Aptevo Therapeutics (APVO) 10-K5 Mar 242023 FY Annual reportFinancial data

Company Profile

Document and Entity Information

Document and Entity Information - USD ($) $ in Millions	12 Months Ended
Document and Entity Information - USD ($) $ in Millions	Dec. 31, 2023	Mar. 05, 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
Trading Symbol	APVO
Entity Registrant Name	APTEVO THERAPEUTICS INC.
Entity Central Index Key	0001671584
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Well-known Seasoned Issuer	No
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Interactive Data Current	Yes
Entity Shell Company	false
Entity Small Business	true
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	false
Document Financial Statement Error Correction [Flag]	false
Entity Common Stock, Shares Outstanding		23,472,436
Entity Public Float			$ 11
Title of 12(b) Security	Common Stock, $0.001 par value per share
Security Exchange Name	NASDAQ
Entity File Number	001-37746
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	81-1567056
Entity Address, Address Line One	2401 4th Avenue
Entity Address, Address Line Two	Suite 1050
Entity Address, City or Town	Seattle
Entity Address, State or Province	WA
Entity Address, Postal Zip Code	98121
City Area Code	206
Local Phone Number	838-0500
Document Annual Report	true
Document Transition Report	false
Documents Incorporated by Reference	Portions of the Registrant’s definitive proxy statement to be filed with the Securities and Exchange Commission pursuant to Regulation 14A, not later than 120 days after the end of the fiscal year covered by this Annual Report on Form 10-K, relating to the Registrant’s 2024 Annual Meeting of Stockholders are incorporated by reference into Part III of this Report.
Auditor Name	Moss Adams LLP
Auditor Firm ID	659
Auditor Location	Seattle, WA

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Current assets:
Cash and cash equivalents	$ 16,904	$ 22,635
Royalty and milestone receivable		2,500
Prepaid expenses	1,473	1,571
Other current assets	689	744
Total current assets	19,066	27,450
Property and equipment, net	895	1,462
Operating lease right-of-use asset	4,881	5,303
Total assets	24,842	34,215
Current liabilities:
Accounts payable and other accrued liabilities	3,984	3,499
Accrued compensation	2,098	2,105
Current portion of long-term debt		2,000
Other current liabilities	1,142	1,102
Total current liabilities	7,224	8,706
Long-term debt		1,456
Operating lease liability	5,397	6,079
Total liabilities	12,621	16,241
Stockholders' equity:
Common stock: $0.001 par value; 500,000,000 shares authorized; 19,468,180 and 6,466,294 shares issued and outstanding at December 31, 2023 and December 31, 2022, respectively	61	48
Additional paid-in capital	235,607	223,962
Accumulated deficit	(223,447)	(206,036)
Total stockholders' equity	12,221	17,974
Total liabilities and stockholders' equity	$ 24,842	$ 34,215

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Dec. 31, 2023	Dec. 31, 2022
Statement of Financial Position [Abstract]
Preferred stock, par value	$ 0.001	$ 0.001
Preferred stock, shares authorized	15,000,000	15,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized	500,000,000	500,000,000
Common stock, shares issued	19,468,180	6,466,294
Common stock, shares outstanding	19,468,180	6,466,294

CONSOLIDATED STATEMENTS OF OPER

CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Income Statement [Abstract]
Royalty revenue		$ 3,114
Revenue from Contract with Customer, Product and Service [Extensible List]	us-gaap:RoyaltyMember	us-gaap:RoyaltyMember
Operating expenses:
Research and development	$ (17,107)	$ (17,882)
General and administrative	(11,771)	(13,873)
Loss from operations	(28,878)	(28,641)
Other income (expense):
Other income (expense) from continuing operations, net	578	(4,027)
Gain related to sale of non-financial asset	9,650
Gain on extinguishment of liability related to sale of royalties		37,182
Milestone income related to sale of royalties		2,500
Net (loss) income from continuing operations	(18,650)	7,014
Discontinued operations:
Income from discontinued operations	1,239	1,013
Net (loss) income	$ (17,411)	$ 8,027
Net (loss) income per share:
Basic	$ (1.42)	$ 1.57
Diluted	$ (1.42)	$ 1.57
Shares used in calculation:
Basic	12,234,661	5,100,310
Diluted	12,234,661	5,102,914

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) income	$ (17,411)	$ 8,027
Adjustments to reconcile (loss) income to net cash used in operating activities:
Stock-based compensation	2,193	1,802
Depreciation and amortization	567	901
Loss on disposal of property and equipment		47
Non-cash interest expense and other	10	3,239
Gain on extinguishment of liability related to sale of royalties		(37,182)
Changes in operating assets and liabilities:
Royalty receivable	2,500	1,164
Prepaid expenses and other current assets	153	355
Operating lease right-of-use asset	422	653
Accounts payable, accrued compensation and other liabilities	518	(394)
Long-term operating lease liability	(682)	366
Net cash used in operating activities	(11,730)	(21,022)
Investing Activities
Purchases of property and equipment		(29)
Net cash used in investing activities		(29)
Financing Activities
Payments of long-term debt, including fees	(3,467)	(12,267)
Repayments under liability related to sale of royalties		(6,779)
Value of equity awards withheld for tax liability	(10)	(4)
Proceeds from exercises of warrants	3,047
Proceeds from milestones related to sale of royalties		10,000
Transaction costs for milestones related to sale of royalties		(500)
Proceeds from issuance of common stock and prefunded warrants	6,428	6,934
Net cash provided by (used in) financing activities	5,998	(2,616)
(Decrease) in cash and cash equivalents	(5,732)	(23,667)
Cash and cash equivalents at beginning of period	22,636	46,303
Cash and cash equivalents at end of period	16,904	22,636
Supplemental Cash Flow Information [Abstract]
Warrant modification - incremental value	$ 2,080
Change in right-of-use asset and lease liability from lease remeasurement		$ 4,372

CONSOLIDATED STATEMENT OF CHANG

CONSOLIDATED STATEMENT OF CHANGES IN STOCKHOLDERS' EQUITY - USD ($) $ in Thousands		Total	Common Stock	Common Stock Purchase Agreement Lincoln Park	Additional Paid-In Capital	Accumulated Deficit
Balance at Dec. 31, 2021		$ 1,216	$ 47		$ 215,232	$ (214,063)
Balance (in shares) at Dec. 31, 2021			4,898,143
Common stock issued upon vesting of restricted stock units and exercised stock options		(5)			(5)
Common stock issued upon vesting of restricted stock units and exercised stock options (in shares)			16,810
Commitment shares issued/ proceeds from issuance of common stock		6,934	$ 1		6,933
Commitment shares issued/ proceeds from issuance of common stock (in shares)			1,452,065	99,276
Stock-based compensation		1,802			1,802
Net income (loss) for the period		8,027				8,027
Balance at Dec. 31, 2022		17,974	$ 48		223,962	(206,036)
Balance (in shares) at Dec. 31, 2022			6,466,294
Common stock issued upon vesting of restricted stock units and exercised stock options		(10)			(10)
Common stock issued upon vesting of restricted stock units and exercised stock options (in shares)			96,804
Commitment shares issued/ proceeds from issuance of common stock		6,428	$ 9		6,419
Commitment shares issued/ proceeds from issuance of common stock (in shares)			9,095,430
Proceeds from warrant inducement, net of issuance cost	[1]	967	$ 4		963
Proceeds from warrant inducement, net of issuance cost ( in shares)	[1]		3,809,652
Warrant modification - incremental fair value		2,080			2,080
Stock-based compensation		2,193			2,193
Net income (loss) for the period		(17,411)				(17,411)
Balance at Dec. 31, 2023		$ 12,221	$ 61		$ 235,607	$ (223,447)
Balance (in shares) at Dec. 31, 2023			19,468,180

[1] (1) Includes gross proceeds of $ 3.3 million less issuance costs of $ 2.3 million, which includes $ 2.1 million warrant modification incremental fair value.

CONSOLIDATED STATEMENT OF CHA_2

CONSOLIDATED STATEMENT OF CHANGES IN STOCKHOLDERS' EQUITY (Parenthetical) $ in Thousands	12 Months Ended
	Dec. 31, 2023 USD ($)
Statement of Stockholders' Equity [Abstract]
Gross proceeds	$ 3,300
Issuance of costs	2,300
Warrant modification - incremental fair value	$ 2,080

Nature of Business and Signific

Nature of Business and Significant Accounting Policies	12 Months Ended
Nature of Business and Significant Accounting Policies	Dec. 31, 2023
Accounting Policies [Abstract]
Nature of Business and Significant Accounting Policies	Note 1. Nature of Business and Significant Accounting Policies Organization and Liquidity Aptevo Therapeutics Inc. (Aptevo, we, us, or the Company) is a clinical-stage, research and development biotechnology company focused on developing novel immunotherapy candidates for the treatment of different forms of cancer. We have developed two versatile and enabling platform technologies for rational design of precision immune modulatory drugs. Our clinical candidates, APVO436 and ALG.APV-527, and preclinical candidates, APVO603 and APVO711, were developed using our ADAPTIR modular protein technology platform. Our preclinical candidate APVO442 was developed using our ADAPTIR-FLEX modular protein technology platform. We are currently trading on the Nasdaq Capital Market under the symbol “APVO.” The accompanying consolidated financial statements have been prepared on a basis that assumes we will continue as a going concern and which contemplates the realization of assets, and satisfaction of liabilities, and commitments in the normal course of business. For the year ended December 31, 2023, we had net loss of $ 17.4 million. We had an accumulated deficit of $ 223.4 million as of December 31, 2023. For the year ended December 31, 2023, net cash used in our operating activities was $ 11.7 million. We have suffered recurring losses from operations and negative cash flows from operating activities. When considered in aggregate, these factors raise substantial doubt about our ability to continue as a going concern for the one-year period from the date of issuance of these financial statements. We will need to raise additional funds to support our operating and capital needs in addition to our existing cash resources, cash to be generated from future milestones related to IXINITY sales and regulatory approvals achieved by Medexus Pharmaceuticals ("Medexus"), and exercise of warrants. We may choose to raise additional funds to support our operating and capital needs in the future. We continue to face significant challenges and uncertainties and, as a result, our available capital resources may be consumed more rapidly than currently expected due to: (a) changes we may make to the business that affect ongoing operating expenses; (b) changes we may make in our business strategy; (c) changes we may make in our research and development spending plans; (d) whether and to what extent expected milestones are received from Medexus with respect to IXINITY; (e) whether and to what extent future milestone payments are received under our Royalty Purchase Agreement; (f) macroeconomic conditions such as rising interest rates, inflation and costs; and (g) other items affecting our forecasted level of expenditures and use of cash resources. We may obtain additional funding through our existing equity Purchase Agreement with Lincoln Park or attempt to obtain other public or private financing, collaborative or licensing arrangements with strategic partners, or through credit lines or other debt financing sources to increase the funds available to fund operations. However, we may not be able to secure such funding in a timely manner or on favorable terms, if at all. Furthermore, if we issue equity or debt securities to raise additional funds, our existing stockholders may experience dilution, and the new equity or debt securities may have rights, preferences, and privileges senior to those of our existing stockholders. If we raise additional funds through collaboration, licensing, or other similar arrangements, it may be necessary to relinquish valuable rights to our potential products or proprietary technologies, or grant licenses on terms that are not favorable to us. Without additional funds, we may be forced to delay, scale back, or eliminate some of our research and development activities or other operations and potentially delay product development in an effort to provide sufficient funds to continue our operations. If any of these events occurs, our ability to achieve our development goals may be adversely affected. Given the continuing global economic and geopolitical climate, including rising interest rates and stock market volatility, we may experience delays or difficulties in the financing environment and raising capital due to economic uncertainty. Basis of Presentation The accompanying consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles (GAAP). These consolidated financial statements include all adjustments, which include normal recurring adjustments, necessary for the fair presentation of the Company’s financial position. The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from these estimates and changes in these estimates are recorded when known. The consolidated financial statements include the accounts of the Company and our wholly owned subsidiary, Aptevo Research and Development LLC. All intercompany balances and transactions have been eliminated. All intercompany balances and transactions have been eliminated. Significant Accounting Policies Use of Estimates The preparation of financial statements in conformity with GAAP requires estimates and assumptions that affect the reported amounts of assets and liabilities, revenues and expenses, and related disclosures of contingent liabilities in the consolidated financial statements and accompanying notes. Estimates are used for, but not limited to, clinical accruals, useful lives of equipment, commitments and contingencies, stock-based compensation, and incremental borrowing rate (IBR) used for our lease. Given the global economic and geopolitical climate, these estimates are becoming more challenging, and actual results could differ materially from those estimates. Cash Equivalents Cash equivalents are highly liquid investments with a maturity of 90 days or less at the date of purchase and include time deposits and investments in money market funds with commercial banks and financial institutions. Concentrations of Credit Risk Financial instruments that potentially subject Aptevo to concentrations of credit risk consist primarily of cash and cash equivalents, certain investments and royalty and milestone receivable. Aptevo places its cash and cash equivalents with high quality financial institutions and may maintain cash balances in excess of insured limits. Management believes that the financial risks associated with its cash and cash equivalents are minimal. Property and Equipment Property and equipment are stated at cost. Depreciation is computed using the straight-line method over the following estimated useful lives: Furniture and equipment 7 - 10 years Software and hardware 3 - 5 years or product life Leasehold improvements Lesser of the asset life or the remaining lease term Upon retirement or sale, the cost of assets disposed of and the related accumulated depreciation are removed from the accounts and any resulting gain or loss is credited or charged to operations. Repairs and maintenance costs are expensed as incurred. Leases We determine if an arrangement is a lease at inception date. Leases are to be classified as finance or operating leases at the lease commencement date, which affects the classification of expense recognition in the consolidated statement of operations. Right-of-use assets represent the right to use an underlying asset for the lease term and lease liabilities represent the obligation to make lease payments, as agreed to in the lease. Operating lease liabilities and the corresponding right-of-use assets are recognized based on the present value of the future minimum lease payments over the lease term at commencement date. An operating right-of-use asset is measured as the amount of the initial measurement of the lease liability, adjusted for prepaid or accrued lease payments, the remaining balance of any lease incentive received, unamortized initial direct costs, and any impairment of the right-of-use asset. The initial measurement of the lease liabilities and right-to-use assets of finance leases is the same as for operating leases. We include options to extend the lease and certain termination options in our lease liability and right-of-use asset when it is reasonably certain that we will exercise those options. As our existing leases do not contain an implicit interest rate, we estimate our IBR based on information available at commencement date in determining the present value of future payments. Due to the significant judgment involved and the complex analysis needed to determine this discount rate, we engaged a third-party valuation specialist to advise us in our determination of our IBR for the initial adoption of the standard and subsequent amendment of our office lease. Lease expense for operating leases is recognized on a straight-line basis over the lease term as part of our selling, general and administrative expenses and our research and development expenses on our consolidated statements of operations. Lease expense for financing leases consists of amortization of the right-of-use asset and interest on the lease liability as part of our research and development expenses on our consolidated statements of operations. Fair Value of Financial Instruments We measure and record cash equivalents at fair value in the accompanying financial statements. 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 principal 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. The carrying amounts of our short-term financial instruments, which include cash and cash equivalents, royalty and milestone receivable and accounts payable, approximate their fair value due to their short maturities. Debt Extinguishment On March 29, 2023, we used a portion of the proceeds from our Purchase Agreement with XOMA to fully repay the $ 2.8 million outstanding principal balance of our MidCap debt, and $ 0.3 million in exit fees. The pre-payment was not considered an amendment to our Credit Agreement (as defined below) since we were required to fully repay the remaining principal balance if we sold our IXINITY deferred payment stream and milestones. Royalty Revenue We recognized revenue in accordance with ASC 606 - Revenue from Contracts with Customers . Under ASC 606, an entity recognizes revenue when its customer obtains control of promised goods or services, in an amount that reflects the consideration that the entity expects to receive in exchange for those goods or services. To determine revenue recognition for arrangements that an entity determines are within the scope of ASC 606, the entity performs the following five steps: (i) identify the contract(s) with a customer; (ii) identify the performance obligations in the contract; (iii) determine the transaction price; (iv) allocate the transaction price to the performance obligations in the contract; and (v) recognize revenue when (or as) the entity satisfies a performance obligation. RUXIENCE Royalty Revenue Aptevo’s royalty revenue was exclusively related to royalties on Pfizer’s net sales of RUXIENCE. We did not recognize royalty revenue for the year ended December 31, 2023. Royalty revenue for the period covered by this report reflects revenue recorded only in the first quarter of 2022 due to our Amendment to Royalty Purchase Agreement with HCR (see Note 9). As a result of the Amendment to Royalty Purchase Agreement, we ceased reporting as royalty revenue, royalties paid by Pfizer to HCR related to Pfizer’s sales of RUXIENCE. We recognized royalty revenue under ASC 606, which provides revenue recognition constraints by requiring the recognition of revenue at the later of the following: (1) when the subsequent sale or usage occurs or (2) when the performance obligation to which some or all of the sales-based or usage-based royalty has been allocated has been satisfied (or partially satisfied). We satisfied our performance obligation prior to the period covered by this report, specifically in May 2011 when the original Collaboration and License Agreement between Trubion Pharmaceuticals and Wyeth was amended to remove the exclusivity/non-compete restrictions so that Pfizer could develop a CD20 biosimilar product in exchange for a one-time payment of $ 2.5 million and future royalties of 2.5 % on any CD20 biosimilar product commercialized by Pfizer in the future. We do not have future performance obligations under this agreement. We applied the royalty recognition constraint required under the guidance for sales-based royalties, which requires a sales-based royalty to be recorded no sooner than the underlying sale. Therefore, royalties on sales of products commercialized by Pfizer were recognized in the quarter the product is sold. Given the royalty revenues were based on 2.5 % of global net sales of RUXIENCE, the considerations were considered variable. Pfizer generally reported sales information to us within 60 days of quarter end. Unless we received finalized sales information for the respective quarter, we estimated the expected royalty proceeds based on an analysis of historical experience, analyst expectations, interim data provided by Pfizer, including their publicly announced sales, and other publicly available information. Differences between actual and estimated royalty revenues were adjusted for in the period in which they became known, typically the following quarter. Aptevo did not record revenue for the year ended December 31, 2023 due to our Amendment to Royalty Purchase Agreement. Revenue recorded for the year ended December 31, 2022 represents actual royalty revenue given the timing of RUXIENCE sales reports received from Pfizer. There was no significant financing component to the contract. Research and Development Expenses Research and development expenses are expensed as incurred. Research and development costs primarily consist of internal labor costs, fees paid to outside service providers and the costs of materials used in clinical trials and research and development. Other research and development expenses include facility, maintenance, and related support expenses. A substantial portion of Aptevo’s preclinical studies and all of its clinical studies have been performed by third-party CROs. The Company reviews the activities performed by the CROs each period. For preclinical studies, the significant factors used in estimating accruals include the percentage of work completed to date and contract milestones achieved. For clinical study expenses, the significant factors used in estimating accruals include the number of patients enrolled and services provided but not yet invoiced. The Company’s estimates are highly dependent upon the timeliness and accuracy of the data provided by its CROs regarding the status of each program and total program spending and adjustments are made when deemed necessary. General and Administrative Expenses General and administrative expenses consist primarily of personnel-related costs and professional fees in support of our executive, business development, finance, accounting, information technology, legal and human resource functions. Other costs include facility costs not otherwise included in research and development expense. Stock-Based Compensation We measure and recognize compensation expense for restricted stock units (RSUs), and stock options granted to our employees and directors based on the fair value of the awards as of the date of grant. The fair value of stock options is estimated at the date of grant using the Black-Scholes option pricing model that requires management to apply judgment and make estimates, including: • the expected term of the stock option award, which we calculate using the simplified method, as we have insufficient historical information regarding our stock options to provide a basis for an estimate; • the expected volatility of our underlying common stock, which we estimate based on the historical volatility of the historical and implied future volatility of our common stock; • the risk-free interest rate, which we based on the yield curve of U.S. Treasury securities with periods commensurate with the expected term of the options being valued; • the expected dividend yield, which we estimate to be zero based on the fact that we have never paid cash dividends and have no present intention to pay cash dividends; and • the fair value of our common stock on the date of grant. Stock-based compensation expense for RSUs is recognized on a straight-line basis over the vesting period of the respective award. Stock-based compensation expense for our stock options, both converted and Aptevo granted, is recognized on a straight-line basis over the vesting period of the respective award. We routinely evaluate the appropriateness of the forfeiture rate based on actual forfeiture experience, analysis of employee turnover, and expectations of future option exercise behavior. Income Taxes Income taxes are accounted for using the liability method. Deferred tax assets and liabilities are recognized for future tax consequences attributable to differences between financial statement carrying amounts of existing assets and liabilities and their respective tax bases and net operating loss and tax credit carry forwards. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the year in which those temporary differences are expected to be recovered or settled. Aptevo’s ability to realize deferred tax assets depends upon future taxable income, as well as the limitations discussed below. For financial reporting purposes, a deferred tax asset must be reduced by a valuation allowance if it is more likely than not that some portion or all of the deferred tax assets will not be realized prior to expiration. Aptevo considers historical and future taxable income, future reversals of existing taxable temporary differences, taxable income in prior carryback years, and ongoing tax planning strategies in assessing the need for valuation allowances. In general, if Aptevo determines that it is more likely than not to realize more than the recorded amounts of net deferred tax assets in the future, Aptevo will reverse all or a portion of the valuation allowance established against its deferred tax assets, resulting in a decrease to the provision for income taxes in the period in which the determination is made. Likewise, if Aptevo determines that it is not more likely than not to realize all or part of the net deferred tax asset in the future, Aptevo will establish a valuation allowance against deferred tax assets, with an offsetting increase to the provision for income taxes, in the period in which the determination is made. Because tax laws are complex and subject to different interpretations, significant judgment is required. As a result, Aptevo makes certain estimates and assumptions, in (1) calculating Aptevo’s income tax expense, deferred tax assets and deferred tax liabilities, (2) determining any valuation allowance recorded against deferred tax assets and (3) evaluating the amount of unrecognized tax benefits, as well as the interest and penalties related to such uncertain tax positions. Aptevo’s estimates and assumptions may differ significantly from tax benefits ultimately realized. Segment Reporting Operating segments are identified as components of an entity about which separate discrete financial information is available for evaluation by the chief operating decision maker (CODM), or decision-making group, in making decisions on how to allocate resources and assess performance. The Company's CODM is the Chief Executive Officer, who views the Company's operations as one operating segment, which is discovery and development of novel oncology therapeutics.

Discontinued Operations

Discontinued Operations	12 Months Ended
Discontinued Operations	Dec. 31, 2023
Discontinued Operations and Disposal Groups [Abstract]
Discontinued Operations	Note 2. Discontinued Operations The accompanying consolidated financial statements include discontinued operations from the sale of business products and segments. The following table represents the components attributable to income from discontinued operations in the consolidated statements of operations (in thousands): For the Year Ended December 31, 2023 2022 Deferred payments from Medexus $ 523 $ 1,013 Gain on contingent consideration from release of escrow related to sale of Aptevo BioTherapeutics 163 — Gain on contingent consideration from Kamada 553 — Income from discontinued operations $ 1,239 $ 1,013 For the year ended December 31, 2023, we collected $ 0.5 million in deferred payments from Medexus related to IXINITY sales and $ 0.2 million related to funds released from escrow from the sale of Aptevo BioTherapeutics in 2020. Additionally, we received $ 0.6 million related to the sale of hyperimmune business to Saol (later acquired by Kamada, Ltd.) as a result of the collection of certain accounts receivable. For the year ended December 31, 2022, we collected $ 1.0 million in deferred payment from Medexus related to IXINITY sales.

XOMA Transaction

XOMA Transaction	12 Months Ended
XOMA Transaction	Dec. 31, 2023
Related Party Transactions [Abstract]
XOMA Transaction	Note 3. XOMA Transaction On March 29, 2023, we entered into and closed a Purchase Agreement with XOMA pursuant to which we sold to XOMA our right, title and interest in and to all of the deferred payments and a portion of the milestone payments from Medexus under our 2020 LLC Purchase Agreement. Under the terms of our Purchase Agreement with XOMA, we received $ 9.6 million at closing (the “Closing Payment”) and an additional post-closing payment of $ 0.05 million (the “Post-Closing Payment”). In exchange for the Closing Payment, we sold to XOMA our right, title and interest to the following payments under the LLC Purchase Agreement: (i) 100 % of the Company’s entitlement to receive the deferred payments that may become due and payable following March 29, 2023 (including, for avoidance of doubt, any and all payments earned during Q1 2023), (ii) 25 % of the Company’s entitlement to receive the Canadian Approval Milestone Payment; and (iii) 50 % of the Company’s entitlement to receive the European Approval Milestone Payments and Net Sales Milestone Payment. We accounted for the $ 9.6 million Closing Payment and the $ 0.05 million post-closing payment from XOMA as other income in accordance with ASC 610-20 Other Income - Gains and Losses from the Derecognition of Nonfinancial Assets in the first quarter of 2023. Contractual rights sold to XOMA represent an intangible asset under ASC 610-20 Other Income - Gains and Losses from the Derecognition of Nonfinancial Assets for which XOMA bears all benefit and Aptevo has no obligations going forward. The transaction was considered a complete sale of a nonfinancial assets. Additionally, XOMA has no recourse against the Company for Medexus’ non-payment absent breach by the Company of its representations, warranties, and covenants in the LLC Purchase Agreement and Aptevo has no role in obtaining regulatory approvals or achieving net sales targets. The Company will continue to account for its portion of future milestones under our LLC Purchase Agreement with Medexus as contingent consideration under ASC 450-30 Gain Contingencies and will record income when proceeds are received.

Collaboration Agreements

Collaboration Agreements	12 Months Ended
Collaboration Agreements	Dec. 31, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Collaboration Agreements	Note 4. Collaboration Agreements Alligator Bioscience AB On July 20, 2017, our wholly owned subsidiary Aptevo Research and Development LLC (Aptevo R&D), entered into a collaboration and option agreement (the Collaboration Agreement) with Alligator Bioscience AB (Alligator), pursuant to which Aptevo and Alligator have been collaboratively developing ALG.APV-527, a lead bispecific antibody candidate simultaneously targeting 4-1BB (CD137), a member of the TNFR superfamily of a costimulatory receptor found on activated T cells, and 5T4, a tumor antigen widely overexpressed in a number of different types of cancer. We assessed the arrangement in accordance with ASC 606 and concluded that the contract counterparty, Alligator, is not a customer. As such the arrangement is not in the scope of ASC 606 and is instead treated as a collaborative agreement under ASC 808 – Collaborative Arrangements (ASC 808). In accordance with ASC 808, we concluded that because the Collaboration Agreement is a cost sharing agreement, there is no revenue. For the years ended December 31, 2023 and 2022, we recorded approximately $ 2.7 million and $ 1.7 million, which represent our 50 % cost share, in our research and development expense related to the Collaboration Agreement, respectively.

Fair Value Measurements

Fair Value Measurements	12 Months Ended
Fair Value Measurements	Dec. 31, 2023
Fair Value Disclosures [Abstract]
Fair Value Measurements	Note 5. Fair Value Measurements The Company’s estimates of fair value for financial assets and financial liabilities are based on the framework established in the fair value accounting guidance. The framework is based on the inputs used in valuation, gives the highest priority to quoted prices in active markets and requires that observable inputs be used in the valuations when available. The disclosure of fair value estimates in the fair value accounting guidance hierarchy is based on whether the significant inputs into the valuation are observable. In determining the level of the hierarchy in which the estimate is disclosed, the highest priority is given to unadjusted quoted prices in active markets and the lowest priority to unobservable inputs that reflect the Company’s significant market assumptions. The level in the fair value hierarchy within which the fair value measurement is reported is based on the lowest level input that is significant to the measurement in its entirety. The three levels of the hierarchy are as follows: Level 1— Quoted prices in active markets for identical assets and liabilities; Level 2— Inputs other than quoted prices in active markets, that are either directly or indirectly observable; and, Level 3— Unobservable inputs that are supported by little or no market activity, and that are significant to the fair value of the assets or liabilities. As of December 31, 2023 and 2022, we had $ 13.2 million and $ 21.6 . million in money market funds, respectively, which are classified as Level 1 investments. The carrying amounts of our money market funds approximate their fair value. As of December 31, 2023 and 2022, we did no t have any Level 2 or Level 3 assets or liabilities.

Cash and Cash Equivalents

Cash and Cash Equivalents	12 Months Ended
Cash and Cash Equivalents	Dec. 31, 2023
Cash and Cash Equivalents [Abstract]
Cash and Cash Equivalents	Note 6. Cash and Cash Equivalents The Company’s cash equivalents are highly liquid investments with a maturity of 90 days or less at the date of purchase and investments in money market funds. The following table shows our cash and cash equivalents as of December 31, 2023 and 2022: As of December 31, (in thousands) 2023 2022 Cash $ 3,732 $ 1,066 Cash equivalents 13,171 21,569 Total cash and cash equivalents $ 16,904 $ 22,635

Property and Equipment, Net

Property and Equipment, Net	12 Months Ended
Property and Equipment, Net	Dec. 31, 2023
Property, Plant and Equipment [Abstract]
Property and Equipment, Net	Note 7. Property and equipment, net Property and equipment consist of the following: For the Year Ended December 31, (in thousands) 2023 2022 Leasehold improvements $ 2,228 $ 2,228 Furniture and equipment 12,260 12,260 Property and equipment, gross 14,488 14,488 Less: Accumulated depreciation ( 13,593 ) ( 13,026 ) Total property and equipment, net $ 895 $ 1,462 Depreciation expense for the years ended December 31, 2023 and 2022 was $ 0.6 million and $ 0.9 million, respectively.

Debt

Debt	12 Months Ended
Debt	Dec. 31, 2023
Debt Disclosure [Abstract]
Debt	Note 8. Debt Credit Agreement On August 5, 2020, we entered into a Credit Agreement, with MidCap Financial (the "Credit Agreement"). The Credit Agreement provided us with up to $ 25.0 million of available borrowing capacity under a term loan facility. The full $ 25.0 million was drawn on the closing date of the Credit Agreement. On March 29, 2023, we used a portion of the proceeds from our Purchase Agreement with XOMA to fully repay the $ 2.8 million outstanding principal of our MidCap debt and payment of $ 0.3 million in exit fees. The pre-payment was not considered an amendment to our Credit Agreement since we were required to fully repay the remaining principal balance if we sold IXINITY deferred payment stream and milestones. As of December 31, 2023, we do no t have any outstanding debt on the balance sheet.

Liability Related to Sale of Ro

Liability Related to Sale of Royalties	12 Months Ended
Liability Related to Sale of Royalties	Dec. 31, 2023
Sale Of Royalties Liability Disclosure [Abstract]
Liability Related to Sale of Royalties	Note 9. Liability Related to Sale of Royalties On March 30, 2021, we entered into and closed a Royalty Purchase Agreement with HCR pursuant to which we sold to HCR the right to receive royalty payments made by Pfizer in respect of global net sales of RUXIENCE. Under the terms of the Royalty Purchase Agreement, we have received $ 47.5 million through December 31, 2023 ($ 35 million at closing and $ 12.5 million in milestone payments). Due to the nature of the transaction, which included a cap on HCR’s rate of return, we recorded a liability related to the proceeds received from HCR of $ 35.0 million, net of transaction costs of $ 1.1 million and the 2021 milestone payments in the collective amount of $ 10.0 million as an additional liability related to the sale of royalties on the consolidated balance sheet as of March 31, 2022 pursuant to ASC 470-10-25, Debt – Sales of Future Revenues or Various Other Measures of Income . On June 7, 2022, we entered into and closed an amendment to our Royalty Purchase Agreement, resulting in the Company recognizing a $ 37.2 million gain, which was the total balance of liability related to the sale of royalties on the closing date. The Amendment to Royalty Purchase Agreement eliminated all of our continuing involvement with the cash generating activities related to the royalties and removed all restrictions related to the rate of return and was therefore accounted for under ASC 610-20, Other Income — Gains and Losses from Derecognition of Nonfinancial Assets and ASC 405-20, Liabilities – Extinguishment of Liabilities . We received a 2022 milestone payment of $ 2.5 million on February 28, 2023. The proceeds from the 2022 milestone payment were recorded as other income in the consolidated statement of operations for the year ended December 31, 2022. Due to our Amendment to Royalty Purchase Agreement, we did not have any liability related to sale of royalties as of December 31, 2023. The following table presents the changes in the liability in the prior period related to the sale of royalties under the Royalty Purchase Agreement with HCR (in thousands): For the year ended December 31, 2022 Liability related to sale of royalties, beginning balance $ 31,045 Proceeds from sale of royalties, net of transaction costs — Proceeds from milestone payments, net of transaction costs 9,500 Non-cash interest expense 3,416 RUXIENCE royalties paid by Pfizer to HCR ( 6,779 ) Gain from extinguishment of liability related to sale of royalties ( 37,182 ) Liability related to sale of royalties, ending balance — Current portion of liability related to sale of royalties — Liability related to sale of royalties, non-current $ —

Leases and Contingencies

Leases and Contingencies	12 Months Ended
Leases and Contingencies	Dec. 31, 2023
Leases [Abstract]
Leases and Contingencies	Note 10. Leases and Contingencies Office Space Lease – Operating We have an operating lease related to our office and laboratory space in Seattle, Washington. This lease was amended in March 2019 to extend the term through April 2030 and provide two options to extend the lease term, each by five years , as well as a one-time option to terminate the lease in April 2023 , with nine months’ notice, or by July 2022. We had previously determined we should not include any periods after the termination option when evaluating this amendment as we were not reasonably certain to not exercise the option, therefore we recorded our liability through April 30, 2023. On May 26, 2022, we amended our office and laboratory lease to remove the one-time termination option. In exchange for removing the termination option, we received six months of free rent. As a result, we recorded an additional $ 4.4 million of lease liability and right-of-use asset on the consolidated balance sheet on the date of the amendment. As of December 31, 2023, we are not reasonably certain to exercise the two options to extend the lease term. Therefore, pursuant to our May 26, 2022 amendment, we recorded our lease liability through April 30, 2030. For the years ended December 31, 2023 and 2022, we recorded $ 0.8 million and $ 0.7 million, respectively, related to variable expense due to true ups of operating costs or real estate taxes. Equipment Leases - Operating and Financing As of December 31, 2023, we did no t have any operating or financing leases for equipment. Components of lease expense: For the year ended For the year ended (in thousands) 2023 2022 Operating lease cost $ 1,187 $ 1,277 Total lease cost $ 1,187 $ 1,277 Right-of-use assets acquired under operating leases: As of December 31, As of December 31, (in thousands) 2023 2022 Seattle office lease, including amendment 4,881 5,303 Total right-of-use assets $ 4,881 $ 5,303 Lease payments: For the year ended For the year ended (in thousands) 2023 2022 For operating leases $ 1,147 $ 895 Future minimum payments as of December 31, 2023 are as follows: (in thousands) 2024 1,376 2025 1,376 2026 1,376 2027 and beyond 4,587 Total future minimum lease payments 8,715 Less: imputed interest ( 2,636 ) Total $ 6,079 As of December 31, 2023, the long-term and current portion of the lease liabilities were $ 5.4 million and $ 0.7 million, respectively. As of December 31, 2022, the long-term and current portion of the lease liabilities were $ 6.1 million and $ 0.4 million, respectively. As of December 31, 2023, the weighted average remaining lease term and weighted discount rate for operating leases was 6.3 years and 12.03 %. As of December 31, 2022, the weighted average remaining lease term and weighted discount rate for operating leases was 7.3 years and 12.03 %.

Net Income (Loss) per Share

Net Income (Loss) per Share	12 Months Ended
Net Income (Loss) per Share	Dec. 31, 2023
Earnings Per Share [Abstract]
Net Income (Loss) per Share	Note 11. Net Income (Loss) per Share Basic net income (loss) per share is calculated by dividing the net income (loss) by the weighted-average number of common shares outstanding for the period. The weighted-average number of common shares outstanding includes the shares held in abeyance resulting from the exercise of warrants because there is no consideration required for delivery of shares. Diluted net income (loss) per share is computed by dividing the net income (loss) by the weighted-average number of common share equivalents outstanding for the period using the as-if converted method. For the purpose of this calculation, warrants, stock options and restricted stock units ("RSUs") are only included in the calculation of diluted net income (loss) per share when their effect is dilutive. We utilize the control number concept in the computation of diluted earnings per share to determine whether potential common stock instruments are dilutive. The control number used is income (loss) from continuing operations or income from discontinued operations. The control number concept requires that the same number of potentially dilutive securities applied in computing diluted earnings per share from continuing operations be applied to all other categories of income or loss, regardless of their anti-dilutive effect on such categories. Common stock equivalents include warrants, stock options and unvested RSUs. The following table presents the computation of basic and diluted net income (loss) per share (in thousands, except share and per share amounts): For the Year Ended December 31, 2023 2022 Net (loss) income from continuing operations $ ( 18,650 ) $ 7,014 Income from discontinued operations 1,239 1,013 Net (loss) income $ ( 17,411 ) $ 8,027 Basic and diluted net (loss) income per share from continuing operations: Basic $ ( 1.52 ) $ 1.38 Diluted $ ( 1.52 ) $ 1.37 Basic and diluted net income per share from discontinued operations: Basic $ 0.10 $ 0.20 Diluted $ 0.10 $ 0.20 Shares used in calculation Basic 12,234,661 5,100,310 Diluted 12,234,661 5,102,914 The following table represents all potentially dilutive shares: As of December 31, (in thousands, except for per share amounts) 2023 2022 Warrants 30,678 351 Outstanding options to purchase common stock 442 364 Unvested RSUs 279 224 We use the treasury stock method when determining dilutive shares. For the year ended December 31, 2023, the Company was in a net loss position, therefore the share number used to calculate diluted earnings per share is the same as the basic earnings per share. As of December 31, 2022, we determined RSUs were the only dilutive shares, therefore included in the diluted earnings per share calculation.

Equity

Equity	12 Months Ended
Equity	Dec. 31, 2023
Equity [Abstract]
Equity	Note 12. Equity Warrants - 2019 In March 2019, as part of a public offering, we issued warrants to purchase up to 1,725,000 shares of our common stock, 1,571,429 of which have an exercise price of $ 18.20 per share and have a five-year life, and 153,571 of pre-funded warrants with an exercise price of $ 0.14 per share. The pre-funded warrants had a ten-year life and would have expired on March 11, 2029 ; however, all of the pre-funded warrants were exercised in March 2019. We determined the warrants do not meet liability classification pursuant to ASC 480 – Distinguishing Liabilities from Equity . These are therefore included within equity on our consolidated balance sheets. For the year ended December 31, 2023 and 2022, the Company did no t have any of its warrants exercised. As of December 31, 2023 and 2022, there were warrants to purchase 350,589 shares of common stock outstanding, which expire in March 2024 . August 2023 Public Raise On August 4, 2023, we completed a public offering of common stock and warrant, as follows: • 2,221,550 shares of common stock at a price of $ 0.62 per share. • $ 0.62 per pre-funded warrant, to purchase up to 5,842,967 shares of common stock at an exercise price of $ 0.001 per share and will not expire prior to exercise. As of December 31, 2023, all pre-funded warrants have been exercised. • Series A and Series B common warrants to purchase up to an aggregate of 16,129,034 shares of common stock at an exercise price of $ 0.62 per share. The remaining 1,872,516 Series A and 58,000 Series B common warrants will expire on August 4, 2028 and February 4, 2025 , respectively. We received net proceeds of $ 4.3 million, net of transaction costs, as a result of this offering. In the fourth quarter of 2023, an aggregate of 14,198,518 Series A and Series B common warrants were exercised as part of our November 2023 warrant inducement agreement with certain holders of our common warrants. As of December 31, 2023, 3,809,652 shares of common stock have been issued with the remaining 10,388,866 shares held in abeyance and reserved for issuance at a later date. As of December 31, 2023, there were 1,872,516 Series A and 58,000 Series B common warrants outstanding with an exercise price of $ 0.62 per share. November 2023 Warrant Inducement On November 9, 2023, we entered into a warrant inducement agreement (the "Inducement Agreement") with certain holders of our Series A and Series B common warrants issued in connection with our August 2023 public offering. Pursuant to the Inducement Agreement, certain holders agreed to exercise for cash 6,192,001 Series A and 8,006,517 Series B common warrants at a reduced exercise price of $ 0.233 . The Company also agreed to issue new common stock warrants to purchase a number of shares of common stock equal to 200 % of the number of shares of common stock issued upon exercise of the existing Series A and Series B warrants as applicable. We received $ 3.3 million in gross proceeds from the exercise of these warrants less total issuance costs of $ 2.3 million. Issuance costs include banker and legal fees $ 0.2 million and non-cash warrant modification costs of $ 2.1 million. Because the modification represented a short-term inducement, modification accounting was only performed on the warrants that were actually exercised under the agreement. The Company recognized the $ 2.1 million modification date incremental value of the modified warrants and additional warrants issued as compared to the original warrants as an issuance cost of the warrant exercise. Additionally, pursuant to the Inducement Agreement, we issued an aggregate of 28,397,036 new Series A and new Series B warrants as follows: • 12,384,002 New Series A common warrants to purchase an aggregate of up to 12,384,002 shares of common stock at $ 0.233 per share, of which 6,192,001 Series A-1 common warrants are immediately exercisable and 6,192,001 Series A-2 common warrants will be exercisable at any time on or after the Stockholder Approval Date. The Series A-1 and Series A-2 common warrants have terms of four years and eight months , and five years , respectively. • 16,013,034 New Series B common warrants to purchase an aggregate of up to 16,013,034 shares of common stock at $ 0.233 per share, of which 8,006,517 Series B-1 common warrants are immediately exercisable and 8,006,517 Series B-2 common warrants will be exercisable at any time on or after the Stockholder Approval Date. The Series B-1 and Series B-2 common warrants have terms of fourteen months and twenty-four months , respectively. If the new warrants are exercised, we may receive up to an additional $ 6.6 million in gross proceeds. As of December 31, 2023, there were 6,192,001 Series A-1, 6,192,001 Series A-2, 8,006,517 Series B-1 and 8,006,517 Series B-2 common warrants outstanding with an exercise price of $ 0.233 per share. Number of Weighted-Average Exercise Price Weighted- Outstanding at December 31, 2022 350,589 $ 18.20 0.25 Issued 44,526,070 0.37 2.89 Exercised ( 14,198,518 ) 0.23 2.61 Outstanding at December 31, 2023 30,678,141 0.46 2.99 Exercisable at December 31, 2023 16,479,623 $ 0.66 2.78 Exercised with shares held in abeyance at December 31, 2023 10,388,866 - - Common warrants outstanding at December 31, 2023, includes 6,192,001 Series A-2 and 8,006,517 Series B-2 common warrants that became exercisable upon shareholder approval as of February 5, 2024 . Aptevo uses Black-Scholes valuation model for estimating the incremental fair value of the exchanged common warrants included in the Inducement Agreement. Set forth below are the assumptions used in valuing the common warrants issued: For the Year Ended December 31, 2023 Expected dividend yield 0.00 % Expected volatility 104.01 % Risk-free interest rate 5.40 % Expected average life of warrants 1.2 - 5 years Equity Distribution Agreement On December 14, 2020, we entered into an Equity Distribution Agreement with Piper Sandler. The Equity Distribution Agreement provided that, upon the terms and subject to the conditions set forth therein, we may issue and sell through Piper Sandler, acting as sales agent, shares of our common stock, $ 0.001 par value per share having an aggregate offering price of up to $ 50.0 million. This offering superseded and replaced the program we commenced in December 2017. We had no obligation to sell any such shares under the Equity Distribution Agreement. The sale of such shares of common stock by Piper Sandler would be effected pursuant to a Registration Statement on Form S-3 which we filed on December 14, 2020, and expired in December 2023. For the year ended December 31, 2023, we issued 730,913 shares of our common stock at an average share price of $ 2.26 under the Equity Distribution Agreement. We received $ 1.6 million in proceeds from issuance of these shares. For the year ended December 31, 2022, we issued 1,452,065 shares of our common stock at an average share price of $ 4.92 under the Equity Distribution Agreement. We received $ 7.0 million in proceeds from issuance of these shares. Lincoln Park Purchase Agreement On February 16, 2022, we entered into a Purchase Agreement (2022 Purchase Agreement) and a Registration Rights Agreement with Lincoln Park. The 2022 Purchase Agreement and Registration Rights Agreement replaced our 2018 Purchase Agreement and Registration Rights Agreement with Lincoln Park. Under the 2022 Purchase Agreement, Lincoln Park committed to purchase up to $ 35.0 million of our common stock over a 36-month period commencing after the satisfaction of certain conditions, which are within our control, as set forth in the Purchase Agreement. The purchase price per share will be based on prevailing market prices; provided, however, that the prevailing market price is not below $ 1.00 . We agreed to and issued 99,276 shares of our common stock to Lincoln Park for no cash consideration as an initial fee for its commitment to purchase shares of our common stock under the 2022 Purchase Agreement. For the year ended December 31, 2023, we issued 300,000 shares of our common stock to Lincoln Park under the 2022 Purchase Agreement and we received $ 0.5 million in proceeds from issuance of these shares. For the year ended December 31, 2022, we did no t issue any shares of common stock for cash consideration to Lincoln Park under the 2022 Purchase Agreement. Rights Plan On November 8, 2020, our Board of Directors (the "Board") approved and adopted a Rights Agreement (the "Rights Agreement"), dated as of November 8, 2020, by and between the Company and Broadridge Corporate Issuer Solutions, Inc., as rights agent, pursuant to which the Board declared a dividend of one preferred share purchase right (each, a "Right") for each outstanding share of the Company’s common stock held by stockholders as of the close of business on November 23, 2020. One Right also will be issued together with each Common Share issued by the Company after November 23, 2020, but before the Distribution Date (as defined below) (or the earlier redemption or expiration of the Rights) and, in certain circumstances, after the Distribution Date. When exercisable, each Right initially would represent the right to purchase from the Company one one-thousandth of a share of a newly-designated series of preferred stock , Series A Junior Participating Preferred Stock, par value $ 0.001 per share, of the Company. Subject to various exceptions, the Rights become exercisable in the event any person (excluding certain exempted or grandfathered persons) becomes the beneficial owner of ten percent ( 10 %) or more of the Company’s common stock without the approval of the Board. On November 2, 2023, we entered into Amendment No. 3 to the Rights Agreement and extended the expiration of such agreement to November 4, 2024 and changed the exercise price to $ 2.02 per one one-thousandth of a Series A Junior Participating Preferred Share, subject to adjustment. 2018 Stock Incentive Plan On June 1, 2018, at the 2018 Annual Meeting of the Stockholders, the Company’s stockholders approved a new 2018 Stock Incentive Plan (the "2018 SIP"), which replaced the Restated 2016 Plan on a go-forward basis. All stock options, RSUs or other equity awards granted subsequent to June 1, 2018 have been and will be issued out of the 2018 SIP, which has 0.3 million shares of Aptevo common stock authorized for issuance. The 2018 Plan became effective immediately upon stockholder approval at the 2018 Annual Meeting of the Stockholders. Any shares subject to outstanding stock awards granted under the 2016 SIP that (a) expire or terminate for any reason prior to exercise or settlement; (b) are forfeited because of the failure to meet a contingency or condition required to vest such shares or otherwise return to the Company; or (c) otherwise would have returned to the 2016 SIP for future grant pursuant to the terms of the 2016 Plan (such shares, the “Returning Shares”) will immediately be added to the share reserve under the 2018 SIP as and when such shares become Returning Shares, up to a maximum of 0.3 million shares. On June 7, 2022, at the 2022 Annual Meeting of Stockholders, our stockholders approved the Amended and Restated 2018 SIP to increase the number of shares authorized for issuance under the 2018 SIP by 0.5 million shares of common stock. As of December 31, 2023, there are approximately 0.1 million shares available to be granted under the 2018 SIP. Stock options and RSUs under the Amended and Restated 2018 SIP generally vest pro rata over a one-year or three-year period. Stock options terminate ten years from the grant date, though the specific terms of each grant are determined individually. The Company’s executive officers, members of our board of directors, and certain other employees and consultants may be awarded options and/or RSUs with different vesting criteria, and awards granted to non-employee directors will vest over a one-year period. Option exercise and RSU grant prices for new awards granted by the Company equal the closing price of the Company’s common stock on the Nasdaq Capital Market on the date of grant. Stock-Based Compensation Expense Stock-based compensation expense includes amortization of stock options and RSUs granted to employees and non-employees and has been reported in our consolidated statements of operations as follows: For the Year Ended December 31, (in thousands) 2023 2022 Research and development $ 684 $ 196 General and administrative 1,509 1,606 Total stock-based compensation expense $ 2,193 $ 1,802 The Company accounts for stock-based compensation by measuring the cost of employee services received in exchange for all equity awards granted based on the fair value of the award as of the grant date. The Company recognizes the compensation expense over the vesting period. All assumptions used to calculate the grant date fair value of non-employee equity awards are generally consistent with the assumptions used for equity awards granted to employees. In the event the Company terminates any of its consulting agreements, the unvested equity underlying the agreements would also be forfeited. Stock Options Aptevo utilizes the Black-Scholes valuation model for estimating the fair value of all stock options granted. Set forth below are the assumptions used in valuing the stock options granted: For the Year Ended December 31, 2023 2022 Expected dividend yield 0.00 % 0.00 % Expected volatility 103.63 % 106.24 % Risk-free interest rate 4.18 % 1.71 % Expected average life of options 5 years 5 years Management has applied an estimated forfeiture rate of 29 % and 30 % for the year ended December 31, 2023 and 2022, respectively. Expected volatility decreased, as our stock price fluctuated from a low of $ 0.17 to a high of $ 2.54 throughout the year ended December 31, 2023, compared to a low of $ 2.00 to a high of $ 8.42 throughout the year ended December 31, 2022. The following is a summary of option activity for the year ended December 31, 2023: Number of Weighted- Weighted- Outstanding at December 31, 2022 364,266 $ 15.77 7.39 Granted 103,965 2.11 — Exercised — — — Forfeited ( 26,705 ) 20.81 — Outstanding at December 31, 2023 441,526 12.80 7.37 Exercisable at December 31, 2023 248,346 $ 15.72 6.49 Vested and expected to vest at December 31, 2023 400,482 $ 13.66 7.22 As of December 31, 2023, we had $ 0.8 million of unrecognized compensation expense related to options expected to vest over a weighted average period of 0.7 years. The weighted-average grant date fair value per share of options granted during the years ended December 31, 2023 and 2022 was $ 1.68 and $ 4.36 , respectively. The aggregate intrinsic value of options exercised for the years ended December 31, 2023 and 2022 was $ 0 . The total fair value of stock options vested for the years ended December 31, 2023 and 2022 was $ 1.2 million and $ 1.3 million, respectively. The aggregate intrinsic value in the table above represents the total pretax intrinsic value (the difference between the closing stock price of Aptevo’s common stock on the last trading day of December 2023 and the exercise price, multiplied by the number of in the money options) that would have been received by the option holders had all the option holders exercised their options on the last trading day of the quarter. Restricted Stock Units The following is a summary of restricted stock activity for the year ended December 31, 2023: Number of Weighted Outstanding at December 31, 2022 223,775 $ 8.47 Granted 168,168 2.09 Vested ( 101,504 ) 8.84 Forfeited ( 11,306 ) 4.60 Outstanding at December 31, 2023 279,133 $ 4.65 Expected to Vest 279,133 $ 4.65 As of December 31, 2023, we had $ 0.8 million of unrecognized stock-based compensation expense related to RSUs expected to vest over a weighted average period of 1.2 years. As of December 31, 2022, we had $ 1.5 million of unrecognized stock-based compensation expense related to RSUs expected to vest over a weighted average period of 1.6 years. The fair value of each RSU has been determined to be the closing trading price of the Company’s common stock on the date of grant as quoted on the Nasdaq Capital Market.

401(K) Savings Plan

401(K) Savings Plan	12 Months Ended
401(K) Savings Plan	Dec. 31, 2023
Retirement Benefits [Abstract]
401(K) Savings Plan	Note 13. 401(k) Savings Plan Aptevo has established a defined contribution savings plan under Section 401(k) of the Internal Revenue Code, as amended. The 401(k) Plan covers all employees. Under the 401(k) Plan, employees may make elective salary deferrals. Aptevo currently provides for matching of qualified deferrals up to 50 % of 401(k) employee deferral contributions, based on a maximum employee deferral rate of 6 % of compensation. During the year ended December 31, 2023 and 2022, Aptevo’s related share of matching contributions was approximately $ 0.2 million.

Income Taxes

Income Taxes	12 Months Ended
Income Taxes	Dec. 31, 2023
Income Tax Disclosure [Abstract]
Income Taxes	Note 14. Income Taxes We did no t have an income tax benefit or income tax expense from continuing operations in the years ended December 31, 2023 and 2022. The components of income (loss) before income taxes were as follows (in thousands): Year ended December 31, (in thousands) 2023 2022 US $ ( 18,650 ) $ 7,014 Income (loss) from continuing operations before benefit from income taxes $ ( 18,650 ) $ 7,014 The tax effects of temporary differences that give rise to significant portions of the deferred tax assets and deferred tax liabilities are presented below: For the Year Ended December 31, (in thousands) 2023 2022 Federal losses carryforward $ 35,322 $ 32,793 Capitalized research expenditures 5,859 3,361 Intangible assets 151 195 Stock-based compensation 963 912 State losses carryforward 3,753 3,799 Other deferred tax assets 380 496 Other tax credits 6,121 4,852 Lease liabilities 1,280 1,371 Property and equipment 415 442 Gain related to sale of future royalties — 2,016 Deferred tax assets, gross 54,244 50,237 Valuation allowance ( 53,217 ) ( 49,113 ) Deferred tax assets, net of valuation 1,027 1,124 ROU assets ( 1,027 ) ( 1,124 ) Deferred tax liability ( 1,027 ) ( 1,124 ) Net deferred tax assets $ — $ — The Company evaluated the positive and negative evidence bearing upon the realizability of its deferred tax assets. Based on the Company’s history of operating losses, including a three-year cumulative loss position as of December 31, 2023, the Company has concluded that it is more likely than not that the benefit of its deferred tax assets will not be realized. Accordingly, the Company provided a full valuation allowance for its net deferred tax assets as of December 31, 2023 and 2022. The valuation allowance increased by $ 4.2 million during the year ended December 31, 2023. The increase in the valuation allowance during the year ended December 31, 2023 was due primarily to a an increase in deferred tax assets resulting from the orphan drug credit generated during the period, Section 174 capitalized research expenditures, and the generation of federal and state NOLs during the period. As of December 31, 2023 and 2022, we have recorded gross federal net operating losses (NOL) carryforwards of approximately $ 168.2 and $ 156.2 million, respectively, gross state NOL carryforwards of approximately $ 70.5 and $ 71.1 million, respectively, and tax credit carryforwards of $ 6.1 million and $ 4.9 million, respectively. Approximately $ 15.2 million of federal losses and credits would begin to expire in 2037 , while $ 153 million of federal losses may be carried forward indefinitely. The state net operating losses will begin to expire in varying periods. The Company completed an IRC Section 382/383 study on its federal and state tax attributes based on an ownership change that occurred during 2021. Based on the study, there are not any permanent limitations on our ability to use federal and state net operating loss carryforwards and tax credits. We may experience ownership changes in the future as a result of subsequent shifts in our stock ownership, some of which may be outside of our control. If an ownership change occurs in the future, our ability to use our net operating loss carryforwards and credits could be limited. The Company files income tax returns in the U.S. and several state jurisdictions and are open to review by taxing authorities for the 2016 tax filings and thereafter. We are subject to the accounting guidance for uncertain income tax positions. We believe that our income tax positions and deductions will be sustained on audit and do not anticipate any adjustments that will result in a material adverse effect on our financial condition, results of operations, or cash flow. Our policy for recording interest and penalties associated with audits and uncertain tax positions is to record such items as a component of income tax expense, and amounts recognized to date are insignificant. No uncertain income tax positions are recorded, and we do not expect our uncertain tax position to change during the next twelve months. The reconciliation of the federal statutory income tax rate to the Company’s effective income tax from continuing operations is as follows: Year ended December 31, 2023 2022 Federal tax at statutory rates 21.0 % 21.0 % State taxes, net of federal benefit - 0.2 % - 1.8 % Change in valuation allowance - 23.8 % - 12.5 % Tax credits 5.0 % - 15.3 % Permanent differences - 0.1 % 0.8 % Stock-based compensation - 2.6 % 10.1 % Other 0.7 % - 2.3 % Total income tax benefit 0.0 % 0.0 %

Subsequent Events

Subsequent Events	12 Months Ended
Subsequent Events	Dec. 31, 2023
Subsequent Events [Abstract]
Subsequent Events	Note 15. Subsequent Events On January 2 and February 15, 2024, holders of our August 2023 common warrants provided notice to release 2,864,870 and 1,130,000 shares of common stock from abeyance, respectively, which were then issued, leaving a remainder of 6,393,996 shares in abeyance. As of March 5, 2024, we have 23,472,436 shares of common stock issued and outstanding. On February 5, 2024, the Company held a Special Meeting of Stockholders (the “Special Meeting”), at which the Company’s stockholders: 1. Approved an amendment to the Company’s Amended and Restated Certificate of Incorporation to effect a reverse stock split of the Company’s common stock at a ratio in the range of 1-for-15 to 1-for-44 , with such ratio to be determined in the discretion of the Board of Directors of the Company (the “Board”) and with such reverse stock split to be effected at such time and date, if at all, as determined by the Board in its sole discretion (Proposal 1); 2. Approved, in accordance with Nasdaq Listing Rule 563(d), the issuance of more than 19.99 % of the Company’s outstanding common stock, par value $ 0.001 per share, issuable upon the exercise of New Series A-2 Warrants and New Series B-2 Warrants with the right for such potential exercise to occur immediately following the date upon which stockholders approved this proposal (Proposal 2); and 3. Approved an authorization to adjourn the Special Meeting, if necessary or appropriate, to solicit additional proxies if there are not sufficient votes in favor of Proposal 1 or Proposal 2.

Nature of Business and Signif_2

Nature of Business and Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2023
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles (GAAP). These consolidated financial statements include all adjustments, which include normal recurring adjustments, necessary for the fair presentation of the Company’s financial position. The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from these estimates and changes in these estimates are recorded when known. The consolidated financial statements include the accounts of the Company and our wholly owned subsidiary, Aptevo Research and Development LLC. All intercompany balances and transactions have been eliminated. All intercompany balances and transactions have been eliminated.
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with GAAP requires estimates and assumptions that affect the reported amounts of assets and liabilities, revenues and expenses, and related disclosures of contingent liabilities in the consolidated financial statements and accompanying notes. Estimates are used for, but not limited to, clinical accruals, useful lives of equipment, commitments and contingencies, stock-based compensation, and incremental borrowing rate (IBR) used for our lease. Given the global economic and geopolitical climate, these estimates are becoming more challenging, and actual results could differ materially from those estimates.
Cash Equivalents	Cash Equivalents Cash equivalents are highly liquid investments with a maturity of 90 days or less at the date of purchase and include time deposits and investments in money market funds with commercial banks and financial institutions.
Concentrations of Credit Risk	Concentrations of Credit Risk Financial instruments that potentially subject Aptevo to concentrations of credit risk consist primarily of cash and cash equivalents, certain investments and royalty and milestone receivable. Aptevo places its cash and cash equivalents with high quality financial institutions and may maintain cash balances in excess of insured limits. Management believes that the financial risks associated with its cash and cash equivalents are minimal.
Property and Equipment	Property and Equipment Property and equipment are stated at cost. Depreciation is computed using the straight-line method over the following estimated useful lives: Furniture and equipment 7 - 10 years Software and hardware 3 - 5 years or product life Leasehold improvements Lesser of the asset life or the remaining lease term Upon retirement or sale, the cost of assets disposed of and the related accumulated depreciation are removed from the accounts and any resulting gain or loss is credited or charged to operations. Repairs and maintenance costs are expensed as incurred.
Leases	Leases We determine if an arrangement is a lease at inception date. Leases are to be classified as finance or operating leases at the lease commencement date, which affects the classification of expense recognition in the consolidated statement of operations. Right-of-use assets represent the right to use an underlying asset for the lease term and lease liabilities represent the obligation to make lease payments, as agreed to in the lease. Operating lease liabilities and the corresponding right-of-use assets are recognized based on the present value of the future minimum lease payments over the lease term at commencement date. An operating right-of-use asset is measured as the amount of the initial measurement of the lease liability, adjusted for prepaid or accrued lease payments, the remaining balance of any lease incentive received, unamortized initial direct costs, and any impairment of the right-of-use asset. The initial measurement of the lease liabilities and right-to-use assets of finance leases is the same as for operating leases. We include options to extend the lease and certain termination options in our lease liability and right-of-use asset when it is reasonably certain that we will exercise those options. As our existing leases do not contain an implicit interest rate, we estimate our IBR based on information available at commencement date in determining the present value of future payments. Due to the significant judgment involved and the complex analysis needed to determine this discount rate, we engaged a third-party valuation specialist to advise us in our determination of our IBR for the initial adoption of the standard and subsequent amendment of our office lease. Lease expense for operating leases is recognized on a straight-line basis over the lease term as part of our selling, general and administrative expenses and our research and development expenses on our consolidated statements of operations. Lease expense for financing leases consists of amortization of the right-of-use asset and interest on the lease liability as part of our research and development expenses on our consolidated statements of operations.
Fair Value of Financial Instruments	Fair Value of Financial Instruments We measure and record cash equivalents at fair value in the accompanying financial statements. 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 principal 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. The carrying amounts of our short-term financial instruments, which include cash and cash equivalents, royalty and milestone receivable and accounts payable, approximate their fair value due to their short maturities.
Debt Extinguishment	Debt Extinguishment On March 29, 2023, we used a portion of the proceeds from our Purchase Agreement with XOMA to fully repay the $ 2.8 million outstanding principal balance of our MidCap debt, and $ 0.3 million in exit fees. The pre-payment was not considered an amendment to our Credit Agreement (as defined below) since we were required to fully repay the remaining principal balance if we sold our IXINITY deferred payment stream and milestones.
Royalty Revenue	Royalty Revenue We recognized revenue in accordance with ASC 606 - Revenue from Contracts with Customers . Under ASC 606, an entity recognizes revenue when its customer obtains control of promised goods or services, in an amount that reflects the consideration that the entity expects to receive in exchange for those goods or services. To determine revenue recognition for arrangements that an entity determines are within the scope of ASC 606, the entity performs the following five steps: (i) identify the contract(s) with a customer; (ii) identify the performance obligations in the contract; (iii) determine the transaction price; (iv) allocate the transaction price to the performance obligations in the contract; and (v) recognize revenue when (or as) the entity satisfies a performance obligation. RUXIENCE Royalty Revenue Aptevo’s royalty revenue was exclusively related to royalties on Pfizer’s net sales of RUXIENCE. We did not recognize royalty revenue for the year ended December 31, 2023. Royalty revenue for the period covered by this report reflects revenue recorded only in the first quarter of 2022 due to our Amendment to Royalty Purchase Agreement with HCR (see Note 9). As a result of the Amendment to Royalty Purchase Agreement, we ceased reporting as royalty revenue, royalties paid by Pfizer to HCR related to Pfizer’s sales of RUXIENCE. We recognized royalty revenue under ASC 606, which provides revenue recognition constraints by requiring the recognition of revenue at the later of the following: (1) when the subsequent sale or usage occurs or (2) when the performance obligation to which some or all of the sales-based or usage-based royalty has been allocated has been satisfied (or partially satisfied). We satisfied our performance obligation prior to the period covered by this report, specifically in May 2011 when the original Collaboration and License Agreement between Trubion Pharmaceuticals and Wyeth was amended to remove the exclusivity/non-compete restrictions so that Pfizer could develop a CD20 biosimilar product in exchange for a one-time payment of $ 2.5 million and future royalties of 2.5 % on any CD20 biosimilar product commercialized by Pfizer in the future. We do not have future performance obligations under this agreement. We applied the royalty recognition constraint required under the guidance for sales-based royalties, which requires a sales-based royalty to be recorded no sooner than the underlying sale. Therefore, royalties on sales of products commercialized by Pfizer were recognized in the quarter the product is sold. Given the royalty revenues were based on 2.5 % of global net sales of RUXIENCE, the considerations were considered variable. Pfizer generally reported sales information to us within 60 days of quarter end. Unless we received finalized sales information for the respective quarter, we estimated the expected royalty proceeds based on an analysis of historical experience, analyst expectations, interim data provided by Pfizer, including their publicly announced sales, and other publicly available information. Differences between actual and estimated royalty revenues were adjusted for in the period in which they became known, typically the following quarter. Aptevo did not record revenue for the year ended December 31, 2023 due to our Amendment to Royalty Purchase Agreement. Revenue recorded for the year ended December 31, 2022 represents actual royalty revenue given the timing of RUXIENCE sales reports received from Pfizer. There was no significant financing component to the contract.
Research and Development expense	Research and Development Expenses Research and development expenses are expensed as incurred. Research and development costs primarily consist of internal labor costs, fees paid to outside service providers and the costs of materials used in clinical trials and research and development. Other research and development expenses include facility, maintenance, and related support expenses. A substantial portion of Aptevo’s preclinical studies and all of its clinical studies have been performed by third-party CROs. The Company reviews the activities performed by the CROs each period. For preclinical studies, the significant factors used in estimating accruals include the percentage of work completed to date and contract milestones achieved. For clinical study expenses, the significant factors used in estimating accruals include the number of patients enrolled and services provided but not yet invoiced. The Company’s estimates are highly dependent upon the timeliness and accuracy of the data provided by its CROs regarding the status of each program and total program spending and adjustments are made when deemed necessary.
General and Administrative Expenses	General and Administrative Expenses General and administrative expenses consist primarily of personnel-related costs and professional fees in support of our executive, business development, finance, accounting, information technology, legal and human resource functions. Other costs include facility costs not otherwise included in research and development expense.
Stock-Based Compensation	Stock-Based Compensation We measure and recognize compensation expense for restricted stock units (RSUs), and stock options granted to our employees and directors based on the fair value of the awards as of the date of grant. The fair value of stock options is estimated at the date of grant using the Black-Scholes option pricing model that requires management to apply judgment and make estimates, including: • the expected term of the stock option award, which we calculate using the simplified method, as we have insufficient historical information regarding our stock options to provide a basis for an estimate; • the expected volatility of our underlying common stock, which we estimate based on the historical volatility of the historical and implied future volatility of our common stock; • the risk-free interest rate, which we based on the yield curve of U.S. Treasury securities with periods commensurate with the expected term of the options being valued; • the expected dividend yield, which we estimate to be zero based on the fact that we have never paid cash dividends and have no present intention to pay cash dividends; and • the fair value of our common stock on the date of grant. Stock-based compensation expense for RSUs is recognized on a straight-line basis over the vesting period of the respective award. Stock-based compensation expense for our stock options, both converted and Aptevo granted, is recognized on a straight-line basis over the vesting period of the respective award. We routinely evaluate the appropriateness of the forfeiture rate based on actual forfeiture experience, analysis of employee turnover, and expectations of future option exercise behavior.
Income Taxes	Income Taxes Income taxes are accounted for using the liability method. Deferred tax assets and liabilities are recognized for future tax consequences attributable to differences between financial statement carrying amounts of existing assets and liabilities and their respective tax bases and net operating loss and tax credit carry forwards. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the year in which those temporary differences are expected to be recovered or settled. Aptevo’s ability to realize deferred tax assets depends upon future taxable income, as well as the limitations discussed below. For financial reporting purposes, a deferred tax asset must be reduced by a valuation allowance if it is more likely than not that some portion or all of the deferred tax assets will not be realized prior to expiration. Aptevo considers historical and future taxable income, future reversals of existing taxable temporary differences, taxable income in prior carryback years, and ongoing tax planning strategies in assessing the need for valuation allowances. In general, if Aptevo determines that it is more likely than not to realize more than the recorded amounts of net deferred tax assets in the future, Aptevo will reverse all or a portion of the valuation allowance established against its deferred tax assets, resulting in a decrease to the provision for income taxes in the period in which the determination is made. Likewise, if Aptevo determines that it is not more likely than not to realize all or part of the net deferred tax asset in the future, Aptevo will establish a valuation allowance against deferred tax assets, with an offsetting increase to the provision for income taxes, in the period in which the determination is made. Because tax laws are complex and subject to different interpretations, significant judgment is required. As a result, Aptevo makes certain estimates and assumptions, in (1) calculating Aptevo’s income tax expense, deferred tax assets and deferred tax liabilities, (2) determining any valuation allowance recorded against deferred tax assets and (3) evaluating the amount of unrecognized tax benefits, as well as the interest and penalties related to such uncertain tax positions. Aptevo’s estimates and assumptions may differ significantly from tax benefits ultimately realized. Segment Reporting Operating segments are identified as components of an entity about which separate discrete financial information is available for evaluation by the chief operating decision maker (CODM), or decision-making group, in making decisions on how to allocate resources and assess performance. The Company's CODM is the Chief Executive Officer, who views the Company's operations as one operating segment, which is discovery and development of novel oncology therapeutics.
Segment Reporting	Segment Reporting Operating segments are identified as components of an entity about which separate discrete financial information is available for evaluation by the chief operating decision maker (CODM), or decision-making group, in making decisions on how to allocate resources and assess performance. The Company's CODM is the Chief Executive Officer, who views the Company's operations as one operating segment, which is discovery and development of novel oncology therapeutics.

Nature of Business and Signif_3

Nature of Business and Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2023
Accounting Policies [Abstract]
Schedule of Estimated Useful Lives of Property and Equipment	Depreciation is computed using the straight-line method over the following estimated useful lives: Furniture and equipment 7 - 10 years Software and hardware 3 - 5 years or product life Leasehold improvements Lesser of the asset life or the remaining lease term

Discontinued Operations (Tables

Discontinued Operations (Tables)	12 Months Ended
Discontinued Operations (Tables)	Dec. 31, 2023
Discontinued Operations and Disposal Groups [Abstract]
Summary of Reconciliation of Carrying Amounts of Assets and Liabilities and Income (Loss) from Discontinued Operation	The following table represents the components attributable to income from discontinued operations in the consolidated statements of operations (in thousands): For the Year Ended December 31, 2023 2022 Deferred payments from Medexus $ 523 $ 1,013 Gain on contingent consideration from release of escrow related to sale of Aptevo BioTherapeutics 163 — Gain on contingent consideration from Kamada 553 — Income from discontinued operations $ 1,239 $ 1,013

Cash and Cash Equivalents (Tabl

Cash and Cash Equivalents (Tables)	12 Months Ended
Cash and Cash Equivalents (Tables)	Dec. 31, 2023
Cash and Cash Equivalents [Abstract]
Schedule of Cash and Cash Equivalents	The following table shows our cash and cash equivalents as of December 31, 2023 and 2022: As of December 31, (in thousands) 2023 2022 Cash $ 3,732 $ 1,066 Cash equivalents 13,171 21,569 Total cash and cash equivalents $ 16,904 $ 22,635

Property and Equipment, Net (Ta

Property and Equipment, Net (Tables)	12 Months Ended
Property and Equipment, Net (Tables)	Dec. 31, 2023
Property, Plant and Equipment [Abstract]
Summary of Property and Equipment	Property and equipment consist of the following: For the Year Ended December 31, (in thousands) 2023 2022 Leasehold improvements $ 2,228 $ 2,228 Furniture and equipment 12,260 12,260 Property and equipment, gross 14,488 14,488 Less: Accumulated depreciation ( 13,593 ) ( 13,026 ) Total property and equipment, net $ 895 $ 1,462

Liability Related to Sale of _2

Liability Related to Sale of Royalties (Tables)	12 Months Ended
Liability Related to Sale of Royalties (Tables)	Dec. 31, 2023
Sale Of Royalties Liability Disclosure [Abstract]
Schedule of Changes in the Liability Related to the Sale of Royalties	Due to our Amendment to Royalty Purchase Agreement, we did not have any liability related to sale of royalties as of December 31, 2023. The following table presents the changes in the liability in the prior period related to the sale of royalties under the Royalty Purchase Agreement with HCR (in thousands): For the year ended December 31, 2022 Liability related to sale of royalties, beginning balance $ 31,045 Proceeds from sale of royalties, net of transaction costs — Proceeds from milestone payments, net of transaction costs 9,500 Non-cash interest expense 3,416 RUXIENCE royalties paid by Pfizer to HCR ( 6,779 ) Gain from extinguishment of liability related to sale of royalties ( 37,182 ) Liability related to sale of royalties, ending balance — Current portion of liability related to sale of royalties — Liability related to sale of royalties, non-current $ —

Leases and Contingencies (Table

Leases and Contingencies (Tables)	12 Months Ended
Leases and Contingencies (Tables)	Dec. 31, 2023
Leases [Abstract]
Components of Lease Expense	Components of lease expense: For the year ended For the year ended (in thousands) 2023 2022 Operating lease cost $ 1,187 $ 1,277 Total lease cost $ 1,187 $ 1,277
Summary of Right of Use Assets Acquired Under Operating Leases	Right-of-use assets acquired under operating leases: As of December 31, As of December 31, (in thousands) 2023 2022 Seattle office lease, including amendment 4,881 5,303 Total right-of-use assets $ 4,881 $ 5,303 Lease payments: For the year ended For the year ended (in thousands) 2023 2022 For operating leases $ 1,147 $ 895
Summary of Future Minimum Lease Payments	Future minimum payments as of December 31, 2023 are as follows: (in thousands) 2024 1,376 2025 1,376 2026 1,376 2027 and beyond 4,587 Total future minimum lease payments 8,715 Less: imputed interest ( 2,636 ) Total $ 6,079

Net Income (Loss) per Share (Ta

Net Income (Loss) per Share (Tables)	12 Months Ended
Net Income (Loss) per Share (Tables)	Dec. 31, 2023
Earnings Per Share [Abstract]
Computation of Basic and Diluted Net Income (Loss) per Share	The following table presents the computation of basic and diluted net income (loss) per share (in thousands, except share and per share amounts): For the Year Ended December 31, 2023 2022 Net (loss) income from continuing operations $ ( 18,650 ) $ 7,014 Income from discontinued operations 1,239 1,013 Net (loss) income $ ( 17,411 ) $ 8,027 Basic and diluted net (loss) income per share from continuing operations: Basic $ ( 1.52 ) $ 1.38 Diluted $ ( 1.52 ) $ 1.37 Basic and diluted net income per share from discontinued operations: Basic $ 0.10 $ 0.20 Diluted $ 0.10 $ 0.20 Shares used in calculation Basic 12,234,661 5,100,310 Diluted 12,234,661 5,102,914
Summary of Potentially Dilutive Shares Excluded from Calculation of Net Loss Per Share	The following table represents all potentially dilutive shares: As of December 31, (in thousands, except for per share amounts) 2023 2022 Warrants 30,678 351 Outstanding options to purchase common stock 442 364 Unvested RSUs 279 224

Equity (Tables)

Equity (Tables)	12 Months Ended
Equity (Tables)	Dec. 31, 2023
Equity [Abstract]
Summary of Warrant Activity	Number of Weighted-Average Exercise Price Weighted- Outstanding at December 31, 2022 350,589 $ 18.20 0.25 Issued 44,526,070 0.37 2.89 Exercised ( 14,198,518 ) 0.23 2.61 Outstanding at December 31, 2023 30,678,141 0.46 2.99 Exercisable at December 31, 2023 16,479,623 $ 0.66 2.78 Exercised with shares held in abeyance at December 31, 2023 10,388,866 - -
Assumptions used in Estimating the Incremental Fair Value of the Exchanged Common Warrants under Black-scholes Valuation Model	Aptevo uses Black-Scholes valuation model for estimating the incremental fair value of the exchanged common warrants included in the Inducement Agreement. Set forth below are the assumptions used in valuing the common warrants issued: For the Year Ended December 31, 2023 Expected dividend yield 0.00 % Expected volatility 104.01 % Risk-free interest rate 5.40 % Expected average life of warrants 1.2 - 5 years
Summary of Stock-based Compensation Expense Includes Amortization of Stock Options and Restricted Stock Units Granted	Stock-based compensation expense includes amortization of stock options and RSUs granted to employees and non-employees and has been reported in our consolidated statements of operations as follows: For the Year Ended December 31, (in thousands) 2023 2022 Research and development $ 684 $ 196 General and administrative 1,509 1,606 Total stock-based compensation expense $ 2,193 $ 1,802
Assumptions used in Valuing the Stock Options Granted under Black-Scholes Valuation Model	Aptevo utilizes the Black-Scholes valuation model for estimating the fair value of all stock options granted. Set forth below are the assumptions used in valuing the stock options granted: For the Year Ended December 31, 2023 2022 Expected dividend yield 0.00 % 0.00 % Expected volatility 103.63 % 106.24 % Risk-free interest rate 4.18 % 1.71 % Expected average life of options 5 years 5 years
Summary of Stock Option Activity	The following is a summary of option activity for the year ended December 31, 2023: Number of Weighted- Weighted- Outstanding at December 31, 2022 364,266 $ 15.77 7.39 Granted 103,965 2.11 — Exercised — — — Forfeited ( 26,705 ) 20.81 — Outstanding at December 31, 2023 441,526 12.80 7.37 Exercisable at December 31, 2023 248,346 $ 15.72 6.49 Vested and expected to vest at December 31, 2023 400,482 $ 13.66 7.22
Summary of RSU Activity	The following is a summary of restricted stock activity for the year ended December 31, 2023: Number of Weighted Outstanding at December 31, 2022 223,775 $ 8.47 Granted 168,168 2.09 Vested ( 101,504 ) 8.84 Forfeited ( 11,306 ) 4.60 Outstanding at December 31, 2023 279,133 $ 4.65 Expected to Vest 279,133 $ 4.65

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
Income Taxes (Tables)	Dec. 31, 2023
Income Tax Disclosure [Abstract]
Schedule of Income (Loss) from Continuing Operations Before Income Taxes	The components of income (loss) before income taxes were as follows (in thousands): Year ended December 31, (in thousands) 2023 2022 US $ ( 18,650 ) $ 7,014 Income (loss) from continuing operations before benefit from income taxes $ ( 18,650 ) $ 7,014
Schedule of Tax Effects of Temporary Differences Give Rise to Significant Portions of Deferred Tax Assets and Deferred Tax Liabilities	The tax effects of temporary differences that give rise to significant portions of the deferred tax assets and deferred tax liabilities are presented below: For the Year Ended December 31, (in thousands) 2023 2022 Federal losses carryforward $ 35,322 $ 32,793 Capitalized research expenditures 5,859 3,361 Intangible assets 151 195 Stock-based compensation 963 912 State losses carryforward 3,753 3,799 Other deferred tax assets 380 496 Other tax credits 6,121 4,852 Lease liabilities 1,280 1,371 Property and equipment 415 442 Gain related to sale of future royalties — 2,016 Deferred tax assets, gross 54,244 50,237 Valuation allowance ( 53,217 ) ( 49,113 ) Deferred tax assets, net of valuation 1,027 1,124 ROU assets ( 1,027 ) ( 1,124 ) Deferred tax liability ( 1,027 ) ( 1,124 ) Net deferred tax assets $ — $ —
Schedule of Reconciliation of Federal Statutory Income Tax Rate to Effective Income Tax from Continuing Operations	The reconciliation of the federal statutory income tax rate to the Company’s effective income tax from continuing operations is as follows: Year ended December 31, 2023 2022 Federal tax at statutory rates 21.0 % 21.0 % State taxes, net of federal benefit - 0.2 % - 1.8 % Change in valuation allowance - 23.8 % - 12.5 % Tax credits 5.0 % - 15.3 % Permanent differences - 0.1 % 0.8 % Stock-based compensation - 2.6 % 10.1 % Other 0.7 % - 2.3 % Total income tax benefit 0.0 % 0.0 %

Nature of Business and Signif_4

Nature of Business and Significant Accounting Policies - Additional Information (Details) $ in Thousands			1 Months Ended	12 Months Ended
	Mar. 29, 2023 USD ($)	Feb. 28, 2023 USD ($)	Mar. 31, 2022	Dec. 31, 2023 USD ($) Platform	Dec. 31, 2022 USD ($)
Nature Of Business [Line Items]
Number of technology platforms \| Platform				2
Net income (loss)				$ (17,411)	$ 8,027
Accumulated deficit				(223,447)	(206,036)
Net cash used in operating activities				$ (11,730)	(21,022)
Cash equivalents, maturity period				90 days
Proceeds from sale of investments				$ 47,500
Milestone payment		$ 2,500		$ 12,500
One time payment of royalties					$ 6,779
Stock Option
Nature Of Business [Line Items]
Expected dividend yield				0%	0%
Estimated forfeiture rate				29%	30%
HCR
Nature Of Business [Line Items]
Milestone payment				$ 10,000
R U X I E N C E
Nature Of Business [Line Items]
Royalty revenue			2.50%	2.50%
One time payment of royalties				$ 2,500
Payment Interest Purchase Agreement
Nature Of Business [Line Items]
Repayment of debt	$ 2,800
Exit fees	$ 300
Maximum
Nature Of Business [Line Items]
Cash equivalents, maturity period				90 days
Nasdaq Capital Market
Nature Of Business [Line Items]
Net income (loss)				$ 17,400
Accumulated deficit					$ 223,400
Net cash used in operating activities				$ 11,700

Nature of Business and Signif_5

Nature of Business and Significant Accounting Policies - Schedule of Estimated Useful Lives of Property and Equipment (Details)	Dec. 31, 2023
Furniture and Equipment \| Minimum
Property Plant And Equipment [Line Items]
Estimated useful lives	7 years
Furniture and Equipment \| Maximum
Property Plant And Equipment [Line Items]
Estimated useful lives	10 years
Software and Hardware
Property Plant And Equipment [Line Items]
Property, Plant, and Equipment, Useful Life, Term, Description [Extensible Enumeration]	us-gaap:UsefulLifeShorterOfTermOfLeaseOrAssetUtilityMember
Software and Hardware \| Minimum
Property Plant And Equipment [Line Items]
Estimated useful lives	3 years
Software and Hardware \| Maximum
Property Plant And Equipment [Line Items]
Estimated useful lives	5 years
Leasehold Improvements
Property Plant And Equipment [Line Items]
Property, Plant, and Equipment, Useful Life, Term, Description [Extensible Enumeration]	us-gaap:UsefulLifeShorterOfTermOfLeaseOrAssetUtilityMember

Discontinued Operations - Summa

Discontinued Operations - Summary of Reconciliation of Carrying Amounts of Assets and Liabilities and Income (Loss) from Discontinued Operation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Deferred payments from Medexus	$ 523	$ 1,013
Income from discontinued operations	1,239	$ 1,013
Aptevo BioTherapeutics [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Deferred payments from Medexus	200
Gain on contingent consideration	163
Kamada [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Gain on contingent consideration	$ 553

Discontinued Operations - Addit

Discontinued Operations - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Deferred payment	$ 523	$ 1,013
IXINITY
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Deferred payment	500	$ 1,000
Aptevo BioTherapeutics
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Deferred payment	200
Hyperimmune Business
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Deferred payment	$ 600

XOMA Transaction - Additional I

XOMA Transaction - Additional Information (Details) - USD ($) $ in Thousands		12 Months Ended
	Mar. 29, 2023	Dec. 31, 2023	Dec. 31, 2022
Related Party Transaction [Line Items]
Income from discontinued operations		$ 1,239	$ 1,013
Payment Interest Purchase Agreement
Related Party Transaction [Line Items]
Income from discontinued operations	$ 9,600
Additional post-closing payment	$ 50
Percentage of entitlement to receive deferred payments	100%
Percentage of entitlement to receive Canadian approval milestone payment	25%
Percentage of entitlement to receive European approval milestone payment	50%
Payment Interest Purchase Agreement \| ASC 610-20
Related Party Transaction [Line Items]
Income from discontinued operations		9,600
Additional post-closing payment		$ 50

Collaboration Agreements - Addi

Collaboration Agreements - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Research and development expense	$ 2.7	$ 1.7
Percentage of cost related to research and development	50%	50%

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Details) - USD ($)	Dec. 31, 2023	Dec. 31, 2022
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Money market funds	$ 13,200,000	$ 21,600,000
Level Two
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value assets	0	0
Fair value liabilities	0	0
Level Three
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value assets	0	0
Fair value liabilities	$ 0	$ 0

Cash and Cash Equivalents - Add

Cash and Cash Equivalents - Additional Information (Details)	12 Months Ended
	Dec. 31, 2023
Restricted Cash And Cash Equivalents Items [Line Items]
Cash equivalents, maturity period	90 days

Cash and Cash Equivalents - Sch

Cash and Cash Equivalents - Schedule of Cash and Cash Equivalents (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Cash and Cash Equivalents [Abstract]
Cash	$ 3,732	$ 1,066
Cash equivalents	13,171	21,569
Total cash and cash equivalents	$ 16,904	$ 22,635

Property and Equipment, Net - S

Property and Equipment, Net - Summary of Property and Equipment (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 14,488	$ 14,488
Less: Accumulated depreciation	(13,593)	(13,026)
Total property and equipment, net	895	1,462
Leasehold Improvements
Property Plant And Equipment [Line Items]
Property and equipment, gross	2,228	2,228
Furniture and Equipment
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 12,260	$ 12,260

Property and Equipment, Net - A

Property and Equipment, Net - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Property, Plant and Equipment [Abstract]
Depreciation expense	$ 0.6	$ 0.9

Debt - Additional Information (

Debt - Additional Information (Details) - USD ($)	Mar. 29, 2023	Dec. 31, 2023	Aug. 05, 2020
Line Of Credit Facility [Line Items]
Maximum borrowing capacity			$ 25,000,000
Debt outstanding		$ 0
Payment Interest Purchase Agreement
Line Of Credit Facility [Line Items]
Repayment of debt	$ 2,800,000
Exit fees	$ 300,000
Credit Agreement
Line Of Credit Facility [Line Items]
Line of credit facility, used borrowing capacity			$ 25,000,000

Debt - Schedule of Future Princ

Debt - Schedule of Future Principal, Interest, and Other Related Fee Payments in Connection with the Credit Agreement (Details)	Dec. 31, 2023 USD ($)
Debt Disclosure [Abstract]
Total	$ 0

Liability Related to Sale of _3

Liability Related to Sale of Royalties - Additional Information (Details) - USD ($) $ in Thousands			1 Months Ended	12 Months Ended
	Feb. 28, 2023	Jun. 07, 2022	Dec. 31, 2023	Dec. 31, 2023	Dec. 31, 2022
Debt Instrument [Line Items]
Proceeds from sale of investments				$ 47,500
Closing payments			$ 35,000
Milestone payment	$ 2,500			12,500
Gain from extinguishment of liability related to sale of royalties		$ 37,200			$ 37,182
HCR
Debt Instrument [Line Items]
Milestone payment				10,000
Transaction costs			$ 1,100	1,100
HCR \| Liability
Debt Instrument [Line Items]
Proceeds from royalties received				$ 35,000

Liability Related to Sale of _4

Liability Related to Sale of Royalties - Schedule of Changes in the Liability Related to the Sale of Royalties (Details) - USD ($) $ in Thousands		12 Months Ended
	Jun. 07, 2022	Dec. 31, 2022
Debt Disclosure [Abstract]
Liability related to sale of royalties, beginning balance		$ 31,045
Proceeds from milestone payments, net of transaction costs		9,500
Non-cash interest expense		3,416
RUXIENCE royalties paid by Pfizer to HCR		(6,779)
Gain from extinguishment of liability related to sale of royalties	$ (37,200)	$ (37,182)

Leases and Contingencies - Addi

Leases and Contingencies - Additional Information (Details) $ in Thousands	1 Months Ended	12 Months Ended
	Mar. 31, 2019 RenewalOption	Dec. 31, 2023 USD ($) Equipment	Dec. 31, 2022 USD ($)	May 26, 2022 USD ($)
Lessee Lease Description [Line Items]
Operating lease number of piece for lab equipment \| Equipment		0
Operating lease right-of-use asset		$ 4,881	$ 5,303	$ 4,400
Operating lease liability		$ 6,079
Financing lease number of equipment \| Equipment		0
Long term portion of operating lease liabilities		$ 5,397	6,079
Current portion of operating lease liabilities		$ 700	$ 400
Operating Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration]		Other Liabilities, Current	Other Liabilities, Current
Weighted average remaining lease term for operating leases		6 years 3 months 18 days	7 years 3 months 18 days
Weighted discount rate for operating leases		12.03%	12.03%
Office Space Lease
Lessee Lease Description [Line Items]
Initial operating lease term date	2030-04
Operating lease renewal option description	the term through April 2030 and provide two options to extend the lease term, each by five years, as well as a one-time option to terminate the lease in April 2023
Operating lease renewal option term	5 years
Number of operating lease renewal option \| RenewalOption	2
Operating lease option to extend	true
Variable expense		$ 800	$ 700

Leases and Contingencies - Comp

Leases and Contingencies - Components of Lease Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Leases [Abstract]
Operating lease cost	$ 1,187	$ 1,277
Total lease cost	$ 1,187	$ 1,277

Leases and Contingencies - Summ

Leases and Contingencies - Summary of Right of Use Assets Acquired Under Operating Leases (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	May 26, 2022
Lessee Lease Description [Line Items]
Total right-of-use assets	$ 4,881	$ 5,303	$ 4,400
For operating leases	1,147	895
Seattle Office Lease, Including Amendment
Lessee Lease Description [Line Items]
Total right-of-use assets	$ 4,881	$ 5,303

Leases and Contingencies - Su_2

Leases and Contingencies - Summary of Future Minimum Lease Payments (Details) $ in Thousands	Dec. 31, 2023 USD ($)
Leases [Abstract]
2024	$ 1,376
2025	1,376
2026	1,376
2027 and beyond	4,587
Total future minimum lease payments	8,715
Less: imputed interest	(2,636)
Total	$ 6,079

Net Income (Loss) Per Share - C

Net Income (Loss) Per Share - Computation of Basic and Diluted Net Income (Loss) per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Earnings Per Share [Abstract]
Net (loss) income from continuing operations	$ (18,650)	$ 7,014
Income from discontinued operations	1,239	1,013
Net (loss) income	$ (17,411)	$ 8,027
Basic and diluted net (loss) income per share from continuing operations:
Basic	$ (1.52)	$ 1.38
Diluted net income (loss) per share from continuing operations:
Diluted	(1.52)	1.37
Basic net income per share from discontinued operations:
Basic	0.1	0.2
Diluted net income per share from discontinued operations:
Diluted	$ 0.1	$ 0.2
Basic shares used in calculation:
Basic	12,234,661	5,100,310
Diluted shares used in calculation:
Diluted	12,234,661	5,102,914

Net Income (Loss) Per Share - S

Net Income (Loss) Per Share - Summary of Potentially Dilutive Shares Excluded from Calculation of Net Loss Per Share (Details) - shares shares in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Warrants
Schedule Of Earnings Per Share Basic And Diluted [Line Items]
Anti-dilutive shares excluded from calculation of diluted net loss per share	30,678	351
Outstanding Options to Purchase Common Stock
Schedule Of Earnings Per Share Basic And Diluted [Line Items]
Anti-dilutive shares excluded from calculation of diluted net loss per share	442	364
Unvested RSUs
Schedule Of Earnings Per Share Basic And Diluted [Line Items]
Anti-dilutive shares excluded from calculation of diluted net loss per share	279	224

Equity - Additional Information

Equity - Additional Information (Details) - USD ($)						1 Months Ended	3 Months Ended	12 Months Ended
Equity - Additional Information (Details) - USD ($)	Nov. 09, 2023	Aug. 04, 2023	Feb. 16, 2022	Dec. 14, 2020	Nov. 08, 2020	Mar. 31, 2019	Dec. 31, 2023	Dec. 31, 2023	Dec. 31, 2022
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Warrants outstanding							30,678,141	30,678,141	350,589
Total issuance costs								$ 2,300,000
Warrant modification - incremental value								2,080,000
Issuance of common stock, net								$ 6,428,000	$ 6,934,000
Preferred stock, par value							$ 0.001	$ 0.001	$ 0.001
Common stock, par value							0.001	$ 0.001	$ 0.001
Pre funded warrants outstanding, term						10 years
Pre funded warrants expire date						Mar. 11, 2029
Tranche Two
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of common stock to be issued exercise of prefunded warrants						153,571
Pre funded warrants exercise price, per share						$ 0.14
Broadridge Corporate Issuer Solutions
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Preferred share purchase right					1
Broadridge Corporate Issuer Solutions \| Series A Junior Participating Preferred Stock [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Warrants exercise price, per share					$ 2.02
Preferred stock, par value					$ 0.001
Share portion entitled to purchase by rights					When exercisable, each Right initially would represent the right to purchase from the Company one one-thousandth of a share of a newly-designated series of preferred stock
Percentage of beneficial ownership					10%
Purchase Agreement \| Lincoln Park
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Proceeds from issuance of common stock								$ 500,000
Equity Distribution Agreement
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Proceeds from issuance of common stock								$ 1,600,000	$ 7,000,000
Common stock price per share							2.26	$ 2.26	$ 4.92
Common stock, par value				$ 0.001
Series A and Series B Common Warrants \| Warrant Inducement Agreement
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Warrants exercise price, per share	$ 0.233						$ 0.233	$ 0.233
Number of warrants issued	28,397,036
Percentage of number of common stock issued upon exercise of warrants	200%
Series A Common Warrants \| Warrant Inducement Agreement
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Warrants exercise price, per share	$ 0.233
Number of warrants issued	12,384,002
Series A-1 Common Warrants \| Warrant Inducement Agreement
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of common stock to be issued up conversion of warrants	6,192,001
Warrants outstanding, term	4 years 8 months
Warrants outstanding							6,192,001	6,192,001
Series A-2 Common Warrants \| Warrant Inducement Agreement
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of common stock to be issued up conversion of warrants	6,192,001
Warrants outstanding, term	5 years
Warrants outstanding							6,192,001	6,192,001
Warrants exercisable date								Feb. 05, 2024
Series B Common Warrants \| Warrant Inducement Agreement
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Warrants exercise price, per share	$ 0.233
Number of warrants issued	16,013,034
Series B-1 Common Warrants \| Warrant Inducement Agreement
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of common stock to be issued up conversion of warrants	8,006,517
Warrants outstanding, term	14 months
Warrants outstanding							8,006,517	8,006,517
Series B-2 Common Warrants \| Warrant Inducement Agreement
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of common stock to be issued up conversion of warrants	8,006,517
Warrants outstanding, term	24 months
Warrants outstanding							8,006,517	8,006,517
Warrants exercisable date								Feb. 05, 2024
New Warrants \| Warrant Inducement Agreement
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Additional amount to be received upon exercise of warrants								$ 6,600,000
Public Offering
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Proceeds from issuance of common stock		$ 4,300,000
Issuance of common stock shares		2,221,550
Common stock price per share		$ 0.62
Public Offering \| Pre-funded Warrants
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of common stock to be issued up conversion of warrants		5,842,967
Warrants exercise price, per share		$ 0.001
Common stock price per share		$ 0.62
Public Offering \| Series A and Series B Common Warrants
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of common stock to be issued up conversion of warrants		16,129,034
Warrants exercise price, per share		$ 0.62
Warrants
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of common stock to be issued up conversion of warrants							3,809,652	3,809,652
Warrants outstanding, term						5 years
Warrants outstanding							350,589	350,589	350,589
Warrants expiration date							Mar. 31, 2024	Mar. 31, 2024
Number of shares held in abeyance and reserved for issuance							10,388,866	10,388,866
Common stock issued upon exercise of stock options								0	0
Warrants \| Tranche One
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Warrants exercise price, per share						$ 18.2
Number of warrants issued						1,571,429
Warrants \| Series A
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Warrants exercise price, per share							$ 0.62	$ 0.62
Warrants outstanding							1,872,516	1,872,516
Number of warrants to be expired		1,872,516
Warrants expiration date		Aug. 04, 2028
Warrants \| Series B
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Warrants exercise price, per share							$ 0.62	$ 0.62
Warrants outstanding							58,000	58,000
Number of warrants to be expired		58,000
Warrants expiration date		Feb. 04, 2025
Warrants \| Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of common stock to be issued up conversion of warrants						1,725,000
Warrants \| Warrant Inducement Agreement
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Gross proceeds from warrant exercises	$ 3,300,000
Total issuance costs	2,300,000
Banker and legal fees	200,000
Non-cash warrant modification costs	2,100,000
Warrant modification - incremental value	$ 2,100,000
Warrants \| Warrant Inducement Agreement \| Series A
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Warrants outstanding	6,192,001
Common stock issued upon exercise of stock options							14,198,518
Warrants \| Warrant Inducement Agreement \| Series B
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Warrants outstanding	8,006,517
Common stock issued upon exercise of stock options							14,198,518
Common Stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Issuance of common stock, net								$ 9,000	$ 1,000
Issuance of common stock shares								9,095,430	1,452,065
Common Stock \| Purchase Agreement \| Lincoln Park
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares of common stock issued for cash consideration								300,000	0
Issuance of common stock shares			99,276						99,276
Cash consideration as an initial fee for commitment to purchase shares of common stock			$ 0
Common Stock \| Purchase Agreement \| Minimum \| Lincoln Park
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Minimum prevailing market price to direct purchase			$ 1
Common Stock \| Purchase Agreement \| Maximum \| Lincoln Park
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Issuance of common stock, net			$ 35,000,000
Common Stock \| Equity Distribution Agreement
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Issuance of common stock shares								730,913	1,452,065
Common Stock \| Equity Distribution Agreement \| Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Aggregate offering price				$ 50,000,000
Common Stock \| Series A Common Warrants \| Warrant Inducement Agreement \| Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of common stock to be issued up conversion of warrants	12,384,002
Common Stock \| Series B Common Warrants \| Warrant Inducement Agreement \| Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of common stock to be issued up conversion of warrants	16,013,034

Equity - Additional Informati_2

Equity - Additional Information (Details1) - USD ($) $ / shares in Units, $ in Millions		12 Months Ended
	Jun. 01, 2018	Dec. 31, 2023	Dec. 31, 2022	Jun. 07, 2022
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Weighted-average grant date fair value per share of options granted		$ 1.68	$ 4.36
Aggregate intrinsic value of options exercised		$ 0	$ 0
Total fair value of stock option vested		1.2	1.3
Unvested RSUs
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Unrecognized compensation expense		$ 0.8	$ 1.5
Options expected to vest, weighted average period		1 year 2 months 12 days	1 year 7 months 6 days
Stock Option
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Estimated forfeiture rate		29%	30%
Unrecognized compensation expense		$ 0.8
Options expected to vest, weighted average remaining vesting term		8 months 12 days
Stock Option \| Minimum
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Expected volatility		$ 0.17	$ 2
Stock Option \| Maximum
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Expected volatility		$ 2.54	$ 8.42
2018 Stock Incentive Plan \| Unvested RSUs
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Stock authorized for issuance under Stock Plan	300,000			500,000
Maximum number of returning shares from old plan to be add to shares reserve	300,000
Number of shares available for grant		100,000
Stock plan termination period	10 years
2018 Stock Incentive Plan \| Unvested RSUs \| Non-employee Directors
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Stock plan vesting period	1 year
2018 Stock Incentive Plan \| Unvested RSUs \| Minimum
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Stock plan vesting period	1 year
2018 Stock Incentive Plan \| Unvested RSUs \| Maximum
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Stock plan vesting period	3 years

Equity - Summary of Warrant Act

Equity - Summary of Warrant Activity (Details) - $ / shares	12 Months Ended
Equity - Summary of Warrant Activity (Details) - $ / shares	Dec. 31, 2023	Dec. 31, 2022
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of Shares, Outstanding, Beginning Balance	350,589
Number of Shares, Issued	44,526,070
Number of Shares, Exercised	(14,198,518)
Number of Shares, Outstanding, Ending Balance	30,678,141	350,589
Number of Shares, Exercisable	16,479,623
Number of Shares, Exercised with shares held in abeyance	10,388,866
Weighted-Average Exercise Price, Outstanding, Beginning Balance	$ 18.2
Weighted-Average Exercise Price, Issued	0.37
Weighted-Average Exercise Price, Exercised	0.23
Weighted-Average Exercise Price, Outstanding, Ending Balance	0.46	$ 18.2
Weighted-Average Exercise Price, Exercisable	$ 0.66
Weighted-Average Remaining Term, Outstanding	2 years 11 months 26 days	3 months
Weighted-Average Remaining Term, Issued	2 years 10 months 20 days
Weighted-Average Remaining Term, Exercised	2 years 7 months 9 days
Weighted-Average Remaining Term, Exercisable	2 years 9 months 10 days

Equity - Assumptions used in Es

Equity - Assumptions used in Estimating the Incremental Fair Value of the Exchanged Common Warrants under Black-scholes Valuation Model (Details)	12 Months Ended
	Dec. 31, 2023
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected dividend yield	0%
Expected volatility	104.01%
Risk-free interest rate	5.40%
Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected average life of warrants	1 year 2 months 12 days
Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected average life of warrants	5 years

Equity - Summary of Stock-based

Equity - Summary of Stock-based Compensation Expense Includes Amortization of Stock Options and Restricted Stock Units Granted (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense	$ 2,193	$ 1,802
Research and Development
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense	684	196
General and Administrative
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense	$ 1,509	$ 1,606

Equity - Assumptions used in Va

Equity - Assumptions used in Valuing the Stock Options Granted under Black-Scholes Valuation Model (Details) - Stock Option	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected dividend yield	0%	0%
Expected volatility	103.63%	106.24%
Risk-free interest rate	4.18%	1.71%
Expected average life of options	5 years	5 years

Equity - Summary of Stock Optio

Equity - Summary of Stock Option Activity (Details) - Stock Option	12 Months Ended
	Dec. 31, 2023 $ / shares shares	Dec. 31, 2022 $ / shares shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of Shares, Outstanding, Beginning balance \| shares	364,266
Number of Shares, Granted \| shares	103,965
Number of Shares, Forfeited \| shares	(26,705)
Number of Shares, Outstanding, Ending balance \| shares	441,526	364,266
Number of Shares, Exercisable \| shares	248,346
Number of Shares, Vest and expected to Vest \| shares	400,482
Weighted-Average Exercise Price, Outstanding, Beginning balance \| $ / shares	$ 15.77
Weighted-Average Exercise Price, Granted \| $ / shares	2.11
Weighted-Average Exercise Price, Forfeited \| $ / shares	20.81
Weighted-Average Exercise Price, Outstanding, Ending balance \| $ / shares	12.8	$ 15.77
Weighted-Average Exercise Price, Exercisable \| $ / shares	15.72
Weighted-Average Exercise Price, vest and expected to vest \| $ / shares	$ 13.66
Weighted-Average Remaining Term, Outstanding	7 years 4 months 13 days	7 years 4 months 20 days
Weighted-Average Remaining Term, Exercisable	6 years 5 months 26 days
Weighted-Average Remaining Term, Vested and expected to vest	7 years 2 months 19 days

Equity - Summary of Restricted

Equity - Summary of Restricted Stock Activity (Details) - Unvested RSUs	12 Months Ended
	Dec. 31, 2023 $ / shares shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of Units, Outstanding, Beginning balance \| shares	223,775
Number of Units, Granted \| shares	168,168
Number of Units, Vested \| shares	(101,504)
Number of Units, Forfeited \| shares	(11,306)
Number of Units, Outstanding, Ending balance \| shares	279,133
Number of Units, Expected to Vest \| shares	279,133
Weighted Average Fair Value per Unit, Outstanding Beginning Balance \| $ / shares	$ 8.47
Weighted Average Fair Value per Unit, Granted \| $ / shares	2.09
Weighted Average Fair Value per Unit, Vested \| $ / shares	8.84
Weighted Average Fair Value per Unit, Forfeited \| $ / shares	4.6
Weighted Average Fair Value per Unit, Outstanding Ending Balance \| $ / shares	4.65
Weighted Average Fair Value per Unit, Expected to Vest \| $ / shares	$ 4.65

401(K) Savings Plan - Additiona

401(K) Savings Plan - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Defined Contribution Plan Disclosure [Line Items]
Maximum employee deferral rate	6%
Matching contributions made by employer	$ 0.2	$ 0.2
Maximum
Defined Contribution Plan Disclosure [Line Items]
Employer matching contribution, qualified deferral percentage	50%

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) - USD ($)	12 Months Ended
Income Taxes - Additional Information (Details) - USD ($)	Dec. 31, 2023	Dec. 31, 2022
Income Taxes [Line Items]
Income tax expense (benefit)	$ 0	$ 0
Increase in valuation allowance	4,200,000
Net operating loss carryforwards	153,000,000
Uncertain income tax positions	0
Federal
Income Taxes [Line Items]
Net operating loss carryforwards	168,200,000	156,200,000
Amount of operating loss due to expire	15,200,000
State
Income Taxes [Line Items]
Net operating loss carryforwards	70,500,000	71,100,000
Tax credit carryforwards	$ 6,100,000	$ 4,900,000
Earliest Tax Year \| Federal
Income Taxes [Line Items]
Operating losses, begin to expiration year	2037
Tax credits, begin to expiration year	2037

Income Taxes - Schedule of Inco

Income Taxes - Schedule of Income (Loss) from Continuing Operations Before Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Income Tax Disclosure [Abstract]
US	$ (18,650)	$ 7,014
Income (loss) from continuing operations before benefit from income taxes	$ (18,650)	$ 7,014

Income Taxes - Schedule of Tax

Income Taxes - Schedule of Tax Effects of Temporary Differences Give Rise to Significant Portions of Deferred Tax Assets and Deferred Tax Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Income Tax Disclosure [Abstract]
Federal losses carryforward	$ 35,322	$ 32,793
Capitalized research expenditures	5,859	3,361
Intangible assets	151	195
Stock-based compensation	963	912
State losses carryforward	3,753	3,799
Other deferred tax assets	380	496
Other tax credits	6,121	4,852
Lease liabilities	1,280	1,371
Property and equipment	415	442
Gain related to sale of future royalties		2,016
Deferred tax assets, gross	54,244	50,237
Valuation allowance	(53,217)	(49,113)
Deferred tax assets, net of valuation	1,027	1,124
ROU assets	(1,027)	(1,124)
Deferred tax liability	$ (1,027)	$ (1,124)

Income Taxes - Schedule of Reco

Income Taxes - Schedule of Reconciliation of Federal Statutory Income Tax Rate to Effective Income Tax from Continuing Operations (Details)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Income Tax Disclosure [Abstract]
Federal tax at statutory rates	21%	21%
State taxes, net of federal benefit	(0.20%)	(1.80%)
Change in valuation allowance	(23.80%)	(12.50%)
Tax credits	5%	(15.30%)
Permanent differences	(0.10%)	0.80%
Stock-based compensation	(2.60%)	10.10%
Other	0.70%	(2.30%)
Total income tax benefit	0%	0%

Subsequent Events - Additional

Subsequent Events - Additional Information (Details)	Mar. 04, 2024 shares	Feb. 15, 2024 shares	Feb. 05, 2024 $ / shares	Jan. 02, 2024 shares	Feb. 29, 2024 shares	Dec. 31, 2023 $ / shares shares	Dec. 31, 2022 $ / shares shares
Subsequent Event [Line Items]
Common stock issued						19,468,180	6,466,294
Common stock outstanding						19,468,180	6,466,294
Common stock par value \| $ / shares						$ 0.001	$ 0.001
Subsequent Event
Subsequent Event [Line Items]
Shares remained abeyance		6,393,996
Common stock issued					23,472,436
Common stock outstanding					23,472,436
Minimum percentage of common stock outstanding			19.99%
Common stock par value \| $ / shares			$ 0.001
Subsequent Event \| August 2023 Common Warrants
Subsequent Event [Line Items]
Shares released from abeyance	1,130,000	1,130,000		2,864,870
Subsequent Event \| Minimum
Subsequent Event [Line Items]
Reverse stock split			0.02
Subsequent Event \| Maximum
Subsequent Event [Line Items]
Reverse stock split			0.06