BioAtla (BCAB) 10-K 28 Feb 22 2021 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($) $ in Billions	12 Months Ended
	Dec. 31, 2021	Feb. 25, 2022	Jun. 30, 2021
Document Information [Line Items]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2021
Document Fiscal Year Focus	2021
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	Large Accelerated Filer
Entity Small Business	false
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			$ 1
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	true
Documents Incorporated by Reference	DOCUMENTS INCORPORATED BY REFERENCE Part III incorporates by reference certain information from the registrant’s definitive proxy statement (the “Proxy Statement”) relating to its 2022 Annual Meeting of Stockholders. The Proxy Statement will be filed with the United States Securities and Exchange Commission within 120 days after the end of the fiscal year to which this report relates.
Auditor Name	Ernst & Young LLP
Auditor Location	San Diego, California
Auditor Firm ID	42
Common Stock
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		35,829,127
Common Class B
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		1,492,059

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 244,979	$ 238,605
Prepaid expenses and other current assets	2,313	2,076
Total current assets	247,292	240,681
Property and equipment, net	3,676	4,102
Operating lease right-of-use-asset, net	3,300	0
Other assets	154	154
Total assets	254,422	244,937
Current liabilities:
Accounts payable and accrued expenses	18,424	12,068
Current portion of deferred rent	0	387
Current portion of deferred revenue	0	19,806
Operating lease liabilities	1,389	0
Total current liabilities	19,813	32,261
Long-term accrued interest	0	5
Deferred rent, less current portion	0	2,015
Operating lease liabilities, less current portion	3,982	0
Liability to licensor	19,806	0
Other debt	0	682
Total liabilities	43,601	34,963
Commitments and contingencies (Note 6)
Stockholders' equity:
Preferred stock, $0.0001 par value; 200,000,000 shares authorized at December 31,2021 and 2020; 0 shares issued and outstanding at December 31, 2021 and 2020	0	0
Additional paid-in capital	397,136	300,888
Accumulated deficit	(186,319)	(90,917)
Total stockholders' equity	210,821	209,974
Total liabilities and stockholders' equity	254,422	244,937
Common Class B
Stockholders' equity:
Common stock value	0	0
Common Stock
Stockholders' equity:
Common stock value	$ 4	$ 3

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2021	Dec. 31, 2020
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	35,799,233	32,171,560
Common Stock, Shares, Outstanding	35,799,233	32,171,560
Common Class B
Common Stock, Par or Stated Value Per Share	$ 0.0001	$ 0.0001
Common Stock, Shares Authorized	15,368,569	15,368,569
Common Stock, Shares, Issued	1,492,059	1,492,059
Common Stock, Shares, Outstanding	1,492,059	1,492,059

Consolidated Statements of Oper

Consolidated Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Collaboration and other revenue		$ 250	$ 429	$ 5,200
Operating expenses:
Research and development expense (includes related party amounts of $0, $0, and $1,885, respectively)		58,274	19,933	25,919
General and administrative expense (includes related party amounts of $0, $0, and $15, respectively)		38,416	10,595	7,549
Total operating expenses		96,690	30,528	33,468
Loss from operations		(96,440)	(30,099)	(28,268)
Other income (expense):
Interest income		350	100	128
Interest expense (includes related party amounts of $0, $147 and $52, respectively)		(3)	(1,389)	(1,630)
Change in fair value of derivative liability		0	(1,581)	(63)
Gain (loss) on extinguishment of long-term debt		690	(2,883)	0
Other income (expense)		1	(1)	(22)
Total other income (expense)		1,038	(5,754)	(1,587)
Consolidated net loss and comprehensive loss		(95,402)	(35,853)	(29,855)
Net loss attributable to noncontrolling interests		0	0	61
Net loss attributable to BioAtla, Inc./BioAtla LLC		$ (95,402)	$ (35,853)	(29,794)
Net loss allocable to Class C preferred unit holders				9,089
Class C preferred return				(8,026)
Net loss attributable to Class A unit holders				$ (28,731)
Net loss per common share, basic and diluted	[1]	$ (2.76)	$ (3.19)
Weighted-average shares of common stock outstanding, basic and diluted	[1]	34,561,245	8,428,153
Class A units
Other income (expense):
Net loss per common share, basic and diluted				$ (0.53)
Weighted-average shares of common stock outstanding, basic and diluted				54,600,000
[1]	The net loss attributable to common stockholders and related per share amounts for the year ended December 31, 2020 are based on the period from July 10, 2020 to December 31, 2020, the period where the Company had outstanding common stock (see Note 1).

Consolidated Statements of Op_2

Consolidated Statements of Operations and Comprehensive Loss (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Research and Development Expense
Research and development expense related party	$ 0	$ 0	$ 1,885
General and Administrative Expense
General and administrative expense related party	0	0	15
Interest Expense
Interest expense, related party	$ 0	$ 147	$ 52

Consolidated Statements of Conv

Consolidated Statements of Convertible Preferred Stock and Stockholders / Members Equity (Deficit) - USD ($) $ in Thousands	Total	Series D Convertible Preferred Stock	Class C Preferred Units	Class A Units	Class B Common Stock	Common Stock	Common StockClass A Units	Additional Paid-in Capital	Retained Earnings	Noncontrolling Interest	Preferred Stock [Member]Class C Preferred Units
Balance at Dec. 31, 2018	$ (28,446)						$ 750		$ (118,560)	$ 19	$ 89,345
Balance, shares at Dec. 31, 2018				54,600,000							23,968,178
Noncontrolling interest	(5)									(5)
Warrants issued by affiliates in connection with modification of convertible promissory notes	764							$ 764
Assumption of unvested profits interest liability by affiliates	197							197
Assumption of vested profits interest liability by affiliates	800							800
Beneficial conversion feature in convertible promissory notes	534							534
Taxes related to net share settlement of equity awards	0
Net loss	(29,855)								(29,794)	(61)
Balance at Dec. 31, 2019	(56,011)						$ 750	2,295	(148,354)	(47)	$ 89,345
Balance, shares at Dec. 31, 2019				54,600,000							23,968,178
Noncontrolling interest	(19)
Issuance of Series D convertible preferred stock for cash, net of $4,317 of issuance costs		$ 68,183
Issuance of Series D convertible preferred stock for cash, net of $4,317 of issuance costs, shares		140,626,711
Issuance of Series D convertible preferred stock in connection with settlement of convertible promissory notes		$ 30,594
Issuance of Series D convertible preferred stock in connection with settlement of convertible promissory notes, shares		59,164,808
Assumption of profits interest liability by affiliate	991							991
Change in profits interest liability of affiliate	749							749
Noncontrolling interest - distribution of net assets to affiliate and related deconsolidation	(19)							(66)		$ 47
LLC Conversion			$ (89,345)	$ (750)		$ 1		(3,196)	93,290
LLC Conversion, shares			(23,968,178)	(54,600,000)
LLC Conversion, common stock						6,220,050
Conversion of Series D convertible preferred stock into common stock	98,777					$ 1		98,776
Convertible preferred stock, Conversion of Series D convertible preferred stock into common stock, shares		(199,791,519)
Convertible preferred stock, Conversion of Series D convertible preferred stock into common stock, value		$ (98,777)
Conversion of Series D convertible preferred stock into common stock, shares					1,492,059	13,876,510
Initial public offering	198,318					$ 1		198,317
Initial public offering, shares						12,075,000
Taxes related to net share settlement of equity awards	0
Stock-based compensation	3,022							3,022
Net loss	(35,853)								(35,853)
Balance at Dec. 31, 2020	209,974					$ 3		300,888	(90,917)
Balance, shares at Dec. 31, 2020					1,492,059	32,171,560
Noncontrolling interest	0
Issuance of common stock under equity incentive plans	0
Issuance of common stock under equity incentive plans, shares						930,144
Issuance of common stock upon exercise of options, net	$ 140							140
Issuance of common stock upon exercise of options, net, shares	7,747					7,747
Issuance of common stock for Employee Stock Purchase Plan	$ 289							289
Issuance of common stock for Employee Stock Purchase Plan, shares						11,182
Initial public offering	70,994					$ 1		70,993
Initial public offering, shares						2,678,600
Taxes related to net share settlement of equity awards	(291)							(291)
Stock-based compensation	25,117							25,117
Net loss	(95,402)								(95,402)
Balance at Dec. 31, 2021	$ 210,821					$ 4		$ 397,136	$ (186,319)
Balance, shares at Dec. 31, 2021					1,492,059	35,799,233

Consolidated Statements of Co_2

Consolidated Statements of Convertible Preferred Stock and Stockholders / Members Equity (Deficit) (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Payments of Stock Issuance Costs	$ 4,007	$ 19,032
Series D Convertible Preferred Stock
Payments of Stock Issuance Costs		$ 4,317

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Cash flows from operating activities
Net loss	$ (95,402)	$ (35,853)	$ (29,855)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	1,330	1,008	860
Loss on disposal of property and equipment	4	0	3
Change in fair value of derivative liability	0	1,581	63
Change in fair value of profits interest liability	0	(6,852)	(6,403)
Loss/(gain) on extinguishment of debt	(690)	2,883	0
Stock-based compensation	25,117	3,022	0
Non-cash interest	0	525	355
Accrued interest	3	864	1,276
Deferred rent	0	(150)	230
Changes in operating assets and liabilities:
Prepaid expenses and other assets	(237)	(1,273)	939
Accounts payable and accrued expenses	7,992	(1,660)	3,218
Accounts payable and accrued expenses—related parties	0	0	(88)
Deferred revenue	0	(429)	19,757
Right-of-use assets and lease liabilities, net	(331)	0	0
Net cash used in operating activities	(62,214)	(36,334)	(9,645)
Cash flows from investing activities
Purchases of property and equipment	(924)	(590)	(1,509)
Net cash used in investing activities	(924)	(590)	(1,509)
Cash flows from financing activities
Noncontrolling interest	0	(19)	(5)
Proceeds from issuance of convertible debt	0	2,750	4,000
Proceeds from issuance of convertible preferred stock, net of issuance costs	0	68,183	0
Proceeds from issuance of PPP loan	0	682	0
Proceeds from initial public offering, net of issuance costs	0	200,229	0
Payment of initial public offering costs	(1,911)	0	0
Proceeds from issuance of common stock	70,994	0	0
Proceeds from exercise of stock options	140	0	0
Proceeds from issuance of common stock under Employee Stock Purchase Plan	289	0	0
Net cash provided by financing activities	69,512	271,825	3,995
Net increase (decrease) in cash and cash equivalents	6,374	234,901	(7,159)
Cash and cash equivalents, beginning of period	238,605	3,704	10,863
Cash and cash equivalents, end of period	244,979	238,605	3,704
Supplemental disclosure of non-cash investing and financing activities
Property and equipment additions included in accounts payable and accrued expenses	1	17	172
Fair value of warrants issued by affiliates in connection with modification of convertible promissory notes	0	0	764
Assumption of profits interest liability by affiliates	0	991	997
Equity issuance costs included in accounts payable and accrued expenses	0	1,911	0
Carrying value of convertible promissory notes settled in connection with Corporate Reorganization	0	27,711	0
Fair value of consideration issued in connection with settlement of convertible promissory notes	0	30,594	0
Tax related to net settlement of equity awards included in accounts payable and accrued expenses	$ 291	$ 0	$ 0

Organization and summary of sig

Organization and summary of significant accounting policies	12 Months Ended
	Dec. 31, 2021
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, after undergoing two separate reorganizations that are further discussed below, was converted to a Delaware corporation in July 2020 and was renamed BioAtla, Inc. (BioAtla, Inc. together with the Pre-Division Predecessor and the Post-Division Successor as defined below, 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. LLC Division In March 2019, BioAtla, LLC (the "Pre-Division Predecessor") was divided into three separate and distinct Delaware limited liability companies (the “Division”) as follows: 1) BioAtla, LLC renamed to BioAtla Holdings, LLC (“BioAtla Holdings”), 2) a new legal entity named Inversagen, LLC (“Inversagen”), and 3) a new legal entity named BioAtla, LLC (the “Post-Division Successor” and together with BioAtla Holdings and Inversagen, the “Post-Division LLCs”). Upon the Division, each Post-Division LLC had substantially the same form of operating agreement and capital structure as the Pre-Division Predecessor, with the following exceptions: i) 1,750,000 Class B units issued by the Post-Division Successor but not by BioAtla Holdings or Inversagen, ii) the outstanding warrants of the Pre-Division Predecessor at the Division date were transferred to the Post-Division Successor (see Note 7), and iii) the Class C units of the Post-Division Successor had liquidation preferences and a preferred return not included in the operating agreements of BioAtla Holdings and Inversagen. In connection with the Division, the Pre-Division Predecessor’s holdings of EXUMA Biotech Corp. (“EXUMA”, formerly F1 Oncology, Inc.) common and preferred stock (see Note 12) remained in BioAtla Holdings and certain rights related to the application of CAB technology in senescent cell therapy were transferred to the Post-Division Successor and simultaneously licensed to Inversagen (see Note 10). The remaining assets and liabilities (including ownership of Himalaya Therapeutics SEZC, or "HTKY", and its wholly-owned subsidiary, Himalaya Therapeutics HK Limited as described below in “Principles of consolidation and deconsolidation”), and substantially all of the operations of the Pre-Division Predecessor, including all existing employees, were transferred to the Post-Division Successor. Each of the Pre-Division Predecessor’s members at the time of the Division continued as a member in the Post-Division Successor, BioAtla Holdings and Inversagen, and each entity has Dr. Jay Short and his spouse, Carolyn Anderson Short, as its LLC managers. There are no shared services agreements between the Company and BioAtla Holdings or Inversagen. The Company has determined that Inversagen is a variable interest entity (“VIE”), the Company is not the primary beneficiary of Inversagen, and that the Post-Division LLCs are under the common control of Jay and Carolyn Short. The Company does not consolidate either BioAtla Holdings or Inversagen (see Note 10). In addition, the Company has no direct equity investment in either BioAtla Holdings or Inversagen that require either equity method or cost method accounting. The assets, liabilities, and employees transferred to the Post-Division Successor in the Division met the definition of a business and the transfer qualifies as a change in reporting entity under Accounting Standards Codification (“ASC”) 250-10-45-21. As such, the historical financial statements of the Pre-Division Predecessor are deemed to be those of the Post-Division Successor, even for periods prior to its formation. As a transfer of a business to an entity under common control, the assets and liabilities of the Pre-Division Predecessor were transferred to the Post-Division Successor at historical carrying values. At the Division date, the Pre-Division Predecessor’s investment in EXUMA and the assets licensed to Inversagen had a zero carrying value and neither EXUMA nor Inversagen had material operations. As such, the Pre-Division historical financial statements presented herein are the historical financial statements of the Pre-Division Predecessor without adjustment. In connection with the Division, certain modifications were made to then outstanding debt agreements and units, including: i) the participation threshold of each Class B unit in each Post-Division LLC was adjusted for the impact of the Division (see Note 8), ii) the amendment of the Pfizer Note and 2018 Notes (as defined and described in Note 4), and iii) the issuance, to both Pfizer and the holders of the 2018 Notes, of conditional warrants by BioAtla Holdings and Inversagen which become exercisable upon the conversion of the Pfizer Note and 2018 Notes into capital stock of the Post-Division Successor (see Note 4). The Post-Division Successor converted to a Delaware corporation in July 2020 as part of the Corporate Reorganization defined and described below, and was renamed BioAtla, Inc. BioAtla, Inc. is the final successor to the Pre-Division Predecessor and the Post-Division Successor, and collectively these entities are referred to as “the Company.” The historical financial statements of the Company prior to the Corporate Reorganization are those of the Pre-Division Predecessor and the Post-Division Successor without adjustment. Corporate Reorganization and Series D Financing In July 2020, BioAtla, LLC (the Post-Division Successor) completed a series of transactions (the “Corporate Reorganization”) in connection with the conversion from a limited liability company into a Delaware corporation, the spin-off of Himalaya Therapeutics SEZC, and the completion of a Series D convertible preferred stock financing. The Corporate Reorganization involved the formation of Himalaya Parent LLC as a wholly owned subsidiary of BioAtla, LLC and the formation of BioAtla MergerSub LLC, as a wholly owned subsidiary of Himalaya Parent LLC. Under the Agreement and Plan of Merger (the “Merger Agreement”), BioAtla, LLC was merged into and with BioAtla MergerSub LLC, with BioAtla, LLC surviving, and the members of BioAtla, LLC immediately prior to the effective time of the Merger Agreement received membership interests, on a one-for-one basis, of Himalaya Parent LLC as consideration, and the then-outstanding warrants to purchase equity of BioAtla, LLC were converted into warrants to purchase common shares of common stock of BioAtla, Inc. (see Note 7). The Himalaya Parent LLC operating agreement provided identical equity rights for the then outstanding units of BioAtla, LLC. In addition: (i) the membership interests of BioAtla, LLC held by Himalaya Parent LLC were exchanged for 6,220,050 shares of BioAtla, Inc. common stock, (ii) BioAtla, Inc. issued an aggregate of 59,164,808 shares of Series D convertible preferred stock to Himalaya Parent LLC and Himalaya Parent LLC issued an aggregate of 59,164,808 Class D units to the holders of convertible notes of BioAtla, LLC in connection with the conversion of their convertible notes into Class D units of Himalaya Parent LLC (see Note 4), (iii) BioAtla, LLC distributed to Himalaya Parent LLC its equity interests in Himalaya Therapeutics SEZC, a then majority-owned subsidiary which is engaged in the development of a set of antibodies in the field of oncology primarily in Greater China, (iv) Himalaya Parent LLC assumed the profits interest liability of BioAtla, LLC (see Note 8) and (v) BioAtla, LLC converted into a Delaware corporation pursuant to a statutory conversion and changed its name to BioAtla, Inc. Following the Corporate Reorganization, Himalaya Parent LLC owned 59,164,808 shares of BioAtla, Inc. Series D convertible preferred stock and 6,220,050 shares of BioAtla, Inc. common stock, all of which were subsequently distributed ("the Distribution") to the members of Himalaya Parent, LLC. As a result of the sale of 140,626,711 shares of Series D convertible preferred stock to new investors in July 2020 (see Note 7), BioAtla, Inc. was not controlled by Himalaya Parent LLC and BioAtla, Inc. does not control Himalaya Parent LLC subsequent to the distribution discussed in item (iii) above (see further discussion in “Principles of consolidation and deconsolidation” below). All pre-Corporate Reorganization operations, employees, property, assets and obligations of BioAtla, LLC (exclusive of the profits interest liability and Himalaya Therapeutics SEZC now held by Himalaya Parent LLC) are held by BioAtla, Inc. Shares of Series D convertible preferred stock were subsequently converted into common stock as part of the Company’s initial public offering (“IPO”) in December 2020. Reverse Stock Split On December 2, 2020, the Company effected a 1-for-13 reverse stock split of its common stock. The par value and the authorized shares of the common stock were not adjusted as a result of the reverse stock split. The reverse stock split resulted in an adjustment to the convertible preferred stock conversion price to reflect a proportional decrease in the number of shares of common stock to be issued upon conversion. The accompanying financial statements and notes to the financial statements give retroactive effect to the reverse stock split. No adjustments have been made to any period for the units outstanding prior to the LLC Conversion. Principles of Consolidation and Deconsolidation Prior to the Corporate Reorganization in July 2020, the consolidated financial statements included the accounts of BioAtla, LLC and those of its majority owned subsidiary Himalaya Therapeutics SEZC that had no material operations. Himalaya Therapeutics SEZC also had a wholly owned subsidiary, Himalaya Therapeutics HK Limited that had no material operations. All intercompany balances were eliminated in consolidation. In connection with the Corporate Reorganization, Himalaya Therapeutics SEZC and Himalaya Therapeutics HK Limited were deconsolidated without material impact to the consolidated financial statements. Subsequent to the Corporate Reorganization and subsequent to the Distribution as defined and described above, Himalaya Parent LLC does not control, is not under common control with, and is not consolidated by BioAtla, Inc. and BioAtla, Inc. is a single legal entity with no consolidated variable interest entities ("VIEs") or subsidiaries (see Note 10). 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, 2021, the Company had an accumulated deficit of $ 186.3 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. Management is required to perform a two-step analysis of the Company’s ability to continue as a going concern. Management must first evaluate whether there are conditions and events that raise substantial doubt about the Company’s ability to continue as a going concern (Step 1). If management concludes that substantial doubt is raised, management is also required to consider whether its plans alleviate that doubt (Step 2). Management’s assessment included the preparation of cash flow forecasts resulting in management’s conclusion that there is not substantial doubt about the Company’s ability to continue as a going concern for 12 months after the date the consolidated financial statements for the year ended December 31, 2021 are issued. Variable Interest Entities The Company consolidates entities in which it has a controlling financial interest. The Company determines whether it has a controlling financial interest in an entity by first evaluating whether the entity is a voting interest entity or a variable interest entity (“VIE”). VIEs are entities in which (i) the total equity investment at risk is sufficient to enable the entity to finance its activities independently, (ii) the equity holders have the power to direct the activities of the entity that most significantly impact its economic performance, the obligation to absorb the losses of the entity and the right to receive the residual returns of the entity and (iii) the legal entity is structured with substantive voting rights. A VIE is an entity that lacks one or more of the characteristics of a voting interest entity. The Company has a controlling financial interest in a VIE when the Company has a variable interest or interests that provide it with (i) the power to direct the activities of the VIE that most significantly impact the VIE’s economic performance and (ii) the obligation to absorb losses of the VIE or the right to receive benefits from the VIE that could potentially be significant to the VIE. The Company evaluates its relationships with its VIEs on an ongoing basis to determine whether or not it has a controlling financial interest (see Notes 10 and 12). Use of Estimates The Company’s consolidated financial statements are prepared in accordance with U.S. generally accepted accounting principles (“GAAP”). The preparation of the Company’s consolidated financial statements requires it to make estimates and assumptions that impact the reported amounts of assets, liabilities, revenues and expenses and the disclosure of contingent assets and liabilities in the Company’s consolidated financial statements and accompanying notes. The most significant estimates in the Company’s consolidated financial statements relate to revenue recognition, accruals for research and development costs, equity-based compensation and fair value measurements. These estimates and assumptions are based on current facts, historical experience and various other factors believed to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities and the recording of revenue and expenses that are not readily apparent from other sources. Actual results may differ materially and adversely from these estimates. To the extent there are material differences between the estimates and actual results, the Company’s future results of operations will be affected. Segment Reporting Operating segments are identified as components of an enterprise about which separate discrete financial information is available for evaluation by the chief operating decision-maker in making decisions regarding resource allocation and assessing performance. The Company views its operations and manages its business in one operating segment. Cash and Cash Equivalents The Company considers all highly liquid investments with original maturities of three months or less when purchased to be cash equivalents. Concentrations of Risk Financial instruments that potentially subject the Company to a significant concentration of credit risk consist primarily of cash and cash equivalents. The Company maintains deposits in federally insured financial institutions in excess of federally insured limits. The Company has not experienced any losses in such accounts and management believes that the Company is not exposed to significant credit risk due to the financial position of the depository institutions in which those deposits are held. For the years ended December 31, 2021, 2020, and 2019 , BeiGene, as defined and described in Note 9, represented 0 %, 100 % and 91 %, respectively, of total revenues. Property and Equipment Property and equipment are stated at cost and depreciated on a straight-line basis over the estimated useful life of the related assets. Leasehold improvements are stated at cost and amortized on a straight-line basis over the lesser of the remaining term of the related lease or the estimated useful life of the leasehold improvements. Repairs and maintenance costs are charged to expense as incurred and expenditures that materially extend the useful lives of assets are capitalized. Impairment of Long-Lived Assets The Company reviews long-lived assets, such as property and equipment, for impairment whenever events or changes in circumstances indicate the carrying amount of an asset may not be recoverable. Recoverability of assets to be held and used is measured by a comparison of the carrying amount of an asset to the future undiscounted net cash flows expected to be generated by the asset. If such assets are considered to be impaired, the impairment to be recognized is measured as the amount by which the carrying amount of the assets exceeds the fair value of the assets. Fair value would be assessed using discounted cash flows or other appropriate measures of fair value. The Company has no t recognized any impairment losses for the years ended December 31, 2021, 2020, and 2019 . Leases The Company adopted the Accounting Standard Update (“ASU”) 2016-02, Leases, and additional ASUs issued to clarify and update the guidance in ASU 2016-02 (collectively, “ASC 842”), as of January 1, 2021. See the section Recently Adopted Accounting Pronouncements below for more information. 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. The Company elected to use the transition relief package of practical expedients but did not elect to use the hindsight practical expedient in determining a lease term and impairment of ROU assets at the adoption date. For short-term leases, defined as leases with a term of twelve months or less, the Company elected the practical expedient to not recognize an associated lease liability and ROU asset. Lease payments for short-term leases are expensed on a straight-line basis over the lease term. The Company does not currently have any short-term leases. Operating leases are included in operating lease right-of-use assets, operating lease liabilities, and operating lease liabilities, non-current on the Company’s consolidated balance sheets. The Company does not have any finance leases. Lease Accounting Prior to the Adoption of ASC 842 For operating leases, the Company recorded rent expense using the straight-line method over the lease term, which includes the period of time from when the Company takes possession of the leased space until leasehold improvements are completed and the space is occupied. The difference between rent expense and amounts paid under the lease agreement is deferred in the accompanying consolidated balance sheets. Tenant improvement allowances and other lease incentives are recorded as liabilities and are amortized on the straight-line basis over the lease term as reductions to rent expense. Beneficial Conversion Features A beneficial conversion feature is a non-detachable conversion feature that is “in the money” at the commitment date, which requires recognition of interest expense for underlying debt instruments and a deemed dividend for underlying equity instruments. A conversion option is “in the money” if the effective conversion price is lower than the commitment date fair value of the share into which it is convertible. Accounting for Derivatives The Company evaluates its convertible instruments and other contracts to determine if those contracts or embedded components of those contracts are required to be recognized under Accounting Standards Codification (“ASC”) Topic 815, Derivatives and Hedging . The result of this accounting treatment is that the derivative is carried at fair value as an asset or liability with changes in fair value recognized in earnings as they occur. Although separately measured at fair value, the fair value of bifurcated embedded derivatives is presented with the host contract in the consolidated balance sheets. Changes in the fair value of derivatives are recorded in the accompanying consolidated statements of operations and comprehensive loss as a component of other income (expense). Revenue Recognition The Company recognizes revenue in a manner that depicts the transfer of control of a product or a service to a customer and reflects the amount of the consideration the Company is entitled to receive in exchange for such product or service. In doing so, the Company follows a five-step approach: (i) identify the contract with a customer, (ii) identify the performance obligations in the contract, (iii) determine the transaction price, (iv) allocate the transaction price to the performance obligations, and (v) recognize revenue when (or as) the customer obtains control of the product or service. The Company considers the terms of a contract and all relevant facts and circumstances when applying the revenue recognition standard. A customer is a party that has entered into a contract with the Company, where the purpose of the contract is to obtain a product or a service that is an output of the Company’s ordinary activities in exchange for consideration. To be considered a contract, (i) the contract must be approved (in writing, orally, or in accordance with other customary business practices), (ii) each party’s rights regarding the product or the service to be transferred can be identified, (iii) the payment terms for the product or the service to be transferred can be identified, (iv) the contract must have commercial substance (that is, the risk, timing or amount of future cash flows is expected to change as a result of the contract), and (v) it is probable that the Company will collect substantially all of the consideration to which it is entitled to receive in exchange for the transfer of the product or the service. A performance obligation is defined as a promise to transfer a product or a service to a customer. The Company identifies each promise to transfer a product or a service (or a bundle of products or services, or a series of products and services that are substantially the same and have the same pattern of transfer) that is distinct. A product or a service is distinct if both (i) the customer can benefit from the product or the service either on its own or together with other resources that are readily available to the customer and (ii) the Company’s promise to transfer the product or the service to the customer is separately identifiable from other promises in the contract. Each distinct promise to transfer a product or a service is a unit of accounting for revenue recognition. If a promise to transfer a product or a service is not separately identifiable from other promises in the contract, such promises should be combined into a single performance obligation. The transaction price is the amount of consideration the Company is entitled to receive in exchange for the transfer of control of a product or a service to a customer. To determine the transaction price, the Company considers the existence of any significant financing component, the effects of any variable elements, noncash consideration and consideration payable to the customer. If a significant financing component exists, the transaction price is adjusted for the time value of money. If an element of variability exists, the Company must estimate the consideration it expects to receive and uses that amount as the basis for recognizing revenue as the product or the service is transferred to the customer. There are two methods for determining the amount of variable consideration: (i) the expected value method, which is the sum of probability-weighted amounts in a range of possible consideration amounts, and (ii) the mostly likely amount method, which identifies the single most likely amount in a range of possible consideration amounts. If a contract has multiple performance obligations, the Company allocates the transaction price to each distinct performance obligation in an amount that reflects the consideration the Company is entitled to receive in exchange for satisfying each distinct performance obligation. For each distinct performance obligation, revenue is recognized when the Company transfers control of the product or the service applicable to such performance obligation. In those instances where the Company first receives consideration in advance of satisfying its performance obligation, the Company classifies such consideration as deferred revenue until (or as) the Company satisfies such performance obligation. In those instances where the Company first satisfies its performance obligation prior to its receipt of consideration, the consideration is recorded as accounts receivable. The Company expenses incremental costs of obtaining and fulfilling a contract as incurred if the expected amortization period of the asset that would be recognized is one year or less, or if the amount of the asset is immaterial. Otherwise, such costs are capitalized as contract assets if they are incremental to the contract and amortized to expense proportionate to revenue recognition of the underlying contract. Research and Development Expenses The Company’s activities have largely consisted of research and development efforts related to developing our CAB programs. Research and development expenses consist of expenses incurred in performing research and development activities including salaries and benefits, facilities and other overhead expenses, clinical trials, contract services and other outside expenses. Research and development expenses are charged to expense as incurred. Payments for these activities are based on the terms of the individual agreements, which may differ from the pattern of costs incurred, and are reflected in the accompanying consolidated balance sheets as prepaid or accrued expenses. When evaluating the adequacy of the accrued expenses, the Company analyzes progress of the services, including the phase or completion of events, invoices received and contracted costs. Significant judgments and estimates may be made in determining the accrued balances at the end of any reporting period. Actual results could differ from the Company’s estimates. As of December 31, 2021, the Company has accrued $ 6.2 million related to clinical trial costs. The Company has entered into contracts related to its clinical trials with clinical research organizations. The Company reviews and accrues clinical trial costs based on work performed, which relies on estimates of total trial management costs, sites activated, patients enrolled, and number of patient visits. The Company follows this method since reasonably dependable estimates of the costs applicable to clinical trials can be made. Accrued clinical trial costs are subject to revisions as the trials progress. Revisions are charged to expense in the period in which the facts that give rise to the revision become known. Historically, revisions have not resulted in material changes to research and development expense; however, a modification in the protocol of a clinical trial or cancellation of a trial could result in a change to the Company's results of operations. Patent Costs Costs related to filing and pursuing patent applications are recorded as general and administrative expenses and expensed as incurred since recoverability of such expenditures is uncertain. Equity-Based Compensation Related to Profits Interest Plan Prior to the Corporate Reorganization in July 2020, the Company had a profits interest plan that was a liability award plan in accordance with ASC Topic 718, Compensation – Stock Compensation (Topic 718) . The Company measured the fair value of each award on the grant date and recognized such fair value over the requisite service period (usually the vesting period) on a straight-line basis. The fair value of the award was remeasured at each reporting date until the award was settled, with a true-up of compensation cost for changes in fair value prorated for the portion of the requisite service period rendered. Once vested, any subsequent change in fair value was recognized immediately. The fair value of any awards that expired or were forfeited or canceled for no value was adjusted to zero, as they occurred, such that any previously recorded compensation cost would be fully reversed. Subsequent to the Corporate Reorganization and amendment of the profits interest plan by Himalaya Parent in October 2020, the Company no longer reflects compensation cost and a corresponding capital contribution associated with the ongoing mark-to-market of the Class B profits interests held by Himalaya Parent LLC. Stock-Based Compensation Stock-based compensation expense represents the grant date fair value of equity awards, consisting of stock options, restricted stock units (“RSUs”) and employee stock purchase plan rights, over the requisite service period of the awards (usually the vesting period) on a straight-line basis. The Company estimates the fair value of stock option grants and employee stock purchase plan rights using the Black-Scholes option pricing model. Prior to the Company’s IPO, the fair value of RSUs was based on the estimated fair value of the underlying common stock on the date of grant and, subsequent to the Company’s IPO, the fair value is based on the closing sales price of the Company’s common stock on the date of grant. Equity award forfeitures are recognized as they occur. Income Taxes The Company accounts for income taxes under the asset and liability method, which requires the recognition of deferred tax assets and liabilities for the expected future tax consequences of events that have been included in the consolidated financial statements. Under this method, deferred tax assets and liabilities are determined based on the differences between the financial statements and tax basis of assets and liabilities using enacted tax rates in effect for the year in which the differences are expected to reverse. The effect of a change in tax rates on deferred tax assets and liabilities is recognized as income in the period that includes the enactment date. The Company recognizes net deferred tax assets to the extent that the Company believes these assets are more likely than not to be realized. In making such a determination, management considers all available positive and negative evidence, including future reversals of existing taxable temporary differences, projected future taxable income, exclusive of reversing temporary difference, tax-planning strategies, and the results of recent operations. If management determines that the Company would be able to realize its deferred tax assets in the future in excess of their net recorded amount, management would make an adjustment to the deferred tax asset valuation allowance, which would reduce the provision for income tax

Balance sheet details

Balance sheet details	12 Months Ended
	Dec. 31, 2021
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, 2021 2020 Prepaid research and development $ 1,811 $ 2,004 Other prepaid expenses and current assets 502 72 Total $ 2,313 $ 2,076 Property and equipment consist of the following (in thousands): December 31, Useful life (years) 2021 2020 Furniture, fixtures and office equipment 3 - 7 $ 2,123 $ 1,719 Laboratory equipment 5 2,123 1,790 Leasehold improvements 2 - 3 3,687 3,663 7,933 7,172 Less accumulated depreciation and amortization ( 4,257 ) ( 3,070 ) Total $ 3,676 $ 4,102 Accounts payable and accrued expenses consist of the following (in thousands): December 31, 2021 2020 Accounts payable $ 1,179 $ 2,456 Accrued compensation 2,671 2,804 Accrued research and development 13,501 4,852 Accrued equity issuance costs — 1,143 Other accrued expenses 1,073 813 Total $ 18,424 $ 12,068

Fair value measurements

Fair value measurements	12 Months Ended
	Dec. 31, 2021
Fair Value Disclosures [Abstract]
Fair value measurements	3. Fair value measurements The carrying amounts of the Company’s current financial assets and current financial liabilities are considered to be representative of their respective fair values because of the short-term nature of those instruments. As of December 31, 2021 and December 31, 2020 , the Company had no financial assets or liabilities measured at fair value on a recurring basis. The accounting guidance defines fair value, establishes a consistent framework for measuring fair value and expands disclosure for each major asset and liability category measured at fair value on either a recurring or non-recurring basis. Fair value is defined as an exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. As such, fair value is a market-based measurement that should be determined based on assumptions that market participants would use in pricing an asset or liability. As a basis for considering such assumptions, the accounting guidance establishes a three-tier fair value hierarchy, which prioritizes the inputs used in measuring fair value as follows: Level 1: Observable inputs such as quoted prices in active markets. Level 2: Inputs, other than the quoted prices in active markets that are observable either directly or indirectly. Level 3: Unobservable inputs in which there is little or no market data, which require the reporting entity to develop its own assumptions. None of the Company’s non-financial assets and liabilities are recorded at fair value on a non-recurring basis. No transfers between levels have occurred during the periods presented. The 2018 Notes (as amended in 2020), the 2019 Notes and the 2020 Notes (each as defined and described in Note 4) contained a redemption feature which was determined to be an embedded derivative requiring bifurcation and separate accounting. The fair value of the derivative was determined based on an income approach that identified the cash flows using a “with-and-without” valuation methodology. The inputs used to determine the estimated fair value of the derivative instrument were based primarily on the probability of an underlying event triggering the embedded derivative occurring and the timing of such event. The following table provides a reconciliation of the embedded derivative liability measured at fair value using Level 3 unobservable inputs (in thousands): Embedded Balance at December 31, 2019 $ 1,856 Initial fair value of embedded derivatives issued 3,415 Change in fair value 1,581 Settlement ( 6,852 ) Balance at December 31, 2020 $ —

Convertible and other debt

Convertible and other debt	12 Months Ended
	Dec. 31, 2021
Debt Disclosure [Abstract]
Convertible and other debt	4. Convertible and other debt Pfizer convertible promissory note In December 2015, the Company issued a $ 10.0 million unsecured convertible promissory note (“Pfizer Note”) to certain affiliates of Pfizer, Inc. (“Pfizer”). The Pfizer Note accrued interest at 8.0 % per annum with a maturity date in December 2020. Prior to amendment in March 2019 as described below, the Pfizer Note, including accrued interest, was convertible at the election of the holder into Class C preferred units at a price of $ 3.394142 per unit and was automatically convertible into i) common shares upon the completion of an IPO based on the price per share paid by investors in the IPO or ii) qualified financing shares upon the completion of a qualified financing based on the price per share paid by investors in the qualified financing. The Company assessed the terms of the Pfizer Note and concluded that it was not share-settled debt, did not contain any embedded derivative features requiring bifurcation and did not contain a beneficial conversion feature. As a result, the Pfizer Note was carried at cost since the Company did not incur a material amount of issuance costs in connection with the debt. The Pfizer Note was amended in March 2019 in connection with the Division to provide the lender additional accrued interest upon conversion. The amended conversion amount of the Pfizer Note was equal to the greater of a) the then outstanding principal plus accrued interest, or b) principal plus accrued interest through December 7, 2020. In connection with the March 2019 amendment, Pfizer received conditional warrants in BioAtla Holdings and Inversagen which allowed Pfizer to acquire an equity interest in each of BioAtla Holdings and Inversagen upon conversion of the Pfizer Note of the Post-Division Successor. The amendment of the Pfizer Note was accounted for as a modification, which required prospective consideration of the revised terms. The Company recognized the initial fair value of the warrants of $ 0.5 million as a fee paid by the Company to the lenders, which was recorded as debt discount on the modified debt and as a capital contribution, as the warrants were written on two entities under common control that were not consolidated with the Company. The debt discount was amortized to interest expense using the effective interest method over the term of the Pfizer Note. The fair value of the conditional warrants was determined using the Option Pricing Method based on the underlying value of the assets allocated to BioAtla Holdings and Inversagen . The Company incurred interest expense in connection with the Pfizer Note of $ 0.6 million and $ 1.0 million for the years ended December 31, 2020 and 2019. As further described below, the Pfizer Note was amended and settled in connection with the Corporate Reorganization in July 2020. 2018 convertible promissory notes In August 2018, the Company issued unsecured convertible promissory notes for an aggregate of $ 5.0 million (the “2018 Notes”). The 2018 Notes accrued interest at 8.0 % per annum with a maturity date in July 2023. Prior to amendment in March 2019, as described below, the then outstanding principal plus accrued interest under the 2018 Notes was convertible at the election of the holder into Class C preferred units at a price of $ 3.394142 per unit and was automatically convertible into i) common shares upon the completion of an IPO based on the price per share paid by investors in the IPO or ii) qualified financing shares upon the completion of a qualified financing based on the price per share paid by investors in the qualified financing. The Company assessed the terms of the 2018 Notes and concluded that they were not share-settled debt, did not contain any embedded derivative features requiring bifurcation and did not contain a beneficial conversion feature. As a result, the 2018 Notes were carried at cost since the Company did not incur a material amount of issuance costs in connection with the issuance of the promissory notes. The 2018 Notes were amended in March 2019 in connection with the Division to provide the lenders additional accrued interest upon conversion. The amended conversion amount of the 2018 Notes was equal to the greater of a) the then outstanding principal plus accrued interest, or b) principal plus accrued interest through December 7, 2020. In connection with the March 2019 amendment, the lenders received conditional warrants in BioAtla Holdings and Inversagen which allowed them to acquire an equity interest in each of BioAtla Holdings and Inversagen upon conversion of the 2018 Notes of the Post-Division Successor. The amendment of the 2018 Notes was accounted for as a modification, which required prospective consideration of the revised terms. The Company recognized the initial fair value of the warrants of $ 0.2 million as a fee paid by the Company to the lenders, which was recorded as debt discount on the modified debt and as a capital contribution, as the warrants were written on two entities under common control that were not consolidated with the Company. The debt discount was amortized to interest expense using the effective interest method over the term of the 2018 Notes. The fair value of the conditional warrants was determined using the Option Pricing Method based on the underlying value of the assets allocated to BioAtla Holdings. The underlying value of the assets allocated to Inversagen was immaterial. The 2018 Notes were amended in April 2020 to add a discount to the conversion prices such that they were convertible (i) automatically into preferred stock upon a qualified equity financing, with a conversion price of 80% of the lowest purchase price per share of preferred stock paid by investors in such qualified equity financing, (ii) automatically convert into common stock upon an initial public offering, with a conversion price of 80% of the price per share of common stock paid by investors in such initial public offering, and (iii) upon the election of each note holder, into Class C preferred units, with a conversion price per share of $ 2.7153136 . The Company concluded that the amendment was an extinguishment and the fair value of the amended 2018 Notes was equal to the then outstanding principal and accrued interest of the 2018 Notes. As a result, the Company recognized a loss on extinguishment for the $ 0.2 million of unamortized discounts at the extinguishment date. In addition, the Company assessed the terms and concluded the amended 2018 Notes: (i) were not share-settled debt, (ii) contained a redemption feature that was determined to be an embedded derivative requiring bifurcation and (iii) did not contain a beneficial conversion feature. The $ 2.2 million issuance date fair value of the embedded derivative liability was recorded as a debt discount and amortized to interest expense using the effective interest method over the remaining term of the 2018 Notes. The Company incurred interest expense, including coupon interest and amortization of debt discounts, in connection with the 2018 Notes of $ 0.4 million and $ 0.4 million for the years ended December 31, 2020 and 2019, respectively. As further described below, the 2018 Notes were amended and settled in connection with the Corporate Reorganization in July 2020. 2019 convertible promissory notes Between August and December 2019, the Company issued unsecured convertible promissory notes payable to various entities in an aggregate principal amount of $ 4.0 million (the “2019 Notes”), of which $ 1.5 million was to related parties. The 2019 Notes accrued interest at 8.0 % per annum with maturity dates of five years after issuance. The outstanding principal amount and any accrued and unpaid interest on the 2019 Notes was due and payable on the earlier to occur of (i) the maturity date, (ii) an event of default, or (iii) immediately prior to an acquisition event. The 2019 Notes were convertible (i) automatically into preferred stock upon a qualified equity financing, with a conversion price of 80% of the lowest purchase price per share of preferred stock paid by investors in such qualified equity financing, (ii) automatically into common stock upon an initial public offering, with a conversion price of 80% of the price per share of common stock paid by investors in such initial public offering, and (iii) upon the election of each note holder, into Class C preferred units, with a conversion price per share of $ 2.7153136 . The number of shares or units issuable upon conversion is determined by dividing the conversion amount by the conversion price, with the conversion amount equal to the greater of a) the then outstanding principal plus accrued interest, or b) principal plus accrued interest through December 7, 2020. The Company assessed the terms and concluded the 2019 Notes: (i) were not share-settled debt, (ii) contained a redemption feature that was determined to be an embedded derivative requiring bifurcation and (iii) certain of the notes contained a beneficial conversion feature because the fair value of the securities into which the 2019 Notes were convertible at the time of issuance, the Class C preferred units, was greater than the effective conversion price of the 2019 Notes. The $ 0.5 million beneficial conversion feature was recorded as additional paid-in capital and a debt discount and the $ 1.8 million issuance date fair value of the embedded derivative liability was recorded as a debt discount, both of which discounts were amortized to interest expense using the effective interest method over the term of the 2019 Notes. In April and May of 2020 certain of the 2019 Notes, representing $ 2.5 million of the then outstanding principal balance, were amended such that the conversion shares or units issuable upon conversion is the greater of: (i) the then outstanding principal plus accrued interest divided by $ 0.86866 or (ii) the amount determined by dividing the conversion amount by the conversion price, with the conversion amount equal to the greater of a) the then outstanding principal plus accrued interest, or b) principal plus accrued interest through December 7, 2020. The amendment of the 2019 Notes was accounted for as a modification, which required prospective consideration of the revised terms. For the year ended December 31, 2020 and 2019, the Company recognized interest expense, including coupon interest and amortization of debt discounts, in connection with the 2019 Notes of $ 0.3 million and $ 0.1 million, respectively. As further described below, the 2019 Notes were amended and settled in connection with the Corporate Reorganization in July 2020. 2020 convertible promissory notes During March, April and May of 2020 the Company issued unsecured convertible promissory notes (the “2020 Notes”) payable to various entities in an aggregate principal amount of $ 2.8 million, of which $ 0.5 million was to related parties. The 2020 Notes accrued interest at 8.0 % per annum with maturity dates of five years after issuance. The Company assessed the terms and concluded the 2020 Notes: (i) were not share-settled debt,(ii) contained a redemption feature that was determined to be an embedded derivative requiring bifurcation and (iii) did not contain a beneficial conversion feature. The $ 1.2 million issuance date fair value of the embedded derivative liability was recorded as a debt discount which was amortized to interest expense using the effective interest method over the term of the 2020 Notes. In May of 2020 certain of the 2020 Notes, representing $ 0.1 million of the then outstanding principal balance, were amended such that the conversion shares or units issuable upon conversion is the greater of: (i) the then outstanding principal plus accrued interest divided by $ 0.86866 or (ii) the amount determined by dividing the conversion amount by the conversion price, with the conversion amount equal to the greater of a) the then outstanding principal plus accrued interest, or b) principal plus accrued interest through December 7, 2020 . The amendment of the 2020 Notes was accounted for as a modification, which required prospective consideration of the revised terms. For the year ended December 31, 2020, the Company recognized interest expense, including coupon interest and amortization of debt discounts, in connection with the 2020 Notes of $ 0.1 million. As further described below, the 2020 Notes were amended and settled in connection with the Corporate Reorganization in July 2020. Amendment and settlement of convertible notes As a condition of the closing of the Series D financing in July 2020, the Pfizer Note, 2018 Notes, 2019 Notes and 2020 Notes (and together, the “Convertible Notes”) were amended to settle the Convertible Notes into 59,164,808 Class D units of Himalaya Parent LLC. As of the settlement date, the aggregate outstanding principal and accrued interest of the Convertible Notes was $ 21.8 million and $ 4.7 million, respectively. The Pfizer Note converted into Class D units at a conversion price of $ 0.51554931 and the 2018 Notes and 2019 Notes converted into Class D units at a conversion price of $ 0.412439448 , which is 80% of the price paid by investors in the Series D financing. As of the July 10, 2020 settlement date, the Convertible Notes had a carrying value of $ 27.9 million, including related accrued interest, embedded derivatives and unamortized debt discounts. The fair value of the Class D units of Himalaya Parent LLC issued to the noteholders in exchange for the Convertible Notes was $ 30.6 million, resulting in a loss on extinguishment of convertible debt of $ 2.7 million. The fair value per unit of the Class D units of Himalaya Parent LLC was based on the fair value per share paid by investors in the Company’s Series D financing. Other Debt In April 2020, the Company borrowed $ 0.7 million under the Paycheck Protection Program (“PPP”) under the CARES Act. The loan 0.7 million balance of the forgiven loan was recognized as other income on the Company's Statement of Operations and Comprehensive Loss for the twelve months ended December 31, 2021.

Leases

Leases	12 Months Ended
	Dec. 31, 2021
Leases [Abstract]
Leases	5. Leases The Company has a single operating lease for its corporate headquarters and laboratory space in San Diego, California. The lease expires in July 2025 and the Company has an option to extend the term of the lease for an additional five years . However, it is not reasonably certain the Company will exercise the option to renew when the lease term ends and thus, the incremental term was excluded from the calculation of the lease liability. Additionally, the lease includes certain rent abatement, rent escalations, tenant improvement allowances and additional charges for common area maintenance and other costs. Supplemental balance sheet information related to lease liabilities at December 31, 2021, was as follows (in thousands): Lease-Related Assets and Liabilities Financial Statement Line Items As of December 31, 2021 Right-of-use assets: Operating leases Operating lease right-of-use assets $ 3,300 Total right-of-use assets $ 3,300 Lease Liabilities: Operating leases Operating lease liabilities $ 1,389 Operating lease liabilities, noncurrent 3,982 Total lease liabilities $ 5,371 The components of lease expense included in the Company’s consolidated statements of operations include (in thousands): Year Ended Operating lease expense $ 1,043 Variable lease expense 512 Total lease expense, net $ 1,555 Variable lease costs are primarily related to payments made to lessors for common area maintenance, property taxes, insurance, and other operating expenses. The Company did not have any short-term leases or finance leases for the year ended December 31, 2021. The weighted average remaining lease term and weighted average discount rate for operating leases as of December 31, 2021 were as follows: Year Ended Weighted average remaining lease term (in years) 3.5 Weighted average discount rate percentage 3.50 % Supplemental cash flow information related to leases under which the Company is the lessee was as follows (amounts in thousands): Year Ended Cash paid for amounts included in the measurement of operating leases $ 1,374 Maturities of operating lease liabilities as of December 31, 2021 were as follows (in thousands): Years ending December 31: Operating 2022 $ 1,555 2023 1,636 2024 1,685 2025 845 Thereafter — Total future lease payments 5,721 Less imputed interest ( 350 ) Total operating lease liabilities $ 5,371 As of December 31, 2020, prior to the Company’s adoption of ASC 842, annual minimum payments under noncancelable operating leases were as follows (in thousands): Years ending December 31: Operating 2021 $ 1,374 2022 1,555 2023 1,636 2024 1,685 Thereafter 845 Total minimum lease payments $ 7,095 Under ASC 840, during the years ended December 31, 2020 and 2019, net rent expense was $ 1.7 million and $ 1.1 million, respectively.

Commitments and contingencies

Commitments and contingencies	12 Months Ended
	Dec. 31, 2021
Commitments And Contingencies Disclosure [Abstract]
Commitments and contingencies	6. Commitments and contingencies From time to time, the Company may be subject to various claims and suits arising in the ordinary course of business. The Company is not currently a party to any legal proceedings the outcome of which the Company believes, if determined adversely to the Company, would individually or in the aggregate have a material adverse effect on the Company’s business, operating results or financial condition.

Convertible preferred stock and

Convertible preferred stock and members's/stockholders' equity (deficit)	12 Months Ended
	Dec. 31, 2021
Equity [Abstract]
Convertible preferred stock and members's/stockholders' equity (deficit)	7. Convertible preferred stock and members’/stockholders’ equity (deficit) Convertible preferred stock The Company had convertible preferred stock outstanding between the date of its Series D financing in July 2020 until the closing of its IPO in December 2020. The Company’s convertible preferred stock was classified as temporary equity in the accompanying consolidated balance sheets in accordance with authoritative guidance for the classification and measurement of potentially redeemable securities whose redemption is based upon certain change in control events outside of the Company’s control, including liquidation, sale or change of control of the Company. Because these change in control events were not probable, the Company did not adjust the carrying values of the convertible preferred stock to redemption value. Series D financing On July 13, 2020, BioAtla, Inc. entered into a Series D Preferred Stock Purchase Agreement, pursuant to which it issued 140,626,711 shares of Series D convertible preferred stock at $ 0.51554931 per share, for aggregate cash proceeds of $ 72.5 million. The Company incurred $ 4.3 million of issuance costs. Initial public offering and related transactions In December 2020, the Company completed its IPO selling 12,075,000 shares its common stock at $ 18.00 per share. Proceeds from the Company’s IPO, net of underwriting discounts and commissions and other offering costs, were $ 198.3 million. In connection with the IPO, all 199,791,519 shares of convertible preferred stock outstanding at the time of the IPO converted into 13,876,510 shares of the Company’s common stock and 1,492,059 shares of the Company’s Class B common stock. Private Placement of Common Stock In September 2021, the Company entered into agreements to sell 2,678,600 shares of its common stock at a price of $ 28.00 per share through a private investment in public equity financing (or "Private Placement"). Proceeds from the Private Placement, net of underwriting discounts and commissions and other offering costs, were $ 71.0 million. In connection with the Private Placement, the Company also issued registration rights to the investors. The Company filed a registration statement on Form S-1 (File No. 333-260440) with the SEC registering for resale the shares of common stock issued in the Private Placement. 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. Operating agreement Prior to the Corporate Reorganization, the Company’s operating agreement, as amended and restated, provided for classes of units, allocation of profits and losses, distribution preferences, other member rights and management of the LLC. The operating agreement designated Class A units, Class B units and Class C preferred units. The Class B units and Class C preferred units were non-voting, except as required by law. The Class B units were liability awards pursuant to authoritative guidance and, as such, were reported at fair value outside of members’ deficit. Members were limited in their liability to their capital contributions. Common stock warrants The Company issued the warrants described below in 2016 in connection with certain advisory services. The warrants became exercisable upon our IPO for a period of 365 and 450 days . Upon adoption of ASU No. 2018-07 on October 1, 2020, the measurement date of the warrants described below became fixed in accordance with the guidance, and such fair value was nominal since the warrants were deeply out-of-the-money. In December 2021, a total of 566,586 warrants with an exercise period of 365 days after our IPO expired unexercised. As of December 31, 2021 the remaining common stock warrants below are exercisable and expire as follows: Outstanding and exercisable Exercise price per share Expiration date 151,088 $ 132.37 March 12, 2022 Noncontrolling interests In December 2018, the Company issued a noncontrolling interest in HTKY in the form of ordinary shares in connection with the termination of a collaboration and license agreement. In addition to the ordinary shares issued, certain employees and shareholders of the Company purchased 19,000,000 ordinary shares of HTKY for an aggregate purchase price of $ 19,000 , of which 5,000,000 were repurchased for $ 5,000 in March 2019. As of December 31, 2019, the Company held all of the outstanding HTKY preferred equity, consisting of 97,183,256 Series B convertible preference shares, and 1,000 ordinary shares. The Series B convertible preference shares had a liquation preference equal to the greater of $ 1.00 per share, plus declared and unpaid dividends, or the if-converted value, and pay non-cumulative dividends in preference to the holders of ordinary shares at an annual rate of 7 % of the purchase price per share when, as and if declared by the board. The net income (loss) of HTKY was allocated to the ordinary shareholders on a pro rata basis. However, any net income was initially be allocated to the preference shares until the liquidation preference is met. Thereafter, preference shares would only be allocated dividends declared by the board of directors of HTKY. For the year ended December 31, 2019, substantially all of the $ 61,000 net loss of HTKY was allocated to the noncontrolling interest. HTKY had no material operations for the year ended December 31, 2020. As discussed in Note 1, HTKY was deconsolidated as part of the July 2020 Corporate Reorganization. 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, 2021 and 2020 , the total number of common shares authorized for issuance under the 2020 Plan was 6,226,540 and 4,939,678 , respectively. On January 1st of each year, commencing with the first January 1st following the effective date of the 2020 Plan, the shares authorized for issuance under the 2020 Plan shall be increased by a number of shares equal to the lesser of 4 % of the total number of shares outstanding on the immediately preceding December 31st and such lesser number of shares determined by the Company’s board of directors. The maximum term of the options granted under the 2020 Plan is no more than ten years . Awards under the 2020 Plan generally vest at 25 % one year from the vesting commencement date and ratably each month thereafter for a period of 36 months, subject to continuous service. Stock-based compensation expense recognized for all equity awards under the 2020 Plan has been reported in the consolidated statements of operations and comprehensive loss as follows (in thousands): Year ended Year ended Research and development $ 4,688 $ 740 General and administrative 20,429 2,282 Total $ 25,117 $ 3,022 Restricted stock units In December 2020, the Company granted an aggregate of 1,920,037 restricted stock units (“RSUs”) to certain of the Company’s employees and service providers, including executive officers and non-employee directors. The following table summarizes RSU activity under the 2020 Plan for the years ended December 31, 2021 and 2020: Number of Weighted - Outstanding at December 31, 2019 — $ — Granted 1,920,037 $ 18.00 Vested — $ — Outstanding at December 31, 2020 1,920,037 $ 18.00 Granted — $ — Vested 944,991 $ 18.00 Outstanding at December 31, 2021 975,046 $ 18.00 As of December 31, 2021 , total unrecognized stock-based compensation expense for RSUs was $ 17.5 million, which is expected to be recognized over a remaining weighted-average period of approximately 2.2 years. Stock options The following table summarizes stock option activity under the 2020 Plan for the year ended December 31, 2021 and 2020 (in thousands, except share and per option data and years): Number of Weighted - Weighted - Aggregate Balance at December 31, 2019 — $ — — $ — Granted 615,106 $ 18.00 Balance at December 31, 2020 615,106 $ 18.00 9.95 $ 9,848 Granted 479,543 $ 37.86 Exercised ( 7,747 ) $ 18.00 — $ 182,829 Balance at December 31, 2021 1,086,902 $ 26.76 9.22 $ 991,495 Vested and expected to vest at December 31, 2021 1,086,902 $ 26.76 9.22 $ 991,495 Exercisable at December 31, 2021 155,579 $ 18.31 8.97 $ 247,486 As of December 31, 2021 , total unrecognized stock-based compensation cost for unvested common stock options was $ 15.0 million, which is expected to be recognized over a remaining weighted-average period of approximately 3.1 years. The weighted- average grant date fair value of stock options granted during the years ended December 31, 2021 and 2020 was $ 24.61 per share and $ 11.66 per share, respectively. The total fair value of options vested during the year ended December 31, 2021 was $ 1.9 million. No options vested during the years ended December 31, 2020 and 2019. 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: Year ended Year ended Expected volatility 74.7 % 74.5 % Risk-free interest rate 1.06 % 0.52 % Expected dividend yield 0.0 % 0.0 % Expected term 5.98 years 6.09 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, 2021 and 2020 , a total of 833,993 and 464,829 shares, respectively, of common stock were authorized for issuance under the ESPP. The number of shares of common stock authorized for issuance will automatically increase on January 1 of each calendar year, from January 1, 2021 through January 1, 2030 by the least of (i) 1.0 % of the total number of common shares of our common stock outstanding on December 31 of the preceding calendar year (calculated on a fully diluted basis), (ii) 929,658 common shares or (iii) a number determined by the Company’s board of directors that is less than (i) and (ii) . The ESPP plan was amended in September 2021 to change the offering periods to end on May 15th and November 15th of each year beginning January 1, 2022. In February 2021, employees began to enroll in the ESPP and the Company’s first offering period commenced. ESPP purchase transactions occurred on June 30, 2021 and on December 31, 2021. During the year ended December 31, 2021, the Company issued 11,182 shares of common stock under the ESPP. As of December 31, 2021, 822,811 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, 2021 was immaterial. Common stock reserved for future issuance Common stock reserved for future issuance are as follows in common equivalent shares: December 31, December 31, Warrants for the purchase of common stock 151,088 717,674 Common stock options and restricted stock units issued and outstanding 2,061,948 2,535,143 Awards available for future issuance under the 2020 Plan 3,211,854 2,404,535 Awards available for future issuance under the ESPP 822,811 464,829 Total common stock reserved for future issuance 6,247,701 6,122,181

Profits interest incentive plan

Profits interest incentive plan	12 Months Ended
	Dec. 31, 2021
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Profits interest incentive plan	8. Profits interest incentive plan Prior to the Corporate Reorganization in July 2020, the Company maintained a Profits Interest Incentive Plan (the “Plan”) for selected employees, consultants and other service providers. In connection with the Corporate Reorganization, Himalaya Parent LLC assumed the Plan and the $ 1.0 million fair value of the liability was reclassified to additional paid-in capital. As of December 31, 2019, the Company had reserved a total of 16,665,977 Class B units for issuance under the Plan. The Class B units generally vested over four years , were subject to continued service requirements, and only provide the participants with benefits (in the form of distributions) if the distributions from BioAtla exceed specified threshold values. Generally, upon termination of services, all unvested Class B units were forfeited to the Company and the Company had the right, but not the obligation, to repurchase the vested Class B units within two years at the termination date fair value. The Class B unit repurchase would be settled in cash, at all times at the option of the Company, and the holder did not have the right to put the Class B units to the Company under any condition. Vested Class B units that are neither repurchased by the Company nor forfeited remained subject to the terms of the Company’s operating agreement. The Class B units were not subject to sale, assignment, transfer, pledge, or allowed to be otherwise encumbered or disposed of without prior written consent of the Company. No Class B units had been repurchased through the date of the Corporate Reorganization. Activity under the Plan is summarized as follows: Outstanding at December 31, 2019 14,478,949 Cancelled ( 170,836 ) Assumption of Plan by Himalaya Parent LLC on July 10, 2020 ( 14,308,113 ) Outstanding at December 31, 2020 — Vesting of Class B units under the Plan is summarized as follows: Unvested at December 31, 2019 6,158,328 Cancelled ( 170,836 ) Vested ( 1,310,807 ) Assumption of unvested Class B units by Himalaya Parent LLC on ( 4,676,685 ) Unvested at December 31, 2020 — The Class B units were liability awards pursuant to authoritative guidance, which required the Company to record a liability based on the fair value of the Class B units as of each reporting period. Through the date of the Corporate Reorganization, the fair value of the liability awards was determined based on the Company’s estimated enterprise value, which was allocated based on a hybrid model that, in addition to the option pricing model, considering the Company’s expected IPO. Under the option pricing method, units were valued by creating a series of call options with exercise prices based on the liquidation preferences and conversion terms of each unit class. In connection with the Division, the distribution thresholds that had to be achieved before the Class B unit holders were entitled to distributions were adjusted, resulting in a $ 0.9 million reduction to the aggregate profits interest liability between the Predecessor and the Post-Division LLCs at the date of the Division. The thresholds of the Post-Division Successor were changed in order to reflect the impact of the assets assigned to BioAtla Holdings and Inversagen in the Division. For the year ended December 31, 2019, the profits interest liability decreased $ 7.4 million, including the $0.9 million reduction described above, and $ 0.8 million recognized as additional paid-in capital related to the fair value of vested Class B units assumed by BioAtla Holdings and Inversagen in connection with the Division. In addition, the Company recognized stock-based compensation expense and additional paid-in capital of $ 0.2 million related to the fair value of the unvested Class B units assumed by BioAtla Holdings and Inversagen in connection with the Division since these Class B unit holders were employees of the Post-Division Successor, and were not expected to provide services to BioAtla Holdings or Inversagen. The following table provides a reconciliation of the profits interest liability (in thousands): Balance at December 31, 2019 8,592 Decrease in fair value of vested liability (Pre-Corporate Reorganization) recognized as decrease to stock-based ( 7,601 ) Fair value of vested liability assumed by Himalaya Parent LLC on July 10, 2020 recognized as additional paid-in ( 991 ) Balance at December 31, 2020 $ — The allocation of equity-based compensation, including $ 0.7 million from Himalaya Parent as a capital contribution during 2020, for all Class B units is as follows (in thousands): Years ended December 31, 2020 2019 Research and development $ ( 2,993 ) $ ( 2,997 ) General and administrative ( 3,859 ) ( 3,406 ) Total $ ( 6,852 ) $ ( 6,403 )

Collaboration, license and opti

Collaboration, license and option agreements	12 Months Ended
	Dec. 31, 2021
Collaboration License And Option Agreements [Abstract]
Collaboration, license and option agreements	9. Collaboration, license and option agreements Global Co-Development and Collaboration Agreement with BeiGene In April 2019, the Company entered into a Global Co-Development and Collaboration agreement (the “BeiGene Collaboration”) with BeiGene, Ltd. and BeiGene Switzerland GmbH (collectively “BeiGene”), a commercial-stage biopharmaceutical company, for the development, manufacturing and commercialization of the Company’s investigational CAB CTLA-4 antibody (BA3071). The Company and BeiGene amended the Global Co-Development and Collaboration agreement in December 2019 and in October 2020 (the “Amended BeiGene Collaboration”). Under the BeiGene Collaboration, the Company would co-develop the CAB-CTLA-4 antibody to reach defined early clinical objectives (“POC Milestone”), whereby the Company would perform the development activities and BeiGene would reimburse the Company for a portion of the costs incurred by the Company. Following the POC Milestone, BeiGene would then lead the parties’ joint efforts to develop the product candidate and be responsible for global regulatory filings and commercialization. BeiGene would be responsible for all costs of development, manufacturing and commercialization in China, parts of the Middle East and Asia (excluding Japan), Australia and New Zealand (the “BeiGene Territory”), and the parties would share development and manufacturing costs and commercial profits and losses upon specified terms in the rest of the world that are not part of the BeiGene Territory (the “ROW”). In 2019, BeiGene paid the Company an upfront non-refundable payment of $ 20.0 million and paid the Company $ 5.0 million for reimbursement of manufacturing costs. Under the BeiGene Collaboration, the Company was eligible to receive variable consideration for subsequent development and regulatory milestones globally and commercial milestones in the BeiGene Territory and tiered royalties ranging from the mid-single digits to the mid-double digits based on net sales in the BeiGene Territory. The Company concluded that the BeiGene Collaboration was a contract with a customer and applied relevant guidance from Topic 606 through reaching the POC milestone as the licenses to intellectual property granted to BeiGene and the obligation to perform research and development services are outputs of the Company’s ongoing activities. The Company identified material promises in the BeiGene Collaboration through POC Milestone, consisting of the licenses described above and the development services. It was determined that the licenses were not distinct from the development services resulting in a single performance obligation. In accordance with Topic 606, the Company determined the transaction price of the agreement was limited to the $ 25.0 million received, and excluded the variable consideration of expense reimbursements, milestone payments and royalties as they were fully constrained. The expense reimbursements were included in the transaction price in the reporting period the Company concluded it was probable that inclusion of such amounts in the transaction price would not result in a significant reversal in revenue recognized. As part of the Company’s evaluation of the milestone constraints, the Company determined the achievement of such milestones were contingent upon success of future developments, regulatory approvals and commercial activities which were not within its control and were uncertain. Variable consideration related to royalties would be recognized when the related sales occurred. Under the terms of the Amended BeiGene Collaboration, BeiGene was generally responsible for developing BA3071 and for global regulatory filings and commercialization. Subject to the terms of the Amended BeiGene Collaboration, BeiGene held an exclusive license with the Company to develop and manufacture the BA3071 candidate globally, and BeiGene was responsible for all costs of development, manufacturing and commercialization globally. The Amended BeiGene Collaboration provided that the Company was eligible to receive tiered royalties on sales worldwide, subsequent development and regulatory milestone payments globally and commercial milestones in the BeiGene territory. Under the Amended BeiGene Collaboration, the Company’s amended performance obligation would be satisfied at a point in time determined to be when BeiGene received the know-how and master cell bank for BA3071. Until then BeiGene could not benefit from the ability to further develop and manufacture the BA3071 candidate. Under the original collaboration agreement, the Company recognized revenue over time using an input method based on actual costs incurred compared to estimated total costs expected to be incurred to fulfill its performance obligation to perform development services. On November 18, 2021, the Company entered into Amendment No. 3 to the Amended BeiGene Collaboration (“Amendment No.3”). Under Amendment No. 3, the Amended BeiGene Collaboration was terminated, subject to survival of certain provisions, and BeiGene handed back rights to know-how and materials received under the Amended BeiGene Collaboration. As a result, the Company will assume responsibility for the global development and commercialization of BA3071. As consideration for Amendment No.3, the Company agreed to pay BeiGene mid-single digit royalties on sales worldwide and on a limited basis will share in any upfront and milestone payments received through a sublicense of BA3071. As part of Amendment No.3, the Company reclassified its remaining $ 19.8 million of deferred revenue as a long-term liability which is expected to settle as licensing payments are made to BeiGene in accordance with the resulting amendment. In the event the license is terminated, the liability will be extinguished with no further payment to BeiGene. For the year ended December 31, 2021, the Company did no t recognize any revenue related to the collaboration agreement with BeiGene. Collaboration revenue recognized for the years ended December 31, 2020 and 2019 was $ 0.4 million and $ 5.2 million, respectively. As of December 31, 2021 and December 31, 2020, the Company had a $ 19.8 million Liability to Licensor, and $ 19.8 million of deferred revenue which was classified as current, respectively. Service Contracts Prior to developing its own programs, the Company entered into various fixed price research services contracts. In connection with these service contracts, the Company may receive future milestone payments if certain clinical, regulatory and commercialization milestones are achieved. The Company is also eligible to receive royalties based on certain product sales. The Company recognized revenue of $ 0.3 million for the year ended December 31, 2021, related to the achievement of a clinical milestone on a fixed price service contract. License and Option Agreement with Pfizer, Inc. The Company was party to a license and option agreement with Pfizer that was terminated in December 2019 . Pfizer paid the Company $ 1.0 million in December 2015 upon execution of the agreement. The Company had identified a single deliverable at inception of the agreement, which consisted of the company’s obligation to nominate targets, perform certain preclinical research, efficacy studies and related reports (“research and development services”). These services were prerequisites to Pfizer’s exercise of Pfizer’s substantive options, including the option to obtain exclusive licenses to develop and commercialize a certain number of Antibody Drug Conjugates (“ADC”) CAB antibodies, under the agreement. As such, the Company recognized revenue for the consideration received over the four-year period over which it delivered its research and development services. In connection with the license and option agreement with Pfizer, the Company recognized collaboration revenue of $ 0.5 million for the year ended December 31, 2019.

Related party transactions

Related party transactions	12 Months Ended
	Dec. 31, 2021
Related Party Transactions [Abstract]
Related party transactions	10. Related party transactions Dr. Jay Short and Carolyn Anderson Short Dr. Jay Short and Carolyn Anderson Short loaned the Company $ 1.0 million and $ 0.5 million, respectively, under the terms of the 2019 Notes and 2020 Notes described in Note 4 above. For the years ended December 31, 2020 and 2019, the Company recognized interest expense (including amortization of debt discounts) of $ 0.1 million and $ 32,000 , respectively, on outstanding 2019 Notes and 2020 Notes payable to Dr. Jay Short and Carolyn Anderson Short. The 2019 Notes and 2020 Notes payable to Dr. Jay Short and Carolyn Anderson Short were settled in connection with the Corporate Reorganization in July 2020 . On March 18, 2021, the Company and Carolyn Anderson Short, its co-founder and former Chief of Intellectual Property & Strategy, mutually agreed that Ms. Short would depart the Company on May 31, 2021 following an agreed upon transition period. The Transition Agreement provides for the following severance benefits in exchange for a release of claims by Ms. Short: (i) a lump sum payment equal to eighteen (18) months of Ms. Short’s current base salary, (ii) a payment at her targeted bonus rate for 2021, pro-rated to the separation date, and (iii) accelerated full vesting of her equity awards including 7,747 stock options and 138,461 restricted stock units. The modification of these equity awards resulted in an incremental fair value of $ 7.0 million which was recognized on a straight-line basis over the transition service period. For the twelve months ended December 31, 2021, the Company recognized $ 1.0 million related to the lump sum salary payment and target bonus. The Company also recognized non-cash stock-based compensation charges of $ 9.4 million related to the modified equity awards for the twelve months ended December 31, 2021. No unrecognized stock-based compensation remained as of December 31, 2021. Ms. Short exercised her 7,747 stock options in 2021, therefore there are no remaining options outstanding related to Ms. Short’s transition agreement as of December 31, 2021. Inversagen, LLC Inversagen was formed in conjunction with the LLC Division. On March 15, 2019, the Company entered into an Exclusive License Agreement with Inversagen (the “Inversagen License”). Under the terms of the agreement, Inversagen acquired the rights to CAB-antibodies for the field of diseases associated with aging, outside of cancer, and an immuno-oncology antibody. The Company may perform development services under the agreement and will be reimbursed by Inversagen for its costs. Commencing on the first commercial sale of the CAB-antibodies and immuno-oncology antibody subject to the Inversagen License, Inversagen will pay the Company milestone payments and royalties, which represent a variable interest held by the Company. On July 7, 2020, the Company and Inversagen entered into the First Amendment to Exclusive License Agreement (“Amended Inversagen License”), which grants the Company an option for a period of 10 years to acquire the immuno-oncology antibody in return for royalty payments in the low-single digits during the applicable royalty term. No payments have been made to date. Inversagen has only nominal assets and liabilities and is a VIE as the entity lacks sufficient equity to finance its activities without additional subordinated financial support. The Company does not consolidate Inversagen as it is not the primary beneficiary; Inversagen License and the Amended Inversagen License did not and do not provide the Company with any decision-making power over the activities that are most significant to the entity’s economic success, such as the direction of its development efforts or the search for or terms of any future financing arrangements. The Company has no equity interest in Inversagen, and no exposure to its losses. Inversagen is currently inactive, and the Company has not provided any services to Inversagen, has not provided any support to Inversagen and has no obligation to do so, and Inversagen’s creditors have no recourse to the general credit of the Company. The Company does no t have any assets or liabilities associated with its variable interest in Inversagen at December 31, 2021 and 2020. Inversagen is a related party of the Company. Dr. Jay Short and his spouse, Carolyn Anderson Short, serve as managers of Inversagen. BioAtla Holdings, LLC Effective January 1, 2020, the Company entered into an Exclusive License Agreement (the “BioAtla Holdings License”) with BioAtla Holdings, LLC. Under the terms of the agreement, BioAtla Holdings acquired the rights to CAB antibodies for certain targets in the field of Adoptive Cell Therapy (CAR-T format) in exchange for potential royalty payments on future net sales. On July 7, 2020, the Company and BioAtla Holdings entered into the First Amendment to Exclusive License Agreement (the “Amended BioAtla Holdings License”), which grants the Company an option for a period of 10 years to acquire the ACT Preparations and ACT Treatments in return for royalty payments in the low-single digits during the applicable royalty term. The Company has not exercised its option and no payments have been made to date under these agreements. In addition, effective January 1, 2020, the Company entered into a Royalty Sharing Agreement whereby the Company agreed to share with BioAtla Holdings 50 % of the royalties it receives under the Amended and Restated EXUMA License defined and described in Note 12 below. BioAtla Holdings is a variable interest entity as it does not have sufficient equity to finance its activities without additional subordinated financial support. The royalty payments and option to acquire assets represent variable interests held by the Company in BioAtla Holdings. The Company is not the primary beneficiary of BioAtla Holdings, however, as the BioAtla Holdings License and Amended BioAtla Holdings License did not and do not provide the Company with any decision-making power over the activities that are most significant to the entity’s economic success, such as the direction of its development efforts or the search for or terms of any future financing arrangements. The Company has no equity interest in BioAtla Holdings, and no exposure to its losses. BioAtla Holdings is currently inactive, and the Company has not provided any support to BioAtla Holdings and has no obligation to do so, and BioAtla Holdings’ creditors have no recourse to the general credit of the Company. The Company does no t have any assets or liabilities associated with its variable interests in BioAtla Holdings at December 31, 2021 and 2020. BioAtla Holdings is a related party of the Company. Dr. Jay Short and his spouse, Carolyn Anderson Short, serve as managers of BioAtla Holdings. Himalaya Therapeutics SEZC Prior to the Corporate Reorganization, Himalaya Therapeutics SEZC met the definition of a VIE under ASC 810-10, as the entity did not have enough equity to finance its activities without additional subordinated financial support. The Company consolidated Himalaya Therapeutics SEZC as the primary beneficiary, as it had (i) the power to direct activities of a VIE that most significantly impact the VIE’s economic performance and (ii) the right to receive benefits from the VIE that could potentially be significant to the VIE, resulting from its control of the board of directors, and voting control of the entity via a voting agreement among its shareholders, and its equity holdings. The Company was not obligated to provide financial support to Himalaya Therapeutics SEZC. Himalaya Therapeutics SEZC’s creditors had no recourse in the general credit of the Company. Himalaya Therapeutics SEZC held intellectual property related to certain CAB Antibodies under an Exclusive Rights Agreement with the Company dated December 20, 2018. As of December 31, 2019, Himalaya Therapeutics SEZC had no material operations, did not have any employees and the carrying value of its assets and liabilities was nominal. 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 us 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. As part of the Corporate Reorganization, Himalaya Therapeutics SEZC was distributed to Himalaya Parent LLC at the carrying value of its assets and liabilities, which were nominal, and no gain or loss was recorded on the transaction in the Company’s financial statements for the year ended December 31, 2020. Himalaya Therapeutics SEZC continues to be a variable interest entity as it does not have sufficient equity to finance its activities without additional subordinated financial support. The Company is not obligated to provide financial support to Himalaya Therapeutics SEZC. The Company is not the primary beneficiary of Himalaya Therapeutics SEZC, however, as the Amended Rights Agreement does not provide BioAtla, Inc. with the power to direct activities of a VIE that most significantly impact the VIE’s economic performance, such as decision-making power over the direction of its development efforts or the search for or terms of any future financing arrangements. The Company does no t have any assets or liabilities recorded at December 31, 2020 associated with its variable interest in Himalaya Therapeutics SEZC, and has no exposure to Himalaya Therapeutics SEZC losses. The Company does not have a variable interest in Himalaya Parent LLC. Himalaya Therapeutics SEZC is a related party whose controlling shareholder is Himalaya Parent LLC. Dr. Jay Short and his spouse, Carolyn Anderson Short, serve as directors of Himalaya Therapeutics SEZC, and Carolyn Anderson Short serves as an officer of such entity. Himalaya Parent LLC In connection with the Corporate Reorganization, Himalaya Parent assumed the Company’s profits interest plan, including equity awards to employees of the Company. For the years ended December 31, 2021 and 2020, the Company recognized $ 0 and $ 0.7 million, respectively, of compensation cost and a related capital adjustment in connection with the assumed profits interest plan. Dr. Jay Short and his spouse, Carolyn Anderson Short, serve as managers of Himalaya Parent LLC. EXUMA Biotech Corp. and subsidiary As of December 31, 2019, the Company and EXUMA are no longer related parties since none of the Post-Division LLCs own any common or preferred stock of EXUMA and have no ongoing contractual relationships other than the license agreement described below (see Note 12). The Company was a named party to a lease where a subsidiary of EXUMA was the primary tenant. The EXUMA subsidiary paid the landlord directly for payments due under the lease and was reimbursed by the Company for its share of the payments. For the year ended December 31, 2019, the Company expensed $ 15,000 for its share of payments due under the lease. In addition, the Company expensed $ 10,000 related to a November 2019 amendment of the license agreement described in Note 12. Biotech Investment Group, LLC Prior to the Corporate Reorganization, Biotech Investment Group, LLC (“BIG”), was a principal owner, related party of the Company and affiliated with BioDuro, LLC (“BioDuro”) and Biotech Investment Group II LLC (“BIG II”). Subsequent to the Corporate Reorganization, BIG is no longer a principal owner and, as a result, neither BIG nor its affiliates are related parties of the Company. BioDuro-Sundia BioDuro-Sundia is a contract research organization that provides services to the Company. For the year ended December 31, 2019, the Company incurred expenses of $ 1.9 million in connection with services provided by BioDuro-Sundia. During 2019, an affiliate of BIG sold a majority interest in BioDuro-Sundia to an unaffiliated entity. Effective January 1, 2020, BioDuro-Sundia is no longer considered a related party of the Company. Biotech Investment Group II LLC BIG II loaned the Company $ 0.5 million under the terms of the 2019 Notes described in Note 4 above. For the years ended December 31, 2020 and 2019, the Company recognized interest expense (including amortization of debt discounts) of $ 42,000 and $ 20,000 , respectively on outstanding 2019 Notes payable to BIG II. The 2019 Notes payable to BIG II were settled in connection with the Corporate Reorganization in July 2020. Private Placement of Common Stock As part of the 2021 Private Placement, the Company issued 625,000 shares of common stock for total net proceeds of $ 17.5 million to certain stockholders considered to be related parties.

401(k) plan

401(k) plan	12 Months Ended
	Dec. 31, 2021
Compensation And Retirement Disclosure [Abstract]
401(k) plan	11. 401(k) plan The Company maintains a defined contribution 401(k) plan available to eligible employees. Employee contributions are voluntary and are determined on an individual basis, limited to the maximum amount allowable under federal tax regulations. The Company, at its discretion, may make certain matching contributions to the 401(k) plan. To date, the Company has no t made any matching contributions.

EXUMA Biotech Corp.

EXUMA Biotech Corp.	12 Months Ended
	Dec. 31, 2021
Obligation with Joint and Several Liability Arrangement [Abstract]
EXUMA Biotech Corp.	12. EXUMA Biotech Corp. Exclusive License Agreement Under an Exclusive License Agreement entered into in May 2016, the Company granted EXUMA and its affiliates an exclusive, worldwide, sublicensable license under certain patents and know-how controlled by the Company to develop, manufacture and commercialize Adoptive Cellular Therapy (“ACT”) preparations and treatments for cancer. EXUMA’s rights under the agreement exclude the right to grant sublicenses to third parties to discover, develop or manufacture any CAB ACT or any component of the Company’s CAB ACT technology, except as used in or incorporated into EXUMA’s ACTs for cancer. The license to EXUMA is royalty bearing. EXUMA granted the Company an exclusive, worldwide, royalty free, fully paid-up, sublicensable license under certain patents and know-how controlled by EXUMA and EXUMA’s interest in technology jointly developed under the agreement to develop, manufacture and commercialize non-ACT CAB products for any indication. EXUMA is obligated to pay the Company during the royalty term, on a product-by-product basis and country-by-country basis, mid-single digit royalties based on annual net sales of certain EXUMA ACT products, subject to certain adjustments. The term during which EXUMA is obligated to pay royalties under the agreement with respect to any particular product in any particular country, will begin on the first commercial sale of such product in such country and will end on the date of expiration of the last-to-expire of certain product-related patent rights in such country. All royalties to be paid under the agreement are subject to certain adjustments. Future royalties will be recognized when earned. Unless earlier terminated, the agreement continues in effect so long as EXUMA or any of its affiliates, licensees or sublicensees are developing or commercializing any EXUMA products in the ACT field or the Company or any of its affiliates, licensees or sublicensees are developing or commercializing any CAB products for any indication outside the ACT field. The agreement may be terminated only by the mutual written agreement of the parties. In connection with the Exclusive License Agreement, the Pre-Division Predecessor received common and preferred stock of EXUMA. The preferred stock was accounted for as a cost method investment and the common stock was accounted for as an equity method investment. Both the cost method investment and equity method investment had initial carrying values of zero and neither resulted in adjustments to the consolidated statements of operations for the years ended December 31, 2019. These holdings of EXUMA common and preferred stock were retained by BioAtla Holdings in connection with the LLC Division. In November 2019, the Company entered into an Amended and Restated Exclusive License Agreement with EXUMA (the “Amended and Restated EXUMA License”). The Amended and Restated EXUMA License curtailed the rights to certain CAB intellectual property previously licensed to EXUMA in exchange for a one-time, non-refundable, non-creditable license fee of $ 10,000 . More specifically, the Amended and Restated EXUMA License limits CAB ACT products to four specified targets, and BioAtla is no longer obligated to provide new targets to EXUMA. The Amended and Restated EXUMA License does not change EXUMA’s obligation to pay BioAtla royalties on licensed products. In connection with the Amended and Restated EXUMA License, BioAtla Holdings sold its EXUMA common and preferred holdings back to EXUMA for consideration of $ 25,000 . The Company concluded that the Amended and Restated EXUMA License was priced at fair value and was not influenced by the pricing of the contemporaneous related party stock sale. EXUMA is a VIE, and the Company has a variable interest in EXUMA due to its right to receive royalties during the royalty term under the Amended and Restated EXUMA License. As of December 31, 2021 and 2020, the Company has determined it is not the primary beneficiary of EXUMA and, as such, the Company does not consolidate EXUMA. The Company has no equity ownership in EXUMA, no representation on the EXUMA board of directors, and the Amended and Restated EXUMA License does not provide the Company with the ability to make decisions regarding the execution of business strategy that most significantly impact the economic performance of EXUMA. The Company has not funded and has no commitment to fund EXUMA’s losses, and has no exposure to loss as a result of its Amended and Restated EXUMA License. The Company’s financial statements do not include any assets or liabilities related to the Amended and Restated EXUMA License at December 31, 2021 and 2020.

Income taxes

Income taxes	12 Months Ended
	Dec. 31, 2021
Income Tax Disclosure [Abstract]
Income taxes	13. Income taxes Historically, the Company had conducted its U.S. operations through a pass through entity that filed its income tax returns as a partnership for federal and state income tax purposes. As a result, the Company was not subject to U.S. federal or state income taxes as the related tax consequences were reported by its individual members. In July 2020, the Company changed its status from a limited liability company to a corporation, and accordingly, the Company became taxable at the entity level for U.S. federal and state tax purposes. 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): Year ended Year ended Tax computed at the federal statutory rate $ ( 20,034 ) $ ( 7,529 ) Deferred impact of conversion to C Corporation ( 2,131 ) ( 6,708 ) Partnership income not subject to tax — 1,837 Nondeductible executive compensation 4,145 — Stock-based compensation ( 1,021 ) — Research and development and orphan drug credits ( 3,091 ) ( 807 ) Uncertain tax positions 757 197 Other, net 793 242 Valuation allowance 20,582 12,768 Income tax expense $ — $ — The Company’s net deferred tax assets (liabilities) are as follows (in thousands): December 31, December 31, Deferred tax assets: Net operating loss carryforwards $ 21,935 $ 5,607 Guaranteed payments — 1,702 Liability to licensor 4,159 — Deferred revenue — 4,159 Goodwill 3,449 — Deferred rent — 504 Lease liability 1,128 — Accrued compensation 485 585 Research credit carryforwards 2,945 610 Stock-based compensation 697 438 Other 2 0 Gross deferred tax assets 34,800 13,605 Less valuation allowance ( 33,351 ) ( 12,768 ) Total deferred tax assets 1,449 837 Deferred tax liabilities: Fixed assets ( 756 ) ( 837 ) Operating lease right-of-use asset ( 693 ) — Total deferred tax liabilities ( 1,449 ) ( 837 ) Net deferred tax assets $ — $ — A valuation allowance of approximately $ 33.4 million as of December 31, 2021 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 $ 20.6 million during 2021. At December 31, 2021 , the Company had federal net operating loss carryforwards of approximately $ 104.5 million. The federal net operating losses can be carried forward indefinitely, subject to an 80% limitation against taxable income. At December 31, 2021 , the Company had federal and California research and development credit carryforwards of approximately $ 1.9 million and $ 1.2 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, 2021, the Company also had federal orphan drug credit carryforwards of approximately $ 1.0 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. On March 27, 2020, the Coronavirus Aid, Relief, and Economic Security Act (“CARES” Act) was enacted in response to the COVID-19 pandemic. The CARES Act, among other things, permits net operating loss carryovers and carrybacks to offset 100 % of taxable income for taxable years beginning before 2021. In addition, the CARES Act allows net operating losses incurred in 2018, 2019, and 2020 to be carried back to each of the five preceding taxable years to generate a refund of previously paid income taxes. As the Company operated as a partnership during the carryback period, net operating loss carrybacks will not be allowed. Due to the Company’s history of net operating losses, other provisions of the CARES Act are not expected to have a material impact on the Company’s financial statements. Pursuant to the Paycheck Protection Program (the “PPP”) of the CARES Act, the Company received a PPP loan in the amount of $ 0.7 million. In 2021, the Company received forgiveness of the PPP loan. The loan forgiveness income is not considered taxable for Federal or state income tax purposes. In accordance with the Consolidated Appropriations Act, 2021 (CAA) enacted on December 27, 2020, certain qualified expenses used with the funds of the PPP Loan are fully deductible for Federal income tax purposes; however, California does not conform to this aspect of the CAA. Under the FASB's accounting guidance related to income tax positions, among other things, the impact of an uncertain income tax position on the income tax return must be recognized at the largest amount that is more-likely-than-not to be sustained upon audit by the relevant taxing authority. An uncertain income tax position will not be recognized if it has less than a 50% likelihood of being sustained. Additionally, the guidance provides guidance on derecognition, classification, interest and penalties, accounting in interim period, disclosure and transition. The Company regularly evaluates the likelihood of recognizing the benefit for income tax positions taken in various federal and state filings by considering all relevant facts, circumstances, and information available. The following table summarizes the reconciliation of the unrecognized tax benefits activity during the year ended December 31, 2021 (in thousands): Balance as of December 31, 2019 $ — Gross increase – current-period tax positions 210 Balance as of December 31, 2020 $ 210 Gross increase – current-period tax positions 801 Balance as of December 31, 2021 $ 1,011 As of December 31, 2021 , the Company had gross unrecognized tax benefits of approximately $ 1.0 million, none of which would affect the Company’s effective tax rate due to the existence of the valuation allowance. The Company’s policy is to recognize interest and penalties related to income tax matters in income tax expense. The Company had no accrual for interest or penalties on the Company’s consolidated balance sheet and has not recognized interest or penalties in the consolidated statements of net and comprehensive income for the year ended December 31, 2021. 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 2018 and 2017, respectively, and forward. However, any adjustment made for the period prior to the conversion to C Corporation in July 2020 would be passed through to the Company's former members. Post-conversion to C Corporation, to the extent allowed by law, the taxing authorities may have the right to examine periods where NOLs and research and development credits were generated and carried forward, and make adjustments to the amount of the NOL and research credits carryforward amount. The Company is not currently under examination by any jurisdiction.

Subsequent events

Subsequent events	12 Months Ended
	Dec. 31, 2021
Subsequent Events [Abstract]
Subsequent events	14. Subsequent events The Company has completed an evaluation of all subsequent events through February 28, 2022 for the financial statements as of and for the year ended December 31, 2021 to ensure these consolidated financial statements include appropriate disclosure of events both recognized in the consolidated financial statements and events which occurred but were not recognized in the consolidated financial statements. Except as described below or elsewhere in these consolidated financial statements, the Company has concluded that no subsequent event has occurred that requires disclosure. On January 5, 2022, BioAtla and Bristol-Myers Squibb Company (“BMS”) entered into a clinical trial collaboration and supply agreement (the “BMS Agreement”). Under the terms of the BMS Agreement, BioAtla and BMS will collaborate on clinical trials of separate combination therapies using two of BioAtla’s Conditionally Active Biologic Antibody Drug Conjugates, BA3011 and BA3021, each in combination with Opdivo® (nivolumab), BMS’ proprietary anti-PD-1 monoclonal antibody product. The Company will serve as the study sponsor of the scheduled studies and will be responsible for costs associated with the trial execution. BMS will provide Opdivo® clinical drug supply at no cost for the combination study trials. After the completion of the combination therapy trials, the Company is obligated to provide BMS with a final report of the data resulting from the trial. There was no impact to the Company's financial results for the year ended December 31, 2021 as a result of this agreement.

Organization and summary of s_2

Organization and summary of significant accounting policies (Policies)	12 Months Ended
	Dec. 31, 2021
Accounting Policies [Abstract]
Organization	Organization BioAtla, LLC was formed in Delaware in March 2007 and, after undergoing two separate reorganizations that are further discussed below, was converted to a Delaware corporation in July 2020 and was renamed BioAtla, Inc. (BioAtla, Inc. together with the Pre-Division Predecessor and the Post-Division Successor as defined below, 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. LLC Division In March 2019, BioAtla, LLC (the "Pre-Division Predecessor") was divided into three separate and distinct Delaware limited liability companies (the “Division”) as follows: 1) BioAtla, LLC renamed to BioAtla Holdings, LLC (“BioAtla Holdings”), 2) a new legal entity named Inversagen, LLC (“Inversagen”), and 3) a new legal entity named BioAtla, LLC (the “Post-Division Successor” and together with BioAtla Holdings and Inversagen, the “Post-Division LLCs”). Upon the Division, each Post-Division LLC had substantially the same form of operating agreement and capital structure as the Pre-Division Predecessor, with the following exceptions: i) 1,750,000 Class B units issued by the Post-Division Successor but not by BioAtla Holdings or Inversagen, ii) the outstanding warrants of the Pre-Division Predecessor at the Division date were transferred to the Post-Division Successor (see Note 7), and iii) the Class C units of the Post-Division Successor had liquidation preferences and a preferred return not included in the operating agreements of BioAtla Holdings and Inversagen. In connection with the Division, the Pre-Division Predecessor’s holdings of EXUMA Biotech Corp. (“EXUMA”, formerly F1 Oncology, Inc.) common and preferred stock (see Note 12) remained in BioAtla Holdings and certain rights related to the application of CAB technology in senescent cell therapy were transferred to the Post-Division Successor and simultaneously licensed to Inversagen (see Note 10). The remaining assets and liabilities (including ownership of Himalaya Therapeutics SEZC, or "HTKY", and its wholly-owned subsidiary, Himalaya Therapeutics HK Limited as described below in “Principles of consolidation and deconsolidation”), and substantially all of the operations of the Pre-Division Predecessor, including all existing employees, were transferred to the Post-Division Successor. Each of the Pre-Division Predecessor’s members at the time of the Division continued as a member in the Post-Division Successor, BioAtla Holdings and Inversagen, and each entity has Dr. Jay Short and his spouse, Carolyn Anderson Short, as its LLC managers. There are no shared services agreements between the Company and BioAtla Holdings or Inversagen. The Company has determined that Inversagen is a variable interest entity (“VIE”), the Company is not the primary beneficiary of Inversagen, and that the Post-Division LLCs are under the common control of Jay and Carolyn Short. The Company does not consolidate either BioAtla Holdings or Inversagen (see Note 10). In addition, the Company has no direct equity investment in either BioAtla Holdings or Inversagen that require either equity method or cost method accounting. The assets, liabilities, and employees transferred to the Post-Division Successor in the Division met the definition of a business and the transfer qualifies as a change in reporting entity under Accounting Standards Codification (“ASC”) 250-10-45-21. As such, the historical financial statements of the Pre-Division Predecessor are deemed to be those of the Post-Division Successor, even for periods prior to its formation. As a transfer of a business to an entity under common control, the assets and liabilities of the Pre-Division Predecessor were transferred to the Post-Division Successor at historical carrying values. At the Division date, the Pre-Division Predecessor’s investment in EXUMA and the assets licensed to Inversagen had a zero carrying value and neither EXUMA nor Inversagen had material operations. As such, the Pre-Division historical financial statements presented herein are the historical financial statements of the Pre-Division Predecessor without adjustment. In connection with the Division, certain modifications were made to then outstanding debt agreements and units, including: i) the participation threshold of each Class B unit in each Post-Division LLC was adjusted for the impact of the Division (see Note 8), ii) the amendment of the Pfizer Note and 2018 Notes (as defined and described in Note 4), and iii) the issuance, to both Pfizer and the holders of the 2018 Notes, of conditional warrants by BioAtla Holdings and Inversagen which become exercisable upon the conversion of the Pfizer Note and 2018 Notes into capital stock of the Post-Division Successor (see Note 4). The Post-Division Successor converted to a Delaware corporation in July 2020 as part of the Corporate Reorganization defined and described below, and was renamed BioAtla, Inc. BioAtla, Inc. is the final successor to the Pre-Division Predecessor and the Post-Division Successor, and collectively these entities are referred to as “the Company.” The historical financial statements of the Company prior to the Corporate Reorganization are those of the Pre-Division Predecessor and the Post-Division Successor without adjustment.
Corporate reorganization and series D financing	Corporate Reorganization and Series D Financing In July 2020, BioAtla, LLC (the Post-Division Successor) completed a series of transactions (the “Corporate Reorganization”) in connection with the conversion from a limited liability company into a Delaware corporation, the spin-off of Himalaya Therapeutics SEZC, and the completion of a Series D convertible preferred stock financing. The Corporate Reorganization involved the formation of Himalaya Parent LLC as a wholly owned subsidiary of BioAtla, LLC and the formation of BioAtla MergerSub LLC, as a wholly owned subsidiary of Himalaya Parent LLC. Under the Agreement and Plan of Merger (the “Merger Agreement”), BioAtla, LLC was merged into and with BioAtla MergerSub LLC, with BioAtla, LLC surviving, and the members of BioAtla, LLC immediately prior to the effective time of the Merger Agreement received membership interests, on a one-for-one basis, of Himalaya Parent LLC as consideration, and the then-outstanding warrants to purchase equity of BioAtla, LLC were converted into warrants to purchase common shares of common stock of BioAtla, Inc. (see Note 7). The Himalaya Parent LLC operating agreement provided identical equity rights for the then outstanding units of BioAtla, LLC. In addition: (i) the membership interests of BioAtla, LLC held by Himalaya Parent LLC were exchanged for 6,220,050 shares of BioAtla, Inc. common stock, (ii) BioAtla, Inc. issued an aggregate of 59,164,808 shares of Series D convertible preferred stock to Himalaya Parent LLC and Himalaya Parent LLC issued an aggregate of 59,164,808 Class D units to the holders of convertible notes of BioAtla, LLC in connection with the conversion of their convertible notes into Class D units of Himalaya Parent LLC (see Note 4), (iii) BioAtla, LLC distributed to Himalaya Parent LLC its equity interests in Himalaya Therapeutics SEZC, a then majority-owned subsidiary which is engaged in the development of a set of antibodies in the field of oncology primarily in Greater China, (iv) Himalaya Parent LLC assumed the profits interest liability of BioAtla, LLC (see Note 8) and (v) BioAtla, LLC converted into a Delaware corporation pursuant to a statutory conversion and changed its name to BioAtla, Inc. Following the Corporate Reorganization, Himalaya Parent LLC owned 59,164,808 shares of BioAtla, Inc. Series D convertible preferred stock and 6,220,050 shares of BioAtla, Inc. common stock, all of which were subsequently distributed ("the Distribution") to the members of Himalaya Parent, LLC. As a result of the sale of 140,626,711 shares of Series D convertible preferred stock to new investors in July 2020 (see Note 7), BioAtla, Inc. was not controlled by Himalaya Parent LLC and BioAtla, Inc. does not control Himalaya Parent LLC subsequent to the distribution discussed in item (iii) above (see further discussion in “Principles of consolidation and deconsolidation” below). All pre-Corporate Reorganization operations, employees, property, assets and obligations of BioAtla, LLC (exclusive of the profits interest liability and Himalaya Therapeutics SEZC now held by Himalaya Parent LLC) are held by BioAtla, Inc. Shares of Series D convertible preferred stock were subsequently converted into common stock as part of the Company’s initial public offering (“IPO”) in December 2020.
Reverse stock split	Reverse Stock Split On December 2, 2020, the Company effected a 1-for-13 reverse stock split of its common stock. The par value and the authorized shares of the common stock were not adjusted as a result of the reverse stock split. The reverse stock split resulted in an adjustment to the convertible preferred stock conversion price to reflect a proportional decrease in the number of shares of common stock to be issued upon conversion. The accompanying financial statements and notes to the financial statements give retroactive effect to the reverse stock split. No adjustments have been made to any period for the units outstanding prior to the LLC Conversion.
Principles of consolidation and deconsolidation	Principles of Consolidation and Deconsolidation Prior to the Corporate Reorganization in July 2020, the consolidated financial statements included the accounts of BioAtla, LLC and those of its majority owned subsidiary Himalaya Therapeutics SEZC that had no material operations. Himalaya Therapeutics SEZC also had a wholly owned subsidiary, Himalaya Therapeutics HK Limited that had no material operations. All intercompany balances were eliminated in consolidation. In connection with the Corporate Reorganization, Himalaya Therapeutics SEZC and Himalaya Therapeutics HK Limited were deconsolidated without material impact to the consolidated financial statements. Subsequent to the Corporate Reorganization and subsequent to the Distribution as defined and described above, Himalaya Parent LLC does not control, is not under common control with, and is not consolidated by BioAtla, Inc. and BioAtla, Inc. is a single legal entity with no consolidated variable interest entities ("VIEs") or subsidiaries (see Note 10).
Liquidity and going concern	Liquidity and Going Concern The Company has incurred cumulative operating losses and negative cash flows from operations since its inception and expects to continue to incur significant expenses and operating losses for the foreseeable future as it continues the development of its product candidates. As of December 31, 2021, the Company had an accumulated deficit of $ 186.3 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. Management is required to perform a two-step analysis of the Company’s ability to continue as a going concern. Management must first evaluate whether there are conditions and events that raise substantial doubt about the Company’s ability to continue as a going concern (Step 1). If management concludes that substantial doubt is raised, management is also required to consider whether its plans alleviate that doubt (Step 2). Management’s assessment included the preparation of cash flow forecasts resulting in management’s conclusion that there is not substantial doubt about the Company’s ability to continue as a going concern for 12 months after the date the consolidated financial statements for the year ended December 31, 2021 are issued.
Variable interest entities	Variable Interest Entities The Company consolidates entities in which it has a controlling financial interest. The Company determines whether it has a controlling financial interest in an entity by first evaluating whether the entity is a voting interest entity or a variable interest entity (“VIE”). VIEs are entities in which (i) the total equity investment at risk is sufficient to enable the entity to finance its activities independently, (ii) the equity holders have the power to direct the activities of the entity that most significantly impact its economic performance, the obligation to absorb the losses of the entity and the right to receive the residual returns of the entity and (iii) the legal entity is structured with substantive voting rights. A VIE is an entity that lacks one or more of the characteristics of a voting interest entity. The Company has a controlling financial interest in a VIE when the Company has a variable interest or interests that provide it with (i) the power to direct the activities of the VIE that most significantly impact the VIE’s economic performance and (ii) the obligation to absorb losses of the VIE or the right to receive benefits from the VIE that could potentially be significant to the VIE. The Company evaluates its relationships with its VIEs on an ongoing basis to determine whether or not it has a controlling financial interest (see Notes 10 and 12).
Use of estimates	Use of Estimates The Company’s consolidated financial statements are prepared in accordance with U.S. generally accepted accounting principles (“GAAP”). The preparation of the Company’s consolidated financial statements requires it to make estimates and assumptions that impact the reported amounts of assets, liabilities, revenues and expenses and the disclosure of contingent assets and liabilities in the Company’s consolidated financial statements and accompanying notes. The most significant estimates in the Company’s consolidated financial statements relate to revenue recognition, accruals for research and development costs, equity-based compensation and fair value measurements. These estimates and assumptions are based on current facts, historical experience and various other factors believed to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities and the recording of revenue and expenses that are not readily apparent from other sources. Actual results may differ materially and adversely from these estimates. To the extent there are material differences between the estimates and actual results, the Company’s future results of operations will be affected.
Segment reporting	Segment Reporting Operating segments are identified as components of an enterprise about which separate discrete financial information is available for evaluation by the chief operating decision-maker in making decisions regarding resource allocation and assessing performance. The Company views its operations and manages its business in one operating segment.
Cash and cash equivalents	Cash and Cash Equivalents The Company considers all highly liquid investments with original maturities of three months or less when purchased to be cash equivalents.
Concentration of risk	Concentrations of Risk Financial instruments that potentially subject the Company to a significant concentration of credit risk consist primarily of cash and cash equivalents. The Company maintains deposits in federally insured financial institutions in excess of federally insured limits. The Company has not experienced any losses in such accounts and management believes that the Company is not exposed to significant credit risk due to the financial position of the depository institutions in which those deposits are held. For the years ended December 31, 2021, 2020, and 2019 , BeiGene, as defined and described in Note 9, represented 0 %, 100 % and 91 %, respectively, of total revenues.
Property and equipment	Property and Equipment Property and equipment are stated at cost and depreciated on a straight-line basis over the estimated useful life of the related assets. Leasehold improvements are stated at cost and amortized on a straight-line basis over the lesser of the remaining term of the related lease or the estimated useful life of the leasehold improvements. Repairs and maintenance costs are charged to expense as incurred and expenditures that materially extend the useful lives of assets are capitalized.
Impairment of long-lived assets	Impairment of Long-Lived Assets The Company reviews long-lived assets, such as property and equipment, for impairment whenever events or changes in circumstances indicate the carrying amount of an asset may not be recoverable. Recoverability of assets to be held and used is measured by a comparison of the carrying amount of an asset to the future undiscounted net cash flows expected to be generated by the asset. If such assets are considered to be impaired, the impairment to be recognized is measured as the amount by which the carrying amount of the assets exceeds the fair value of the assets. Fair value would be assessed using discounted cash flows or other appropriate measures of fair value. The Company has no t recognized any impairment losses for the years ended December 31, 2021, 2020, and 2019 .
Leases	Leases The Company adopted the Accounting Standard Update (“ASU”) 2016-02, Leases, and additional ASUs issued to clarify and update the guidance in ASU 2016-02 (collectively, “ASC 842”), as of January 1, 2021. See the section Recently Adopted Accounting Pronouncements below for more information. 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. The Company elected to use the transition relief package of practical expedients but did not elect to use the hindsight practical expedient in determining a lease term and impairment of ROU assets at the adoption date. For short-term leases, defined as leases with a term of twelve months or less, the Company elected the practical expedient to not recognize an associated lease liability and ROU asset. Lease payments for short-term leases are expensed on a straight-line basis over the lease term. The Company does not currently have any short-term leases. Operating leases are included in operating lease right-of-use assets, operating lease liabilities, and operating lease liabilities, non-current on the Company’s consolidated balance sheets. The Company does not have any finance leases.
Lease Accounting Prior to the Adoption of ASC 842	Lease Accounting Prior to the Adoption of ASC 842 For operating leases, the Company recorded rent expense using the straight-line method over the lease term, which includes the period of time from when the Company takes possession of the leased space until leasehold improvements are completed and the space is occupied. The difference between rent expense and amounts paid under the lease agreement is deferred in the accompanying consolidated balance sheets. Tenant improvement allowances and other lease incentives are recorded as liabilities and are amortized on the straight-line basis over the lease term as reductions to rent expense.
Beneficial Conversion Features	Beneficial Conversion Features A beneficial conversion feature is a non-detachable conversion feature that is “in the money” at the commitment date, which requires recognition of interest expense for underlying debt instruments and a deemed dividend for underlying equity instruments. A conversion option is “in the money” if the effective conversion price is lower than the commitment date fair value of the share into which it is convertible.
Accounting for Derivatives	Accounting for Derivatives The Company evaluates its convertible instruments and other contracts to determine if those contracts or embedded components of those contracts are required to be recognized under Accounting Standards Codification (“ASC”) Topic 815, Derivatives and Hedging . The result of this accounting treatment is that the derivative is carried at fair value as an asset or liability with changes in fair value recognized in earnings as they occur. Although separately measured at fair value, the fair value of bifurcated embedded derivatives is presented with the host contract in the consolidated balance sheets. Changes in the fair value of derivatives are recorded in the accompanying consolidated statements of operations and comprehensive loss as a component of other income (expense).
Revenue recognition	Revenue Recognition The Company recognizes revenue in a manner that depicts the transfer of control of a product or a service to a customer and reflects the amount of the consideration the Company is entitled to receive in exchange for such product or service. In doing so, the Company follows a five-step approach: (i) identify the contract with a customer, (ii) identify the performance obligations in the contract, (iii) determine the transaction price, (iv) allocate the transaction price to the performance obligations, and (v) recognize revenue when (or as) the customer obtains control of the product or service. The Company considers the terms of a contract and all relevant facts and circumstances when applying the revenue recognition standard. A customer is a party that has entered into a contract with the Company, where the purpose of the contract is to obtain a product or a service that is an output of the Company’s ordinary activities in exchange for consideration. To be considered a contract, (i) the contract must be approved (in writing, orally, or in accordance with other customary business practices), (ii) each party’s rights regarding the product or the service to be transferred can be identified, (iii) the payment terms for the product or the service to be transferred can be identified, (iv) the contract must have commercial substance (that is, the risk, timing or amount of future cash flows is expected to change as a result of the contract), and (v) it is probable that the Company will collect substantially all of the consideration to which it is entitled to receive in exchange for the transfer of the product or the service. A performance obligation is defined as a promise to transfer a product or a service to a customer. The Company identifies each promise to transfer a product or a service (or a bundle of products or services, or a series of products and services that are substantially the same and have the same pattern of transfer) that is distinct. A product or a service is distinct if both (i) the customer can benefit from the product or the service either on its own or together with other resources that are readily available to the customer and (ii) the Company’s promise to transfer the product or the service to the customer is separately identifiable from other promises in the contract. Each distinct promise to transfer a product or a service is a unit of accounting for revenue recognition. If a promise to transfer a product or a service is not separately identifiable from other promises in the contract, such promises should be combined into a single performance obligation. The transaction price is the amount of consideration the Company is entitled to receive in exchange for the transfer of control of a product or a service to a customer. To determine the transaction price, the Company considers the existence of any significant financing component, the effects of any variable elements, noncash consideration and consideration payable to the customer. If a significant financing component exists, the transaction price is adjusted for the time value of money. If an element of variability exists, the Company must estimate the consideration it expects to receive and uses that amount as the basis for recognizing revenue as the product or the service is transferred to the customer. There are two methods for determining the amount of variable consideration: (i) the expected value method, which is the sum of probability-weighted amounts in a range of possible consideration amounts, and (ii) the mostly likely amount method, which identifies the single most likely amount in a range of possible consideration amounts. If a contract has multiple performance obligations, the Company allocates the transaction price to each distinct performance obligation in an amount that reflects the consideration the Company is entitled to receive in exchange for satisfying each distinct performance obligation. For each distinct performance obligation, revenue is recognized when the Company transfers control of the product or the service applicable to such performance obligation. In those instances where the Company first receives consideration in advance of satisfying its performance obligation, the Company classifies such consideration as deferred revenue until (or as) the Company satisfies such performance obligation. In those instances where the Company first satisfies its performance obligation prior to its receipt of consideration, the consideration is recorded as accounts receivable. The Company expenses incremental costs of obtaining and fulfilling a contract as incurred if the expected amortization period of the asset that would be recognized is one year or less, or if the amount of the asset is immaterial. Otherwise, such costs are capitalized as contract assets if they are incremental to the contract and amortized to expense proportionate to revenue recognition of the underlying contract.
Research and development expenses	Research and Development Expenses The Company’s activities have largely consisted of research and development efforts related to developing our CAB programs. Research and development expenses consist of expenses incurred in performing research and development activities including salaries and benefits, facilities and other overhead expenses, clinical trials, contract services and other outside expenses. Research and development expenses are charged to expense as incurred. Payments for these activities are based on the terms of the individual agreements, which may differ from the pattern of costs incurred, and are reflected in the accompanying consolidated balance sheets as prepaid or accrued expenses. When evaluating the adequacy of the accrued expenses, the Company analyzes progress of the services, including the phase or completion of events, invoices received and contracted costs. Significant judgments and estimates may be made in determining the accrued balances at the end of any reporting period. Actual results could differ from the Company’s estimates. As of December 31, 2021, the Company has accrued $ 6.2 million related to clinical trial costs. The Company has entered into contracts related to its clinical trials with clinical research organizations. The Company reviews and accrues clinical trial costs based on work performed, which relies on estimates of total trial management costs, sites activated, patients enrolled, and number of patient visits. The Company follows this method since reasonably dependable estimates of the costs applicable to clinical trials can be made. Accrued clinical trial costs are subject to revisions as the trials progress. Revisions are charged to expense in the period in which the facts that give rise to the revision become known. Historically, revisions have not resulted in material changes to research and development expense; however, a modification in the protocol of a clinical trial or cancellation of a trial could result in a change to the Company's results of operations.
Patent costs	Patent Costs Costs related to filing and pursuing patent applications are recorded as general and administrative expenses and expensed as incurred since recoverability of such expenditures is uncertain.
Equity-based compensation related to profits interest plan	Equity-Based Compensation Related to Profits Interest Plan Prior to the Corporate Reorganization in July 2020, the Company had a profits interest plan that was a liability award plan in accordance with ASC Topic 718, Compensation – Stock Compensation (Topic 718) . The Company measured the fair value of each award on the grant date and recognized such fair value over the requisite service period (usually the vesting period) on a straight-line basis. The fair value of the award was remeasured at each reporting date until the award was settled, with a true-up of compensation cost for changes in fair value prorated for the portion of the requisite service period rendered. Once vested, any subsequent change in fair value was recognized immediately. The fair value of any awards that expired or were forfeited or canceled for no value was adjusted to zero, as they occurred, such that any previously recorded compensation cost would be fully reversed. Subsequent to the Corporate Reorganization and amendment of the profits interest plan by Himalaya Parent in October 2020, the Company no longer reflects compensation cost and a corresponding capital contribution associated with the ongoing mark-to-market of the Class B profits interests held by Himalaya Parent LLC.
Stock-based compensation	Stock-Based Compensation Stock-based compensation expense represents the grant date fair value of equity awards, consisting of stock options, restricted stock units (“RSUs”) and employee stock purchase plan rights, over the requisite service period of the awards (usually the vesting period) on a straight-line basis. The Company estimates the fair value of stock option grants and employee stock purchase plan rights using the Black-Scholes option pricing model. Prior to the Company’s IPO, the fair value of RSUs was based on the estimated fair value of the underlying common stock on the date of grant and, subsequent to the Company’s IPO, the fair value is based on the closing sales price of the Company’s common stock on the date of grant. Equity award forfeitures are recognized as they occur.
Income taxes	Income Taxes The Company accounts for income taxes under the asset and liability method, which requires the recognition of deferred tax assets and liabilities for the expected future tax consequences of events that have been included in the consolidated financial statements. Under this method, deferred tax assets and liabilities are determined based on the differences between the financial statements and tax basis of assets and liabilities using enacted tax rates in effect for the year in which the differences are expected to reverse. The effect of a change in tax rates on deferred tax assets and liabilities is recognized as income in the period that includes the enactment date. The Company recognizes net deferred tax assets to the extent that the Company believes these assets are more likely than not to be realized. In making such a determination, management considers all available positive and negative evidence, including future reversals of existing taxable temporary differences, projected future taxable income, exclusive of reversing temporary difference, tax-planning strategies, and the results of recent operations. If management determines that the Company would be able to realize its deferred tax assets in the future in excess of their net recorded amount, management would make an adjustment to the deferred tax asset valuation allowance, which would reduce the provision for income taxes. The Company records uncertain tax positions on the basis of a two-step process whereby (1) management determines whether it is more likely than not that the tax positions will be sustained on the basis of the technical merits of the position and (2) for those tax positions that meet the more-likely-than-not recognition threshold, management recognizes the largest amount of tax benefit that is more than 50 % likely to be realized upon ultimate settlement with the related tax authority. The Company recognizes interest and penalties related to unrecognized tax benefits within income tax expense. Any accrued interest and penalties are included within the related tax liability.
Comprehensive loss	Comprehensive Loss Comprehensive loss is defined as a change in equity during a period from transactions and other events and circumstances from non-owner sources. There have been no items qualifying as other comprehensive loss and, therefore, for all periods presented, the Company’s comprehensive loss was the same as its reported net loss.
Net loss per unit/share	Net Loss Per Unit/Share Prior to the Corporate Reorganization, the Company applied the two-class method for calculating and presenting net loss per unit. In applying the two-class method, earnings are hypothetically allocated between the common, preferred, and other participating securities based on their respective rights to receive non-forfeitable distributions, whether or not declared. The Company considered its Class A units to be its “common units” since Class A units were the most subordinate class of equity with respect to preference in liquidation. In addition, the Class C units were entitled to a preferred return equal to 10 % per annum, simple interest, on the Class C issuance price. The Company’s Class B units were excluded from the net loss per unit calculations based on the presumption that the units would be settled in cash pursuant to the terms of the Company’s operating agreement. Basic net loss per Class A unit was calculated by dividing net loss allocable to Class A unit holders (after adjustment for Class C preferred return and allocation of net losses to Class C units) by the weighted-average number of Class A units outstanding during the period. The Company calculated diluted net loss per unit using the more dilutive of 1) the treasury stock method, if-converted method, or contingently issuable share method, as applicable, or 2) the two-class method. For the year ended December 31, 2019, the basic and diluted net loss per unit were the same as the inclusion of outstanding warrants, convertible debt or Class C preferred units would be antidilutive. Subsequent to the Corporate Reorganization, basic net loss per 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 common stock warrants, RSUs, and common stock options outstanding under the Company’s stock option plan. For the year ended December 31, 2020, the Company determined that the attribution of pre-Corporate Reorganization net losses based on the post-Corporate Reorganization capital structure would not meaningfully represent the economic rights of the unit holders. As a result, the Company presents net loss per share information only for the period subsequent to the Corporate Reorganization. The basic and diluted net loss per share for the year ended December 31, 2020 represents only the period from July 10, 2020 to December 31, 2020, the period where the Company had outstanding common stock. The following table presents the calculation of basic and diluted net loss per share for the period following the Corporate Reorganization (in thousands, except share and per share data): July 10, 2020 Numerator: Net loss $ ( 26,877 ) Denominator: Weighted-average shares of common stock outstanding, basic and diluted 8,428,153 Net loss per common share, basic and diluted $ ( 3.19 ) Potentially dilutive securities not included in the calculation of diluted net loss per share because to do so would be anti-dilutive are as follows (in common stock equivalents): December 31, December 31, Common stock warrants 151,088 717,674 Common stock options 1,086,902 615,106 Restricted stock units 975,046 1,920,037 Total 2,213,036 3,252,817
Recent accounting pronouncements	Recent Accounting Pronouncements Under the Jumpstart Our Business Startups Act of 2012, or the JOBS Act, emerging growth companies (“EGC”) can delay adopting new or revised accounting standards issued subsequent to the enactment of the JOBS Act until such time as those standards apply to private companies. The Company elected to retain the ability to use this extended transition period for complying with new or revised accounting standards that have different effective dates for public and private companies until the earlier of the date that the Company (i) is no longer an emerging growth company or (ii) affirmatively and irrevocably opts out of the extended transition period provided in the JOBS Act. The Company lost its emerging growth company status on December 31, 2021 because the Company became a large accelerated filer due to the fact that the Company’s public float exceeded $700 million as of the June 30, 2021 measurement date. The Company adopted the following accounting standards during the year ended December 31, 2021: In February 2016, the Financial Accounting Standards Board (“FASB”) issued ASU No. 2016-02, Leases. The new standard establishes a right-of-use model and requires a lessee to recognize on the balance sheet a right-of-use asset and corresponding lease liability for all leases with terms longer than 12 months. Leases will be classified as either finance or operating, with classification affecting the pattern of expense recognition in the income statement. Effective January 1, 2021, the Company adopted this new standard prospectively using a modified retrospective transition approach. The Company elected the package of practical expedients permitted under the transition guidance of the new standard, which allowed the Company to carry forward its historical assessment on whether a contract is or contains a lease, lease classification, and initial direct costs. Upon adoption on January 1, 2021, the Company recognized operating lease ROU assets of $ 4.1 million, and current and non-current operating lease liabilities of $ 1.1 million and $ 5.4 million, respectively. The difference between the asset and liabilities is primarily attributable to adjustments to the right-of-use asset at transition related to lease incentives and deferred rent. The adoption of ASC 842 did not have a material impact to Company’s consolidated statements of operations and cash flows from operations. In December 2019, the FASB issued ASU No. 2019-12 Income Taxes (Topic 740) Simplifying the Accounting for Income Taxes. The Board issued this Update as part of its Simplification Initiative to improve areas of GAAP and reduce cost and complexity while maintaining usefulness. The main provisions remove certain exceptions including the exception to the general methodology for calculating income taxes in an interim period when a year-to-date loss exceeds the anticipated loss for the year. In addition, the amendments simplify income tax accounting in the areas such as income-based franchise taxes, eliminating the requirements to allocate consolidated current and deferred tax expense in certain instances, and a requirement that an entity reflects the effect of enacted changes in tax laws or rates in the annual effective tax rate computation in the interim period that includes the enactment date. For public companies, the standard is effective for fiscal years beginning after December 15, 2020 and interim periods therein. The Company adopted ASU 2019-12 on the effective date of January 1, 2021. The amendments were applied on a prospective basis and the adoption did not have a significant impact on the Company's financial results.

Organization and summary of s_3

Organization and summary of significant accounting policies (Tables)	12 Months Ended
	Dec. 31, 2021
Accounting Policies [Abstract]
Schedule of Earnings Per Share, Basic and Diluted	The following table presents the calculation of basic and diluted net loss per share for the period following the Corporate Reorganization (in thousands, except share and per share data): July 10, 2020 Numerator: Net loss $ ( 26,877 ) Denominator: Weighted-average shares of common stock outstanding, basic and diluted 8,428,153 Net loss per common share, basic and diluted $ ( 3.19 )
Schedule of Anti-dilutive Securities Excluded from Calculation of Diluted Net Loss Per Share	Potentially dilutive securities not included in the calculation of diluted net loss per share because to do so would be anti-dilutive are as follows (in common stock equivalents): December 31, December 31, Common stock warrants 151,088 717,674 Common stock options 1,086,902 615,106 Restricted stock units 975,046 1,920,037 Total 2,213,036 3,252,817

Balance sheet details (Tables)

Balance sheet details (Tables)	12 Months Ended
	Dec. 31, 2021
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, 2021 2020 Prepaid research and development $ 1,811 $ 2,004 Other prepaid expenses and current assets 502 72 Total $ 2,313 $ 2,076
Schedule of Property and Equipment	Property and equipment consist of the following (in thousands): December 31, Useful life (years) 2021 2020 Furniture, fixtures and office equipment 3 - 7 $ 2,123 $ 1,719 Laboratory equipment 5 2,123 1,790 Leasehold improvements 2 - 3 3,687 3,663 7,933 7,172 Less accumulated depreciation and amortization ( 4,257 ) ( 3,070 ) Total $ 3,676 $ 4,102
Schedule of Accounts Payable and Accrued Expenses	Accounts payable and accrued expenses consist of the following (in thousands): December 31, 2021 2020 Accounts payable $ 1,179 $ 2,456 Accrued compensation 2,671 2,804 Accrued research and development 13,501 4,852 Accrued equity issuance costs — 1,143 Other accrued expenses 1,073 813 Total $ 18,424 $ 12,068

Fair value measurements (Tables

Fair value measurements (Tables)	12 Months Ended
	Dec. 31, 2021
Fair Value Disclosures [Abstract]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation	The following table provides a reconciliation of the embedded derivative liability measured at fair value using Level 3 unobservable inputs (in thousands): Embedded Balance at December 31, 2019 $ 1,856 Initial fair value of embedded derivatives issued 3,415 Change in fair value 1,581 Settlement ( 6,852 ) Balance at December 31, 2020 $ —

Leases (Tables)

Leases (Tables)	12 Months Ended
	Dec. 31, 2021
Lessee Disclosure [Abstract]
Summary of Supplemental Balance Sheet Information Related to Lease Liabilities	Supplemental balance sheet information related to lease liabilities at December 31, 2021, was as follows (in thousands): Lease-Related Assets and Liabilities Financial Statement Line Items As of December 31, 2021 Right-of-use assets: Operating leases Operating lease right-of-use assets $ 3,300 Total right-of-use assets $ 3,300 Lease Liabilities: Operating leases Operating lease liabilities $ 1,389 Operating lease liabilities, noncurrent 3,982 Total lease liabilities $ 5,371
Components of Lease Expense	The components of lease expense included in the Company’s consolidated statements of operations include (in thousands): Year Ended Operating lease expense $ 1,043 Variable lease expense 512 Total lease expense, net $ 1,555
Summary of Weighted Average Remaining Lease Term and Weighted Average Discount Rate	The weighted average remaining lease term and weighted average discount rate for operating leases as of December 31, 2021 were as follows: Year Ended Weighted average remaining lease term (in years) 3.5 Weighted average discount rate percentage 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): Year Ended Cash paid for amounts included in the measurement of operating leases $ 1,374
Maturities of Operating Lease Liabilities	Maturities of operating lease liabilities as of December 31, 2021 were as follows (in thousands): Years ending December 31: Operating 2022 $ 1,555 2023 1,636 2024 1,685 2025 845 Thereafter — Total future lease payments 5,721 Less imputed interest ( 350 ) Total operating lease liabilities $ 5,371
Summary of Annual Minimum Payments Under Noncancelable Operating Leases	As of December 31, 2020, prior to the Company’s adoption of ASC 842, annual minimum payments under noncancelable operating leases were as follows (in thousands): Years ending December 31: Operating 2021 $ 1,374 2022 1,555 2023 1,636 2024 1,685 Thereafter 845 Total minimum lease payments $ 7,095

Convertible preferred stock a_2

Convertible preferred stock and members's/stockholders' equity (deficit) (Tables)	12 Months Ended
	Dec. 31, 2021
Equity [Abstract]
Schedule of Common Stock Warrants	As of December 31, 2021 the remaining common stock warrants below are exercisable and expire as follows: Outstanding and exercisable Exercise price per share Expiration date 151,088 $ 132.37 March 12, 2022
Schedule of Stock-Based Compensation Expense	Stock-based compensation expense recognized for all equity awards under the 2020 Plan has been reported in the consolidated statements of operations and comprehensive loss as follows (in thousands): Year ended Year ended Research and development $ 4,688 $ 740 General and administrative 20,429 2,282 Total $ 25,117 $ 3,022
Summary of Restricted Stock Units	The following table summarizes RSU activity under the 2020 Plan for the years ended December 31, 2021 and 2020: Number of Weighted - Outstanding at December 31, 2019 — $ — Granted 1,920,037 $ 18.00 Vested — $ — Outstanding at December 31, 2020 1,920,037 $ 18.00 Granted — $ — Vested 944,991 $ 18.00 Outstanding at December 31, 2021 975,046 $ 18.00
Summary of Stock Option Activity	The following table summarizes stock option activity under the 2020 Plan for the year ended December 31, 2021 and 2020 (in thousands, except share and per option data and years): Number of Weighted - Weighted - Aggregate Balance at December 31, 2019 — $ — — $ — Granted 615,106 $ 18.00 Balance at December 31, 2020 615,106 $ 18.00 9.95 $ 9,848 Granted 479,543 $ 37.86 Exercised ( 7,747 ) $ 18.00 — $ 182,829 Balance at December 31, 2021 1,086,902 $ 26.76 9.22 $ 991,495 Vested and expected to vest at December 31, 2021 1,086,902 $ 26.76 9.22 $ 991,495 Exercisable at December 31, 2021 155,579 $ 18.31 8.97 $ 247,486
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: Year ended Year ended Expected volatility 74.7 % 74.5 % Risk-free interest rate 1.06 % 0.52 % Expected dividend yield 0.0 % 0.0 % Expected term 5.98 years 6.09 years
Schedule of Common Stock Reserved for Future Issuance	Common stock reserved for future issuance are as follows in common equivalent shares: December 31, December 31, Warrants for the purchase of common stock 151,088 717,674 Common stock options and restricted stock units issued and outstanding 2,061,948 2,535,143 Awards available for future issuance under the 2020 Plan 3,211,854 2,404,535 Awards available for future issuance under the ESPP 822,811 464,829 Total common stock reserved for future issuance 6,247,701 6,122,181

Profits interest incentive pl_2

Profits interest incentive plan (Tables)	12 Months Ended
	Dec. 31, 2021
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Summary of Activity Under the plan	Activity under the Plan is summarized as follows: Outstanding at December 31, 2019 14,478,949 Cancelled ( 170,836 ) Assumption of Plan by Himalaya Parent LLC on July 10, 2020 ( 14,308,113 ) Outstanding at December 31, 2020 —
Schedule of Nonvested Share Activity	Vesting of Class B units under the Plan is summarized as follows: Unvested at December 31, 2019 6,158,328 Cancelled ( 170,836 ) Vested ( 1,310,807 ) Assumption of unvested Class B units by Himalaya Parent LLC on ( 4,676,685 ) Unvested at December 31, 2020 —
Schedule of Profit Interest Liability Reconciliation	The following table provides a reconciliation of the profits interest liability (in thousands): Balance at December 31, 2019 8,592 Decrease in fair value of vested liability (Pre-Corporate Reorganization) recognized as decrease to stock-based ( 7,601 ) Fair value of vested liability assumed by Himalaya Parent LLC on July 10, 2020 recognized as additional paid-in ( 991 ) Balance at December 31, 2020 $ —
Allocation of Equity Based Compensation for Class B units	The allocation of equity-based compensation, including $ 0.7 million from Himalaya Parent as a capital contribution during 2020, for all Class B units is as follows (in thousands): Years ended December 31, 2020 2019 Research and development $ ( 2,993 ) $ ( 2,997 ) General and administrative ( 3,859 ) ( 3,406 ) Total $ ( 6,852 ) $ ( 6,403 )

Income taxes (Tables)

Income taxes (Tables)	12 Months Ended
	Dec. 31, 2021
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): Year ended Year ended Tax computed at the federal statutory rate $ ( 20,034 ) $ ( 7,529 ) Deferred impact of conversion to C Corporation ( 2,131 ) ( 6,708 ) Partnership income not subject to tax — 1,837 Nondeductible executive compensation 4,145 — Stock-based compensation ( 1,021 ) — Research and development and orphan drug credits ( 3,091 ) ( 807 ) Uncertain tax positions 757 197 Other, net 793 242 Valuation allowance 20,582 12,768 Income tax expense $ — $ —
Schedule of Deferred Tax Assets and Liabilities	The Company’s net deferred tax assets (liabilities) are as follows (in thousands): December 31, December 31, Deferred tax assets: Net operating loss carryforwards $ 21,935 $ 5,607 Guaranteed payments — 1,702 Liability to licensor 4,159 — Deferred revenue — 4,159 Goodwill 3,449 — Deferred rent — 504 Lease liability 1,128 — Accrued compensation 485 585 Research credit carryforwards 2,945 610 Stock-based compensation 697 438 Other 2 0 Gross deferred tax assets 34,800 13,605 Less valuation allowance ( 33,351 ) ( 12,768 ) Total deferred tax assets 1,449 837 Deferred tax liabilities: Fixed assets ( 756 ) ( 837 ) Operating lease right-of-use asset ( 693 ) — Total deferred tax liabilities ( 1,449 ) ( 837 ) Net deferred tax assets $ — $ —
Schedule of Unrecognized Tax Benefits	The following table summarizes the reconciliation of the unrecognized tax benefits activity during the year ended December 31, 2021 (in thousands): Balance as of December 31, 2019 $ — Gross increase – current-period tax positions 210 Balance as of December 31, 2020 $ 210 Gross increase – current-period tax positions 801 Balance as of December 31, 2021 $ 1,011

Organization and summary of s_4

Organization and summary of significant accounting policies - Additional Information (Details)	Dec. 02, 2020	Jul. 31, 2020shares	Dec. 31, 2021USD ($)NumberOfSegmentshares	Dec. 31, 2020USD ($)shares	Dec. 31, 2019USD ($)	Jan. 01, 2021USD ($)	Jul. 13, 2020shares
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		6,220,050	35,799,233	32,171,560
Preferred Stock, Shares Issued | shares			0	0
Stockholders' Equity, Reverse Stock Split	1-for-13
Accumulated deficit | $			$ (186,319,000)	$ (90,917,000)
Uncertain tax positions percentage			50.00%
Number of operating segment | NumberOfSegment			1
Impairment losses | $			$ 0	0	$ 0
Preferred return percentage			10.00%
Operating lease right-of-use-assets | $			$ 3,300,000	0		$ 4,100,000
Operating lease liabilities | $			1,389,000	0		1,100,000
Operating lease liabilities, less current portion | $			3,982,000	$ 0		$ 5,400,000
Accrued clinical trial cost | $			$ 6,200,000
Customer Concentration Risk | Customer | Revenue Benchmark
Organization And Summary Of Significant Accounting Policies [Line Items]
Concentration Risk, Percentage			0.00%	100.00%	91.00%
Accumulated deficit
Organization And Summary Of Significant Accounting Policies [Line Items]
Accumulated deficit | $			$ 186,300,000
Class B Common Stock
Organization And Summary Of Significant Accounting Policies [Line Items]
Common unit, issued | shares			1,750,000
Common Stock, Shares, Issued | shares			1,492,059	1,492,059
Series D Convertible Preferred Stock
Organization And Summary Of Significant Accounting Policies [Line Items]
Common Stock, Shares, Issued | shares		59,164,808
Preferred Stock, Shares Issued | shares		59,164,808					140,626,711
Subsequent sale of convertible preferred stock to new investors, Shares | shares		140,626,711

Organization and summary of s_5

Organization and summary of significant accounting policies - Schedule of Earnings Per Share, Basic and Diluted (Details) - USD ($) $ / shares in Units, $ in Thousands	6 Months Ended	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2021		Dec. 31, 2020		Dec. 31, 2019
Numerator:
Net loss	$ (26,877)	$ (95,402)		$ (35,853)		$ (29,855)
Denominator:
Weighted-average shares of common stock outstanding, basic and diluted	8,428,153
Net loss per common share, basic and diluted	$ (3.19)	$ (2.76)	[1]	$ (3.19)	[1]
[1]	The net loss attributable to common stockholders and related per share amounts for the year ended December 31, 2020 are based on the period from July 10, 2020 to December 31, 2020, the period where the Company had outstanding common stock (see Note 1).

Organization and summary of s_6

Organization and summary of significant accounting policies - Schedule of Anti-dilutive Securities Excluded from Calculation of Diluted Net Loss Per Share (Details) - shares	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from calculation of diluted net loss per share	2,213,036	3,252,817
Common stock warrants
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from calculation of diluted net loss per share	151,088	717,674
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	1,086,902	615,106
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	975,046	1,920,037

Balance sheet details - Schedul

Balance sheet details - Schedule of Prepaid Expenses Other Current Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Balance Sheet Related Disclosures [Abstract]
Prepaid research and development	$ 1,811	$ 2,004
Other prepaid expenses and current assets	502	72
Total	$ 2,313	$ 2,076

Balance sheet details - Sched_2

Balance sheet details - Schedule of Property and Equipment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	$ 7,933	$ 7,172
Less accumulated depreciation and amortization	(4,257)	(3,070)
Total	3,676	4,102
Furniture Fixtures and Office Equipment
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	$ 2,123	1,719
Laboratory Equipment
Property Plant And Equipment [Line Items]
Property plant and equipment useful life	5 years
Property, plant and equipment, gross	$ 2,123	1,790
Leasehold Improvements
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	$ 3,687	$ 3,663
Minimum | Furniture Fixtures and Office Equipment
Property Plant And Equipment [Line Items]
Property plant and equipment useful life	3 years
Minimum | Leasehold Improvements
Property Plant And Equipment [Line Items]
Property plant and equipment useful life	2 years
Maximum | Furniture Fixtures and Office Equipment
Property Plant And Equipment [Line Items]
Property plant and equipment useful life	7 years
Maximum | Leasehold Improvements
Property Plant And Equipment [Line Items]
Property plant and equipment useful life	3 years

Balance sheet details - Sched_3

Balance sheet details - Schedule of Accounts Payable and Accrued Expenses (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Balance Sheet Related Disclosures [Abstract]
Accounts payable	$ 1,179	$ 2,456
Accrued compensation	2,671	2,804
Accrued research and development	13,501	4,852
Accrued equity issuance costs	0	1,143
Other accrued expenses	1,073	813
Total	$ 18,424	$ 12,068

Fair value measurements - Addit

Fair value measurements - Additional Information (Details) - USD ($)	Dec. 31, 2021	Dec. 31, 2020
Fair Value Disclosures [Abstract]
Assets measured at fair value	$ 0	$ 0
Liability measured at fair value	$ 0	$ 0

Fair value measurements - Fair

Fair value measurements - Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2020USD ($)
Fair Value Disclosures [Abstract]
Beginning Balance at December 31, 2019	$ 1,856
Initial fair value of embedded derivatives issued	3,415
Change in fair value	1,581
Settlement	(6,852)
Ending Balance at December 31, 2020	$ 0

Convertible and other debt - Ad

Convertible and other debt - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended			12 Months Ended
	Dec. 31, 2018	Apr. 30, 2018	Dec. 31, 2015	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Apr. 30, 2020	Aug. 31, 2018
Debt Instrument [Line Items]
interest expense				$ 3	$ 1,389	$ 1,630
Conversion price description		The 2018 Notes were amended in April 2020 to add a discount to the conversion prices such that they were convertible (i) automatically into preferred stock upon a qualified equity financing, with a conversion price of 80% of the lowest purchase price per share of preferred stock paid by investors in such qualified equity financing, (ii) automatically convert into common stock upon an initial public offering, with a conversion price of 80% of the price per share of common stock paid by investors in such initial public offering, and (iii) upon the election of each note holder, into Class C preferred units, with a conversion price per share of $2.7153136.				The 2019 Notes were convertible (i) automatically into preferred stock upon a qualified equity financing, with a conversion price of 80% of the lowest purchase price per share of preferred stock paid by investors in such qualified equity financing, (ii) automatically into common stock upon an initial public offering, with a conversion price of 80% of the price per share of common stock paid by investors in such initial public offering, and (iii) upon the election of each note holder, into Class C preferred units, with a conversion price per share of $2.7153136.
Gain (loss) on extinguishment of long-term debt				690	(2,883)	$ 0
Other Debt
Debt Instrument [Line Items]
Debt Instrument Outstanding Principal Amount					$ 700
Debt Instrument, Decrease, Forgiveness				700
Amendment and settlement of convertible notes (class D units)
Debt Instrument [Line Items]
Conversion price					$ 0.51554931	$ 0.412439448
Promissory notes payable to aggregate principal amount					$ 21,800
accrued interest					4,700
Convertible notes carrying value					$ 27,900
Amendment and settlement of convertible notes (class D units) | Himalaya Parent L L C
Debt Instrument [Line Items]
Gain (loss) on extinguishment of long-term debt				2,700
Issuance of Series D convertible preferred stock in connection with settlement of convertible promissory notes, shares					59,164,808
Convertible note issued				30,600
Pfizer Notes
Debt Instrument [Line Items]
Fee paid to lenders			$ 500
interest expense					$ 600	$ 1,000
Pfizer Notes | Pfizer Inc
Debt Instrument [Line Items]
Accrued interest rate			8.00%
Conversion price			$ 3.394142
Pfizer Notes | Pfizer Inc | Unsecured Convertible Promissory Note
Debt Instrument [Line Items]
Note issued			$ 10,000
2018 Notes
Debt Instrument [Line Items]
Note issued	$ 5,000
Accrued interest rate								8.00%
Conversion price							$ 2.7153136	$ 3.394142
Fee paid to lenders						200
interest expense					$ 400	$ 400
Gain (loss) on extinguishment of long-term debt				$ (200)
amortization of debt discounts	$ 2,200
2019 Notes
Debt Instrument [Line Items]
Accrued interest rate						8.00%
Conversion price					$ 0.86866	$ 2.7153136
interest expense					$ 300	$ 100
derivative liability						1,800
Promissory notes payable to aggregate principal amount						4,000
Due to related parties						1,500
Additional paid-in capital and debt discount						$ 500
outstanding principal balance							$ 2,500
2020 Notes
Debt Instrument [Line Items]
Accrued interest rate					8.00%
interest expense					$ 100
derivative liability					1,200
Promissory notes payable to aggregate principal amount					2,800
Due to related parties					$ 500
maturity dates					December 7, 2020
outstanding principal balance					$ 100
outstanding principal plus accrued interest divided					$ 0.86866

Leases - Additional Information

Leases - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Leases [Abstract]
Additional extended term	5 years
Lessor, operating lease, option to extend	The lease expires in July 2025 and the Company has an option to extend the term of the lease for an additional five years. However, it is not reasonably certain the Company will exercise the option to renew when the lease term ends and thus, the incremental term was excluded from the calculation of the lease liability. Additionally, the
Rent Expenses	$ 1.7	$ 1.1

Leases - Summary of Supplementa

Leases - Summary of Supplemental Balance Sheet Information Related to Lease Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Jan. 01, 2021	Dec. 31, 2020
Assets
Operating lease right-of-use-assets	$ 3,300	$ 4,100	$ 0
Total right-of-use assets	3,300
Lease Liabilities:
Operating lease liabilities	1,389	1,100	0
Operating lease liabilities, less current portion	3,982	$ 5,400	$ 0
Total lease liabilities	$ 5,371

Leases - Components of Lease Ex

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

Leases - Summary of Weighted Av

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

Leases - Supplemental Cash Flow

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

Leases - Maturities of Operatin

Leases - Maturities of Operating Lease Liabilities (Details) $ in Thousands	Dec. 31, 2021USD ($)
Leases [Abstract]
2022	$ 1,555
2023	1,636
2024	1,685
2025	845
Thereafter	0
Total future lease payments	5,721
Less imputed interest	(350)
Total operating lease liabilities	$ 5,371

Leases - Summary of Annual Mini

Leases - Summary of Annual Minimum Payments Under Noncancelable Operating Leases (Details) $ in Thousands	Dec. 31, 2020USD ($)
Leases [Abstract]
2021	$ 1,374
2022	1,555
2023	1,636
2024	1,685
Thereafter	845
Total minimum lease payments	$ 7,095

Convertible preferred stock a_3

Convertible preferred stock and members's/stockholders' equity (deficit) - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	Jan. 01, 2021	Jul. 13, 2020	Sep. 30, 2021	Jul. 31, 2020	Mar. 31, 2019	Dec. 31, 2018	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Class Of Stock [Line Items]
Preferred Stock Shares Issued							0	0
Payments to minority shareholders							$ 0	$ 19	$ 5
Proceeds From Issuance Of Convertible Preferred Stock							0	68,183	0
Proceeds from initial public offering, net of issuance costs							$ 0	$ 200,229	$ 0
Common Stock, Shares, Issued				6,220,050			35,799,233	32,171,560
Preferred Stock, Shares Authorized							200,000,000	200,000,000
Preferred Stock, Par or Stated Value Per Share							$ 0.0001	$ 0.0001
Common Stock, Shares Authorized							350,000,000	350,000,000
Common Stock, Par or Stated Value Per Share							$ 0.0001	$ 0.0001
Conversion of stock, description							Holders of the Company’s common stock have no conversion rights, while holders of the Company’s Class B common stock shall have the right to convert each share of Class B common stock into one share of common stock at such holder’s election, provided that as a result of such conversion, such holder would not beneficially own in excess of 4.99% of any class of the Company’s securities registered under the Securities Exchange Act of 1934
Period related to changing of ownership limitation percentage designated by Class B common stock holder							61 days
Warrants Expired And Unexercised							566,586
Annual rate of purchase price per share						7.00%
Net loss of HTKY allocated to noncontrolling interest								$ 61,000
Fair value of options, vested							$ 1,900
Vested								(1,310,807)
Total number of common shares reserved for issuance							6,247,701	6,122,181
Equity Option
Class Of Stock [Line Items]
Vested								0	0
Share-based Payment Arrangement, Nonvested Award, Option, Cost Not yet Recognized, Amount							$ 15,000
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition							3 years 1 month 6 days
Share Based Compensation Arrangement By Share Based Payment Award Options Grants In Period Weighted Average Grant Date Fair Value							$ 24.61	$ 11.66
Restricted Stock Units (RSUs)
Class Of Stock [Line Items]
Common Stock, Shares, Issued							2,061,948	2,535,143
Number of outstanding shares							975,046	1,920,037	0
Share-based Payment Arrangement, Nonvested Award, Option, Cost Not yet Recognized, Amount							$ 17,500
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition							2 years 2 months 12 days
Private Placement of Common Stock [Member]
Class Of Stock [Line Items]
Sale of stock price per share			$ 28
Common Stock, Shares, Issued			2,678,600
Proceeds from the Private Placement, net of underwriting discounts and commissions and other offering costs			$ 71,000
2020 Equity Incentive Plan [Member]
Class Of Stock [Line Items]
Common shares authorized for issuance							6,226,540	4,939,678
Shares available for awards, description	4
Vesting percentage							25.00%
Vesting period							36 months
Vesting terms, description							ten years
Employees Stock Purchase Plan [Member]
Class Of Stock [Line Items]
Common Stock, Shares, Issued							11,182
Common Stock, Shares Authorized							833,993	464,829
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 issuance of common stock							929,658
Total number of common shares reserved for issuance							822,811
Himalaya Therapeutics S E Z C
Class Of Stock [Line Items]
Purchase of ordinary shares					5,000,000	19,000,000
Payments to minority shareholders					$ 5,000	$ 19,000
IPO
Class Of Stock [Line Items]
Sale of stock issued in transaction								12,075,000
Sale of stock price per share								$ 18
Proceeds from initial public offering, net of issuance costs								$ 198,300
Vesting period							365 days
Vesting terms, description							The warrants became exercisable upon our IPO for a period of 365 and 450 days
Series D Convertible Preferred Stock
Class Of Stock [Line Items]
Preferred Stock Shares Issued		140,626,711		59,164,808
Subsequent sale of convertible preferred stock to new investors, Shares				140,626,711
Convertible preferred stock, per share		$ 0.51554931
Proceeds From Issuance Of Convertible Preferred Stock		$ 72,500
Convertible preferred stock, issuance costs		$ 4,300
Common Stock, Shares, Issued				59,164,808
Convertible Preferred Stock [Member] | IPO
Class Of Stock [Line Items]
Convertible Preferred Stock, Shares Issued upon Conversion								199,791,519
Common Stock, Shares, Issued								13,876,510
Class B Common Stock
Class Of Stock [Line Items]
Common Stock, Shares, Issued							1,492,059	1,492,059
Common Stock, Shares Authorized							15,368,569	15,368,569
Common Stock, Par or Stated Value Per Share							$ 0.0001	$ 0.0001
Vesting period							4 years
Class B Common Stock | IPO
Class Of Stock [Line Items]
Common Stock, Shares, Issued								1,492,059
Series B Convertible Preference Shares [Member]
Class Of Stock [Line Items]
Number of shares, held of outstanding HTKY preferred equity									97,183,256
Minimum per share amount of convertible preference shares liquation preference									$ 1
Common Stock
Class Of Stock [Line Items]
Common stock, voting rights							one
Number of shares, held of outstanding HTKY preferred equity									1,000

Convertible preferred stock a_4

Convertible preferred stock and members's/stockholders' equity (deficit) - Schedule of Common Stock Warrants (Details)	12 Months Ended
	Dec. 31, 2021$ / sharesshares
Class Of Stock [Line Items]
Exercise price per share	$ 18.31
March 12, 2022 [Member]
Class Of Stock [Line Items]
Outstanding and exercisable | shares	151,088
Exercise price per share	$ 132.37
Expiration date	Mar. 12, 2022

Convertible preferred stock a_5

Convertible preferred stock and members's/stockholders' equity (deficit) - Schedule of Stock-based Compensation Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Class Of Stock [Line Items]
Stock-based compensation	$ 25,117	$ 3,022	$ 0
Research and Development Expense
Class Of Stock [Line Items]
Stock-based compensation	4,688	740
General and Administrative Expense
Class Of Stock [Line Items]
Stock-based compensation	$ 20,429	$ 2,282

Convertible preferred stock a_6

Convertible preferred stock and members's/stockholders' equity (deficit) - Summary of Restricted Stock Units (Details) - Restricted Stock Units (RSUs) - $ / shares	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Class Of Stock [Line Items]
Number of Outstanding Shares, Beginning Balance	1,920,037	0
Number of Shares, Granted	0	1,920,037
Number of Shares, Vested	944,991	0
Number of Outstanding Shares, Ending Balance	975,046	1,920,037
Weighted Average Grant Date Fair Value, Beginning Balance	$ 18	$ 0
Weighted Average Grant Date Fair Value, Granted		18
Weighted Average Grant Date Fair Value, Vested	18	0
Weighted Average Grant Date Fair Value, Ending Balance	$ 18	$ 18

Convertible preferred stock a_7

Convertible preferred stock and members's/stockholders' equity (deficit) - Summary of Stock Option Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock Options Outstanding, Beginning Balance, Number of Shares	0	14,478,949
Granted, Number of Shares	479,543
Exercised, Number of Shares	(7,747)
Exercisable, Number of Shares	155,579
Stock Options Outstanding, Ending Balance, Number of Shares		0
Vested and expected to vest, Number of Shares	1,086,902
Granted, Weighted-Average Exercise Price per Share	$ 37.86
Exercise price per share	18.31
Share-based Compensation Arrangements by Share-based Payment Award, Options, Exercises in Period, Weighted Average Exercise Price	18
Outstanding, Ending Balance, Weighted-Average Exercise Price per Share | $ / shares	26.76
Vested and expected to vest, Weighted-Average Exercise Price per Share	$ 26.76
Outstanding, Weighted-Average Remaining Contractual Term (years)	9 years 2 months 19 days	9 years 11 months 12 days
Vested and expected to vest, Weighted-Average Remaining Contractual Term (years)	9 years 2 months 19 days
Exercisable, exercise price per share	$ 18.31
Exercisable, Weighted-Average Remaining Contractual Term (years)	8 years 11 months 19 days
Exercised, Aggregate intrinsic value	$ 182,829
Outstanding, Aggregate Intrinsic Value	991,495
Vested and expected to vest, Aggregate Intrinsic Value	991,495
Exercisable, Aggregate Intrinsic	$ 247,486
Equity Option
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock Options Outstanding, Beginning Balance, Number of Shares	615,106	0
Granted, Number of Shares		615,106
Stock Options Outstanding, Ending Balance, Number of Shares	1,086,902	615,106
Outstanding, Beginning Balance, Weighted-Average Exercise Price per Share	$ 18	$ 0
Granted, Weighted-Average Exercise Price per Share		18
Outstanding, Ending Balance, Weighted-Average Exercise Price per Share | $ / shares		$ 18
Outstanding, Aggregate Intrinsic Value	$ 9,848	$ 0
Outstanding, Aggregate Intrinsic Value		$ 9,848

Convertible preferred stock a_8

Convertible preferred stock and members's/stockholders' equity (deficit) - Summary of Assumptions Used in Black-Scholes Model (Details)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Stockholders Equity Note [Abstract]
Expected volatility	74.70%	74.50%
Risk-free interest rate	1.06%	0.52%
Expected dividend yield	0.00%	0.00%
Expected term	5 years 11 months 23 days	6 years 1 month 2 days

Convertible preferred stock a_9

Convertible preferred stock and members's/stockholders' equity (deficit) - Schedule of Common Stock Reserved for Future Issuance (Details) - shares	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Jul. 31, 2020
Class Of Stock [Line Items]
Common Stock, Shares, Issued	35,799,233	32,171,560	6,220,050
Common Stock, Shares, Outstanding	35,799,233	32,171,560
Total number of common shares reserved for issuance	6,247,701	6,122,181
Warrants [Member]
Class Of Stock [Line Items]
Warrants for the purchase of common stock	151,088	717,674
Restricted Stock Units (RSUs)
Class Of Stock [Line Items]
Common Stock, Shares, Issued	2,061,948	2,535,143
Common Stock, Shares, Outstanding	2,061,948	2,535,143
2020 Plan [Member]
Class Of Stock [Line Items]
Awards	3,211,854	2,404,535
Employees Stock Purchase Plan [Member]
Class Of Stock [Line Items]
Common Stock, Shares, Issued	11,182
Awards	822,811	464,829
Total number of common shares reserved for issuance	822,811

Profits interest incentive pl_3

Profits interest incentive plan - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Fair value of vested Class B units assumed by BioAtla Holdings and Inversagen		$ (991,000)
Share-based payment arrangement, expense		(6,852,000)	$ (6,403,000)
Reduction to aggregate profits interest liability as part of LLC Division			(900,000)
Increase (decrease) in profits interest liability			(7,400,000)
Class B Common Stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Fair Value Of Vested Liability Assumed by Himalaya Parent LLC		1,000,000
Fair value of vested Class B units assumed by BioAtla Holdings and Inversagen			800,000
Stock-based compensation expense and additional paid-in capital related to fair value of unvested liability			$ 200,000
Class B Units reserved for issuance			16,665,977
Share-based payment arrangement, expense		$ 700,000
Vesting period	4 years

Profits interest incentive pl_4

Profits interest incentive plan - Summary of Activity Under the Plan (Details)	12 Months Ended
	Dec. 31, 2020shares
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock Options Outstanding, Beginning Balance, Number of Shares	14,478,949
Cancelled	(170,836)
Assumption of Plan by Himalaya Parent LLC on July 10, 2020	(14,308,113)
Stock Options Outstanding, Ending Balance, Number of Shares	0

Profits interest incentive pl_5

Profits interest incentive plan - Schedule of Nonvested Share Activity (Details)	12 Months Ended
	Dec. 31, 2020shares
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Unvested at December 31, 2019	6,158,328
Cancelled	(170,836)
Vested	(1,310,807)
Assumption of unvested Class B units by Himalaya Parent LLC on July 10, 2020	(4,676,685)
Unvested at December 31, 2020	0

Profits interest incentive pl_6

Profits interest incentive plan - Schedule of Profit Interest Liability Reconciliation (Details)	12 Months Ended
	Dec. 31, 2020USD ($)
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Balance at December 31, 2019	$ 8,592,000
Decrease in fair value of vested liability (Pre-Corporate Reorganization) recognized as decrease to stock-based compensation expense	(7,601,000)
Fair value of vested liability assumed additional paid in capital	(991,000)
Balance at December 31, 2020	$ 0

Profits interest incentive pl_7

Profits interest incentive plan - Allocation of Equity-based Compensation For All Class B Units (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based payment arrangement, expense	$ (6,852)	$ (6,403)
Research and Development Expense
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based payment arrangement, expense	(2,993)	(2,997)
General and Administrative Expense
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based payment arrangement, expense	(3,859)	$ (3,406)
Class B Common Stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based payment arrangement, expense	$ 700

Collaboration, license and op_2

Collaboration, license and option agreements - Additional Information (Details) - USD ($) $ in Thousands	Nov. 18, 2021	Dec. 31, 2015	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Collaboration Amendment Date			2019-12
Upfront Non-Refundable Payment					$ 20,000
Transaction Price Of The Agreement					25,000
Revenues			$ 300
Current portion of deferred revenue			0	$ 19,806
Liability to licensor			$ 19,806	0
BeiGene
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Collaboration Amendment Date			2020-10
Reimbursement Of Manufacturing Costs					5,000
Revenues			$ 0	400	5,200
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			$ 19,800
Liability to licensor			$ 19,800
Pfizer Inc
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Revenues					$ 500
License and option agreement payment		$ 1,000
Collaboration agreement end date			2019-12
Collaboration agreement duration			4 years

Related party transactions - Ad

Related party transactions - Additional Information (Details) - USD ($)	Mar. 18, 2021	Jul. 07, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Jul. 31, 2020	Jan. 01, 2020
Related Party Transaction [Line Items]
Research and development expense			$ 58,274,000	$ 19,933,000	$ 25,919,000
Related party transaction, terms and manner of settlement			On March 18, 2021, the Company and Carolyn Anderson Short, its co-founder and former Chief of Intellectual Property & Strategy, mutually agreed that Ms. Short would depart the Company on May 31, 2021 following an agreed upon transition period. The Transition Agreement provides for the following severance benefits in exchange for a release of claims by Ms. Short: (i) a lump sum payment equal to eighteen (18) months of Ms. Short’s current base salary, (ii) a payment at her targeted bonus rate for 2021, pro-rated to the separation date, and (iii) accelerated full vesting of her equity awards including 7,747 stock options and 138,461 restricted stock units. The modification of these equity awards resulted in an incremental fair value of $7.0 million which was recognized on a straight-line basis over the transition service period. For the twelve months ended December 31, 2021, the Company recognized $1.0 million related to the lump sum salary payment and target bonus. The Company also recognized non-cash stock-based compensation charges of $9.4 million related to the modified equity awards for the twelve months ended December 31, 2021. No unrecognized stock-based compensation remained as of December 31, 2021. Ms. Short exercised her 7,747 stock options in 2021, therefore there are no remaining options outstanding related to Ms. Short’s transition agreement as of December 31, 2021.
Non-cash stock-based compensation charges			$ 25,117,000	3,022,000	0
Share-based payment arrangement, expense				$ (6,852,000)	$ (6,403,000)
Common Stock, Shares, Issued			35,799,233	32,171,560		6,220,050
Exercised, Number of Shares			7,747
Remaining Options outstanding number				0	14,478,949
E X U M A Biotech Corp And Subsidiary
Related Party Transaction [Line Items]
Share-based payment arrangement, expense					$ 15,000
Expense related To license agreement					10,000
Carolyn Anderson Short
Related Party Transaction [Line Items]
Number of accelerated full vesting equity awards including stock options	7,747
Number of accelerated full vesting equity awards including restricted stock units	138,461
Incremental Fair Value			$ 7,000,000
Expense related to Lump Sum Salary Payment and Target Bonus			1,000,000
Non-cash stock-based compensation charges			9,400,000
Unrecognized stock-based compensation			$ 0
Exercised, Number of Shares			7,747
Remaining Options outstanding number			0
Private Placement of Common Stock
Related Party Transaction [Line Items]
Common Stock, Shares, Issued			625,000
Net proceeds Issuance Of private placement			$ 17,500,000
Bio Duro
Related Party Transaction [Line Items]
Research and development expense					1,900,000
Biotech Investment Group II LLC
Related Party Transaction [Line Items]
Interest expense, related party				$ 42,000	20,000
Loan amount under the terms					500,000
Jay Short And Carolyn Anderson Short
Related Party Transaction [Line Items]
Debt instrument settled date			2020-07
Jay Short And Carolyn Anderson Short | 2019 Notes
Related Party Transaction [Line Items]
Debt instrument, face amount			$ 1,000,000
Interest expense, related party				100,000
Jay Short And Carolyn Anderson Short | 2020 Notes
Related Party Transaction [Line Items]
Debt instrument, face amount			$ 500,000
Interest expense, related party					$ 32,000
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]
Royalty Expense			0
Assets or liabilities associated with related party variable interest				0
Bio Atla Holdings L L C
Related Party Transaction [Line Items]
Assets or liabilities associated with related party variable interest			0	0
Options grants related to royalty payments, Period		10 years
Equity Interest In Related Party							50.00%
Himalaya Parent L L C
Related Party Transaction [Line Items]
Non-cash stock-based compensation charges			$ 0	$ 700,000

401(k) plan - Additional Inform

401(k) plan - Additional Information (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2021USD ($)
Compensation And Retirement Disclosure [Abstract]
Contributions made by company	$ 0

EXUMA Biotech Corp. - Additiona

EXUMA Biotech Corp. - Additional Information (Details) - USD ($)	1 Months Ended	12 Months Ended
	Nov. 30, 2019	Dec. 31, 2019
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
License Fee	$ 10,000
Sale of Equity Interest in Exuma	$ 25,000
Equity Method Investments [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Carrying Value of investment		$ 0
Cost-method Investments [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Carrying Value of investment		$ 0

Income taxes - Schedule of Inco

Income taxes - Schedule of Income Tax Reconciliation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Tax computed at the federal statutory rate	$ (20,034)	$ (7,529)
Deferred impact of conversion to C Corporation	(2,131)	(6,708)
Partnership income not subject to tax		1,837
Nondeductible executive compensation	4,145
Stock-based compensation	(1,021)
Research and development and orphan drug credits	(3,091)	(807)
Uncertain tax positions	757	197
Other, net	793	242
Valuation allowance	20,582	12,768
Income tax expense	$ 0	$ 0

Income taxes - Schedule of Defe

Income taxes - Schedule of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Deferred tax assets:
Net operating loss carryforwards	$ 21,935	$ 5,607
Guaranteed payments		1,702
Liability to licensor	4,159
Deferred revenue		4,159
Goodwill	3,449
Deferred rent		504
Lease liability	1,128
Accrued compensation	485	585
Research credit carryforwards	2,945	610
Stock-based compensation	697	438
Other	2	0
Gross deferred tax assets	34,800	13,605
Less valuation allowance	(33,351)	(12,768)
Total deferred tax assets	1,449	837
Deferred tax liabilities:
Fixed assets	(756)	(837)
Operating lease right-of-use asset	(693)
Total deferred tax liabilities	(1,449)	(837)
Net deferred tax assets	$ 0	$ 0

Income taxes - Additional Infor

Income taxes - Additional Information (Details) - USD ($) $ in Thousands	Mar. 27, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Operating Loss Carryforwards [Line Items]
Deferred tax asset valuation allowance		$ 33,351	$ 12,768
Change in Valuation Allowance		20,600
Federal net operating loss carryforward		$ 104,500
Tax credit limitation on use		The federal net operating losses can be carried forward indefinitely, subject to an 80% limitation against taxable income.
Use of annual operating loss carryforwards		Sections 382 and 383, annual use of the Company’s net operating loss carryforwards may be limited in the event a cumulative change in ownership of more than 50% occurs within a three-year period.
CARES Act NOL carryover/carryback offset to taxable income.	100.00%	50.00%
Unrecognized tax benefits		$ 1,011	$ 210	$ 0
PPP Loan
Operating Loss Carryforwards [Line Items]
Proceeds from loans		700
Domestic Tax Authority
Operating Loss Carryforwards [Line Items]
Orphan Drug Credit		$ 1,000
Operating Loss Carryforwards Expiration Period		2040
orphan drug credit carryforwards Expiration Period		2041
Domestic Tax Authority | Research and Development Tax Credit
Operating Loss Carryforwards [Line Items]
Tax Credit Carryforward, Amount		$ 1,900
California Franchise Tax Board | Research and Development Tax Credit
Operating Loss Carryforwards [Line Items]
Tax Credit Carryforward, Amount		$ 1,200

Income taxes - Schedule of Unre

Income taxes - Schedule of Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Beginning Balance	$ 210	$ 0
Gross increase – current-period tax positions	801	210
Ending Balance	$ 1,011	$ 210

Subsequent events - Additional

Subsequent events - Additional Information (Details)	Jan. 05, 2022
Subsequent Event
Subsequent Event [Line Items]
Description of clinical trial Agreement	BioAtla and Bristol-Myers Squibb Company (“BMS”) entered into a clinical trial collaboration and supply agreement (the “BMS Agreement”). Under the terms of the BMS Agreement, BioAtla and BMS will collaborate on clinical trials of separate combination therapies using two of BioAtla’s Conditionally Active Biologic Antibody Drug Conjugates, BA3011 and BA3021, each in combination with Opdivo® (nivolumab), BMS’ proprietary anti-PD-1 monoclonal antibody product. The Company will serve as the study sponsor of the scheduled studies and will be responsible for costs associated with the trial execution. BMS will provide Opdivo® clinical drug supply at no cost for the combination study trials. After the completion of the combination therapy trials, the Company is obligated to provide BMS with a final report of the data resulting from the trial. There was no impact to the Company's financial results for the year ended December 31, 2021 as a result of this agreement.