BioAtla (BCAB) 10-K 23 Mar 23 2022 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Mar. 16, 2023	Jun. 30, 2022
Document Information [Line Items]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2022
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	FY
Document Annual Report	true
Document Transition Report	false
Entity Interactive Data Current	Yes
Entity Incorporation, State or Country Code	DE
Entity Registrant Name	BIOATLA, INC.
Entity Central Index Key	0001826892
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Title of 12(b) Security	Common Stock, $0.0001 par value per share
Trading Symbol	BCAB
Security Exchange Name	NASDAQ
Entity Public Float			$ 69
Entity Current Reporting Status	Yes
Entity Shell Company	false
Entity File Number	001-39787
Entity Tax Identification Number	85-1922320
Entity Address, Address Line One	11085 Torreyana Road
Entity Address, City or Town	San Diego
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	92121
City Area Code	858
Local Phone Number	558-0708
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
ICFR Auditor Attestation Flag	false
Documents Incorporated by Reference	DOCUMENTS INCORPORATED BY REFERENCE Part III incorporates by reference certain information from the registrant’s definitive proxy statement (the “Proxy Statement”) relating to its 2023 Annual Meeting of Stockholders. The Proxy Statement will be filed with the United States Securities and Exchange Commission within 120 days after the end of the fiscal year to which this report relates.
Auditor Name	Ernst & Young LLP
Auditor Location	San Diego, CaliforniaMarch
Auditor Firm ID	42
Common Stock
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		47,607,133
Common Class B
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		0

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Current assets:
Cash and cash equivalents	$ 215,507	$ 244,979
Prepaid expenses and other current assets	4,924	2,313
Total current assets	220,431	247,292
Property and equipment, net	2,728	3,676
Operating lease right-of-use-asset, net	2,423	3,300
Other assets	154	154
Total assets	225,736	254,422
Current liabilities:
Accounts payable and accrued expenses	21,610	18,424
Operating lease liabilities	1,521	1,389
Total current liabilities	23,131	19,813
Operating lease liabilities, less current portion	2,460	3,982
Liability to licensor	19,806	19,806
Total liabilities	45,397	43,601
Commitments and contingencies (Note 6)
Stockholders' equity:
Preferred stock, $0.0001 par value; 200,000,000 shares authorized at December 31, 2022 and December 31, 2021; 0 shares issued and outstanding at December 31, 2022 and December 31, 2021
Common stock value	5	4
Additional paid-in capital	473,135	397,136
Accumulated deficit	(292,801)	(186,319)
Total stockholders' equity	180,339	210,821
Total liabilities and stockholders' equity	225,736	254,422
Common Class B
Stockholders' equity:
Common stock value

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2022	Dec. 31, 2021
Preferred Stock, Par or Stated Value Per Share	$ 0.0001	$ 0.0001
Preferred Stock, Shares Authorized	200,000,000	200,000,000
Preferred Stock, Shares Issued	0	0
Preferred Stock, Shares Outstanding	0	0
Common Stock, Par or Stated Value Per Share	$ 0.0001	$ 0.0001
Common Stock, Shares Authorized	350,000,000	350,000,000
Common Stock, Shares, Issued	46,336,166	35,799,233
Common Stock, Shares, Outstanding	46,336,166	35,799,233
Common Class B
Common Stock, Par or Stated Value Per Share	$ 0.0001	$ 0.0001
Common Stock, Shares Authorized	15,368,569	15,368,569
Common Stock, Shares, Issued	1,211,959	1,492,059
Common Stock, Shares, Outstanding	1,211,959	1,492,059

Consolidated Statements of Oper

Consolidated Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Collaboration and other revenue	$ 0	$ 250
Operating expenses:
Research and development expense	79,347	58,274
General and administrative expense	28,793	38,416
Total operating expenses	108,140	96,690
Loss from operations	(108,140)	(96,440)
Other income (expense):
Interest income	1,648	350
interest expense	0	(3)
Gain on extinguishment of long-term debt	0	690
Other income (expense)	10	1
Total other income (expense)	1,658	1,038
Consolidated net loss and comprehensive loss	$ (106,482)	$ (95,402)
Net loss per common share, basic	$ (2.74)	$ (2.76)
Net loss per common share, diluted	$ (2.74)	$ (2.76)
Weighted-average shares of common stock outstanding, basic	38,927,268	34,561,245
Weighted-average shares of common stock outstanding, diluted	38,927,268	34,561,245

Consolidated Statements of Conv

Consolidated Statements of Convertible Preferred Stock and Stockholders / Members Equity (Deficit) - USD ($) $ in Thousands	Total	Class B Common Stock	Common Stock	Additional Paid-in Capital	Retained Earnings
Balance at Dec. 31, 2020	$ 209,974		$ 3	$ 300,888	$ (90,917)
Balance, shares at Dec. 31, 2020		1,492,059	32,171,560
Issuance of common stock under equity incentive plans, shares			930,144
Issuance of common stock upon exercise of options, net	$ 140			140
Issuance of common stock upon exercise of options, net, shares	7,747		7,747
Issuance of common stock for Employee Stock Purchase Plan	$ 289			289
Issuance of common stock for Employee Stock Purchase Plan, shares			11,182
Issuance of common stock, net of issuance costs	70,994		$ 1	70,993
Issuance of common stock, net of issuance costs, shares			2,678,600
Taxes related to net share settlement of equity awards	(291)			(291)
Stock-based compensation	25,117			25,117
Net loss	(95,402)				(95,402)
Balance at Dec. 31, 2021	$ 210,821		$ 4	397,136	(186,319)
Balance, shares at Dec. 31, 2021		1,492,059	35,799,233
Issuance of common stock under equity incentive plans, shares			364,141
Issuance of common stock upon exercise of options, net, shares	0
Issuance of common stock for Employee Stock Purchase Plan	$ 289			289
Issuance of common stock for Employee Stock Purchase Plan, shares			147,564
Issuance of common stock, net of issuance costs	61,682		$ 1	61,681
Issuance of common stock, net of issuance costs, shares			9,745,128
Taxes related to net share settlement of equity awards	(534)			(534)
Conversion of Class B Common Stock		(280,100)	280,100
Stock-based compensation	14,563			14,563
Net loss	(106,482)				(106,482)
Balance at Dec. 31, 2022	$ 180,339		$ 5	$ 473,135	$ (292,801)
Balance, shares at Dec. 31, 2022		1,211,959	46,336,166

Consolidated Statements of Co_2

Consolidated Statements of Convertible Preferred Stock and Stockholders / Members Equity (Deficit) (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Payments of Stock Issuance Costs	$ 3,318	$ 4,007

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Cash flows from operating activities
Net loss	$ (106,482)	$ (95,402)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	1,199	1,330
Loss on disposal of property and equipment	13	4
Gain on extinguishment of debt	0	(690)
Stock-based compensation	14,563	25,117
Accrued interest	0	3
Changes in operating assets and liabilities:
Prepaid expenses and other assets	(2,611)	(237)
Accounts payable and accrued expenses	3,411	7,992
Right-of-use assets and lease liabilities, net	(513)	(331)
Net cash used in operating activities	(90,420)	(62,214)
Cash flows from investing activities
Purchases of property and equipment	(268)	(924)
Proceeds from sale of property and equipment	3	0
Net cash used in investing activities	(265)	(924)
Cash flows from financing activities
Payment of initial public offering costs	0	(1,911)
Proceeds from issuance of common stock, net of issuance costs	61,682	70,994
Proceeds from exercise of stock options	0	140
Proceeds from issuance of common stock under Employee Stock Purchase Plan	289	289
Payments for taxes related to net settlement of equity awards	(758)	0
Net cash provided by financing activities	61,213	69,512
Net increase (decrease) in cash and cash equivalents	(29,472)	6,374
Cash and cash equivalents, beginning of period	244,979	238,605
Cash and cash equivalents, end of period	215,507	244,979
Supplemental disclosure of non-cash investing and financing activities
Property and equipment additions included in accounts payable and accrued expenses	1	1
Tax related to net settlement of equity award included in accounts payable and accrued expenses	$ 67	$ 291

Organization and summary of sig

Organization and summary of significant accounting policies	12 Months Ended
	Dec. 31, 2022
Accounting Policies [Abstract]
Organization and summary of significant accounting policies	1. Organization and summary of significant accounting policies Organization BioAtla, LLC was formed in Delaware in March 2007 and was converted to a Delaware corporation in July 2020 and renamed BioAtla, Inc. (the “Company”). The Company has a proprietary platform for creating biologics, including its conditionally active biologics (“CAB” or “CABs”). CABs have been designed to be active only under certain conditions found in diseased tissue, while remaining inactive in normal tissue. The Company is currently in clinical development of its two lead CAB antibody drug conjugates (“CAB ADC”) targeting AXL and ROR2 receptors, and its CAB immune-oncology antibody targeting CTLA-4. Basis of Presentation The accompanying consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”). BioAtla, Inc. is a single legal entity with no consolidated variable interest entities ("VIEs") or subsidiaries (see Note 9). Liquidity and Going Concern The Company has incurred cumulative operating losses and negative cash flows from operations since its inception and expects to continue to incur significant expenses and operating losses for the foreseeable future as it continues the development of its product candidates. As of December 31, 2022, the Company had an accumulated deficit of $ 292.8 million . The Company plans to continue to fund its losses from operations and capital funding needs through public or private equity or debt financings, or other sources. If the Company is not able to secure adequate additional funding, the Company may be forced to make reductions in spending, extend payment terms with suppliers, liquidate assets where possible, or suspend or curtail planned programs. Any of these actions could materially harm the Company’s business, results of operations and future prospects. Management is required to perform a two-step analysis of the Company’s ability to continue as a going concern. Management must first evaluate whether there are conditions and events that raise substantial doubt about the Company’s ability to continue as a going concern (Step 1). If management concludes that substantial doubt is raised, management is also required to consider whether its plans alleviate that doubt (Step 2). Management’s assessment included the preparation of cash flow forecasts resulting in management’s conclusion that there is not substantial doubt about the Company’s ability to continue as a going concern for 12 months after the date the consolidated financial statements for the year ended December 31, 2022 are issued. Variable Interest Entities The Company consolidates entities in which it has a controlling financial interest. The Company determines whether it has a controlling financial interest in an entity by first evaluating whether the entity is a voting interest entity or a variable interest entity (“VIE”). VIEs are entities in which (i) the total equity investment at risk is sufficient to enable the entity to finance its activities independently, (ii) the equity holders have the power to direct the activities of the entity that most significantly impact its economic performance, the obligation to absorb the losses of the entity and the right to receive the residual returns of the entity and (iii) the legal entity is structured with substantive voting rights. A VIE is an entity that lacks one or more of the characteristics of a voting interest entity. The Company has a controlling financial interest in a VIE when the Company has a variable interest or interests that provide it with (i) the power to direct the activities of the VIE that most significantly impact the VIE’s economic performance and (ii) the obligation to absorb losses of the VIE or the right to receive benefits from the VIE that could potentially be significant to the VIE. The Company evaluates its relationships with its VIEs on an ongoing basis to determine whether or not it has a controlling financial interest (see Note 9). Use of Estimates The Company’s consolidated financial statements are prepared in accordance with U.S. generally accepted accounting principles (“GAAP”). The preparation of the Company’s consolidated financial statements requires it to make estimates and assumptions that impact the reported amounts of assets, liabilities, revenues and expenses and the disclosure of contingent assets and liabilities in the Company’s consolidated financial statements and accompanying notes. The most significant estimates in the Company’s consolidated financial statements relate to revenue recognition, accruals for research and development costs, equity-based compensation and fair value measurements. These estimates and assumptions are based on current facts, historical experience and various other factors believed to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities and the recording of revenue and expenses that are not readily apparent from other sources. Actual results may differ materially and adversely from these estimates. To the extent there are material differences between the estimates and actual results, the Company’s future results of operations will be affected. Segment Reporting Operating segments are identified as components of an enterprise about which separate discrete financial information is available for evaluation by the chief operating decision-maker in making decisions regarding resource allocation and assessing performance. The Company views its operations and manages its business in one operating segment. Cash and Cash Equivalents The Company considers all highly liquid investments with original maturities of three months or less when purchased to be cash equivalents. Concentrations of Risk Financial instruments that potentially subject the Company to a significant 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. The Company has not experienced any losses in such accounts and management believes that the Company is not exposed to significant credit risk due to the financial position of the depository institutions in which those deposits are held. Property and Equipment Property and equipment are stated at cost and depreciated on a straight-line basis over the estimated useful life of the related assets. Leasehold improvements are stated at cost and amortized on a straight-line basis over the lesser of the remaining term of the related lease or the estimated useful life of the leasehold improvements. Repairs and maintenance costs are charged to expense as incurred and expenditures that materially extend the useful lives of assets are capitalized. Impairment of Long-Lived Assets The Company reviews long-lived assets, such as property and equipment, for impairment whenever events or changes in circumstances indicate the carrying amount of an asset may not be recoverable. Recoverability of assets to be held and used is measured by a comparison of the carrying amount of an asset to the future undiscounted net cash flows expected to be generated by the asset. 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 the fair value of the assets. Fair value would be assessed using discounted cash flows or other appropriate measures of fair value. The Company has no t recognized any impairment losses for the years ended December 31, 2022 and 2021 . Leases The Company determines if an arrangement is a lease at inception. An arrangement is or contains a lease if it conveys the right to control the use of an identified asset for a period of time in exchange for consideration. If a lease is identified, classification is determined at lease commencement. Operating lease liabilities are recognized at the present value of the future lease payments at the lease commencement date. The Company’s leases do not provide an implicit interest rate and therefore the Company estimates its incremental borrowing rate to discount lease payments. The incremental borrowing rate reflects the interest rate that the Company would have to pay to borrow on a collateralized basis an amount equal to the lease payments in a similar economic environment over a similar term. Operating lease right-of-use (“ROU”) assets are based on the corresponding lease liability adjusted for any lease payments made at or before commencement, initial direct costs, and lease incentives. Renewals or early terminations are not accounted for unless the Company is reasonably certain to exercise these options. Operating lease expense is recognized and the ROU asset is amortized on a straight-line basis over the lease term. Variable lease costs are not included in the calculation of the ROU asset and the related lease liability and are recognized as incurred. The Company has a single lease agreement with lease and non-lease components, which are accounted for as a single lease component. Lease payments for short-term leases, defined as leases with a term of twelve months or less, are expensed on a straight-line basis over the lease term. The Company does not currently have any short-term leases. Operating leases are included in operating lease right-of-use assets, operating lease liabilities, and operating lease liabilities, non-current on the Company’s consolidated balance sheets. The Company does not have any finance leases. Revenue Recognition The Company recognizes revenue in a manner that depicts the transfer of control of a product or a service to a customer and reflects the amount of the consideration the Company is entitled to receive in exchange for such product or service. In doing so, the Company follows a five-step approach: (i) identify the contract 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, and (v) recognize revenue when (or as) the customer obtains control of the product or service. The Company considers the terms of a contract and all relevant facts and circumstances when applying the revenue recognition standard. A customer is a party that has entered into a contract with the Company, where the purpose of the contract is to obtain a product or a service that is an output of the Company’s ordinary activities in exchange for consideration. To be considered a contract, (i) the contract must be approved (in writing, orally, or in accordance with other customary business practices), (ii) each party’s rights regarding the product or the service to be transferred can be identified, (iii) the payment terms for the product or the service to be transferred can be identified, (iv) the contract must have commercial substance (that is, the risk, timing or amount of future cash flows is expected to change as a result of the contract), and (v) it is probable that the Company will collect substantially all of the consideration to which it is entitled to receive in exchange for the transfer of the product or the service. A performance obligation is defined as a promise to transfer a product or a service to a customer. The Company identifies each promise to transfer a product or a service (or a bundle of products or services, or a series of products and services that are substantially the same and have the same pattern of transfer) that is distinct. A product or a service is distinct if both (i) the customer can benefit from the product or the service either on its own or together with other resources that are readily available to the customer and (ii) the Company’s promise to transfer the product or the service to the customer is separately identifiable from other promises in the contract. Each distinct promise to transfer a product or a service is a unit of accounting for revenue recognition. If a promise to transfer a product or a service is not separately identifiable from other promises in the contract, such promises should be combined into a single performance obligation. The transaction price is the amount of consideration the Company is entitled to receive in exchange for the transfer of control of a product or a service to a customer. To determine the transaction price, the Company considers the existence of any significant financing component, the effects of any variable elements, noncash consideration and consideration payable to the customer. If a significant financing component exists, the transaction price is adjusted for the time value of money. If an element of variability exists, the Company must estimate the consideration it expects to receive and uses that amount as the basis for recognizing revenue as the product or the service is transferred to the customer. There are two methods for determining the amount of variable consideration: (i) the expected value method, which is the sum of probability-weighted amounts in a range of possible consideration amounts, and (ii) the mostly likely amount method, which identifies the single most likely amount in a range of possible consideration amounts. If a contract has multiple performance obligations, the Company allocates the transaction price to each distinct performance obligation in an amount that reflects the consideration the Company is entitled to receive in exchange for satisfying each distinct performance obligation. For each distinct performance obligation, revenue is recognized when the Company transfers control of the product or the service applicable to such performance obligation. In those instances where the Company first receives consideration in advance of satisfying its performance obligation, the Company classifies such consideration as deferred revenue until (or as) the Company satisfies such performance obligation. In those instances where the Company first satisfies its performance obligation prior to its receipt of consideration, the consideration is recorded as accounts receivable. The Company expenses incremental costs of obtaining and fulfilling a contract as incurred if the expected amortization period of the asset that would be recognized is one year or less, or if the amount of the asset is immaterial. Otherwise, such costs are capitalized as contract assets if they are incremental to the contract and amortized to expense proportionate to revenue recognition of the underlying contract. Research and Development Expenses The Company’s activities have largely consisted of research and development efforts related to developing our CAB programs. Research and development expenses consist of expenses incurred in performing research and development activities including salaries and benefits, facilities and other overhead expenses, clinical trials, contract services and other outside expenses. Research and development expenses are charged to expense as incurred. Payments for these activities are based on the terms of the individual agreements, which may differ from the pattern of costs incurred, and are reflected in the accompanying consolidated balance sheets as prepaid or accrued expenses. When evaluating the adequacy of the accrued expenses, the Company analyzes progress of the services, including the phase or completion of events, invoices received and contracted costs. Significant judgments and estimates may be made in determining the accrued balances at the end of any reporting period. Actual results could differ from the Company’s estimates. As of December 31, 2022, the Company has accrued $ 5.5 million related to clinical trial costs. The Company has entered into contracts related to its clinical trials with clinical research organizations. The Company reviews and accrues clinical trial costs based on work performed, which relies on estimates of total trial management costs, sites activated, patients enrolled, and number of patient visits. The Company follows this method since reasonably dependable estimates of the costs applicable to clinical trials can be made. Accrued clinical trial costs are subject to revisions as the trials progress. Revisions are charged to expense in the period in which the facts that give rise to the revision become known. Historically, revisions have not resulted in material changes to research and development expense; however, a modification in the protocol of a clinical trial or cancellation of a trial could result in a change to the Company's results of operations. Patent Costs Costs related to filing and pursuing patent applications are recorded as general and administrative expenses and expensed as incurred since recoverability of such expenditures is uncertain. Stock-Based Compensation Stock-based compensation expense represents the grant date fair value of equity awards, consisting of stock options, restricted stock units (“RSUs”) and employee stock purchase plan rights, over the requisite service period of the awards (usually the vesting period) on a straight-line basis. The Company estimates the fair value of stock option grants and employee stock purchase plan rights using the Black-Scholes option pricing model. Prior to the Company’s IPO, the fair value of RSUs was based on the estimated fair value of the underlying common stock on the date of grant and, subsequent to the Company’s IPO, the fair value is based on the closing sales price of the Company’s common stock on the date of grant. Equity award forfeitures are recognized as they occur. 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 based on the differences between the financial statements and tax basis of assets and liabilities using enacted tax rates in effect for the year in which the differences are expected to reverse. The effect of a change in tax rates on deferred tax assets and liabilities is recognized as income in the period that includes the enactment date. The Company recognizes net deferred tax assets to the extent that the Company believes these assets are more likely than not to be realized. In making such a determination, management considers all available positive and negative evidence, including future reversals of existing taxable temporary differences, projected future taxable income, exclusive of reversing temporary difference, tax-planning strategies, and the results of recent operations. If management determines that the Company would be able to realize its deferred tax assets in the future in excess of their net recorded amount, management would make an adjustment to the deferred tax asset valuation allowance, which would reduce the provision for income taxes. The Company records uncertain tax positions on the basis of a two-step process whereby (1) management determines whether it is more likely than not that the tax positions will be sustained on the basis of the technical merits of the position and (2) for those tax positions that meet the more-likely-than-not recognition threshold, management recognizes the largest amount of tax benefit that is more than 50 % likely to be realized upon ultimate settlement with the related tax authority. The Company recognizes interest and penalties related to unrecognized tax benefits within income tax expense. Any accrued interest and penalties are included within the related tax liability. Comprehensive Loss Comprehensive loss is defined as a change in equity during a period from transactions and other events and circumstances from non-owner sources. There have been no items qualifying as other comprehensive loss and, therefore, for all periods presented, the Company’s comprehensive loss was the same as its reported net loss. Net Loss Per Share Basic net loss per common share is computed by dividing the net loss by the weighted-average number of common shares outstanding for the period, without consideration for potentially dilutive securities. Diluted net loss per share is computed by dividing the net loss by the weighted-average number of common shares and dilutive common stock equivalents outstanding for the period determined using the treasury-stock method. Dilutive common stock equivalents are comprised of RSUs, common stock options outstanding under the Company’s stock option plan, and contingently issuable shares under the Company's ESPP plan. Potentially dilutive securities not included in the calculation of diluted net loss per share because to do so would be anti-dilutive are as follows (in common stock equivalents): December 31, 2022 2021 Common stock warrants — 151,088 Common stock options 2,736,918 1,086,902 Restricted stock units 510,039 975,046 ESPP Shares 13,370 — Total 3,260,327 2,213,036 Recent Accounting Pronouncements There were no recently issued or effective FASB Accounting Standards Updates (ASUs) that had, or are expected to have, a material effect on the Company's results of operations, financial condition, or liquidity.

Balance sheet details

Balance sheet details	12 Months Ended
	Dec. 31, 2022
Balance Sheet Related Disclosures [Abstract]
Balance sheet details	2. Balance sheet details Prepaid expenses and other current assets consist of the following (in thousands): December 31, 2022 2021 Prepaid research and development $ 4,385 $ 1,811 Other prepaid expenses and current assets 539 502 Total $ 4,924 $ 2,313 Property and equipment consist of the following (in thousands): December 31, Useful life (years) 2022 2021 Furniture, fixtures and office equipment 3 - 7 $ 2,140 $ 2,123 Laboratory equipment 5 2,265 2,123 Leasehold improvements 2 - 3 3,687 3,687 8,092 7,933 Less accumulated depreciation and amortization ( 5,364 ) ( 4,257 ) Total $ 2,728 $ 3,676 Accounts payable and accrued expenses consist of the following (in thousands): December 31, 2022 2021 Accounts payable $ 4,231 $ 1,179 Accrued compensation 3,451 2,671 Accrued research and development 12,649 13,501 Other accrued expenses 1,279 1,073 Total $ 21,610 $ 18,424

Fair value measurements

Fair value measurements	12 Months Ended
	Dec. 31, 2022
Fair Value Disclosures [Abstract]
Fair value measurements	3. Fair value measurements The carrying amounts of the Company’s current financial assets and current financial liabilities are considered to be representative of their respective fair values because of the short-term nature of those instruments. As of December 31, 2022 and December 31, 2021 , the Company had no financial assets or liabilities measured at fair value on a recurring basis. The accounting guidance defines fair value, establishes a consistent framework for measuring fair value and expands disclosure for each major asset and liability category measured at fair value on either a recurring or non-recurring basis. Fair value is defined as an exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. As such, fair value is a market-based measurement that should be determined based on assumptions that market participants would use in pricing an asset or liability. As a basis for considering such assumptions, the accounting guidance establishes a three-tier fair value hierarchy, which prioritizes the inputs used in measuring fair value as follows: Level 1: Observable inputs such as quoted prices in active markets. Level 2: Inputs, other than the quoted prices in active markets that are observable either directly or indirectly. Level 3: Unobservable inputs in which there is little or no market data, which require the reporting entity to develop its own assumptions. None of the Company’s non-financial assets and liabilities are recorded at fair value on a non-recurring basis. No transfers between levels have occurred during the periods presented.

Debt

Debt	12 Months Ended
	Dec. 31, 2022
Debt Disclosure [Abstract]
Debt	4. Debt The Company did no t have any outstanding debt as of December 31, 2022 or December 31, 2021 . In April 2020, the Company borrowed $ 0.7 million under the Paycheck Protection Program (“PPP”) under the CARES Act. The loan was subsequently forgiven in July 2021. The $ 0.7 million balance of the forgiven loan was recognized as other income on the Company's Statement of Operations and Comprehensive Loss for the twelve months ended December 31, 2021 .

Leases

Leases	12 Months Ended
	Dec. 31, 2022
Leases [Abstract]
Leases	5. Leases The Company has a single operating lease for its corporate headquarters and laboratory space in San Diego, California. The lease expires in July 2025 and the Company has an option to extend the term of the lease for an additional five years . However, it is not reasonably certain the Company will exercise the option to renew when the lease term ends and thus, the incremental term was excluded from the calculation of the lease liability. Additionally, the lease includes certain rent abatement, rent escalations, tenant improvement allowances and additional charges for common area maintenance and other costs. The components of lease expense included in the Company’s consolidated statements of operations include (in thousands): Years ended December 31, 2022 2021 Operating lease expense $ 1,043 $ 1,043 Variable lease expense 460 512 Total lease expense, net $ 1,503 $ 1,555 Variable lease costs are primarily related to payments made to lessors for common area maintenance, property taxes, insurance, and other operating expenses. The Company did not have any short-term leases or finance leases for the year ended December 31, 2022. The weighted average remaining lease term and weighted average discount rate for operating leases as of December 31, 2022 were as follows: Years ended December 31, 2022 2021 Weighted average remaining lease term (in years) 2.5 3.5 Weighted average discount rate percentage 3.50 % 3.50 % Supplemental cash flow information related to leases under which the Company is the lessee was as follows (amounts in thousands): Years ended December 31, 2022 2021 Cash paid for amounts included in the measurement of operating leases $ 1,555 $ 1,374 Maturities of operating lease liabilities as of December 31, 2022 were as follows (in thousands): Years ending December 31: Operating 2023 $ 1,636 2024 1,685 2025 845 Thereafter — Total future lease payments 4,166 Less imputed interest ( 184 ) Total operating lease liabilities $ 3,982

Commitments and contingencies

Commitments and contingencies	12 Months Ended
	Dec. 31, 2022
Commitments and Contingencies Disclosure [Abstract]
Commitments and contingencies	6. Commitments and contingencies From time to time, the Company may be subject to various claims and suits arising in the ordinary course of business. The Company is not currently a party to any legal proceedings the outcome of which the Company believes, if determined adversely to the Company, would individually or in the aggregate have a material adverse effect on the Company’s business, operating results or financial condition.

Stockholders equity

Stockholders equity	12 Months Ended
	Dec. 31, 2022
Equity [Abstract]
Stockholders equity (deficit)	7. Stockholders’ equity Description of securities of Delaware corporation The Company is authorized to issue 200,000,000 shares of preferred stock, par value $ 0.0001 per share, 350,000,000 shares of common stock, par value $ 0.0001 per share, and 15,368,569 shares of Class B common stock, par value $ 0.0001 per share. Dividends Subject to preferences that may be applicable to any outstanding shares of preferred stock, holders of the Company’s common stock and Class B common stock are entitled to receive dividends only if declared from time to time by the Company’s board of directors out of assets which are legally available. Liquidation preferences Upon any liquidation, dissolution or winding-up of the Company, holders of the Company’s common stock and Class B common stock are entitled to share ratably in all assets remaining after payment of all liabilities and the liquidation preferences of any of our outstanding shares of preferred stock. Conversion Holders of the Company’s common stock have no conversion rights, while holders of the Company’s Class B common stock shall have the right to convert each share of Class B common stock into one share of common stock at such holder’s election, provided that as a result of such conversion, such holder would not beneficially own in excess of 4.99% of any class of the Company’s securities registered under the Securities Exchange Act of 1934 , as amended, unless otherwise as expressly provided for in the Company’s amended and restated certificate of incorporation. This ownership limitation may be increased or decreased to any other percentage designated by such holder of Class B common stock upon 61 days’ notice to the Company. Voting rights Except as otherwise expressly provided in the Company’s amended and restated certificate of incorporation or as required by applicable law, on any matter that is submitted to a vote by the Company’s stockholders, holders of the Company’s common stock are entitled to one vote per share of common stock, and holders of the Company’s Class B common stock are not entitled to any votes per share of Class B common stock, including for the election of directors. September 2021 Private Placement of Common Stock In September 2021, the Company entered into agreements to sell 2,678,600 shares of its common stock at a price of $ 28.00 per share through a private investment in public equity financing (or "Private Placement"). Proceeds from the Private Placement, net of underwriting discounts and commissions and other offering costs, were $ 71.0 million. In connection with the Private Placement, the Company also issued registration rights to the investors. The Company filed a registration statement on Form S-1 (File No. 333-260440) with the SEC registering for resale the shares of common stock issued in the Private Placement. November 2022 Underwritten Offering On November 8, 2022, the Company completed a follow-on offering under its shelf registration statement on Form S-3 (File No. 333-262528) and a related prospectus supplement pursuant to which the Company issued an aggregate of 9,745,128 shares of its common stock to at a public offering price of $ 6.67 per share. The Company received aggregate net proceeds of $ 61.7 million fro m the offering after deducting underwriting discounts and commissions and other offering expenses. Common stock warrants The Company issued the warrants described below in 2016 in connection with certain advisory services. The warrants became exercisable upon our IPO for a period of 365 and 450 days . Upon adoption of ASU No. 2018-07 on October 1, 2020, the measurement date of the warrants became fixed in accordance with the guidance, and such fair value was nominal since the warrants were deeply out-of-the-money. In December 2021, a total of 566,586 warrants with an exercise period of 365 days after our IPO expired unexercised. The remaining 151,088 warrants with an exercise period of 450 days after the Company's IPO expired unexercised in March 2022. Accordingly, there are no remaining common stock warrants outstanding and exercisable at December 31, 2022. 2020 Equity Incentive Plan On October 29, 2020, the Company’s board of directors approved the adoption of the BioAtla, Inc. 2020 Equity Incentive Plan (the “2020 Plan”) and approved certain amendments to the 2020 Plan in December 2020. The Company’s stockholders approved the 2020 Plan, as amended, in December 2020. Under the 2020 Plan, the Company may grant awards of common stock to the Company’s employees, consultants and non-employee directors pursuant to option awards, stock appreciation rights awards, restricted stock awards, restricted stock unit awards, performance stock awards, performance stock unit awards and other stock-based awards. As of December 31, 2022 and 2021 , the total number of common shares authorized for issuance under the 2020 Plan was 7,658,509 and 6,226,540 , respectively. On January 1st of each year, commencing with the first January 1st following the effective date of the 2020 Plan, the shares authorized for issuance under the 2020 Plan shall be increased by a number of shares equal to the lesser of 4 % of the total number of shares outstanding on the immediately preceding December 31st and such lesser number of shares determined by the Company’s board of directors. The maximum term of the options granted under the 2020 Plan is no more than ten years . Awards under the 2020 Plan generally vest at 25 % one year from the vesting commencement date and ratably each month thereafter for a period of 36 months, subject to continuous service. Stock-based compensation expense recognized for all equity awards under the 2020 Plan has been reported in the consolidated statements of operations and comprehensive loss as follows (in thousands): Years ended December 31, 2022 2021 Research and development $ 5,419 $ 4,688 General and administrative 9,144 20,429 Total $ 14,563 $ 25,117 Restricted stock units The following table summarizes RSU activity under the 2020 Plan for the years ended December 31, 2022 and 2021: Number of Weighted - Outstanding at December 31, 2020 1,920,037 $ — Granted — $ 18 Vested ( 944,991 ) $ — Outstanding at December 31, 2021 975,046 $ 18.00 Granted — $ — Vested ( 446,260 ) $ 18.00 Forfeited ( 18,747 ) Outstanding at December 31, 2022 510,039 $ 18.00 As of December 31, 2022 , total unrecognized stock-based compensation expense for RSUs was $ 9.2 million, which is expected to be recognized over a remaining weighted-average period of approximately 1.3 years. Stock options The following table summarizes stock option activity under the 2020 Plan for the year ended December 31, 2022 and 2021 (in thousands, except share and per option data and years): Number of Weighted - Weighted - Aggregate Balance at December 31, 2020 615,106 $ 18.00 9.95 $ 9,848 Granted 479,543 $ 37.86 Exercised ( 7,747 ) $ 18.00 Balance at December 31, 2021 1,086,902 $ 26.76 9.22 $ 991,495 Granted 1,718,200 $ 6.35 Exercised — $ — — $ — Forfeited ( 50,387 ) $ 21.64 Expired ( 17,797 ) $ 40.00 Balance at December 31, 2022 2,736,918 $ 13.82 8.82 $ 3,636,148 Vested and expected to vest at December 31, 2022 2,736,918 $ 13.82 8.82 $ 3,636,148 Exercisable at December 31, 2022 496,074 $ 25.95 8.10 $ — As of December 31, 2022 , total unrecognized stock-based compensation cost for unvested common stock options was $ 14.9 million, which is expected to be recognized over a remaining weighted-average period of approximately 2.9 years. The weighted- average grant date fair value of stock options granted during the years ended December 31, 2022 and 2021 was $ 4.06 per share and $ 24.61 per share, respectively. The total fair value of options vested during the years ended December 31, 2022 and 2021 was $ 6.9 million and $ 1.9 million, respectively. Upon option exercise, the Company issues new shares of its common stock. The assumptions used in the Black-Scholes option pricing model to determine the fair value of stock option grants were as follows: Years ended December 31, 2022 2021 Expected volatility 74.9 % 74.7 % Risk-free interest rate 2.14 % 1.06 % Expected dividend yield 0.0 % 0.0 % Expected term 6.04 years 5.98 years Expected volatility. As the Company’s common stock does not have a significant trading history, the expected volatility assumption is based on volatilities of a peer group of similar companies whose share prices are publicly available. The peer group was developed based on companies in the biotechnology industry. Risk-free interest rate. The Company bases the risk-free interest rate assumption on the U.S. Treasury’s rates for U.S. Treasury zero-coupon bonds with maturities similar to those of the expected term of the award being valued. Expected dividend yield. The Company bases the expected dividend yield assumption on the fact that it has never paid cash dividends and has no present plans to pay cash dividends. Expected term. For employees, the expected term represents the period of time that options are expected to be outstanding. Because the Company has minimal historical exercise behavior, it determines the expected life assumption using the simplified method, which is an average of the contractual term of the option and its vesting period. For nonemployees, the expected term is generally the contractual term of the option. Employee Stock Purchase Plan In December 2020, the Company’s board of directors and stockholders approved the BioAtla, Inc. Employee Stock Purchase Plan (the “ESPP”). The ESPP permits participants to purchase common stock through payroll deductions of up to 15 % of their eligible compensation. As of December 31, 2022 and 2021 , a total of 1,229,148 and 833,993 shares, respectively, of common stock were authorized for issuance under the ESPP. The number of shares of common stock authorized for issuance will automatically increase on January 1 of each calendar year, from January 1, 2021 through January 1, 2030 by the least of (i) 1.0 % of the total number of common shares of our common stock outstanding on December 31 of the preceding calendar year (calculated on a fully diluted basis), (ii) 929,658 common shares or (iii) a number determined by the Company’s board of directors that is less than (i) and (ii) . The ESPP plan was amended in September 2021 to change the offering periods to end on May 15th and November 15th of each year beginning January 1, 2022. In February 2021, employees began to enroll in the ESPP, and the Company’s first offering period commenced. During the years ended December 31, 2022 and 2021 , the Company issued 147,564 and 11,182 shares of common stock under the ESPP, respectively. As of December 31, 2022 , 1,070,402 shares of common stock remained available for issuance under the ESPP. Stock-based compensation expense related to the ESPP for the twelve months ended December 31, 2022 and 2021 was $ 0.2 million and $ 0.1 million, respectively. Common stock reserved for future issuance Common stock reserved for future issuance are as follows in common equivalent shares: December 31, 2022 2021 Warrants for the purchase of common stock — 151,088 Common stock options and restricted stock units issued and outstanding 3,246,957 2,061,948 Awards available for future issuance under the 2020 Plan 3,012,554 3,211,854 Awards available for future issuance under the ESPP 1,070,402 822,811 Total common stock reserved for future issuance 7,329,913 6,247,701

Collaboration, license and opti

Collaboration, license and option agreements	12 Months Ended
	Dec. 31, 2022
Collaboration License And Option Agreements [Abstract]
Collaboration, license and option agreements	. Collaboration, license and option agreements Global Co-Development and Collaboration Agreement with BeiGene In April 2019, the Company entered into a Global Co-Development and Collaboration agreement (the “BeiGene Collaboration”) with BeiGene, Ltd. and BeiGene Switzerland GmbH (collectively “BeiGene”), for the development, manufacturing and commercialization of the Company’s investigational CAB CTLA-4 antibody (BA3071). The BeiGene Collaboration was amended several times between 2019 and 2021 and the Company received a total of $ 25.0 million in non-refundable payments from BeiGene during that time. In November 2021, the BeiGene Collaboration was terminated, subject to survival of certain provisions, and BeiGene handed back rights to know-how and materials received under the amended BeiGene Collaboration. As a result, the Company is responsible for the global development and commercialization of BA3071. As consideration for this amendment, the Company agreed to pay BeiGene mid-single digit royalties on sales worldwide and on a limited basis will share in any upfront and milestone payments received through a sublicense of BA3071. The Company reclassified its then remaining $ 19.8 million of deferred revenue as a long-term liability which is expected to settle as licensing payments are made to BeiGene in accordance with the resulting amendment. In the event the license is terminated, the liability will be extinguished with no further payment to BeiGene. The Company did no t recognize any revenue related to the collaboration agreement with BeiGene for the years ended December 31, 2022 and 2021. The Company had a $ 19.8 million Liability to Licensor as of December 31, 2022 and 2021. Collaboration and Supply Agreement with Bristol-Myers Squib On January 5, 2022, BioAtla and Bristol-Myers Squibb Company (“BMS”) entered into a clinical trial collaboration and supply agreement (the “BMS Agreement”). Under the terms of the BMS Agreement, BioAtla and BMS will collaborate on clinical trials of separate combination therapies using two of BioAtla’s Conditionally Active Biologic Antibody Drug Conjugates, BA3011 and BA3021, each in combination with Opdivo® (nivolumab), BMS’ proprietary anti-PD-1 monoclonal antibody product. The Company will serve as the study sponsor of the scheduled studies and will be responsible for costs associated with the trial execution. BMS will provide Opdivo® clinical drug supply at no cost for the combination study trials. After the completion of the combination therapy trials, the Company is obligated to provide BMS with a final report of the data resulting from the trial. The BMS Agreement was amended in October 2022 to include additional territories for our BA3011 and BA3021 combination study trials. There was no impact to the Company's financial results for the years ended December 31, 2022 or 2021 as a result of this agreement. Exclusive License Agreement with Exuma Biotech Corp Under an Exclusive License Agreement entered into in May 2016, the Company granted EXUMA and its affiliates an exclusive, worldwide, sublicensable license under certain patents and know-how controlled by the Company to develop, manufacture and commercialize Adoptive Cellular Therapy (“ACT”) preparations and treatments for cancer. EXUMA’s rights under the agreement exclude the right to grant sublicenses to third parties to discover, develop or manufacture any CAB ACT or any component of the Company’s CAB ACT technology, except as used in or incorporated into EXUMA’s ACTs for cancer. The license to EXUMA is royalty bearing. EXUMA granted the Company an exclusive, worldwide, royalty free, fully paid-up, sublicensable license under certain patents and know-how controlled by EXUMA and EXUMA’s interest in technology jointly developed under the agreement to develop, manufacture and commercialize non-ACT CAB products for any indication. EXUMA is obligated to pay the Company during the royalty term, on a product-by-product basis and country-by-country basis, mid-single digit royalties based on annual net sales of certain EXUMA ACT products, subject to certain adjustments. The term during which EXUMA is obligated to pay royalties under the agreement with respect to any particular product in any particular country, will begin on the first commercial sale of such product in such country and will end on the date of expiration of the last-to-expire of certain product-related patent rights in such country. All royalties to be paid under the agreement are subject to certain adjustments. Future royalties will be recognized when earned. Service Contracts Prior to developing its own programs, the Company entered into various fixed price research services contracts. In connection with these service contracts, the Company may receive future milestone payments if certain clinical, regulatory and commercialization milestones are achieved. The Company is also eligible to receive royalties based on certain product sales. The Company recognized revenue of $ 0.3 million for the year ended December 31, 2021, related to the achievement of a clinical milestone on a fixed price service contract.

Related party transactions

Related party transactions	12 Months Ended
	Dec. 31, 2022
Related Party Transactions [Abstract]
Related party transactions	9. Related party transactions Dr. Jay Short and Carolyn Anderson Short On March 23, 2021, the Company entered into a transition agreement with Ms. Anderson Short, our Co-founder and Executive Vice President and Chief of Intellectual Property and Strategy at that time. Pursuant to this transition agreement, Ms. Anderson Short continued in her role with the same base salary and employee benefits until her employment with the Company was terminated on May 31, 2021. Upon her separation from the Company and subject to her execution of a release of claims, Ms. Anderson Short received the following severance benefits as set forth in the transition agreement, which satisfied existing severance obligations owing to her under a legacy pre-IPO severance agreement she had entered into with the Company on July 1, 2018: (i) a lump sum payment equal to 18 months of Ms. Anderson Short’s then-current base salary, (ii) a payment at her targeted bonus rate for 2021, pro-rated to the date of her termination of employment, and (iii) full accelerated vesting of her equity awards including 7,747 stock options and 138,461 restricted stock units. The modification of these equity awards resulted in an incremental fair value of $ 7.0 million which was recognized on a straight-line basis over the transition service period which ended on the separation date. For the year ended December 31, 2021, the Company recognized $ 1.0 million related to the lump sum salary payment and target bonus. The Company also recognized non-cash stock-based compensation charges of $ 9.4 million related to the modified equity awards for the year ended December 31, 2021. No unrecognized stock-based compensation related to the transition agreement was recognized for the year ended December 31, 2022. Inversagen, LLC On March 15, 2019, the Company entered into an Exclusive License Agreement with Inversagen (the “Inversagen License”). Under the terms of the agreement, Inversagen acquired the rights to CAB-antibodies for the field of diseases associated with aging, outside of cancer, and an immuno-oncology antibody. The Company may perform development services under the agreement and will be reimbursed by Inversagen for its costs. Commencing on the first commercial sale of the CAB-antibodies and immuno-oncology antibody subject to the Inversagen License, Inversagen will pay the Company milestone payments and royalties, which represent a variable interest held by the Company. On July 7, 2020, the Company and Inversagen entered into the First Amendment to Exclusive License Agreement (“Amended Inversagen License”), which grants the Company an option for a period of 10 years to acquire the immuno-oncology antibody in return for royalty payments in the low-single digits during the applicable royalty term. No payments have been made to date. Inversagen has only nominal assets and liabilities and is a VIE as the entity lacks sufficient equity to finance its activities without additional subordinated financial support. The Company does not consolidate Inversagen as it is not the primary beneficiary; Inversagen License and the Amended Inversagen License did not and do not provide the Company with any decision-making power over the activities that are most significant to the entity’s economic success, such as the direction of its development efforts or the search for or terms of any future financing arrangements. The Company has no equity interest in Inversagen, and no exposure to its losses. The Company has not provided any services to Inversagen, has not provided any support to Inversagen and has no obligation to do so, and Inversagen’s creditors have no recourse to the general credit of the Company. The Company does no t have any assets or liabilities associated with its variable interest in Inversagen at December 31, 2022 and 2021. Inversagen is a related party of the Company. Dr. Jay Short and his spouse, Carolyn Anderson Short, serve as managers of Inversagen. BioAtla Holdings, LLC Effective January 1, 2020, the Company entered into an Exclusive License Agreement (the “BioAtla Holdings License”) with BioAtla Holdings, LLC. Under the terms of the agreement, BioAtla Holdings acquired the rights to CAB antibodies for certain targets in the field of Adoptive Cell Therapy (CAR-T format) in exchange for potential royalty payments on future net sales. On July 7, 2020, the Company and BioAtla Holdings entered into the First Amendment to Exclusive License Agreement (the “Amended BioAtla Holdings License”), which grants the Company an option for a period of 10 years to acquire the ACT Preparations and ACT Treatments in return for royalty payments in the low-single digits during the applicable royalty term. The Company has not exercised its option and no payments have been made to date under these agreements. In addition, effective January 1, 2020, the Company entered into a Royalty Sharing Agreement whereby the Company agreed to share with BioAtla Holdings 50 % of the royalties it receives under the Amended and Restated EXUMA License defined and described in Note 12 below. BioAtla Holdings is a variable interest entity as it does not have sufficient equity to finance its activities without additional subordinated financial support. The royalty payments and option to acquire assets represent variable interests held by the Company in BioAtla Holdings. The Company is not the primary beneficiary of BioAtla Holdings, however, as the BioAtla Holdings License and Amended BioAtla Holdings License did not and do not provide the Company with any decision-making power over the activities that are most significant to the entity’s economic success, such as the direction of its development efforts or the search for or terms of any future financing arrangements. The Company has no equity interest in BioAtla Holdings, and no exposure to its losses. BioAtla Holdings is currently inactive, and the Company has not provided any support to BioAtla Holdings and has no obligation to do so, and BioAtla Holdings’ creditors have no recourse to the general credit of the Company. The Company does no t have any assets or liabilities associated with its variable interests in BioAtla Holdings at December 31, 2022 and 2021. BioAtla Holdings is a related party of the Company. Dr. Jay Short and his spouse, Carolyn Anderson Short, serve as managers of BioAtla Holdings. Himalaya Therapeutics SEZC Exclusive Rights Agreement On January 1, 2020, the Company entered into an Amended and Restated Exclusive Rights Agreement (the “Amended Rights Agreement”) with Himalaya Therapeutics SEZC. Under the terms of the Amended Rights Agreement, Himalaya Therapeutics SEZC acquired the rights to 10 CAB-antibodies for the territory of China, Macao, Hong Kong and Taiwan, global rights to a CAB-HER2-bispecific-antibody and global co-development rights with the Company to an IL-22 non-CAB-antibody. Payments to the Company may include upfront payments, milestone payments and double digit royalties, which represent a variable interest held by the Company, but no payments have been made to the Company to date. Himalaya Therapeutics SEZC is a variable interest entity as it does not have sufficient equity to finance its activities without additional subordinated financial support. The Company is not obligated to provide financial support to Himalaya Therapeutics SEZC. The Company is not the primary beneficiary of Himalaya Therapeutics SEZC, however, as the Amended Rights Agreement does not provide BioAtla, Inc. with the power to direct activities of a VIE that most significantly impact the VIE’s economic performance, such as decision-making power over the direction of its development efforts or the search for or terms of any future financing arrangements. The Company does no t have any assets or liabilities recorded at December 31, 2022 associated with its variable interest in Himalaya Therapeutics SEZC, and has no exposure to Himalaya Therapeutics SEZC losses. Himalaya Therapeutics SEZC is a related party as Dr. Jay Short and his spouse, Carolyn Anderson Short, serve as directors, and Carolyn Anderson Short also serves as an officer of such entity. Clinical Trial Services Agreement In April 2022, the Company entered into a Clinical Trial Agreement with Himalaya Therapeutics SEZC. Under the agreement, Himalaya Therapeutics SEZC agreed to provide services related to the initiation of clinical trials for BA3011 in the People’s Republic of China. For the first year following effectiveness of the agreement, the Company has agreed to pay Himalaya Therapeutics SEZC for the full-time use of two of its personnel. Payments are due and payable by BioAtla to Himalaya Therapeutics SEZC on a quarterly calendar basis and are non-refundable. For the twelve months ended December 31, 2022, the Company recognized $ 0.4 million in research and development expense related to the Clinical Trial Agreement. The Company did not have any amounts due from or due to Himalaya Therapeutics SEZC as of December 31, 2022 . Himalaya Parent LLC Dr. Jay Short and his spouse, Carolyn Anderson Short, serve as managers of Himalaya Parent LLC. The Company does not have a variable interest in Himalaya Parent LLC. Private Placement of Common Stock As part of the 2021 Private Placement, the Company issued 625,000 shares of common stock for total net proceeds of $ 17.5 million to certain stockholders considered to be related parties. November 2022 Underwritten Offering As part of the 2022 underwritten offering, the Company issued 2,998,500 shares of common stock for total net proceeds of $ 19.1 million to certain stockholders considered to be related parties.

401(k) plan

401(k) plan	12 Months Ended
	Dec. 31, 2022
Retirement Benefits [Abstract]
401(k) plan	10. 401(k) plan The Company maintains a defined contribution 401(k) plan available to eligible employees. Employee contributions are voluntary and are determined on an individual basis, limited to the maximum amount allowable under federal tax regulations. The Company, at its discretion, may make certain matching contributions to the 401(k) plan. To date, the Company has no t made any matching contributions.

Income taxes

Income taxes	12 Months Ended
	Dec. 31, 2022
Income Tax Disclosure [Abstract]
Income taxes	11. Income taxes A reconciliation of income tax expense computed at the U.S. federal statutory income tax rate to the Company’s income tax expense is as follows (in thousands): Years Ended December 31, 2022 2021 Tax computed at the federal statutory rate $ ( 22,361 ) $ ( 20,034 ) State income taxes, net of federal tax benefit ( 6 ) — Deferred impact of conversion to C Corporation — ( 2,131 ) Nondeductible executive compensation 685 4,145 Stock-based compensation 1,132 ( 1,021 ) Research and development and orphan drug credits ( 3,692 ) ( 3,091 ) Uncertain tax positions 910 757 Other, net ( 23 ) 793 Valuation allowance 23,355 20,582 Income tax expense $ — $ — The Company’s net deferred tax assets (liabilities) are as follows (in thousands): Years Ended December 31, 2022 2021 Deferred tax assets: Net operating loss carryforwards $ 17,430 $ 21,935 Liability to licensor 4,159 4,159 Goodwill 3,193 3,449 Lease liability 836 1,128 Accrued compensation 659 485 Research credit carryforwards 5,760 2,945 Section 174 cost capitalization 14,523 — Section 59(e) cost capitalization 9,450 — Stock-based compensation 1,628 697 Other 3 2 Gross deferred tax assets 57,641 34,800 Less: valuation allowance ( 56,706 ) ( 33,351 ) Total deferred tax assets 935 1,449 Deferred tax liabilities: Fixed assets ( 426 ) ( 756 ) Operating lease right-of-use asset ( 509 ) ( 693 ) Total deferred tax liabilities ( 935 ) ( 1,449 ) Net deferred tax assets $ — $ — A valuation allowance of approximately $ 56.7 million as of December 31, 2022 has been established to offset the deferred tax assets as the Company has determined that it is not more likely than not that these assets will be realized. The valuation allowance increased by approximately $ 23.4 million during 2022. At December 31, 2022 , the Company had federal and state net operating loss carryforwards of approximately $ 83.0 million and $ 0.2 million, respectively. The federal and state net operating losses can be carried forward indefinitely, subject to an 80% limitation against taxable income. At December 31, 2022 , the Company had federal and California research and development credit carryforwards of approximately $ 3.7 million and $ 2.0 million, respectively. The federal credit carryforwards will begin to expire in 2040 , unless previously utilized. The California credits will carry forward indefinitely. At December 31, 2022 , the Company also had federal orphan drug credit carryforwards of approximately $ 2.3 million. The orphan drug credit carryforwards will begin to expire in 2041 , unless previously utilized. Pursuant to Internal Revenue Code (“IRC”) Sections 382 and 383, annual use of the Company’s net operating loss carryforwards may be limited in the event a cumulative change in ownership of more than 50 % occurs within a three-year period. The Company has not completed an ownership change analysis pursuant to IRC Section 382. If ownership changes within the meaning of IRC Section 382 are identified as having occurred, the amount of remaining tax attribute carryforwards available to offset future taxable income and income tax expense in future years may be significantly restricted or eliminated. Further, the Company’s deferred tax assets associated with such tax attributes could be significantly reduced upon realization of an ownership change within the meaning of IRC Section 382. Pursuant to the Paycheck Protection Program (the “PPP”) of the CARES Act, the Company received a PPP loan in the amount of $ 0.7 million. In 2021, the Company received forgiveness of the PPP loan. The loan forgiveness income is not considered taxable for Federal or state income tax purposes. In accordance with the Consolidated Appropriations Act, 2021 (CAA) enacted on December 27, 2020, certain qualified expenses used with the funds of the PPP Loan are fully deductible for Federal income tax purposes; however, California does not conform to this aspect of the CAA. Under the FASB's accounting guidance related to income tax positions, among other things, the impact of an uncertain income tax position on the income tax return must be recognized at the largest amount that is more-likely-than-not to be sustained upon audit by the relevant taxing authority. An uncertain income tax position will not be recognized if it has less than a 50% likelihood of being sustained. Additionally, the guidance provides guidance on derecognition, classification, interest and penalties, accounting in interim period, disclosure and transition. The Company regularly evaluates the likelihood of recognizing the benefit for income tax positions taken in various federal and state filings by considering all relevant facts, circumstances, and information available. A reconciliation of the beginning and ending unrecognized tax benefit amount is as follows (in thousands): Years Ended December 31, 2022 2021 Unrecognized tax benefits - beginning $ 1,011 $ 210 Gross increases - tax positions in prior period 11 0 Gross increase – current-period tax positions 946 801 Unrecognized tax benefits - ending $ 1,968 $ 1,011 As of December 31, 2022 , the Company had gross unrecognized tax benefits of approximately $ 2.0 million, none of which would affect the Company’s effective tax rate due to the existence of the valuation allowance. The Company’s policy is to recognize interest and penalties related to income tax matters in income tax expense. The Company had no accrual for interest or penalties on the Company’s consolidated balance sheet and has not recognized interest or penalties in the consolidated statements of net and comprehensive income for the year ended December 31, 2022. The Company does not anticipate a significant change to its liability for unrecognized tax benefits within the next twelve months. The Company is subject to taxation in the United States and various state jurisdictions. The Company is subject to examination by tax authorities in those jurisdictions since 2019 and 2018, respectively, and forward. However, to the extent allowed by law, the taxing authorities may have the right to examine periods where NOLs and research and development credits were generated and carried forward, and make adjustments to the amount of the NOL and research credits carryforward amount. The Company is not currently under examination by any jurisdiction.

Subsequent events

Subsequent events	12 Months Ended
	Dec. 31, 2022
Subsequent Events [Abstract]
Subsequent events	12. Subsequent events The Company has completed an evaluation of all subsequent events through March 23, 2023 for the financial statements as of and for the year ended December 31, 2022 to ensure these consolidated financial statements include appropriate disclosure of events both recognized in the consolidated financial statements and events which occurred but were not recognized in the consolidated financial statements. Except as described below or elsewhere in these consolidated financial statements, the Company has concluded that no subsequent event has occurred that requires disclosure. In January 2023, BioAtla, Inc. (the “Company”) entered into an open market sale agreement under which the Company may offer and sell, from time to time in its sole discretion, shares of the Company’s common stock, par value $ 0.0001 per share, with aggregate gross sales proceeds of up to $ 100,000,000 through an “at the market” equity offering program under which Jefferies LLC will act as sales agent. No shares have been sold under the agreement to date.

Organization and summary of s_2

Organization and summary of significant accounting policies (Policies)	12 Months Ended
	Dec. 31, 2022
Accounting Policies [Abstract]
Organization	Organization BioAtla, LLC was formed in Delaware in March 2007 and was converted to a Delaware corporation in July 2020 and renamed BioAtla, Inc. (the “Company”). The Company has a proprietary platform for creating biologics, including its conditionally active biologics (“CAB” or “CABs”). CABs have been designed to be active only under certain conditions found in diseased tissue, while remaining inactive in normal tissue. The Company is currently in clinical development of its two lead CAB antibody drug conjugates (“CAB ADC”) targeting AXL and ROR2 receptors, and its CAB immune-oncology antibody targeting CTLA-4.
Basis of Presentation	Basis of Presentation The accompanying consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”). BioAtla, Inc. is a single legal entity with no consolidated variable interest entities ("VIEs") or subsidiaries (see Note 9).
Liquidity and going concern	Liquidity and Going Concern The Company has incurred cumulative operating losses and negative cash flows from operations since its inception and expects to continue to incur significant expenses and operating losses for the foreseeable future as it continues the development of its product candidates. As of December 31, 2022, the Company had an accumulated deficit of $ 292.8 million . The Company plans to continue to fund its losses from operations and capital funding needs through public or private equity or debt financings, or other sources. If the Company is not able to secure adequate additional funding, the Company may be forced to make reductions in spending, extend payment terms with suppliers, liquidate assets where possible, or suspend or curtail planned programs. Any of these actions could materially harm the Company’s business, results of operations and future prospects. Management is required to perform a two-step analysis of the Company’s ability to continue as a going concern. Management must first evaluate whether there are conditions and events that raise substantial doubt about the Company’s ability to continue as a going concern (Step 1). If management concludes that substantial doubt is raised, management is also required to consider whether its plans alleviate that doubt (Step 2). Management’s assessment included the preparation of cash flow forecasts resulting in management’s conclusion that there is not substantial doubt about the Company’s ability to continue as a going concern for 12 months after the date the consolidated financial statements for the year ended December 31, 2022 are issued.
Variable interest entities	Variable Interest Entities The Company consolidates entities in which it has a controlling financial interest. The Company determines whether it has a controlling financial interest in an entity by first evaluating whether the entity is a voting interest entity or a variable interest entity (“VIE”). VIEs are entities in which (i) the total equity investment at risk is sufficient to enable the entity to finance its activities independently, (ii) the equity holders have the power to direct the activities of the entity that most significantly impact its economic performance, the obligation to absorb the losses of the entity and the right to receive the residual returns of the entity and (iii) the legal entity is structured with substantive voting rights. A VIE is an entity that lacks one or more of the characteristics of a voting interest entity. The Company has a controlling financial interest in a VIE when the Company has a variable interest or interests that provide it with (i) the power to direct the activities of the VIE that most significantly impact the VIE’s economic performance and (ii) the obligation to absorb losses of the VIE or the right to receive benefits from the VIE that could potentially be significant to the VIE. The Company evaluates its relationships with its VIEs on an ongoing basis to determine whether or not it has a controlling financial interest (see Note 9).
Use of estimates	Use of Estimates The Company’s consolidated financial statements are prepared in accordance with U.S. generally accepted accounting principles (“GAAP”). The preparation of the Company’s consolidated financial statements requires it to make estimates and assumptions that impact the reported amounts of assets, liabilities, revenues and expenses and the disclosure of contingent assets and liabilities in the Company’s consolidated financial statements and accompanying notes. The most significant estimates in the Company’s consolidated financial statements relate to revenue recognition, accruals for research and development costs, equity-based compensation and fair value measurements. These estimates and assumptions are based on current facts, historical experience and various other factors believed to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities and the recording of revenue and expenses that are not readily apparent from other sources. Actual results may differ materially and adversely from these estimates. To the extent there are material differences between the estimates and actual results, the Company’s future results of operations will be affected.
Segment reporting	Segment Reporting Operating segments are identified as components of an enterprise about which separate discrete financial information is available for evaluation by the chief operating decision-maker in making decisions regarding resource allocation and assessing performance. The Company views its operations and manages its business in one operating segment.
Cash and cash equivalents	Cash and Cash Equivalents The Company considers all highly liquid investments with original maturities of three months or less when purchased to be cash equivalents.
Concentration of risk	Concentrations of Risk Financial instruments that potentially subject the Company to a significant 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. The Company has not experienced any losses in such accounts and management believes that the Company is not exposed to significant credit risk due to the financial position of the depository institutions in which those deposits are held.
Property and equipment	Property and Equipment Property and equipment are stated at cost and depreciated on a straight-line basis over the estimated useful life of the related assets. Leasehold improvements are stated at cost and amortized on a straight-line basis over the lesser of the remaining term of the related lease or the estimated useful life of the leasehold improvements. Repairs and maintenance costs are charged to expense as incurred and expenditures that materially extend the useful lives of assets are capitalized.
Impairment of long-lived assets	Impairment of Long-Lived Assets The Company reviews long-lived assets, such as property and equipment, for impairment whenever events or changes in circumstances indicate the carrying amount of an asset may not be recoverable. Recoverability of assets to be held and used is measured by a comparison of the carrying amount of an asset to the future undiscounted net cash flows expected to be generated by the asset. 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 the fair value of the assets. Fair value would be assessed using discounted cash flows or other appropriate measures of fair value. The Company has no t recognized any impairment losses for the years ended December 31, 2022 and 2021 .
Leases	Leases The Company determines if an arrangement is a lease at inception. An arrangement is or contains a lease if it conveys the right to control the use of an identified asset for a period of time in exchange for consideration. If a lease is identified, classification is determined at lease commencement. Operating lease liabilities are recognized at the present value of the future lease payments at the lease commencement date. The Company’s leases do not provide an implicit interest rate and therefore the Company estimates its incremental borrowing rate to discount lease payments. The incremental borrowing rate reflects the interest rate that the Company would have to pay to borrow on a collateralized basis an amount equal to the lease payments in a similar economic environment over a similar term. Operating lease right-of-use (“ROU”) assets are based on the corresponding lease liability adjusted for any lease payments made at or before commencement, initial direct costs, and lease incentives. Renewals or early terminations are not accounted for unless the Company is reasonably certain to exercise these options. Operating lease expense is recognized and the ROU asset is amortized on a straight-line basis over the lease term. Variable lease costs are not included in the calculation of the ROU asset and the related lease liability and are recognized as incurred. The Company has a single lease agreement with lease and non-lease components, which are accounted for as a single lease component. Lease payments for short-term leases, defined as leases with a term of twelve months or less, are expensed on a straight-line basis over the lease term. The Company does not currently have any short-term leases. Operating leases are included in operating lease right-of-use assets, operating lease liabilities, and operating lease liabilities, non-current on the Company’s consolidated balance sheets. The Company does not have any finance leases.
Revenue recognition	Revenue Recognition The Company recognizes revenue in a manner that depicts the transfer of control of a product or a service to a customer and reflects the amount of the consideration the Company is entitled to receive in exchange for such product or service. In doing so, the Company follows a five-step approach: (i) identify the contract 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, and (v) recognize revenue when (or as) the customer obtains control of the product or service. The Company considers the terms of a contract and all relevant facts and circumstances when applying the revenue recognition standard. A customer is a party that has entered into a contract with the Company, where the purpose of the contract is to obtain a product or a service that is an output of the Company’s ordinary activities in exchange for consideration. To be considered a contract, (i) the contract must be approved (in writing, orally, or in accordance with other customary business practices), (ii) each party’s rights regarding the product or the service to be transferred can be identified, (iii) the payment terms for the product or the service to be transferred can be identified, (iv) the contract must have commercial substance (that is, the risk, timing or amount of future cash flows is expected to change as a result of the contract), and (v) it is probable that the Company will collect substantially all of the consideration to which it is entitled to receive in exchange for the transfer of the product or the service. A performance obligation is defined as a promise to transfer a product or a service to a customer. The Company identifies each promise to transfer a product or a service (or a bundle of products or services, or a series of products and services that are substantially the same and have the same pattern of transfer) that is distinct. A product or a service is distinct if both (i) the customer can benefit from the product or the service either on its own or together with other resources that are readily available to the customer and (ii) the Company’s promise to transfer the product or the service to the customer is separately identifiable from other promises in the contract. Each distinct promise to transfer a product or a service is a unit of accounting for revenue recognition. If a promise to transfer a product or a service is not separately identifiable from other promises in the contract, such promises should be combined into a single performance obligation. The transaction price is the amount of consideration the Company is entitled to receive in exchange for the transfer of control of a product or a service to a customer. To determine the transaction price, the Company considers the existence of any significant financing component, the effects of any variable elements, noncash consideration and consideration payable to the customer. If a significant financing component exists, the transaction price is adjusted for the time value of money. If an element of variability exists, the Company must estimate the consideration it expects to receive and uses that amount as the basis for recognizing revenue as the product or the service is transferred to the customer. There are two methods for determining the amount of variable consideration: (i) the expected value method, which is the sum of probability-weighted amounts in a range of possible consideration amounts, and (ii) the mostly likely amount method, which identifies the single most likely amount in a range of possible consideration amounts. If a contract has multiple performance obligations, the Company allocates the transaction price to each distinct performance obligation in an amount that reflects the consideration the Company is entitled to receive in exchange for satisfying each distinct performance obligation. For each distinct performance obligation, revenue is recognized when the Company transfers control of the product or the service applicable to such performance obligation. In those instances where the Company first receives consideration in advance of satisfying its performance obligation, the Company classifies such consideration as deferred revenue until (or as) the Company satisfies such performance obligation. In those instances where the Company first satisfies its performance obligation prior to its receipt of consideration, the consideration is recorded as accounts receivable. The Company expenses incremental costs of obtaining and fulfilling a contract as incurred if the expected amortization period of the asset that would be recognized is one year or less, or if the amount of the asset is immaterial. Otherwise, such costs are capitalized as contract assets if they are incremental to the contract and amortized to expense proportionate to revenue recognition of the underlying contract.
Research and development expenses	Research and Development Expenses The Company’s activities have largely consisted of research and development efforts related to developing our CAB programs. Research and development expenses consist of expenses incurred in performing research and development activities including salaries and benefits, facilities and other overhead expenses, clinical trials, contract services and other outside expenses. Research and development expenses are charged to expense as incurred. Payments for these activities are based on the terms of the individual agreements, which may differ from the pattern of costs incurred, and are reflected in the accompanying consolidated balance sheets as prepaid or accrued expenses. When evaluating the adequacy of the accrued expenses, the Company analyzes progress of the services, including the phase or completion of events, invoices received and contracted costs. Significant judgments and estimates may be made in determining the accrued balances at the end of any reporting period. Actual results could differ from the Company’s estimates. As of December 31, 2022, the Company has accrued $ 5.5 million related to clinical trial costs. The Company has entered into contracts related to its clinical trials with clinical research organizations. The Company reviews and accrues clinical trial costs based on work performed, which relies on estimates of total trial management costs, sites activated, patients enrolled, and number of patient visits. The Company follows this method since reasonably dependable estimates of the costs applicable to clinical trials can be made. Accrued clinical trial costs are subject to revisions as the trials progress. Revisions are charged to expense in the period in which the facts that give rise to the revision become known. Historically, revisions have not resulted in material changes to research and development expense; however, a modification in the protocol of a clinical trial or cancellation of a trial could result in a change to the Company's results of operations.
Patent costs	Patent Costs Costs related to filing and pursuing patent applications are recorded as general and administrative expenses and expensed as incurred since recoverability of such expenditures is uncertain.
Stock-based compensation	Stock-Based Compensation Stock-based compensation expense represents the grant date fair value of equity awards, consisting of stock options, restricted stock units (“RSUs”) and employee stock purchase plan rights, over the requisite service period of the awards (usually the vesting period) on a straight-line basis. The Company estimates the fair value of stock option grants and employee stock purchase plan rights using the Black-Scholes option pricing model. Prior to the Company’s IPO, the fair value of RSUs was based on the estimated fair value of the underlying common stock on the date of grant and, subsequent to the Company’s IPO, the fair value is based on the closing sales price of the Company’s common stock on the date of grant. Equity award forfeitures are recognized as they occur.
Income taxes	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 based on the differences between the financial statements and tax basis of assets and liabilities using enacted tax rates in effect for the year in which the differences are expected to reverse. The effect of a change in tax rates on deferred tax assets and liabilities is recognized as income in the period that includes the enactment date. The Company recognizes net deferred tax assets to the extent that the Company believes these assets are more likely than not to be realized. In making such a determination, management considers all available positive and negative evidence, including future reversals of existing taxable temporary differences, projected future taxable income, exclusive of reversing temporary difference, tax-planning strategies, and the results of recent operations. If management determines that the Company would be able to realize its deferred tax assets in the future in excess of their net recorded amount, management would make an adjustment to the deferred tax asset valuation allowance, which would reduce the provision for income taxes. The Company records uncertain tax positions on the basis of a two-step process whereby (1) management determines whether it is more likely than not that the tax positions will be sustained on the basis of the technical merits of the position and (2) for those tax positions that meet the more-likely-than-not recognition threshold, management recognizes the largest amount of tax benefit that is more than 50 % likely to be realized upon ultimate settlement with the related tax authority. The Company recognizes interest and penalties related to unrecognized tax benefits within income tax expense. Any accrued interest and penalties are included within the related tax liability.
Comprehensive loss	Comprehensive Loss Comprehensive loss is defined as a change in equity during a period from transactions and other events and circumstances from non-owner sources. There have been no items qualifying as other comprehensive loss and, therefore, for all periods presented, the Company’s comprehensive loss was the same as its reported net loss.
Net loss per unit/share	Net Loss Per Share Basic net loss per common share is computed by dividing the net loss by the weighted-average number of common shares outstanding for the period, without consideration for potentially dilutive securities. Diluted net loss per share is computed by dividing the net loss by the weighted-average number of common shares and dilutive common stock equivalents outstanding for the period determined using the treasury-stock method. Dilutive common stock equivalents are comprised of RSUs, common stock options outstanding under the Company’s stock option plan, and contingently issuable shares under the Company's ESPP plan. Potentially dilutive securities not included in the calculation of diluted net loss per share because to do so would be anti-dilutive are as follows (in common stock equivalents): December 31, 2022 2021 Common stock warrants — 151,088 Common stock options 2,736,918 1,086,902 Restricted stock units 510,039 975,046 ESPP Shares 13,370 — Total 3,260,327 2,213,036
Recent accounting pronouncements	Recent Accounting Pronouncements There were no recently issued or effective FASB Accounting Standards Updates (ASUs) that had, or are expected to have, a material effect on the Company's results of operations, financial condition, or liquidity.

Organization and summary of s_3

Organization and summary of significant accounting policies (Tables)	12 Months Ended
	Dec. 31, 2022
Accounting Policies [Abstract]
Schedule of Anti-dilutive Securities Excluded from Calculation of Diluted Net Loss Per Share	Potentially dilutive securities not included in the calculation of diluted net loss per share because to do so would be anti-dilutive are as follows (in common stock equivalents): December 31, 2022 2021 Common stock warrants — 151,088 Common stock options 2,736,918 1,086,902 Restricted stock units 510,039 975,046 ESPP Shares 13,370 — Total 3,260,327 2,213,036

Balance sheet details (Tables)

Balance sheet details (Tables)	12 Months Ended
	Dec. 31, 2022
Balance Sheet Related Disclosures [Abstract]
Schedule of Prepaid Expenses Other Current Assets	Prepaid expenses and other current assets consist of the following (in thousands): December 31, 2022 2021 Prepaid research and development $ 4,385 $ 1,811 Other prepaid expenses and current assets 539 502 Total $ 4,924 $ 2,313
Schedule of Property and Equipment	Property and equipment consist of the following (in thousands): December 31, Useful life (years) 2022 2021 Furniture, fixtures and office equipment 3 - 7 $ 2,140 $ 2,123 Laboratory equipment 5 2,265 2,123 Leasehold improvements 2 - 3 3,687 3,687 8,092 7,933 Less accumulated depreciation and amortization ( 5,364 ) ( 4,257 ) Total $ 2,728 $ 3,676
Schedule of Accounts Payable and Accrued Expenses	Accounts payable and accrued expenses consist of the following (in thousands): December 31, 2022 2021 Accounts payable $ 4,231 $ 1,179 Accrued compensation 3,451 2,671 Accrued research and development 12,649 13,501 Other accrued expenses 1,279 1,073 Total $ 21,610 $ 18,424

Leases (Tables)

Leases (Tables)	12 Months Ended
	Dec. 31, 2022
Lessee Disclosure [Abstract]
Components of Lease Expense	The components of lease expense included in the Company’s consolidated statements of operations include (in thousands): Years ended December 31, 2022 2021 Operating lease expense $ 1,043 $ 1,043 Variable lease expense 460 512 Total lease expense, net $ 1,503 $ 1,555
Summary of Weighted Average Remaining Lease Term and Weighted Average Discount Rate	The weighted average remaining lease term and weighted average discount rate for operating leases as of December 31, 2022 were as follows: Years ended December 31, 2022 2021 Weighted average remaining lease term (in years) 2.5 3.5 Weighted average discount rate percentage 3.50 % 3.50 %
Supplemental Cash Flow Information Related to Leases	Supplemental cash flow information related to leases under which the Company is the lessee was as follows (amounts in thousands): Years ended December 31, 2022 2021 Cash paid for amounts included in the measurement of operating leases $ 1,555 $ 1,374
Maturities of Operating Lease Liabilities	Maturities of operating lease liabilities as of December 31, 2022 were as follows (in thousands): Years ending December 31: Operating 2023 $ 1,636 2024 1,685 2025 845 Thereafter — Total future lease payments 4,166 Less imputed interest ( 184 ) Total operating lease liabilities $ 3,982

Stockholders equity (Tables)

Stockholders equity (Tables)	12 Months Ended
	Dec. 31, 2022
Equity [Abstract]
Schedule of Stock-Based Compensation Expense	Stock-based compensation expense recognized for all equity awards under the 2020 Plan has been reported in the consolidated statements of operations and comprehensive loss as follows (in thousands): Years ended December 31, 2022 2021 Research and development $ 5,419 $ 4,688 General and administrative 9,144 20,429 Total $ 14,563 $ 25,117
Summary of Restricted Stock Units	The following table summarizes RSU activity under the 2020 Plan for the years ended December 31, 2022 and 2021: Number of Weighted - Outstanding at December 31, 2020 1,920,037 $ — Granted — $ 18 Vested ( 944,991 ) $ — Outstanding at December 31, 2021 975,046 $ 18.00 Granted — $ — Vested ( 446,260 ) $ 18.00 Forfeited ( 18,747 ) Outstanding at December 31, 2022 510,039 $ 18.00
Summary of Stock Option Activity	The following table summarizes stock option activity under the 2020 Plan for the year ended December 31, 2022 and 2021 (in thousands, except share and per option data and years): Number of Weighted - Weighted - Aggregate Balance at December 31, 2020 615,106 $ 18.00 9.95 $ 9,848 Granted 479,543 $ 37.86 Exercised ( 7,747 ) $ 18.00 Balance at December 31, 2021 1,086,902 $ 26.76 9.22 $ 991,495 Granted 1,718,200 $ 6.35 Exercised — $ — — $ — Forfeited ( 50,387 ) $ 21.64 Expired ( 17,797 ) $ 40.00 Balance at December 31, 2022 2,736,918 $ 13.82 8.82 $ 3,636,148 Vested and expected to vest at December 31, 2022 2,736,918 $ 13.82 8.82 $ 3,636,148 Exercisable at December 31, 2022 496,074 $ 25.95 8.10 $ —
Summary of Assumptions Used in Black-Scholes Model	The assumptions used in the Black-Scholes option pricing model to determine the fair value of stock option grants were as follows: Years ended December 31, 2022 2021 Expected volatility 74.9 % 74.7 % Risk-free interest rate 2.14 % 1.06 % Expected dividend yield 0.0 % 0.0 % Expected term 6.04 years 5.98 years
Schedule of Common Stock Reserved for Future Issuance	Common stock reserved for future issuance are as follows in common equivalent shares: December 31, 2022 2021 Warrants for the purchase of common stock — 151,088 Common stock options and restricted stock units issued and outstanding 3,246,957 2,061,948 Awards available for future issuance under the 2020 Plan 3,012,554 3,211,854 Awards available for future issuance under the ESPP 1,070,402 822,811 Total common stock reserved for future issuance 7,329,913 6,247,701

Income taxes (Tables)

Income taxes (Tables)	12 Months Ended
	Dec. 31, 2022
Income Tax Disclosure [Abstract]
Schedule of Income Tax Reconciliation	A reconciliation of income tax expense computed at the U.S. federal statutory income tax rate to the Company’s income tax expense is as follows (in thousands): Years Ended December 31, 2022 2021 Tax computed at the federal statutory rate $ ( 22,361 ) $ ( 20,034 ) State income taxes, net of federal tax benefit ( 6 ) — Deferred impact of conversion to C Corporation — ( 2,131 ) Nondeductible executive compensation 685 4,145 Stock-based compensation 1,132 ( 1,021 ) Research and development and orphan drug credits ( 3,692 ) ( 3,091 ) Uncertain tax positions 910 757 Other, net ( 23 ) 793 Valuation allowance 23,355 20,582 Income tax expense $ — $ —
Schedule of Deferred Tax Assets and Liabilities	The Company’s net deferred tax assets (liabilities) are as follows (in thousands): Years Ended December 31, 2022 2021 Deferred tax assets: Net operating loss carryforwards $ 17,430 $ 21,935 Liability to licensor 4,159 4,159 Goodwill 3,193 3,449 Lease liability 836 1,128 Accrued compensation 659 485 Research credit carryforwards 5,760 2,945 Section 174 cost capitalization 14,523 — Section 59(e) cost capitalization 9,450 — Stock-based compensation 1,628 697 Other 3 2 Gross deferred tax assets 57,641 34,800 Less: valuation allowance ( 56,706 ) ( 33,351 ) Total deferred tax assets 935 1,449 Deferred tax liabilities: Fixed assets ( 426 ) ( 756 ) Operating lease right-of-use asset ( 509 ) ( 693 ) Total deferred tax liabilities ( 935 ) ( 1,449 ) Net deferred tax assets $ — $ —
Schedule of Unrecognized Tax Benefits	Years Ended December 31, 2022 2021 Unrecognized tax benefits - beginning $ 1,011 $ 210 Gross increases - tax positions in prior period 11 0 Gross increase – current-period tax positions 946 801 Unrecognized tax benefits - ending $ 1,968 $ 1,011

Organization and summary of s_4

Organization and summary of significant accounting policies - Additional Information (Details)	12 Months Ended
	Dec. 31, 2022 USD ($) NumberOfSegment shares	Dec. 31, 2021 USD ($) shares
Organization And Summary Of Significant Accounting Policies [Line Items]
Entity Incorporation, State or Country Code	DE
Company formation date	2007-03
Common Stock, Shares, Issued | shares	46,336,166	35,799,233
Preferred Stock, Shares Issued | shares	0	0
Accumulated deficit	$ (292,801,000)	$ (186,319,000)
Uncertain tax positions percentage	50%
Number of operating segment | NumberOfSegment	1
Impairment losses	$ 0	0
Operating lease right-of-use-assets	2,423,000	3,300,000
Operating lease liabilities	1,521,000	1,389,000
Operating lease liabilities, less current portion	2,460,000	$ 3,982,000
Accrued clinical trial cost	5,500,000
Accumulated deficit
Organization And Summary Of Significant Accounting Policies [Line Items]
Accumulated deficit	$ 292,800,000
Class B Common Stock
Organization And Summary Of Significant Accounting Policies [Line Items]
Common Stock, Shares, Issued | shares	1,211,959	1,492,059

Organization and summary of s_5

Organization and summary of significant accounting policies - Schedule of Earnings Per Share, Basic and Diluted (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Numerator:
Net loss	$ (106,482)	$ (95,402)
Denominator:
Weighted-average shares of common stock outstanding, diluted	38,927,268	34,561,245

Organization and summary of s_6

Organization and summary of significant accounting policies - Schedule of Anti-dilutive Securities Excluded from Calculation of Diluted Net Loss Per Share (Details) - shares	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from calculation of diluted net loss per share	3,260,327	2,213,036
Common stock warrants
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from calculation of diluted net loss per share	0	151,088
Common stock options
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from calculation of diluted net loss per share	2,736,918	1,086,902
Restricted Stock Units (RSUs)
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from calculation of diluted net loss per share	510,039	975,046
Employees Stock Purchase Plan Shares
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from calculation of diluted net loss per share	13,370

Balance sheet details - Schedul

Balance sheet details - Schedule of Prepaid Expenses Other Current Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Balance Sheet Related Disclosures [Abstract]
Prepaid research and development	$ 4,385	$ 1,811
Other prepaid expenses and current assets	539	502
Total	$ 4,924	$ 2,313

Balance sheet details - Sched_2

Balance sheet details - Schedule of Property and Equipment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Property And Equipment [Line Items]
Property and equipment, gross	$ 8,092	$ 7,933
Less accumulated depreciation and amortization	(5,364)	(4,257)
Total	2,728	3,676
Furniture Fixtures and Office Equipment
Property And Equipment [Line Items]
Property and equipment, gross	$ 2,140	$ 2,123
Laboratory Equipment
Property And Equipment [Line Items]
Property and equipment useful life	5 years	5 years
Property and equipment, gross	$ 2,265	$ 2,123
Leasehold Improvements
Property And Equipment [Line Items]
Property and equipment, gross	$ 3,687	$ 3,687
Minimum | Furniture Fixtures and Office Equipment
Property And Equipment [Line Items]
Property and equipment useful life	3 years	3 years
Minimum | Leasehold Improvements
Property And Equipment [Line Items]
Property and equipment useful life	2 years	2 years
Maximum | Furniture Fixtures and Office Equipment
Property And Equipment [Line Items]
Property and equipment useful life	7 years	7 years
Maximum | Leasehold Improvements
Property And Equipment [Line Items]
Property and equipment useful life	3 years	3 years

Balance sheet details - Sched_3

Balance sheet details - Schedule of Accounts Payable and Accrued Expenses (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Balance Sheet Related Disclosures [Abstract]
Accounts payable	$ 4,231	$ 1,179
Accrued compensation	3,451	2,671
Accrued research and development	12,649	13,501
Other accrued expenses	1,279	1,073
Total	$ 21,610	$ 18,424

Fair value measurements - Addit

Fair value measurements - Additional Information (Details) - USD ($)	Dec. 31, 2022	Dec. 31, 2021
Fair Value Disclosures [Abstract]
Assets measured at fair value	$ 0	$ 0
Liability measured at fair value	$ 0	$ 0

Debt - Additional Information (

Debt - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Debt Instrument [Line Items]
interest expense	$ 0	$ 3
Debt description	The Company did not have any outstanding debt as of December 31, 2022 or December 31, 2021. In April 2020, the Company borrowed $0.7 million under the Paycheck Protection Program (“PPP”) under the CARES Act. The loan was subsequently forgiven in July 2021. The $0.7 million balance of the forgiven loan was recognized as other income on the Company's Statement of Operations and Comprehensive Loss for the twelve months ended December 31, 2021
Gain on extinguishment of long-term debt	$ 0	690
Debt Conversion, Description	The Company did not have any outstanding debt as of December 31, 2022 or December 31, 2021. In April 2020, the Company borrowed $0.7 million under the Paycheck Protection Program (“PPP”) under the CARES Act. The loan was subsequently forgiven in July 2021. The $0.7 million balance of the forgiven loan was recognized as other income on the Company's Statement of Operations and Comprehensive Loss for the twelve months ended December 31, 2021
Debt Instrument Outstanding Principal Amount	$ 0	0
Gain on extinguishment of debt	$ 0	(690)
PPP Loan
Debt Instrument [Line Items]
Debt Instrument Outstanding Principal Amount			$ 700
Other Debt(PPP)
Debt Instrument [Line Items]
Gain on extinguishment of long-term debt		700
Gain on extinguishment of debt		$ (700)

Leases - Additional Information

Leases - Additional Information (Details)	12 Months Ended
	Dec. 31, 2021
Leases [Abstract]
Additional extended term	5 years
Lessor, operating lease, option to extend	The lease expires in July 2025 and the Company has an option to extend the term of the lease for an additional five years. However, it is not reasonably certain the Company will exercise the option to renew when the lease term ends and thus, the incremental term was excluded from the calculation of the lease liability. Additionally, the

Leases - Components of Lease Ex

Leases - Components of Lease Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Leases [Abstract]
Operating lease expense	$ 1,043	$ 1,043
Variable lease expense	460	512
Total lease expense, net	$ 1,503	$ 1,555

Leases - Summary of Weighted Av

Leases - Summary of Weighted Average Remaining Lease Term And Weighted Average Discount Rate (Details)	Dec. 31, 2022	Dec. 31, 2021
Leases [Abstract]
Weighted average remaining lease term (in years)	2 years 6 months	3 years 6 months
Weighted average discount rate percentage	3.50%	3.50%

Leases - Supplemental Cash Flow

Leases - Supplemental Cash Flow Information Related to Leases (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Leases [Abstract]
Cash paid for amounts included in the measurement of operating leases	$ 1,555	$ 1,374

Leases - Maturities of Operatin

Leases - Maturities of Operating Lease Liabilities (Details) $ in Thousands	Dec. 31, 2022 USD ($)
Leases [Abstract]
2023	$ 1,636
2024	1,685
2025	845
Thereafter	0
Total future lease payments	4,166
Less imputed interest	(184)
Total operating lease liabilities	$ 3,982

Stockholders' equity - Addition

Stockholders' equity - Additional Information (Details) - USD ($)		1 Months Ended			12 Months Ended
	Jan. 01, 2021	Nov. 30, 2022	Mar. 31, 2022	Sep. 30, 2021	Dec. 31, 2022	Dec. 31, 2021	Nov. 08, 2022	Dec. 31, 2020
Class Of Stock [Line Items]
Preferred Stock, Shares Issued					0	0
Common Stock, Shares, Issued					46,336,166	35,799,233
Preferred Stock, Shares Authorized					200,000,000	200,000,000
Preferred Stock, Par or Stated Value Per Share					$ 0.0001	$ 0.0001
Common Stock, Shares Authorized					350,000,000	350,000,000
Common Stock, Par or Stated Value Per Share					$ 0.0001	$ 0.0001
Conversion of stock, description					Holders of the Company’s common stock have no conversion rights, while holders of the Company’s Class B common stock shall have the right to convert each share of Class B common stock into one share of common stock at such holder’s election, provided that as a result of such conversion, such holder would not beneficially own in excess of 4.99% of any class of the Company’s securities registered under the Securities Exchange Act of 1934
Period related to changing of ownership limitation percentage designated by Class B common stock holder					61 days
Warrants Expired And Unexercised			151,088			566,586
Vesting period			450 days			365 days
Fair value of options, vested					$ 6,900	$ 1,900,000
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition					1 year 3 months 18 days
Total number of common shares reserved for issuance					7,329,913	6,247,701
Equity Option
Class Of Stock [Line Items]
Share-based Payment Arrangement, Nonvested Award, Option, Cost Not yet Recognized, Amount					$ 14,900,000
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition					2 years 10 months 24 days
Share Based Compensation Arrangement By Share Based Payment Award Options Grants In Period Weighted Average Grant Date Fair Value					$ 4.06	$ 24.61
Restricted Stock Units (RSUs)
Class Of Stock [Line Items]
Number of outstanding shares					510,039	975,046		1,920,037
Share-based Payment Arrangement, Nonvested Award, Option, Cost Not yet Recognized, Amount					$ 9,200
Private Placement of Common Stock
Class Of Stock [Line Items]
Sale of stock price per share				$ 28
Common Stock, Shares, Issued				2,678,600
Proceeds from the Private Placement, net of underwriting discounts and commissions and other offering costs				$ 71,000
2020 Equity Incentive Plan
Class Of Stock [Line Items]
Common shares authorized for issuance					7,658,509	6,226,540
Shares available for awards, description	4
Vesting percentage					25%
Vesting period					36 months
Vesting terms, description					ten years
Employees Stock Purchase Plan Shares
Class Of Stock [Line Items]
Common Stock, Shares, Issued					147,564	11,182
Common Stock, Shares Authorized					1,229,148	833,993
Purchase common stock through payroll deductions of up to compensations, percent					15%
Share Based Compensation Arrangement By Share Based Payment Award Percentage Of Outstanding Stock Maximum					1%
Increase in issuance of common stock					929,658
Total number of common shares reserved for issuance					1,070,402
Stock-based compensation expense					$ 200,000	$ 100,000
November 2022 Underwritten Offering
Class Of Stock [Line Items]
Sale of stock price per share							$ 6.67
Common Stock, Shares, Issued							9,745,128
Proceeds from Underwritten Offering, net of underwriting discounts and commissions and other offering costs		$ 61,700
IPO
Class Of Stock [Line Items]
Vesting terms, description					The warrants became exercisable upon our IPO for a period of 365 and 450 days
Class B Common Stock
Class Of Stock [Line Items]
Common Stock, Shares, Issued					1,211,959	1,492,059
Common Stock, Shares Authorized					15,368,569	15,368,569
Common Stock, Par or Stated Value Per Share					$ 0.0001	$ 0.0001
Common Stock
Class Of Stock [Line Items]
Common stock, voting rights					one

Stockholders' equity - Schedule

Stockholders' equity - Schedule of Stock-based Compensation Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Class Of Stock [Line Items]
Stock-based compensation	$ 14,563	$ 25,117
Research and Development Expense
Class Of Stock [Line Items]
Stock-based compensation	5,419	4,688
General and Administrative Expense
Class Of Stock [Line Items]
Stock-based compensation	$ 9,144	$ 20,429

Stockholders' equity - Summary

Stockholders' equity - Summary of Restricted Stock Units (Details) - Restricted Stock Units (RSUs) - $ / shares	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Class Of Stock [Line Items]
Number of Outstanding Shares, Beginning Balance	975,046	1,920,037
Number of Shares, Granted	0	0
Number of Shares, Vested	(446,260)	(944,991)
Number of Shares, forfeited	(18,747)
Number of Outstanding Shares, Ending Balance	510,039	975,046
Weighted Average Grant Date Fair Value, Beginning Balance	$ 18	$ 0
Weighted Average Grant Date Fair Value, Granted	0	18
Weighted Average Grant Date Fair Value, Vested	18	0
Weighted Average Grant Date Fair Value, Ending Balance	$ 18	$ 18

Stockholders' equity - Summar_2

Stockholders' equity - Summary of Stock Option Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock Options Outstanding, Beginning Balance, Number of Shares	1,086,902	615,106
Granted, Number of Shares		479,543
Exercised, Number of Shares	0	(7,747)
Forfeiture, Number of Shares	(50,387)
Expired, Number of Shares	(17,797)
Exercisable, Number of Shares	496,074
Stock Options Outstanding, Ending Balance, Number of Shares	2,736,918	1,086,902	615,106
Vested and expected to vest, Number of Shares	2,736,918
Outstanding, Beginning Balance, Weighted-Average Exercise Price per Share	$ 26.76
Granted, Weighted-Average Exercise Price per Share		$ 37.86
Exercised, Weighted average exercise price per option	0	18
Forfeited, Weighted average exercise price per option	21.64
Expired, Weighted average exercise price per option	40
Exercisable, Weighted average exercise price per option	25.95
Outstanding, Ending Balance, Weighted-Average Exercise Price per Share | $ / shares		$ 26.76
Vested and expected to vest, Weighted-Average Exercise Price per Share	$ 13.82
Outstanding, Weighted-Average Remaining Contractual Term (years)	8 years 9 months 25 days	9 years 2 months 19 days	9 years 11 months 12 days
Vested and expected to vest, Weighted-Average Remaining Contractual Term (years)	8 years 9 months 25 days
Exercisable, Weighted-Average Remaining Contractual Term (years)	8 years 1 month 6 days
Outstanding, Aggregate Intrinsic Value	$ 991,495	$ 9,848
Outstanding, Aggregate Intrinsic Value		$ 991,495	$ 9,848
Vested and expected to vest, Aggregate Intrinsic Value	3,636,148
Exercisable, Aggregate Intrinsic	$ 0
Equity Option
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Granted, Number of Shares	1,718,200
Outstanding, Beginning Balance, Weighted-Average Exercise Price per Share		$ 18
Granted, Weighted-Average Exercise Price per Share	$ 6.35
Outstanding, Ending Balance, Weighted-Average Exercise Price per Share | $ / shares	$ 13.82		$ 18
Outstanding, Aggregate Intrinsic Value	$ 3,636,148

Stockholders' equity - Summar_3

Stockholders' equity - Summary of Assumptions Used in Black-Scholes Model (Details)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Stockholders' Equity Note [Abstract]
Expected volatility	74.90%	74.70%
Risk-free interest rate	2.14%	1.06%
Expected dividend yield	0%	0%
Expected term	6 years 14 days	5 years 11 months 23 days

Stockholders' equity - Schedu_2

Stockholders' equity - Schedule of Common Stock Reserved for Future Issuance (Details) - shares	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Class Of Stock [Line Items]
Common Stock, Shares, Issued	46,336,166	35,799,233
Common Stock, Shares, Outstanding	46,336,166	35,799,233
Total number of common shares reserved for issuance	7,329,913	6,247,701
Warrants [Member]
Class Of Stock [Line Items]
Warrants for the purchase of common stock	0	151,088
Common Stock Options and Restricted Stock Units [Member]
Class Of Stock [Line Items]
Common Stock, Shares, Issued	3,246,957	2,061,948
Common Stock, Shares, Outstanding	3,246,957	2,061,948
2020 Plan [Member]
Class Of Stock [Line Items]
Awards	3,012,554	3,211,854
Employees Stock Purchase Plan Shares
Class Of Stock [Line Items]
Common Stock, Shares, Issued	147,564	11,182
Awards	1,070,402	822,811
Total number of common shares reserved for issuance	1,070,402

Collaboration, license and op_2

Collaboration, license and option agreements - Additional Information (Details) - USD ($) $ in Thousands		12 Months Ended
	Nov. 18, 2021	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2019
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Collaboration Amendment Date				2019-03
Revenues			$ 300
Liability to licensor		$ 19,806	19,806
BeiGene
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Collaboration Amendment Date		2021-11
Upfront Non-Refundable Payment				$ 25,000
Revenues		$ 0
License termination information, Description	In the event the license is terminated, the liability will be extinguished with no further payment to BeiGene.
Current portion of deferred revenue	$ 19,800
Liability to licensor		$ 19,800	$ 19,800

Related party transactions - Ad

Related party transactions - Additional Information (Details) - USD ($)			12 Months Ended
	Mar. 23, 2021	Jul. 07, 2020	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Jan. 01, 2020
Related Party Transaction [Line Items]
Research and development expense			$ 79,347,000	$ 58,274,000
Related party transaction, terms and manner of settlement			(i) a lump sum payment equal to 18 months of Ms. Anderson Short’s then-current base salary, (ii) a payment at her targeted bonus rate for 2021, pro-rated to the date of her termination of employment, and (iii) full accelerated vesting of her equity awards including 7,747 stock options and 138,461 restricted stock units. The modification of these equity awards resulted in an incremental fair value of $7.0 million which was recognized on a straight-line basis over the transition service period which ended on the separation date. For the year ended December 31, 2021, the Company recognized $1.0 million related to the lump sum salary payment and target bonus. The Company also recognized non-cash stock-based compensation charges of $9.4 million related to the modified equity awards for the year ended December 31, 2021. No unrecognized stock-based compensation related to the transition agreement was recognized for the year ended December 31, 2022.
Non-cash stock-based compensation charges			$ 14,563,000	$ 25,117,000
Common Stock, Shares, Issued			46,336,166	35,799,233
Exercised, Number of Shares			0	7,747
Forfeited, Number of Shares			2,736,918	1,086,902	615,106
Carolyn Anderson Short
Related Party Transaction [Line Items]
Number of accelerated full vesting equity awards including stock options	7,747
Number of accelerated full vesting equity awards including restricted stock units	138,461
Incremental Fair Value				$ 7,000,000
Expense related to Lump Sum Salary Payment and Target Bonus				1,000,000
Non-cash stock-based compensation charges				$ 9,400,000
Unrecognized stock-based compensation			$ 0
Private Placement of Common Stock
Related Party Transaction [Line Items]
Common Stock, Shares, Issued				625,000
Net proceeds Issuance Of private placement				$ 17,500,000
November 2022 Underwritten Offering
Related Party Transaction [Line Items]
Common Stock, Shares, Issued			2,998,500
Net proceeds Issuance Of private placement			$ 19,100,000
Inversagen L L C
Related Party Transaction [Line Items]
Royalty Expense		$ 0
Options grants related to royalty payment, Period			10 years
Assets or liabilities associated with related party variable interest			$ 0	0
Himalaya Therapeutics S E Z C
Related Party Transaction [Line Items]
Research and development expense			400,000
Royalty Expense			$ 0
Description Of Agreement With Related Party			In April 2022, the Company entered into a Clinical Trial Agreement with Himalaya Therapeutics SEZC. Under the agreement, Himalaya Therapeutics SEZC agreed to provide services related to the initiation of clinical trials for BA3011 in the People’s Republic of China. For the first year following effectiveness of the agreement, the Company has agreed to pay Himalaya Therapeutics SEZC for the full-time use of two of its personnel. Payments are due and payable by BioAtla to Himalaya Therapeutics SEZC on a quarterly calendar basis and are non-refundable. For the twelve months ended December 31, 2022, the Company recognized $0.4 million in research and development expense related to the Clinical Trial Agreement. The Company did not have any amounts due from or due to Himalaya Therapeutics SEZC as of December 31, 2022.
Assets or liabilities associated with related party variable interest					$ 0
Bio Atla Holdings L L C
Related Party Transaction [Line Items]
Assets or liabilities associated with related party variable interest			$ 0	$ 0
Options grants related to royalty payments, Period		10 years
Equity Interest In Related Party						50%

401(k) plan - Additional Inform

401(k) plan - Additional Information (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2022 USD ($)
Retirement Benefits [Abstract]
Contributions made by company	$ 0

Income taxes - Schedule of Inco

Income taxes - Schedule of Income Tax Reconciliation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Income Tax Disclosure [Abstract]
Tax computed at the federal statutory rate	$ (22,361)	$ (20,034)
State income taxes, net of federal tax benefit	(6)	0
Deferred impact of conversion to C Corporation		(2,131)
Nondeductible executive compensation	685	4,145
Stock-based compensation	1,132	(1,021)
Research and development and orphan drug credits	(3,692)	(3,091)
Uncertain tax positions	910	757
Other, net	(23)	793
Valuation allowance	23,355	20,582
Income tax expense	$ 0	$ 0

Income taxes - Schedule of Defe

Income taxes - Schedule of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Deferred tax assets:
Net operating loss carryforwards	$ 17,430	$ 21,935
Liability to licensor	4,159	4,159
Goodwill	3,193	3,449
Lease liability	836	1,128
Accrued compensation	659	485
Research credit carryforwards	5,760	2,945
Section 174 cost capitalization	14,523	0
Section 59(e) cost capitalization	9,450	0
Stock-based compensation	1,628	697
Other	3	2
Gross deferred tax assets	57,641	34,800
Less valuation allowance	(56,706)	(33,351)
Total deferred tax assets	935	1,449
Deferred tax liabilities:
Fixed assets	(426)	(756)
Operating lease right-of-use asset	(509)	(693)
Total deferred tax liabilities	(935)	(1,449)
Net deferred tax assets	$ 0	$ 0

Income taxes - Additional Infor

Income taxes - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Operating Loss Carryforwards [Line Items]
Deferred tax asset valuation allowance	$ 56,706,000	$ 33,351,000
Change in Valuation Allowance	23,400,000
state net operating loss carryforwards	$ 200
Tax credit limitation on use	The federal and state net operating losses can be carried forward indefinitely, subject to an 80% limitation against taxable income.
Tax Credit Carryforward, Amount	$ 3,700,000
Orphan Drug Credit	$ 2,300,000
Use of annual operating loss carryforwards	Sections 382 and 383, annual use of the Company’s net operating loss carryforwards may be limited in the event a cumulative change in ownership of more than 50% occurs within a three-year period.
CARES Act NOL carryover/carryback offset to taxable income.	50%
Unrecognized tax benefits	$ 1,968,000	$ 1,011,000	$ 210,000
PPP Loan
Operating Loss Carryforwards [Line Items]
Proceeds from loans	$ 700,000
Domestic Tax Authority
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards Expiration Period	2040
orphan drug credit carryforwards Expiration Period	2041
Domestic Tax Authority | Research and Development Tax Credit
Operating Loss Carryforwards [Line Items]
Federal net operating loss carryforward	$ 83,000,000
California Franchise Tax Board | Research and Development Tax Credit
Operating Loss Carryforwards [Line Items]
Tax Credit Carryforward, Amount	$ 2,000,000

Income taxes - Schedule of Unre

Income taxes - Schedule of Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Income Tax Disclosure [Abstract]
Beginning Balance	$ 1,011	$ 210
Gross increases - tax positions in prior period	11	0
Gross increase - current-period tax positions	946	801
Ending Balance	$ 1,968	$ 1,011

Subsequent events - Additional

Subsequent events - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended
	Jan. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Subsequent Event [Line Items]
Common stock par value per share		$ 0.0001	$ 0.0001
Subsequent Event | Jefferies LLC
Subsequent Event [Line Items]
Common stock par value per share	$ 0.0001
Subsequent Event | Maximum | Jefferies LLC
Subsequent Event [Line Items]
Maximum potential proceeds from sale of equity	$ 100,000,000