Pyxis Oncology (PYXS) 10-K 21 Mar 24 2023 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Mar. 20, 2024	Jun. 30, 2023
Cover [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2023
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	FY
Document Transition Report	false
Document Annual Report	true
Entity Registrant Name	Pyxis Oncology, Inc.
Entity Central Index Key	0001782223
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	true
ICFR Auditor Attestation Flag	false
Entity Shell Company	false
Entity Well-known Seasoned Issuer	No
Document Financial Statement Error Correction [Flag]	false
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity File Number	001-40881
Entity Tax Identification Number	83-1160910
Entity Address, Address Line One	321 Harrison Avenue
Entity Address, City or Town	Boston
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	02118
Entity Incorporation, State or Country Code	DE
City Area Code	617
Local Phone Number	221-9059
Title of 12(b) Security	Common Stock, par value $0.001 per share
Trading Symbol	PYXS
Security Exchange Name	NASDAQ
Entity Public Float			$ 97
Entity Common Stock, Shares Outstanding		58,133,375
Auditor Name	Ernst & Young LLP
Auditor Firm ID	42
Auditor Location	Boston, Massachusetts
Documents Incorporated by Reference	DOCUMENTS INCORPORATED BY REFERENCE None.

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Current assets:
Cash and cash equivalents	$ 9,664	$ 179,293
Marketable debt securities, short-term	109,634
Restricted cash	1,472	1,472
Prepaid expenses and other current assets	3,834	5,847
Total current assets	124,604	186,612
Property and equipment, net	11,872	11,165
Intangible assets, net	24,308
Operating lease right-of-use assets	12,942	13,602
Total assets	173,726	211,379
Current liabilities:
Accounts payable	3,896	7,097
Accrued expenses and other current liabilities	12,971	24,537
Operating lease liabilities, current portion	1,232
Deferred revenue	7,660
Total current liabilities	25,759	31,634
Operating lease liabilities, net of current portion	20,099	18,921
Deferred tax liability, net	2,164
Total liabilities	48,022	50,555
Commitments and contingencies (Note 19)
Stockholders' equity:
Preferred stock, par value $0.001 per share, 10,000,000 shares authorized; zero shares issued and outstanding
Common stock, $0.001 par value per share; 190,000,000 shares authorized; 44,754,853 and 35,110,016 shares issued as of December 31, 2023 and 2022, respectively, 44,754,853 and 34,958,730 shares outstanding as of December 31, 2023 and 2022, respectively	45	34
Additional paid-in capital	411,821	373,225
Accumulated other comprehensive income	63
Accumulated deficit	(286,225)	(212,435)
Total stockholders' equity	125,704	160,824
Total liabilities and stockholders' equity	$ 173,726	$ 211,379

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2023	Dec. 31, 2022
Preferred stock, par or stated value per share	$ 0.001	$ 0.001
Preferred stock, shares authorized	10,000,000	10,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value per share	$ 0.001	$ 0.001
Common stock, shares authorized	190,000,000	190,000,000
Common stock, shares issued	44,754,853	35,110,016
Common stock, shares outstanding	44,754,853	34,958,730

Consolidated Statements of Oper

Consolidated Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Operating expenses:
Research and development expense	$ 49,586	$ 86,129
General and administrative	32,610	37,352
Total operating expenses	82,196	123,481
Loss from operations	(82,196)	(123,481)
Other income, net:
Interest and investment income	6,630	2,764
Sublease income	1,776
Total other income, net	8,406	2,764
Net loss	$ (73,790)	$ (120,717)
Net loss per common share - basic	$ (1.85)	$ (3.65)
Net loss per common share - diluted	$ (1.85)	$ (3.65)
Weighted average shares of common stock outstanding - basic	39,904,603	33,033,081
Weighted average shares of common stock outstanding - diluted	39,904,603	33,033,081
Other comprehensive income:
Net unrealized gain on marketable debt securities	$ 63
Other comprehensive income	63
Comprehensive loss	$ (73,727)	$ (120,717)

Consolidated Statements of Conv

Consolidated Statements of Convertible Preferred Stock and Stockholders' Equity - USD ($) $ in Thousands	Total	Apexigen, Inc.	Pfizer License Agreement	ESPP	Common Stock	Common Stock Apexigen, Inc.	Common Stock Pfizer License Agreement	Common Stock ESPP	Additional Paid-in Capital	Additional Paid-in Capital Apexigen, Inc.	Additional Paid-in Capital Pfizer License Agreement	Additional Paid-in Capital ESPP	Accumulated Other Comprehensive Income	Accumulated Deficit
Beginning balance at Dec. 31, 2021	$ 261,313				$ 32				$ 352,999					$ (91,718)
Beginning Balance, Shares at Dec. 31, 2021					32,222,881
Issuance of common stock	4,281				$ 2				4,279
Issuance of common stock (Shares)					2,229,654
Stock options exercised	183								183
Stock options exercised (Shares)					73,841
Issuance of restricted common stock, net of tax withholdings (Shares)					432,354
Stock-based compensation	15,764								15,764
Net loss	(120,717)													(120,717)
Ending balance at Dec. 31, 2022	160,824				$ 34				373,225					(212,435)
Ending balance (in shares) at Dec. 31, 2022					34,958,730
Issuance of common stock		$ 10,732	$ 5,000	$ 132		$ 4	$ 2			$ 10,728	$ 4,998	$ 132
Issuance of common stock (Shares)						4,344,435	1,811,594	79,350
Shares issued pursuant to at-the-market ("ATM") program, net of commission	6,122				$ 1				6,121
Shares issued pursuant to at-the-market ("ATM") program, net of commission (shares)					1,001,208
Stock options exercised	$ 120								120
Stock options exercised (Shares)	83,235				83,235
Issuance of restricted common stock, net of tax withholdings	$ (445)				$ 4				(449)
Issuance of restricted common stock, net of tax withholdings (Shares)					2,476,301
Stock-based compensation	16,946								16,946
Net unrealized gain on marketable debt securities	63												$ 63
Net loss	(73,790)													(73,790)
Ending balance at Dec. 31, 2023	$ 125,704				$ 45				$ 411,821				$ 63	$ (286,225)
Ending balance (in shares) at Dec. 31, 2023					44,754,853

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Operating activities
Net loss	$ (73,790)	$ (120,717)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	1,927	709
Stock-based compensation	16,946	15,764
Non-cash research and development expenses		9,281
Non-cash lease expense	660	1,127
Accretion of discount on marketable debt securities	(4,788)
Changes in operating assets and liabilities:
Prepaid expenses and other assets	2,532	(3,381)
Accounts payable	(3,507)	(8,328)
Accrued expenses and other current liabilities	(14,097)	11,951
Operating lease liabilities	2,410	4,259
Deferred revenue	998
Net cash used in operating activities	(70,709)	(89,335)
Investing activities
Cash acquired in acquisition of Apexigen, Inc.	6,660
Redemption of marketable debt securities	92,048
Purchase of marketable debt securities	(196,831)
Purchase of property and equipment	(6,726)	(6,399)
Net cash used in investing activities	(104,849)	(6,399)
Financing activities
Proceeds from shares issued under ATM, net of commission	6,122
Tax withholding payments related to net settlement of restricted common stock	(445)
Proceeds from the exercise of stock options	120	183
Proceeds from the sale of stock under employee stock purchase plan	132
Net cash provided by financing activities	5,929	183
Net decrease in cash, cash equivalents, and restricted cash	(169,629)	(95,551)
Cash, cash equivalents and restricted cash at beginning of year	180,765	276,316
Cash, cash equivalents and restricted cash at end of period	11,136	180,765
Supplemental cash flow information:
Cash received for interest	2,419	2,166
Cash paid for taxes	48	17
Noncash operating, investing and financing activities:
Shares, warrants, and replacement stock options and restricted stock units issued for acquisition of Apexigen, Inc.	10,732
Property and equipment in accounts payable and accrued expenses	237	4,479
Operating lease right-of-use assets obtained in exchange for operating lease liabilities		14,497
Reconciliation of cash, cash equivalents and restricted cash:
Cash and cash equivalents	9,664	179,293
Restricted cash	1,472	1,472
Total cash, cash equivalents and restricted cash shown in the statement of cash flows	11,136	$ 180,765
Pfizer License Agreement
Noncash operating, investing and financing activities:
Issuance of common stock to Pfizer Inc.	$ 5,000

Description of Business

Description of Business	12 Months Ended
	Dec. 31, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Description of Business	1. Description of Business Nature of Business Pyxis Oncology, Inc. (the “Company”), a Delaware corporation, was founded in June 2018 and launched its operations in July 2019. The Company is a clinical stage company focused on defeating difficult-to-treat cancers. The Company is efficiently building next-generation therapeutics that hold the potential for mono and combination therapies. The Company's therapeutic candidates are designed to kill tumor cells and to address the underlying pathologies created by cancer that enable its uncontrollable proliferation and immune evasion. The Company's antibody-drug conjugates (“ADCs”) and immuno-oncology (“IO”) programs employ novel and emerging strategies to target a broad range of solid tumors resistant to current standards of care. The Company has one operating segment. The Company’s chief operating decision maker, its Chief Executive Officer, manages the Company’s operations on a consolidated basis for the purposes of assessing performance and allocating resources.

Basis of Presentation and Summa

Basis of Presentation and Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2023
Accounting Policies [Abstract]
Basis of Presentation and Summary of Significant Accounting Policies	2. Basis of Presentation and Summary of Significant Accounting Policies Basis of Presentation The Company’s fiscal year ends on December 31 and its first three quarters end on March 31, June 30 and September 30. The accompanying consolidated financial statements are prepared in conformity with accounting principles generally accepted in the United States of America (“GAAP”). Any reference in these notes to applicable guidance is meant to refer to the authoritative GAAP as found in the Accounting Standards Codification (“ASC”) and Accounting Standards Updates (“ASU”) of the Financial Accounting Standards Board (“FASB”). The consolidated financial statements include the Company and its wholly-owned subsidiaries. All intercompany balances and transactions have been eliminated upon consolidation. The Company is an “emerging growth company,” as defined in the Jumpstart Our Business Startups Act of 2012 (the “JOBS Act”). Section 107(b) of the JOBS Act provides that an emerging growth company can take advantage of an extended transition period for complying with new or revised accounting standards. Thus, an emerging growth company can delay the adoption of certain accounting standards until those standards would otherwise apply to private companies. The Company has irrevocably elected not to avail itself of this extended transition period, and, as a result, the Company will adopt new or revised accounting standards on the relevant dates on which adoption of such standards is required for other public companies. Liquidity As of December 31, 2023, the Company had an accumulated deficit of $ 286.2 million. The Company has incurred losses and negative cash flows from operations since inception, including net losses of $ 73.8 million and $ 120.7 million for the years ended December 31, 2023 and 2022, respectively. The Company has not generated any revenues from product sales to date and does not anticipate generating any revenues from product sales unless and until it successfully completes development and obtains regulatory approval for its current or any future product candidates. The Company expects that its operating losses and negative cash flows will continue for the foreseeable future as the Company continues to expand its research and development programs and develop its product candidates. The Company currently expects that its existing cash, cash equivalents and short-term investments of $ 119.3 million as of December 31, 2023 will fund its operating expenses and capital requirements at least twelve months from the date these audited consolidated financial statements are issued. Additional funding may be necessary to fund future clinical and preclinical activities. The Company plans to continue to fund its losses from operations and capital funding needs through public or private equity, convertible or debt financing 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. Use of Estimates The preparation of consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, expense, and related disclosures. The Company regularly evaluates estimates and assumptions related to assets, liabilities, stock-based compensation, operating leases, assessment of the useful lives of property and equipment, marketable debt securities, fair value of intangible assets and research and development costs, including clinical trial accruals. The Company bases its estimates and assumptions on historical experience and on various other factors that it believes to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities that are not readily apparent from other sources. Actual results could differ from those estimates and there may be changes to management’s estimates in future periods. Risks and Uncertainties The Company is subject to risks common to early-stage companies in the biopharmaceutical industry including, but not limited to, uncertainties related to commercialization of products, regulatory approvals, dependence on key suppliers for active ingredients and third-party service providers such as contract development and manufacturing organizations (“CDMOs”), protection of intellectual property rights and the ability to make milestone, royalty or other payments due under any license, collaboration or supply agreements. Concentration of Credit Risks Financial instruments which potentially subject the Company to significant concentration of credit risk consist of cash and cash equivalents, restricted cash and short-term investments. The Company invests its excess cash primarily in money market funds and highly liquid U.S. Treasury securities. The Company has adopted an investment policy that includes guidelines relative to credit quality, diversification and maturities to preserve principal and liquidity. Cash and Cash Equivalents The Company considers all short term, highly liquid investments with original maturities of 90 days or less to be cash equivalents. Cash equivalents consist primarily of money market funds as of December 31, 2023 and 2022. Investments Short-term investments consist of U.S. Treasury securities with original maturities greater than three months. The Company may sell investments at any time for use in current operations even if the investments have not yet reached maturity. As a result, the Company classifies its investments as current assets. All investments have been classified as available-for-sale marketable debt securities. Marketable debt securities are recorded at fair value, with unrealized gains and losses, net of tax, included as a component of accumulated other comprehensive income (loss) in stockholders’ equity and a component of total comprehensive loss in the consolidated statements of operations and comprehensive loss, until realized. The fair value of these securities is determined based upon quoted market prices at period end. Premiums paid or discounts received at the time of purchase of marketable securities, are amortized to interest and investment income over the terms of the related securities. Realized gains and losses are included in earnings and are derived using the specific identification method for determining the cost of securities sold. At each reporting date the Company will evaluate available-for-sale marketable debt securities in an unrealized loss position, using the discounted cash flow model, to determine whether the unrealized loss or any potential credit losses should be recognized in net loss. For available-for-sale marketable debt securities in an unrealized loss position, the Company will assess (i) whether it intends to sell, or (ii) it is more likely than not that it will be required to sell the security before recovery of its amortized cost basis. If the aforementioned criteria is met, such marketable debt security’s amortized cost basis will be written down to its fair value through earnings along with any existing allowance for credit losses. For available-for-sale marketable debt securities that do not meet this criteria, the Company will evaluate whether the decline in fair value has resulted from credit losses or other factors. In making this assessment, the Company considers the severity of the impairment, any changes in interest rates, underlying credit ratings, and forecasted recovery, among other factors. The credit-related portion of unrealized losses, and any subsequent improvements, are recorded as an allowance in interest income. There have been no impairment or credit losses recognized during the periods presented in the accompanying consolidated statements of operations and comprehensive loss. Fair Value Measurements Certain assets and liabilities are carried at fair value under GAAP. Fair value is defined as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principle or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. Valuation techniques used to measure fair value must maximize the use of observable inputs and minimize the use of unobservable inputs. Financial assets and liabilities carried at fair value are to be classified and disclosed in one of the following three levels of the fair value hierarchy, the first two are considered observable and the last is considered unobservable: Level 1 —Unadjusted quoted prices in active markets that are accessible at the measurement date for identical, unrestricted assets or liabilities; Level 2 —Quoted prices in markets that are not considered to be active or financial instrument valuations for which all significant inputs are observable, either directly or indirectly; and Level 3 —Prices or valuations that require inputs that are both significant to the fair value measurement and unobservable. To the extent that the valuation is based on models or inputs that are less observable or unobservable in the market, the determination of fair value requires more judgment. Accordingly, the degree of judgment exercised by the Company in determining fair value is greatest for instruments categorized in Level 3. Property and Equipment, net Property and equipment are recorded at cost less accumulated depreciation and amortization. Depreciation and amortization expense is recognized using the straight-line method over the estimated useful lives of the related assets as follows: Estimated Useful Laboratory equipment 3 Furniture and office equipment 3 Leasehold improvements Shorter of remaining life Construction in process N/A Depreciation and amortization expense is included in research and development and general and administrative expenses. Major additions and upgrades are capitalized; maintenance and repairs, which do not improve or extend the life of the respective assets, are expensed as incurred. Upon retirement or sale, the cost of assets disposed of, and the related accumulated depreciation and amortization are removed from the respective accounts and any resulting gain or loss is included in income (loss) from operations. Impairment of Long-Lived Assets The Company evaluates its long-lived assets, which consist of property and equipment and operating lease right-of-use assets, whenever events or changes in circumstances indicate that the carrying value of an asset may not be recoverable. Factors that the Company considers in deciding when to perform an impairment review include significant underperformance of the business in relation to expectations, significant negative industry or economic trends, and significant changes or planned changes in the use of the assets. Management then determines whether the remaining useful life continues to be appropriate, or whether there has been an impairment of long-lived assets based primarily upon whether expected future undiscounted cash flows are sufficient to support the assets’ recovery. Recoverability of these assets is measured by comparison of the carrying amount of the asset to the future undiscounted cash flows the asset is expected to generate. If the asset is considered to be impaired, the amount of any impairment is measured as the difference between the carrying value and the fair value of the impaired asset. The Company recognized no impairment losses for the years ended December 31, 2023 and 2022. Business Combinations The Company determines whether a transaction or other event is a business combination by determining whether the assets acquired and liabilities assumed constitutes a business. Business combinations are accounted for by applying the acquisition method as set out by ASC 805, Business Combinations (“ASC 805”). The acquisition method of accounting requires the acquirer to recognize and measure all identifiable assets acquired, liabilities assumed and any noncontrolling interest in the acquiree at their acquisition-date fair values, with certain exceptions for specific items. Goodwill is measured as the excess of the consideration transferred in the business combination over the net acquisition date amounts of the identifiable assets acquired and the liabilities assumed. Alternatively, if the acquisition date amounts of the identifiable assets acquired and the liabilities assumed exceeds the consideration transferred, a gain on bargain purchase is recognized in the consolidated statements of operations and comprehensive loss. The consideration transferred in a business combination is measured as the sum of the fair values of the assets transferred, the liabilities incurred to former owners of the target and the equity interests issued. The results of operations of businesses acquired by the Company are included in the Company’s consolidated statements of operations and comprehensive loss from the respective acquisition date. Where the acquirer exchanges its share-based payment awards for awards held by grantees of the acquiree, such exchanges are treated as a modification of share-based payment awards and are referred to as replacement awards. The replacement awards are measured as of the acquisition date and the portion of the fair-value-based measure of the replacement award that is attributable to pre-combination service is considered part of the consideration transferred. For awards with service-based vesting conditions only, the amount attributable to pre-combination service is the fair-value-based measure of the acquiree award multiplied by the ratio of the employee’s pre-combination service period to the greater of the total service period or the original service period of the acquiree award. Acquisition-related costs, including advisory, legal and other professional fees and administrative fees are expensed as incurred except for the costs of issuing equity securities, which are recognized as a reduction to the amounts recognized in the consolidated statements of stockholders' equity for the respective equity issuance. Intangible Assets, Net Acquired In-Process Research & Development The Company’s indefinite-lived intangible assets consist of in-process research and development (“IPR&D”), which were acquired in connection with the acquisition of Apexigen. IPR&D represents the fair value assigned to research and development projects acquired which are in-process, but not yet completed at the time of acquisition. The primary basis for determining the completion of these projects is obtaining regulatory approval to market the underlying products in an applicable geographic region. The Company classifies IPR&D acquired in a business combination as an indefinite-lived intangible asset until the associated research and development efforts are either completed or abandoned. IPR&D becomes definite-lived upon the completion or abandonment of the associated research and development efforts. Indefinite-lived intangible assets are not amortized, but evaluated for impairment on an annual basis or more frequently if an indicator of impairment is identified. All research and development costs incurred subsequent to the acquisition of IPR&D are expensed as incurred. Definite-Lived Intangible Assets Definite-lived intangible assets are recorded at cost, net of accumulated amortization, and, if applicable, impairment charges. Definite-lived intangible assets consist of retained royalty rights under certain Apexigen agreements. The useful lives of these royalty rights are 3- and 13-years, which were determined based on the terms and conditions underlying the licensing agreements and the expected uses of the assets by the Company. Amortization of defined-lived intangible assets is recorded over the assets’ estimated useful lives on a straight-line basis and is included as part of “Research and development” within the accompanying consolidated statements of operations and comprehensive loss. Impairment of Intangible Assets The Company evaluates its intangible assets, including both acquired IPR&D and definite-lived intangible assets, for impairment at least annually and whenever events or changes in circumstances indicate that the carrying value of an asset may not be recoverable. Factors that the Company considers in deciding when to perform an impairment review include significant underperformance of the business in relation to expectations, significant negative industry or economic trends, and significant changes or planned changes in the use of the assets. If the projected undiscounted cash flows of the intangible asset are less than the carrying amount, the intangible asset is written down to its fair value in the period in which the impairment occurs. The Company recognized no impairment losses for the year ended December 31, 2023. The Company had no intangible assets during the year ended December 31, 2022. Leases Operating lease right-of-use (“ROU”) assets represent the Company’s right to use an underlying asset during the lease term, and operating lease liabilities represent the Company’s obligation to make lease payments arising from the lease. Operating lease ROU assets and lease liabilities are initially recognized and measured based on the present value of the future fixed lease payments over the expected lease term at the commencement date calculated using the Company’s incremental borrowing rate applicable to the lease asset, unless the implicit rate is readily determinable. The Company determines the lease term as the non-cancelable period of the lease and may include options to extend or terminate the lease when it is reasonably certain that the Company will exercise that option. Operating lease ROU assets also include any initial direct costs incurred and any lease payments made on or before the lease commencement date, less lease incentives received. Operating lease ROU assets are subsequently measured throughout the lease term at the carrying amount of the lease liability, plus initial direct costs, plus (minus) any prepaid (accrued) lease payments, less the unamortized balance of lease incentives received. Leases with a term of 12 months or less are not recognized on the consolidated balance sheets. Lease expense for minimum lease payments is recognized on a straight-line basis over the lease term. Variable lease costs such as common area costs and other operating costs are expensed as incurred. The Company accounts for lease and non-lease components as a single lease component for all its facilities leases. Investment in Joint Venture Investment in the Company’s joint venture is accounted for using the equity method of accounting. The Company applies the equity method of accounting to investments when the Company has significant influence, but not controlling interest in the investee. Judgment regarding the level of influence over equity method investment includes considering key factors such as ownership interest, representation on the board of directors, participation in policy-making decisions and material intercompany transactions. Under the equity method, investments are initially recorded at cost and are adjusted for dividends, distributed and undistributed earnings and losses, and additional investments. In the event the Company’s share of a joint venture’s cumulative losses exceeds the Company’s investment balance, the balance is reported at zero value until proportionate income exceeds the losses. The Company assesses investments for impairment whenever events or changes in circumstances indicate that the carrying value of an investment may not be recoverable. Warrants The Company accounts for warrants to purchase shares of its common stock in accordance with the guidance in ASC 480, Distinguishing Liabilities from Equity (“ASC 480”) and ASC 815, Derivatives and Hedging (“ASC 815”). The Company classifies warrants issued for the purchase of shares of its common stock as either equity or liability instruments based on an assessment of the specific terms and conditions of each respective contract. The assessment considers whether the warrants are freestanding financial instruments or embedded in a host instrument, whether the warrants meet the definition of a liability pursuant to ASC 480, whether the warrants meet the definition of a derivative under ASC 815, and whether the warrants meet all of the requirements for equity classification under ASC 815. This assessment, which requires the use of professional judgment, is conducted at the time of warrant issuance and as of each subsequent quarterly period end date while the warrants are outstanding. For issued or modified warrants that meet all of the criteria for equity classification, the warrants are required to be recorded as a component of equity at the time of issuance. For issued or modified warrants that do not meet all the criteria for equity classification, the warrants are required to be recorded as liabilities at their initial fair value on the date of issuance, and each balance sheet date thereafter. Changes in the estimated fair value of the warrants classified as liabilities are recognized as a non-cash gain or loss in the consolidated statements of operations and comprehensive loss. Contingencies The Company, from time to time, may be a party to various disputes and claims arising from normal business activities. The Company continually assesses disputes and claims including resulting litigation to determine if an unfavorable outcome would lead to a probable loss or reasonably possible loss which could be estimated. The Company accrues for all contingencies at the earliest date at which the Company deems it probable that a liability has been incurred and the amount of such liability can be reasonably estimated. If the estimate of a probable loss is a range and no amount within the range is more likely than another, the Company accrues the minimum of the range. In the cases where the Company believes that a reasonably possible loss exists, the Company discloses the facts and circumstances of the contingencies, including an estimable range, if possible. Revenue Recognition The Company recognizes revenue based on guidance under ASC 606, Revenue from Contracts with Customers (“ASC 606”). Under ASC 606, revenue is recognized when the customer obtains control of the promised goods or services, at an amount that reflects the consideration the Company expects to receive in exchange for those goods or services. The Company has not commenced sales of its drug candidates and does not have any products approved for marketing as of December 31, 2023. The Company may also earn contingent fees, including milestone payments, based on counterparty performance and royalties on sales, from collaborations and other out-license arrangements. The Company recognizes milestone payments as revenue once the underlying events are probable of being met and there is not a significant risk of reversal. The Company recognizes sales-based royalties as revenue when the underlying sales occur and there are no constrains to recognize the revenue for such sales-based royalties . Research and Development Expenses The Company expenses research and development costs as incurred. The Company’s research and development expenses consist primarily of license fees to acquire intellectual property which does not meet the definition of intangible assets and costs incurred in performing research and development activities, including personnel-related expenses such as salaries, stock-based compensation and benefits, facilities costs, depreciation as well as external costs from third parties who conduct research and development activities (including manufacturing) on behalf of the Company. The Company accrues expenses related to development activities performed by third parties based on an evaluation of services received and efforts expended pursuant to the terms of the contractual arrangements. Payments under some of these contracts depend on preclinical and/or clinical trial milestones. There may be instances in which payments made to the Company’s vendors will exceed the level of services provided and result in a prepayment of expenses. In accruing service fees, the Company estimates the time period over which services will be performed and the level of effort to be expended in each period. If the actual timing of the performance of services or the level of effort varies from the estimate, the Company adjusts the accrual or prepaid expense accordingly. Stock-Based Compensation The Company maintains an equity incentive plan as a long-term incentive for employees, consultants and directors. The Company accounts for all stock-based awards granted to employees and non-employees based on their fair value on the date of the grant and recognizes compensation expense for those awards over the requisite service period, which is generally the vesting period of the respective award. The grant date fair value of the stock-based awards with graded vesting is recognized on a straight-line basis over the requisite service period. The Company recognizes forfeitures related to stock-based compensation awards as they occur and reverses any previously recognized compensation cost associated with forfeited awards in the period the forfeiture occurs. The Company classifies stock-based compensation expense in the consolidated statements of operations and comprehensive loss in the same manner in which the award recipients’ payroll costs are classified or in which the award recipients’ service payments are classified. The Company values its stock options with service conditions using the Black-Scholes option-pricing model. The Company uses certain assumptions to determine fair value of the stock options pursuant to the Black-Scholes option-pricing model, including the expected life of the award, volatility of the underlying shares, the risk-free interest rate, expected dividend yield and the fair value of the Company’s common stock. Since the Company lacks sufficient historical option exercise data to provide a reasonable basis upon which to estimate the expected term, the Company uses the simplified method described in the U.S. Securities and Exchange Commission's ("SEC") Staff Accounting Bulletin No. 107, Share-Based Payment (“SAB 107”), to determine the expected life of the option grants. The Company lacks sufficient company-specific historical and implied volatility information. Therefore, the Company estimates the expected stock volatility based on the historical volatility of a publicly traded set of peer companies. The risk-free interest rate is based on the rates paid on securities issued by the U.S. Treasury with a term approximating the expected life of the equity award. As the Company has never paid and does not anticipate paying cash dividends on its common stock, the expected dividend yield is considered as zero. Income Taxes The Company accounts for income taxes in accordance with FASB ASC 740, Income Taxes (“ASC 740”), which requires the use of the asset and liability method of accounting for income taxes. Under this method, deferred tax assets and liabilities are determined on the basis of the differences between amounts in the consolidated financial statements and the tax bases 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 in income tax (benefit) expense in the consolidated statements of operations and comprehensive loss in the period that includes the enactment date. The Company recognizes deferred tax assets to the extent that it believes these assets are more likely than not to be realized. In making such a determination, the Company considers all available positive and negative evidence, including future reversals of existing taxable temporary differences, projected future taxable income, tax-planning strategies and results of recent operations. If the Company determines that it would be able to realize its deferred tax assets in the future in excess of its net recorded amount, the Company would make an adjustment to the deferred tax asset valuation allowance, which would reduce the provision for income taxes. Changes in recognition or measurement are reflected in the period in which the change in judgment occurs. When uncertain tax positions exist, the Company recognizes the tax benefit of tax positions to the extent that the benefit will more likely than not be realized. The determination as to whether the tax benefit will more likely than not be realized is based upon the technical merits of the tax position as well as consideration of the available facts and circumstances. Net Loss per Share Basic net income (loss) per share attributable to common stockholders is computed by dividing net income (loss) attributable to common stockholders by the weighted average number of common shares outstanding for the period. Diluted net income (loss) per share attributable to common stockholders is computed by dividing the diluted net income (loss) attributable to common stockholders by the diluted weighted average number of common shares outstanding for the period, including potential dilutive common shares. In periods in which the Company reports a net loss, all common stock equivalents are deemed anti-dilutive such that basic net loss per common share and diluted net loss per common share are equivalent. Potentially dilutive common stock has been excluded from the diluted net loss per common share computations in all periods presented because such securities have an anti-dilutive effect on net loss per common share due to the Company’s net loss. There are no reconciling items used to calculate the weighted-average number of total common stock outstanding for basic and diluted net loss per common share data. Recently Adopted Accounting Pronouncements In June 2016, the FASB issued ASU 2016-13, Financial Instruments-Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments (“ASU 2016-13”), which requires the measurement and recognition of expected credit losses for financial assets held at amortized cost. ASU 2016-13 replaces the existing incurred loss impairment model with an expected loss model that requires the use of forward-looking information to calculate credit loss estimates. It also eliminates the concept of other-than-temporary impairment and requires credit losses on available-for-sale debt securities to be recorded through an allowance for credit losses instead of as a reduction in the amortized cost basis of the securities. For "emerging growth companies", ASU 2016-13 is effective for fiscal years beginning after December 15, 2022, and interim periods within those fiscal years. On January 1, 2023 , the Company adopted ASU 2021-08, which did no t have a material effect on the Company's financial position, results of operations, or cash flows. In October 2021, the FASB issued ASU 2021-08, Business Combinations (Topic 805): Accounting for Contract Assets and Contract Liabilities from Contracts with Customers (“ASU 2021-08”), which amends the accounting related to contract assets and liabilities acquired in business combinations. ASU 2021-08 requires that entities recognize and measure contract assets and contract liabilities acquired in a business combination in accordance with ASC Topic 606, Revenue from Contracts with Customers . ASU 2021-08 is effective for fiscal years beginning after December 15, 2022, including interim periods within those fiscal years, and should be applied prospectively to businesses combinations occurring on or after the effective date of the amendment. Early adoption is permitted, including adoption in an interim period. On January 1, 2023 , the Company adopted ASU 2021-08, which did no t have a material effect on the Company's financial position, results of operations, or cash flows. Recently Issued Accounting Pronouncements In August 2020, the FASB issued ASU 2020-06, Debt – Debt with Conversion and Other Options (Subtopic 470-20) and Derivatives and Hedging – Contracts in Entity’s Own Equity (Subtopic 815-40) (“ASU 2020-06”). ASU 2020-06 revises the guidance on calculating earnings per share, requiring use of the if-converted method for all convertible instruments and rescinding an entity’

Acquisition of Apexigen

Acquisition of Apexigen	12 Months Ended
	Dec. 31, 2023
Business Combinations [Abstract]
Acquisition of Apexigen	3. Acquisition of Apexigen On May 23, 2023, the Company entered into an Agreement and Plan of Merger (the “Merger Agreement”), by and among the Company, Ascent Merger Sub Corp., a Delaware corporation and wholly-owned subsidiary of the Company (“Merger Sub”), and Apexigen, a Delaware corporation and a clinical-stage biopharmaceutical company focused on discovering and developing innovative antibody therapeutics for oncology. On August 23, 2023 (the “Closing Date”), the Company completed the acquisition of Apexigen contemplated by the Merger Agreement, pursuant to which, Merger Sub merged with and into Apexigen, with Apexigen surviving as a wholly owned subsidiary of the Company (the “Merger”). The Company issued 4,344,435 shares of its common stock to Apexigen stockholders. The Merger expanded the Company's pipeline with the addition of sotigalimab (now PYX-107), a CD40 agonist with demonstrated anti-cancer activity in patients who previously progressed on PD-(L)1 inhibitors, and enhanced the Company’s ADC capabilities with an addition of the commercially and clinically validated APXiMAB platform to generate novel antibodies that can be optimized for targeted payload delivery. Under the Merger Agreement, each share of Apexigen common stock outstanding as of the Closing Date was automatically converted into the right to receive 0.1725 shares of the Company’s common stock (“Exchange Ratio”). Additionally, each outstanding stock option, restricted stock unit (“RSU”) and warrant issued by Apexigen was assumed and converted into stock options, RSUs and warrants to acquire the Company’s common stock, on substantially similar terms and conditions as were applicable under such Apexigen equity plans (collectively, the “Replacement Awards”) and warrant agreements. The number of stock options, RSUs and warrants and their respective exercise prices were adjusted by the Exchange Ratio. The Company accounted for the Merger as a business combination using the acquisition method in accordance with ASC 805. Under the acquisition method of accounting, the Company was identified as the acquirer, with Apexigen as the acquiree, and August 23, 2023 was determined as the acquisition date. Accordingly, the assets acquired and liabilities assumed are recorded at their estimated fair value on the date of acquisition. Apexigen’s results of operations have been included in the consolidated statements of operations and comprehensive loss since the date of acquisition and were not material to the Company’s results of operations for the year ended December 31, 2023. The consideration transferred for Apexigen includes the shares issued by the Company to former Apexigen stockholders, the fair value of replacement awards (both stock options and RSUs) of the Company granted to Apexigen grantholders attributable to pre-combination service and the fair value of Apexigen warrants converted to the Company’s warrants. The following table summarizes the acquisition date fair value of the consideration transferred for Apexigen (in thousands, except share and per-share information): Fair value of Pyxis Oncology common stock issued to Apexigen stockholders (i) $ 9,970 Fair value of replacement options and RSUs attributable to pre-combination service (ii) 144 Fair value of replacement warrants (iii) 618 Provisional purchase price $ 10,732 (i) The fair value of the Company’s common stock issued as consideration transferred was based on the closing price of Pyxis Oncology common stock as reported on The Nasdaq Global Select Market on the day prior to the Closing Date. (ii) At the Closing Date, the Company replaced 4,128,809 Apexigen stock options and 200,000 Apexigen RSUs with approximately 712,181 Pyxis Oncology stock options (“Replacement Options”) and 34,500 Pyxis Oncology RSUs (“Replacement RSU Awards”). The acquisition date fair value of the Replacement Options was determined by the Black-Scholes option-pricing model and the acquisition date fair value attributable to the pre-combination services of $ 0.1 million is included in the purchase price. (iii) At the Closing Date, the Company replaced approximately 5,815,613 Apexigen warrants with approximately 1,003,191 Pyxis Oncology warrants (“Replacement Warrants”). The acquisition date fair value of the Replacement Warrants is $ 0.6 million, which was determined using the Black-Scholes option-pricing model and is included in the purchase price. The following table summarizes the preliminary acquisition date fair value of the assets acquired and liabilities assumed (in thousands): Amount Assets acquired: Cash and cash equivalents $ 6,660 Prepaid expenses and other current assets 519 Intangible assets, net 24,458 Total identifiable assets $ 31,637 Liabilities assumed: Accounts payable ( 4,548 ) Accrued liabilities ( 7,531 ) Deferred tax liability, net ( 2,164 ) Deferred revenue ( 6,662 ) Total identifiable liabilities ( 20,905 ) Net assets acquired $ 10,732 The assets acquired and liabilities assumed were measured based on management’s estimates of the fair value as of the acquisition date. Intangible assets, net includes both IPR&D and definite-lived intangible assets acquired as part of the Merger. IPR&D represents Apexigen's research and development assets, which were in-process, but not yet completed, and which the Company has the opportunity to advance. The definite-lived intangible assets represent royalty rights under certain Apexigen out-licensing agreements that were assumed by the Company upon the Merger Agreement. The fair value of the intangible assets, including both royalty rights and IPR&D acquired, was determined using the income approach. Under this method, an intangible asset's fair value is equal to the present value of the incremental after-tax cash flows attributable to the intangible asset. The fair value measurements were primarily based on significant inputs not observable in the market and thus represent a Level 3 measurement. The estimates the Company uses are consistent with the plans and estimates that it uses to manage its business. Significant assumptions utilized in the Company’s income approach model include the discount rate, timing of clinical studies and regulatory approvals, the probability of success of its research and development programs, timing of commercialization of these programs, forecasted sales, selling, general and administrative expenses, capital expenditures, as well as anticipated growth rates. Deferred tax liabilities, net of $ 2.2 million relates to the IPR&D acquired as part of the Merger. The fair value estimates for the intangible assets are considered provisional and subject to adjustment during the measurement period, not to exceed one year after the date of acquisition, as additional information becomes available and as additional analyses are performed. The Company incurred transaction related costs of $ 1.7 million for the year ended December 31, 2023. All transaction related costs were recognized in general and administrative expenses on the consolidated statements of operations and comprehensive loss. No issuance costs were incurred relating to the issuance of shares to Apexigen stockholders. Supplemental Pro Forma Information (Unaudited) On a pro forma basis to give effect to the Merger as if it occurred on January 1, 2022, net loss for the years ended December 31, 2023 and 2022, respectively, would have been as follows: Year Ended December 31, 2023 2022 Net loss $ ( 97,791 ) $ ( 153,207 ) The supplemental pro forma net loss includes a pro forma adjustment related to amortization expense for the acquired royalty rights as if the Merger occurred on January 1, 2022.

Licensing Agreements

Licensing Agreements	12 Months Ended
	Dec. 31, 2023
License Agreements [Abstract]
Licensing Agreements	4. Licensing Agreements The University of Chicago Agreement In April 2020, the Company entered into a license agreement (the “University License Agreement”), as well as a sponsored research agreement, with the University of Chicago (the “University”). Under the terms of the license, the Company has the global right to develop and commercialize products that are covered by a valid claim of a licensed patent, incorporate or use the licensed know-how and materials or are known to assess, modulate or utilize the activity of certain specified biological targets. In partial consideration for the license from the University, the Company issued to the University 48,919 shares of its common stock in 2020. Pursua nt to the University License Agreement, the Company is obligated to pay potential development and commercial milestones of up to $ 7.7 million as well as running royalties on net sales of licensed products at varying rates ranging from less than a percent to the low single digits, subject to a minimum annual royalty of up to $ 3.0 million during certain years following the effective date. The Company is also obligated to pay the University a percentage of certain sublicensing revenue ranging from low- to mid-teens based on the date of entering into the applicable sublicense. The Company assessed the milestone and royalty events under the University License Agreement as of December 31, 2023 and 2022, and determined that no such amounts were required. Pfizer Inc. Agreements In December 2020, the Company entered into a license agreement (as amended, the “Pfizer License Agreement”) with Pfizer Inc. (“Pfizer”) for worldwide development and commercialization rights to ADC product candidates directed to certain licensed targets, including PYX-201 and PYX-203, and products containing the ADC product candidates. The Company’s rights are exclusive with respect to certain patents owned or controlled by Pfizer covering the licensed ADCs. The initial licensed targets include CD123 and extra domain B (EDB+FN) and the Company has the option to expand the scope of its license to add additional licensed targets that have not been licensed to a third party or are not the subject of a Pfizer ADC development program. The Pfizer License Agreement became effective for the Company in March 2021. Pursuant to the Pfizer License Agreement, the Company paid a combined $ 25.0 million for the license fee, consisting of an upfront cash payment of $ 5.0 million and issued 12,152,145 shares of Series B convertible preferred stock, which was converted into 1,911,015 shares of its common stock upon the initial public offering (“IPO”) in October 2021, with a value of $ 20.0 million to Pfizer. On October 6, 2022, the Company entered into an amended and restated license agreement (the “A&R License Agreement”) with Pfizer, which amends and restates the Pfizer License Agreement. Pursuant to the A&R License Agreement, Pfizer granted to the Company exclusive worldwide rights under Pfizer’s Flexible Antibody Conjugation Technology ( “FACT”) Platform to develop and commercialize ADC product candidates directed to certain licensed targets, including PYX-201 and PYX-203, and products containing the ADC product candidates. Additional ADC targets may be licensed for a nominal upfront payment and milestones. In accordance with the terms of the A&R License Agreement, the Company issued 2,229,654 shares of its common stock to Pfizer in October 2022, paid $ 8.0 million to Pfizer in January 2023 and issued 1,811,594 shares of its common stock to Pfizer in March 2023. The Company is also obligated to pay future contingent payments including development, regulatory and commercial milestones up to an aggregate of $ 665 million for the first four licensed ADCs. In addition, the Company is required to pay future contingent payments including development, regulatory and commercial milestones for ADCs to each additional licensed target beyond the first four licensed ADC targets developed and commercialized via the FACT Platform. Additionally, if ADC licensed products are launched, the Company will pay Pfizer tiered royalties on net sales of licensed products in varying royalty rates ranging from low single digits to mid-teens. The Company’s royalty obligations apply on a licensed product-by-licensed product and country-by-country basis from first commercial sale until the latest to occur of: (1) 12 years from first commercial sale; (2) the expiration of all regulatory or data exclusivity; and (3) the expiration of the last valid claim of a licensed patent covering the licensed product in a country. The Company is also obligated to pay Pfizer a percentage of certain sublicensing revenue ranging from twenty percent to low-double digits based on the stage of development of the licensed product at the time of entering into the applicable sublicense. The Company assessed the milestone and royalty events under A&R License Agreement as of December 31, 2023 and 2022, and determined that no such amounts were required. License Agreement with Biosion USA, Inc. On March 28, 2022, the Company entered into a license agreement (the “Biosion License Agreement”) with Biosion USA, Inc. (“Biosion”), pursuant to which the Company obtained an exclusive, worldwide (other than Greater China (mainland China, Hong Kong, Macau and Taiwan)) license for development, manufacture and commercialization rights for BSI-060T, a Siglec-15 targeting antibody, an IO product candidate (now referred to as PYX-106), and products containing the licensed compound. Under the terms of the Biosion License Agreement, each party granted to the other party a right of first offer to obtain an exclusive license in the other party’s territory (Greater China for Biosion, and the rest of the world for Pyxis) to develop, manufacture and commercialize any bi-specific or multi-specific antibody any antibody-drug conjugate controlled by a party or its affiliate that inhibits, modulates or binds to Siglec-15 as an intended mechanism of action. Pursuant to the Biosion License Agreement, the Company paid an upfront license fee of $ 10.0 million, which was recorded as research and development expenses. The Company is also obligated to pay future contingent payments including development, regulatory and commercial milestones up to an aggregate of $ 217.5 million in case of normal approval and $ 222.5 million in case of accelerated approval. Additionally, if products are launched, the Company will pay Biosion tiered royalties on net sales of licensed products in varying royalty rates ranging from low single digits to low teens. The Company’s royalty obligations apply on a licensed product-by-licensed product and country-by-country basis from first commercial sale until the latest to occur of: (1) 12 years from first commercial sale; (2) the expiration of all regulatory or data exclusivity; and (3) the expiration of the last valid claim of a licensed patent covering the licensed product in a country. The Company is also obligated to pay Biosion a percentage of certain sublicensing revenue ranging from mid-double to low-double digits based on the stage of development of the licensed product at the time of entering into the applicable sublicense. The Company assessed the milestone and royalty events involving Biosion as of December 31, 2023 and 2022, and determined that no such amounts were required. LegoChem Biosciences, Inc. Agreements In December 2020, the Company entered into a license agreement (the “LegoChem License Agreement”) and an opt-in, investment and additional consideration agreement (the “Opt-In Agreement”) with LegoChem Biosciences, Inc. (“LegoChem”). Pursuant to the LegoChem License Agreement, the Company obtained worldwide (other than Korea) license for development and commercialization rights for LCB67, an ADC product candidate targeting DLK-1, and products containing the licensed compound. The Company paid $ 9.0 million in March 2021 to LegoChem, which was recorded as research and development expenses. Additionally, the Company may purchase certain initial quantities of licensed products from LegoChem for an estimated cost of $ 7.0 million. The Company is obligated to make future contingent payments including development, regulatory and commercial milestones as well as running royalties on net sales of licensed products at varying rates. In addition, as part of the Opt-in Agreement, LegoChem exercised an option to pay $ 8.0 million to the Company, in exchange for the right to receive a milestone payment (the “Extra Milestone Payment”) of $ 9.6 million upon the earliest to occur of certain events, including the date of pricing or offer of the first public offering of its common stock or if the Company is the subject of a change in control transaction. Upon the Company's IPO in October 2021, the extra milestone payment event triggered, and the Company paid $ 9.6 million in January 2022 to LegoChem. In 2022, the Company stopped the continued development of LCB67, based on review and analysis of data from the toxicity studies, and anticipated clinical use and commercial prospects of anti-DLK1 ADC. Due to stoppage of clinical development of LCB67, no amounts are due and payable related to the manufacturing of the initial quantities of licensed product and no milestone or royalty events are expected. Acquired Out-Licensing Agreements In August 2023, the Company completed the acquisition of Apexigen, as detailed in Note 3, Acquisition of Apexigen , and assumed all out-licensing agreements of Apexigen upon the Merger Agreement. Described below are the out-license relationships and the related agreements under which the Company may receive milestone or royalty payments. The aggregate payments received from these relationships post-acquisition of Apexigen was $ 1.0 million and the Company has $ 7.7 million in deferred revenue relating to certain royalty payments as of December 31, 2023, as detailed below. Beovu and Novartis Antibody Candidate Discovery and Development Agreement In March 2007, Epitomics (Apexigen's predecessor), entered into an antibody candidate discovery and development agreement with ESBATech AG, or ESBA Tech, in March 2007 (the “ESBATech Agreement”). ESBATech was acquired by Alcon Research, Ltd. ("ARL") in 2009 and later merged with Novartis AG (“Novartis”) in 2011. Novartis, the successor in interest to ESBATech, has successfully developed and commercialized one of those drug product candidates, brolucizumab-dbll, a single-chain antibody fragment (scFv) targeting all of the isoforms of VEGF-A, which was approved for commercial sale in 2019 and marketed under the brand name Beovu®. Novartis and its predecessors have paid all upfront fees and milestone payments due under the ESBATech Agreement. Novartis is obligated to pay Apexigen a very low single-digit royalty on net sales of the Beovu® product. However, Novartis has disputed its obligation to pay these royalties on Beovu® sales under this agreement. As a result, the Company determined that any sales-based Beovu® product royalties received under this agreement through December 31, 2023 should be fully constrained. The Company assesses this position at each period end to determine if events or changes in circumstances indicate a change in position. As of December 31, 2023, deferred revenue totaled $ 7.7 million. Simcere License and Collaboration Agreement In December 2008, Epitomics (Apexigen's predecessor) and Jiangsu Simcere Pharmaceutical R&D Co., Ltd. ("Simcere") entered into a license and collaboration agreement (the “Simcere Agreement”) for the development and commercialization of suvemcitug (BD0801) for oncology in China. Suvemcitug is, a humanized anti-VEGF rabbit monoclonal antibody molecule. Under the Simcere Agreement, Simcere has an exclusive, royalty-bearing license (without the right to sublicense) to rights in certain intellectual property to develop and commercialize suvemcitug in the field of oncology therapeutics in China. Simcere granted the Company a non-exclusive, royalty-free, worldwide license (without the right to sublicense) to improvements derived from suvemcitug using the intellectual property the Company licensed to Simcere. Simcere is obligated to pay the Company milestone payments for achievement of certain clinical development milestones and low to high single-digit percentage royalties on net sales of suvemcitug in China until 15 years after the first commercial sale of suvemcitug. The Company assessed the milestone and royalty events involving Simcere as of December 31, 2023 and determined that no such amounts were receivable. T-Mab/Mabwell Agreement In May 2008, Epitomics (Apexigen's predecessor) and Jiangsu T-Mab Biotechnology Ltd., Co. (“T-Mab”) entered into a license, co-development and contract manufacture agreement (the “T-Mab Agreement”) for the development and commercialization of therapeutic candidates, each directed to a specified target for specified fields, including VEGF for the treatment of ocular diseases, in China. Mabwell (Shanghai) Bioscience Co., Ltd. (“Mabwell”) acquired T-Mab in 2015. Under the agreement, Mabwell was granted an exclusive, royalty-bearing, perpetual license (without the right to sublicense) to rights in certain intellectual property to develop and commercialize such therapeutic candidates. Mabwell is obligated to pay the Company a mid-single-digit percentage royalty on net sales of such therapeutic candidates in China. The royalty term for 9MW0211, an anti-VEGF antibody licensed under the T-Mab Agreement, will begin on the first commercial sale in China. The Company assessed the milestone and royalty events involving Mabwell as of December 31, 2023 and determined that no such amounts were receivable. Toray Sublicense Agreement In May 2012, Epitomics (Apexigen's predecessor) and Toray Industries, Inc. (“Toray”), entered into a non-exclusive sublicense agreement (the “Toray Agreement”) under which Epitomics granted Toray a non-exclusive, worldwide sublicense, with the right to grant further sublicenses, to develop and commercialize drug product candidates that Toray developed using antibodies created using the APXiMAB platform that target certain molecules to use in the development of its drug product candidates. Under the Toray Agreement, Toray paid an upfront fee, and agreed to pay certain development- and regulatory-related milestone payments and a low single-digit percentage royalty on net sales of licensed products by Toray or its affiliates. Toray is also obligated to pay the Company a mid-teens percentage of certain payments Toray receives from sublicensees under the Toray Agreement, which payments may limit Toray’s obligations to pay the milestone payments described above. The Toray Agreement continues on a product-by-product and country-by-country basis until 10 years after the first commercial sale of such product in such country. The Company assessed the milestone and royalty events involving Toray as of December 31, 2023 and determined that no such amounts were receivable.

Joint Venture

Joint Venture	12 Months Ended
	Dec. 31, 2023
Equity Method Investments and Joint Ventures [Abstract]
Joint Venture	5. Joint Venture In March 2021, the Company entered into definitive transaction agreements with Alloy Therapeutics, Inc. (“Alloy”) and Voxall Therapeutics, LLC (“Voxall”), to finance and operate Voxall, a joint venture company formed in collaboration with Alloy to leverage the Company’s technology and Alloy’s ATX-Gx ™ platform and antibody discovery services. Voxall granted to the Company and Alloy, 50 % of the voting membership units of Voxall in exchange for certain contributions, including $ 50 thousand from both the Company and Alloy. The Company accounted for the investment in Voxall under the equity method of accounting and recognizes its share of losses of Voxall only to the extent of the carrying value of its investment in Voxall. See Note 20, Subsequent Events , for further discussion of developments regarding Voxall subsequent to the balance sheet date and prior to the filing of this Annual Report on Form 10-K for the year ended December 31, 2023.

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2023
Fair Value Disclosures [Abstract]
Fair Value Measurements	6. Fair Value Measurements The following tables present the financial instruments carried at fair value on a recurring basis as of December 31, 2023 and 2022, respectively, in accordance with the FASB ASC 820 hierarchy (in thousands): December 31, 2023 Level 1 Level 2 Level 3 Total Cash equivalents Money market funds $ 8,360 $ — $ — $ 8,360 Marketable debt securities U.S. Treasury securities 109,634 — — 109,634 Total $ 117,994 $ — $ — $ 117,994 December 31, 2022 Level 1 Level 2 Level 3 Total Cash Equivalents Money market funds $ 177,279 $ — $ — $ 177,279 Restricted Cash Money market funds 1,472 — — 1,472 Total $ 178,751 $ — $ — $ 178,751 The Company’s cash equivalents represent deposits in a short-term money market fund quoted in an active market and classified as Level 1 assets. Marketable debt securities include investments in United States Treasury securities and are classified as Level 1 assets as they are valued using quoted prices in active markets. There were no assets or liabilities measured at fair value on a nonrecurring basis at December 31, 2023 and 2022. There were no transfers between Level 1 and Level 2 of the fair value hierarchy during the years ended December 31, 2023 and 2022.

Marketable Debt Securities

Marketable Debt Securities	12 Months Ended
	Dec. 31, 2023
Investments, Debt and Equity Securities [Abstract]
Marketable Debt Securities	7. Marketable Debt Securities Marketable debt securities, all of which were classified as available-for-sale, consist of the following (in thousands): December 31, 2023 Amortized Unrealized Unrealized Aggregate Marketable debt securities U.S. Treasury securities $ 109,571 $ 71 $ ( 8 ) $ 109,634 As of December 31, 2022, the Company did no t have marketable debt securities. As of December 31, 2023, the remaining contractual terms of the U.S. Treasury securities were less than 12 months. As of December 31, 2023, the Company held one security in an unrealized loss position of $ 8 thousand and had a fair value of $ 41.7 million. There were no securities in a continuous unrealized loss position for greater than twelve months at December 31, 2023. To date, we have not recognized any allowances for credit losses or impairments in relation to our marketable securities as these securities are comprised of high credit quality, investment grade securities that we do not intend or expect to be required to sell prior to their anticipated recovery, and the decline in fair value of these securities is attributable to factors other than credit losses. Interest and Investment Income Interest and investment income consisted of the following (in thousands): Year Ended December 31, 2023 2022 Interest income $ 1,842 $ 2,764 Accretion of discount, net 4,788 — Total interest and investment income $ 6,630 $ 2,764

Prepaid Expenses and Other Curr

Prepaid Expenses and Other Current Assets	12 Months Ended
	Dec. 31, 2023
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Prepaid Expenses and Other Current Assets	8. Prepaid Expenses and Other Current Assets Prepaid expenses and other current assets consisted of the following (in thousands): December 31, 2023 2022 Research and development $ 2,496 $ 3,560 Insurance 1,012 1,308 Accrued interest receivable 21 598 Other 305 381 Total prepaid expenses and other current assets $ 3,834 $ 5,847

Property and Equipment, Net

Property and Equipment, Net	12 Months Ended
	Dec. 31, 2023
Property, Plant and Equipment [Abstract]
Property and Equipment, Net	9. Property and Equipment, Net Property and equipment, net, consisted of the following (in thousands): December 31, 2023 2022 Leasehold improvements $ 10,956 $ 530 Laboratory equipment 3,395 2,247 Furniture and office equipment 1,123 1,036 Construction in process — 9,177 15,474 12,990 Less: accumulated depreciation and amortization ( 3,602 ) ( 1,825 ) Total property and equipment, net $ 11,872 $ 11,165 Depreciation and amortization expense for the years ended December 31, 2023 and 2022 was $ 1.8 million and $ 0.7 million, respectively , of which $ 1.5 million and $ 0.7 million, respectively, was included within research and development expenses and $ 0.3 million and $ 15 thousand, respectively, was included in general and administrative expenses in the accompanying statements of operations and comprehensive loss.

Intangible Assets, Net

Intangible Assets, Net	12 Months Ended
	Dec. 31, 2023
Goodwill and Intangible Assets Disclosure [Abstract]
Intangible Assets, Net	10. Intangible Assets, Net Intangible assets, net, consisted of the following (in thousands): As of December 31, 2023 Estimated Useful Life Gross Carrying Accumulated Net Carrying Royalty rights 3 - 13 years $ 3,494 $ ( 150 ) $ 3,344 IPR&D Indefinite 20,964 — 20,964 Total $ 24,458 $ ( 150 ) $ 24,308 As described in Note 4, Licensing Agreements , the Company assumed all out-licensing agreements of Apexigen upon the completion of the Merger and retains royalty rights under certain Apexigen agreements. The Company recognized a definite-lived intangible asset related to these royalty rights, which was valued using the income approach and adjusted for any potential repayment provisions. Royalty rights are amortized on a straight-line basis over its useful lives, which are 3 - and 13 -years, and was determined based on the terms and conditions underlying the licensing agreements and the expected use of the asset by the Company. Useful lives are periodically evaluated to determine whether events or circumstances have occurred which indicate the need for revision. The weighted-average amortization period of the acquired royalty rights is approximately 8.3 years. Amortization expense was $ 0.2 million for the year ended December 31, 2023 and was recorded as part of “Research and development” within the accompanying consolidated statements of operations and comprehensive loss. Amortization of intangible assets for the next five years related to the intangible assets held as of December 31, 2023 is estimated to be as follows (in thousands): Years Ending December 31, Estimated Amortization Expense 2024 $ 421 2025 421 2026 322 2027 223 2028 223 Thereafter 1,734 Total $ 3,344 IPR&D represents the research and development assets of Apexigen acquired by the Company, which were in-process, but not yet completed, and which the Company has the opportunity to advance. The primary basis for determining the completion of these projects is obtaining regulatory approval to market the underlying products in an applicable geographic region. IPR&D becomes definite-lived upon the completion or abandonment of the associated research and development efforts. The Company had no intangible assets during the year ended December 31, 2022.

Accrued Expenses and Other Curr

Accrued Expenses and Other Current Liabilities	12 Months Ended
	Dec. 31, 2023
Payables and Accruals [Abstract]
Accrued Expenses and Other Current Liabilities	11. Accrued Expenses and Other Current Liabilities Accrued expenses and other current liabilities consisted of the following (in thousands): December 31, 2023 2022 Research and development expenses $ 6,594 $ 17,414 Employee compensation and benefits 5,219 4,238 Legal and professional fees 802 1,794 Other 356 1,091 Total accrued expenses and other current liabilities $ 12,971 $ 24,537

Operating Leases

Operating Leases	12 Months Ended
	Dec. 31, 2023
Leases [Abstract]
Operating Leases	12. Operating Leases Leases classified as operating leases are included in operating lease right-of-use assets (“ROU”), operating lease liabilities, current portion and operating lease liabilities, net of current portion, in the Company's consolidated balance sheets. The Company leases its office and facilities in Boston, Massachusetts under a non-cancellable operating lease agreement that continues through December 31, 2032. Under the terms of the lease agreement, the Company is responsible for certain insurance, property taxes and maintenance expenses, which represents the Company’s proportionate share of the actual expenses incurred by the landlord. The operating lease agreement contains scheduled annual rent increases over the lease term. On February 2, 2023, the Company entered into a sublease agreement for approximately 17,729 square feet of office and laboratory space in the building located at 321 Harrison Avenue, Boston, Massachusetts. The sublease included a rent-free period, with rent payments commencing on May 24, 2023. Under the terms of the sublease, the sublessee is to pay the Company approximately $ 1.5 million in year one and $ 1.9 million per year thereafter, which is subject to a 3.0 % annual rent increase, plus certain other costs under the sublease, such as operating expenses, taxes, insurance, property management fee and utilities. The Company remains jointly and severally liable under the head lease and accounts for the sublease as an operating lease. The sub-lease term commenced on March 24, 2023 and is expected to end in March 2026. The sublessee has the option to extend the sublease for a one-year period on the same terms and conditions as the current sublease, subject to a change in base rent for the extended period equal to a 3 % increase to the then current rent. Upon execution of the sublease agreement, the sublessee provided the Company a security deposit of $ 0.4 million which is held in the form of a letter of credit. The Company recognized sublease income of $ 1.8 million for the year ended December 31, 2023. The Company was not party to any finance leases during the years ended December 31, 2023 and 2022. The components of lease expense were as follows (in thousands): Year Ended December 31, 2023 2022 Lease cost Operating lease cost $ 2,666 $ 1,978 Variable lease cost 753 121 Short-term lease cost 499 1,681 Total lease cost $ 3,918 $ 3,780 Other information Operating lease right-of-use asset obtained in exchange for new operating lease liabilities $ — $ 14,497 Cash paid for amounts included in the measurement of lease liabilities, included in operating cash flows $ 2,516 $ 663 Weighted-average remaining lease term (in years) 9.00 10.00 Weighted-average discount rate 9.40 % 9.40 % Variable lease costs primarily relate to common area costs and other operating costs, which are assessed based on the Company’s proportionate share of such costs for the leased premises. Total lease costs are included as operating expenses in the Company’s consolidated statements of operations and comprehensive loss. Maturities of lease liabilities as of December 31, 2023, were as follows (in thousands): Years Ending December 31, Operating Lease Payments Sublease Receipts Net Operating Lease Payments 2024 $ 3,185 $ 1,844 $ 1,341 2025 3,278 1,898 1,380 2026 3,375 437 2,938 2027 3,473 — 3,473 2028 3,575 — 3,575 Thereafter 15,383 — 15,383 Total undiscounted payments $ 32,269 $ 4,179 $ 28,090 Less: present value adjustment ( 10,938 ) Present value of future payments 21,331 Less: current portion of operating lease liabilities ( 1,232 ) Operating lease liabilities, net of current portion $ 20,099

Common Stock Warrants

Common Stock Warrants	12 Months Ended
	Dec. 31, 2023
Share-Based Payment Arrangement [Abstract]
Common Stock Warrant	13. Common Stock Warrants As described in Note 3, Acquisition of Apexigen , pursuant to the Merger Agreement , each outstanding warrant issued by Apexigen as of the Closing Date was assumed and converted into a warrant to acquire the Company’s common stock, on substantially similar terms and conditions as were applicable under such Apexigen warrant agreements. At the Closing Date, the Company replaced approximately 5,815,613 Apexigen warrants with approximately 1,003,191 Pyxis Oncology warrants. The acquisition date fair value of the Replacement Warrants was $ 0.6 million, which is included in the provisional purchase price. The fair value of the Replacement Warrants was determined using the Black-Scholes option-pricing model and the following assumptions: As of August 23, 2023 Expected volatility 95.0 % Risk-free interest rate 4.36 % - 4.50 % Expected dividend yield 0.00 % Expected term (in years) 3.93 - 4.94 As of December 31, 2023, there were 344,259 warrants outstanding with an exercise price of $ 8.12 per share, 17,212 warrants outstanding with an exercise price of $ 10.14 per share and 641,720 warrants with an exercise price of $ 66.67 per share. Each of the warrants with an exercise price of $ 66.67 per share will expire on the fifth anniversary of July 29, 2022, or earlier upon redemption or liquidation. Each of the warrants with an exercise price of $ 8.12 per share and $ 10.14 per share will expire on July 30, 2028, or earlier upon redemption or liquidation. The Company may call the warrants outstanding with an exercise price of $ 10.14 per share for redemption: • in whole or in part; • at a price of $ 0.01 per warrant; • upon a minimum of 30 days’ prior written notice of redemption; and • if, and only if, the last reported closing price of the ordinary shares equals or exceeds $ 104.35 per share for any 20 trading days within a 30 -trading day period on the third trading day prior to the date on which the Company sends the notice of redemption to the warrant holders. If the Company calls these warrants for redemption, management will have the option to require all holders that wish to exercise these warrants to do so on a “cashless basis,” as described in the warrant agreement. The Replacement Warrants are equity classified because they are freestanding financial instruments that are legally detachable and separately exercisable from the equity instruments, are immediately exercisable, do not embody an obligation for the Company to repurchase its shares, permit the holders to receive a fixed number of common shares upon exercise, are indexed to the Company’s common stock and meet the equity classification criteria. In addition, such Warrants do not provide any guarantee of value or return. The Company valued the Replacement Warrants at the Acquisition Date using a relative fair value allocation method and recorded as a component of additional paid-in-capital.

Stockholders' Equity

Stockholders' Equity	12 Months Ended
	Dec. 31, 2023
Equity [Abstract]
Stockholders' Equity	14. Stockholders’ Equity Preferred Stock As of December 31, 2023, the Company had 10,000,000 authorized shares of preferred stock, with a par value of $ 0.001 per share. The board of directors has the authority, without further action by the stockholders to issue such shares of preferred stock in one or more series, to establish from time to time the number of shares to be included in each such series, and to fix the dividend, dividend rights, conversion rights, voting, redemption terms, liquidation preference and other rights, preferences and privileges of the shares. There were no issued and outstanding shares of preferred stock as of December 31, 2023 and 2022, respectively. Common Stock The Company was authorized to issue up to 190,000,000 shares of common stock as of December 31, 2023 and 2022, respectively, of which 44,754,853 and 35,110,016 shares were issued as of December 31, 2023 and 2022, respectively, and 44,754,853 and 34,958,730 shares were outstanding as of December 31, 2023 and 2022, respectively. Voting, dividend and liquidation rights of the holders of the common stock are subject to and qualified by the rights, powers and preferences of the holders of the preferred stock. Voting —Each holder of outstanding shares of common stock shall be entitled to one vote in respect of each share. Reserved Shares — The Company reserved the following shares of common stock for issuance: December 31, 2023 2022 Stock options outstanding 5,982,464 5,720,415 Unvested restricted stock awards and units 3,631,431 3,015,387 Shares reserved for future issuance 1,013,840 1,697,166 Common stock warrants 1,003,191 — Employee stock purchase plan 565,405 534,675 Total 12,196,332 10,967,643 Shelf Registration Statement and ATM Offering Program On November 1, 2022, the Company filed a registration statement on Form S-3 with the SEC for the issuance of common stock, preferred stock, warrants, debt securities, rights and units up to an aggregate of $ 250.0 million. On November 14, 2022, the registration statement was declared effective by the SEC. The registration statement includes an ATM offering program for the sale of up to $ 125.0 million of shares of the Company's common stock. Any shares offered and sold in the ATM offering will be issued pursuant to the Company’s effective shelf registration statement on Form S-3 and the related prospectus supplement. Under the ATM, the sales agents may sell shares of common stock by any method permitted by law deemed to be an “at the market offering” as defined in Rule 415(a)(4) of the Securities Act of 1933, as amended. The Company will pay the sales agents a commission rate of up to 3 % of the gross sales proceeds of any shares sold and has agreed to provide the sales agents with customary indemnification, contribution and reimbursement rights. The ATM contains customary representations and warranties and conditions to the placements of the shares pursuant thereto. During the year ended December 31, 2023, the Company completed the sale of an aggregate of 1,001,208 shares of common stock under the ATM offering program with an average gross sale price of $ 6.30 per share, resulting in gross proceeds of $ 6.3 million. The Company paid commissions of $ 0.2 million to the placement agent under the ATM offering program. See Note 20, Subsequent Events , for further discussion of sales of the Company's common stock under the ATM offering program subsequent to the balance sheet date and prior to the filing of this Annual Report on Form 10-K for the year ended December 31, 2023.

Stock-Based Compensation

Stock-Based Compensation	12 Months Ended
	Dec. 31, 2023
Share-Based Payment Arrangement [Abstract]
Stock-Based Compensation	15. Stock-Based Compensation 2022 Equity Inducement Plan On July 1, 2022, the Company’s board of directors approved the 2022 Equity Inducement Plan (the “2022 Inducement Plan”), which became effective on that date. The 2022 Inducement Plan allows the Company to make equity-based incentive awards to its officers and employees without stockholder approval pursuant to Rule 5635(c)(4) of the NASDAQ Listing Rules, or any successor rule relating to inducement awards. Unless earlier terminated by the Board, 2022 Inducement Plan will terminate on the ten th anniversary of the effective date. The Company has initially reserved 1,400,000 shares of its common stock for the issuance of awards under the 2022 Inducement Plan. As of December 31, 2023, options to purchase 828,432 shares of common stock and 138,871 restricted stock units were outstanding under the 2022 Inducement Plan and 346,443 shares remained available for future issuance under the 2022 Inducement Plan. 2021 Equity Incentive Plan On September 27, 2021, the Company’s board of directors and stockholders approved the 2021 Equity Incentive Plan (the “2021 Plan”), which became effective on October 7, 2021, when the Company’s registration statement was declared effective by the SEC. The 2021 Plan allows the Company to make equity-based and cash-based incentive awards to its officers, employees, directors and consultants. The Company has initially reserved 3,852,807 shares of its common stock for the issuance of awards under the 2021 Plan. The number of shares of common stock reserved for issuance under the 2021 Plan will automatically increase annually on the first day of each fiscal year, beginning with the fiscal year ending December 31, 2022, and continuing until (and including) the fiscal year ending December 31, 2031 by the lesser of (i) 5 % of the total number of shares of common stock outstanding on December 31st of the immediately preceding fiscal year and (ii) the number of shares as may be determined by the board of directors. On January 1, 2023, the number of shares of common stock available for issuance under the 2021 Plan increased by 1,755,501 shares as a result of the evergreen provision. The maximum number of shares of common stock that may be issued pursuant to the exercise of incentive options under the 2021 Plan is 7,705,614 . Unless earlier terminated by the Board, the 2021 Plan will terminate on the ten th anniversary of the effective date. As of December 31, 2023, options to purchase 2,037,393 shares of common stock and 2,452,500 restricted stock units were outstanding under the 2021 plan and 537,772 shares remained available for future issuance under the 2021 plan. 2019 Equity Incentive Plan In 2019, the Company established the 2019 Equity Incentive Plan (the “2019 Plan” ), under which the Company is allowed to grant options and restricted stock to its employees and non-employees. The maximum number of shares of common stock reserved for issuance under the 2019 Plan is 4,042,408 shares. Options granted under the 2019 Plan include incentive stock options that can be granted only to the Company’s employees and non-statutory stock options that can be granted to the Company’s employees, consultants, advisors and directors. The 2019 Plan also permits the Company to issue restricted stock awards. Unless earlier terminated by the Board, the 2019 Plan will terminate on the ten th anniversary of the effective date. Prior to the IPO, the exercise prices, vesting and other restrictions of the awards granted under the 2019 Plan were determined by the board of directors, except that no stock option may be issued with an exercise price less than the fair market value of the common stock at the date of the grant or have a term in excess of ten years. Options granted under the 2019 Plan are exercisable in whole or in part at any time subsequent to vesting. As of December 31, 2023, options to purchase 2,272,833 shares of common stock and 962,390 restricted stock units were outstanding under the 2019 Plan and 52,299 shares remained available for future issuance under the 2019 Plan. 2022 Equity Incentive Plan Upon the Merger, the Company assumed Apexigen's 2022 Equity Incentive Plan (the “2022 Plan”), which allows the Company to grant options and restricted stock to eligible employees and non-employees. The Company initially reserved 443,912 shares of its common stock for the issuance of awards under the 2022 Plan. The number of shares of common stock reserved for issuance under the 2022 Plan will automatically increase on January 1 of each calendar year, starting on January 1, 2023 through January 1, 2032, in an amount equal to the lesser of (i) 0.8625 % of the total number of shares of common stock outstanding on the last day of the calendar month before the date of each automatic increase, (ii) 554,890 shares, or (iii) such number of shares determined by the administrator of the 2022 Plan. On January 1, 2023, the number of shares of common stock available for issuance under the 2022 Plan increased by 554,890 shares as a result of the evergreen provision. The maximum number of shares of common stock that may be issued pursuant to the exercise of incentive options under the 2022 Plan is 597,077 . Unless earlier terminated by the Board, the 2022 Plan will terminate on the tenth anniversary of the effective date. As of December 31, 2023, options to purchase 843,806 shares of common stock and 77,670 RSUs were outstanding under the 2022 Plan and 77,326 shares remained available for future issuance under the 2022 Plan. The Company also assumed Apexigen's 2020 Equity Incentive Plan, (“2020 Plan”) as a result of the Merger. Outstanding awards granted under the 2020 Plan will remain subject to the terms of the plan, and shares underlying awards granted under such plan that are cancelled or forfeited will be available for issuance under the 2022 Plan, as applicable. 2021 Employee Stock Purchase Plan On September 27, 2021, the Company’s board of directors and stockholders approved the 2021 Employee Stock Purchase Plan (the “2021 ESPP”), which became effective on October 7, 2021, when the Company’s registration statement was declared effective by the SEC. The 2021 ESPP initially reserved and authorized the issuance of up to a total of 424,595 shares of common stock to participating employees. The number of shares of common stock reserved for issuance under the ESPP will automatically increase annually on the first day of each fiscal year, beginning with the fiscal year ending December 31, 2022, and continuing until (and including) the fiscal year ending December 31, 2031 by the lesser of (i) 110,080 shares, (ii) 1 % of the total number of shares of common stock outstanding on December 31st of the immediately preceding fiscal year and (iii) the number of shares as may be determined by the board of directors. On January 1, 2023, the number of shares of common stock available for issuance under the 2021 ESPP increased by 110,080 shares as a result of the evergreen provision. During the year ended December 31, 2023, the Company issued 79,350 shares of common stock pursuant to the ESPP. As of December 31, 2023, the authorized number of shares and shares available for issuance under the 2021 ESPP is 565,405 . Repricing of Outstanding and Unexercised Options On March 24, 2023 and in accordance with the terms of the 2019 Plan, the board of directors approved a stock option repricing (the “Repricing”) where the exercise price of each Relevant Option (as defined below) was reduced to $ 2.21 per share, the closing stock price on the date of approval by the board of directors. “Relevant Options” are all outstanding stock options as of March 24, 2023 (vested or unvested) to acquire shares of the Company’s common stock that were issued to current employees of the Company under the 2019 Plan prior to the Company’s IPO. Members of the board of directors did not participate in the Repricing. The board of directors believes that the Repricing is in the best interests of the Company, as the amended stock options will provide added incentives to retain and motivate key contributors of the Company without incurring the stock dilution resulting from significant additional equity grants or significant additional cash expenditures resulting from additional cash compensation. The board of directors also believes that the Repricing better aligns the interests of the key contributors with the goals of the Company. The option repricing resulted in incremental stock-based compensation of $ 1.1 million, of which $ 0.9 million was recorded as expense during the year ended December 31, 2023. The remaining expense will be recognized over the requisite service period in which the stock options vest. Apexigen Replacement Options and Replacement RSU Awards As described in Note 3, Acquisition of Apexigen , pursuant to the Merger Agreement , each outstanding stock option issued by Apexigen as of the Closing Date was assumed and converted into an option to acquire the Company’s common stock and each outstanding restricted stock unit awarded by Apexigen as of the Closing Date was assumed and converted into an award of the Company's common stock, on substantially similar terms and conditions as were applicable under such Apexigen equity plans. At the Closing Date, the Company issued approximately 712,181 Replacement Options and 34,500 Replacement RSU Awards to Apexigen grantholders. The acquisition date fair value of the Replacement Options was determined by the Black-Scholes option-pricing model and the acquisition date fair value attributable to the pre-combination services of $ 0.1 million is included in the purchase price, which is included in Note 3, Acquisition of Apexigen . The Replacement Options and Replacement RSU Awards will continue to vest over the remaining vesting period through the earlier of exercise, expiration or forfeiture. The number of stock options, RSUs and warrants and their respective exercise prices were adjusted by the Exchange Ratio. Stock Options Stock options granted under the 2022 Inducement Plan, 2022 Plan, 2020 Plan, 2021 Plan and 2019 Plan (together, the “Plans”) to employees generally vest over four years and expire after 10 years . The following table summarizes stock option activity for the year ended December 31, 2023 (in thousands, except share and per share amounts): Number of Options Weighted Average Weighted Average Aggregate Outstanding at January 1, 2023 5,720,415 $ 9.68 8.8 $ 72 Granted 1,078,717 1.87 Replacement Options (1) 712,181 17.57 Exercised ( 83,235 ) 1.49 Expired ( 721,598 ) 13.63 Forfeited ( 724,016 ) 8.23 Outstanding at December 31, 2023 5,982,464 $ 7.31 (1) 7.6 $ 141 (2) Options exercisable at December 31, 2023 3,300,648 $ 7.97 (1) 6.8 $ 44 (2) (1) Represents Replacement Options issued to Apexigen grantholders pursuant to the Merger Agreement. (2) The weighted average exercise price and aggregate intrinsic value as of December 31, 2023 reflect the impact of the stock option repricing discussed above. The weighted-average grant-date fair value of options granted during the years ended December 31, 2023 and 2022, was $ 1.87 and $ 3.06 per share, respectively. The aggregate intrinsic value is calculated as the difference between the exercise price of all outstanding and exercisable stock options and the fair value of the Company’s common stock of $ 1.80 per share as of December 29, 2023, the last trading day prior to the year-end 2023. The aggregate intrinsic value of stock options exercised during both of the years ended December 31, 2023 and 2022 was approximately $ 0.1 million. The Company has an aggregate $ 9.1 million of gross unrecognized stock-based compensation expense as of December 31, 2023, remaining to be amortized over a weighted average period of 1.95 years. The Company has not recognized and does not expect to recognize in the near future, any tax benefit related to employee stock-based compensation expense as a result of the full valuation allowance related to its net deferred tax assets. The Company estimated the fair value of each option on the date of grant using the Black-Scholes option-pricing model applying the range of assumptions in the following table: Year Ended December 31, 2023 2022 Expected volatility 97.11 % - 118.90 % 96.09 % - 101.66 % Risk-free interest rate 3.58 % - 5.57 % 1.60 % - 4.02 % Expected dividend yield 0.00 % 0.00 % Expected term (in years) 0.25 - 6.08 6.00 - 6.11 Restricted Stock Units Under the Plans, during the year ended December 31, 2023, the Company granted 4,200,428 RSUs to employees and non-employees. Compensation costs related to these RSUs were recorded based on the Company's stock price on the date of issuance and amortized over the service period. Additionally, the Company issued certain shares of restricted common stock awards (“RSA” ) to the employee co-founders and certain non-employee consultants in 2019. The shares of restricted common stock were issued pursuant to standalone restricted stock purchase agreements that are independent of the Plans. The shares of RSAs pursuant to standalone restricted stock purchase agreements carried a purchase price equivalent of $ 0.01 per share. As of December 31, 2023, no RSAs were outstanding and all RSAs were fully vested and converted into fully paid common stock. The following table summarizes restricted stock awards and restricted stock units for the year ended December 31, 2023: Number of Shares Weighted Average Non-vested and unsettled at January 1, 2023 3,015,387 $ 3.64 Granted 4,200,428 2.09 Replacement RSU Awards (1) 34,500 2.30 Forfeited ( 918,845 ) 3.12 Vested and settled ( 2,700,039 ) 2.91 Non-vested and unsettled at December 31, 2023 3,631,431 $ 2.51 (1) Represents Replacement RSU Awards issued to eligible Apexigen grantholders pursuant to the Merger Agreement. During the year ended December 31, 2023, the Company issued 2,476,301 shares of its common stock from the settlement of 2,700,039 restricted common stock, with the remaining shares withheld for taxes. The total fair value of restricted common stock that vested during the years ended December 31, 2023 and 2022 was $ 8.0 million and $ 0.5 million, respectively. The Company has an aggregate $ 6.8 million of gross unrecognized restricted stock-based compensation expense as of December 31, 2023, remaining to be amortized over a weighted average period of 2.48 years. Summary of Stock-Based Compensation Expense The following tables summarize the total stock-based compensation expense for the years ended December 31, 2023 and 2022, respectively (in thousands): Year Ended December 31, 2023 2022 Stock options $ 10,635 $ 11,947 Restricted stock 6,311 3,817 Total $ 16,946 $ 15,764 Year Ended December 31, 2023 2022 General and administrative $ 12,537 $ 10,548 Research and development 4,409 5,216 Total $ 16,946 $ 15,764 Total stock-based compensation expense for stock options includes expense related to the 2021 ESPP of less than $ 0.1 million and $ 0 for the years ended December 31, 2023 and December 31, 2022, respectively.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2023
Income Tax Disclosure [Abstract]
Income Taxes	16. Income Taxes During the years ended December 31, 2023 and 2022, the Company recorded no current or deferred income tax expenses or benefits as the Company has incurred losses since inception and has provided a full valuation allowance against its deferred tax assets. The Company has recorded a current state income tax expense for Massachusetts in the amount of less than $ 0.1 million for the years ended December 31, 2023 and 2022. A reconciliation of the expected income tax benefit computed using the federal statutory income tax rate to the Company’s effective income tax rate is as follows for the years ended December 31, 2023 and 2022: Year Ended December 31, 2023 2022 Income tax computed at federal statutory rate % 21.0 % 21.0 % State taxes, net of federal benefit 2.1 % 5.6 % Share based compensation - 3.5 % - 1.7 % Change in valuation allowance - 19.3 % - 26.6 % Change in state apportionment 0.0 % - 0.1 % Provision to tax return differences - 3.0 % - 0.4 % Research and development credit carryovers 3.0 % 1.7 % Permanent differences - 0.3 % 0.5 % Effective income tax rate % 0.0 % 0.0 % The Company's effective tax rate was 0 % for the years ended December 31, 2023 and 2022, as a result of the valuation allowance that eliminates the company's net deferred tax assets. Deferred income taxes reflect the net tax effects of temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes. Significant components of the Company’s net deferred tax assets as of December 31, 2023 and 2022 are as follows (in thousands): Year Ended December 31, 2023 2022 Deferred tax assets: Net operating losses $ 67,569 $ 13,108 Tax credit carryforwards 10,689 3,674 Derivative 1,319 1,455 Stock-based compensation 3,204 2,645 Reserves and accruals 1,156 1,105 Capitalized research expenditures 23,423 20,059 License fees 13,555 14,235 Operating lease liability 3,996 5,107 Deferred revenue 2,027 — Intangibles — 69 Other 183 29 Total gross deferred tax assets before valuation allowance 127,121 61,486 Less: valuation allowance ( 119,504 ) ( 57,812 ) Total deferred tax assets $ 7,617 $ 3,674 Deferred tax liabilities: Operating lease ROU assets ( 3,459 ) ( 3,674 ) Intangibles ( 6,322 ) — Total deferred tax liabilities ( 9,781 ) ( 3,674 ) Net deferred tax liabilities $ ( 2,164 ) $ — As of December 31, 2023, the Company's federal and state net operating losses in the United States were $ 56.4 million ($ 268.5 million before tax) and $ 11.2 million ($ 167.4 million before tax) respectively. The federal net operating loss carryforward generated in the United States after tax year 2017 can be carried forward indefinitely but may be subject to annual usage limitations to the extent certain substantial changes in the entity's ownership occur. The federal net operating loss carryforward relating to tax years prior to 2017 of $ 5.9 million ($ 28.3 million before tax), acquired with Apexigen, begin to expire in 2033 . The state net operating loss carryforwards begin expiring in 2035 . In addition, as of December 31, 2023, the Company had $ 7.8 million and $ 3.6 million of federal and state credit carryovers which begin to expire in 2030 . These loss and credit carryforwards are subject to review and possible adjustment by the relevant taxing authorities. The Company assesses the realizability of the deferred tax assets at each balance sheet based on the available positive and negative evidence in order to determine the amount which is more likely than not to be realized and records a valuation allowance as necessary. Due to the Company's cumulative loss position which provides significant negative evidence, which is difficult to overcome, the Company has recorded a valuation allowance of $ 119.5 million as of December 31, 2023, representing the portion of the deferred tax asset that is not more likely than not to be realized. For the years ended December 31, 2023 and 2022, the valuation allowance for deferred tax assets increased by $ 61.7 million and $ 32.1 million, respectively. The amount of the deferred tax asset considered realizable, could be adjusted for future factors that would impact the assessment of the objective and subjective evidence. The Company will continue to assess the realizability of deferred tax assets at each balance sheet date in order to determine the proper amount, if any, required for a valuation allowance. The U.S. tax attributes may be subject to an annual limitation under Section 382 of the Internal Revenue Code of 1986 (the “Code”), and similar state provisions if the Company experiences one or more ownership changes, which would limit the amount of the tax attributes that can be utilized to offset future taxable income. In general, an ownership change as defined by Section 382, results from the transactions increasing ownership of certain stockholders or public groups in the stock of the corporation of more than fifty percentage points over a three-year period. If a change in ownership occurs in the future, the net operating loss and research and development credit carryforwards could be eliminated or restricted. If eliminated, the related asset would be removed from the deferred tax asset schedule with a corresponding reduction in the valuation allowance. Due to the existence of the valuation allowance, limitations created by future ownership changes, if any, will not impact the Company’s effective tax rate. The Company is subject to tax and will continue to file federal income tax returns in the United States as well as in certain state and local jurisdictions. The Company is subject to tax examinations for tax years ended December 31, 2020 and forward in all applicable income tax jurisdictions. Tax audits and examinations can involve complex issues, interpretations and judgments. The resolution of matters may span multiple years particularly if subject to litigation or negotiation. The Company believes that it has appropriately recorded its tax position using reasonable estimates and assumptions, however the potential tax benefits may impact the results of operations or cashflows in the period of resolution, settlement, or when the statutes of limitations expire. The Company has recorded reserves related to unrecognized tax benefits on historical positions taken by Apexigen in periods before the merger. No interest or penalties have been calculated on the reserves for unrecognized tax benefits due to taxable losses in the years in which the benefits were recorded. The Company does not believe that it is reasonably possible that the resolution of tax exposures within the next twelve months would have a material impact on the consolidated financial statements as of December 31, 2023. A reconciliation of the beginning and ending amounts of unrecognized tax benefits is as follows (in thousands): Year Ended December 31, 2023 2022 Gross unrecognized tax benefit at January 1 $ — $ — Additions for positions taken during a prior period 2,003 — Gross unrecognized tax benefit at December 31 $ 2,003 $ —

Net Loss per Share

Net Loss per Share	12 Months Ended
	Dec. 31, 2023
Earnings Per Share [Abstract]
Net Loss per Share	17. Net Loss per Share The Company’s potentially dilutive securities, which include restricted stock, and stock options, have been excluded from the computation of diluted net loss per share as the effect would be to reduce the net loss per share. Therefore, the weighted-average number of common shares outstanding used to calculate both basic and diluted net loss per share attributable to common stockholders is the same. Basic and diluted net loss per share was calculated as follows (in thousands, except share and per share amounts): Year Ended December 31, 2023 2022 Numerator: Net loss $ ( 73,790 ) $ ( 120,717 ) Denominator: Weighted-average common shares outstanding, basic and diluted 39,904,603 33,033,081 Net loss per share, basic and diluted $ ( 1.85 ) $ ( 3.65 ) The following potentially dilutive securities have been excluded from the calculation of diluted net loss per common share due to their anti-dilutive effect: December 31, 2023 2022 Stock options outstanding 5,982,464 5,720,415 Unvested restricted stock awards and units 3,631,431 3,015,387 Shares reserved for future issuance 1,013,840 1,697,166 Common stock warrants 1,003,191 — Employee stock purchase plan 565,405 534,675 Total 12,196,332 10,967,643

Related Parties

Related Parties	12 Months Ended
	Dec. 31, 2023
Related Party Transactions [Abstract]
Related Parties	18. Related Parties The Company was founded out of Dr. Thomas Gajewski’s laboratory at the University of Chicago. In 2020, the Company entered into the License Agreement with the University of Chicago, as well as a sponsored research agreement. The Company incurred expenses of $ 0.2 million and $ 0.3 million during the years ended December 31, 2023 and 2022, respectively, with regards to the University License Agreement. Refer to Note 4, Licensing Agreements, for additional discussion. Pfizer owns more than 10 % of the Company and is considered the principal owner of the Company. The Company incurred expenses of $ 0 and $ 17.3 million during the years ended December 31, 2023 and 2022, respectively, with regards to the Pfizer A&R License Agreement. Refer to Note 4, Licensing Agreements , for additional discussion. The Company and Alloy formed a joint venture company, Voxall Therapeutics, LLC (“Voxall”) to leverage the Company’s technology and Alloy’s ATX-Gx™ platform and antibody discovery services. The Company and Alloy contributed $ 50 thousand each to Voxall along with certain license in 2021. The Company did no t incur expenses during the years ended December 31, 2023 and 2022 with regards to Voxall. Refer to Note 5, Joint Venture , and Note 20, Subsequent Events , for additional discussion.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2023
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	19. Commitments and Contingencies Legal Proceedings From time to time, the Company may become involved in various legal proceedings that arise in the ordinary course of business. The Company is not currently a party to any material legal proceedings and is not aware of any pending or threatened legal proceeding against it that the Company believes could have an adverse effect on its business, operating results or financial condition. Commitments In the normal course of business, the Company enters into agreements with various third parties for clinical trials, preclinical research studies and testing, manufacturing and other services and products for operating purposes, which are generally cancellable by the Company at any time, subject to payment of remaining obligations under binding purchase orders and, in certain cases, nominal early-termination fees. These commitments are not deemed significant.

Subsequent Event

Subsequent Event	12 Months Ended
	Dec. 31, 2023
Subsequent Events [Abstract]
Subsequent Event	20. Subsequent Event ATM Offering Program On January 30, 2024, the Company completed the sale of an aggregate of 3,600,000 shares of common stock under the ATM offering program, with an average sale price of $ 3.00 per share, resulting in gross proceeds of $ 10.8 million, before deducting placement agent fees under the ATM offering program. The issuance and sale of common stock under the ATM offering program is made pursuant to our registration statement on Form S-3 (file number 333-268100), which was declared effective by the SEC on November 14, 2022. Dissolution of Voxall Joint Venture In February 2024, the Board of Directors of Voxall approved to dissolve the joint venture. The mutual decision to dissolve comes as a result of the corporate reorganization announced in November 2023, as the Company continues to align its resources and refocus its efforts on its progressing the clinical trials. Upon dissolution, Alloy retained rights to certain intellectual property and may develop and commercialize at its sole discretion. Any amounts owed by Voxall to either the Company or Alloy were discharged in their entirety without further liability upon the dissolution. The Company will absorb its portion of the cumulative losses, which is limited to its initial investment in the joint venture of $ 50 thousand and which was fully provided for in 2021. Private Placement Funding On February 26, 2024, the Company entered into a securities purchase agreement (the “Securities Purchase Agreement”) for a private placement (the “Private Placement”) with certain institutional and accredited investors (each, a “Purchaser” and collectively, the “Purchasers”). Pursuant to the Securities Purchase Agreement, the Company agreed to issue and sell to the Purchasers an aggregate of (i) 8,849,371 shares (the “Shares”) of the Company’s common stock, par value $ 0.001 per share (the “Common Stock”), at a purchase price of $ 4.78 per share, and (ii) pre-funded warrants (the “Pre-Funded Warrants”) to purchase up to an aggregate of 1,611,215 shares of Common Stock (the “Pre-Funded Warrant Shares”) at a purchase price of $ 4.779 per Pre-Funded Warrant, which represents the per share purchase price of the Shares less the $ 0.001 per share exercise price for each Pre-Funded Warrant. The Pre-Funded Warrants will be exercisable at any time after the date of issuance and will not expire. The Private Placement closed on February 29, 2024. The Company received gross proceeds from the Private Placement of approximately $ 50 million, before deducting placement agent fees and offering expenses directly related to the Private Placement.

Basis of Presentation and Sum_2

Basis of Presentation and Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2023
Accounting Policies [Abstract]
Nature of Business	Nature of Business Pyxis Oncology, Inc. (the “Company”), a Delaware corporation, was founded in June 2018 and launched its operations in July 2019. The Company is a clinical stage company focused on defeating difficult-to-treat cancers. The Company is efficiently building next-generation therapeutics that hold the potential for mono and combination therapies. The Company's therapeutic candidates are designed to kill tumor cells and to address the underlying pathologies created by cancer that enable its uncontrollable proliferation and immune evasion. The Company's antibody-drug conjugates (“ADCs”) and immuno-oncology (“IO”) programs employ novel and emerging strategies to target a broad range of solid tumors resistant to current standards of care. The Company has one operating segment. The Company’s chief operating decision maker, its Chief Executive Officer, manages the Company’s operations on a consolidated basis for the purposes of assessing performance and allocating resources.
Basis of Presentation	Basis of Presentation The Company’s fiscal year ends on December 31 and its first three quarters end on March 31, June 30 and September 30. The accompanying consolidated financial statements are prepared in conformity with accounting principles generally accepted in the United States of America (“GAAP”). Any reference in these notes to applicable guidance is meant to refer to the authoritative GAAP as found in the Accounting Standards Codification (“ASC”) and Accounting Standards Updates (“ASU”) of the Financial Accounting Standards Board (“FASB”). The consolidated financial statements include the Company and its wholly-owned subsidiaries. All intercompany balances and transactions have been eliminated upon consolidation. The Company is an “emerging growth company,” as defined in the Jumpstart Our Business Startups Act of 2012 (the “JOBS Act”). Section 107(b) of the JOBS Act provides that an emerging growth company can take advantage of an extended transition period for complying with new or revised accounting standards. Thus, an emerging growth company can delay the adoption of certain accounting standards until those standards would otherwise apply to private companies. The Company has irrevocably elected not to avail itself of this extended transition period, and, as a result, the Company will adopt new or revised accounting standards on the relevant dates on which adoption of such standards is required for other public companies.
Liquidity	Liquidity As of December 31, 2023, the Company had an accumulated deficit of $ 286.2 million. The Company has incurred losses and negative cash flows from operations since inception, including net losses of $ 73.8 million and $ 120.7 million for the years ended December 31, 2023 and 2022, respectively. The Company has not generated any revenues from product sales to date and does not anticipate generating any revenues from product sales unless and until it successfully completes development and obtains regulatory approval for its current or any future product candidates. The Company expects that its operating losses and negative cash flows will continue for the foreseeable future as the Company continues to expand its research and development programs and develop its product candidates. The Company currently expects that its existing cash, cash equivalents and short-term investments of $ 119.3 million as of December 31, 2023 will fund its operating expenses and capital requirements at least twelve months from the date these audited consolidated financial statements are issued. Additional funding may be necessary to fund future clinical and preclinical activities. The Company plans to continue to fund its losses from operations and capital funding needs through public or private equity, convertible or debt financing 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.
Use of Estimates	Use of Estimates The preparation of consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, expense, and related disclosures. The Company regularly evaluates estimates and assumptions related to assets, liabilities, stock-based compensation, operating leases, assessment of the useful lives of property and equipment, marketable debt securities, fair value of intangible assets and research and development costs, including clinical trial accruals. The Company bases its estimates and assumptions on historical experience and on various other factors that it believes to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities that are not readily apparent from other sources. Actual results could differ from those estimates and there may be changes to management’s estimates in future periods.
Risks and Uncertainties	Risks and Uncertainties The Company is subject to risks common to early-stage companies in the biopharmaceutical industry including, but not limited to, uncertainties related to commercialization of products, regulatory approvals, dependence on key suppliers for active ingredients and third-party service providers such as contract development and manufacturing organizations (“CDMOs”), protection of intellectual property rights and the ability to make milestone, royalty or other payments due under any license, collaboration or supply agreements.
Concentration of Credit Risks	Concentration of Credit Risks Financial instruments which potentially subject the Company to significant concentration of credit risk consist of cash and cash equivalents, restricted cash and short-term investments. The Company invests its excess cash primarily in money market funds and highly liquid U.S. Treasury securities. The Company has adopted an investment policy that includes guidelines relative to credit quality, diversification and maturities to preserve principal and liquidity.
Cash and Cash Equivalents	Cash and Cash Equivalents The Company considers all short term, highly liquid investments with original maturities of 90 days or less to be cash equivalents. Cash equivalents consist primarily of money market funds as of December 31, 2023 and 2022.
Investments	Investments Short-term investments consist of U.S. Treasury securities with original maturities greater than three months. The Company may sell investments at any time for use in current operations even if the investments have not yet reached maturity. As a result, the Company classifies its investments as current assets. All investments have been classified as available-for-sale marketable debt securities. Marketable debt securities are recorded at fair value, with unrealized gains and losses, net of tax, included as a component of accumulated other comprehensive income (loss) in stockholders’ equity and a component of total comprehensive loss in the consolidated statements of operations and comprehensive loss, until realized. The fair value of these securities is determined based upon quoted market prices at period end. Premiums paid or discounts received at the time of purchase of marketable securities, are amortized to interest and investment income over the terms of the related securities. Realized gains and losses are included in earnings and are derived using the specific identification method for determining the cost of securities sold. At each reporting date the Company will evaluate available-for-sale marketable debt securities in an unrealized loss position, using the discounted cash flow model, to determine whether the unrealized loss or any potential credit losses should be recognized in net loss. For available-for-sale marketable debt securities in an unrealized loss position, the Company will assess (i) whether it intends to sell, or (ii) it is more likely than not that it will be required to sell the security before recovery of its amortized cost basis. If the aforementioned criteria is met, such marketable debt security’s amortized cost basis will be written down to its fair value through earnings along with any existing allowance for credit losses. For available-for-sale marketable debt securities that do not meet this criteria, the Company will evaluate whether the decline in fair value has resulted from credit losses or other factors. In making this assessment, the Company considers the severity of the impairment, any changes in interest rates, underlying credit ratings, and forecasted recovery, among other factors. The credit-related portion of unrealized losses, and any subsequent improvements, are recorded as an allowance in interest income. There have been no impairment or credit losses recognized during the periods presented in the accompanying consolidated statements of operations and comprehensive loss.
Fair Value Measurements	Fair Value Measurements Certain assets and liabilities are carried at fair value under GAAP. Fair value is defined as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principle or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. Valuation techniques used to measure fair value must maximize the use of observable inputs and minimize the use of unobservable inputs. Financial assets and liabilities carried at fair value are to be classified and disclosed in one of the following three levels of the fair value hierarchy, the first two are considered observable and the last is considered unobservable: Level 1 —Unadjusted quoted prices in active markets that are accessible at the measurement date for identical, unrestricted assets or liabilities; Level 2 —Quoted prices in markets that are not considered to be active or financial instrument valuations for which all significant inputs are observable, either directly or indirectly; and Level 3 —Prices or valuations that require inputs that are both significant to the fair value measurement and unobservable. To the extent that the valuation is based on models or inputs that are less observable or unobservable in the market, the determination of fair value requires more judgment. Accordingly, the degree of judgment exercised by the Company in determining fair value is greatest for instruments categorized in Level 3.
Property and Equipment, net	Property and Equipment, net Property and equipment are recorded at cost less accumulated depreciation and amortization. Depreciation and amortization expense is recognized using the straight-line method over the estimated useful lives of the related assets as follows: Estimated Useful Laboratory equipment 3 Furniture and office equipment 3 Leasehold improvements Shorter of remaining life Construction in process N/A Depreciation and amortization expense is included in research and development and general and administrative expenses. Major additions and upgrades are capitalized; maintenance and repairs, which do not improve or extend the life of the respective assets, are expensed as incurred. Upon retirement or sale, the cost of assets disposed of, and the related accumulated depreciation and amortization are removed from the respective accounts and any resulting gain or loss is included in income (loss) from operations.
Impairment of Long-Lived Assets	Impairment of Long-Lived Assets The Company evaluates its long-lived assets, which consist of property and equipment and operating lease right-of-use assets, whenever events or changes in circumstances indicate that the carrying value of an asset may not be recoverable. Factors that the Company considers in deciding when to perform an impairment review include significant underperformance of the business in relation to expectations, significant negative industry or economic trends, and significant changes or planned changes in the use of the assets. Management then determines whether the remaining useful life continues to be appropriate, or whether there has been an impairment of long-lived assets based primarily upon whether expected future undiscounted cash flows are sufficient to support the assets’ recovery. Recoverability of these assets is measured by comparison of the carrying amount of the asset to the future undiscounted cash flows the asset is expected to generate. If the asset is considered to be impaired, the amount of any impairment is measured as the difference between the carrying value and the fair value of the impaired asset. The Company recognized no impairment losses for the years ended December 31, 2023 and 2022.
Business Combinations	Business Combinations The Company determines whether a transaction or other event is a business combination by determining whether the assets acquired and liabilities assumed constitutes a business. Business combinations are accounted for by applying the acquisition method as set out by ASC 805, Business Combinations (“ASC 805”). The acquisition method of accounting requires the acquirer to recognize and measure all identifiable assets acquired, liabilities assumed and any noncontrolling interest in the acquiree at their acquisition-date fair values, with certain exceptions for specific items. Goodwill is measured as the excess of the consideration transferred in the business combination over the net acquisition date amounts of the identifiable assets acquired and the liabilities assumed. Alternatively, if the acquisition date amounts of the identifiable assets acquired and the liabilities assumed exceeds the consideration transferred, a gain on bargain purchase is recognized in the consolidated statements of operations and comprehensive loss. The consideration transferred in a business combination is measured as the sum of the fair values of the assets transferred, the liabilities incurred to former owners of the target and the equity interests issued. The results of operations of businesses acquired by the Company are included in the Company’s consolidated statements of operations and comprehensive loss from the respective acquisition date. Where the acquirer exchanges its share-based payment awards for awards held by grantees of the acquiree, such exchanges are treated as a modification of share-based payment awards and are referred to as replacement awards. The replacement awards are measured as of the acquisition date and the portion of the fair-value-based measure of the replacement award that is attributable to pre-combination service is considered part of the consideration transferred. For awards with service-based vesting conditions only, the amount attributable to pre-combination service is the fair-value-based measure of the acquiree award multiplied by the ratio of the employee’s pre-combination service period to the greater of the total service period or the original service period of the acquiree award. Acquisition-related costs, including advisory, legal and other professional fees and administrative fees are expensed as incurred except for the costs of issuing equity securities, which are recognized as a reduction to the amounts recognized in the consolidated statements of stockholders' equity for the respective equity issuance.
Intangible Assets, Net	Intangible Assets, Net Acquired In-Process Research & Development The Company’s indefinite-lived intangible assets consist of in-process research and development (“IPR&D”), which were acquired in connection with the acquisition of Apexigen. IPR&D represents the fair value assigned to research and development projects acquired which are in-process, but not yet completed at the time of acquisition. The primary basis for determining the completion of these projects is obtaining regulatory approval to market the underlying products in an applicable geographic region. The Company classifies IPR&D acquired in a business combination as an indefinite-lived intangible asset until the associated research and development efforts are either completed or abandoned. IPR&D becomes definite-lived upon the completion or abandonment of the associated research and development efforts. Indefinite-lived intangible assets are not amortized, but evaluated for impairment on an annual basis or more frequently if an indicator of impairment is identified. All research and development costs incurred subsequent to the acquisition of IPR&D are expensed as incurred. Definite-Lived Intangible Assets Definite-lived intangible assets are recorded at cost, net of accumulated amortization, and, if applicable, impairment charges. Definite-lived intangible assets consist of retained royalty rights under certain Apexigen agreements. The useful lives of these royalty rights are 3- and 13-years, which were determined based on the terms and conditions underlying the licensing agreements and the expected uses of the assets by the Company. Amortization of defined-lived intangible assets is recorded over the assets’ estimated useful lives on a straight-line basis and is included as part of “Research and development” within the accompanying consolidated statements of operations and comprehensive loss.
Impairment of Intangible Assets	Impairment of Intangible Assets The Company evaluates its intangible assets, including both acquired IPR&D and definite-lived intangible assets, for impairment at least annually and whenever events or changes in circumstances indicate that the carrying value of an asset may not be recoverable. Factors that the Company considers in deciding when to perform an impairment review include significant underperformance of the business in relation to expectations, significant negative industry or economic trends, and significant changes or planned changes in the use of the assets. If the projected undiscounted cash flows of the intangible asset are less than the carrying amount, the intangible asset is written down to its fair value in the period in which the impairment occurs. The Company recognized no impairment losses for the year ended December 31, 2023. The Company had no intangible assets during the year ended December 31, 2022.
Leases	Leases Operating lease right-of-use (“ROU”) assets represent the Company’s right to use an underlying asset during the lease term, and operating lease liabilities represent the Company’s obligation to make lease payments arising from the lease. Operating lease ROU assets and lease liabilities are initially recognized and measured based on the present value of the future fixed lease payments over the expected lease term at the commencement date calculated using the Company’s incremental borrowing rate applicable to the lease asset, unless the implicit rate is readily determinable. The Company determines the lease term as the non-cancelable period of the lease and may include options to extend or terminate the lease when it is reasonably certain that the Company will exercise that option. Operating lease ROU assets also include any initial direct costs incurred and any lease payments made on or before the lease commencement date, less lease incentives received. Operating lease ROU assets are subsequently measured throughout the lease term at the carrying amount of the lease liability, plus initial direct costs, plus (minus) any prepaid (accrued) lease payments, less the unamortized balance of lease incentives received. Leases with a term of 12 months or less are not recognized on the consolidated balance sheets. Lease expense for minimum lease payments is recognized on a straight-line basis over the lease term. Variable lease costs such as common area costs and other operating costs are expensed as incurred. The Company accounts for lease and non-lease components as a single lease component for all its facilities leases.
Investment in Joint Venture	Investment in Joint Venture Investment in the Company’s joint venture is accounted for using the equity method of accounting. The Company applies the equity method of accounting to investments when the Company has significant influence, but not controlling interest in the investee. Judgment regarding the level of influence over equity method investment includes considering key factors such as ownership interest, representation on the board of directors, participation in policy-making decisions and material intercompany transactions. Under the equity method, investments are initially recorded at cost and are adjusted for dividends, distributed and undistributed earnings and losses, and additional investments. In the event the Company’s share of a joint venture’s cumulative losses exceeds the Company’s investment balance, the balance is reported at zero value until proportionate income exceeds the losses. The Company assesses investments for impairment whenever events or changes in circumstances indicate that the carrying value of an investment may not be recoverable.
Warrants	Warrants The Company accounts for warrants to purchase shares of its common stock in accordance with the guidance in ASC 480, Distinguishing Liabilities from Equity (“ASC 480”) and ASC 815, Derivatives and Hedging (“ASC 815”). The Company classifies warrants issued for the purchase of shares of its common stock as either equity or liability instruments based on an assessment of the specific terms and conditions of each respective contract. The assessment considers whether the warrants are freestanding financial instruments or embedded in a host instrument, whether the warrants meet the definition of a liability pursuant to ASC 480, whether the warrants meet the definition of a derivative under ASC 815, and whether the warrants meet all of the requirements for equity classification under ASC 815. This assessment, which requires the use of professional judgment, is conducted at the time of warrant issuance and as of each subsequent quarterly period end date while the warrants are outstanding. For issued or modified warrants that meet all of the criteria for equity classification, the warrants are required to be recorded as a component of equity at the time of issuance. For issued or modified warrants that do not meet all the criteria for equity classification, the warrants are required to be recorded as liabilities at their initial fair value on the date of issuance, and each balance sheet date thereafter. Changes in the estimated fair value of the warrants classified as liabilities are recognized as a non-cash gain or loss in the consolidated statements of operations and comprehensive loss.
Contingencies	Contingencies The Company, from time to time, may be a party to various disputes and claims arising from normal business activities. The Company continually assesses disputes and claims including resulting litigation to determine if an unfavorable outcome would lead to a probable loss or reasonably possible loss which could be estimated. The Company accrues for all contingencies at the earliest date at which the Company deems it probable that a liability has been incurred and the amount of such liability can be reasonably estimated. If the estimate of a probable loss is a range and no amount within the range is more likely than another, the Company accrues the minimum of the range. In the cases where the Company believes that a reasonably possible loss exists, the Company discloses the facts and circumstances of the contingencies, including an estimable range, if possible.
Revenue Recognition	Revenue Recognition The Company recognizes revenue based on guidance under ASC 606, Revenue from Contracts with Customers (“ASC 606”). Under ASC 606, revenue is recognized when the customer obtains control of the promised goods or services, at an amount that reflects the consideration the Company expects to receive in exchange for those goods or services. The Company has not commenced sales of its drug candidates and does not have any products approved for marketing as of December 31, 2023. The Company may also earn contingent fees, including milestone payments, based on counterparty performance and royalties on sales, from collaborations and other out-license arrangements. The Company recognizes milestone payments as revenue once the underlying events are probable of being met and there is not a significant risk of reversal. The Company recognizes sales-based royalties as revenue when the underlying sales occur and there are no constrains to recognize the revenue for such sales-based royalties .
Research and Development Expenses	Research and Development Expenses The Company expenses research and development costs as incurred. The Company’s research and development expenses consist primarily of license fees to acquire intellectual property which does not meet the definition of intangible assets and costs incurred in performing research and development activities, including personnel-related expenses such as salaries, stock-based compensation and benefits, facilities costs, depreciation as well as external costs from third parties who conduct research and development activities (including manufacturing) on behalf of the Company. The Company accrues expenses related to development activities performed by third parties based on an evaluation of services received and efforts expended pursuant to the terms of the contractual arrangements. Payments under some of these contracts depend on preclinical and/or clinical trial milestones. There may be instances in which payments made to the Company’s vendors will exceed the level of services provided and result in a prepayment of expenses. In accruing service fees, the Company estimates the time period over which services will be performed and the level of effort to be expended in each period. If the actual timing of the performance of services or the level of effort varies from the estimate, the Company adjusts the accrual or prepaid expense accordingly.
Stock-Based Compensation	Stock-Based Compensation The Company maintains an equity incentive plan as a long-term incentive for employees, consultants and directors. The Company accounts for all stock-based awards granted to employees and non-employees based on their fair value on the date of the grant and recognizes compensation expense for those awards over the requisite service period, which is generally the vesting period of the respective award. The grant date fair value of the stock-based awards with graded vesting is recognized on a straight-line basis over the requisite service period. The Company recognizes forfeitures related to stock-based compensation awards as they occur and reverses any previously recognized compensation cost associated with forfeited awards in the period the forfeiture occurs. The Company classifies stock-based compensation expense in the consolidated statements of operations and comprehensive loss in the same manner in which the award recipients’ payroll costs are classified or in which the award recipients’ service payments are classified. The Company values its stock options with service conditions using the Black-Scholes option-pricing model. The Company uses certain assumptions to determine fair value of the stock options pursuant to the Black-Scholes option-pricing model, including the expected life of the award, volatility of the underlying shares, the risk-free interest rate, expected dividend yield and the fair value of the Company’s common stock. Since the Company lacks sufficient historical option exercise data to provide a reasonable basis upon which to estimate the expected term, the Company uses the simplified method described in the U.S. Securities and Exchange Commission's ("SEC") Staff Accounting Bulletin No. 107, Share-Based Payment (“SAB 107”), to determine the expected life of the option grants. The Company lacks sufficient company-specific historical and implied volatility information. Therefore, the Company estimates the expected stock volatility based on the historical volatility of a publicly traded set of peer companies. The risk-free interest rate is based on the rates paid on securities issued by the U.S. Treasury with a term approximating the expected life of the equity award. As the Company has never paid and does not anticipate paying cash dividends on its common stock, the expected dividend yield is considered as zero.
Income Taxes	Income Taxes The Company accounts for income taxes in accordance with FASB ASC 740, Income Taxes (“ASC 740”), which requires the use of the asset and liability method of accounting for income taxes. Under this method, deferred tax assets and liabilities are determined on the basis of the differences between amounts in the consolidated financial statements and the tax bases 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 in income tax (benefit) expense in the consolidated statements of operations and comprehensive loss in the period that includes the enactment date. The Company recognizes deferred tax assets to the extent that it believes these assets are more likely than not to be realized. In making such a determination, the Company considers all available positive and negative evidence, including future reversals of existing taxable temporary differences, projected future taxable income, tax-planning strategies and results of recent operations. If the Company determines that it would be able to realize its deferred tax assets in the future in excess of its net recorded amount, the Company would make an adjustment to the deferred tax asset valuation allowance, which would reduce the provision for income taxes. Changes in recognition or measurement are reflected in the period in which the change in judgment occurs. When uncertain tax positions exist, the Company recognizes the tax benefit of tax positions to the extent that the benefit will more likely than not be realized. The determination as to whether the tax benefit will more likely than not be realized is based upon the technical merits of the tax position as well as consideration of the available facts and circumstances.
Net Loss per Share	Net Loss per Share Basic net income (loss) per share attributable to common stockholders is computed by dividing net income (loss) attributable to common stockholders by the weighted average number of common shares outstanding for the period. Diluted net income (loss) per share attributable to common stockholders is computed by dividing the diluted net income (loss) attributable to common stockholders by the diluted weighted average number of common shares outstanding for the period, including potential dilutive common shares. In periods in which the Company reports a net loss, all common stock equivalents are deemed anti-dilutive such that basic net loss per common share and diluted net loss per common share are equivalent. Potentially dilutive common stock has been excluded from the diluted net loss per common share computations in all periods presented because such securities have an anti-dilutive effect on net loss per common share due to the Company’s net loss. There are no reconciling items used to calculate the weighted-average number of total common stock outstanding for basic and diluted net loss per common share data.
Recently Adopted Accounting Pronouncements	Recently Adopted Accounting Pronouncements In June 2016, the FASB issued ASU 2016-13, Financial Instruments-Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments (“ASU 2016-13”), which requires the measurement and recognition of expected credit losses for financial assets held at amortized cost. ASU 2016-13 replaces the existing incurred loss impairment model with an expected loss model that requires the use of forward-looking information to calculate credit loss estimates. It also eliminates the concept of other-than-temporary impairment and requires credit losses on available-for-sale debt securities to be recorded through an allowance for credit losses instead of as a reduction in the amortized cost basis of the securities. For "emerging growth companies", ASU 2016-13 is effective for fiscal years beginning after December 15, 2022, and interim periods within those fiscal years. On January 1, 2023 , the Company adopted ASU 2021-08, which did no t have a material effect on the Company's financial position, results of operations, or cash flows. In October 2021, the FASB issued ASU 2021-08, Business Combinations (Topic 805): Accounting for Contract Assets and Contract Liabilities from Contracts with Customers (“ASU 2021-08”), which amends the accounting related to contract assets and liabilities acquired in business combinations. ASU 2021-08 requires that entities recognize and measure contract assets and contract liabilities acquired in a business combination in accordance with ASC Topic 606, Revenue from Contracts with Customers . ASU 2021-08 is effective for fiscal years beginning after December 15, 2022, including interim periods within those fiscal years, and should be applied prospectively to businesses combinations occurring on or after the effective date of the amendment. Early adoption is permitted, including adoption in an interim period. On January 1, 2023 , the Company adopted ASU 2021-08, which did no t have a material effect on the Company's financial position, results of operations, or cash flows. Recently Issued Accounting Pronouncements In August 2020, the FASB issued ASU 2020-06, Debt – Debt with Conversion and Other Options (Subtopic 470-20) and Derivatives and Hedging – Contracts in Entity’s Own Equity (Subtopic 815-40) (“ASU 2020-06”). ASU 2020-06 revises the guidance on calculating earnings per share, requiring use of the if-converted method for all convertible instruments and rescinding an entity’s ability to rebut the presumption of share settlement for instruments that may be settled in cash or other assets. As an "emerging growth company", ASU 2020-06 will become effective for the Company for fiscal years beginning after December 15, 2023, and early adoption is permitted. The Company is currently evaluating the new standard and expects it to have no material impact on the Company's consolidated financial statements and related disclosures. In November 2023, the FASB issued Accounting Standards Update No. 2023-07, Segment Reporting - Improvements to Reportable Segment Disclosures . The amendments require disclosure of incremental segment information on an annual and interim basis. The amendments also require companies with a single reportable segment to provide all disclosures required by this amendment and all existing segment disclosures in Accounting Standards Codification 280, Segment Reporting . The amendments are effective for fiscal years beginning after December 15, 2023, and interim periods beginning after December 15, 2024. The Company is currently evaluating the new standard and expects it to have no material impact on the Company's consolidated financial statements and related disclosures. In December 2023, the FASB issued Accounting Standards Update No. 2023-09, Income Taxes - Improvements to Income Tax Disclosures . The amendments require (i) enhanced disclosures in connection with an entity's effective tax rate reconciliation and (ii) income taxes paid disaggregated by jurisdiction. The amendments are effective for annual periods beginning after December 15, 2024. The Company is currently evaluating the new standard and expects it to have no material impact on the Company's consolidated financial statements and related disclosures.

Basis of Presentation and Sum_3

Basis of Presentation and Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2023
Accounting Policies [Abstract]
Schedule of Estimated Useful Lives of Property and Equipment	Property and equipment are recorded at cost less accumulated depreciation and amortization. Depreciation and amortization expense is recognized using the straight-line method over the estimated useful lives of the related assets as follows: Estimated Useful Laboratory equipment 3 Furniture and office equipment 3 Leasehold improvements Shorter of remaining life Construction in process N/A

Acquisition of Apexigen (Tables

Acquisition of Apexigen (Tables)	12 Months Ended
	Dec. 31, 2023
Business Combinations [Abstract]
Summary of Acquisition Date Fair Value of Consideration Transferred	The following table summarizes the acquisition date fair value of the consideration transferred for Apexigen (in thousands, except share and per-share information): Fair value of Pyxis Oncology common stock issued to Apexigen stockholders (i) $ 9,970 Fair value of replacement options and RSUs attributable to pre-combination service (ii) 144 Fair value of replacement warrants (iii) 618 Provisional purchase price $ 10,732
Summary of Preliminary Acquisition Date Fair Value of Assets Acquired and Liabilities Assumed	The following table summarizes the preliminary acquisition date fair value of the assets acquired and liabilities assumed (in thousands): Amount Assets acquired: Cash and cash equivalents $ 6,660 Prepaid expenses and other current assets 519 Intangible assets, net 24,458 Total identifiable assets $ 31,637 Liabilities assumed: Accounts payable ( 4,548 ) Accrued liabilities ( 7,531 ) Deferred tax liability, net ( 2,164 ) Deferred revenue ( 6,662 ) Total identifiable liabilities ( 20,905 ) Net assets acquired $ 10,732
Schedule of Supplemental Pro Forma Information	On a pro forma basis to give effect to the Merger as if it occurred on January 1, 2022, net loss for the years ended December 31, 2023 and 2022, respectively, would have been as follows: Year Ended December 31, 2023 2022 Net loss $ ( 97,791 ) $ ( 153,207 )

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2023
Fair Value Disclosures [Abstract]
Summary of Financial Instruments Carried at Fair Value on Recurring Basis	The following tables present the financial instruments carried at fair value on a recurring basis as of December 31, 2023 and 2022, respectively, in accordance with the FASB ASC 820 hierarchy (in thousands): December 31, 2023 Level 1 Level 2 Level 3 Total Cash equivalents Money market funds $ 8,360 $ — $ — $ 8,360 Marketable debt securities U.S. Treasury securities 109,634 — — 109,634 Total $ 117,994 $ — $ — $ 117,994 December 31, 2022 Level 1 Level 2 Level 3 Total Cash Equivalents Money market funds $ 177,279 $ — $ — $ 177,279 Restricted Cash Money market funds 1,472 — — 1,472 Total $ 178,751 $ — $ — $ 178,751

Marketable Debt Securities (Tab

Marketable Debt Securities (Tables)	12 Months Ended
	Dec. 31, 2023
Investments, Debt and Equity Securities [Abstract]
Summary of Marketable Securities Classified as Available-for-sale	Marketable debt securities, all of which were classified as available-for-sale, consist of the following (in thousands): December 31, 2023 Amortized Unrealized Unrealized Aggregate Marketable debt securities U.S. Treasury securities $ 109,571 $ 71 $ ( 8 ) $ 109,634
Interest and Investment Income	Interest and investment income consisted of the following (in thousands): Year Ended December 31, 2023 2022 Interest income $ 1,842 $ 2,764 Accretion of discount, net 4,788 — Total interest and investment income $ 6,630 $ 2,764

Prepaid Expenses and Other Cu_2

Prepaid Expenses and Other Current Assets (Tables)	12 Months Ended
	Dec. 31, 2023
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Schedule of Prepaid Expenses and Other Current Assets	Prepaid expenses and other current assets consisted of the following (in thousands): December 31, 2023 2022 Research and development $ 2,496 $ 3,560 Insurance 1,012 1,308 Accrued interest receivable 21 598 Other 305 381 Total prepaid expenses and other current assets $ 3,834 $ 5,847

Property and Equipment, Net (Ta

Property and Equipment, Net (Tables)	12 Months Ended
	Dec. 31, 2023
Property, Plant and Equipment [Abstract]
Schedule of Property and Equipment, Net	Property and equipment, net, consisted of the following (in thousands): December 31, 2023 2022 Leasehold improvements $ 10,956 $ 530 Laboratory equipment 3,395 2,247 Furniture and office equipment 1,123 1,036 Construction in process — 9,177 15,474 12,990 Less: accumulated depreciation and amortization ( 3,602 ) ( 1,825 ) Total property and equipment, net $ 11,872 $ 11,165

Intangible Assets, Net (Tables)

Intangible Assets, Net (Tables)	12 Months Ended
	Dec. 31, 2023
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Intangible Assets, Net	Intangible assets, net, consisted of the following (in thousands): As of December 31, 2023 Estimated Useful Life Gross Carrying Accumulated Net Carrying Royalty rights 3 - 13 years $ 3,494 $ ( 150 ) $ 3,344 IPR&D Indefinite 20,964 — 20,964 Total $ 24,458 $ ( 150 ) $ 24,308
Schedule of Amortization of Intangible Assets	Amortization of intangible assets for the next five years related to the intangible assets held as of December 31, 2023 is estimated to be as follows (in thousands): Years Ending December 31, Estimated Amortization Expense 2024 $ 421 2025 421 2026 322 2027 223 2028 223 Thereafter 1,734 Total $ 3,344

Accrued Expenses and Other Cu_2

Accrued Expenses and Other Current Liabilities (Tables)	12 Months Ended
	Dec. 31, 2023
Payables and Accruals [Abstract]
Summary of Accrued Expenses and Other Current Liabilities	Accrued expenses and other current liabilities consisted of the following (in thousands): December 31, 2023 2022 Research and development expenses $ 6,594 $ 17,414 Employee compensation and benefits 5,219 4,238 Legal and professional fees 802 1,794 Other 356 1,091 Total accrued expenses and other current liabilities $ 12,971 $ 24,537

Operating Leases (Tables)

Operating Leases (Tables)	12 Months Ended
	Dec. 31, 2023
Leases [Abstract]
Components of Lease Expense	The components of lease expense were as follows (in thousands): Year Ended December 31, 2023 2022 Lease cost Operating lease cost $ 2,666 $ 1,978 Variable lease cost 753 121 Short-term lease cost 499 1,681 Total lease cost $ 3,918 $ 3,780 Other information Operating lease right-of-use asset obtained in exchange for new operating lease liabilities $ — $ 14,497 Cash paid for amounts included in the measurement of lease liabilities, included in operating cash flows $ 2,516 $ 663 Weighted-average remaining lease term (in years) 9.00 10.00 Weighted-average discount rate 9.40 % 9.40 %
Maturities of Lease Liabilities	Maturities of lease liabilities as of December 31, 2023, were as follows (in thousands): Years Ending December 31, Operating Lease Payments Sublease Receipts Net Operating Lease Payments 2024 $ 3,185 $ 1,844 $ 1,341 2025 3,278 1,898 1,380 2026 3,375 437 2,938 2027 3,473 — 3,473 2028 3,575 — 3,575 Thereafter 15,383 — 15,383 Total undiscounted payments $ 32,269 $ 4,179 $ 28,090 Less: present value adjustment ( 10,938 ) Present value of future payments 21,331 Less: current portion of operating lease liabilities ( 1,232 ) Operating lease liabilities, net of current portion $ 20,099

Common Stock Warrants (Tables)

Common Stock Warrants (Tables)	12 Months Ended
	Dec. 31, 2023
Share-Based Payment Arrangement [Abstract]
Summary of Fair Value of Replacement Warrants Black-Scholes Option Pricing Model	The fair value of the Replacement Warrants was determined using the Black-Scholes option-pricing model and the following assumptions: As of August 23, 2023 Expected volatility 95.0 % Risk-free interest rate 4.36 % - 4.50 % Expected dividend yield 0.00 % Expected term (in years) 3.93 - 4.94

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	12 Months Ended
	Dec. 31, 2023
Equity [Abstract]
Common Stock Reserved for Issuance	The Company reserved the following shares of common stock for issuance: December 31, 2023 2022 Stock options outstanding 5,982,464 5,720,415 Unvested restricted stock awards and units 3,631,431 3,015,387 Shares reserved for future issuance 1,013,840 1,697,166 Common stock warrants 1,003,191 — Employee stock purchase plan 565,405 534,675 Total 12,196,332 10,967,643

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2023
Share-Based Payment Arrangement [Abstract]
Summary of Stock Option Activity	The following table summarizes stock option activity for the year ended December 31, 2023 (in thousands, except share and per share amounts): Number of Options Weighted Average Weighted Average Aggregate Outstanding at January 1, 2023 5,720,415 $ 9.68 8.8 $ 72 Granted 1,078,717 1.87 Replacement Options (1) 712,181 17.57 Exercised ( 83,235 ) 1.49 Expired ( 721,598 ) 13.63 Forfeited ( 724,016 ) 8.23 Outstanding at December 31, 2023 5,982,464 $ 7.31 (1) 7.6 $ 141 (2) Options exercisable at December 31, 2023 3,300,648 $ 7.97 (1) 6.8 $ 44 (2) (1) Represents Replacement Options issued to Apexigen grantholders pursuant to the Merger Agreement. (2) The weighted average exercise price and aggregate intrinsic value as of December 31, 2023 reflect the impact of the stock option repricing discussed above.
Schedule of Estimated Fair Value Assumptions	The Company estimated the fair value of each option on the date of grant using the Black-Scholes option-pricing model applying the range of assumptions in the following table: Year Ended December 31, 2023 2022 Expected volatility 97.11 % - 118.90 % 96.09 % - 101.66 % Risk-free interest rate 3.58 % - 5.57 % 1.60 % - 4.02 % Expected dividend yield 0.00 % 0.00 % Expected term (in years) 0.25 - 6.08 6.00 - 6.11
Summary of Restricted Stock Awards and Restricted Stock Units	The following table summarizes restricted stock awards and restricted stock units for the year ended December 31, 2023: Number of Shares Weighted Average Non-vested and unsettled at January 1, 2023 3,015,387 $ 3.64 Granted 4,200,428 2.09 Replacement RSU Awards (1) 34,500 2.30 Forfeited ( 918,845 ) 3.12 Vested and settled ( 2,700,039 ) 2.91 Non-vested and unsettled at December 31, 2023 3,631,431 $ 2.51 (1) Represents Replacement RSU Awards issued to eligible Apexigen grantholders pursuant to the Merger Agreement.
Summary of Total Stock-based Compensation Expense	The following tables summarize the total stock-based compensation expense for the years ended December 31, 2023 and 2022, respectively (in thousands): Year Ended December 31, 2023 2022 Stock options $ 10,635 $ 11,947 Restricted stock 6,311 3,817 Total $ 16,946 $ 15,764 Year Ended December 31, 2023 2022 General and administrative $ 12,537 $ 10,548 Research and development 4,409 5,216 Total $ 16,946 $ 15,764

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2023
Income Tax Disclosure [Abstract]
Reconciliation of Federal Statutory Income Tax Rate to Effective Income Tax Rate	A reconciliation of the expected income tax benefit computed using the federal statutory income tax rate to the Company’s effective income tax rate is as follows for the years ended December 31, 2023 and 2022: Year Ended December 31, 2023 2022 Income tax computed at federal statutory rate % 21.0 % 21.0 % State taxes, net of federal benefit 2.1 % 5.6 % Share based compensation - 3.5 % - 1.7 % Change in valuation allowance - 19.3 % - 26.6 % Change in state apportionment 0.0 % - 0.1 % Provision to tax return differences - 3.0 % - 0.4 % Research and development credit carryovers 3.0 % 1.7 % Permanent differences - 0.3 % 0.5 % Effective income tax rate % 0.0 % 0.0 %
Components of Net Deferred Tax Assets	Significant components of the Company’s net deferred tax assets as of December 31, 2023 and 2022 are as follows (in thousands): Year Ended December 31, 2023 2022 Deferred tax assets: Net operating losses $ 67,569 $ 13,108 Tax credit carryforwards 10,689 3,674 Derivative 1,319 1,455 Stock-based compensation 3,204 2,645 Reserves and accruals 1,156 1,105 Capitalized research expenditures 23,423 20,059 License fees 13,555 14,235 Operating lease liability 3,996 5,107 Deferred revenue 2,027 — Intangibles — 69 Other 183 29 Total gross deferred tax assets before valuation allowance 127,121 61,486 Less: valuation allowance ( 119,504 ) ( 57,812 ) Total deferred tax assets $ 7,617 $ 3,674 Deferred tax liabilities: Operating lease ROU assets ( 3,459 ) ( 3,674 ) Intangibles ( 6,322 ) — Total deferred tax liabilities ( 9,781 ) ( 3,674 ) Net deferred tax liabilities $ ( 2,164 ) $ —
Reconciliation of Unrecognized Tax Benefits	A reconciliation of the beginning and ending amounts of unrecognized tax benefits is as follows (in thousands): Year Ended December 31, 2023 2022 Gross unrecognized tax benefit at January 1 $ — $ — Additions for positions taken during a prior period 2,003 — Gross unrecognized tax benefit at December 31 $ 2,003 $ —

Net Loss per Share (Tables)

Net Loss per Share (Tables)	12 Months Ended
	Dec. 31, 2023
Earnings Per Share [Abstract]
Summary of Basic and Diluted Net Loss Per Share	Basic and diluted net loss per share was calculated as follows (in thousands, except share and per share amounts): Year Ended December 31, 2023 2022 Numerator: Net loss $ ( 73,790 ) $ ( 120,717 ) Denominator: Weighted-average common shares outstanding, basic and diluted 39,904,603 33,033,081 Net loss per share, basic and diluted $ ( 1.85 ) $ ( 3.65 )
Anti-Dilutive Effect Excluded from Computation of Diluted Net Loss Per Share Attributable to Common Stockholders	The following potentially dilutive securities have been excluded from the calculation of diluted net loss per common share due to their anti-dilutive effect: December 31, 2023 2022 Stock options outstanding 5,982,464 5,720,415 Unvested restricted stock awards and units 3,631,431 3,015,387 Shares reserved for future issuance 1,013,840 1,697,166 Common stock warrants 1,003,191 — Employee stock purchase plan 565,405 534,675 Total 12,196,332 10,967,643

Description of Business - Addit

Description of Business - Additional Information (Details)	12 Months Ended
	Dec. 31, 2023 Segment
Segment Reporting [Abstract]
Operating and Reporting Segment	1

Basis of Presentation and Sum_4

Basis of Presentation and Summary of Significant Accounting Policies - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Accumulated deficit	$ (286,225,000)	$ (212,435,000)
Net loss	73,790,000	120,717,000
Cash, cash equivalents and short-term investments	119,300,000
Impairment losses	$ 0	$ 0
ASU 2016-13
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Change in accounting principle, accounting standards update, adopted [true false]	true
Change in accounting principle, accounting standards update, adoption date	Jan. 01, 2023
Change in accounting principle, accounting standards update, immaterial effect [true false]	true
ASU 2021-08
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Change in accounting principle, accounting standards update, adopted [true false]	true
Change in accounting principle, accounting standards update, adoption date	Jan. 01, 2023
Change in accounting principle, accounting standards update, immaterial effect [true false]	true

Basis of Presentation and Sum_5

Basis of Presentation and Summary of Significant Accounting Policies - Schedule of Estimated Useful Lives of Related Assets (Details)	Dec. 31, 2023
Laboratory Equipment
Property, Plant and Equipment [Line Items]
Estimated useful lives of related assets	3 years
Furniture and Office Equipment
Property, Plant and Equipment [Line Items]
Estimated useful lives of related assets	3 years
Leasehold Improvements
Property, Plant and Equipment [Line Items]
Property, Plant, and Equipment, Useful Life, Term, Description [Extensible Enumeration]	us-gaap:UsefulLifeShorterOfTermOfLeaseOrAssetUtilityMember

Acquisition of Apexigen - Addit

Acquisition of Apexigen - Additional Information (Details) - USD ($)		12 Months Ended
	Aug. 23, 2023	Dec. 31, 2023
Business Acquisition [Line Items]
Right to receive shares conversion	0.1725
Deferred tax liability, net	$ (2,164,000)
Apexigen, Inc.
Business Acquisition [Line Items]
Stock issued	4,344,435
Deferred tax liability, net	$ (2,200,000)
Issuance costs, incurred		$ 0
General and Administrative
Business Acquisition [Line Items]
Transaction related costs, incurred		$ 1,700,000

Acquisition of Apexigen - Summa

Acquisition of Apexigen - Summary of Acquisition Date Fair Value of Consideration Transferred (Details) - Apexigen, Inc. - USD ($) $ in Thousands		12 Months Ended
	Aug. 23, 2023	Dec. 31, 2023
Business Acquisition [Line Items]
Fair value of consideration transferred	$ 9,970
Provisional purchase price	10,732
Replacement Options and RSU
Business Acquisition [Line Items]
Fair value of consideration transferred	144
Replacement Warrants
Business Acquisition [Line Items]
Fair value of consideration transferred	$ 618	$ 600

Acquisition of Apexigen - Sum_2

Acquisition of Apexigen - Summary of Acquisition Date Fair Value of Consideration Transferred (Parenthetical) (Details) - USD ($) $ in Thousands		12 Months Ended
	Aug. 23, 2023	Dec. 31, 2023
Replacement Options
Business Acquisition [Line Items]
Number of Options, Replacement Options	712,181
Replacement RSUs
Business Acquisition [Line Items]
Number of Options, Replacement Options	34,500
Apexigen, Inc.
Business Acquisition [Line Items]
Acquisition date fair value of replacement awards	$ 9,970
Apexigen, Inc. | Replacement Options
Business Acquisition [Line Items]
Number of Options, Replacement Options	4,128,809
Apexigen, Inc. | Replacement Options | Black-Scholes Option-Pricing Model
Business Acquisition [Line Items]
Acquisition date fair value of replacement awards	$ 100
Apexigen, Inc. | Replacement RSUs
Business Acquisition [Line Items]
Number of Options, Replacement Options	200,000
Apexigen, Inc. | Replacement Warrants
Business Acquisition [Line Items]
Number of Options, Replacement Options	5,815,613
Acquisition date fair value of replacement awards	$ 618	$ 600
Apexigen, Inc. | Replacement Warrants | Black-Scholes Option-Pricing Model
Business Acquisition [Line Items]
Acquisition date fair value of replacement awards	$ 600
Pyxis Oncology | Replacement Options
Business Acquisition [Line Items]
Number of Options, Replacement Options	712,181
Pyxis Oncology | Replacement RSUs
Business Acquisition [Line Items]
Number of Options, Replacement Options	34,500
Pyxis Oncology | Replacement Warrants
Business Acquisition [Line Items]
Number of Options, Replacement Options	1,003,191

Acquisition of Apexigen - Sum_3

Acquisition of Apexigen - Summary of Preliminary Acquisition Date Fair Value of Assets Acquired and Liabilities Assumed (Details) $ in Thousands	Aug. 23, 2023 USD ($)
Assets acquired:
Cash and cash equivalents	$ 6,660
Prepaid expenses and other current assets	519
Intangible assets, net	24,458
Total identifiable assets	31,637
Liabilities assumed:
Accounts payable	(4,548)
Accrued liabilities	(7,531)
Deferred tax liability, net	(2,164)
Deferred revenue	(6,662)
Total identifiable liabilities	(20,905)
Net assets acquired	10,732
Apexigen, Inc.
Liabilities assumed:
Deferred tax liability, net	$ (2,200)

Acquisition of Apexigen - Sched

Acquisition of Apexigen - Schedule of Supplemental Pro Forma Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Apexigen, Inc.
Business Acquisition [Line Items]
Net loss	$ (97,791)	$ (153,207)

License Agreements - Additional

License Agreements - Additional Information (Details) - USD ($)

1 Months Ended

12 Months Ended

Mar. 28, 2022

Jan. 31, 2022

Jan. 31, 2023

Oct. 31, 2021

Mar. 31, 2021

Dec. 31, 2020

Apr. 30, 2020

Dec. 31, 2023

Dec. 31, 2022

Dec. 31, 2020

Mar. 31, 2023

Oct. 06, 2022

Research And Development Arrangement Contract To Perform For Others [Line Items]

Research and development expense

$ 49,586,000

$ 86,129,000

Deferred revenue

$ 7,660,000

Common stock, shares issued

44,754,853

35,110,016

Common Stock, Value, Issued

$ 45,000

$ 34,000

Apexigen, Inc.

Research And Development Arrangement Contract To Perform For Others [Line Items]

Deferred revenue

7,700,000

Milestone and royalties payments received post acquisition

1,000,000

Esbatech Agreement

Research And Development Arrangement Contract To Perform For Others [Line Items]

Deferred revenue

7,700,000

Pfizer License Agreement

Research And Development Arrangement Contract To Perform For Others [Line Items]

Payment for license fee

$ 25,000,000

Common stock, shares issued

1,811,594

2,229,654

Royalty obligation period for licensed products upon first commercial sale

12 years

Milestone and royalties required

0

0

Upfront payments

$ 8,000,000

5,000,000

Pfizer License Agreement | Maximum

Research And Development Arrangement Contract To Perform For Others [Line Items]

Aggregate milestone payments for first four licensed products

$ 665,000,000

Pfizer License Agreement | IPO

Research And Development Arrangement Contract To Perform For Others [Line Items]

Number of common shares issued upon conversion of preferred stock

1,911,015

Pfizer License Agreement | Series B Convertible Preferred Stock

Research And Development Arrangement Contract To Perform For Others [Line Items]

Issuance of convertible preferred stock shares

12,152,145

Issuance of convertible preferred stock value

$ 20,000,000

LegoChem License Agreement

Research And Development Arrangement Contract To Perform For Others [Line Items]

Estimated cost to purchase licensed products

7,000,000

Milestone and royalties required

0

Stock option upfront payments

$ 8,000,000

Extra milestone payment

$ 9,600,000

Extra milestone payment for which derivative liability recognized

$ 9,600,000

LegoChem License Agreement | Research and Development Expenses

Research And Development Arrangement Contract To Perform For Others [Line Items]

Upfront fee

$ 9,000,000

Biosion License Agreement

Research And Development Arrangement Contract To Perform For Others [Line Items]

Aggregate maximum obligation to pay future contingent milestone payments for normal approval

$ 217,500,000

Aggregate maximum obligation to pay future contingent milestone payments for accelerated approval

$ 222,500,000

Royalty obligation period for licensed products upon first commercial sale

12 years

Milestone and royalties required

0

0

Biosion License Agreement | Research and Development Expenses

Research And Development Arrangement Contract To Perform For Others [Line Items]

Upfront fee

$ 10,000,000

Simcere License Agreement

Research And Development Arrangement Contract To Perform For Others [Line Items]

Royalty obligation period for licensed products upon after first commercial sale

15 years

Milestone and royalties receivable

0

Mabwell Agreement

Research And Development Arrangement Contract To Perform For Others [Line Items]

Milestone and royalties receivable

$ 0

Toray Sublicense Agreement

Research And Development Arrangement Contract To Perform For Others [Line Items]

Royalty obligation period for licensed products upon after first commercial sale

10 years

Milestone and royalties receivable

$ 0

University License Agreement

Research And Development Arrangement Contract To Perform For Others [Line Items]

Common stock issued to university

48,919

Milestone and royalties required

$ 0

$ 0

University License Agreement | Maximum

Research And Development Arrangement Contract To Perform For Others [Line Items]

Potential development and commercial milestones

$ 7,700,000

Minimum annual royalty fees

$ 3,000,000

Joint Venture - Additional Info

Joint Venture - Additional Information (Details) - Voxall $ in Thousands	1 Months Ended
	Mar. 31, 2021 USD ($)
Schedule Of Equity Method Investments [Line Items]
Contribution to joint venture	$ 50
Alloy Therapeutics, Inc.
Schedule Of Equity Method Investments [Line Items]
Percentage of voting membership units	50%

Fair Value Measurements - Summa

Fair Value Measurements - Summary of Financial Instruments Carried at Fair Value on Recurring Basis (Details) - USD ($)	Dec. 31, 2023	Dec. 31, 2022
Fair Value Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable debt securities		$ 0
U S Treasury Securities
Fair Value Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable debt securities	$ 109,634,000
Fair Value, Recurring
Fair Value Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total	117,994,000	178,751,000
Fair Value, Recurring | Money market funds
Fair Value Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	8,360,000	177,279,000
Restricted Cash		1,472,000
Fair Value, Recurring | U S Treasury Securities
Fair Value Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable debt securities	109,634,000
Fair Value, Recurring | Level 1
Fair Value Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total	117,994,000	178,751,000
Fair Value, Recurring | Level 1 | Money market funds
Fair Value Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	8,360,000	177,279,000
Restricted Cash		$ 1,472,000
Fair Value, Recurring | Level 1 | U S Treasury Securities
Fair Value Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable debt securities	$ 109,634,000

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Details) - Fair Value, Nonrecurring - USD ($)	Dec. 31, 2023	Dec. 31, 2022
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Assets measured at fair value	$ 0	$ 0
Liabilities measured at fair value	$ 0	$ 0

Marketable Debt Securities - Su

Marketable Debt Securities - Summary of Marketable Securities Classified as Available-for-sale (Details) - USD ($)	Dec. 31, 2023	Dec. 31, 2022
Debt Securities, Available-for-Sale [Line Items]
Marketable debt securities, Aggregate Fair Value		$ 0
U S Treasury Securities
Debt Securities, Available-for-Sale [Line Items]
Marketable debt securities, Amortized Cost	$ 109,571,000
Marketable debt securities, Unrealized Gains	71,000
Marketable debt securities, Unrealized Losses	(8,000)
Marketable debt securities, Aggregate Fair Value	$ 109,634,000

Marketable Debt Securities - Ad

Marketable Debt Securities - Additional Information (Details) - USD ($)	Dec. 31, 2023	Dec. 31, 2022
Debt Securities, Available-for-Sale [Line Items]
Marketable debt securities at fair value		$ 0
Securities in continuous unrealized loss position for less than twelve months	$ 8,000
Securities in unrealized loss position with fair value	41,700,000
Securities in continuous unrealized loss position for greater than twelve months	0
U S Treasury Securities
Debt Securities, Available-for-Sale [Line Items]
Marketable debt securities at fair value	$ 109,634,000

Marketable Debt Securities - In

Marketable Debt Securities - Interest and Investment Income (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Investments, Debt and Equity Securities [Abstract]
Interest income	$ 1,842	$ 2,764
Accretion of discount, net	4,788
Total interest and investment income	$ 6,630	$ 2,764

Prepaid Expenses and Other Cu_3

Prepaid Expenses and Other Current Assets - Schedule of Prepaid Expenses and Other Current Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Prepaid Expense and Other Assets, Current [Abstract]
Research and development	$ 2,496	$ 3,560
Insurance	1,012	1,308
Accrued interest receivable	21	598
Other	305	381
Total Prepaid expenses and other current assets	$ 3,834	$ 5,847

Property and Equipment, Net - S

Property and Equipment, Net - Schedule of Property and Equipment, Net (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Property, Plant and Equipment [Line Items]
Property and equipment gross	$ 15,474	$ 12,990
Less: accumulated depreciation and amortization	(3,602)	(1,825)
Total Property and equipment, net	11,872	11,165
Leasehold Improvements
Property, Plant and Equipment [Line Items]
Property and equipment gross	10,956	530
Laboratory Equipment
Property, Plant and Equipment [Line Items]
Property and equipment gross	3,395	2,247
Furniture and Office Equipment
Property, Plant and Equipment [Line Items]
Property and equipment gross	$ 1,123	1,036
Construction in process
Property, Plant and Equipment [Line Items]
Property and equipment gross		$ 9,177

Property and Equipment, Net - A

Property and Equipment, Net - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Property, Plant and Equipment [Line Items]
Depreciation and amortization expense	$ 1,800	$ 700
General and Administrative
Property, Plant and Equipment [Line Items]
Depreciation and amortization expense	300	15
Research and Development Expenses
Property, Plant and Equipment [Line Items]
Depreciation and amortization expense	$ 1,500	$ 700

Intangible Assets, Net - Schedu

Intangible Assets, Net - Schedule of Intangible Assets, Net (Details) $ in Thousands	Dec. 31, 2023 USD ($)
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 24,458
Accumulated Amortization	(150)
Net Carrying Amount	24,308
IPR&D
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	20,964
Net Carrying Amount	20,964
Royalty Rights
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	3,494
Accumulated Amortization	(150)
Net Carrying Amount	$ 3,344
Royalty Rights | Minimum
Finite-Lived Intangible Assets [Line Items]
Estimated Useful Life	3 years
Royalty Rights | Maximum
Finite-Lived Intangible Assets [Line Items]
Estimated Useful Life	13 years

Intangible Assets, Net - Additi

Intangible Assets, Net - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Finite-Lived Intangible Assets [Line Items]
Intangible assets		$ 0
Royalty Rights
Finite-Lived Intangible Assets [Line Items]
Acquired weighted-average amortization	8 years 3 months 18 days
Minimum | Royalty Rights
Finite-Lived Intangible Assets [Line Items]
Estimated Useful Life	3 years
Maximum | Royalty Rights
Finite-Lived Intangible Assets [Line Items]
Estimated Useful Life	13 years
Research and Development
Finite-Lived Intangible Assets [Line Items]
Amortization expense	$ 200,000

Intangible Assets, Net - Sche_2

Intangible Assets, Net - Schedule of Amortization of Intangible Assets (Details) $ in Thousands	Dec. 31, 2023 USD ($)
Estimated Amortization Expense
2024	$ 421
2025	421
2026	322
2027	223
2028	223
Thereafter	1,734
Net Carrying Amount	$ 3,344

Accrued Expenses and Other Cu_3

Accrued Expenses and Other Current Liabilities - Summary of Accrued Expenses (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Payables and Accruals [Abstract]
Research and development expenses	$ 6,594	$ 17,414
Employee compensation and benefits	5,219	4,238
Legal and professional fees	802	1,794
Other	356	1,091
Total Accrued expenses and other current liabilities	$ 12,971	$ 24,537

Operating Leases - Additional I

Operating Leases - Additional Information (Details) $ in Thousands		12 Months Ended
	Feb. 02, 2023 USD ($) ft²	Dec. 31, 2023 USD ($)
Leases [Abstract]
Sublease agreement, square feet space area in building | ft²	17,729
Sublease payment in year one	$ 1,500	$ 3,185
Sublease payment per year thereafter	$ 1,900
Sublessee annual rent increase percentage	3%
Lessee, operating sublease, option to extend		The sublessee has the option to extend the sublease for a one-year period on the same terms and conditions as the current sublease, subject to a change in base rent for the extended period equal to a 3% increase to the then current rent.
Lessee, Operating Sublease, Existence of Option to Extend [true false]		true
Percentage of increase in current rent	3%
Security deposit		$ 400
Sublease income		$ 1,776

Operating Leases - Components o

Operating Leases - Components of Lease Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Leases [Abstract]
Operating lease cost	$ 2,666	$ 1,978
Variable lease cost	753	121
Short-term lease cost	499	1,681
Total lease cost	3,918	3,780
Operating lease right-of-use asset obtained in exchange for new operating lease liabilities		14,497
Cash paid for amounts included in the measurement of lease liabilities, included in operating cash flows	$ 2,516	$ 663
Weighted-average remaining lease term	9 years	10 years
Weighted-average discount rate	9.40%	9.40%

Operating Leases - Maturities o

Operating Leases - Maturities of Lease Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Feb. 02, 2023	Dec. 31, 2022
Operating Lease Payments
2023	$ 3,185	$ 1,500
2024	3,278
2025	3,375
2026	3,473
2027	3,575
Thereafter	15,383
Total undiscounted payments	32,269
Less: present value adjustment	(10,938)
Present value of future payments	21,331
Less: current portion of operating lease liabilities	(1,232)
Operating lease liabilities, net of current portion	20,099		$ 18,921
Sublease Receipts
2024	1,844
2025	1,898
2026	437
Sublease Receipts, Total	4,179
Net Operating Lease Payments
2024	1,341
2025	1,380
2026	2,938
2027	3,473
2028	3,575
Thereafter	15,383
Net Operating Lease Payments, Total	$ 28,090

Common Stock Warrants - Summary

Common Stock Warrants - Summary of Fair Value of Replacement Warrants Black-Scholes Option Pricing Model (Details)		12 Months Ended
	Aug. 23, 2023	Dec. 31, 2023	Dec. 31, 2022
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Risk-free interest rate, maximum		5.57%	4.02%
Risk-free interest rate, minimum		3.58%	1.60%
Expected dividend yield		0%	0%
Minimum
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Expected term (in years)		3 months	6 years
Maximum
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Expected term (in years)		6 years 29 days	6 years 1 month 9 days
Replacement Warrants
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Expected volatility	95%
Risk-free interest rate, maximum	4.50%
Risk-free interest rate, minimum	4.36%
Expected dividend yield	0%
Replacement Warrants | Minimum
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Expected term (in years)	3 years 11 months 4 days
Replacement Warrants | Maximum
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Expected term (in years)	4 years 11 months 8 days

Common Stock Warrants - Additio

Common Stock Warrants - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands		12 Months Ended
	Aug. 23, 2023	Dec. 31, 2023	Jul. 29, 2022
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Replacement of warrants		1,003,191
Warrants redemption exercise price per share		$ 0.01
Sale price per share		$ 104.35
Consecutive trading days		20 days
Apexigen, Inc.
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Acquisition date fair value of replacement awards	$ 9,970
Replacement of warrants		5,815,613
Apexigen, Inc. | Replacement Warrants
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Acquisition date fair value of replacement awards	$ 618	$ 600
Minimum [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Redemption notice period		30 days
Maximum [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Trading days		30 days
Warrant One
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Warrants outstanding		344,259
Warrants exercise price per share		$ 8.12
Warrant Two
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Warrants outstanding		17,212
Warrants exercise price per share		$ 10.14
Warrant Three
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Warrants outstanding		641,720
Warrants exercise price per share		$ 66.67	$ 66.67

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Nov. 14, 2022	Nov. 01, 2022
Schedule of Equity Method Investments [Line Items]
Preferred stock, par or stated value per share	$ 0.001	$ 0.001
Preferred stock, shares authorized	10,000,000	10,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, shares authorized	190,000,000	190,000,000
Common stock, shares issued	44,754,853	35,110,016
Common stock, shares outstanding	44,754,853	34,958,730
Common stock voting rights	one
Maximum value of stock and debt instruments authorized to issue				$ 250,000
Common stock issued, value	$ 45	$ 34
ATM Offering Program
Schedule of Equity Method Investments [Line Items]
Sales agents commission rate	3%
ATM Offering Program | Maximum
Schedule of Equity Method Investments [Line Items]
Common stock issued, value			$ 125,000
Common Stock
Schedule of Equity Method Investments [Line Items]
Stock issued		2,229,654
Common stock issued under ATM offering program	1,001,208
Common Stock | ATM Offering Program
Schedule of Equity Method Investments [Line Items]
Average gross sale price per share	$ 6.3
Gross proceeds from sale of shares	$ 6,300
Commissions paid to the placement agent	$ 200

Stockholders' Equity - Common S

Stockholders' Equity - Common Stock Reserved for Issuance (Details) - shares	Dec. 31, 2023	Dec. 31, 2022
Schedule Of Common Stock Reserved For Future Issuance [Line Items]
Common stock reserved for future issuance	12,196,332	10,967,643
Stock Options Outstanding
Schedule Of Common Stock Reserved For Future Issuance [Line Items]
Common stock reserved for future issuance	5,982,464	5,720,415
Unvested Restricted Stock Awards and Units
Schedule Of Common Stock Reserved For Future Issuance [Line Items]
Common stock reserved for future issuance	3,631,431	3,015,387
Shares Reserved for Future Issuance
Schedule Of Common Stock Reserved For Future Issuance [Line Items]
Common stock reserved for future issuance	1,013,840	1,697,166
Common Stock Warrants
Schedule Of Common Stock Reserved For Future Issuance [Line Items]
Common stock reserved for future issuance	1,003,191
Employee Stock Purchase Plan
Schedule Of Common Stock Reserved For Future Issuance [Line Items]
Common stock reserved for future issuance	565,405	534,675

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands				12 Months Ended
	Aug. 23, 2023	Mar. 24, 2023	Jan. 01, 2023	Dec. 31, 2023	Dec. 31, 2022	Dec. 29, 2023	Jul. 01, 2022	Sep. 27, 2021	Dec. 31, 2019
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of common shares reserved and autorized for future issuance				12,196,332	10,967,643
Number of options to purchase common stock				5,982,464	5,720,415
Number of option to purchase restricted common stock				3,631,431	3,015,387
Incremental stock-based compensation expense				$ 1,100
Incremental stock-based compensation expense recognized				$ 900
Fair value of common stock per share						$ 1.8
Weighted-average fair value of options granted				$ 1.87	$ 3.06
Intrinsic value of options exercised				$ 100	$ 100
Gross unrecognized stock-based compensation expense				$ 9,100
Unrecognized stock-based compensation expense weighted average amortized period				1 year 11 months 12 days
Number of restricted stock units granted				4,200,428
Stock-based compensation expense				$ 16,946	$ 15,764
Apexigen
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Purchase price	$ 10,732
Restricted Stock Awards
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of common shares reserved and autorized for future issuance				3,631,431	3,015,387
Stock-based compensation expense				$ 6,311	$ 3,817
Restricted Stock Units ('RSU')
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of option to purchase restricted common stock				2,700,039
Fair value of restricted common stock vested				$ 8,000	500
Unrecognized stock-based compensation expense weighted average amortized period				2 years 5 months 23 days
Number of restricted stock units granted				4,200,428
Common stock public offering price per share				$ 0.01
Gross unrecognized stock-based compensation expense				$ 6,800
Number of shares issued				2,476,301
Replacement Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares issued	712,181
Replacement Options | Apexigen
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares issued	4,128,809
Purchase price	$ 100
Replacement RSUs
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares issued	34,500
Replacement RSUs | Apexigen
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares issued	200,000
2022 Equity Inducement Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of common shares reserved and autorized for future issuance							1,400,000
Number of options to purchase common stock				828,432
Number of common shares reserved for future issuance				346,443
2022 Equity Inducement Plan | Restricted Stock Awards
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of option to purchase restricted common stock				138,871
2022 Equity Inducement Plan | Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Award expiration period				10 years
2021 Equity Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of common shares reserved and autorized for future issuance								3,852,807
Number of additional shares authorized			1,755,501
Number of options to purchase common stock				2,037,393
Number of common shares reserved for future issuance				537,772
Number of shares of common stock outstanding percentage				5%
Maximum number of common shares issuable under exercise of options				7,705,614
2021 Equity Incentive Plan | Restricted Stock Awards
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of option to purchase restricted common stock				2,452,500
2021 Equity Incentive Plan | Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Award expiration period				10 years
2019 Equity Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Reduction in exercise price of relevant option		$ 2.21
Number of options to purchase common stock				2,272,833
Number of common shares reserved for future issuance				52,299
2019 Equity Incentive Plan | Restricted Stock Awards
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of option to purchase restricted common stock				962,390
2019 Equity Incentive Plan | Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Award expiration period				10 years
Number of common shares reserved and autorized for future issuance									4,042,408
2022 Equity Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of common shares reserved and autorized for future issuance				443,912
Number of additional shares authorized			554,890	554,890
Number of options to purchase common stock				843,806
Number of common shares reserved for future issuance				77,326
Number of shares of common stock outstanding percentage				0.8625%
Maximum number of common shares issuable under exercise of options				597,077
2022 Equity Incentive Plan | Restricted Stock Awards
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of option to purchase restricted common stock				77,670
2021 Employee Stock Purchase Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of common shares reserved and autorized for future issuance				565,405				424,595
Number of additional shares authorized			110,080	110,080
Number of shares of common stock outstanding percentage				1%
Stock-based compensation expense					$ 0
Number of shares issued				79,350
2021 Employee Stock Purchase Plan | Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense				$ 100
Stock Options 2022 Inducement Plan, 2022 Plan, 2020 Plan, 2021 Plan and 2019 Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Award expiration period				10 years
Stock options vesting period				4 years

Stock-Based Compensation - Summ

Stock-Based Compensation - Summary of Stock Option Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Share-Based Payment Arrangement [Abstract]
Number of Options, Outstanding, Beginning Balance	5,720,415
Number of Options, Granted	1,078,717
Number of Options, Replacement Options	712,181
Number of Options, Exercised	(83,235)
Number of Options, Expired	(721,598)
Number of Options, Forfeited	(724,016)
Number of Options, Outstanding, Ending Balance	5,982,464	5,720,415
Number of Options, Exercisable at December 31, 2023	3,300,648
Weighted Average Exercise Price, Beginning Balance	$ 9.68
Weighted Average Exercise Price, Granted	1.87
Weighted Average Exercise Price, Replacement Options	17.57
Weighted Average Exercise Price, Exercised	1.49
Weighted Average Exercise Price, Expired	13.63
Weighted Average Exercise Price, Forfeited	8.23
Weighted Average Exercise Price, Ending Balance	7.31	$ 9.68
Weighted Average Exercise Price, Exercisable at December 31, 2023	$ 7.97
Weighted Average Remaining Contractual Term, Outstanding	7 years 7 months 6 days	8 years 9 months 18 days
Weighted Average Remaining Contractual Term, Exercisable	6 years 9 months 18 days
Aggregate Intrinsic Value, Outstanding	$ 141	$ 72
Aggregate Intrinsic Value, Exercisable at December 31, 2023	$ 44

Stock-Based Compensation - Sche

Stock-Based Compensation - Schedule of Estimated Fair Value Assumptions (Details)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected volatility, minimum	97.11%	96.09%
Expected volatility, maximum	118.90%	101.66%
Risk-free interest rate, minimum	3.58%	1.60%
Risk-free interest rate, maximum	5.57%	4.02%
Expected dividend yield	0%	0%
Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected term (in years)	3 months	6 years
Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected term (in years)	6 years 29 days	6 years 1 month 9 days

Stock-Based Compensation - Su_2

Stock-Based Compensation - Summary of Restricted Stock Awards and Restricted Stock Units (Details)	12 Months Ended
	Dec. 31, 2023 $ / shares shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of Shares, Outstanding, Beginning Balance | shares	3,015,387
Number of Shares, Granted | shares	4,200,428
Number of Shares, Replacement RSU Awards | shares	34,500
Number of Shares, Forfeited | shares	(918,845)
Number of Shares, Vested and settled | shares	(2,700,039)
Number of Shares, Outstanding, Ending Balance | shares	3,631,431
Weighted Average Grant Date Fair Value, Outstanding, Beginning Balance | $ / shares	$ 3.64
Weighted Average Grant Date Fair Value, Outstanding, Granted | $ / shares	2.09
Weighted Average Grant Date Fair Value, Outstanding, Replacement RSU Awards | $ / shares	2.3
Weighted Average Grant Date Fair Value, Outstanding, Forfeited | $ / shares	3.12
Weighted Average Grant Date Fair Value, Outstanding, Vested and settled | $ / shares	2.91
Weighted Average Grant Date Fair Value, Outstanding, Ending Balance | $ / shares	$ 2.51

Stock-Based Compensation - Su_3

Stock-Based Compensation - Summary of Total Stock-based Compensation Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 16,946	$ 15,764
Stock Options
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	10,635	11,947
Restricted Stock
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	6,311	3,817
General and Administrative
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	12,537	10,548
Research and Development
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 4,409	$ 5,216

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Income Tax Contingency [Line Items]
Effective tax rate	0%	0%
Increase in deferred tax assets valuation allowance	$ 61,700,000	$ 32,100,000
Valuation allowance	119,504,000	57,812,000
Interest on reserves for unrecognized tax benefits	0
Penalties on reserves for unrecognized tax benefits	0
Federal
Income Tax Contingency [Line Items]
Current income tax expenses (benefit)	0	0
Deferred Income Tax Expense (Benefit)	0	0
Operating loss carryforward	56,400,000
Operating loss carryforwards before tax	268,500,000
Operating loss carryforwards relating to prior tax years	5,900,000
Operating loss carryforwards relating to prior tax years before tax	$ 28,300,000
Operating loss carryforwards expiration year	2033
Credit carryovers	$ 7,800,000
Credit carryovers expiration year	2030
State
Income Tax Contingency [Line Items]
Operating loss carryforward	$ 11,200,000
Operating loss carryforwards before tax	$ 167,400,000
Operating loss carryforwards expiration year	2035
Credit carryovers	$ 3,600,000
Credit carryovers expiration year	2030
State | Maximum
Income Tax Contingency [Line Items]
Current income tax expenses (benefit)	$ 100,000	$ 100,000

Income Taxes - Reconciliation o

Income Taxes - Reconciliation of Federal Statutory Income Tax Rate to Effective Income Tax Rate (Details)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Income Tax Disclosure [Abstract]
Income tax computed at federal statutory rate%	21%	21%
State taxes, net of federal benefit	2.10%	5.60%
Share based compensation	(3.50%)	(1.70%)
Change in valuation allowance	(19.30%)	(26.60%)
Change in state apportionment	(0.00%)	(0.10%)
Provision to tax return differences	(3.00%)	(0.40%)
Research and development credit carryovers	3%	1.70%
Permanent differences	(0.30%)	0.50%
Effective income tax rate%	0%	0%

Income Taxes - Components of Ne

Income Taxes - Components of Net Deferred Tax Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Deferred tax assets:
Net operating losses	$ 67,569	$ 13,108
Tax credit carryforwards	10,689	3,674
Derivative	1,319	1,455
Stock based compensation	3,204	2,645
Reserves and accruals	1,156	1,105
Capitalized research expenditures	23,423	20,059
License fees	13,555	14,235
Operating lease liability	3,996	5,107
Deferred revenue	2,027
Intangibles		69
Other	183	29
Total gross deferred tax assets before valuation allowance	127,121	61,486
Less: valuation allowance	(119,504)	(57,812)
Total deferred tax assets	7,617	3,674
Deferred tax liabilities:
Operating lease ROU assets	(3,459)	(3,674)
Intangibles	(6,322)
Total deferred tax liabilities	(9,781)	$ (3,674)
Net deferred tax liabilities	$ (2,164)

Income Taxes - Reconciliation_2

Income Taxes - Reconciliation of Unrecognized Tax Benefits (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2023 USD ($)
Income Tax Disclosure [Abstract]
Gross unrecognized tax benefit at January 1	$ 0
Additions for positions taken during a prior period	2,003
Gross unrecognized tax benefit at December 31	$ 2,003

Net Loss per Share - Summary of

Net Loss per Share - Summary of Basic and Diluted Net Loss Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Numerator:
Net loss	$ (73,790)	$ (120,717)
Denominator:
Weighted average shares of common stock outstanding - basic	39,904,603	33,033,081
Weighted average shares of common stock outstanding - diluted	39,904,603	33,033,081
Net loss per common share - basic	$ (1.85)	$ (3.65)
Net loss per common share - diluted	$ (1.85)	$ (3.65)

Net Loss per Share - Anti-Dilut

Net Loss per Share - Anti-Dilutive Effect Excluded from Computation of Diluted Net Loss Per Share Attributable to Common Stockholders (Details) - shares	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive effect excluded from computation of diluted net loss per share attributable to common stockholders	12,196,332	10,967,643
Stock Options Outstanding
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive effect excluded from computation of diluted net loss per share attributable to common stockholders	5,982,464	5,720,415
Unvested Restricted Stock Awards and Units
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive effect excluded from computation of diluted net loss per share attributable to common stockholders	3,631,431	3,015,387
Shares Reserved for Future Issuance
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive effect excluded from computation of diluted net loss per share attributable to common stockholders	1,013,840	1,697,166
Common Stock Warrants
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive effect excluded from computation of diluted net loss per share attributable to common stockholders	1,003,191
Employee Stock Purchase Plan
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive effect excluded from computation of diluted net loss per share attributable to common stockholders	565,405	534,675

Related Parties - Additional In

Related Parties - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Related Party Transaction [Line Items]
Research and development expense	$ 49,586,000	$ 86,129,000
Pfizer License Agreement
Related Party Transaction [Line Items]
Ownership percentage	10%
Voxall
Related Party Transaction [Line Items]
Contributed amount to joint venture			$ 50,000
Related Party | Pfizer License Agreement
Related Party Transaction [Line Items]
Related party transaction expenses incurred	$ 0	17,300,000
Related Party | Voxall
Related Party Transaction [Line Items]
Related party transaction expenses incurred	0	0
University License Agreement | Related Party
Related Party Transaction [Line Items]
Related party transaction expenses incurred	$ 200,000	$ 300,000

Subsequent Event - Additional I

Subsequent Event - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands			12 Months Ended
	Feb. 29, 2024	Jan. 30, 2024	Dec. 31, 2023	Feb. 26, 2024	Dec. 31, 2022	Dec. 31, 2021
Subsequent Event [Line Items]
Common stock, shares issued			44,754,853		35,110,016
Common stock, par value per share			$ 0.001		$ 0.001
Voxall
Subsequent Event [Line Items]
Initial investment in joint venture						$ 50
Common Stock
Subsequent Event [Line Items]
Common stock issued under ATM offering program			1,001,208
Common Stock | ATM Offering Program
Subsequent Event [Line Items]
Average sale price per share			$ 6.3
Gross proceeds from sale of shares			$ 6,300
Commissions paid to the placement agent			$ 200
Subsequent Event | Private Placement [Member]
Subsequent Event [Line Items]
Gross proceeds from private placement	$ 50,000
Subsequent Event | Pre-Funded Warrants
Subsequent Event [Line Items]
Purchase price per share				$ 4.779
Subsequent Event | Pre-Funded Warrants | Maximum
Subsequent Event [Line Items]
Warrants exercise price per share				$ 0.001
Subsequent Event | Common Stock
Subsequent Event [Line Items]
Common stock issued under ATM offering program		3,600,000
Subsequent Event | Common Stock | ATM Offering Program
Subsequent Event [Line Items]
Average sale price per share		$ 3
Gross proceeds from sale of shares		$ 10,800
Subsequent Event | Common Stock | Private Placement [Member]
Subsequent Event [Line Items]
Common stock, shares issued				8,849,371
Common stock, par value per share				$ 0.001
Purchase price per share				$ 4.78
Subsequent Event | Common Stock | Pre-Funded Warrants
Subsequent Event [Line Items]
Common stock, shares issued				1,611,215