	755
Cash and cash equivalents at beginning of year	434,219	9,017	8,262
Cash and cash equivalents at end of year	363,667	434,219	9,017
Supplemental disclosure
Cash paid for interest	11	427
Cash paid for taxes	274	47
Supplemental disclosure of non-cash investing and financing activities
Vesting of early exercised stock options		27	75
Purchase of property and equipment in accounts payable and accrued expenses	237	7
Acquisition of in-process research and development in accounts payable and accrued expenses	482
Debt issuance costs in accounts payable			$ 95
Conversion of convertible preferred stock into common stock upon closing of initial public offering		175,043
Accumulated dividend on convertible preferred stock		$ 3
Right-of-use asset acquired under operating leases	1,780
Right-of-use asset acquired under finance leases	$ 776

Organization

12 Months Ended

Dec. 31, 2021

Accounting Policies [Abstract]

ORGANIZATION

(1) ORGANIZATION

Organization

ALX Oncology Holdings Inc., or the Company, was formed as a Delaware corporation on April 1, 2020, or Inception. The Company was formed for the purpose of completing the Company’s initial public offering of its common stock and related transactions in order to carry on the business of ALX Oncology Limited. After Inception, ALX Oncology Limited became a wholly-owned subsidiary of the Company as a result of the internal reorganization. As part of the internal reorganization, all of the equity, option and warrant holders of ALX Oncology Limited became equity, option and warrant holders of the Company, holding the same number of corresponding shares, options and/or warrants in the Company as they did in ALX Oncology Limited immediately prior to the internal reorganization. The information included herein is presented as that of ALX Oncology Holdings Inc. unless such information refers to a date prior to April 1, 2020, in which case it will reflect that of ALX Oncology Limited, the predecessor company. The Company is a clinical-stage immuno-oncology company focused on helping patients fight cancer by developing therapies that block the CD47 checkpoint pathway and bridge the innate and adaptive immune system.

The Company owns subsidiaries, consisting of ALX Oncology Limited, incorporated in Ireland; ALX Oncology Inc., incorporated in the United States, Alexo International Holdings Ltd, incorporated in Malta; ScalmiBio, Inc., incorporated in the United States, Alexo Therapeutics International, incorporated in the Cayman Islands, which is a wholly-owned subsidiary of Alexo International Holdings Ltd., and Sirpant Therapeutics, incorporated in the Cayman Islands, which is a wholly-owned subsidiary of Alexo Therapeutics International, or collectively, the Subsidiaries.

As of December 31, 2021, the Company has devoted substantially all of its efforts to the formation and financing of the Company, as well as product development, and has not realized product revenues from its planned principal operations. The Company has no manufacturing facilities and all manufacturing related activities are contracted out to third-party service providers.

Management expects to incur additional losses in the future to conduct product candidate research and development and to conduct pre-commercialization activities and recognizes that the Company will likely raise additional capital to fully implement its business plan. The Company intends to raise such capital through the sale of additional equity, debt financings or strategic alliances with third parties. However, there can be no assurance that the Company will be successful in acquiring additional funding at levels sufficient to fund its operations or on terms acceptable to the Company. If the Company is unsuccessful in its efforts to raise additional financing, the Company could be required to significantly reduce operating expenses and delay, reduce the scope of or eliminate some of its development programs or its future commercialization efforts, out-license intellectual property rights to its product candidates and sell unsecured assets, or a combination of the above, any of which may have a material adverse effect on the Company’s business, results of operations, financial condition and/or its ability to fund its scheduled obligations on a timely basis or at all. The Company believes that the existing capital resources will be sufficient to fund the projected operating requirements for at least the next twelve months.

Significant Accounting Policies

12 Months Ended

Dec. 31, 2021

Accounting Policies [Abstract]

SIGNIFICANT ACCOUNTING POLICIES

(2) SIGNIFICANT ACCOUNTING POLICIES

Basis of Preparation

These consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America, or U.S. GAAP, and the applicable rules and regulations of the U.S. Securities and Exchange Commission, or SEC.

Reclassifications

Certain reclassifications have also been made within the consolidated balance sheet as of December 31, 2020 to conform to the current year presentation. The Company reclassified approximately $0.1 million out of accrued expenses and other current liabilities into payable and accrued liabilities due to related-party. Total current liabilities as of December 31, 2020 did not change as a result of these reclassifications.

Principles of Consolidation

All intercompany balances and transactions have been eliminated in consolidation.

Reverse Stock Split

On July 8, 2020, the Company’s board of directors approved an amendment to the Company’s certificate of incorporation to effect a 1-for-6.5806 reverse split of its common stock and convertible preferred stock. The par values of the common and convertible preferred stock were not adjusted as a result of the reverse stock split. All authorized, issued and outstanding common stock, convertible preferred stock, stock options, warrants, and related per share amounts contained in the consolidated financial statements have been retroactively adjusted to reflect this reverse stock split for all periods presented. The reverse stock split was effected on July 9, 2020.

Use of Estimates

The preparation of the consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the consolidated financial statements and the reported amounts of revenues and expenses during the reporting periods. On an ongoing basis, management evaluates its estimates, including those related to the estimated useful lives of long-lived assets, clinical trial accruals, fair value of assets and liabilities, Series B convertible preferred stock warrant liability, term loan compound derivative liability, term loan, valuation of the Company’s common stock, income taxes and stock-based compensation. Management bases its estimates on historical experience and on various other market-specific and relevant assumptions that management believes to be reasonable under the circumstances. Actual results could differ from those estimates.

Cash and Cash Equivalents

The Company holds its cash and cash equivalents in checking and money market accounts. The Company considers all highly liquid investments with original maturities of three months or less from the date of purchase to be cash equivalents. Cash equivalents consist primarily of amounts invested in money market accounts that are stated at cost, which approximate fair value.

Concentration of Credit Risk, Credit Losses and Other Risks and Uncertainties

Financial instruments that potentially subject the Company to a concentration of credit risk consist primarily of cash and cash equivalents. The Company maintains deposits in federally insured financial institutions in excess of federally insured limits, and invests in money market funds. The Company is exposed to credit risk in the event of default by the financial institutions holding its cash and cash equivalents. The Company believes that the institutions are financially stable and, accordingly, minimal credit risk exists. The Company has not experienced any losses on its deposits of cash and cash equivalents.

The Company’s future results of operations involve a number of other risks and uncertainties. Factors that could affect the Company’s future operating results and cause actual results to vary materially from expectations include, but are not limited to, uncertainty of results of clinical trials and reaching milestones, uncertainty of regulatory approval of the Company’s potential product candidates, uncertainty of market acceptance of the Company’s product candidates, competition from substitute products and larger companies, securing and protecting proprietary technology, strategic relationships and dependence on key individuals or sole-source suppliers.

The Company’s product candidates require approvals from the U.S. Food and Drug Administration, or FDA, and comparable foreign regulatory agencies prior to commercial sales in their respective jurisdictions. There can be no assurance that any product candidates will receive the necessary approvals. If the Company was denied approval, approval was delayed or the Company was unable to maintain approval for any product candidate, it could have a materially adverse impact on the Company.

Property and Equipment

Property and equipment are stated at cost less accumulated depreciation. Depreciation of property and equipment is provided using the straight-line method over the estimated useful lives of the assets. Leasehold improvements are amortized on a straight-line basis over the shorter of the term of the lease, or the useful life of the assets. Upon sale or retirement of assets, the cost and related accumulated depreciation or amortization are removed from the consolidated balance sheet and the resulting gain or loss is reflected in the consolidated statement of operations and comprehensive loss. Maintenance and repairs are charged to the consolidated statement of operations and comprehensive loss as incurred.

Deferred Offering Costs

The Company capitalizes certain legal, professional accounting and other third-party fees that are directly associated with in-process equity financings as deferred offering costs until such financings are consummated. After consummation of the equity financing, these costs are recorded in stockholders’ equity as a reduction of additional paid-in capital generated as a result of the equity financing.

Leases

On January 1, 2021, the Company adopted Accounting Standards Update No. 2016-02, Leases, Topic 842, or Accounting Standards Codification (ASC) 842, using the alternative modified transition method, which applies the standard as of the adoption date. Results and disclosure requirements for reporting periods beginning after January 1, 2021 are presented under ASC 842, while prior period amounts have not been adjusted and continue to be reported in accordance with the historical accounting under ASC 840.

The Company determines if an arrangement contains a lease at inception. For arrangements where the Company is the lessee, leases are included in operating or finance lease right-of-use, or ROU, assets; current operating or finance lease liabilities; and non-current operating or finance lease liabilities.

Lease ROU assets and lease liabilities are recognized based on the present value of the future minimum lease payments over the lease term at the commencement date. ROU assets also include any initial direct costs incurred and any lease payments made on or before the lease commencement date, less lease incentives received. The Company uses its incremental borrowing rate based on the information available at the commencement date in determining the lease liabilities as the Company’s leases generally do not provide an implicit rate. The incremental borrowing rate is reevaluated upon a lease modification. The Company considered information available at the adoption date of ASC 842 to determine the incremental borrowing rate for leases in existence as of this date. Lease terms may include options to extend or terminate the lease when the Company is reasonably certain that the option will be exercised. Lease expense for operating leases is recognized on a straight-line basis over the lease term. For finance leases, ROU assets are amortized on a straight-line basis over the shorter of the expected useful life or the lease term, and the carrying amount of the lease liability is adjusted to reflect interest, which is recorded in interest expense.

The Company elected to apply each of the practical expedients described in ASC 842 which allow companies (i) not to reassess prior conclusions on whether any expired or existing contracts are or contain a lease, lease classification, and initial direct costs, (ii) combine lease and non-lease components for all underlying assets groups, and (iii) not recognize ROU assets or lease liabilities for short term leases. A short-term lease is a lease that, at the commencement date, has a lease term of 12 months or less and does not include an option to purchase the underlying asset that the lessee is reasonably certain to exercise.

Impairment of Long-Lived Assets

The Company reviews long-lived assets for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset or asset group may not be recoverable. Recoverability is measured by comparison of the carrying amount to the future undiscounted net cash flows which the asset or asset group are expected to generate. If such assets are considered to be impaired, the impairment to be recognized is measured as the amount by which the carrying amount of the assets exceeds its fair value. Fair value is determined using various valuation techniques including discounted cash flow models, quoted market values and third-party independent appraisals, as considered necessary. The Company has not recorded impairment of any long-lived assets.

Fair Value of Financial Instruments

The Company applies fair value accounting for all financial assets and liabilities and nonfinancial assets and liabilities that are required to be recognized or disclosed at fair value in the consolidated financial statements. The Company defines fair value as the price that would be received from selling an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. Where observable prices or inputs are not available valuation models are applied. These valuation techniques involve some level of management estimation and judgment, the degree of which is dependent on the price transparency for the instruments or market and the instruments’ complexity.

Convertible Preferred Stock

The Company records convertible preferred stock net of issuance costs on the dates of issuance, which represents the carrying value. In the event of a change of control of the Company, proceeds will be distributed in accordance with the liquidation preferences set forth in its organization documents unless the holders of convertible preferred stock have converted their convertible preferred stock into common stock. Convertible preferred stock is classified outside of stockholders’ equity (deficit) on the accompanying consolidated balance sheets as events triggering the liquidation preferences are not solely within the Company’s control. The Company has elected not to adjust the carrying values of the convertible preferred stock to the liquidation preferences of such shares because of the uncertainty of whether or when such an event would occur. Upon the consummation of the Company’s initial public offering in July 2020, all shares of convertible preferred stock outstanding and accrued cumulative dividends automatically converted into 23,934,533 shares of common stock.

Series B Convertible Preferred Stock Warrant Liability

The Company has issued freestanding warrants to purchase its Series B convertible preferred stock. Freestanding warrants for the Company’s convertible preferred stock that are classified outside of permanent equity are recorded at fair value, and are subject to re-measurement at the end of every period until the earlier of the exercise of the warrants or the completion of a liquidation event, including the completion of an initial public offering. Upon exercise, the Series B convertible preferred stock warrant liability would be reclassified to additional paid-in capital, with any change in fair value recognized as a component of other expense, net. Following the Company’s initial public offering, the warrants were automatically converted to warrants to purchase shares of common stock. The Company revalued the Series B convertible preferred stock warrants as of the completion of the initial public offering and reclassified the outstanding preferred stock warrant liability balance to additional paid-in capital with no further re-measurement required as common stock warrants are considered permanent equity.

Revenue Recognition

To date, the Company has derived revenue from providing research and development services on a time and materials basis to a related-party.

The Company recognizes such revenues over time as services are delivered, and invoices the customer as the work is incurred in arrears.

The Company recognizes revenue when its customer obtains control of promised goods or services, in an amount that reflects the consideration which the Company expects to receive in exchange for those goods or services.

To determine revenue recognition for arrangements that the Company determines are within the scope of ASC 606, Revenue from Contracts with Customers, the Company performs the following five steps: (i) identify the contract(s) with a customer; (ii) identify the performance obligations in the contract; (iii) determine the transaction price; (iv) allocate the transaction price to the performance obligations in the contract; and (v) recognize revenue when (or as) the Company satisfies a performance obligation.

As part of the Company’s consideration as to whether the Company has entered into a contract with a customer, it considers whether it is probable that it will collect the consideration it is entitled to in exchange for the goods and services it transfers to the customer. At contract inception, the Company assesses the goods or services promised within each contract that falls under the scope of ASC 606, determines those that are performance obligations, and assesses whether each promised good or service is distinct. The Company then recognizes as revenue the amount of the transaction price that is allocated to the respective performance obligation when (or as) the performance obligation is satisfied.

Cost of Services for Related-Party Revenue

The Company incurs costs associated with related-party services including direct labor and associated employee benefits, laboratory supplies, and other expenses. These costs are recorded in cost of services for related-party revenue as a component of total operating expenses in the accompanying consolidated statements of operations and comprehensive loss.

Research and Development Costs

Research and development costs are expensed as incurred and consist primarily of salaries and benefits, stock-based compensation expense, lab supplies and facility costs, as well as fees paid to nonemployees and entities that conduct certain research and development activities on behalf of the Company and expenses incurred in connection with license agreements. Nonrefundable advance payments for goods or services to be received in the future for use in research and development activities are capitalized and recorded in prepaid expenses and other current assets, and then expensed as the related goods are delivered or the services are performed.

Asset Acquisition including Acquired In-Process Research and Development Expenses

When determining whether a transaction gives rise to an acquisition of a business or asset group, the Company applies a screening test to determine whether substantially all of the fair value of the gross assets acquired in the transaction is concentrated in a single identifiable asset or group of similar identifiable assets. If so, then the assets are not considered a business and the transaction is accounted for as an asset acquisition.

The Company measures and recognizes asset acquisitions that are not deemed to be business combinations based on the cost to acquire the asset or group of assets, which includes transaction costs. Goodwill is not recognized in asset acquisitions or transactions to license intellectual property. In an asset acquisition, the cost allocated to acquired in-process research and development (IPR&D) with no alternative future use is recognized as an expense on the acquisition date.

When a transaction is accounted for as an asset acquisition, an in-process research and development, or IPR&D asset is only capitalized if it has an alternative future use other than in a particular research and development project. Otherwise, amounts allocated to IPR&D that have no alternative use are expensed.

Upfront and milestone payments made related to an asset acquisition are accrued for and expensed when the achievement of the milestone is considered probable.

Clinical and Manufacturing Accruals

The Company records accruals for estimated costs of research, preclinical studies and clinical trials, and manufacturing development, which are a significant component of research and development expenses. A substantial portion of the Company’s ongoing research and development activities are conducted by third-party service providers, including contract research organizations, or CROs, and contract manufacturing organizations, or CMOs. The Company’s contracts with CROs generally include pass-through fees such as regulatory expenses, investigator fees, travel costs and other miscellaneous costs, including shipping and printing fees. The financial terms of these contracts are subject to negotiations, which vary from contract to contract and may result in payment flows that do not match the periods over which materials or services are provided to the Company under such contracts. The Company accrues the costs incurred under agreements with these third parties based on estimates of actual work completed in accordance with the respective agreements. The Company determines the estimated costs through discussions with internal personnel and external service providers as to the progress or stage of completion of the services and the agreed-upon fees to be paid for such services.

The Company makes significant judgments and estimates in determining the accrual balance at the end of each reporting period. As actual costs become known, the Company adjusts its accruals. Although the Company does not expect its estimates to be materially different from amounts actually incurred, the Company’s understanding of the status and timing of services performed relative to the actual status and timing of services performed may vary and could result in the Company reporting amounts that are too high or too low in any particular period. To assist in its estimates the Company relies upon the receipt of timely and accurate reporting

from its clinical and non-clinical studies and other third-party vendors. Through December 31, 2021, there have been no material differences from the Company’s accrued estimated expenses to the actual clinical trial expenses. However, variations in the assumptions used to estimate accruals, including, but not limited to, the number of patients enrolled, the rate of patient enrollment, and the actual services performed, and related costs may vary from the Company’s estimates, resulting in adjustments to clinical trial expense in future periods. Changes in these estimates that result in material changes to the Company’s accruals could materially affect its financial position and results of operations.

Stock-based Compensation Expense

The Company incurs stock-based compensation expense primarily from stock options, restricted stock units, and ESPP purchase rights.

The Company estimates the fair value of stock options granted to employees, directors and non-employees and ESPP purchase rights using the Black-Scholes option-pricing model. The Black-Scholes model requires the input of subjective assumptions, including expected volatility, expected dividend yield, expected term, risk-free rate of return and the estimated fair value of the underlying common stock on the date of grant. Prior to the Company’s initial public offering, the fair value of the common stock underlying the stock-based awards was determined on each grant date by the board of directors, with input from management, considering the most recently available third-party valuation of common shares. The grant-date fair value of restricted stock units is the fair value of the underlying stock on the award’s grant date. The Company uses the straight-line method to allocate compensation expense to reporting periods over the requisite service period, which is generally the vesting period. The Company accounts for the effect of forfeitures as they occur.

Segment Reporting

The Company manages its operations as a single operating segment for the purposes of assessing performance and making operating decisions.

Foreign Currency Transactions

The functional currency of the Company’s operation and each of its subsidiaries is U.S. dollars. All assets and liabilities denominated in a foreign currency are translated into U.S. dollars at the exchange rate prevailing on the balance sheet date. Expenses are translated at the average exchange rates prevailing during the applicable period. Foreign currency transaction gains and losses are included in the consolidated statement of operations and comprehensive loss and recorded in other expense, net, and were immaterial for the years December 31, 2021, 2020 and 2019.

Income Taxes

The Company accounts for income taxes under the asset and liability method, which requires the recognition of deferred tax assets and liabilities for the expected future tax consequences of events that have been included in the consolidated financial statements. Under this method, deferred tax assets and liabilities are determined on the basis of the differences between the consolidated financial statement carrying amounts and tax bases of assets and liabilities using enacted tax rates in effect for the period in which the temporary differences are expected to reverse. The effect of a change in tax rates on deferred tax assets and liabilities is recognized in the consolidated statements of operations and comprehensive loss in the period that includes the enactment date.

Deferred income taxes comprise the impact of temporary differences between assets and liabilities recognized for financial reporting purposes and the amounts recognized for income tax reporting purposes, net operating loss carryforwards, and other tax credits measured by applying currently enacted tax laws. A valuation allowance is provided when necessary to reduce deferred tax assets to an amount that is more likely than not to be realized. If the Company determines that it would be able to realize its deferred tax assets in the future in excess of their net recorded amount, it would make an adjustment to the deferred tax asset valuation allowance, which would reduce the provision for income taxes. The Company recognizes benefits of uncertain tax positions if it is more likely than not that such positions will be sustained upon examination based solely on their technical merits, as the largest amount of benefit that is more likely than not to be realized upon the ultimate settlement. The Company’s policy is to recognize interest and penalties related to the underpayment of income taxes as a component of income tax expense or benefit.

Comprehensive Loss

Comprehensive loss is equal to net loss for all periods presented.

Net Loss Per Share Attributable to Common Stockholders

Basic net loss per share is calculated by dividing the net loss attributable to common stockholders by the weighted-average number of shares of common stock outstanding during the period, without consideration for common stock equivalents. Diluted net loss per share is the same as basic net loss per share, since the effects of potentially dilutive securities are antidilutive given the net loss for each period presented.

The Company applies the two-class method to compute basic and diluted net loss per share when it has issued shares that meet the definition of participating securities. The two-class method determines net loss per share for each class of common stock and participating securities according to dividends declared or accumulated and participation rights in undistributed earnings. The two-class method requires net loss available to common stockholders for the period to be allocated between common and participating securities based upon their respective rights to share in the earnings as if all net loss for the period had been distributed. The Company’s convertible preferred stock participated in any dividends declared by the Company and are therefore considered to be participating securities. The participating securities were not required to participate in the losses of the Company, and therefore during periods of loss there was no allocation required under the two-class method. Upon the consummation of the Company’s initial public offering in July 2020, all shares of convertible preferred stock outstanding and accrued cumulative dividends automatically converted into common stock.

Adopted Accounting Pronouncements

In February 2016, the Financial Accounting Standards Board, or FASB, issued ASU No. 2016-02, Topic 842, Leases (ASU 2016-02). ASU 2016-02 requires an entity to recognize assets and liabilities arising from a lease for both operating and finance leases. ASU No. 2016-02 also requires new qualitative and quantitative disclosures to help investors and other financial statement users better understand the amount, timing, and uncertainty of cash flows arising from leases. In June 2020, the FASB issued ASU No. 2020-05, which extended the effective date of ASU No. 2016-02 for non-public business entities, including smaller reporting companies, to fiscal years beginning after December 15, 2021, with early adoption permitted. The Company adopted ASC 842 on January 1, 2021 using the alternative modified transition method, which applies the standard as of the adoption date and therefore, the Company has not applied the standard to the comparative periods presented in the Company's financial statements. The Company elected the following practical expedients:

(i)

not to reassess prior conclusions on whether any expired or existing contracts are or contain a lease, lease classification, and initial direct costs;

(ii)

combine lease and non-lease components

(iii)

not to recognize ROU assets or lease liabilities for short term leases

As a lessee, the primary impact of the adoption of ASC 842 was the recognition of operating and finance lease ROU assets of $0.3 million and $0.2 million, respectively, and operating and finance lease liabilities of $0.3 million and $0.2 million, respectively, as of January 1, 2021. ROU assets are presented within other assets, current lease liabilities are presented within accrued expenses and other current liabilities, and non-current lease liabilities are presented within other non-current liabilities on the consolidated balance sheet. See Note 6 "Leases" for additional details.

In December 2019, the FASB issued ASU No. 2019-12, Income Taxes, Topic 740: Simplifying the Accounting for Income Taxes, which is intended to simplify various aspects related to accounting for income taxes. The pronouncement is effective for fiscal years, and for interim periods within those fiscal years, beginning after December 15, 2021. ASU 2019-12 is effective for the Company beginning January 1, 2022. Early adoption is permitted. The Company adopted this standard as of January 1, 2021 on a prospective basis and there was no material impact on its consolidated financial statements and disclosures as a result of the adoption.

Acquisition of Assets and Ownership

12 Months Ended

Dec. 31, 2021

Business Combinations [Abstract]

ACQUISITION OF ASSETS AND OWNERSHIP

(3) ACQUISITION OF ASSETS AND OWNERSHIP

On October 4, 2021, the Company entered into a stock purchase agreement with ScalmiBio, Inc., or ScalmiBio, as the Company expands its pipeline with plans to develop new anti-cancer drug candidates based on ScalmiBio’s platform. Under the terms of the stock purchase agreement, the Company made an initial payment to the stockholders of ScalmiBio at closing on October 4, 2021 of approximately $4.5 million in cash, net of certain expenses and adjustments, and will make an additional payment of $2.0 million at the one-year anniversary of the transaction subject to ScalmiBio employee remaining employed with the Company at the anniversary date. This additional payment will be recorded as compensation expense in the Company’s statement of operations and comprehensive loss over the one-year period. In addition, the Company has agreed to pay up to $35.0 million, in aggregate, in certain milestones based on the clinical development of the acquired ScalmiBio technology and has also agreed to pay a low single digit royalty on net sales of any products developed from the ScalmiBio acquired technology for a defined term. The Company has the option to buy-out the royalty payment, prior to the first marketing approval of the developed product.

The Company’s CEO and President, who is also a director, was also a director of ScalmiBio prior to the acquisition, and owned 31.7% of ScalmiBio stock. As a result, he received or will receive a proportional share of the consideration to ScalmiBio stockholders as described above. He also received approximately $87,000 out of the closing proceeds for the repayment of a note and accrued interest for a loan to ScalmiBio. Given his interest in the ScalmiBio acquisition, the Company’s audit committee approved the acquisition under its related-party transaction policy and the Company’s CEO recused himself from the negotiation and approval of the transaction.

To determine the accounting for this transaction under ASC 805 Business Combinations, an assessment was made as to whether an integrated set of assets and activities should be accounted for as a business combination or an asset acquisition. The guidance requires an initial screen test to determine if substantially all of the fair value of the gross assets acquired is concentrated in a single asset or group of similar assets. If that screen is met, the set is not considered a business. The Company concluded that substantially all of the fair value is concentrated in a group of similar identifiable assets. Pursuant to asset acquisition accounting, acquired IPR&D with no alternative future use is expensed at acquisition. Accordingly, $4.7 million including $0.2 million of legal and other professional fees related to the acquisition, was recognized in “Research and development” expenses in the consolidated Statements of Operations and Comprehensive Loss for the year ended December 31, 2021.

Fair Value of Financial Instruments

12 Months Ended

Dec. 31, 2021

Fair Value Disclosures [Abstract]

FAIR VALUE OF FINANCIAL INSTRUMENTS

(4) FAIR VALUE OF FINANCIAL INSTRUMENTS

The fair value of the Company’s financial assets and liabilities are determined in accordance with the fair value hierarchy established in ASC 820, Fair Value Measurements and Disclosures. ASC 820 defines fair value as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. The fair value hierarchy of ASC 820 requires an entity to maximize the use of observable inputs when measuring fair value and classifies those inputs into three levels:

Level 1—Observable inputs, such as quoted prices in active markets;

Level 2—Inputs, other than the quoted prices in active markets, which are observable either directly or indirectly such as quoted prices for similar assets or liabilities; quoted prices in markets that are not active; or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the instrument’s anticipated life; and

Level 3—Unobservable inputs in which there is little or no market data, which require the reporting entity to develop its own assumptions.

Cash and cash equivalents are stated at cost which approximate their respective fair values on the Company’s consolidated balance sheets. Where quoted prices are available in an active market, securities are classified as Level 1. The Company classifies money market funds as Level 1. When quoted market prices are not available for the specific security, then the Company estimates fair value by using quoted prices for identical or similar instruments in markets that are not active and model-based valuation techniques for which all significant inputs are observable in the market or can be corroborated by observable market data for substantially the full term of the assets. Where applicable, these models project future cash flows and discount the future amounts to a present value using market-based observable inputs obtained from various third-party data providers, including but not limited to benchmark yields, reported trades and broker/dealer quotes. Where applicable the market approach utilizes prices and information from market transactions for similar or identical assets.

The following table sets forth the Company’s financial assets that are measured at fair value on a recurring basis by level within the fair value hierarchy (in thousands):

	As of December 31, 2021
	Level 1		Level 2		Level 3		Fair Value
Financial assets
Cash equivalents
Money market funds	$	357,181	$	—	$	—	$	357,181

	As of December 31, 2020
	Level 1		Level 2		Level 3		Fair Value
Financial assets
Cash equivalents
Money market funds	$	424,115	$	—	$	—	$	424,115

The Company did not have any outstanding financial liabilities to be re-measured on a recurring basis as of December 31, 2021 and 2020.

There were no transfers of assets or liabilities between the fair value measurement levels during the years ended December 31, 2021 and 2020.

The carrying values of the Company’s financial instruments, such as accounts payable and accrued expenses and other current liabilities, approximated fair value due to the short-term nature of these items.

- Definition

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

+ References + Details

Balance Sheet Components

12 Months Ended

Dec. 31, 2021

Balance Sheet Related Disclosures [Abstract]

BALANCE SHEET COMPONENTS

(5) BALANCE SHEET COMPONENTS

Property and Equipment, Net

The following table presents the components of property and equipment, net as of December 31, 2021 and 2020 (in thousands):

	December 31,			December 31,
	2021			2020
Laboratory Equipment	$	324		$	—
Computer hardware and software		241			63
Leasehold improvements		229			5
Furniture and fixtures		166			9
Property and equipment, gross		960			77
Less: accumulated depreciation and amortization		(63	)		(25	)
Property and equipment, net	$	897		$	52

Depreciation and amortization expense was nominal, $0.2 million and $0.4 million for years ended December 31, 2021, 2020 and 2019, respectively.

In July 2020, the Company transferred certain lab equipment and other assets to Tallac Therapeutics, Inc. (formerly known as Tollnine, Inc., or Tollnine), or Tallac Therapeutics, a related-party (Note 11), in exchange for $0.6 million.

Other Assets

The following table presents the components of other assets, net as of December 31, 2021 and 2020 (in thousands):

	December 31,		December 31,
.	2021		2020
Long-term prepaid clinical expenses	$	6,694	$	—
Long-term prepaid contract manufacturing costs		2,854		—
Operating lease right-of-use assets		1,829		—
Finance lease right-of-use assets		746		—
Deposits		144		10
	$	12,267	$	10

Accrued Expenses and Other Current Liabilities

The following table presents the components of accrued expenses and other current liabilities as of December 31, 2021 and 2020 (in thousands):

	December 31,		December 31,
	2021		2020
Accrued clinical and nonclinical study costs	$	4,125	$	1,401
Accrued compensation and related expenses		3,294		1,974
Accrued professional fees		790		300
Accrued contract manufacturing		693		2,123
Finance lease liabilities, current		429		—
Operating lease liabilities, current		313		—
Other		257		151
Accrued federal income tax		—		179
Total accrued expenses and other current liabilities	$	9,901	$	6,128

Leases

12 Months Ended

Dec. 31, 2021

Leases [Abstract]

LEASES

(6) LEASES

In 2017, the Company entered into a lease agreement for office space for a period of five years and four months, commencing February 1, 2018 and ending May 31, 2023. In July 2020, the Company (i) assigned to Tallac Therapeutics, Inc., or Tallac Therapeutics, a related party, the Company’s lease with respect to the premises located at 866 Malcolm Road, Burlingame, California, and (ii) entered a sub-lease agreement for the same premise from Tallac Therapeutics. The sub-lease is an operating lease. As of December 31, 2021, the Company had approximately $0.2 million right-of-use asset and lease liability related to this lease.

The Company evaluated its vendor contracts to identify embedded leases, if any, and noted that a pharmaceutical support services agreement entered into in May 2016, included leases under ASC 842 because the Company has the right to direct the use of certain equipment. The embedded leases commenced in September 2020 and expire in August 2023 with no stated option to extend the term. The Company classified the leases as finance leases.

In May 2021, the Company entered into a lease agreement for office space totaling approximately 10,000 square feet at 323 Allerton Avenue, South San Francisco, California. The term of the lease is from July 5, 2021 to August 31, 2026, with early entry date of June 6, 2021. The lease does not provide an option to extend after it expires. The total lease payments for the life of the lease is approximately $2.0 million. The Company obtained the right to direct the usage of the office space on the early entry date, and therefore considered June 6, 2021 as the lease commencement date. The lease was evaluated as an operating lease. As of December 31, 2021, the Company had a ROU asset and lease liability of approximately $1.6 million and $1.8 million, respectively, related to this lease.

The ROU assets recorded under the operating lease and finance lease were $1.8 million and $0.7 million, respectively, at December 31, 2021. The amounts were included in the other assets on the consolidated balance sheet.

The following table presents the maturities and balance sheet information of the Company's operating and finance lease liabilities as of December 31, 2021 (in thousands, except lease term and discount rate):

	December 31, 2021
	Operating Leases			Finance Leases
2022	$	519		$	432
2023		482			288
2024		433			—
2025		446			—
Thereafter		301			—
Total lease payments		2,181			720
Less: imputed interest		(166	)		(11	)
Total lease liabilities	$	2,015		$	709

Lease liabilities: current ⁽ⁱ⁾	$	457		$	429
Lease liabilities: non-current ⁽ⁱⁱ⁾		1,558			280
Total lease liabilities	$	2,015		$	709

Weighted average remaining lease term (in years)		4.3			1.7
Weighted average discount rate		3.5	%		1.7	%

(i)	Current lease liabilities are presented within accrued expenses and other current liabilities and payable and accrued liabilities due to related party of $0.7 million and $0.1 million, respectively, on the consolidated balance sheet.

(ii)	Non-current lease liabilities are presented within other non-current liabilities on the consolidated balance sheet, which includes $0.1 million due to Tallac Therapeutics.

The following table presents the components of lease costs (in thousands):


	Year Ended December 31, 2021
Operating lease cost	$	360
Variable lease cost and other, net ⁽ⁱ⁾		84
Finance lease cost
Amortization of right-of-use assets		369
Interest		13
Total lease cost	$	826

(i)

The variable lease cost and other, net is comprised primarily of common area maintenance charges for the operating lease, which is dependent on usage. These costs are classified as operating lease expense due to the election to not separate lease and non-lease components. These costs were not included within the measurement of the Company’s operating lease ROU assets and operating lease liabilities.

The following table presents supplemental cash flow information related to leases:


	Year Ended December 31, 2021
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows from operating leases	$	243
Operating cash flows from finance leases	$	11
Financing cash flows from finance leases	$	281
Right-of-use asset acquired under leases
Operating leases	$	1,780
Finance leases	$	776

ASC 840 Disclosures

The Company elected the alternative modified transition method, which applies ASC 842 as of the effective date on January 1, 2021. Prior to the adoption of ASC 842, the Company applied ASC 840 to its lease transactions.

The following table presents the future minimum lease commitments under the Company’s operating leases as of December 31, 2020, as previously disclosed (in thousands):

	December 31, 2020
2021	$	140
2022-2023		206
Total future minimum lease payments	$	346

Rent expense was $0.6 million and $0.8 million for the years ended December 31, 2020 and 2019, respectively.

Term Loan

12 Months Ended

Dec. 31, 2021

Debt Disclosure [Abstract]

TERM LOAN

(7) TERM LOAN

The Company’s wholly-owned subsidiaries Alexo Therapeutics International and Sirpant Therapeutics, as borrowers, entered into a Loan and Security Agreement, or the Loan Agreement, dated as of December 20, 2019, with Silicon Valley Bank, or SVB, and WestRiver, collectively as lenders, and SVB, as administrative agent and collateral agent. On the closing date of the Loan Agreement in December 2019, $6.0 million was funded to the Company. In December 2020, the Company fully repaid the loan balance.

In conjunction with the Loan Agreement, the Company issued warrants to purchase Series B convertible preferred stock to SVB and WestRiver, and recorded a warrant liability of approximately $0.4 million at the date of issuance. The Company also determined that certain loan features were embedded derivatives requiring bifurcation and separate accounting, and recorded a term loan compound derivative liability of approximately $51,000. The Company measured its Series B convertible preferred stock warrant liability and term loan compound derivative liability at fair value on a recurring basis, which were classified as Level 3 liabilities. During the year ended December 31, 2020, the increase in fair value in warrant liability was approximately $658,000. During the year ended December 31, 2020, the decreases in fair value in compound derivative liability was approximately $8,000. Those amounts were recognized as a component of other income (expense), net in the consolidated statement of operations and comprehensive loss. The Company reclassified the preferred stock warrant liability balance into additional paid-in capital in July 2020 with no further re-measurement required, as the common stock warrants are considered permanent equity effective with the completion of the initial public offering. The compound derivative liability was extinguished upon the extinguishment of the host instrument in December 2020.

- Definition

The entire disclosure for information about short-term and long-term debt arrangements, which includes amounts of borrowings under each line of credit, note payable, commercial paper issue, bonds indenture, debenture issue, own-share lending arrangements and any other contractual agreement to repay funds, and about the underlying arrangements, rationale for a classification as long-term, including repayment terms, interest rates, collateral provided, restrictions on use of assets and activities, whether or not in compliance with debt covenants, and other matters important to users of the financial statements, such as the effects of refinancing and noncompliance with debt covenants.

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+ Details

Stockholders' Equity

12 Months Ended

Dec. 31, 2021

Equity [Abstract]

STOCKHOLDERS? EQUITY

(8) STOCKHOLDERS’ EQUITY

On July 21, 2020, the Company’s amended and restated certificate of incorporation became effective, authorizing 1,000,000,000 shares of common stock and 100,000,000 shares of undesignated preferred stock. As of December 31, 2021 and 2020, the Company had 40,587,067 and 39,844,522 shares of common stock outstanding, respectively.

Common Stock

In July 2020, the Company consummated its initial public offering and issued 9,775,000 shares of common stock for net proceeds of approximately $169.5 million, after deducting underwriting discounts and commissions of $13.0 million and offering-related expenses of $3.2 million. Upon the closing of the initial public offering, all shares of convertible preferred stock outstanding and accrued cumulative dividends were automatically converted into 23,934,533 shares of common stock.

In December 2020, the Company consummated its follow-on public offering and issued 2,737,000 shares of common stock for net proceeds of approximately $194.9 million, after deducting underwriting discounts and commissions of $12.5 million and offering-related expenses of $0.7 million.

Common stock reserved for future issuance as of December 31, 2021 consists of the following:

	December 31,
	2021
Stock options issued and outstanding		5,128,639
Restricted stock units issued and outstanding		15,075
Remaining shares available for future issuance under equity incentive plan		3,407,898
Employee Stock Purchase Plan shares authorized for future issuance		790,822
Total		9,342,434

Dividends

Prior to the Company’s initial public offering, cumulative dividends of 6.0% per annum of the original issue price for each convertible preferred stock series were payable when and as declared by the Company’s Board of Directors, or Board of Directors, upon the occurrence of a liquidation event or upon a contingent mandatory conversion of the convertible preferred stock in connection with a qualified initial public offering as described below. The Series A original issue price was $6.58, and the Series B and Series C original issue price was $9.4972. The original issue price was subject to adjustment in the event of any share dividend, share split, combination, consolidation or other recapitalization. The dividends accrued from day to day from the issue date of such preferred stock whether or not declared and were cumulative. In addition, the preferred stockholders participated on an as-converted basis in any dividends payable to common stockholders. As of July 20, 2020, there were approximately $18.0 million of accrued cumulative dividends on the Series A, Series B and Series C convertible preferred stock, which became payable upon the consummation of the Company’s initial public offering and automatically converted into 2,564,759 shares of the Company’s common stock.

- Definition

The entire disclosure for shareholders' equity comprised of portions attributable to the parent entity and noncontrolling interest, including other comprehensive income. Includes, but is not limited to, balances of common stock, preferred stock, additional paid-in capital, other capital and retained earnings, accumulated balance for each classification of other comprehensive income and amount of comprehensive income.

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-URI http://asc.fasb.org/extlink&oid=123467817&loc=SL123496189-112644

Reference 13: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 16
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=123467817&loc=SL123496180-112644

Reference 14: http://www.xbrl.org/2003/role/disclosureRef
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-Name Accounting Standards Codification
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Reference 15: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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-Subparagraph (SX 210.4-08(e)(1))
-URI http://asc.fasb.org/extlink&oid=120395691&loc=d3e23780-122690

+ Details

Stock-Based Compensation

12 Months Ended

Dec. 31, 2021

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

STOCK-BASED COMPENSATION

(9) STOCK-BASED COMPENSATION

Equity Incentive Plans

2015 Share Award Scheme

During 2015, the Company adopted an equity compensation plan, the 2015 Share Award Scheme, or the 2015 Share Award Scheme, for eligible employees, officers, directors, advisors, and consultants. The 2015 Share Award Scheme provided for the grant of incentive and non-statutory share options. The 2015 Share Award Scheme permitted the Company to grant up to 2,143,117 shares of common stock pursuant to awards granted thereunder, including incentive share options, non-statutory share options, conditional share awards and restricted share awards.

2020 Equity Incentive Plan

On April 1, 2020, the Board of Directors approved a new equity incentive plan, or the 2020 Equity Incentive Plan, that replaced the 2015 Share Award Scheme. The 2020 Equity Incentive Plan permitted the issuance of up to 4,379,139 shares of the Company’s common stock pursuant to awards granted under it, and authorized the award of stock options, restricted stock awards, stock appreciation rights and restricted stock units to employees, directors, and consultants.

2020 Amended and Restated Equity Incentive Plan

In July 2020, the Company adopted the Amended and Restated 2020 Equity Incentive Plan, or the 2020 Plan. The 2020 Plan replaced the Company’s 2020 Equity Incentive Plan and a total of 7,874,862 shares were reserved under the 2020 Plan.

The terms of the stock option agreements, including vesting requirements, are determined by the Board of Directors, subject to the provisions of the 2020 Plan. The term of the options generally expire, upon the earliest of (i) termination of continuous service for cause (ii) three months after the termination of continuous service for reasons other than cause, death or disability (iii) twelve months after the termination of continuous service due to disability (iv) eighteen months after the employee’s death if the employee died during the period of continuous service (v) expiration date in the grant notice or (vi) the day before the tenth anniversary of the date of grant. The per share exercise price of the incentive share options must equal at least the fair market value of a share underlying such options on the date of grant.

All awards that are canceled, forfeited or expired are returned to the 2020 Plan and are available for grant in conjunction with the issuance of new awards. Share options granted are exercisable over a maximum term of 10 years from the date of grant and generally vest over an agreed service period, usually four years. Certain share options granted under the 2020 Plan provide option holders the right to elect to exercise unvested options in exchange for common stock. Such unvested common stock is subject to a repurchase right held by the Company at the original issuance price in the event the optionee’s service to the Company is terminated either voluntarily or involuntarily. The right lapses as the underlying repurchase right expires. These repurchase terms are considered to be a forfeiture provision. The cash received from employees for exercise of unvested options is treated as a refundable deposit and is classified as a liability on the consolidated balance sheets. At December 31, 2020, there were unvested early exercised options covering an aggregate of 63 shares and the liability related to these unvested options was approximately $0. At December 31, 2021, there was no such unvested early exercised options and related liability.

Stock Option Modification

In connection with the transfer of employees to Tallac Therapeutics, Dr. Hong Wan, the Company’s former Chief Scientific Officer, and eight of the Company’s employees, or Transferred Employees, terminated their employment with the Company effective as of June 30, 2020 and became employees of Tallac Therapeutics effective as of July 1, 2020. The options to purchase shares of the Company’s common stock that were previously granted to the Transferred Employees will continue to vest and be exercisable subject to the Transferred Employees remaining service providers to the Company under the original terms of the award. The Company evaluated the change in status from an employee to a consultant in accordance with ASC 718. While the Company concluded that the change in status did not affect the vesting condition or the classification of the initial awards, the significant reduction in the level of services that the grantees were expected to provide under the original awards as compared to the level of services expected under the Tallac Services Agreement will no longer meet the substantive service condition requirements and therefore the compensation cost for the unvested awards was recognized immediately with no future service requirement. In September 2020, in connection with the resignation of the Company’s former Chief Business Officer and the entry into a consulting agreement with him, the Company evaluated the change in status from an employee to a consultant in accordance with ASC 718. While the Company concluded that

the change in status did not affect the vesting condition or the classification of the initial awards, the significant reduction in the level of services that the grantee was expected to provide under the original awards as compared to the level of services expected under the consulting agreement will no longer meet the substantive service condition requirements and therefore the compensation expense for the unvested awards expected to vest during the consultancy was recognized immediately with no future service requirement. The Company recorded $1.7 million in stock-based compensation expenses related to the modifications for the year ended December 31, 2020.

Employee Stock Purchase Plan

In July 2020, the Board of Directors and stockholders approved the ALX Oncology Holdings Inc. 2020 Employee Stock Purchase Plan, or the ESPP. The ESPP allows eligible employees to have up to 15 percent of their eligible compensation withheld and used to purchase common stock, subject to a maximum of $25,000 worth of stock purchased in a calendar year or no more than 3,000 shares in an offering period, whichever is less. An offering period consists of a six-month purchase period, with a look back feature to our stock price at the commencement of the offering period. Eligible employees can purchase the Company’s common stock at the end of the offering period at 85% of the lower of the closing price of our common stock on The Nasdaq Global Select Market on the first and last day of the offering period.

The initial number of shares of common stock available for issuance under the ESPP, was 400,000. Unless the Board of Directors provides otherwise, beginning on January 1, 2021, the maximum number of shares which shall be made available for sale under the ESPP will automatically increase on the first day in January of each calendar year (i.e., the first day of our fiscal year) during the term of the ESPP by an amount equal to the least of:

•

800,000 shares;

•

one percent of the outstanding shares of our common stock on the last day of our immediately preceding fiscal year; or

•

such number of shares as our board of directors may determine no later than the last day of our immediately preceding fiscal year.

Accordingly, on January 1, 2021, the number of shares available under the ESPP was increased by 398,445 shares. As of December 31, 2021, 7,623 shares of common stock have been purchased under the ESPP, and the number of shares of common stock available for issuance under the ESPP was 790,822.

Shares Available for Grant

The following table provides a summary of share option and restricted stock unit activity under the 2020 Plan:

	Shares Available to Grant

Outstanding at December 31, 2020		2,835,445
Authorized		1,593,781
Granted		(1,447,470	)
Canceled/forfeited		426,142
Outstanding at December 31, 2021		3,407,898

Stock Option Activity

The following table provides a summary of share option activity under the Plan and related information:

	Outstanding Options
	Number of Options			Weighted Average Exercise Price		Weighted Average Remaining Contractual Life (Years)		Aggregate Intrinsic Value
								(in thousands)
Outstanding at December 31, 2020		4,857,308		$	8.94		8.86	$	375,270
Authorized
Granted		1,432,395			60.21
Exercised		(734,922	)		3.47
Canceled/forfeited		(426,142	)		10.62
Outstanding at December 31, 2021		5,128,639		$	23.91		8.28	$	49,745
Exercisable at December 31, 2021		3,143,797		$	7.88		7.66	$	48,625

The aggregate intrinsic values represent the total pre-tax intrinsic value, of options outstanding and exercisable calculated as the difference between the exercise price of the options and the fair value of the Company’s common stock as of December 31, 2021 and 2020. The total intrinsic value of options exercised during the years ended December 31, 2021, 2020 and 2019 were $48.1 million, $4.4 million and immaterial, respectively.

Stock Option Valuation Assumptions

The Company uses the Black-Scholes option pricing model to determine the estimated fair value of stock options at the date of the grant, and stock-based compensation is adjusted for actual forfeitures as they occur. The fair value of each option grant during the years ended December 31, 2021, 2020 and 2019 was estimated with the following assumptions:

	Year Ended December 31,
	2021	2020	2019
Expected term (in years)	5.3 - 6.1	5.8 - 6.1	4.4 - 6.0
Risk-free interest rate	0.8% - 1.4%	0.3% - 0.8%	1.7% - 2.1%
Expected dividend rate	-	-	-
Expected stock price volatility	79.7% - 86.9%	78.7% - 89.0%	75.2% - 80.5%

Expected Term. The expected term of the options represents the average period the share options are expected to remain outstanding. As the Company does not have sufficient historical information to develop reasonable expectations about future exercise patterns and post-vesting employment termination behavior, the expected term of options granted is derived from the average midpoint between the weighted average vesting and the contractual term, also known as the simplified method.

Risk-Free Interest Rate. The risk-free interest rate is based on the yield of U.S. Treasury notes as of the grant date with terms commensurate with the expected term of the option.

Dividend Yield. The expected dividends assumption is based on the Company’s expectation of not paying dividends in the foreseeable future.

Volatility. Since the Company does not have sufficient trading history for its common stock, the expected volatility is based on the historical volatilities of the common shares of comparable publicly traded companies. The Company selected companies with comparable characteristics, including enterprise value, risk profiles, position within the industry, and with historical share price information sufficient to meet the expected life of the Company’s share-based awards.

Fair Value. Historically, for all periods prior to our initial public offering, the fair value of the shares of common stock underlying our stock option was determined by the Company’s board of directors. Because there was no public market for the Company’s common stock, the board of directors determined fair value of the common stock at the time of grant of the options by considering a number of objective and subjective factors including important developments in the Company’s operations, valuations performed by an independent third party, sales of convertible preferred stock, actual operating results and financial performance, the conditions in the biotechnology industry and the economy in general, the stock price performance and volatility of comparable public companies, and the lack of liquidity of the Company’s common stock, among other factors the board of directors deemed relevant to such determination. Since the completion of our initial public offering, the fair value of each share of common stock underlying stock option grants is based on the closing price of our common stock on the Nasdaq Global Select Market as reported on the date of grant.

Restricted Stock Unit Activity

The following table provides a summary of restricted stock unit activity under the Plan and related information:

	Outstanding RSUs
	Number of RSUs		Weighted- Average Grant Date Fair Value		Weighted Average Remaining Contractual Life (Years)		Aggregate Intrinsic Value
							(in thousands)
Restricted stock units as of December 31, 2020		—	$	—
Granted		15,075		58.56
Vested		—		—
Canceled/forfeited		—		—
Restricted stock units as of December 31, 2021		15,075	$	58.56		1.83	$	324

Stock-based Compensation Expenses

Stock options granted are measured based on the grant-date fair value estimated using the Black-Scholes option pricing model. The grant-date fair value of restricted stock units is the fair value of the underlying stock on the award’s grant date. Compensation expense is recognized over the vesting period of the applicable awards on a straight-line basis. The weighted-average grant-date fair value per share for stock options granted during the years ended December 31, 2021, 2020 and 2019 was $42.29, $7.74 and $1.27, respectively. The grant date-fair value per share for restricted stock units during 2021 was $58.56. There were no restricted stock units granted in 2020 and 2019.

Stock-based compensation expense includes stock options and restricted stock units and has been reported in the Company’s consolidated statements of operations and comprehensive loss as follows (in thousands):

	2021		2020		2019
Research and development	$	5,211	$	2,551	$	105
General and administrative		8,703		2,885		33
Cost of services for related-party revenue		—		—		159
	$	13,914	$	5,436	$	297

As of December 31, 2021, there was unrecognized share-based compensation expense of $68.7 million, related to unvested share options which the Company expects to recognize over a weighted-average period of 2.8 years. There was unrecognized share-based compensation expense of $0.8 million, related to unvested restricted stock units which the Company expects to recognize over a weighted-average period of 3.6 years.

Income Taxes

12 Months Ended

Dec. 31, 2021

Income Tax Disclosure [Abstract]

INCOME TAXES

(10) INCOME TAXES

The U.S. domestic and international components of pre-tax loss for the years ending December 31, 2021, 2020 and 2019 are as follows (in thousands):

	Year Ended December 31,
	2021			2020			2019
United States	$	(30,565	)	$	(9,457	)	$	813
International		(52,919	)		(36,042	)		(20,022	)
Loss before income taxes	$	(83,484	)	$	(45,499	)	$	(19,209	)

The federal and state provision (benefit) for income taxes consist of the following (in thousands):

	Year Ended December 31,
	2021			2020		2019
Current provision for income taxes:
Federal	$	(21	)	$	239	$	33
State		—			2		1
International		—			—		—
Total current		(21	)		241		34
Deferred tax provision:
Federal		—			—		—
State		—			—		—
International		—			—		—
Total deferred		—			—		—
Provision for income taxes	$	(21	)	$	241	$	34

Deferred income taxes reflect the net tax effects of (a) temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes, and (b) operating losses and tax credit carryforwards.

A reconciliation of the U.S. federal statutory income tax rate to the effective tax for the years ended December 31, 2021, 2020 and 2019 are as follows (in thousands):

	Year Ended December 31,
	2021			2020			2019
At federal statutory income tax rate	$	(17,532	)	$	(9,555	)	$	(4,034	)
State income taxes		(105	)		(3,098	)		(1,875	)
Stock-based compensation		(4,031	)		(5	)		60
Research & Development credits		(2,131	)		(512	)		(861	)
Change in valuation allowance		11,476			5,710			3,733
Other		172			321			75
Foreign rate differential		11,032			7,380			3,886
Prior period true ups		1,098			—			(950	)
Provision for income taxes	$	(21	)	$	241		$	34

Significant components of the Company’s deferred tax assets as of December 31, 2021 and 2020 are as follows (in thousands):

	December 31,
	2021			2020
Deferred tax assets:
Loss carryforwards	$	15,407		$	7,283
Research & other credits		5,325			2,861
Other		16			76
Accrued expenses		529			383
Stock options		1,530			696
Lease Liabilities		542			—
Total deferred tax assets		23,349			11,299
Deferred tax liabilities:
Fixed assets		73			11
Lease ROU assets		541			—
Total deferred tax liabilities		614			11
Valuation allowance		(22,735	)		(11,288	)
Net deferred tax assets	$	—		$	—

ASC 740 requires that the tax benefit of net operating losses, temporary differences and credit carryforwards be recorded as an asset to the extent that management assesses that realization is "more likely than not." Realization of the future tax benefits is dependent on the Company's ability to generate sufficient taxable income within the carryforward period. Because of the Company's recent history of operating losses, management believes that recognition of the deferred tax assets arising from the above-mentioned future tax benefits is currently not likely to be realized and, accordingly, has provided a valuation allowance. The valuation allowance increased by approximately $11.4 million and $4.6 million for the years ended December 31, 2021 and 2020, respectively.

Net operating losses and tax credit carryforwards as of December 31, 2021 are as follows (in thousands):

	Amount		Expiration Years
Net operating losses, federal (Post December 31, 2017)	$	47,142	Do Not Expire
Net operating losses, state	$	68,993	2038-2040
Tax credits, federal	$	3,885	2039-2041
Tax credits, state	$	3,236	N/A
Net operating losses, foreign	$	5,509	N/A

Utilization of the Company’s U.S. net operating loss and credit carryforwards may be subject to substantial annual limitation due to the ownership change limitations provided by the Internal Revenue Code and similar state provisions. Such annual limitation could result in the expiration of the U.S. net operating loss and credit carryforwards before utilization. To date, the Company has not performed an analysis to determine whether there would be a substantial annual limitation due to a change in ownership.

Unrecognized Tax Benefits

The Company recognizes the tax benefit from uncertain tax positions if it is more likely than not that the tax positions will be sustained on examination by the tax authorities, based on the technical merits of the position. The tax benefit is measured based on the largest benefit that has a greater than 50% likelihood of being realized upon ultimate settlement. The Company recognizes interest and penalties related to unrecognized tax benefits in income tax expense. The Company will file income tax returns in the U.S. federal and California jurisdiction, which is not currently under exam, and all years since inception are opened to examination.

The unrecognized tax benefits as of December 31, 2021, 2020 and 2019 were $1.2 million, $0.8 million and $0.7 million, respectively. Future changes in the unrecognized tax benefits will not impact the effective tax rate due to the Company's full valuation allowance.

The Company has the following activity relating to unrecognized tax benefits (in thousands):

	Year Ended December 31,
	2021			2020			2019
Balance at beginning of year	$	842		$	692		$	418
Additions/reversals based on tax positions of prior years		(69	)		(64	)		2
Additions based on tax positions related to the current year		494			240			272
Lapses in statutes of limitations		(50	)		(26	)	—
Balance at end of year	$	1,217		$	842		$	692

Although it is reasonably possible that certain unrecognized tax benefits may increase or decrease within the next 12 months due to tax examination changes, settlement activities, expirations of statute of limitations or the impact on recognition and measurement considerations related to the results of published tax cases or other similar activities, the Company does not anticipate any significant changes to unrecognized tax benefits over the next 12 months. During the years ended December 31, 2021, 2020 and 2019, no interest or penalties were required to be recognized relating to unrecognized tax benefits.

- Definition

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

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 21
-URI http://asc.fasb.org/extlink&oid=121826272&loc=d3e32857-109319

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SAB Topic 11.C)
-URI http://asc.fasb.org/extlink&oid=122134291&loc=d3e330215-122817

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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-Section 50
-Paragraph 17
-Subparagraph (b)
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Reference 4: http://www.xbrl.org/2003/role/disclosureRef
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-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB TOPIC 6.I.5.Q1)
-URI http://asc.fasb.org/extlink&oid=122134291&loc=d3e330036-122817

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 14
-URI http://asc.fasb.org/extlink&oid=121826272&loc=d3e32705-109319

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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Reference 7: http://www.xbrl.org/2003/role/disclosureRef
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-Name Accounting Standards Codification
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Reference 8: http://www.xbrl.org/2003/role/disclosureRef
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-Name Accounting Standards Codification
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-SubTopic 30
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Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(h)(2))
-URI http://asc.fasb.org/extlink&oid=120395691&loc=d3e23780-122690

+ Details

Related-Party Transactions

12 Months Ended

Dec. 31, 2021

RELATED-PARTY TRANSACTIONS

(11) RELATED-PARTY TRANSACTIONS

Related-party revenue

In June 2018, the Company entered into a Research and Development Services Agreement, or Tollnine Agreement, with Tollnine Therapeutics, Inc., or Tollnine, a related-party of the Company, to provide research and development services to Tollnine. The Company’s Chief Executive Officer was the Chief Executive Officer of Tollnine until April 2020 but remains on the Board of Directors. In addition, two of the Company’s investors were also investors in Tollnine. As such, Tollnine was deemed to be a related-party. The Tollnine Agreement had an initial term of 3 years. The services were provided at a price based on the costs incurred by the Company plus a mark-up equal to 10% of such costs. The Company recognized revenue when Tollnine, as the Company’s customer, obtained control of promised goods or services, in an amount that reflects the consideration which the Company received in exchange for those goods or services.

The Company recognized related-party revenues of zero, $1.2 million and $4.8 million for the years ended December 31, 2021, 2020 and 2019, respectively, under the Tollnine Agreement. Effective as of July 1, 2020, the Company terminated the Tollnine Agreement and entered into the Tallac Services Agreement with Tallac Therapeutics.

Tallac Service Agreement

The Company entered into a research and development services agreement, or the Tallac Services Agreement, with Tallac Therapeutics effective as of July 1, 2020. The Tallac Services Agreement provides that Tallac Therapeutics will provide certain preclinical research services to the Company for a service fee based on the costs incurred by Tallac Therapeutics plus a mark-up equal to 10.0% of such costs. The Tallac Services Agreement has an initial term of four years and is renewed automatically for additional one year terms thereafter. The Company records the payments for the research and development services as research and development costs within the consolidated statement of operations and comprehensive loss. The Company has recorded $0.8 million and $0.6 million as research and development costs for the year ended December 31, 2021 and December 31, 2020.

Tallac Collaboration Agreement

On March 4, 2021, the Company entered into a Collaboration Agreement with Tallac Therapeutics to jointly develop, manufacture, and commercialize a novel class of cancer immunotherapeutics. The collaboration builds on the Company’s expertise in developing therapies that block the CD47 checkpoint pathway and expands its immuno-oncology pipeline. The companies will leverage their respective scientific and technical expertise to advance an anti-SIRPα antibody conjugated to a Toll-like receptor 9, or TLR9, agonist for targeted activation of both the innate and adaptive immune systems. The key economic components of the collaboration transaction include that both parties will share equally (a) in the cost and expenses of research and development and (b) any profit or loss.

The Company accounts for research and development, or R&D, costs in accordance ASC 730, Research and Development, which states R&D costs must be charged to expense as incurred. Accordingly, the Company records its internal and third-party costs associated with the collaboration as R&D expenses as incurred. When the Company is entitled to reimbursement of the R&D expenses that it incurs under the collaboration, the Company records those reimbursable amounts as a reduction to R&D expenses. The Company also records as R&D expenses, the portion of Tallac’s expenses that the Company is obligated to reimburse, in the period when Tallac incurs such expenses. During the year ended December 31, 2021, the Company recorded $2.8 million in R&D expenses related to the collaboration.

The Collaboration Agreement includes the right to set off clause, as such, the Company records the amount due to or reimbursable from Tallac on a net basis. As of December 31, 2021, the Company had $1.4 million of accrued expenses due to Tallac which was presented within the payable and accrued liabilities due to related party on the consolidated balance sheet.

Acquisition of assets and ownership of ScalmiBio

On October 4, 2021, the Company entered into a stock purchase agreement with ScalmiBio. The Company’s CEO and President, who is a director, was also a director of ScalmiBio prior to the acquisition, and owned 31.7% of ScalmiBio stock. Refer to Note 3 Acquisition of assets and ownership for additional discussion.

Transfer of assets to Tallac Therapeutics

In July 2020, the Company transferred certain lab equipment and other assets to Tallac Therapeutics in exchange for $0.6 million.

Operating sub-lease agreement with Tallac Therapeutics

The Company leases office space in Burlingame, California under a single operating sub-lease agreement with Tallac Therapeutics. Refer to Note 6 Leases for additional discussion.

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

(12) NET LOSS PER SHARE ATTRIBUTABLE TO COMMON STOCKHOLDERS

The following table sets forth the computation of the basic and diluted net loss per share attributable to common stockholders (in thousands, except share and per share data):

	Year Ended December 31,
	2021			2020			2019
Numerator:
Net loss	$	(83,463	)	$	(45,740	)	$	(19,243	)
Less: cumulative preferred dividends allocated to preferred stockholders		—			(5,202	)		(4,028	)
Net loss attributable to common stockholders	$	(83,463	)	$	(50,942	)	$	(23,271	)
Denominator:
Weighted-average shares of common stock outstanding		40,308,050			18,485,343			3,076,461
Net loss per share attributable to common stockholders, basic and diluted	$	(2.07	)	$	(2.76	)	$	(7.56	)

Since the Company was in a loss position for all periods presented, basic net loss per share is the same as diluted net loss per share for all periods presented as the inclusion of all potential common stock outstanding would have been anti-dilutive.

The following outstanding potentially dilutive securities were excluded from the computation of diluted net loss per share for the years ended December 31, 2021, 2020 and 2019, because including them would have been anti-dilutive:

	December 31,
	2021		2020		2019
Convertible preferred stock		—		—		10,313,808
Warrants to purchase convertible preferred stock		—		—		61,292
Common stock subject to repurchase		—		63		34,024
Options issued and outstanding		5,128,639		4,857,308		1,183,745
Restricted stock units issued and outstanding		15,075		—		—
		5,143,714		4,857,371		11,592,869

Commitments and Contingencies

12 Months Ended

Dec. 31, 2021

Commitments And Contingencies Disclosure [Abstract]

COMMITMENTS AND CONTINGENCIES

(13) COMMITMENTS AND CONTINGENCIES

Guarantees and Indemnifications

In the normal course of business, the Company enters into contracts and agreements that contain a variety of representations and warranties and provide for general indemnifications. The Company’s exposure under these agreements is unknown because it involves claims that may be made against the Company in the future but have not yet been made. To date, the Company has not paid any claims or been required to defend any action related to its indemnification obligations. However, the Company may record charges in the future as a result of these indemnification obligations. The Company also has indemnification obligations to its officers and directors for specified events or occurrences, subject to some limits, while they are serving at the Company’s request in such capacities. There have been no claims to date and the Company has director and officer insurance that may enable the Company to recover a portion of any amounts paid for future potential claims. The Company believes the fair value of these indemnification agreements is minimal. Accordingly, the Company has not recorded any liabilities for these agreements as of December 31, 2021.

Contingencies

From time to time, the Company may be a party to various claims in the normal course of business. Legal fees and other costs associated with such actions will be expensed as incurred. The Company will assess, in conjunction with its legal counsel, the need to record a liability for litigation and contingencies. Reserve estimates will be recorded when and if it is determined that a loss related matter is both probable and reasonably estimable. For the years ended December 31, 2021, 2020 and 2019, the Company had no pending or threatened litigation.

License Agreements

In March 2015, the Company entered into a license agreement, or the Stanford Agreement, with the Board of Trustees of the Leland Stanford Junior University, or Stanford, under which the Company obtained a worldwide, royalty-bearing, sublicensable license under certain patents relating to the Company’s current product candidates, to develop, manufacture and commercialize products for use in certain licensed fields, the scope of which would include the application of the licensed intellectual property in oncology. The Company paid Stanford a nonrefundable license royalty and reimbursed Stanford for past patent expenses, together totaling less than $0.1 million, and granted Stanford a specified number of shares of common stock of the Company. The Company is required to make milestone payments up to an aggregate of $5.0 million in respect of a specified number of licensed products that successfully satisfy certain clinical and regulatory milestones. The Company recorded the first milestone payment of $0.2 million during the year ended December 31, 2021.

In June 2016, the Company entered into a license agreement with Selexis SA, or Selexis, under which the Company obtained a worldwide, royalty-bearing, sublicensable license under certain patents, know-how and other intellectual property, to use Selexis generated cell lines to manufacture evorpacept, and to make, use and sell licensed product containing such compound in all fields of use. The Company paid Selexis a nominal one-time fee and will pay Selexis an annual maintenance fee. The Company also agreed to pay Selexis milestone payments up to an aggregate of 1.2 million Swiss Francs in respect of all licensed products developed and/or commercialized under the grant that successfully satisfies certain milestone events. The Company recorded a milestone payment of $0.1 million during the year ended December 31, 2021.

In March 2017, the Company entered into an agreement with Crystal Bioscience Inc. (now a subsidiary of Ligand Pharmaceuticals Incorporated), or Crystal, under which the Company obtained an assignment of certain patents, covering certain SIRPα antibodies. Under this agreement, the Company also received a worldwide, royalty-bearing non-exclusive license, with the right to grant sublicenses through multiple tiers of sublicenses, under certain of Crystal’s background patents and know-how necessary to commercialize the rights under the assigned patents. The Company agreed to pay Crystal milestone payments up to $11.1 million in respect of all licensed products developed under the assigned patents, that successfully satisfy certain clinical and regulatory milestones, each milestone being paid only once for all products. No milestone payments have been recorded as of December 31, 2021.

Other Contractual Obligations and Other Commitments

We have contractual obligations from our operating lease, manufacturing and service contracts and other research and development activities. The following table aggregates our material expected contractual obligations and commitments as of December 31, 2021 (in thousands):

	December 31, 2021
	Total		2022		2023 - 2024		2025 - 2026
Operating lease obligations⁽¹⁾	$	2,181	$	519	$	915	$	747
Finance lease obligations⁽²⁾		720		432		288		—
Manufacturing and service contracts⁽³⁾		21,211		17,578		3,550		83
Total	$	24,112	$	18,529	$	4,753	$	830

(1)

The payments consist of (i) payments due for the office space in Burlingame, California under a single operating sub-lease agreement that expires in 2023, and (ii) payments due for the office space in South San Francisco, California under a single operating lease agreement that expires in 2026. See Note 6 to our consolidated financial statements appearing elsewhere in this Annual Report on Form 10-K for details of related commitments.

(2)

Payments due for embedded finance leases related to a pharmaceutical support service contract. See Note 6 to our consolidated financial statements appearing elsewhere in this Annual Report on Form 10-K for details of related commitments.

(3)

In November 2015, we entered into a Master Service Agreement, or the MSA, with KBI Biopharma, Inc. relating to formulation development, process development and cGMP manufacturing of evorpacept for use in clinical trials on a project basis. The MSA had an initial term of three years with successive one-year renewal periods, is cancellable upon notice and is non-exclusive. Statements of work under the MSA commit us to certain future purchase obligations of approximately $20.7 million. In addition, we have commitments with two other drug product manufacturers that commit us to certain future purchase obligations of approximately $0.5 million. These amounts are based on non-cancellable commitments and forecasts that include estimates of future market demand, quantity discounts and manufacturing efficiencies that may impact timing of purchases.

The Company enters into contracts in the normal course of business with various third parties for clinical trials, preclinical research studies and testing, manufacturing and other services and products for operating purposes. These contracts generally provide for termination upon notice. Payments due upon cancellation consist only of payments for services provided or expenses incurred, including non-cancellable obligations of our service providers, up to the date of cancellation.

Subsequent Events

12 Months Ended

Dec. 31, 2021

Subsequent Events [Abstract]

SUBSEQUENT EVENTS

(14) SUBSEQUENT EVENTS

On February 7, 2022, the Company entered into a new lease, totaling approximately 11,074 square feet of office and laboratory space located in Palo Alto, California. The lease consists of two premises with a term of 96 months from their respective commencement dates. The new lease related to one of the premises has commenced in February 2022, and the other premise is expected to commence by October 2022.

The new lease provides for an annual base rent of approximately $0.8 million, which increases on an annual basis by 3%. The total lease payments to be made during the lease term are approximately $7.0 million. The Company will be entitled to a tenant improvement allowance of approximately $1.5 million for costs related to the design and construction of the premises.

Significant Accounting Policies (Policies)

12 Months Ended

Dec. 31, 2021

Basis of Presentation

Basis of Preparation

Reclassifications

Principles of Consolidation

All intercompany balances and transactions have been eliminated in consolidation.

Reverse Stock Split

Use of Estimates

Cash and Cash Equivalents

Concentration Of Credit Risk, Credit Losses And Other Risks And Uncertainties

Concentration of Credit Risk, Credit Losses and Other Risks and Uncertainties

Property and Equipment

Deferred Offering Costs

Leases

Impairment of Long-Lived Assets

Fair Value of Financial Instruments

Convertible Preferred Stock

Revenue Recognition

To date, the Company has derived revenue from providing research and development services on a time and materials basis to a related-party.

The Company recognizes such revenues over time as services are delivered, and invoices the customer as the work is incurred in arrears.

Cost of Services for Related-Party Revenue

Research and Development Costs

Asset Acquisition Including Acquired In-Process Research and Development Expenses

Asset Acquisition including Acquired In-Process Research and Development Expenses

Upfront and milestone payments made related to an asset acquisition are accrued for and expensed when the achievement of the milestone is considered probable.

Clinical and Manufacturing Accruals

Stock-based Compensation Expense

The Company incurs stock-based compensation expense primarily from stock options, restricted stock units, and ESPP purchase rights.

Segment Reporting

The Company manages its operations as a single operating segment for the purposes of assessing performance and making operating decisions.

Foreign Currency Transactions

Income Taxes

Comprehensive Loss

Comprehensive loss is equal to net loss for all periods presented.

Net Loss Per Share Attributable to Common Stockholders

Adopted Accounting Pronouncements

(i)

not to reassess prior conclusions on whether any expired or existing contracts are or contain a lease, lease classification, and initial direct costs;

(ii)

combine lease and non-lease components

(iii)

not to recognize ROU assets or lease liabilities for short term leases

Series B Preferred Stock

Convertible Preferred Stock Warrant Liability

Series B Convertible Preferred Stock Warrant Liability

Fair Value of Financial Instruments (Tables)

12 Months Ended

Dec. 31, 2021

Fair Value Disclosures [Abstract]

Financial Assets and Liabilities Measured at Fair Value on Recurring Basis

The following table sets forth the Company’s financial assets that are measured at fair value on a recurring basis by level within the fair value hierarchy (in thousands):

	As of December 31, 2021
	Level 1		Level 2		Level 3		Fair Value
Financial assets
Cash equivalents
Money market funds	$	357,181	$	—	$	—	$	357,181

	As of December 31, 2020
	Level 1		Level 2		Level 3		Fair Value
Financial assets
Cash equivalents
Money market funds	$	424,115	$	—	$	—	$	424,115

Balance Sheet Components (Tables)

12 Months Ended

Dec. 31, 2021

Balance Sheet Related Disclosures [Abstract]

Schedule of Components of Property and Equipment

The following table presents the components of property and equipment, net as of December 31, 2021 and 2020 (in thousands):

	December 31,			December 31,
	2021			2020
Laboratory Equipment	$	324		$	—
Computer hardware and software		241			63
Leasehold improvements		229			5
Furniture and fixtures		166			9
Property and equipment, gross		960			77
Less: accumulated depreciation and amortization		(63	)		(25	)
Property and equipment, net	$	897		$	52

Schedule of Components of Other Assets, Net

The following table presents the components of other assets, net as of December 31, 2021 and 2020 (in thousands):

	December 31,		December 31,
.	2021		2020
Long-term prepaid clinical expenses	$	6,694	$	—
Long-term prepaid contract manufacturing costs		2,854		—
Operating lease right-of-use assets		1,829		—
Finance lease right-of-use assets		746		—
Deposits		144		10
	$	12,267	$	10

Components of Accrued Expenses and Other Current Liabilities

The following table presents the components of accrued expenses and other current liabilities as of December 31, 2021 and 2020 (in thousands):

	December 31,		December 31,
	2021		2020
Accrued clinical and nonclinical study costs	$	4,125	$	1,401
Accrued compensation and related expenses		3,294		1,974
Accrued professional fees		790		300
Accrued contract manufacturing		693		2,123
Finance lease liabilities, current		429		—
Operating lease liabilities, current		313		—
Other		257		151
Accrued federal income tax		—		179
Total accrued expenses and other current liabilities	$	9,901	$	6,128

Leases (Tables)

12 Months Ended

Dec. 31, 2021

Leases [Abstract]

Schedule of Maturities of Operating and Finance Lease Liabilities

	December 31, 2021
	Operating Leases			Finance Leases
2022	$	519		$	432
2023		482			288
2024		433			—
2025		446			—
Thereafter		301			—
Total lease payments		2,181			720
Less: imputed interest		(166	)		(11	)
Total lease liabilities	$	2,015		$	709

Lease liabilities: current ⁽ⁱ⁾	$	457		$	429
Lease liabilities: non-current ⁽ⁱⁱ⁾		1,558			280
Total lease liabilities	$	2,015		$	709

Weighted average remaining lease term (in years)		4.3			1.7
Weighted average discount rate		3.5	%		1.7	%

(i)	Current lease liabilities are presented within accrued expenses and other current liabilities and payable and accrued liabilities due to related party of $0.7 million and $0.1 million, respectively, on the consolidated balance sheet.

(ii)	Non-current lease liabilities are presented within other non-current liabilities on the consolidated balance sheet, which includes $0.1 million due to Tallac Therapeutics.

Components of Lease Costs

The following table presents the components of lease costs (in thousands):


	Year Ended December 31, 2021
Operating lease cost	$	360
Variable lease cost and other, net ⁽ⁱ⁾		84
Finance lease cost
Amortization of right-of-use assets		369
Interest		13
Total lease cost	$	826

(i)

Supplemental Cash Flow Information Related to Leases

The following table presents supplemental cash flow information related to leases:


	Year Ended December 31, 2021
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows from operating leases	$	243
Operating cash flows from finance leases	$	11
Financing cash flows from finance leases	$	281
Right-of-use asset acquired under leases
Operating leases	$	1,780
Finance leases	$	776

Schedule of Future Minimum Lease Commitments under Operating Leases

The following table presents the future minimum lease commitments under the Company’s operating leases as of December 31, 2020, as previously disclosed (in thousands):

	December 31, 2020
2021	$	140
2022-2023		206
Total future minimum lease payments	$	346

Stockholders' Equity (Tables)

12 Months Ended

Dec. 31, 2021

Equity [Abstract]

Common Stock Reserved for Future Issuance

Common stock reserved for future issuance as of December 31, 2021 consists of the following:

	December 31,
	2021
Stock options issued and outstanding		5,128,639
Restricted stock units issued and outstanding		15,075
Remaining shares available for future issuance under equity incentive plan		3,407,898
Employee Stock Purchase Plan shares authorized for future issuance		790,822
Total		9,342,434

Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2021

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Summary of Shares Available for Grant

The following table provides a summary of share option and restricted stock unit activity under the 2020 Plan:

	Shares Available to Grant

Outstanding at December 31, 2020		2,835,445
Authorized		1,593,781
Granted		(1,447,470	)
Canceled/forfeited		426,142
Outstanding at December 31, 2021		3,407,898

Summary of Share Option Activity

The following table provides a summary of share option activity under the Plan and related information:

	Outstanding Options
	Number of Options			Weighted Average Exercise Price		Weighted Average Remaining Contractual Life (Years)		Aggregate Intrinsic Value
								(in thousands)
Outstanding at December 31, 2020		4,857,308		$	8.94		8.86	$	375,270
Authorized
Granted		1,432,395			60.21
Exercised		(734,922	)		3.47
Canceled/forfeited		(426,142	)		10.62
Outstanding at December 31, 2021		5,128,639		$	23.91		8.28	$	49,745
Exercisable at December 31, 2021		3,143,797		$	7.88		7.66	$	48,625

Schedule of Fair Value of Each Option Grant Using Black-Scholes Option-Pricing Model

The fair value of each option grant during the years ended December 31, 2021, 2020 and 2019 was estimated with the following assumptions:

	Year Ended December 31,
	2021	2020	2019
Expected term (in years)	5.3 - 6.1	5.8 - 6.1	4.4 - 6.0
Risk-free interest rate	0.8% - 1.4%	0.3% - 0.8%	1.7% - 2.1%
Expected dividend rate	-	-	-
Expected stock price volatility	79.7% - 86.9%	78.7% - 89.0%	75.2% - 80.5%

Summary of Restricted Stock Unit Activity

The following table provides a summary of restricted stock unit activity under the Plan and related information:

	Outstanding RSUs
	Number of RSUs		Weighted- Average Grant Date Fair Value		Weighted Average Remaining Contractual Life (Years)		Aggregate Intrinsic Value
							(in thousands)
Restricted stock units as of December 31, 2020		—	$	—
Granted		15,075		58.56
Vested		—		—
Canceled/forfeited		—		—
Restricted stock units as of December 31, 2021		15,075	$	58.56		1.83	$	324

Summary of Share-Based Compensation Expense

	2021		2020		2019
Research and development	$	5,211	$	2,551	$	105
General and administrative		8,703		2,885		33
Cost of services for related-party revenue		—		—		159
	$	13,914	$	5,436	$	297

Income Taxes (Tables)

12 Months Ended

Dec. 31, 2021

Income Tax Disclosure [Abstract]

Schedule Components of Loss Before Income Taxes

The U.S. domestic and international components of pre-tax loss for the years ending December 31, 2021, 2020 and 2019 are as follows (in thousands):

	Year Ended December 31,
	2021			2020			2019
United States	$	(30,565	)	$	(9,457	)	$	813
International		(52,919	)		(36,042	)		(20,022	)
Loss before income taxes	$	(83,484	)	$	(45,499	)	$	(19,209	)

Schedule of Income Tax Provision (Benefit)

The federal and state provision (benefit) for income taxes consist of the following (in thousands):

	Year Ended December 31,
	2021			2020		2019
Current provision for income taxes:
Federal	$	(21	)	$	239	$	33
State		—			2		1
International		—			—		—
Total current		(21	)		241		34
Deferred tax provision:
Federal		—			—		—
State		—			—		—
International		—			—		—
Total deferred		—			—		—
Provision for income taxes	$	(21	)	$	241	$	34

Schedule of Statutory and Effective Income Tax Rate Reconciliation

A reconciliation of the U.S. federal statutory income tax rate to the effective tax for the years ended December 31, 2021, 2020 and 2019 are as follows (in thousands):

	Year Ended December 31,
	2021			2020			2019
At federal statutory income tax rate	$	(17,532	)	$	(9,555	)	$	(4,034	)
State income taxes		(105	)		(3,098	)		(1,875	)
Stock-based compensation		(4,031	)		(5	)		60
Research & Development credits		(2,131	)		(512	)		(861	)
Change in valuation allowance		11,476			5,710			3,733
Other		172			321			75
Foreign rate differential		11,032			7,380			3,886
Prior period true ups		1,098			—			(950	)
Provision for income taxes	$	(21	)	$	241		$	34

Schedule of Components of Deferred Tax Assets

Significant components of the Company’s deferred tax assets as of December 31, 2021 and 2020 are as follows (in thousands):

	December 31,
	2021			2020
Deferred tax assets:
Loss carryforwards	$	15,407		$	7,283
Research & other credits		5,325			2,861
Other		16			76
Accrued expenses		529			383
Stock options		1,530			696
Lease Liabilities		542			—
Total deferred tax assets		23,349			11,299
Deferred tax liabilities:
Fixed assets		73			11
Lease ROU assets		541			—
Total deferred tax liabilities		614			11
Valuation allowance		(22,735	)		(11,288	)
Net deferred tax assets	$	—		$	—

Summary of Net Operating Loss and Tax Credit Carryforwards

Net operating losses and tax credit carryforwards as of December 31, 2021 are as follows (in thousands):

	Amount		Expiration Years
Net operating losses, federal (Post December 31, 2017)	$	47,142	Do Not Expire
Net operating losses, state	$	68,993	2038-2040
Tax credits, federal	$	3,885	2039-2041
Tax credits, state	$	3,236	N/A
Net operating losses, foreign	$	5,509	N/A

Schedule of Unrecognized Tax Benefits

The Company has the following activity relating to unrecognized tax benefits (in thousands):

	Year Ended December 31,
	2021			2020			2019
Balance at beginning of year	$	842		$	692		$	418
Additions/reversals based on tax positions of prior years		(69	)		(64	)		2
Additions based on tax positions related to the current year		494			240			272
Lapses in statutes of limitations		(50	)		(26	)	—
Balance at end of year	$	1,217		$	842		$	692

Net Loss Per Share Attributable to Common Stockholders (Tables)

12 Months Ended

Dec. 31, 2021

Earnings Per Share [Abstract]

Computation of Basic and Diluted Net Loss per Share

The following table sets forth the computation of the basic and diluted net loss per share attributable to common stockholders (in thousands, except share and per share data):

	Year Ended December 31,
	2021			2020			2019
Numerator:
Net loss	$	(83,463	)	$	(45,740	)	$	(19,243	)
Less: cumulative preferred dividends allocated to preferred stockholders		—			(5,202	)		(4,028	)
Net loss attributable to common stockholders	$	(83,463	)	$	(50,942	)	$	(23,271	)
Denominator:
Weighted-average shares of common stock outstanding		40,308,050			18,485,343			3,076,461
Net loss per share attributable to common stockholders, basic and diluted	$	(2.07	)	$	(2.76	)	$	(7.56	)

Summary of Outstanding Potentially Dilutive Securities Were Excluded from Computation of Diluted Net Loss Per Share

	December 31,
	2021		2020		2019
Convertible preferred stock		—		—		10,313,808
Warrants to purchase convertible preferred stock		—		—		61,292
Common stock subject to repurchase		—		63		34,024
Options issued and outstanding		5,128,639		4,857,308		1,183,745
Restricted stock units issued and outstanding		15,075		—		—
		5,143,714		4,857,371		11,592,869

Commitments and Contingencies (Tables)

12 Months Ended

Dec. 31, 2021

Commitments And Contingencies Disclosure [Abstract]

Summary of Company's Commitments and Contractual Obligations

The following table aggregates our material expected contractual obligations and commitments as of December 31, 2021 (in thousands):

	December 31, 2021
	Total		2022		2023 - 2024		2025 - 2026
Operating lease obligations⁽¹⁾	$	2,181	$	519	$	915	$	747
Finance lease obligations⁽²⁾		720		432		288		—
Manufacturing and service contracts⁽³⁾		21,211		17,578		3,550		83
Total	$	24,112	$	18,529	$	4,753	$	830

(1)

(2)

(3)

Significant Accounting Policies - Additional Information (Details)		12 Months Ended
	Jul. 08, 2020	Dec. 31, 2021 USD ($) Segment	Jan. 01, 2021 USD ($)	Dec. 31, 2020 USD ($)	Jul. 31, 2020 shares	Jul. 21, 2020 shares
Significant Accounting Policies [Line Items]
Accrued expenses and other current liabilities		$ 9,901,000		$ 6,128,000
Payable and accrued liabilities due to related party		$ 1,630,000		72,000
Reverse stock split, description		On July 8, 2020, the Company’s board of directors approved an amendment to the Company’s certificate of incorporation to effect a 1-for-6.5806 reverse split of its common stock and convertible preferred stock.
Reverse stock split, conversion ratio	0.151961827
Impairment charges		$ 0
Number of operating segment \| Segment		1
Operating lease ROU assets		$ 1,800,000
Finance lease ROU assets		700,000
Operating lease liabilities		2,015,000
Finance lease liabilities		$ 709,000
Finance lease, right-of-use asset, statement of financial position [extensible list]		us-gaap:OtherAssets
Finance lease, liability, current, statement of financial position [extensible list]		us-gaap:OtherLiabilitiesCurrent
Finance lease, liability, noncurrent, statement of financial position [extensible list]		Other non-current liabilities
Operating lease, right-of-use asset, statement of financial position [extensible list]		us-gaap:PrepaidExpenseAndOtherAssets
Operating lease, liability, current, statement of financial position [extensible list]		us-gaap:OtherLiabilitiesCurrent
Operating lease, liability, noncurrent, statement of financial position [extensible list]		Other non-current liabilities
ASU 2016-02
Significant Accounting Policies [Line Items]
Change in Accounting Principle, Accounting Standards Update, Adopted [true false]		true
Change in Accounting Principle, Accounting Standards Update, Adoption Date		Jan. 01, 2021
Operating lease ROU assets			$ 300,000
Finance lease ROU assets			200,000
Operating lease liabilities			300,000
Finance lease liabilities			$ 200,000
ASU 2019-12
Significant Accounting Policies [Line Items]
Change in Accounting Principle, Accounting Standards Update, Adopted [true false]		true
Change in Accounting Principle, Accounting Standards Update, Adoption Date		Jan. 01, 2021
Change in Accounting Principle, Accounting Standards Update, Immaterial Effect [true false]		true
Initial Public Offering \| Common Stock
Significant Accounting Policies [Line Items]
Convertible shares converted in to common stock \| shares					23,934,533	23,934,533
Revision of Prior Period, Reclassification, Adjustment
Significant Accounting Policies [Line Items]
Accrued expenses and other current liabilities				100,000
Payable and accrued liabilities due to related party				$ 100,000

Acquisition of Assets and Ownership - Additional Information (Details) - ScalmiBio, Inc - USD ($)		12 Months Ended
	Oct. 04, 2021	Dec. 31, 2021
Business Acquisition [Line Items]
Business acquisition, initial payment in cash	$ 4,500,000
Business acquisition, addition payment of post-acquisition compensation costs	$ 2,000,000.0
Business acquisition, date of acquisition	Oct. 04, 2021
Maximum milestones amount payable on clinical development acquired technology	$ 35,000,000.0
Business acquisition, percentage of voting interests acquired	31.70%
Repayment of note and accrued interest	$ 87,000
Acquisition related costs		$ 200,000
Research and Development
Business Acquisition [Line Items]
Acquisition related costs		$ 4,700,000

Fair Value of Financial Instruments - Financial Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) - Fair Value on Recurring Basis - Money Market Funds - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Financial assets
Cash equivalents	$ 357,181	$ 424,115
Level 1
Financial assets
Cash equivalents	$ 357,181	$ 424,115

Fair Value of Financial Instruments - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value assets transferred from level 1 to level 2	$ 0	$ 0
Fair value assets transferred from level 2 to level 1	0	0
Fair value liabilities transferred from level 1 to level 2	0	0
Fair value liabilities transferred from level 2 to level 1	0	0
Fair value assets transferred into level 3	0	0
Fair value assets transferred out of level 3	0	0
Fair value liabilities transferred into level 3	0	0
Fair value liabilities transferred out of level 3	0	0
Fair Value on Recurring Basis
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Financial liabilities fair value disclosure	$ 0	$ 0

Balance Sheet Components - Schedule of Components of Property and Equipment (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 960	$ 77
Less: accumulated depreciation and amortization	(63)	(25)
Property and equipment, net	897	52
Laboratory Equipment
Property Plant And Equipment [Line Items]
Property and equipment, gross	324
Computer Hardware and Software
Property Plant And Equipment [Line Items]
Property and equipment, gross	241	63
Leasehold Improvements
Property Plant And Equipment [Line Items]
Property and equipment, gross	229	5
Furniture and Fixtures
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 166	$ 9

Balance Sheet Components - Additional Information (Details) - USD ($) $ in Millions	1 Months Ended	12 Months Ended
	Jul. 31, 2020	Dec. 31, 2020	Dec. 31, 2019
Schedule Of Balance Sheet Components [Line Items]
Depreciation and amortization expense		$ 0.2	$ 0.4
Lab Equipment and Other Assets
Schedule Of Balance Sheet Components [Line Items]
Proceeds from transfer of assets	$ 0.6

Balance Sheet Components - Schedule of Components of Other Assets, Net (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Property Plant And Equipment [Line Items]
Other assets	$ 12,267	$ 10
Long-term Prepaid Clinical Expenses
Property Plant And Equipment [Line Items]
Other assets	6,694
Long-term Prepaid Contract Manufacturing Costs
Property Plant And Equipment [Line Items]
Other assets	2,854
Operating Lease Right-of-use Assets
Property Plant And Equipment [Line Items]
Other assets	1,829
Finance Lease Right-of-use Assets
Property Plant And Equipment [Line Items]
Other assets	746
Deposits
Property Plant And Equipment [Line Items]
Other assets	$ 144	$ 10

Balance Sheet Components - Components of Accrued Expenses and Other Current Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Balance Sheet Related Disclosures [Abstract]
Accrued clinical and nonclinical study costs	$ 4,125	$ 1,401
Accrued compensation and related expenses	3,294	1,974
Accrued professional fees	790	300
Accrued contract manufacturing	693	2,123
Finance lease liabilities, current	429
Operating lease liabilities, current	313
Other	257	151
Accrued federal income tax		179
Total accrued expenses and other current liabilities	$ 9,901	$ 6,128

Leases - Additional Information (Details) $ in Thousands	1 Months Ended	12 Months Ended
Leases - Additional Information (Details) $ in Thousands	May 31, 2021 USD ($) ft²	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2017
Lessee Lease Description [Line Items]
Operating lease ROU assets		$ 1,800
Operating lease liabilities		$ 2,015
Option to extend term		no
Finance lease ROU assets		$ 700
Office Space at 866 Malcolm Road, Burlingame, California
Lessee Lease Description [Line Items]
Lessee, operating lease term of contract					5 years 4 months
Lessee, operating lease commencing end date					May 31, 2023
Operating lease ROU assets		200
Operating lease liabilities		200
Rent expense			$ 600	$ 800
Office Space at 323 Allerton Avenue, South San Francisco, California
Lessee Lease Description [Line Items]
Lessee, operating lease commencing end date	Aug. 31, 2026
Operating lease ROU assets	$ 2,000	1,600
Operating lease liabilities		$ 1,800
Area of operating lease \| ft²	10,000
Operating lease, description		Company entered into a lease agreement for office space totaling approximately 10,000 square feet at 323 Allerton Avenue, South San Francisco, California. The term of the lease is from July 5, 2021 to August 31, 2026, with early entry date of June 6, 2021. The lease does not provide an option to extend after it expires. The total lease payments for the life of the lease is approximately $2.0 million. The Company obtained the right to direct the usage of the office space on the early entry date, and therefore considered June 6, 2021 as the lease commencement date.
Existence of option to extend	false
Lessee, operating lease early entry date	Jun. 06, 2021
Option to extend term	no

Leases - Schedule of Maturities of Operating and Finance Lease Liabilities (Details) $ in Thousands	Dec. 31, 2021 USD ($)
Lessee, Operating Lease, Liability, Payment, Due [Abstract]
2022	$ 519
2023	482
2024	433
2025	446
Thereafter	301
Total lease payments	2,181
Less: imputed interest	(166)
Operating lease liabilities	2,015
Lease liabilities: current	457
Lease liabilities: non-current	1,558
Total lease liabilities	$ 2,015
Weighted average remaining lease term (in years)	4 years 3 months 18 days
Weighted average discount rate	3.50%
Finance Lease, Liability, Payment, Due [Abstract]
2022	$ 432
2023	288
Total lease payments	720
Less: imputed interest	(11)
Finance lease liabilities	709
Finance lease liabilities, current	429
Finance leases: non-current	280
Total lease liabilities	$ 709
Weighted average remaining lease term (in years)	1 year 8 months 12 days
Weighted average discount rate	1.70%

Leases - Schedule of Maturities of Operating and Finance Lease Liabilities (Parenthetical) (Details) $ in Thousands	Dec. 31, 2021 USD ($)
Lessee Lease Description [Line Items]
Operating current lease liabilities	$ 457
Finance current lease liabilities	429
Finance non-current lease liabilities	280
Tallac Therapeutics
Lessee Lease Description [Line Items]
Finance non-current lease liabilities	100
Accrued Expenses and Other Current Liabilities and Payable and Accrued Liabilities Due to Related Party
Lessee Lease Description [Line Items]
Operating current lease liabilities	700
Finance current lease liabilities	$ 100

Leases - Components of Lease Costs (Details) $ in Thousands	12 Months Ended
Leases - Components of Lease Costs (Details) $ in Thousands	Dec. 31, 2021 USD ($)
Leases [Abstract]
Operating lease cost	$ 360
Variable lease cost and other, net	84
Finance lease cost, Amortization of right-of-use assets	369
Finance lease cost, Interest	13
Total lease cost	$ 826

Leases - Supplemental Cash Flow Information Related to Leases (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2021 USD ($)
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows from operating leases	$ 243
Operating cash flows from finance leases	11
Financing cash flows from finance leases	281
Right-of-use asset acquired under leases
Operating leases	1,780
Finance leases	$ 776

Leases - Schedule of Future Minimum Lease Commitments under Operating Leases (Details) $ in Thousands	Dec. 31, 2020 USD ($)
Leases [Abstract]
2021	$ 140
2022-2023	206
Total future minimum lease payments	$ 346

Term Loan - Additional Information (Details) - USD ($)	12 Months Ended
Term Loan - Additional Information (Details) - USD ($)	Dec. 31, 2020	Dec. 31, 2021	Dec. 20, 2019
Debt Instrument [Line Items]
Increase in fair value of warrant liability	$ 8,000
Compound Derivative Liability
Debt Instrument [Line Items]
Fair value of compound derivative liability		$ 51,000
Increase in fair value of compound derivative liability	$ 658,000
Series B Convertible Preferred Stock
Debt Instrument [Line Items]
Warrant liability converted into common stock		$ 400,000
Loan Agreement
Debt Instrument [Line Items]
Term loan, principal amount			$ 6,000,000.0

Stockholders' Equity - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands			1 Months Ended	12 Months Ended
	Jul. 21, 2020	Jul. 20, 2020	Dec. 31, 2020	Dec. 31, 2021	Dec. 31, 2020	Jul. 31, 2020
Class Of Stock [Line Items]
Common stock, shares authorized	1,000,000,000		1,000,000,000	1,000,000,000	1,000,000,000
Common stock, shares outstanding			39,844,522	40,587,067	39,844,522
Underwriting discounts and commissions paid					$ 3,848
Common Stock
Class Of Stock [Line Items]
Issuance of common stock in connection with equity offerings, net of underwriter discounts and issuance costs, shares					12,512,000
Initial Public Offering \| Common Stock
Class Of Stock [Line Items]
Issuance of common stock in connection with equity offerings, net of underwriter discounts and issuance costs, shares	9,775,000
Net proceeds from initial public offering	$ 169,500
Underwriting discounts and commissions paid	13,000
Payment for offering related expense	$ 3,200
Convertible shares converted in to common stock	23,934,533					23,934,533
Follow-on Public Offering \| Common Stock
Class Of Stock [Line Items]
Issuance of common stock in connection with equity offerings, net of underwriter discounts and issuance costs, shares			2,737,000
Net proceeds from initial public offering			$ 194,900
Underwriting discounts and commissions paid			12,500
Payment for offering related expense			$ 700
Undesignated Preferred Stock
Class Of Stock [Line Items]
Convertible preferred stock, shares authorized	100,000,000
Convertible Preferred Stock
Class Of Stock [Line Items]
Preferred stock, cumulative dividends percentage				6.00%
Accrued cumulative dividends on the Series A, Series B and Series C convertible preferred stock		$ 18,000
Cumulative preferred stock dividend convertible shares issued upon conversion		2,564,759
Series A Convertible Preferred Stock
Class Of Stock [Line Items]
Shares original issue price				$ 6.58
Series B and C Convertible Preferred Stock
Class Of Stock [Line Items]
Shares original issue price				$ 9.4972

Stockholders' Equity - Common Stock Reserved for Future Issuance (Details)	Dec. 31, 2021 shares
Class Of Stock [Line Items]
Common stock reserved for future issuance	9,342,434
Stock Options Issued and Outstanding
Class Of Stock [Line Items]
Common stock reserved for future issuance	5,128,639
Restricted Stock Units Issued and Outstanding
Class Of Stock [Line Items]
Common stock reserved for future issuance	15,075
Remaining Shares Available for Future Issuance Under Equity Incentive Plan
Class Of Stock [Line Items]
Common stock reserved for future issuance	3,407,898
Employee Stock Purchase Plan Shares Authorized for Future Issuance
Class Of Stock [Line Items]
Common stock reserved for future issuance	790,822

Stock-Based Compensation - Additional Information (Details) - USD ($)		1 Months Ended	12 Months Ended
	Jan. 01, 2021	Jul. 31, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2015	Apr. 01, 2020
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock reserved for future issuance			9,342,434
Unvested early exercised options			0	63
Liability related to these unvested options			$ 0	$ 0
Stock-based compensation expenses			13,914,000	5,436,000	$ 297,000
Total intrinsic value of options exercised			$ 48,100,000	$ 4,400,000
Weighted-average grant-date fair value per share			$ 42.29	$ 7.74	$ 1.27
Unrecognized share-based compensation expense			$ 68,700,000
Unrecognized share-based compensation expense, weighted-average period			2 years 9 months 18 days
ESPP
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock reserved for future issuance		400,000	790,822
Percentage of eligible compensation withheld		15.00%
Share-based compensation, authorized amount		$ 25,000
Share-based compensation, number of shares authorized		3,000
Share-based Compensation, lower of closing price, percentage		85.00%
Maximum percentage of additional shares reserved for future issuance			1.00%
Number of additional shares reserved for future issuance	398,445
Number of shares purchased			7,623
Restricted Stock Units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of share option			15,075
Weighted-average grant-date fair value per share, restricted stock			$ 58.56
Restricted stock units granted			15,075	0	0
Unrecognized share-based compensation expense			$ 800,000
Unrecognized share-based compensation expense, weighted-average period			3 years 7 months 6 days
Stock Option Modification
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expenses				$ 1,700,000
Maximum \| ESPP
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock reserved for future issuance			800,000
2015 Share Award Scheme \| Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share option granted during the period						2,143,117
2020 Equity Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of share option							4,379,139
2020 Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock reserved for future issuance		7,874,862
Share options, maximum term			10 years
Share options, service period			4 years

Stock-Based Compensation - Summary of Shares Available for Grant (Details)	12 Months Ended
	Dec. 31, 2021 shares
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Shares Available to Grant Balance	2,835,445
Shares Available to Grant, Authorized	1,593,781
Shares Available to Grant, Granted	(1,447,470)
Shares Available to Grant, Canceled/forfeited	426,142
Shares Available to Grant Balance	3,407,898

Stock-Based Compensation - Summary of Stock 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]
Number of Options, Balance	4,857,308
Number of Options, Granted	1,432,395
Number of Options, Exercised	(734,922)
Number of Options, Canceled/forfeited	(426,142)
Number of Options, Balance	5,128,639	4,857,308
Number of Options, Exercisable at December 31, 2021	3,143,797
Weighted Average Exercise Price, Balance	$ 8.94
Weighted Average Exercise Price, Granted	60.21
Weighted Average Exercise Price, Exercised	3.47
Weighted Average Exercise Price, Canceled/forfeited	10.62
Weighted Average Exercise Price, Balance	23.91	$ 8.94
Weighted Average Exercise Price, Exercisable at December 31, 2021	$ 7.88
Weighted Average Remaining Contractual Life (Years), Outstanding Options	8 years 3 months 10 days	8 years 10 months 9 days
Weighted Average Remaining Contractual Life (Years), Outstanding Options Exercisable	7 years 7 months 28 days
Outstanding Options Aggregate Intrinsic Value, Balance	$ 49,745	$ 375,270
Outstanding Options Aggregate Intrinsic Value, Exercisable	$ 48,625

Stock-Based Compensation - Schedule of Fair Value of Each Option Grant Using Black-Scholes Option-Pricing Model (Details)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Risk-free interest rate, minimum	0.80%	0.30%	1.70%
Risk-free interest rate, maximum	1.40%	0.80%	2.10%
Expected dividend rate	0.00%	0.00%	0.00%
Expected stock price volatility, minimum	79.70%	78.70%	75.20%
Expected stock price volatility, maximum	86.90%	89.00%	80.50%
Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected term (in years)	5 years 3 months 18 days	5 years 9 months 18 days	4 years 4 months 24 days
Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected term (in years)	6 years 1 month 6 days	6 years 1 month 6 days	6 years

Stock-Based Compensation - Summary of Restricted Stock Unit Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Aggregate Intrinsic Value, Balance	$ 49,745	$ 375,270
Restricted Stock Units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of RSUs, Granted	15,075	0	0
Number of RSUs, Balance	15,075
Weighted-Average Grant Date Fair Value, Granted	$ 58.56
Weighted-Average Grant Date Fair Value, Balance	$ 58.56
Weighted Average Remaining Contractual Life (Years), Balance	1 year 9 months 29 days
Aggregate Intrinsic Value, Balance	$ 324

Stock-Based Compensation - Summary of Share-Based Compensation Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock-based compensation expense	$ 13,914	$ 5,436	$ 297
Research and Development
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock-based compensation expense	5,211	2,551	105
General and Administrative
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock-based compensation expense	$ 8,703	$ 2,885	33
Cost of Services for Related-party Revenue
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock-based compensation expense			$ 159

Income Taxes - Domestic and International Components of Pre-Tax Loss (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Income Tax Disclosure [Abstract]
United States	$ (30,565)	$ (9,457)	$ 813
International	(52,919)	(36,042)	(20,022)
Loss before income taxes	$ (83,484)	$ (45,499)	$ (19,209)

- Definition

Amount of income (loss) from continuing operations, including income (loss) from equity method investments, before deduction of income tax expense (benefit), and income (loss) attributable to noncontrolling interest.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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+ Details

Income Taxes - Schedule of Provision (Benefit) for Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Current provision for income taxes:
Federal	$ (21)	$ 239	$ 33
State		2	1
Total current	(21)	241	34
Deferred tax provision:
Provision for income taxes	$ (21)	$ 241	$ 34

- Definition

Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

+ References + Details

Income Taxes - Schedule of Statutory and Effective Income Tax Rate Reconciliation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Income Tax Disclosure [Abstract]
At federal statutory income tax rate	$ (17,532)	$ (9,555)	$ (4,034)
State income taxes	(105)	(3,098)	(1,875)
Stock-based compensation	(4,031)	(5)	60
Research & Development credits	(2,131)	(512)	(861)
Change in valuation allowance	11,476	5,710	3,733
Other	172	321	75
Foreign rate differential	11,032	7,380	3,886
Prior period true ups	1,098		(950)
Provision for income taxes	$ (21)	$ 241	$ 34

Income Taxes - Significant Components of Deferred Tax Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Deferred tax assets:
Loss carryforwards	$ 15,407	$ 7,283
Research & other credits	5,325	2,861
Other	16	76
Accrued expenses	529	383
Stock options	1,530	696
Lease Liabilities	542
Total deferred tax assets	23,349	11,299
Deferred tax liabilities:
Fixed assets	73	11
Lease ROU assets	541
Total deferred tax liabilities	614	11
Valuation allowance	(22,735)	(11,288)
Net deferred tax assets	$ 0	$ 0

Income Taxes - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Deferred tax assets, increase in valuation allowance	$ 11,400,000	$ 4,600,000
Unrecognized tax benefits	1,217,000	842,000	$ 692,000	$ 418,000
Recognized interest and penalties expense (benefit) related to unrecognized tax benefits	$ 0	$ 0	$ 0

Income Taxes - Schedule of Net Operating Losses and Tax Credit Carryforwards (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2021 USD ($)
Federal
Net Operating Loss And Tax Credit Carryforwards [Line Items]
Net operating losses	$ 47,142
Tax credits	$ 3,885
Federal \| Minimum
Net Operating Loss And Tax Credit Carryforwards [Line Items]
Tax credits, Expiration Years	2039
Federal \| Maximum
Net Operating Loss And Tax Credit Carryforwards [Line Items]
Tax credits, Expiration Years	2041
State
Net Operating Loss And Tax Credit Carryforwards [Line Items]
Net operating losses	$ 68,993
Tax credits	$ 3,236
State \| Minimum
Net Operating Loss And Tax Credit Carryforwards [Line Items]
Net operating losses, Expiration Years	2038
State \| Maximum
Net Operating Loss And Tax Credit Carryforwards [Line Items]
Net operating losses, Expiration Years	2040
Foreign
Net Operating Loss And Tax Credit Carryforwards [Line Items]
Net operating losses	$ 5,509

Income Taxes - Schedule of Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Balance at beginning of year	$ 842	$ 692	$ 418
Additions/reversals based on tax positions of prior years	(69)	(64)	2
Additions based on tax positions related to the current year	494	240	272
Lapses in statutes of limitations	(50)	(26)
Balance at end of year	$ 1,217	$ 842	$ 692

Related-Party Transactions - Additional Information (Details) $ in Thousands		1 Months Ended		12 Months Ended
	Jul. 01, 2020	Jul. 31, 2020 USD ($)	Jun. 30, 2018	Dec. 31, 2021 USD ($) Investor	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Oct. 04, 2021
Related Party Transaction [Line Items]
Related-party revenue					$ 1,182	$ 4,796
Research and development costs				$ 60,170	28,961	16,306
Lab Equipment and Other Assets
Related Party Transaction [Line Items]
Proceeds from transfer of assets		$ 600
ScalmiBio, Inc
Related Party Transaction [Line Items]
Business acquisition, percentage of voting interests acquired							31.70%
Tallac Therapeutics \| Lab Equipment and Other Assets
Related Party Transaction [Line Items]
Proceeds from transfer of assets		$ 600
Research and Development Services Agreement \| Tollnine
Related Party Transaction [Line Items]
Number of company's investors who are investors in related party as well \| Investor				2
Related-party revenue				$ 0	1,200	$ 4,800
Initial term of agreement with related party			3 years
Markup cost in percentage			10.00%
Research and Development Services Agreement \| Tallac Therapeutics
Related Party Transaction [Line Items]
Initial term of agreement with related party	4 years
Markup cost in percentage	10.00%
Agreement automatically renewal additional term unless terminated	1 year
Research and development costs				800	$ 600
Collaboration Agreement \| Tallac Therapeutics
Related Party Transaction [Line Items]
Research and development costs				2,800
Accrued expenses due				$ 1,400

Net Loss Per Share Attributable to Common Stockholders - Computation of Basic and Diluted Net Loss per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Numerator:
Net loss	$ (83,463)	$ (45,740)	$ (19,243)
Less: cumulative preferred dividends allocated to preferred stockholders		(5,202)	(4,028)
Net loss attributable to common stockholders	$ (83,463)	$ (50,942)	$ (23,271)
Denominator:
Weighted-average shares of common stock outstanding	40,308,050	18,485,343	3,076,461
Net loss per share attributable to common stockholders, basic and diluted	$ (2.07)	$ (2.76)	$ (7.56)

- Definition

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

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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- Definition

Amount, after deduction of tax, noncontrolling interests, dividends on preferred stock and participating securities; of income (loss) available to common shareholders.

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+ Details

Net Loss Per Share Attributable to Common Stockholders - Summary of Outstanding Potentially Dilutive Securities Were Excluded from Computation of Diluted Net Loss Per Share (Details) - shares	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share	5,143,714	4,857,371	11,592,869
Convertible Preferred Stock
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share			10,313,808
Warrants to Purchase Convertible Preferred Stock
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share			61,292
Common Stock Subject to Repurchase
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share		63	34,024
Options Issued and Outstanding
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share	5,128,639	4,857,308	1,183,745
Restricted Stock Units Issued and Outstanding
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share	15,075

Commitments and Contingencies - Additional Information (Details) $ in Millions	12 Months Ended
	Dec. 31, 2021 USD ($)
Exclusive Equity Agreement
Commitments And Contingencies [Line Items]
Nonrefundable license royalty and patent expenses	$ 0.1
Clinical and regulatory milestones payments	5.0
Milestone payments related to clinical and regulatory	0.2
Commercial License Agreement
Commitments And Contingencies [Line Items]
Clinical and regulatory milestones payments	1.2
Milestone payments related to clinical and regulatory	0.1
Commercial Antibody Agreement
Commitments And Contingencies [Line Items]
Clinical and regulatory milestones payments	11.1
Milestone payments related to clinical and regulatory	$ 0.0

Commitments and Contingencies - Summary of Company's Commitments and Contractual Obligations (Details) $ in Thousands	Dec. 31, 2021 USD ($)
Commitments And Contingencies Disclosure [Abstract]
Total lease payments	$ 2,181
Operating lease obligations, 2022	519
Operating lease obligations, 2023 - 2024	915
Operating lease obligations, 2025 - 2026	747
Total lease payments	720
Finance lease obligations, 2022	432
Finance lease obligations, 2023 - 2024	288
Manufacturing and service contracts, Total	21,211
Manufacturing and service contracts, 2022	17,578
Manufacturing and service contracts, 2023 - 2024	3,550
Manufacturing and service contracts, 2025 - 2026	83
Contractual Obligation, Total	24,112
Contractual Obligation, 2022	18,529
Contractual Obligation, 2023 - 2024	4,753
Contractual Obligation, 2025 - 2026	$ 830

Commitments and Contingencies - Summary of Company's Commitments and Contractual Obligations (Parenthetical) (Details) - USD ($)	1 Months Ended	12 Months Ended
	Nov. 30, 2015	Dec. 31, 2021
Commitments And Contingencies [Line Items]
Contractual Obligation		$ 24,112,000
Future purchase obligations		21,211,000
Indemnification Agreement
Commitments And Contingencies [Line Items]
Contractual Obligation		$ 0
Master Service Agreement
Commitments And Contingencies [Line Items]
Initial term of agreement	3 years
Renewal periods of agreement	1 year
Future purchase obligations	$ 20,700,000
Office and Laboratory Space \| Burlingame, California
Commitments And Contingencies [Line Items]
Operating sub-lease expiration year		2023
Office and Laboratory Space \| South San Francisco, California
Commitments And Contingencies [Line Items]
Operating sub-lease expiration year		2026
Second Drug Product Manufacturer \| Master Service Agreement
Commitments And Contingencies [Line Items]
Future purchase obligations	$ 500,000

Subsequent Event - Additional Information (Details) - Office and Laboratory Space Located In Palo Alto, California - Subsequent Event $ in Millions	Feb. 07, 2022 USD ($) ft²
Subsequent Event [Line Items]
Area of operating lease \| ft²	11,074
Lessee, operating lease term of contract	96 months
Lease operating lease commencement period	2022-02
Lease operating lease not yet commenced, commencement period	2022-10
Annual base rent	$ 0.8
Annual increase in rent percentage	3.00%
Total lease payment	$ 7.0
Tenant improvement allowance	$ 1.5