0000950170-24-036548 | 10-K | XBRL Viewer

401(k) plan	12 Months Ended
Dec. 31, 2023
Retirement Benefits [Abstract]
401(k) plan	. 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 not made any matching contributions.

Balance sheet details - Schedule of Accounts Payable and Accrued Expenses (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Balance Sheet Related Disclosures [Abstract]
Accounts payable	$ 3,819	$ 4,231
Accrued compensation	3,790	3,451
Accrued research and development	18,246	12,649
Other accrued expenses	865	1,279
Total	$ 26,720	$ 21,610

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Current assets:
Cash and cash equivalents	$ 111,471	$ 215,507
Prepaid expenses and other current assets	4,935	4,924
Total current assets	116,406	220,431
Property and equipment, net	1,603	2,728
Operating lease right-of-use-asset, net	1,495	2,423
Other assets	154	154
Total assets	119,658	225,736
Current liabilities:
Accounts payable and accrued expenses	26,720	21,610
Operating lease liabilities	1,624	1,521
Total current liabilities	28,344	23,131
Operating lease liabilities, less current portion	836	2,460
Liability to licensor	19,806	19,806
Total liabilities	48,986	45,397
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	0	0
Common stock value	5	5
Additional paid-in capital	486,930	473,135
Accumulated deficit	(416,263)	(292,801)
Total stockholders' equity	70,672	180,339
Total liabilities and stockholders' equity	$ 119,658	$ 225,736

Income taxes

12 Months Ended

Dec. 31, 2023

Income Tax Disclosure [Abstract]

Income taxes

. 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,
	2023			2022
Tax computed at the federal statutory rate	$	(25,927	)	$	(22,361	)
State income taxes, net of federal tax benefit		(8	)		(6	)
Nondeductible executive compensation		99			685
Stock-based compensation		1,326			1,132
Research and development and orphan drug credits		(6,205	)		(3,692	)
Uncertain tax positions		1,551			910
Other, net		228			(23	)
Valuation allowance		28,936			23,355
Income tax expense	$	—		$	—

The Company’s net deferred tax assets (liabilities) are as follows (in thousands):


	Years Ended December 31,
	2023			2022
Deferred tax assets:
Net operating loss carryforwards	$	25,034		$	17,430
Liability to licensor		4,159			4,159
Goodwill		2,938			3,193
Lease liability		517			836
Accrued compensation		746			659
Research credit carryforwards		10,379			5,760
Section 174 cost capitalization		31,220			14,523
Section 59(e) cost capitalization		8,400			9,450
Stock-based compensation		2,790			1,628
Other		4			3
Gross deferred tax assets		86,187			57,641
Less: valuation allowance		(85,642	)		(56,706	)
Total deferred tax assets		545			935
Deferred tax liabilities:
Fixed assets		(231	)		(426	)
Operating lease right-of-use asset		(314	)		(509	)
Total deferred tax liabilities		(545	)		(935	)
Net deferred tax assets	$	—		$	—

A valuation allowance of approximately $85.6 million as of December 31, 2023 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 $28.9 million during 2023.

At December 31, 2023, the Company had federal and state net operating loss carryforwards of approximately $119.2 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. The state net operating losses will begin to expire in 2042, unless previously utilized.

At December 31, 2023, the Company had federal and California research and development credit carryforwards of approximately $7.8 million and $2.7 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, 2023, the Company also had federal orphan drug credit carryforwards of approximately $3.9 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.

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 further clarification 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,
	2023		2022
Unrecognized tax benefits - beginning	$	1,968	$	1,011
Gross increases - tax positions in prior period		161		11
Gross increase – current-period tax positions		1,473		946
Unrecognized tax benefits - ending	$	3,602	$	1,968

As of December 31, 2023, the Company had gross unrecognized tax benefits of approximately $3.6 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 balance sheet and has not recognized interest or penalties in the statements of operations and comprehensive income for the year ended December 31, 2023. 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 2020 and 2019, 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.

- Definition

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

+ References

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+ Details

Organization and summary of significant accounting policies - Additional Information (Details)	1 Months Ended	12 Months Ended
	Jan. 31, 2023 USD ($)	Dec. 31, 2023 USD ($) shares	Dec. 31, 2022 USD ($) NumberOfSegment 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		48,077,599	46,336,166
Preferred Stock, Shares Issued \| shares		0	0
Accumulated deficit		$ (416,263,000)	$ (292,801,000)
Maximum aggregate gross sale proceeds		$ 0	$ 61,682,000
Uncertain tax positions percentage		50.00%
Number of operating segment \| NumberOfSegment			1
Impairment losses		$ 0	$ 0
Cash and cash equivalents		50,400,000	0
Operating lease right-of-use-assets		1,495,000	2,423,000
Operating lease liabilities		1,624,000	1,521,000
Operating lease liabilities, less current portion		836,000	2,460,000
Accrued clinical trial cost		$ 12,500,000
Accumulated deficit
Organization And Summary Of Significant Accounting Policies [Line Items]
Accumulated deficit			$ 416,300,000
Maximum aggregate gross sale proceeds	$ 100,000,000
Class B Common Stock
Organization And Summary Of Significant Accounting Policies [Line Items]
Common Stock, Shares, Issued \| shares		0	1,211,959

Leases (Tables)

12 Months Ended

Dec. 31, 2023

Lessee Disclosure [Abstract]

Components of Lease Expense

The components of lease expense included in the Company’s statements of operations and loss include (in thousands):


	Years ended December 31,
	2023		2022
Operating lease expense	$	1,043	$	1,043
Variable lease expense		544		460
Total lease expense, net	$	1,587	$	1,503

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 were as follows:


	December 31,
	2023			2022
Weighted average remaining lease term (in years)		1.5			2.5
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,
	2023		2022
Cash paid for amounts included in the measurement of operating leases	$	1,500	$	1,555

Maturities of Operating Lease Liabilities

Maturities of operating lease liabilities as of December 31, 2023 were as follows (in thousands):


Years ending December 31:	Operating lease
2024	$	1,685
2025		845
Thereafter		—
Total future lease payments		2,530
Less imputed interest		(70	)
Total operating lease liabilities	$	2,460

Organization and summary of significant accounting policies

12 Months Ended

Dec. 31, 2023

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, its CAB immune-oncology antibody targeting CTLA-4, and its CAB bispecific antibody targeting EpCAM.

Basis of Presentation

The accompanying 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 8).

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, 2023, the Company had an accumulated deficit of $416.3 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.

In January 2023, the Company entered into an Open Market Sale Agreement (the “Sales Agreement”) with Jefferies LLC pursuant to which the Company may, from time to time at its sole discretion, sell shares of the Company’s common stock, with aggregate gross sales proceeds of up to $100.0 million. The Company has not sold any shares of its common stock under the Sales Agreement as of December 31, 2023.

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 as its current cash and cash equivalents will be sufficient to fund the Company’s operations for a period of at least one year from the issuance date of these financial statements.

Variable Interest Entities (“VIE”)

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 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 8).

Use of Estimates

The Company’s financial statements are prepared in accordance with U.S. GAAP. The preparation of the Company’s 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 financial statements and accompanying notes. The most significant estimates in the Company’s financial statements relate to 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 90 days or less at the date of purchase to be cash equivalents. Cash equivalents consist of highly rated securities including U.S. Government and U.S. Treasury money market funds, which are unrestricted as to withdrawal or use. The cash and cash equivalents balance as of December 31, 2023 and 2022 includes $50.4 million and $0, respectively, invested in U.S. Government and U.S. Treasury money market funds.

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 and may invest cash that is not required for immediate operating needs in highly liquid instruments that bear minimal risk. 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 not recognized any impairment losses for the years ended December 31, 2023 and 2022.

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. 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 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 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, 2023, the Company has accrued $12.5 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 and assumptions 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. A modification in the protocol of a clinical trial or cancellation of a trial could result in a material 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 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 BioAtla, Inc. Employee Stock Purchase Plan (the “ESPP”).

Potentially dilutive securities not included in the calculation of diluted net loss per common share because to do so would be anti-dilutive are as follows (in common stock equivalents):


	December 31,
	2023		2022
Common stock options		6,273,507		2,736,918
Restricted stock units		99,104		510,039
ESPP Shares		57,253		13,370
Total		6,429,864		3,260,327

Recent Accounting Pronouncements

In December 2023, the FASB issued ASU No. 2023-09, “Income Taxes (Topic 740): Improvements to Income Tax Disclosures”. ASU 2023-09 requires disaggregated information about a reporting entity's effective tax rate reconciliation as well as information on income taxes paid. ASU 2023-09 is effective for public entities with annual periods beginning after December 15, 2024, with early adoption permitted. The Company is currently evaluating the impact of this guidance on its financial statements.

Related party transactions - Additional Information (Details) - USD ($)		12 Months Ended
	Jul. 07, 2020	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2020	Jan. 01, 2020
Related Party Transaction [Line Items]
Research and development expense		$ 103,731,000	$ 79,347,000
Common Stock, Shares, Issued		48,077,599	46,336,166
Related Party \| 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		$ 100,000	400,000
Extended Rent Agreement		12 months
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 mecbotamab vedotin 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 were due and payable by BioAtla to Himalaya Therapeutics SEZC on a quarterly calendar basis and are non-refundable. The Company made its final payment under the agreement in January 2023. For the twelve months ended December 31, 2023 and 2022, the Company recognized $0.1 million and $0.4 million in research and development expense related to the Clinical Trial Agreement, respectively. The Company did not have any amounts due from or due to Himalaya Therapeutics SEZC as of December 31, 2023.
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
Share of Royalties under Royalty Sharing Agreement					50.00%

Balance sheet details (Tables)

12 Months Ended

Dec. 31, 2023

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,
	2023		2022
Prepaid research and development	$	4,615	$	4,385
Other prepaid expenses and current assets		320		539
Total	$	4,935	$	4,924

Schedule of Property and Equipment

Property and equipment consist of the following (in thousands):


		December 31,
	Useful life (years)	2023			2022
Furniture, fixtures and office equipment	3 - 7	$	1,721		$	2,140
Laboratory equipment	5		2,280			2,265
Leasehold improvements	2 - 3		3,680			3,687
			7,681			8,092
Less accumulated depreciation and amortization			(6,078	)		(5,364	)
Total		$	1,603		$	2,728

Schedule of Accounts Payable and Accrued Expenses

Accounts payable and accrued expenses consist of the following (in thousands):


	December 31,
	2023		2022
Accounts payable	$	3,819	$	4,231
Accrued compensation		3,790		3,451
Accrued research and development		18,246		12,649
Other accrued expenses		865		1,279
Total	$	26,720	$	21,610

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Cash flows from operating activities
Net Income (Loss)	$ (123,462)	$ (106,482)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	1,221	1,199
Loss on disposal of property and equipment	2	13
Stock-based compensation	13,544	14,563
Changes in operating assets and liabilities:
Prepaid expenses and other assets	(11)	(2,611)
Accounts payable and accrued expenses	5,284	3,411
Right-of-use assets and lease liabilities, net	(593)	(513)
Net cash used in operating activities	(104,015)	(90,420)
Cash flows from investing activities
Purchases of property and equipment	(98)	(268)
Proceeds from sale of property and equipment	0	3
Net cash used in investing activities	(98)	(265)
Cash flows from financing activities
Proceeds from issuance of common stock, net of issuance costs	0	61,682
Proceeds from issuance of common stock under Employee Stock Purchase Plan	336	289
Payments for taxes related to net settlement of equity awards	(259)	(758)
Net cash provided by financing activities	77	61,213
Net decrease in cash and cash equivalents	(104,036)	(29,472)
Cash and cash equivalents, beginning of period	215,507	244,979
Cash and cash equivalents, end of period	111,471	215,507
Supplemental disclosure of non-cash investing and financing activities
Property and equipment additions included in accounts payable and accrued expenses	0	1
Tax related to net settlement of equity award included in accounts payable and accrued expenses	$ 6	$ 67

Collaboration, license and option agreements - Additional Information (Details) - USD ($) $ in Thousands		12 Months Ended			36 Months Ended
	Nov. 18, 2021	Dec. 31, 2023	Dec. 31, 2021	Dec. 31, 2019	Dec. 31, 2021	Dec. 31, 2022
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Collaboration Amendment Date				2019-04
Retained Earnings (Accumulated Deficit)		$ (416,263)				$ (292,801)
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

- Definition

Amount of accumulated undistributed earnings (deficit).

+ References + Details

- Definition

Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss).

+ References

+ Details

Balance sheet details

12 Months Ended

Dec. 31, 2023

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,
	2023		2022
Prepaid research and development	$	4,615	$	4,385
Other prepaid expenses and current assets		320		539
Total	$	4,935	$	4,924

Property and equipment consist of the following (in thousands):


		December 31,
	Useful life (years)	2023			2022
Furniture, fixtures and office equipment	3 - 7	$	1,721		$	2,140
Laboratory equipment	5		2,280			2,265
Leasehold improvements	2 - 3		3,680			3,687
			7,681			8,092
Less accumulated depreciation and amortization			(6,078	)		(5,364	)
Total		$	1,603		$	2,728

Accounts payable and accrued expenses consist of the following (in thousands):


	December 31,
	2023		2022
Accounts payable	$	3,819	$	4,231
Accrued compensation		3,790		3,451
Accrued research and development		18,246		12,649
Other accrued expenses		865		1,279
Total	$	26,720	$	21,610

Related party transactions

12 Months Ended

Dec. 31, 2023

Related party transactions

. Related party transactions

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; the 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 not have any assets or liabilities associated with its variable interest in Inversagen at December 31, 2023 and 2022.

Inversagen is a related party of the Company. Dr. Jay Short and his spouse 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 from its Exclusive License Agreement with EXUMA Biotech Corp.

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 not have any assets or liabilities associated with its variable interests in BioAtla Holdings at December 31, 2023 and 2022.

BioAtla Holdings is a related party of the Company. Dr. Jay Short and his spouse 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 VIE 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 not have any assets or liabilities recorded at December 31, 2023 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 serve as directors, and Dr. Short's spouse 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 mecbotamab vedotin 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 were due and payable by BioAtla to Himalaya Therapeutics SEZC on a quarterly calendar basis and are non-refundable. The Company made its final payment under the agreement in January 2023. For the twelve months ended December 31, 2023 and 2022, the Company recognized $0.1 million and $0.4 million in research and development expense related to the Clinical Trial Agreement, respectively. The Company did not have any amounts due from or due to Himalaya Therapeutics SEZC as of December 31, 2023. In January 2024, the Clinical Trial Agreement was amended to extend the agreement for 12 additional months. Under the amended agreement, BioAtla will pay Himalaya Therapeutics SEZC for the full-time use of two of its personnel and provide services related to the initiation of clinical trials for evalstotug in China.

Himalaya Parent LLC

Dr. Jay Short and his spouse serve as managers of Himalaya Parent LLC. The Company does not have a variable interest in Himalaya Parent LLC.

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.

- Definition

The entire disclosure for related party transactions. Examples of related party transactions include transactions between (a) a parent company and its subsidiary; (b) subsidiaries of a common parent; (c) and entity and its principal owners; and (d) affiliates.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480990/946-20-50-2

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 5
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480990/946-20-50-5

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480990/946-20-50-6

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 235
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481062/946-235-50-2

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 235
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (e)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481062/946-235-50-2

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 850
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483326/850-10-50-1

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.6-07(2)(g)(3))
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-URI https://asc.fasb.org//1943274/2147483575/946-220-S99-1

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
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-Name Accounting Standards Codification
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-Paragraph 1
-Subparagraph (SX 210.6-07(2)(c))
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-URI https://asc.fasb.org//1943274/2147483575/946-220-S99-1

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
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-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.6-07(2)(e))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483575/946-220-S99-1

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Topic 850
-Name Accounting Standards Codification
-Publisher FASB
-URI https://asc.fasb.org//850/tableOfContent

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Topic 850
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483326/850-10-50-6

Reference 12: http://www.xbrl.org/2003/role/disclosureRef
-Topic 850
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-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483326/850-10-50-1

Reference 13: http://www.xbrl.org/2003/role/disclosureRef
-Topic 850
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483326/850-10-50-1

+ Details

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	Accumulated deficit
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, net of issuance costs	61,682		$ 1	61,681
Issuance of common stock, net of issuance costs, shares			9,745,128
Issuance of common stock under equity incentive plans, net of shares withheld for taxes, shares			364,141
Issuance of common stock for Employee Stock Purchase Plan	289			289
Issuance of common stock for Employee Stock Purchase Plan, shares			147,564
Taxes related to net share settlement of equity awards	(534)			(534)
Conversion of Class B Common Stock, Shares		(280,100)	280,100
Conversion of Class B Common Stock	0			0
Stock-based compensation	14,563			14,563
Net Income (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
Issuance of common stock under equity incentive plans, net of shares withheld for taxes, shares			318,634
Issuance of common stock for Employee Stock Purchase Plan	336			336
Issuance of common stock for Employee Stock Purchase Plan, shares			165,550
Issuance of common stock for director compensation(value)	107			107
Issuance of common stock for director compensation(shares)			45,290
Taxes related to net share settlement of equity awards	(192)			(192)
Conversion of Class B Common Stock, Shares		(1,211,959)	1,211,959
Conversion of Class B Common Stock	0
Stock-based compensation	13,544			13,544
Net Income (Loss)	(123,462)				(123,462)
Balance at Dec. 31, 2023	$ 70,672		$ 5	$ 486,930	$ (416,263)
Balance, shares at Dec. 31, 2023			48,077,599

Stockholders' equity - Summary of Stock Option Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock Options Outstanding, Beginning Balance, Number of Shares	2,736,918	1,086,902
Exercised, Number of Shares	0	0
Forfeiture, Number of Shares	(371,439)	(50,387)
Expired, Number of Shares	(112,367)	(17,797)
Stock Options Outstanding, Ending Balance, Number of Shares	6,273,507	2,736,918	1,086,902
Vested and expected to vest, Number of Shares	6,273,507
Equity Option
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Granted, Number of Shares	4,020,395	1,718,200
Exercisable, Number of Shares	1,429,449
Outstanding, Beginning Balance, Weighted-Average Exercise Price per Share	$ 13.82	$ 26.76
Granted, Weighted-Average Exercise Price per Share	3.74	6.35
Exercised, Weighted average exercise price per option	0	0
Forfeited, Weighted average exercise price per option	7.2	21.64
Expired, Weighted average exercise price per option	20.96	40
Exercisable, Weighted average exercise price per option	14.98
Outstanding, Ending Balance, Weighted-Average Exercise Price per Share \| $ / shares	7.62	$ 13.82	$ 26.76
Vested and expected to vest, Weighted-Average Exercise Price per Share	$ 7.62
Outstanding, Weighted-Average Remaining Contractual Term (years)	8 years 7 months 20 days	8 years 9 months 25 days	9 years 2 months 19 days
Vested and expected to vest, Weighted-Average Remaining Contractual Term (years)	8 years 7 months 20 days
Exercisable, Weighted-Average Remaining Contractual Term (years)	7 years 9 months
Outstanding, Aggregate Intrinsic Value	$ 3,636,148	$ 991,495
Outstanding, Aggregate Intrinsic Value	74,680	$ 3,636,148	$ 991,495
Vested and expected to vest, Aggregate Intrinsic Value	74,680
Exercisable, Aggregate Intrinsic	$ 2,007

Organization and summary of significant accounting policies - Schedule of Earnings Per Share, Basic and Diluted (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Numerator:
Net Income (Loss)	$ (123,462)	$ (106,482)
Denominator:
Weighted-average shares of common stock outstanding, diluted	47,777,568	38,927,268

- Definition

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

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 235
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(g)(1)(ii))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480678/235-10-S99-1

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 323
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481687/323-10-50-3

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 825
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 28
-Subparagraph (f)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482907/825-10-50-28

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 220
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
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-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482765/220-10-50-6

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
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-Name Accounting Standards Codification
-Section 50
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-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483443/250-10-50-3

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
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-Paragraph 1
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Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 815
-SubTopic 40
-Name Accounting Standards Codification
-Section 65
-Paragraph 1
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-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480175/815-40-65-1

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
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Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
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-Section 50
-Paragraph 9
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-URI https://asc.fasb.org//1943274/2147483443/250-10-50-9

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
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-Paragraph 11
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-URI https://asc.fasb.org//1943274/2147483443/250-10-50-11

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
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-URI https://asc.fasb.org//1943274/2147483443/250-10-50-11

Reference 12: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
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-URI https://asc.fasb.org//1943274/2147483443/250-10-50-4

Reference 13: http://www.xbrl.org/2003/role/exampleRef
-Topic 946
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-Name Accounting Standards Codification
-Section 55
-Paragraph 10
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480167/946-830-55-10

Reference 14: http://www.xbrl.org/2003/role/disclosureRef
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+ Details

Pay vs Performance Disclosure - USD ($) $ in Thousands	12 Months Ended
Pay vs Performance Disclosure - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Pay vs Performance Disclosure
Net Income (Loss)	$ (123,462)	$ (106,482)

- Definition

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

+ References

+ Details

Organization and summary of significant accounting policies (Policies)

12 Months Ended

Dec. 31, 2023

Accounting Policies [Abstract]

Organization

Basis of Presentation

Liquidity and going concern

Liquidity and Going Concern

Variable interest entities

Variable Interest Entities (“VIE”)

Use of estimates

Use of Estimates

Segment reporting

Segment Reporting

Cash and cash equivalents

Cash and Cash Equivalents

Concentration of risk

Concentrations of Risk

Property and equipment

Property and Equipment

Impairment of long-lived assets

Impairment of Long-Lived Assets

Leases

Revenue recognition

Revenue Recognition

Research and development expenses

Research and Development Expenses

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

Income taxes

Income Taxes

Comprehensive loss

Comprehensive Loss

Net loss per unit/share

Net Loss Per Share

Potentially dilutive securities not included in the calculation of diluted net loss per common share because to do so would be anti-dilutive are as follows (in common stock equivalents):


	December 31,
	2023		2022
Common stock options		6,273,507		2,736,918
Restricted stock units		99,104		510,039
ESPP Shares		57,253		13,370
Total		6,429,864		3,260,327

Recent accounting pronouncements

Recent Accounting Pronouncements

Document and Entity Information - USD ($) $ in Millions	12 Months Ended
Document and Entity Information - USD ($) $ in Millions	Dec. 31, 2023	Mar. 22, 2024	Jun. 30, 2023
Document Information [Line Items]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2023
Document Fiscal Year Focus	2023
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			$ 91.0
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	Part III incorporates by reference certain information from the registrant’s definitive proxy statement (the “Proxy Statement”) relating to its 2024 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.
Document Financial Statement Error Correction [Flag]	false
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		48,096,717
Common Class B
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		0

Stockholders' equity - Additional Information (Details) - USD ($)		1 Months Ended			12 Months Ended
	Jan. 01, 2021	Jan. 31, 2023	Nov. 30, 2022	Mar. 31, 2022	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Nov. 08, 2022
Class Of Stock [Line Items]
Common stock, shares issued					48,077,599	46,336,166
Preferred stock, shares authorized					200,000,000	200,000,000
Preferred stock, par value					$ 0.0001	$ 0.0001
Common stock, shares authorized					350,000,000	350,000,000
Common stock par value per share		$ 0.0001			$ 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					$ 6,700,000	$ 6,900,000
Share-based payment arrangement, nonvested award, cost not yet recognized, period for recognition					8 months 12 days
Total number of common shares reserved for issuance					8,776,826	7,329,913
Equity Option
Class Of Stock [Line Items]
Share-based payment arrangement, nonvested award, option, cost not yet recognized, amount					$ 15,600,000
Share-based payment arrangement, nonvested award, cost not yet recognized, period for recognition					2 years 9 months 18 days
Share-based compensation arrangement by share based payment award options grants in period weighted average grant date fair value					$ 2.61	$ 4.06
Restricted Stock Units (RSUs)
Class Of Stock [Line Items]
Number of shares, vested					433,948	446,260
Compensation expense on issuance of director compensation					$ 100,000
Share-based payment arrangement, nonvested award, option, cost not yet recognized, amount					$ 1,800
Restricted Stock Units (RSUs) \| Board of Directors
Class Of Stock [Line Items]
Number of shares, vested					45,290
Open Market Sale Agreement
Class Of Stock [Line Items]
Maximum aggregate gross proceeds		$ 100,000,000
Common Stock Warrants
Class Of Stock [Line Items]
Vesting terms, description					The warrants became exercisable upon the Company's IPO for a period of 365 and 450 days
2020 Equity Incentive Plan
Class Of Stock [Line Items]
Common shares authorized for issuance					9,196,970	7,658,509
Shares available for awards, description	4
Vesting percentage					25.00%
Vesting period					36 months
Vesting terms, description					ten years
Compensation cost for the modified unvested restricted stock units					$ 416,000
Number of modified fully vested options					130,699
Increase in compensation cost of fully vested options					$ 123,000
2020 Equity Incentive Plan \| Restricted Stock Units (RSUs)
Class Of Stock [Line Items]
Total number of modified unvested restricted stock units					139,730
Employees Stock Purchase Plan Shares
Class Of Stock [Line Items]
Common stock, shares issued					165,550	147,564
Common stock, shares authorized					1,737,098	1,229,148
Purchase common stock through payroll deductions of up to compensations, percent					15.00%
Share-based compensation arrangement by share based payment award percentage of outstanding stock maximum					1.00%
Increase in common stock authorized for issuance					929,658
Total number of common shares reserved for issuance						1,412,802
Stock-based compensation expense					$ 200,000
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
Class B Common Stock
Class Of Stock [Line Items]
Common stock, shares issued					0	1,211,959
Common stock, shares authorized					15,368,569	15,368,569
Common stock par value per share					$ 0.0001	$ 0.0001
Common Stock
Class Of Stock [Line Items]
Common stock, voting rights					one
Common Stock Options \| 2020 Equity Incentive Plan
Class Of Stock [Line Items]
Total number of modified unvested options					574,244
Compensation cost for the modified unvested options					$ 962,000

Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2023	Dec. 31, 2022
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	48,077,599	46,336,166
Common Stock, Shares, Outstanding	48,077,599	46,336,166
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	0	1,211,959
Common Stock, Shares, Outstanding	0	1,211,959

Stockholders' equity - Schedule of Common Stock Reserved for Future Issuance (Details) - shares	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Class Of Stock [Line Items]
Common Stock, Shares, Issued	48,077,599	46,336,166
Common Stock, Shares, Outstanding	48,077,599	46,336,166
Total number of common shares reserved for issuance	8,776,826	7,329,913
Common Stock Options and Restricted Stock Units [Member]
Class Of Stock [Line Items]
Common Stock, Shares, Issued	6,372,611	3,246,957
Common Stock, Shares, Outstanding	6,372,611	3,246,957
2020 Plan [Member]
Class Of Stock [Line Items]
Awards	991,413	3,012,554
Employees Stock Purchase Plan Shares
Class Of Stock [Line Items]
Common Stock, Shares, Issued	165,550	147,564
Awards	1,412,802	1,070,402
Total number of common shares reserved for issuance		1,412,802

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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+ Details

Consolidated Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Operating expenses:
Research and development expense	$ 103,731	$ 79,347
General and administrative expense	25,956	28,793
Total operating expenses	129,687	108,140
Loss from operations	(129,687)	(108,140)
Other income (expense):
Interest income	6,312	1,648
Other income (expense)	(87)	10
Total other income (expense)	6,225	1,658
Consolidated net loss and comprehensive loss	$ (123,462)	$ (106,482)
Net loss per common share, basic	$ (2.58)	$ (2.74)
Net loss per common share, diluted	$ (2.58)	$ (2.74)
Weighted-average shares of common stock outstanding, basic	47,777,568	38,927,268
Weighted-average shares of common stock outstanding, diluted	47,777,568	38,927,268

Income taxes (Tables)

12 Months Ended

Dec. 31, 2023

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,
	2023			2022
Tax computed at the federal statutory rate	$	(25,927	)	$	(22,361	)
State income taxes, net of federal tax benefit		(8	)		(6	)
Nondeductible executive compensation		99			685
Stock-based compensation		1,326			1,132
Research and development and orphan drug credits		(6,205	)		(3,692	)
Uncertain tax positions		1,551			910
Other, net		228			(23	)
Valuation allowance		28,936			23,355
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,
	2023			2022
Deferred tax assets:
Net operating loss carryforwards	$	25,034		$	17,430
Liability to licensor		4,159			4,159
Goodwill		2,938			3,193
Lease liability		517			836
Accrued compensation		746			659
Research credit carryforwards		10,379			5,760
Section 174 cost capitalization		31,220			14,523
Section 59(e) cost capitalization		8,400			9,450
Stock-based compensation		2,790			1,628
Other		4			3
Gross deferred tax assets		86,187			57,641
Less: valuation allowance		(85,642	)		(56,706	)
Total deferred tax assets		545			935
Deferred tax liabilities:
Fixed assets		(231	)		(426	)
Operating lease right-of-use asset		(314	)		(509	)
Total deferred tax liabilities		(545	)		(935	)
Net deferred tax assets	$	—		$	—

Schedule of Unrecognized Tax Benefits


	Years Ended December 31,
	2023		2022
Unrecognized tax benefits - beginning	$	1,968	$	1,011
Gross increases - tax positions in prior period		161		11
Gross increase – current-period tax positions		1,473		946
Unrecognized tax benefits - ending	$	3,602	$	1,968

Income taxes - Schedule of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Deferred tax assets:
Net operating loss carryforwards	$ 25,034	$ 17,430
Liability to licensor	4,159	4,159
Goodwill	2,938	3,193
Lease liability	517	836
Accrued compensation	746	659
Research credit carryforwards	10,379	5,760
Section 174 cost capitalization	31,220	14,523
Section 59(e) cost capitalization	8,400	9,450
Stock-based compensation	2,790	1,628
Other	4	3
Gross deferred tax assets	86,187	57,641
Less valuation allowance	(85,642)	(56,706)
Total deferred tax assets	545	935
Deferred tax liabilities:
Fixed assets	(231)	(426)
Operating lease right-of-use asset	(314)	(509)
Total deferred tax liabilities	(545)	(935)
Net deferred tax assets	$ 0	$ 0

Stockholders equity (Tables)

12 Months Ended

Dec. 31, 2023

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 statements of operations and comprehensive loss as follows (in thousands):


	Years ended December 31,
	2023		2022
Research and development	$	5,462	$	5,419
General and administrative		8,082		9,144
Total	$	13,544	$	14,563

Summary of Restricted Stock Units

The following table summarizes RSU activity under the 2020 Plan for the years ended December 31, 2023 and 2022:


	Number of Shares			Weighted - average grant date fair value
Outstanding at December 31, 2021		975,046		$	—
Granted		—		$	—
Vested		(446,260	)	$	18.00
Forfeited		(18,747	)
Outstanding at December 31, 2022		510,039		$	18.00
Granted		45,290		$	2.35
Vested		(433,948	)	$	16.37
Forfeited		(22,277	)	$	18.00
Outstanding at December 31, 2023		99,104		$	18.00

Summary of Stock Option Activity

The following table summarizes stock option activity under the 2020 Plan for the year ended December 31, 2023 and 2022 (in thousands, except share and per option data and years):


	Number of options			Weighted - average exercise price per option		Weighted - average remaining contractual term (in years)		Aggregate intrinsic value
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
Granted		4,020,395		$	3.74
Exercised		—		$	—
Forfeited		(371,439	)	$	7.20
Expired		(112,367	)	$	20.96
Balance at December 31, 2023		6,273,507		$	7.62		8.64	$	74,680
Vested and expected to vest at December 31, 2023		6,273,507		$	7.62		8.64	$	74,680
Exercisable at December 31, 2023		1,429,449		$	14.98		7.75	$	2,007

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,
	2023			2022
Expected volatility		77.9	%		74.9	%
Risk-free interest rate		3.89	%		2.14	%
Expected dividend yield		0.0	%		0.0	%
Expected term	6.05 years			6.04 years

Schedule of Common Stock Reserved for Future Issuance

Common stock reserved for future issuance are as follows in common equivalent shares:


	December 31,
	2023		2022
Common stock options and restricted stock units issued and outstanding		6,372,611		3,246,957
Awards available for future issuance under the 2020 Plan		991,413		3,012,554
Awards available for future issuance under the ESPP		1,412,802		1,070,402
Total common stock reserved for future issuance		8,776,826		7,329,913

Stockholders' equity - Summary of Restricted Stock Units (Details) - Restricted Stock Units (RSUs) - $ / shares	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Class Of Stock [Line Items]
Number of Outstanding Shares, Beginning Balance	510,039	975,046
Number of Shares, Granted	45,290	0
Number of Shares, Vested	(433,948)	(446,260)
Number of Shares, forfeited	(22,277)	(18,747)
Number of Outstanding Shares, Ending Balance	99,104	510,039
Weighted Average Grant Date Fair Value, Beginning Balance	$ 18	$ 0
Weighted Average Grant Date Fair Value, Granted	2.35	0
Weighted Average Grant Date Fair Value, Vested	16.37	18
Weighted Average Grant Date Fair Value, Forfeited	18
Weighted Average Grant Date Fair Value, Ending Balance	$ 18	$ 18

Stockholders equity

12 Months Ended

Dec. 31, 2023

Equity [Abstract]

Stockholders equity (deficit)

6. 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.

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 from 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 the Company's 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 the Company's 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 or December 31, 2023.

Open market sale agreement

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.

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, 2023 and 2022, the total number of common shares authorized for issuance under the 2020 Plan was 9,196,970 and 7,658,509, 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.

On February 26, 2023, the Compensation Committee of the Company’s board of directors approved a modification to the Company’s 2020 Plan to allow vesting of RSUs or stock options, as applicable, subject to the grantee’s continued service to the Company and/or one of its subsidiaries as an employee, non-employee director, or independent contractor. Unvested RSUs totaling 139,730 shares and 574,244 unvested options which would have been forfeited under the original terms of the 2020 Plan will now continue to vest. The Company applied modification accounting to these awards which resulted in a decrease in fair value to these awards. The Company calculated compensation cost for the modified unvested awards of $416,000 related to the RSUs and $962,000 related to the options, and will recognize these amounts over the remaining requisite service periods. The modification also resulted in an increase to the term of 130,699 fully vested options for which $123,000 of incremental compensation cost was immediately recognized on the date of the modification.

Stock-based compensation expense recognized for all equity awards under the 2020 Plan has been reported in the statements of operations and comprehensive loss as follows (in thousands):


	Years ended December 31,
	2023		2022
Research and development	$	5,462	$	5,419
General and administrative		8,082		9,144
Total	$	13,544	$	14,563

Restricted stock units

In December 2022, the Company’s board of directors approved an amendment to the Director Compensation Policy, which allows each director to elect to receive their quarterly director fees in the form of restricted stock in lieu of cash. Two board members elected to receive shares of restricted stock in lieu of cash. For the twelve months ended December 31, 2023, the Company issued 45,290 shares of fully vested restricted stock to the two board members. Compensation expense was earned and recognized for these fully vested restricted stock grants in the amount of $0.1 million for the twelve months ended December 31, 2023.

The following table summarizes RSU activity under the 2020 Plan for the years ended December 31, 2023 and 2022:


	Number of Shares			Weighted - average grant date fair value
Outstanding at December 31, 2021		975,046		$	—
Granted		—		$	—
Vested		(446,260	)	$	18.00
Forfeited		(18,747	)
Outstanding at December 31, 2022		510,039		$	18.00
Granted		45,290		$	2.35
Vested		(433,948	)	$	16.37
Forfeited		(22,277	)	$	18.00
Outstanding at December 31, 2023		99,104		$	18.00

As of December 31, 2023, total unrecognized stock-based compensation expense for RSUs was $1.8 million, which is expected to be recognized over a remaining weighted-average period of approximately 0.7 years.

Stock options

The following table summarizes stock option activity under the 2020 Plan for the year ended December 31, 2023 and 2022 (in thousands, except share and per option data and years):


	Number of options			Weighted - average exercise price per option		Weighted - average remaining contractual term (in years)		Aggregate intrinsic value
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
Granted		4,020,395		$	3.74
Exercised		—		$	—
Forfeited		(371,439	)	$	7.20
Expired		(112,367	)	$	20.96
Balance at December 31, 2023		6,273,507		$	7.62		8.64	$	74,680
Vested and expected to vest at December 31, 2023		6,273,507		$	7.62		8.64	$	74,680
Exercisable at December 31, 2023		1,429,449		$	14.98		7.75	$	2,007

As of December 31, 2023, total unrecognized stock-based compensation cost for unvested common stock options was $15.6 million, which is expected to be recognized over a remaining weighted-average period of approximately 2.8 years. The weighted- average grant date fair value of stock options granted during the years ended December 31, 2023 and 2022 was $2.61 per share and $4.06 per share, respectively. The total fair

value of options vested during the years ended December 31, 2023 and 2022 was $6.7 million and $6.9 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,
	2023			2022
Expected volatility		77.9	%		74.9	%
Risk-free interest rate		3.89	%		2.14	%
Expected dividend yield		0.0	%		0.0	%
Expected term	6.05 years			6.04 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, 2023 and 2022, a total of 1,737,098 and 1,229,148 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). During the years ended December 31, 2023 and 2022, the Company issued 165,550 and 147,564 shares of common stock under the ESPP, respectively. As of December 31, 2023, 1,412,802 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, 2023 and 2022 was $0.2 million, respectively.

Common stock reserved for future issuance

Common stock reserved for future issuance are as follows in common equivalent shares:


	December 31,
	2023		2022
Common stock options and restricted stock units issued and outstanding		6,372,611		3,246,957
Awards available for future issuance under the 2020 Plan		991,413		3,012,554
Awards available for future issuance under the ESPP		1,412,802		1,070,402
Total common stock reserved for future issuance		8,776,826		7,329,913

- Definition

The entire disclosure for equity.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
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-Name Accounting Standards Codification
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
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Reference 4: http://www.xbrl.org/2003/role/disclosureRef
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Reference 5: http://www.xbrl.org/2003/role/disclosureRef
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-Subparagraph (d)
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Reference 6: http://www.xbrl.org/2003/role/disclosureRef
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Reference 7: http://www.xbrl.org/2003/role/disclosureRef
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Reference 8: http://www.xbrl.org/2003/role/disclosureRef
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Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 235
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-Name Accounting Standards Codification
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-Paragraph 1
-Subparagraph (SX 210.4-08(e)(1))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480678/235-10-S99-1

Reference 10: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 505
-Name Accounting Standards Codification
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-URI https://asc.fasb.org//505/tableOfContent

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
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Reference 12: http://www.xbrl.org/2003/role/disclosureRef
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Reference 13: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
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-Subparagraph (i)
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-URI https://asc.fasb.org//1943274/2147481112/505-10-50-13

Reference 14: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
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-URI https://asc.fasb.org//1943274/2147481112/505-10-50-14

Reference 15: http://www.xbrl.org/2003/role/disclosureRef
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Reference 16: http://www.xbrl.org/2003/role/disclosureRef
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Reference 17: http://www.xbrl.org/2003/role/disclosureRef
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Reference 18: http://www.xbrl.org/2003/role/disclosureRef
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Reference 19: http://www.xbrl.org/2003/role/disclosureRef
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-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481112/505-10-50-18

+ Details

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

Insider Trading Arrangements	3 Months Ended
Insider Trading Arrangements	Dec. 31, 2023
Trading Arrangements, by Individual
Rule 10b5-1 Arrangement Adopted	false
Non-Rule 10b5-1 Arrangement Adopted	false
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false

Leases - Summary of Weighted Average Remaining Lease Term And Weighted Average Discount Rate (Details)	Dec. 31, 2023	Dec. 31, 2022
Leases [Abstract]
Weighted average remaining lease term (in years)	1 year 6 months	2 years 6 months
Weighted average discount rate percentage	3.50%	3.50%

Leases - Additional Information (Details)	12 Months Ended
Leases - Additional Information (Details)	Dec. 31, 2023
Leases [Abstract]
Lessor Operating Leases Option To Extend	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. Additionally, the lease includes certain rent abatement, rent escalations, tenant improvement allowances and additional charges for common area maintenance and other costs.

Balance sheet details - Schedule of Property and Equipment (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Property And Equipment [Line Items]
Property and equipment, gross	$ 7,681	$ 8,092
Less accumulated depreciation and amortization	(6,078)	(5,364)
Total	1,603	2,728
Furniture Fixtures and Office Equipment
Property And Equipment [Line Items]
Property and equipment, gross	$ 1,721	$ 2,140
Laboratory Equipment
Property And Equipment [Line Items]
Property and equipment useful life	5 years	5 years
Property and equipment, gross	$ 2,280	$ 2,265
Leasehold Improvements
Property And Equipment [Line Items]
Property and equipment, gross	$ 3,680	$ 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

Stockholders' equity - Summary of Assumptions Used in Black-Scholes Model (Details)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Stockholders' Equity Note [Abstract]
Expected volatility	77.90%	74.90%
Risk-free interest rate	3.89%	2.14%
Expected dividend yield	0.00%	0.00%
Expected term	6 years 18 days	6 years 14 days

401(k) plan - Additional Information (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2023 USD ($)
Retirement Benefits [Abstract]
Contributions made by company	$ 0

Fair value measurements - Additional Information (Details) - USD ($)	Dec. 31, 2023	Dec. 31, 2022
Fair Value Disclosures [Abstract]
Assets measured at fair value	$ 0	$ 0
Liability measured at fair value	0	0
Cash and Cash Equivalents	$ 50,400,000	$ 0

Balance sheet details - Schedule of Prepaid Expenses Other Current Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Balance Sheet Related Disclosures [Abstract]
Prepaid research and development	$ 4,615	$ 4,385
Other prepaid expenses and current assets	320	539
Total	$ 4,935	$ 4,924

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, 2023	Dec. 31, 2022
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from calculation of diluted net loss per share	6,429,864	3,260,327
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	6,273,507	2,736,918
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	99,104	510,039
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	57,253	13,370

Subsequent events - Additional Information (Details) - $ / shares	Dec. 31, 2023	Jan. 31, 2023	Dec. 31, 2022
Subsequent Event [Line Items]
Common stock par value per share	$ 0.0001	$ 0.0001	$ 0.0001

Commitments and contingencies	12 Months Ended
Commitments and contingencies	Dec. 31, 2023
Commitments and Contingencies Disclosure [Abstract]
Commitments and contingencies	. 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.

Leases - Maturities of Operating Lease Liabilities (Details) $ in Thousands	Dec. 31, 2023 USD ($)
Leases [Abstract]
2024	$ 1,685
2025	845
Thereafter	0
Total future lease payments	2,530
Less imputed interest	(70)
Total operating lease liabilities	$ 2,460