Aptevo Therapeutics (APVO) 10-Q 12 Nov 21 2021 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2021	Nov. 11, 2021
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2021
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q3
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 Small Business	true
Entity Emerging Growth Company	true
Entity Extended Transition Period	true
Entity Shell Company	false
Document Transition Report	false
Document Quarterly Report	true
Entity Interactive Data Current	Yes
Entity Common Stock, Shares Outstanding		4,898,034
Title of 12(b) Security	Common Stock, $0.001 par value per share
Security Exchange Name	NASDAQ
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
Entity Incorporation, State or Country Code	DE
Entity Current Reporting Status	Yes
Entity Tax Identification Number	81-1567056
Entity File Number	001-37746

CONDENSED CONSOLIDATED BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 52,118	$ 39,979
Restricted cash - current	1,259	2,555
Royalty receivable	3,096	2,369
Prepaid expenses	2,391	2,228
Other current assets	9	133
Total current assets	58,873	47,264
Property and equipment, net	2,521	2,815
Operating lease right-of-use asset	1,865	2,722
Other assets	746	746
Total assets	64,005	53,547
Current liabilities:
Accounts payable and other accrued liabilities	3,687	5,583
Accrued compensation	1,565	2,757
Liability related to the sale of future royalties, net - short-term	13,369
Current portion of long-term debt	11,167	5,000
Other current liabilities	2,592	1,199
Total current liabilities	32,380	14,539
Liability related to the sale of future royalties, net - long-term	18,711
Loan payable - long-term	4,012	20,054
Operating lease liability	1,610	2,360
Total liabilities	56,713	36,953
Stockholders' equity:
Preferred stock: $0.001 par value; 15,000,000 shares authorized, zero shares issued or outstanding
Common stock: $0.001 par value; 500,000,000 shares authorized; 4,895,759 and 4,410,909 shares issued and outstanding at September 30, 2021 and December 31, 2020, respectively	47	46
Additional paid-in capital	215,036	202,154
Accumulated deficit	(207,791)	(185,606)
Total stockholders' equity	7,292	16,594
Total liabilities and stockholders' equity	$ 64,005	$ 53,547

CONDENSED CONSOLIDATED BALANC_2

CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) (Parenthetical) - $ / shares	Sep. 30, 2021	Dec. 31, 2020
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	4,895,759	4,410,909
Common stock, shares outstanding	4,895,759	4,410,909

CONDENSED CONSOLIDATED STATEMEN

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Income Statement [Abstract]
Royalty revenue	$ 3,096	$ 1,463	$ 8,627	$ 1,936
Revenue from Contract with Customer, Product and Service [Extensible List]	us-gaap:RoyaltyMember	us-gaap:RoyaltyMember	us-gaap:RoyaltyMember	us-gaap:RoyaltyMember
Operating expenses:
Research and development	$ (4,367)	$ (4,494)	$ (14,451)	$ (12,940)
General and administrative	(3,479)	(3,215)	(11,536)	(9,671)
Loss from operations	(4,750)	(6,246)	(17,360)	(20,675)
Other expense:
Other expense from continuing operations, net	(2,327)	(702)	(5,451)	(973)
Loss on extinguishment of debt				(2,104)
Net loss from continuing operations	(7,077)	(6,948)	(22,811)	(23,752)
Discontinued operations:
Income from discontinued operations	80	157	626	13,055
Net loss	$ (6,997)	$ (6,791)	$ (22,185)	$ (10,697)
Net loss from continuing operations per share	$ (1.45)	$ (2.15)	$ (4.94)	$ (7.35)
Net income from discontinued operations per share	0.02	0.05	0.14	4.04
Basic and diluted net loss per basic share	$ (1.43)	$ (2.10)	$ (4.80)	$ (3.31)
Weighted-average shares used to compute per share calculations	4,891,881	3,232,811	4,617,357	3,233,257

CONDENSED CONSOLIDATED STATEM_2

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Operating Activities
Net loss	$ (22,185)	$ (10,697)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation	1,465	1,057
Depreciation and amortization	884	1,064
Loss on disposal of property and equipment	4
Gain on sale of Aptevo BioTherapeutics		(14,338)
Loss on extinguishment of debt		2,104
Non-cash interest expense and other	4,387	606
Changes in operating assets and liabilities:
Royalty receivable	(727)	(1,463)
Prepaid expenses and other current assets	(39)	(455)
Operating lease right-of-use asset	857	757
Accounts payable, accrued compensation and other liabilities	(1,695)	(2,824)
Long-term operating lease liability	(750)	(725)
Changes in assets and liabilities held for sale		1,719
Net cash used in operating activities	(17,799)	(23,195)
Investing Activities
Cash received from sale of Aptevo BioTherapeutics		28,120
Purchases of property and equipment	(595)
Net cash (used in) provided by investing activities	(595)	28,120
Financing Activities
Proceeds from other long-term obligations, net of issuance costs		24,730
Payments of long-term debt, including exit and other fees	(10,550)	(22,104)
Repayments under liability related to sale of future royalties	(5,531)
Proceeds from sale of future royalties	35,000
Transaction costs from sale of future royalties	(1,100)
Proceeds from exercise of stock options	200
Proceeds from exercise of warrants	985
Proceeds from common stock issued pursuant to the Lincoln Park Purchase Agreement	10,233
Net cash provided by financing activities	29,237	2,626
Increase in cash, cash equivalents, and restricted cash	10,843	7,551
Cash, cash equivalents, and restricted cash at beginning of period	42,534	19,946
Cash, cash equivalents, and restricted cash at end of period	$ 53,377	$ 27,497

CONDENSED CONSOLIDATED STATEM_3

CONDENSED CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY (Unaudited) - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Accumulated Deficit
Balance at Dec. 31, 2019	$ 11,842	$ 45	$ 179,653	$ (167,856)
Balance (in shares) at Dec. 31, 2019		3,234,231
Cancellation of fractional shares arising from reverse stock split		(1,420)
Stock-based compensation	413		413
Net income (loss) for the period	2,897			2,897
Balance at Mar. 31, 2020	15,152	$ 45	180,066	(164,959)
Balance (in shares) at Mar. 31, 2020		3,232,811
Balance at Dec. 31, 2019	11,842	$ 45	179,653	(167,856)
Balance (in shares) at Dec. 31, 2019		3,234,231
Net income (loss) for the period	(10,697)
Balance at Sep. 30, 2020	2,202	$ 45	180,710	(178,553)
Balance (in shares) at Sep. 30, 2020		3,232,811
Balance at Mar. 31, 2020	15,152	$ 45	180,066	(164,959)
Balance (in shares) at Mar. 31, 2020		3,232,811
Stock-based compensation	301		301
Net income (loss) for the period	(6,803)			(6,803)
Balance at Jun. 30, 2020	8,650	$ 45	180,367	(171,762)
Balance (in shares) at Jun. 30, 2020		3,232,811
Stock-based compensation	343		343
Net income (loss) for the period	(6,791)			(6,791)
Balance at Sep. 30, 2020	2,202	$ 45	180,710	(178,553)
Balance (in shares) at Sep. 30, 2020		3,232,811
Balance at Dec. 31, 2020	16,594	$ 46	202,154	(185,606)
Balance (in shares) at Dec. 31, 2020		4,410,909
Proceeds from exercise of stock options	86		86
Proceeds from exercise of stock options (in shares)		10,685
Proceeds from exercise of warrants	506		506
Proceeds from exercise of warrants (in shares)		27,828
Stock-based compensation	574		574
Net income (loss) for the period	(7,256)			(7,256)
Balance at Mar. 31, 2021	10,504	$ 46	203,320	(192,862)
Balance (in shares) at Mar. 31, 2021		4,449,422
Balance at Dec. 31, 2020	$ 16,594	$ 46	202,154	(185,606)
Balance (in shares) at Dec. 31, 2020		4,410,909
Common stock sold pursuant to the Lincoln Park Purchase Agreement (in shares)	24.8
Net income (loss) for the period	$ (22,185)
Balance at Sep. 30, 2021	7,292	$ 47	215,036	(207,791)
Balance (in shares) at Sep. 30, 2021		4,895,759
Balance at Mar. 31, 2021	10,504	$ 46	203,320	(192,862)
Balance (in shares) at Mar. 31, 2021		4,449,422
Proceeds from exercise of stock options	25		25
Proceeds from exercise of stock options (in shares)		1,769
Proceeds from exercise of warrants	478		478
Proceeds from exercise of warrants (in shares)		26,277
Common stock sold pursuant to the Lincoln Park Purchase Agreement	10,234	$ 1	10,233
Common stock sold pursuant to the Lincoln Park Purchase Agreement (in shares)		407,047
Stock-based compensation	572		572
Net income (loss) for the period	(7,932)			(7,932)
Balance at Jun. 30, 2021	13,881	$ 47	214,628	(200,794)
Balance (in shares) at Jun. 30, 2021		4,884,515
Proceeds from exercise of stock options	89		89
Proceeds from exercise of stock options (in shares)		11,244
Stock-based compensation	319		319
Net income (loss) for the period	(6,997)			(6,997)
Balance at Sep. 30, 2021	$ 7,292	$ 47	$ 215,036	$ (207,791)
Balance (in shares) at Sep. 30, 2021		4,895,759

Nature of Business and Signific

Nature of Business and Significant Accounting Policies	9 Months Ended
	Sep. 30, 2021
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 immunotherapeutic candidates for the treatment of different forms of cancer. We have developed two versatile and enabling platform technologies for rational design of precision immune stimulatory drugs. Our lead clinical candidate, APVO436, and preclinical candidates, ALG.APV-527 and APVO603, 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 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 three and nine months ended September 30, 2021, we had a net loss of $7.0 million and $22.2 million, respectively. We had an accumulated deficit of $207.8 million as of September 30, 2021. For the nine months ended September 30, 2021, net cash used in our operating activities was $17.8 million. We have suffered recurring losses from operations and negative cash flows from operating activities. We believe that our existing cash resources, the cash to be generated from future deferred payments and milestones, and release of restricted cash securing letters of credit, will be sufficient to meet our projected operating requirements and debt service for at least twelve months from the date of issuance of these financial statements. 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) potential decreases in our expected milestone and deferred payments from Medexus Pharmaceuticals Inc. (Medexus) with respect to IXINITY; (e) whether and to what extent future proceeds are received under our Royalty Purchase Agreement; Basis of Presentation The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles (GAAP). These unaudited condensed consolidated financial statements include all adjustments, which include normal recurring adjustments, necessary for the fair presentation of the Company’s financial position. These unaudited interim consolidated financial statements should be read in conjunction with the audited consolidated financial statements as of and for the year ended December 31, 2020, and the notes thereto, which are included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2020. 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 unaudited condensed consolidated financial statements include the accounts of the Company and our wholly owned subsidiaries: Aptevo Research and Development LLC and Aptevo BioTherapeutics LLC (for the period prior to its sale on February 28, 2020) In March 2020, we effected a 1-for-14 reverse stock split (the “Reverse Split”) of our common stock pursuant to which every 14 shares of our common stock issued and outstanding as of March 26, 2020 were automatically combined into one issued and outstanding share of common stock. No fractional shares were issued as a result of the reverse stock split. Stockholders of record who would otherwise have been entitled to receive a fractional share received a cash payment in lieu thereof. All share and per share information with respect to our common stock have been restated to reflect the effect of the Reverse Split for all periods presented. 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 unaudited condensed consolidated financial statements and accompanying notes. Estimates are used for, but not limited to, forecasted royalties, effective interest rates, clinical accruals, useful lives of equipment, commitments and contingencies, and stock-based compensation forfeiture rates. Given the global economic climate and additional or unforeseen effects from the ongoing COVID-19 pandemic, these estimates are becoming more challenging, and actual results could differ materially from those estimates. Significant Accounting Policies Liability Related to Sale of Future Royalties and Non-Cash Interest Expense On March 30, 2021, the Company entered into and closed a royalty purchase agreement (the Royalty Purchase Agreement) with an entity managed by HealthCare Royalty Management, LLC (HCR) the Company is eligible to receive additional payments in aggregate of up to an additional $32.5 million based on the achievement of sales milestones in 2021, 2022, and 2023 (collectively, the Milestone Amounts) We treat the Royalty Purchase Agreement with HCR (see Note 7) as a debt financing, amortized under the effective interest rate method over the estimated life of the related expected royalty stream. The liabilities related to the sale of future royalties and the debt amortization are based on our current estimates of future royalties expected to be paid over the life of the arrangement. To the extent total future royalties collected are an amount less than the liability, the Company is not obligated to fund any such shortfall. We will periodically assess the expected royalty payments using projections from external sources. To the extent our estimates of future royalty payments are greater or less than previous estimates or the estimated timing of such payments is materially different than previous estimates, we will adjust the effective interest rate and recognize related non-cash interest expense on a prospective basis. We are not obligated to repay the proceeds received under the Royalty Purchase Agreement with HCR. Due to our continuing involvement under the Collaboration and License Agreement originally between Trubion and Wyeth , we continue to recognize royalty revenue on net sales of RUXIENCE and record the royalty payments to HCR as a reduction of the liability when paid. As such payments are made to HCR, the balance of the liability will be effectively repaid over the life of the Royalty Purchase Agreement. Debt Modification On March 30, 2021, we amended The amended Credit Agreement was accounted for under ASC 470-50, Debt Modifications and Extinguishments as a , rather than an extinguishment, based on a comparison of the present value of the cash flows under the terms of the debt immediately before and after the amendment, which resulted in a change of less than 10%. Unamortized issuance costs as of the date of modification will be amortized to interest expense using the effective interest method over the repayment term. Other Significant Accounting Policies Our other significant accounting policies were reported in our Annual Report on Form 10-K for the year ended December 31, 2020 that was filed with the SEC on March 31, 2021 and further amended on April 28, 2021. Our other significant accounting policies have not changed materially from the policies previously reported.

Discontinued Operations

Discontinued Operations	9 Months Ended
	Sep. 30, 2021
Discontinued Operations And Disposal Groups [Abstract]
Discontinued Operations	Note 2. Discontinued Operations The accompanying financial statements include discontinued operations from two separate transactions: the sale of our hyperimmune business in 2017, from which we received a payment in March 2021 related to the collection of a certain accounts receivable, and the sale of our Aptevo BioTherapeutics LLC business in February 2020. On February 28, 2020, we entered into an LLC Purchase Agreement with Medexus, pursuant to which we sold all of the issued and outstanding limited liability company interests of Aptevo BioTherapeutics LLC, a wholly owned subsidiary of Aptevo. As a result of the transaction, Medexus obtained all rights, title and interest to the IXINITY product and the related Hemophilia B business and intellectual property . The net gain on sale of Aptevo BioTherapeutics, totaling $14.3 million, was calculated as the difference between the fair value of the consideration received for Aptevo BioTherapeutics, less the net carrying value of the assets transferred to Medexus, less the transaction costs incurred and a working capital adjustment. We recorded the gain on sale in the quarter ended March 31, 2020. The following table represents the components attributable to income from discontinued operations in the unaudited condensed consolidated statements of operations (in thousands): For the Three Months Ended September, For the Nine Months Ended September, 2021 2020 2021 2020 Loss from operations - Aptevo BioTherapeutics — — — (1,580 ) Gain on sale of Aptevo BioTherapeutics — — — 14,338 Payment from Saol — — 227 — Deferred payment from Medexus 80 157 399 297 Income from discontinued operations $ 80 $ 157 $ 626 $ 13,055 The LLC Purchase Agreement with Medexus entitles us to future deferred payments and royalties. For the three months ended September 30, 2021, we collected Medexus communicated their third quarter 2021 net IXINITY sales to Aptevo in October and expects to make an immaterial deferred payment, within 45 days after quarter-end per the LLC Purchase Agreement, to Aptevo. As such, we will record the deferred payment amount related to Medexus’ third quarter sales of IXINITY as a gain when collected. There was no amortization for Aptevo BioTherapeutics in the three or nine months ended September 30, 2021 and amortization was $0.1 million for the three and nine months ended September 30, 2020. There was no depreciation or capital expenditures for the three or nine months ended September 30, 2021 or September 30, 2020. Significant operating non-cash items include the gain on sale of Aptevo BioTherapeutics of $14.3 million for the nine months ended September 30, 2020. There were no significant investing non-cash items for the nine months ended September 30, 2021 and 2020.

Collaboration Agreements

Collaboration Agreements	9 Months Ended
	Sep. 30, 2021
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Collaboration Agreements	Note 3. Collaboration Agreements Alligator 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 will collaboratively develop 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. We recorded approximately $0.1 million increase in research and development expense 30, 2020

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2021
Fair Value Disclosures [Abstract]
Fair Value Measurements	Note 4. 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, it 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. At September 30, 2021 and December 31, 2020, we had $47.9 million and $35.4 million in Level 1 money market funds, respectively. The carrying amounts of our money market funds approximate their fair value. At September 30, 2021 and December 31, 2020, we did not have any Level 2 or Level 3 assets.

Cash, Cash Equivalents, and Res

Cash, Cash Equivalents, and Restricted Cash	9 Months Ended
	Sep. 30, 2021
Cash And Cash Equivalents [Abstract]
Cash, Cash Equivalents, and Restricted Cash	Note 5. Cash, Cash Equivalents, and Restricted Cash The Company’s 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. Restricted cash - current includes $1.3 million securing letters of credit. The following table shows our cash, cash equivalents and current restricted cash as of September 30, 2021 and December 31, 2020: September 30, December 31, (in thousands) 2021 2020 Cash $ 4,218 $ 4,601 Cash equivalents 47,900 35,378 Restricted cash - current 1,259 2,555 Total cash, cash equivalents, and restricted cash $ 53,377 $ 42,534

Debt

Debt	9 Months Ended
	Sep. 30, 2021
Debt Disclosure [Abstract]
Debt	Note 6. Debt Credit Agreement On February 28, 2020, we used the proceeds from the sale of Aptevo BioTherapeutics to Medexus to repay $20 million outstanding principal under the Credit and Security Agreement, including payment of $2.1 million in an end of facility fee, accrued interest, legal fees, and prepayment fees. On August 5, 2020, we entered into a Credit and Security Agreement (the Credit Agreement), with MidCap Financial. 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 The United Kingdom’s Financial Conduct Authority (FCA), which regulates LIBOR, has announced that it intends to phase out one-week and two-month US Dollar LIBOR settings on December 31, 2021. All other US Dollar LIBOR settings, including the overnight, one-month, three-month, six-month and twelve-month, will be phased out on June 30, 2023. It is unclear if at that time LIBOR will cease to exist or if new methods of calculating LIBOR will be established such that it continues to exist after 2023. Our Credit Agreement with MidCap Financial currently references one-month LIBOR and also provides that we may amend the Credit Agreement to reflect an alternative rate of interest upon the phase out of LIBOR On November 6, 2020, Kevin Tang and his related entities filed a statement on Schedule 13D to report the purchase of 1,760,000 shares of the Company’s common stock, which at the time represented approximately 54% of the Company’s issued and outstanding shares of the Company’s common stock. This acquisition of voting stock triggered a change in control, resulting in an Event of Default under Section 10.1(a)(ii) of the Credit Agreement. On November 10, 2020, the Company obtained a waiver from MidCap Financial pursuant to which, among other things, MidCap Financial waived such Event of Default and MidCap Financial and the Company agreed that an immediate event of default under the Credit Agreement will be deemed to have occurred in the event that (a) a majority of the seats on the Company’s board of directors are occupied by persons who were neither (i) nominated by the Company’s board of directors nor (ii) appointed by the directors so nominated, and (b) Tang has appointed the majority of the Company’s board of directors. No other events of default have occurred with respect to the Credit Agreement. On March 30, 2021, we amended our Credit Agreement with MidCap Financial and used $10.0 million of the proceeds received from the Royalty Purchase Agreement to pay down the outstanding principal under the Credit Agreement from $25.0 million to $15.0 million. $10.0 million of the remaining $15.0 million principal balance will be payable on March 31, 2022. Beginning March 1, 2022, monthly repayment of the remaining $5.0 million of principal will commence and continue for the final 30 months of the loan term. If the Company sells the IXINITY deferred payment stream and milestones prior to full repayment of this $5.0 million principal amount, under the agreement with MidCap Financial, we will be required to use the proceeds from the sale to pay down the outstanding loan principal balance. MidCap Financial also released its security interest in the RUXIENCE royalty payments. A fee of $0.6 million was paid by the Company to MidCap Financial in connection with the amendment in lieu of the formula-based fee previously required. The amended Credit Agreement was accounted for as a debt modification As of September 30, 2021, we classified $11.2 million of the remaining $15.0 million principal of the amended Credit Agreement to current portion of long-term debt on the unaudited condensed consolidated balance sheet. The amended Credit Agreement states $10.0 million of the remaining $15.0 million principal balance will be payable on March 31, 2022. Additionally, within the next twelve months, we will pay $1.2 million to MidCap Financial for monthly repayments of outstanding principal beginning on March 1, 2022. This facility is subject to a subjective acceleration clause that could be invoked by MidCap Financial upon the occurrence of any event MidCap Financial deems to have a material adverse effect on our ability to repay the lender.

Liability Related to Sale of Fu

Liability Related to Sale of Future Royalties	9 Months Ended
	Sep. 30, 2021
Sale Of Future Royalties Liability Disclosure [Abstract]
Liability Related to Sale of Future Royalties	Note 7. Liability Related to Sale of Future Royalties In March 2021, we are eligible to receive additional payments in aggregate of up to an additional $32.5 million based on the achievement of sales milestones in 2021, 2022, and 2023 (collectively, the Milestone Amounts) The proceeds received from HCR of $35.0 million were recorded as a liability, net of transaction costs of $1.1 million, which will be amortized over the estimated life of the arrangement using the effective interest method. In order to determine the amortization of the liability, we are required to estimate the total amount of future royalty payments to be received by HCR over the life of the arrangement. The total amount of royalty payments received by HCR under the Royalty Purchase Agreement, less the net proceeds we received of $33.9 million, is recorded as non-cash interest expense over the life of the arrangement using the effective interest method. We maintain our rights under the Definitive Agreement originally between Trubion and Wyeth, with the exception of the cash flows of the RUXIENCE royalty payments purchased by HCR. Due to our continuing involvement under the Definitive Agreement originally between Trubion and Wyeth , we continue to recognize royalty revenue on net sales of RUXIENCE and record the royalty payments to HCR as a reduction of the liability when paid. As such payments are made to HCR, the balance of the liability will be effectively repaid over the life of the Royalty Purchase Agreement. To the extent total future royalties collected are an amount less than the liability, the Company is not obligated to fund any such shortfall. We estimate the effective interest rate used to record non-cash interest expense under the Royalty Purchase Agreement based on the estimate of future royalty payments to be received by HCR. As of September 30, 2021, the estimated effective interest rate under the agreement was 21.9%. Over the life of the arrangement, the actual effective interest rate will be affected by the amount and timing of the royalty payments received by HCR and changes in our forecasted royalties. Periodically, we will reassess our estimate of total future royalty payments to be received by HCR, and prospectively adjust the effective interest rate and amortization of the liability as necessary. The following table presents the changes in the liability in the quarter related to the sale of future royalties under the Royalty Purchase Agreement with HCR (in thousands): Three Months Ended September 30, 2021 Liability related to sale of future royalties, beginning balance $ 33,349 Non-cash interest expense 1,841 RUXIENCE royalties paid to HCR (3,110 ) Liability related to sale of future royalties, ending balance 32,080 Current portion of liability related to sale of future royalties (13,369 ) Liability related to sale of future royalties, non-current $ 18,711

Leases

Leases	9 Months Ended
	Sep. 30, 2021
Leases [Abstract]
Leases	Note 8. Leases Office Space Lease - Operating We have an operating lease related to our office and laboratory space in Seattle, Washington. This lease was amended and extended in March 2019. The term of the amended lease is through April 2030 and we have 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. The lease was further amended, effective August 2019, to reduce the square footage of our rented area. The amended lease has a renewal option of two five-year For the three and nine months ended September 30, 2021, we recorded $0.2 million and $0.6 million, respectively, related to variable expenses. For the three and nine months ended September 30, 2020, we recorded $0.2 million and $0.5 million, respectively, related to variable expenses. Equipment Leases - Operating As of September 30, 2021, we have operating leases for one piece of lab equipment and four copiers in our Seattle, Washington headquarters. The future expense for these leases will be straight-line and will include any variable expenses that arise. Equipment Lease – Financing As of September 30, 2021, we had one equipment lease classified as a financing lease as the lease transferred ownership of the underlying asset to us at the end of the lease term in 2020. The lease has no remaining expense obligation. There were no financing lease payments in the three months or nine months ended September 30, 2021. Components of lease expense: For the Three Months Ended September 30, For the Nine Months Ended September 30, For the Three Months Ended September 30, For the Nine Months Ended September 30, (in thousands) 2021 2021 2020 2020 Operating lease cost $ 395 $ 1,185 $ 395 $ 1,185 Finance lease cost: Amortization of right-of-use assets 2 5 2 5 Interest on lease liabilities — — — 1 Total lease cost $ 397 $ 1,190 $ 397 $ 1,191 Right of use assets acquired under operating leases: As of September 30, As of December 31, (in thousands) 2021 2020 Operating leases, excluding Seattle office lease $ 21 $ 122 Seattle office lease, including amendment 1,844 2,600 Total operating leases $ 1,865 $ 2,722 Lease payments: For the Nine Months Ended September 30, For the Nine Months Ended September 30, (in thousands) 2021 2020 For operating leases $ 1,053 $ 1,134 The long-term portion of the lease liabilities included in the amounts above is $1.6 million and the remainder of our lease liabilities are included in other current liabilities on our unaudited condensed consolidated balance sheets. As of September 30, 2021, the weighted average remaining lease term and weighted average discount rate for operating leases was 1.6 years and 14.46%. As of September 30, 2020, the weighted average remaining lease term and weighted average discount rate for operating leases was 2.5 years and 14.53%.

Net Income (Loss) per Share

Net Income (Loss) per Share	9 Months Ended
	Sep. 30, 2021
Earnings Per Share [Abstract]
Net Income (Loss) per Share	Note 9. 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. 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 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. Therefore, no dilutive effect has been recognized in the calculation of income from discontinued operations per share. 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 Three Months Ended September 30, For the Nine Months Ended September 30, 2021 2020 2021 2020 Net loss from continuing operations $ (7,077 ) $ (6,948 ) $ (22,811 ) $ (23,752 ) Income from discontinued operations 80 157 626 13,055 Net loss $ (6,997 ) $ (6,791 ) $ (22,185 ) $ (10,697 ) Basic and diluted net income (loss) per share: Net loss from continuing operations $ (1.45 ) $ (2.15 ) $ (4.94 ) $ (7.35 ) Net income from discontinued operations $ 0.02 $ 0.05 $ 0.14 $ 4.04 Net loss per basic share $ (1.43 ) $ (2.10 ) $ (4.80 ) $ (3.31 ) Weighted-average shares used to compute per share calculations 4,891,881 3,232,811 4,617,357 3,233,257 The following table represents all potentially dilutive shares, which were all anti-dilutive and therefore excluded from the calculation of diluted net loss per share: As of September 30, (in thousands) 2021 2020 Warrants 351 1,571 Outstanding options to purchase common stock 350 230 Unvested RSUs 64 11

Equity

Equity	9 Months Ended
	Sep. 30, 2021
Equity [Abstract]
Equity	Note 10. Equity Equity Distribution Agreement On December 14, 2020, we entered into an Equity Distribution Agreement (the Equity Distribution Agreement) with Piper Sandler. The Equity Distribution Agreement provides 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 supersedes and replaces the program we commenced in December 2017. Lincoln Park Purchase Agreement On December 20, 2018, we entered into a Purchase Agreement, and a registration rights agreement, with Lincoln Park (the Purchase Agreement). Pursuant to the Purchase Agreement, Lincoln Park has committed to purchase up to $35.0 million worth of our common stock over a 36-month period commencing on February 13, 2019, the date the registration statement covering the resale of the shares was declared effective by the SEC. Under the Purchase Agreement, on any business day selected by us, we may direct Lincoln Park to purchase shares of our common stock provided that Lincoln Park’s maximum commitment on any single day does not exceed $2.0 million. The purchase price per share will be based off of prevailing market prices of our common stock immediately preceding the time of sale; provided, however, that we cannot direct any such purchase if the prevailing market price is less than $1.00. In the nine months ended September 30, 2021, the Company issued approximately 0.4 million shares of common stock to Lincoln Park under the Purchase Agreement. We received $10.2 million in proceeds from issuance of these shares and now have a remaining $24.8 million worth of shares of our common stock that we may direct Lincoln Park to purchase pursuant to the Purchase Agreement Rights Plan On November 8, 2020, our Board of Directors (Board) approved and adopted a 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. 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, at an exercise price of $400.00 per one one-thousandth of a Series A Junior Participating Preferred Share, subject to adjustment. 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. The Rights Agreement was amended on November 4, 2021 to extend the expiration date of such agreement from November 8, 2021 to November 5, 2022. C onverted Equity Awards Incentive Plan In connection with the spin-off from Emergent BioSolutions, Inc. (Emergent) in August 2016, we adopted the Converted Equity Awards Incentive Plan (Converted Plan) and outstanding equity awards of Emergent held by Aptevo employees were converted into or replaced with equity awards of Aptevo (Conversion Awards). A total of 0.1 million shares of Aptevo common stock have been authorized for issuance under the Converted Plan. 2016 Stock Incentive Plan On August 1, 2016, the Company adopted the 2016 Stock Incentive Plan (2016 SIP). A total of 0.2 million shares of Aptevo common stock have been authorized for issuance under the 2016 SIP in the form of equity stock options. On May 31, 2017, at the 2017 Annual Meeting of Stockholders (Annual Meeting), the Company’s stockholders approved the amendment and restatement of the Company’s 2016 SIP (Restated 2016 Plan) to, among other things, increase the number of authorized shares issuable by 0.1 million shares of Aptevo common stock. The Restated 2016 Plan was previously approved, subject to stockholder approval, by the Board of Directors of the Company. 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 (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. As of September 30, 2021, there are less than 0.1 million shares available to be granted under the 2018 SIP. Stock options under the 2018 SIP generally vest pro rata over a three-year three-year 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 unaudited condensed consolidated statements of operations as follows: For the Three Months Ended September 30, For the Nine Months Ended September 30, (in thousands) 2021 2020 2021 2020 Research and development $ 80 $ 138 $ 491 $ 422 General and administrative 239 205 973 635 Total stock-based compensation expense $ 319 $ 343 $ 1,464 $ 1,057 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 nonemployee options are generally consistent with the assumptions used for options granted to employees. In the event the Company terminates any of its consulting agreements, the unvested options underlying the agreements would also be cancelled. 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 Three Months Ended September 30, For the Nine Months Ended September 30, 2021 2020 2021 2020 Expected dividend yield 0.00% 0.00% 0.00% 0.00% Expected volatility 97.59% 91.44% 99.30% 87.77% Risk-free interest rate 0.96% 2.46% 2.73% 1.97% Expected average life of options 6 years 8 years 5 years 8 years Management has applied an estimated forfeiture rate of 20% and 22% for the three and nine months ended September 30, 2021 and 18% and 13% for the three and nine months ended September 30, 2020, respectively. The following is a summary of option activity for the nine months ended September 30, 2021: Number of Shares Weighted- Average Exercise Price Weighted- Average Remaining Term Aggregate Intrinsic Value Balance at December 31, 2020 212,581 $ 8.32 8.78 $ 5,906,007 Granted 218,061 31.44 — — Exercised (23,698 ) 8.44 — 398,882 Forfeited (57,245 ) 29.21 — — Outstanding at September 30, 2021 349,699 $ 19.60 8.84 $ 1,258,263 Exercisable at September 30, 2021 120,133 $ 8.45 8.10 $ 845,986 As of September 30, 2021, we had $3.8 million of unrecognized compensation expense related to options expected to vest over a weighted average period of 2.3 years. The weighted average remaining contractual life of outstanding and exercisable options is 8.1 years. 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 September 2021 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 RSU activity for the nine months ended September 30, 2021: Number of Units Weighted Average Fair Value per Unit Balance at December 31, 2020 9,000 $ 41.00 Granted 80,304 30.49 Forfeited (25,353 ) 33.04 Outstanding at September 30, 2021 63,951 $ 34.59 Expected to Vest 63,951 $ 34.59 As of September 30, 2021, there was $1.7 million unrecognized stock-based compensation expense related to unvested RSUs. 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. Warrants 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 ten-year

Nature of Business and Signif_2

Nature of Business and Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2021
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles (GAAP). These unaudited condensed consolidated financial statements include all adjustments, which include normal recurring adjustments, necessary for the fair presentation of the Company’s financial position. These unaudited interim consolidated financial statements should be read in conjunction with the audited consolidated financial statements as of and for the year ended December 31, 2020, and the notes thereto, which are included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2020. 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 unaudited condensed consolidated financial statements include the accounts of the Company and our wholly owned subsidiaries: Aptevo Research and Development LLC and Aptevo BioTherapeutics LLC (for the period prior to its sale on February 28, 2020) In March 2020, we effected a 1-for-14 reverse stock split (the “Reverse Split”) of our common stock pursuant to which every 14 shares of our common stock issued and outstanding as of March 26, 2020 were automatically combined into one issued and outstanding share of common stock. No fractional shares were issued as a result of the reverse stock split. Stockholders of record who would otherwise have been entitled to receive a fractional share received a cash payment in lieu thereof. All share and per share information with respect to our common stock have been restated to reflect the effect of the Reverse Split for all periods presented.
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 unaudited condensed consolidated financial statements and accompanying notes. Estimates are used for, but not limited to, forecasted royalties, effective interest rates, clinical accruals, useful lives of equipment, commitments and contingencies, and stock-based compensation forfeiture rates. Given the global economic climate and additional or unforeseen effects from the ongoing COVID-19 pandemic, these estimates are becoming more challenging, and actual results could differ materially from those estimates.
Liability Related to Sale of Future Royalties and Non-Cash Interest Expense	Liability Related to Sale of Future Royalties and Non-Cash Interest Expense On March 30, 2021, the Company entered into and closed a royalty purchase agreement (the Royalty Purchase Agreement) with an entity managed by HealthCare Royalty Management, LLC (HCR) the Company is eligible to receive additional payments in aggregate of up to an additional $32.5 million based on the achievement of sales milestones in 2021, 2022, and 2023 (collectively, the Milestone Amounts) We treat the Royalty Purchase Agreement with HCR (see Note 7) as a debt financing, amortized under the effective interest rate method over the estimated life of the related expected royalty stream. The liabilities related to the sale of future royalties and the debt amortization are based on our current estimates of future royalties expected to be paid over the life of the arrangement. To the extent total future royalties collected are an amount less than the liability, the Company is not obligated to fund any such shortfall. We will periodically assess the expected royalty payments using projections from external sources. To the extent our estimates of future royalty payments are greater or less than previous estimates or the estimated timing of such payments is materially different than previous estimates, we will adjust the effective interest rate and recognize related non-cash interest expense on a prospective basis. We are not obligated to repay the proceeds received under the Royalty Purchase Agreement with HCR. Due to our continuing involvement under the Collaboration and License Agreement originally between Trubion and Wyeth , we continue to recognize royalty revenue on net sales of RUXIENCE and record the royalty payments to HCR as a reduction of the liability when paid. As such payments are made to HCR, the balance of the liability will be effectively repaid over the life of the Royalty Purchase Agreement.
Debt Modification	Debt Modification On March 30, 2021, we amended The amended Credit Agreement was accounted for under ASC 470-50, Debt Modifications and Extinguishments as a , rather than an extinguishment, based on a comparison of the present value of the cash flows under the terms of the debt immediately before and after the amendment, which resulted in a change of less than 10%. Unamortized issuance costs as of the date of modification will be amortized to interest expense using the effective interest method over the repayment term.
Other Significant Accounting Policies	Other Significant Accounting Policies Our other significant accounting policies were reported in our Annual Report on Form 10-K for the year ended December 31, 2020 that was filed with the SEC on March 31, 2021 and further amended on April 28, 2021. Our other significant accounting policies have not changed materially from the policies previously reported.

Discontinued Operations (Tables

Discontinued Operations (Tables)	9 Months Ended
	Sep. 30, 2021
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 unaudited condensed consolidated statements of operations (in thousands): For the Three Months Ended September, For the Nine Months Ended September, 2021 2020 2021 2020 Loss from operations - Aptevo BioTherapeutics — — — (1,580 ) Gain on sale of Aptevo BioTherapeutics — — — 14,338 Payment from Saol — — 227 — Deferred payment from Medexus 80 157 399 297 Income from discontinued operations $ 80 $ 157 $ 626 $ 13,055

Cash, Cash Equivalents, and R_2

Cash, Cash Equivalents, and Restricted Cash (Tables)	9 Months Ended
	Sep. 30, 2021
Cash And Cash Equivalents [Abstract]
Schedule of Cash, Cash Equivalents and Current Restricted Cash	The following table shows our cash, cash equivalents and current restricted cash as of September 30, 2021 and December 31, 2020: September 30, December 31, (in thousands) 2021 2020 Cash $ 4,218 $ 4,601 Cash equivalents 47,900 35,378 Restricted cash - current 1,259 2,555 Total cash, cash equivalents, and restricted cash $ 53,377 $ 42,534

Liability Related to Sale of _2

Liability Related to Sale of Future Royalties (Tables)	9 Months Ended
	Sep. 30, 2021
Sale Of Future Royalties Liability Disclosure [Abstract]
Schedule of Changes in the Liability Related to the Sale of Future Royalties	The following table presents the changes in the liability in the quarter related to the sale of future royalties under the Royalty Purchase Agreement with HCR (in thousands): Three Months Ended September 30, 2021 Liability related to sale of future royalties, beginning balance $ 33,349 Non-cash interest expense 1,841 RUXIENCE royalties paid to HCR (3,110 ) Liability related to sale of future royalties, ending balance 32,080 Current portion of liability related to sale of future royalties (13,369 ) Liability related to sale of future royalties, non-current $ 18,711

Leases (Tables)

Leases (Tables)	9 Months Ended
	Sep. 30, 2021
Leases [Abstract]
Components of Lease Expense	Components of lease expense: For the Three Months Ended September 30, For the Nine Months Ended September 30, For the Three Months Ended September 30, For the Nine Months Ended September 30, (in thousands) 2021 2021 2020 2020 Operating lease cost $ 395 $ 1,185 $ 395 $ 1,185 Finance lease cost: Amortization of right-of-use assets 2 5 2 5 Interest on lease liabilities — — — 1 Total lease cost $ 397 $ 1,190 $ 397 $ 1,191
Summary of Right of Use Assets Acquired Under Operating Leases	Right of use assets acquired under operating leases: As of September 30, As of December 31, (in thousands) 2021 2020 Operating leases, excluding Seattle office lease $ 21 $ 122 Seattle office lease, including amendment 1,844 2,600 Total operating leases $ 1,865 $ 2,722 Lease payments: For the Nine Months Ended September 30, For the Nine Months Ended September 30, (in thousands) 2021 2020 For operating leases $ 1,053 $ 1,134

Net Income (Loss) per Share (Ta

Net Income (Loss) per Share (Tables)	9 Months Ended
	Sep. 30, 2021
Earnings Per Share [Abstract]
Computation of Basic and Diluted Net 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 Three Months Ended September 30, For the Nine Months Ended September 30, 2021 2020 2021 2020 Net loss from continuing operations $ (7,077 ) $ (6,948 ) $ (22,811 ) $ (23,752 ) Income from discontinued operations 80 157 626 13,055 Net loss $ (6,997 ) $ (6,791 ) $ (22,185 ) $ (10,697 ) Basic and diluted net income (loss) per share: Net loss from continuing operations $ (1.45 ) $ (2.15 ) $ (4.94 ) $ (7.35 ) Net income from discontinued operations $ 0.02 $ 0.05 $ 0.14 $ 4.04 Net loss per basic share $ (1.43 ) $ (2.10 ) $ (4.80 ) $ (3.31 ) Weighted-average shares used to compute per share calculations 4,891,881 3,232,811 4,617,357 3,233,257
Summary of Potentially Dilutive Shares Excluded from Calculation of Net Loss Per Share	The following table represents all potentially dilutive shares, which were all anti-dilutive and therefore excluded from the calculation of diluted net loss per share: As of September 30, (in thousands) 2021 2020 Warrants 351 1,571 Outstanding options to purchase common stock 350 230 Unvested RSUs 64 11

Equity (Tables)

Equity (Tables)	9 Months Ended
	Sep. 30, 2021
Equity [Abstract]
Summary of Stock-based Compensation Expense Includes Amortization of Stock Options and Restricted Stock Units Granted	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 unaudited condensed consolidated statements of operations as follows: For the Three Months Ended September 30, For the Nine Months Ended September 30, (in thousands) 2021 2020 2021 2020 Research and development $ 80 $ 138 $ 491 $ 422 General and administrative 239 205 973 635 Total stock-based compensation expense $ 319 $ 343 $ 1,464 $ 1,057
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 Three Months Ended September 30, For the Nine Months Ended September 30, 2021 2020 2021 2020 Expected dividend yield 0.00% 0.00% 0.00% 0.00% Expected volatility 97.59% 91.44% 99.30% 87.77% Risk-free interest rate 0.96% 2.46% 2.73% 1.97% Expected average life of options 6 years 8 years 5 years 8 years
Summary of Stock Option Activity	The following is a summary of option activity for the nine months ended September 30, 2021: Number of Shares Weighted- Average Exercise Price Weighted- Average Remaining Term Aggregate Intrinsic Value Balance at December 31, 2020 212,581 $ 8.32 8.78 $ 5,906,007 Granted 218,061 31.44 — — Exercised (23,698 ) 8.44 — 398,882 Forfeited (57,245 ) 29.21 — — Outstanding at September 30, 2021 349,699 $ 19.60 8.84 $ 1,258,263 Exercisable at September 30, 2021 120,133 $ 8.45 8.10 $ 845,986
Summary of RSU Activity	The following is a summary of RSU activity for the nine months ended September 30, 2021: Number of Units Weighted Average Fair Value per Unit Balance at December 31, 2020 9,000 $ 41.00 Granted 80,304 30.49 Forfeited (25,353 ) 33.04 Outstanding at September 30, 2021 63,951 $ 34.59 Expected to Vest 63,951 $ 34.59

Nature of Business and Signif_3

Nature of Business and Significant Accounting Policies - Additional Information (Details) $ in Thousands	Mar. 26, 2020	Mar. 31, 2021USD ($)	Mar. 30, 2021USD ($)	Mar. 31, 2020	Sep. 30, 2021USD ($)	Jun. 30, 2021USD ($)	Mar. 31, 2021USD ($)	Sep. 30, 2020USD ($)	Jun. 30, 2020USD ($)	Mar. 31, 2020USD ($)shares	Sep. 30, 2021USD ($)	Sep. 30, 2020USD ($)	Dec. 31, 2020USD ($)
Debt Instrument [Line Items]
Net income (loss) for the period					$ (6,997)	$ (7,932)	$ (7,256)	$ (6,791)	$ (6,803)	$ 2,897	$ (22,185)	$ (10,697)
Accumulated deficit					(207,791)						(207,791)		$ (185,606)
Net cash used in operating activities											(17,799)	$ (23,195)
Reverse stock split description				we effected a 1-for-14 reverse stock split (the “Reverse Split”) of our common stock pursuant to which every 14 shares of our common stock issued and outstanding as of March 26, 2020 were automatically combined into one issued and outstanding share of common stock. No fractional shares were issued as a result of the reverse stock split.
Stock split, conversion ratio	0.071
Fractional shares reverse stock split | shares										0
Proceeds from Sale of Investments		$ 35,000	$ 35,000
Payment of royalty purchase agreement		190.00%	190.00%
Payment of royalty interest		50.00%	50.00%
Payment Of Amount Outstanding		$ 10,000
R U X I E N C E | Maximum
Debt Instrument [Line Items]
Revenue from related Parties		32,500	$ 32,500
H C R | Mid Cap Financial
Debt Instrument [Line Items]
Proceeds from sale of investments used		10,000	10,000
Payment Of Amount Outstanding		15,000
H C R | Maximum | Mid Cap Financial
Debt Instrument [Line Items]
Payment Of Amount Outstanding		25,000	25,000
H C R | Minimum [Member] | Mid Cap Financial
Debt Instrument [Line Items]
Payment Of Amount Outstanding		$ 15,000	$ 15,000
Nasdaq Capital Market
Debt Instrument [Line Items]
Net income (loss) for the period					(7,000)						(22,200)
Accumulated deficit					$ (207,800)						(207,800)
Net cash used in operating activities											$ (17,800)

Discontinued Operations - Addit

Discontinued Operations - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Mar. 31, 2020	Sep. 30, 2021	Sep. 30, 2020
Discontinued Operations And Disposal Groups [Abstract]
Net gain on sale of business			$ 14,300		$ 14,338
Deferred payment from Medexus	$ 80	$ 157		$ 399	297
Amortization	0	100		0	100
Depreciation or capital expenditure	$ 0	$ 0		0	0
Investing non-cash items				$ 0	$ 0

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	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Discontinued Operations And Disposal Groups [Abstract]
Loss from operations - Aptevo BioTherapeutics				$ (1,580)
Gain on sale of Aptevo BioTherapeutics				14,338
Milestone payment			$ 227
Deferred payment from Medexus	$ 80	$ 157	399	297
Income from discontinued operations	$ 80	$ 157	$ 626	$ 13,055

Collaboration Agreements - Addi

Collaboration Agreements - Additional Information (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Reduction in research and development expense	$ 0.1	$ 0.1

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Details) - USD ($)	Sep. 30, 2021	Dec. 31, 2020
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Money market funds	$ 47,900,000	$ 35,400,000
Level Two
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value assets	0	0
Level Three
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value assets	$ 0	$ 0

Cash, Cash Equivalents and Rest

Cash, Cash Equivalents and Restricted Cash - Additional Information (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Dec. 31, 2020
Restricted Cash And Cash Equivalents Items [Line Items]
Current restricted cash	$ 1,259	$ 2,555
Maximum
Restricted Cash And Cash Equivalents Items [Line Items]
Cash equivalents, maturity period	90 days
Letter of Credit
Restricted Cash And Cash Equivalents Items [Line Items]
Current restricted cash	$ 1,300

Cash, Cash Equivalents and Re_2

Cash, Cash Equivalents and Restricted Cash - Schedule of Cash, Cash Equivalents and Current Restricted Cash (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Cash And Cash Equivalents [Abstract]
Cash	$ 4,218	$ 4,601
Cash equivalents	47,900	35,378
Restricted cash - current	1,259	2,555
Total cash, cash equivalents, and restricted cash	$ 53,377	$ 42,534

Debt - Additional Information (

Debt - Additional Information (Details) - USD ($) $ in Thousands	Mar. 01, 2022	Nov. 06, 2020	Aug. 05, 2020	Feb. 28, 2020	Mar. 31, 2022	Mar. 31, 2021	Mar. 30, 2021	Sep. 30, 2021	Sep. 30, 2020
Line Of Credit Facility [Line Items]
Maximum borrowing capacity			$ 25,000
Payment Of Amount Outstanding						$ 10,000
Repayments of subordinated debt								$ 10,550	$ 22,104
H C R
Line Of Credit Facility [Line Items]
Principal balance payable date						Mar. 31, 2022
Tang
Line Of Credit Facility [Line Items]
Purchase of shares of common stock		1,760,000
Percentage of common stock shares issued and outstanding		54.00%
Business acquisition, description		This acquisition of voting stock triggered a change in control, resulting in an Event of Default under Section 10.1(a)(ii) of the Credit Agreement. On November 10, 2020, the Company obtained a waiver from MidCap Financial pursuant to which, among other things, MidCap Financial waived such Event of Default and MidCap Financial and the Company agreed that an immediate event of default under the Credit Agreement will be deemed to have occurred in the event that (a) a majority of the seats on the Company’s board of directors are occupied by persons who were neither (i) nominated by the Company’s board of directors nor (ii) appointed by the directors so nominated, and (b) Tang has appointed the majority of the Company’s board of directors. No other events of default have occurred with respect to the Credit Agreement.
Credit Agreement [Member]
Line Of Credit Facility [Line Items]
Line of credit facility, used borrowing capacity			$ 25,000
Payment Of Amount Outstanding								11,200
Remaining Principal Balance Payable								$ 15,000
Credit Agreement [Member] | Scenario Forecast
Line Of Credit Facility [Line Items]
Payment Of Amount Outstanding					$ 10,000
Remaining Principal Balance Payable					$ 15,000
Credit Agreement [Member] | London Interbank Offered Rate LIBOR [Member]
Line Of Credit Facility [Line Items]
Line of credit facility, borrowing capacity, description			The term loan facility has a 48 month term, is interest-only for the first 18 months, with straight-line amortization for the remaining 30 months and bears interest at a rate of one month LIBOR plus 6.25% per annum, subject to a 1.50% LIBOR floor and a 2.50% LIBOR cap.
Interest rate			6.25%
Floor interest rate			1.50%
Cap interest rate			2.50%
Mid Cap Financial
Line Of Credit Facility [Line Items]
Principal payment of full term debt facility				$ 20,000
Facility Fee				$ 2,100
Repayments of subordinated debt						$ 5,000
Amendment in lieu of the formula-based fee						600
Mid Cap Financial | Scenario Forecast
Line Of Credit Facility [Line Items]
Payment Of Amount Outstanding	$ 1,200
Mid Cap Financial | H C R
Line Of Credit Facility [Line Items]
Proceeds from sale of investments used						10,000	$ 10,000
Payment Of Amount Outstanding						15,000
Mid Cap Financial | H C R | Maximum
Line Of Credit Facility [Line Items]
Payment Of Amount Outstanding						25,000	25,000
Mid Cap Financial | H C R | Minimum [Member]
Line Of Credit Facility [Line Items]
Payment Of Amount Outstanding						$ 15,000	$ 15,000

Liability Related to Sale of _3

Liability Related to Sale of Future Royalties - Additional Information (Details) - USD ($) $ in Thousands	1 Months Ended		3 Months Ended
	Mar. 31, 2021	Mar. 30, 2021	Sep. 30, 2021	Mar. 31, 2021
Debt Instrument [Line Items]
Proceeds from Sale of Investments	$ 35,000	$ 35,000
Payment of royalty purchase agreement	190.00%	190.00%
Payment of royalty interest	50.00%	50.00%
Non-cash interest expense			$ 1,841
R U X I E N C E | Maximum
Debt Instrument [Line Items]
Revenue from related Parties	$ 32,500	$ 32,500
H C R
Debt Instrument [Line Items]
Transaction costs	$ 1,100			$ 1,100
Non-cash interest expense				33,900
Interest rate, effective percentage			21.90%
H C R | Liability
Debt Instrument [Line Items]
Proceeds from royalties received				$ 35,000

Schedule of Changes in the Liab

Schedule of Changes in the Liability Related to the Sale of Future Royalties (Details) $ in Thousands	3 Months Ended
	Sep. 30, 2021USD ($)
Debt Disclosure [Abstract]
Liability related to sale of future royalties, beginning balance	$ 33,349
Non-cash interest expense	1,841
RUXIENCE royalties paid to HCR	(3,110)
Liability related to sale of future royalties, ending balance	32,080
Current portion of liability related to sale of future royalties	(13,369)
Liability related to sale of future royalties, non-current	$ 18,711

Leases - Additional Information

Leases - Additional Information (Details)	Aug. 31, 2019RenewalOption	Sep. 30, 2021USD ($)	Sep. 30, 2020USD ($)	Sep. 30, 2021USD ($)RenewalOptionPieceCopierEquipment	Sep. 30, 2020USD ($)	Dec. 31, 2020USD ($)
Lessee Lease Description [Line Items]
Operating lease number of piece for lab equipment | Piece				1
Operating lease number of copiers | Copier				4
Financing lease number of equipment | Equipment				1
Financing lease payments		$ 0
Long term portion of operating lease liabilities		$ 1,610,000		$ 1,610,000		$ 2,360,000
Weighted average remaining lease term for operating leases		1 year 7 months 6 days	2 years 6 months	1 year 7 months 6 days	2 years 6 months
Weighted discount rate for operating leases		14.46%	14.53%	14.46%	14.53%
Office Space Lease
Lessee Lease Description [Line Items]
Initial operating lease term date				2030-04
Operating lease renewal option description				The term of the amended lease is through April 2030 and we have 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		5 years
Number of operating lease renewal option | RenewalOption	2			2
Operating lease option to extend				true
Operating lease termination option written notice period	9 months
Operating lease termination option unamortized tenant improvement allowance interest rate	8.00%
Operating lease termination option unamortized real estate taxes interest rate	8.00%
Variable expense		$ 200,000	$ 200,000	$ 600,000	$ 500,000
Office Space Lease | Renewal Option Two
Lessee Lease Description [Line Items]
Operating lease renewal option term		5 years		5 years

Leases - Components of Lease Ex

Leases - Components of Lease Expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Leases [Abstract]
Operating lease cost	$ 395	$ 395	$ 1,185	$ 1,185
Finance lease cost:
Amortization of right-of-use assets	2	2	5	5
Interest on lease liabilities				1
Total lease cost	$ 397	$ 397	$ 1,190	$ 1,191

Leases - Summary of Right of Us

Leases - Summary of Right of Use Assets Acquired Under Operating Leases (Details) - USD ($) $ in Thousands	9 Months Ended		12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Lessee Lease Description [Line Items]
Total operating leases	$ 1,865		$ 2,722
For operating leases	1,053	$ 1,134
Operating Leases, Excluding Seattle Office Lease
Lessee Lease Description [Line Items]
Total operating leases	21		122
Seattle Office Lease, Including Amendment
Lessee Lease Description [Line Items]
Total operating leases	$ 1,844		$ 2,600

Net Income (Loss) Per Share - C

Net Income (Loss) Per Share - Computation of Basic and Diluted Net Loss per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2021	Sep. 30, 2020
Earnings Per Share [Abstract]
Net loss from continuing operations	$ (7,077)			$ (6,948)			$ (22,811)	$ (23,752)
Income from discontinued operations	80			157			626	13,055
Net loss	$ (6,997)	$ (7,932)	$ (7,256)	$ (6,791)	$ (6,803)	$ 2,897	$ (22,185)	$ (10,697)
Basic and diluted net income (loss) per share:
Net loss from continuing operations per share	$ (1.45)			$ (2.15)			$ (4.94)	$ (7.35)
Net income from discontinued operations per share	0.02			0.05			0.14	4.04
Basic and diluted net loss per basic share	$ (1.43)			$ (2.10)			$ (4.80)	$ (3.31)
Weighted-average shares used to compute per share calculations	4,891,881			3,232,811			4,617,357	3,233,257

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	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Warrants
Schedule Of Earnings Per Share Basic And Diluted [Line Items]
Anti-dilutive shares excluded from calculation of diluted net loss per share	351,000	1,571,000
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	350,000	230,000
Unvested RSUs
Schedule Of Earnings Per Share Basic And Diluted [Line Items]
Anti-dilutive shares excluded from calculation of diluted net loss per share	64,000	11,000

Equity - Additional Information

Equity - Additional Information (Details) - USD ($)

Dec. 14, 2020

Nov. 08, 2020

Jun. 01, 2018

Mar. 31, 2019

Sep. 30, 2021

Jun. 30, 2021

Sep. 30, 2020

Sep. 30, 2021

Sep. 30, 2020

Dec. 31, 2018

Dec. 31, 2020

May 31, 2017

Aug. 01, 2016

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Common stock, par value

$ 0.001

$ 0.001

$ 0.001

Issuance of common stock shares

24.8

Issuance of common stock, net

$ 10,234,000

Proceeds from common stock issued pursuant to the Lincoln Park Purchase Agreement

$ 10,233,000

Common stock sold pursuant to the Lincoln Park Purchase Agreement (in shares)

24.8

Preferred 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

Unvested RSUs

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Unrecognized compensation expense

$ 1,700,000

$ 1,700,000

Stock Option

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Estimated forfeiture rate

20.00%

18.00%

22.00%

13.00%

Unrecognized compensation expense

$ 3,800,000

$ 3,800,000

Options expected to vest, weighted average period

2 years 3 months 18 days

Options outstanding and exercisable weighted average remaining contractual life

8 years 1 month 6 days

2016 Stock Incentive Plan

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Stock authorized for issuance under Stock Plan

200,000

2016 Stock Incentive Plan | Unvested RSUs

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Increase of authorized shares issuable

100,000

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

Maximum number of returning shares from old plan to be add to shares reserve

0.3

Stock plan vesting period

3 years

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

3 years

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]

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

Preferred stock exercise price

$ 400

Percentage of beneficial ownership

10.00%

Maximum | 2018 Stock Incentive Plan | Unvested RSUs

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Number of shares available for grant

100,000

Common Stock

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Issuance of common stock shares

407,047

Issuance of common stock, net

$ 1,000

Common stock sold pursuant to the Lincoln Park Purchase Agreement (in shares)

407,047

Common Stock | Converted Equity Awards Incentive Plan

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Stock authorized for issuance under Stock Plan

100,000

Warrants

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Warrants outstanding, term

5 years

Warrants outstanding

350,589

350,589

Warrants | Tranche One

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Preferred stock exercise price

$ 18.20

Number of warrants issued

1,571,429

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

Equity Distribution Agreement

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Common stock, par value

$ 0.001

Issuance of common stock shares

0

0

Common stock sold pursuant to the Lincoln Park Purchase Agreement (in shares)

0

0

Equity Distribution Agreement | Common Stock | Maximum

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Aggregate offering price

$ 50,000,000

Purchase Agreement | Common Stock

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Issuance of common stock, net

$ 35,000,000

Commitment to purchase shares of common stock, maximum amount

$ 2,000,000

Purchase Agreement | Common Stock | Lincoln Park

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Issuance of common stock shares

0.4

Common stock sold pursuant to the Lincoln Park Purchase Agreement (in shares)

0.4

Purchase Agreement | Common Stock | Minimum [Member]

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Minimum prevailing market price to direct purchase

$ 1

$ 1

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	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense	$ 319	$ 343	$ 1,464	$ 1,057
Research and Development
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense	80	138	491	422
General and Administrative
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense	$ 239	$ 205	$ 973	$ 635

Equity - Assumptions used in Va

Equity - Assumptions used in Valuing the Stock Options Granted under Black-Scholes Valuation Model (Details) - Stock Option	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected dividend yield	0.00%	0.00%	0.00%	0.00%
Expected volatility	97.59%	91.44%	99.30%	87.77%
Risk-free interest rate	0.96%	2.46%	2.73%	1.97%
Expected average life of options	6 years	8 years	5 years	8 years

Equity - Summary of Stock Optio

Equity - Summary of Stock Option Activity (Details) - Stock Option - USD ($)	9 Months Ended	12 Months Ended
	Sep. 30, 2021	Dec. 31, 2020
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of Shares, Outstanding, Beginning balance	212,581
Number of Shares, Granted	218,061
Number of Shares, Exercised	(23,698)
Number of Shares, Forfeited	(57,245)
Number of Shares, Outstanding, Ending balance	349,699	212,581
Number of Shares, Exercisable	120,133
Weighted-Average Exercise Price, Outstanding, Beginning balance	$ 8.32
Weighted-Average Exercise Price, Granted	31.44
Weighted-Average Exercise Price, Exercised	8.44
Weighted-Average Exercise Price, Forfeited	29.21
Weighted-Average Exercise Price, Outstanding, Ending balance	19.60	$ 8.32
Weighted-Average Exercise Price, Exercisable	$ 8.45
Weighted-Average Remaining Term, Outstanding	8 years 10 months 2 days	8 years 9 months 10 days
Weighted-Average Remaining Term, Exercisable	8 years 1 month 6 days
Aggregate Intrinsic Value, Outstanding, Beginning balance	$ 5,906,007
Aggregate Intrinsic Value, Exercised	398,882
Aggregate Intrinsic Value, Outstanding, Ending balance	1,258,263	$ 5,906,007
Aggregate Intrinsic Value, Exercisable	$ 845,986

Equity - Summary of Restricted

Equity - Summary of Restricted Stock Activity (Details) - Unvested RSUs	9 Months Ended
	Sep. 30, 2021$ / sharesshares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of Units, Outstanding, Beginning balance | shares	9,000
Number of Units, Granted | shares	80,304
Number of Units, Forfeited | shares	(25,353)
Number of Units, Outstanding, Ending balance | shares	63,951
Number of Units, Expected to Vest | shares	63,951
Weighted Average Fair Value per Unit, Outstanding Beginning Balance | $ / shares	$ 41
Weighted Average Fair Value per Unit, Granted | $ / shares	30.49
Weighted Average Fair Value per Unit, Forfeited | $ / shares	33.04
Weighted Average Fair Value per Unit, Outstanding Ending Balance | $ / shares	34.59
Weighted Average Fair Value per Unit, Expected to Vest | $ / shares	$ 34.59