Humanigen (HGENQ) 10-K 28 Feb 22 2021 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2021	Feb. 16, 2022	Jun. 30, 2021
Cover [Abstract]
Document Type	10-K
Entity Central Index Key	0001293310
Document Period End Date	Dec. 31, 2021
Document Fiscal Period Focus	FY
Amendment Flag	false
Document Fiscal Year Focus	2021
Current Fiscal Year End Date	--12-31
Document Annual Report	true
Document Transition Report	false
Entity File Number	001-35798
Entity Registrant Name	HUMANIGEN, INC
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	77-0557236
Entity Address, Address Line One	830 Morris Turnpike, 4th Floor
Entity Address, City or Town	Short Hills
Entity Address, State or Province	NJ
Entity Address, Postal Zip Code	07078
City Area Code	973
Local Phone Number	200-3100
Title of 12(b) Security	Common Stock
Trading Symbol	HGEN
Name of Exchange on which Security is Registered	NASDAQ
Entity Well-Known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Auditor Attestation Flag	false
Entity Shell Company	false
Entity Public Float			$ 710,884,199
Entity Common Stock, Shares Outstanding		65,329,177
Documents Incorporated By Reference Text Block	The definitive proxy statement relating to the registrant’s Annual Meeting of Stockholders to be held on June 9, 2022, is incorporated by reference in Part III to the extent described therein.
Auditor Name	HORNE LLP
Auditor Location	Ridgeland, Mississippi
Auditor Firm Id	171

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 70,016	$ 67,737
Prepaid expenses and other current assets	955	475
Total current assets	70,971	68,212
Other assets	90	90
Total assets	71,061	68,302
Current liabilities:
Accounts payable	44,698	15,366
Accrued expenses	19,882	3,175
Deferred revenue	4,145	1,874
Total current liabilities	68,725	20,415
Non-current liabilities:
Deferred revenue	1,018	2,342
Long-term debt	25,006
Total liabilities	94,749	22,757
Commitments and contingencies (Note 7)
Stockholders' equity (deficit):
Common stock, $0.001 par value: 225,000,000 shares authorized at December 31, 2021 and December 31, 2020; 64,027,629 and 51,626,508 shares issued and outstanding at December 31, 2021 and December 31, 2020, respectively	64	52
Additional paid-in capital	587,327	419,923
Accumulated deficit	(611,079)	(374,430)
Total stockholders' equity (deficit)	(23,688)	45,545
Total liabilities and stockholders' equity (deficit)	$ 71,061	$ 68,302

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2021	Dec. 31, 2020
Statement of Financial Position [Abstract]
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized	225,000,000	225,000,000
Common stock, shares issued	64,027,629	51,626,508
Common stock, shares outstanding	64,027,629	51,626,508

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Revenue:
Total revenue	$ 3,595	$ 312
Operating expenses:
Research and development	213,115	72,713
General and administrative	23,252	15,797
Total operating expenses	236,367	88,510
Loss from operations	(232,772)	(88,198)
Other expense:
Interest expense	(2,264)	(1,336)
Other expense, net	(1,613)	(1)
Net loss	$ (236,649)	$ (89,535)
Basic and diluted net loss per common share	$ (4.04)	$ (2.42)
Weighted average common shares outstanding used to calculate basic and diluted net loss per common share	58,533,637	36,963,030
License revenue [Member]
Revenue:
Total revenue	$ 3,595	$ 312

Consolidated Statements of Stoc

Consolidated Statements of Stockholders' Equity (Deficit) - USD ($) $ in Thousands	Common Stock [Member]	Additional Paid-In Capital [Member]	Accumulated Deficit [Member]	Total
Balances at Dec. 31, 2019	$ 22	$ 270,555	$ (284,895)	$ (14,318)
Balances (in shares) at Dec. 31, 2019	22,806,890
Issuance of common stock, net of expenses	$ 27	139,733		139,760
Issuance of common stock, net of expenses, shares	25,745,744
Issuance of common stock for conversion of debt	$ 3	4,313		4,316
Issuance of common stock for conversion of debt, shares	2,397,916
Issuance of common stock in exchange for services		302		302
Issuance of common stock in exchange for services (in shares)	45,064
Issuance of stock options for payment of compensation		180		180
Issuance of common stock for payment of compensation		78		78
Issuance of common stock for payment of compensation, shares	17,317
Issuance of warrant for services		2,070		2,070
Issuance of common stock upon option exercise		572		572
Issuance of common stock upon option exercise, shares	390,668
Issance of common stock upon warrant exercise		10		10
Issance of common stock upon warrant exercise, shares	222,909
Stock-based compensation expense		2,110		2,110
Net loss			(89,535)	(89,535)
Balances at Dec. 31, 2020	$ 52	419,923	(374,430)	45,545
Balances (in shares) at Dec. 31, 2020	51,626,508
Issuance of common stock, net of expenses	$ 12	159,903		159,915
Issuance of common stock, net of expenses, shares	11,835,104
Issuance of stock options for payment of compensation		168		168
Issuance of common stock upon option exercise		1,965		1,965
Issuance of common stock upon option exercise, shares	566,017
Stock-based compensation expense		5,368		5,368
Net loss			(236,649)	(236,649)
Balances at Dec. 31, 2021	$ 64	$ 587,327	$ (611,079)	$ (23,688)
Balances (in shares) at Dec. 31, 2021	64,027,629

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Operating activities:
Net loss	$ (236,649)	$ (89,535)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock based compensation expense	5,368	2,110
Non-cash interest expense related to debt financing	562	706
Issuance of common stock for payment of compensation		78
Issuance of common stock in exchange for services		302
Changes in operating assets and liabilities:
Prepaid expenses and other assets	(480)	(166)
Accounts payable	29,332	8,032
Accrued expenses	16,875	4,405
Deferred revenue	947	4,216
Net cash used in operating activities	(184,045)	(69,852)
Investing activities:
Purchase of intangible assets		(20)
Net cash used in investing activities		(20)
Financing activities:
Net proceeds from issuance of common stock	159,915	139,760
Proceeds from exercise of stock options	1,965	572
Net proceeds from issuance of long-term debt	24,444	10
Net proceeds from issuance of convertible notes		467
Net proceeds from issuance of PPP loan		83
Net proceeds from issuance of bridge notes		350
Payments on PPP loan		(83)
Payments on bridge notes		(2,400)
Payments on convertible notes		(518)
Payments on notes payable to vendors		(775)
Net cash provided by financing activities	186,324	137,466
Net increase in cash and cash equivalents	2,279	67,594
Cash and cash equivalents, beginning of period	67,737	143
Cash and cash equivalents, end of period	70,016	67,737
Supplemental cash flow disclosure:
Cash paid for interest	1,519	672
Supplemental disclosure of non-cash investing and financing activities:
Issuance of stock options in lieu of cash compensation	168	180
Issuance of warrants for services		2,070
Conversion of notes payable and related accrued interest and fees to common stock		$ 4,316

Organization and Description of

Organization and Description of Business	12 Months Ended
	Dec. 31, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization and Description of Business	1. Organization and Description of Business Description of the Business Humanigen, Inc. (the “Company” or “Humanigen”) was incorporated on March 15, 2000 in California and reincorporated as a Delaware corporation in September 2001. Effective August 7, 2017, the Company changed its legal name to Humanigen, Inc. The Company is a clinical stage biopharmaceutical company, developing its portfolio of proprietary Humaneered® anti-inflammatory immunology and immuno-oncology monoclonal antibodies. The Company’s proprietary, patented Humaneered technology platform is a method for converting existing antibodies (typically murine) into engineered, high-affinity human antibodies designed for therapeutic use, particularly with acute and chronic conditions. Humanigen has developed or in-licensed targets or research antibodies, typically from academic institutions, and then applied its Humaneered technology to optimize them. The Company’s lead product candidate, lenzilumab, and its other two product candidates, ifabotuzumab (“iFab”) and HGEN005, are Humaneered monoclonal antibodies. The Company’s Humaneered antibodies are closer to human antibodies than chimeric or conventionally humanized antibodies and have a high affinity for their target. In addition, the Company believes its Humaneered antibodies offer further important advantages, such as high potency, a slow off-rate and a lower likelihood to induce an inappropriate immune response or infusion related reaction. It is focusing its efforts on the development of its lead product candidate, lenzilumab. Lenzilumab is a monoclonal antibody that has been demonstrated to neutralize GM-CSF, a cytokine that the Company believes is of critical importance in the hyperinflammatory cascade, sometimes referred to as cytokine release syndrome (“CRS”) or cytokine storm, associated with COVID-19, chimeric antigen receptor T-cell (“CAR-T”) therapy and acute Graft versus Host Disease (“aGvHD”) associated with bone marrow transplants. The Company’s development programs in COVID-19, CAR-T and aGvHD are complementary in that all are focused on preventing or reducing cytokine storm in those disease states. It is possible that results observed from the Phase 3 trials in COVID-19 described below may be predictive of results in these other settings, which are also characterized by cytokine storm. The Company has completed a Phase 3 registrational trial with lenzilumab in newly hospitalized COVID-19 patients and announced positive topline data from the study known as “LIVE-AIR” in March 2021. Following completion of the LIVE-AIR study, the Company commenced a series of efforts to attain authorization to commercialize lenzilumab for use in hospitalized COVID-19 patients in the United States and other territories. The Company’s regulatory initiatives have not yet resulted in any commercial authorization. The next anticipated step in the Company’s development program for lenzilumab in COVID-19 is the release of results from the Accelerating COVID-19 Therapeutic Interventions and Vaccines-5 (“ACTIV-5”) and Big Effect Trial, in the “B” arm of the trial (“BET-B”), referred to as the ACTIV-5/BET-B trial, which is sponsored and funded by the National Institutes of Health (“NIH”). This study is evaluating lenzilumab in combination with remdesivir, compared to placebo and remdesivir, in hospitalized COVID-19 patients, as more fully described below. A retrospective analysis of the LIVE-AIR study suggested that patients under the age of 85 and with a baseline C-reactive protein level (“CRP”) below 150 mg/L (the “CRP subgroup”) appeared to derive the greatest benefit from lenzilumab; therefore, the ACTIV-5/BET-B study protocol was modified to include baseline CRP below 150 mg/L as the primary analysis population. The ACTIV-5/BET-B study has reached its target enrollment with over 400 patients enrolled that met this criterion. Topline results from ACTIV-5/BET-B are expected to be released late in the first quarter or early in the second quarter of 2022. If confirmatory of the findings of the CRP subgroup from the Company’s LIVE-AIR study, the Company plans to include the results from ACTIV-5/BET-B in an amendment to its Emergency Use Authorization (“EUA”) submission, and to include these results in a responsive submission to Medicines and Healthcare products Regulatory Agency (“MHRA”) of the United Kingdom along with certain performance process qualification (“PPQ”) data around drug product batches, in the second quarter of 2022. In addition, as a result of feedback received from representatives of European Medicines Agency (“EMA”), if the ACTIV-5/BET-B data are confirmatory of the results of the findings of the CRP subgroup from the LIVE-AIR study, the Company intends to submit a Conditional Marketing Authorization (“CMA”) for lenzilumab with an Accelerated Approval request to EMA later in 2022. See Management’s Discussion and Analysis of Financial Condition and Results of Operations included in Item 7 of this Annual Report on Form 10-K for additional information regarding the business. Liquidity and Going Concern The Consolidated Financial Statements for the years ended December 31, 2021 and 2020 were prepared on the basis of a going concern, which contemplates that the Company will be able to realize assets and discharge liabilities in the normal course of business. However, the Company has incurred net losses since its inception, and has negative operating cash flows and its total liabilities exceed total assets. These conditions raised substantial doubt about the Company’s ability to continue as a going concern. F-9 Table of Contents The Company continues to advance its efforts in support of the development of lenzilumab as a therapy for hospitalized COVID-19 patients. As of December 31, 2021, the Company had cash and cash equivalents of $70.0 million. On September 8, 2021, U.S. Food and Drug Administration (“FDA”) declined to approve the Company’s EUA for lenzilumab. As more fully described under “Item 1. Business—Manufacturing and Raw Materials.” in this Annual Report on Form 10-K, the Company has entered into agreements with several contract manufacturing organizations (“CMOs”) to provide manufacturing, fill/finish and packaging services for lenzilumab. While the Company remains committed to its ongoing efforts seeking marketing authorization for lenzilumab to treat hospitalized COVID-19 patients in the U.S., UK and other territories, the Company has amended, and in some cases canceled, certain of these agreements, some of which were contingent on EUA, in an effort to reduce its future spending on lenzilumab production until and if authorization is received in the UK, European Union (“EU”), or U.S. (See Note 7 below). These changes may limit future production of lenzilumab but because most of the Company’s manufacturing agreements required payment of upfront fees upon execution and payments against performance of the services to be provided, often over a lengthy performance period, the changes are expected to decrease the Company’s manufacturing costs beginning in 2022 Considering the Company’s current cash resources and its current and expected levels of operating expenses, which includes combined accounts payable and accrued expenses recorded in the Company’s consolidated balance sheets as of December 31, 2021 of $64.6 million, and its capital commitments of $63.4 million during 2022 (see Note 7 below),management expects to need additional capital to fund the Company’s planned operations for the next twelve months. Management may seek to raise such additional capital through public or private equity offerings, including under the Controlled Equity Offering SM

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2021
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies Reclassifications Certain prior year amounts in the Consolidated Financial Statements have been reclassified to conform to the current year's presentation. Such reclassifications had no effect on prior years’ net loss or stockholders’ equity (deficit). Basis of Presentation and Use of Estimates The accompanying Consolidated Financial Statements have been prepared in accordance with U.S. generally accepted accounting principles (“GAAP”) and include all adjustments necessary for the presentation of the Company’s consolidated financial position, results of operations and cash flows for the periods presented. The Consolidated Financial Statements include the accounts of the Company and its wholly owned subsidiaries. These financial statements have been prepared on a basis that assumes that the Company will continue as a going concern, which contemplates the realization of assets and the satisfaction of liabilities and commitments in the normal course of business. The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts and disclosures reported in the Consolidated Financial Statements and accompanying notes. Actual results could differ materially from those estimates. The Company believes judgment is involved in accounting for the determination of revenue recognition, the fair value-based measurement of stock-based compensation and accruals. The Company evaluates its estimates and assumptions as facts and circumstances dictate. As future events and their effects cannot be determined with precision, actual results could differ from these estimates and assumptions, and those differences could be material to the Consolidated Financial Statements. F-10 Table of Contents Concentration of Credit Risk Cash, cash equivalents, and marketable securities consist of financial instruments that potentially subject the Company to a concentration of credit risk in the event of a default by the related financial institution holding the securities, to the extent of the value recorded in the consolidated balance sheet. The Company invests cash that is not required for immediate operating needs primarily in highly liquid instruments with lower credit risk. The Company has established guidelines relating to the quality, diversification, and maturities of securities to enable the Company to manage its credit risk. Cash and Cash Equivalents The Company considers all highly liquid investments with an original maturity of 90 days or less at the time of purchase to be cash equivalents. Cash and cash equivalents consist of deposits with commercial banks in checking, interest-bearing and demand money market accounts. Debt Issuance Costs Debt issuance costs related to a recognized debt liability are presented on the consolidated balance sheets as a direct deduction from the carrying amount of that debt liability, consistent with debt discounts and are amortized to interest expense over the term of the related debt using the effective interest method. Research and Development Expenses Development costs incurred in the research and development of new product candidates are expensed as incurred, including expenses that may or may not be reimbursed under research and development collaboration arrangements. Research and development costs include, but are not limited to, salaries, benefits, stock-based compensation, laboratory supplies, allocated overhead, fees for professional service providers and costs associated with product development efforts, including the cost of consultants and contract manufacturing organizations (“CMOs”) that manufacture drug products for use in our preclinical studies and clinical trials as well as all other expenses associated with preclinical studies and clinical trials. The Company estimates preclinical study and clinical trial expenses based on the services performed, pursuant to contracts with research institutions and clinical research organizations that conduct and manage preclinical studies and clinical trials on its behalf. In accruing service fees, the Company estimates the time period over which services will be performed and the level of effort to be expended in each period. If the actual timing of the performance of services or the level of effort varies from the estimate, the Company will adjust the accrual accordingly. Payments made to third parties under these arrangements in advance of the receipt of the related services are recorded as prepaid expenses until the services are rendered. The Company records upfront and milestone payments made to third parties under licensing arrangements as an expense. Upfront payments are recorded when incurred and milestone payments are recorded when the specific milestone has been achieved. Revenue Recognition The Company’s revenue to date has been generated primarily through license agreements and research and development collaboration agreements. The Company recorded $3.6 million and $0.3 million for the years ending December 31, 2021 and 2020, respectively, related to the November 3, 2020 License Agreement (the “South Korea Agreement”) with KPM Tech Co., Ltd. (“KPM”) and its affiliate, Telcon RF Pharmaceutical, Inc. (“Telcon”), as further described in Note 3. Commencing January 1, 2018, the Company recognizes revenue in accordance with Financial Accounting Standards Board (“FASB”) Accounting Standards Codification (“ASC”) Topic 606 – Revenue from Contracts with Customers Revenue under technology licenses and collaborative agreements typically consists of nonrefundable and/or guaranteed license fees, collaborative research funding, and various milestone and future product royalty or profit-sharing payments. The fair value of deliverables under the arrangement may be derived using a best estimate of selling price if vendor specific objective evidence and third-party evidence is not available. Deliverables under the arrangement will be separate units of accounting if a delivered item has value to the customer on a standalone basis and if the arrangement includes a general right of return for the delivered item, delivery or performance of the undelivered item is considered probable and substantially in the Company’s control. F-11 Table of Contents The Company recognizes upfront license payments as revenue upon delivery of the license only if the license has standalone value from any undelivered performance obligations and that value can be determined. The undelivered performance obligations typically include manufacturing or development services or research and/or steering committee services. If the fair value of the undelivered performance obligations can be determined, then these obligations would be accounted for separately. If the license is not considered to have standalone value, then the license and other undelivered performance obligations would be accounted for as a single unit of accounting. In this case, the license payments and payments for performance obligations are recognized as revenue over the estimated period of when the performance obligations are performed or deferred indefinitely until the undelivered performance obligation is determined. Whenever the Company determines that an arrangement should be accounted for as a single unit of accounting, the Company determines the period over which the performance obligations will be performed, and revenue will be recognized. Revenue is recognized using a proportional performance or straight-line method. The proportional performance method is used when the level of effort required to complete performance obligations under an arrangement can be reasonably estimated. The amount of revenue recognized under the proportional performance method is determined by multiplying the total payments under the contract, excluding royalties and payments contingent upon achievement of milestones, by the ratio of the level of effort performed to date to the estimated total level of effort required to complete performance obligations under the arrangement. If the Company cannot reasonably estimate the level of effort to complete performance obligations under an arrangement, the Company recognizes revenue under the arrangement on a straight-line basis over the period the Company is expected to complete its performance obligations. Significant management judgment is required in determining the level of effort required under an arrangement and the period over which the Company is expected to complete its performance obligations under an arrangement. The Company’s collaboration agreements typically entitle the Company to additional payments upon the achievement of development, regulatory and sales performance-based milestones. If the achievement of a milestone is considered probable at the inception of the collaboration, the related milestone payment is included with other collaboration consideration, such as upfront fees and research funding, in the Company’s revenue calculation. Typically, these milestones are not considered probable at the inception of the collaboration. As such, milestones will typically be recognized in one of two ways depending on the timing of when the milestone is achieved. If the milestone is achieved during the performance period, then the Company will only recognize revenue to the extent of the proportional performance achieved at that date, or the proportion of the straight-line basis achieved at that date, and the remainder will be recorded as deferred revenue to be amortized over the remaining performance period. If the milestone is achieved after the performance period has completed and all performance obligations have been delivered, then the Company will recognize the milestone payment as revenue in its entirety in the period the milestone was achieved. See Note 3 for information on the South Korea Agreement. Leases The Company accounts for a contract as a lease when it has the right to control the asset for a period of time while obtaining substantially all of the asset's economic benefits. The Company determines if an arrangement is a lease or contains an embedded lease at inception. For arrangements that meet the definition of a lease, the Company determines the initial classification and measurement of its operating right-of-use asset and operating lease liability at the lease commencement date and thereafter if modified. The lease term includes any renewal options that the Company is reasonably assured to exercise. The present value of lease payments is determined by using the interest rate implicit in the lease, if that rate is readily determinable; otherwise, the Company uses its estimated secured incremental borrowing rate for that lease term. In addition to rent, the leases may require the Company to pay additional amounts for taxes, insurance, maintenance, and other expenses, which are generally referred to as non-lease components. The Company has elected to not separate lease and non-lease components. Rent expense is recognized on a straight-line basis over the reasonably assured lease term based on the total lease payments and is included in operating expenses in the consolidated statements of operations. The Company has made an accounting policy election to not recognize short-term leases, or leases that have a lease term of 12 months or less at commencement date, within its consolidated balance sheets and to recognize those lease payments in the consolidated statements of operations on a straight-line basis over the lease term. Stock-Based Compensation Expense The Company measures stock-based compensation expense for stock awards at the grant date, based on the fair value-based measurement of the award, and the expense is recorded over the related service period, generally the vesting period, net of estimated forfeitures. The Company calculates the fair value-based measurement of stock options using the Black-Scholes valuation model and the simplified method and recognizes expense using the straight-line attribution approach. F-12 Table of Contents Income Taxes The Company accounts for income taxes under an asset-and-liability approach. Deferred income taxes reflect the impact of temporary differences between assets and liabilities recognized for tax and financial reporting purposes measured by applying enacted tax rates and laws that will be in effect when the differences are expected to reverse, net operating loss carryforwards and tax credits. Valuation allowances are provided when necessary to reduce net deferred tax assets to an amount that is more likely than not to be realized. The Company’s policy is to include interest and penalties related to unrecognized tax benefits within the Company’s provision for income taxes. Net Loss Per Common Share Basic net loss per common share is calculated by dividing the net loss attributable to common stockholders by the weighted-average number of common shares outstanding during the period, without consideration for potentially dilutive securities. Diluted net loss per share is computed by dividing the net loss attributable to common stockholders by the weighted-average number of common shares and potentially dilutive securities outstanding for the period determined using the treasury-stock and if-converted methods. For purposes of the diluted net loss per share calculation, stock options, common stock warrants and convertible debt are considered to be potentially dilutive securities but are excluded from the calculation of diluted net loss per share because their effect would be anti-dilutive and therefore, basic and diluted net loss per share were the same for all periods presented. The Company’s potential dilutive securities, which include stock options, warrants and convertible debt have been excluded from the computation of diluted net loss per share as the effect would be to reduce the net loss per common share and be antidilutive. Therefore, the denominator used to calculate both basic and diluted net loss per common share is the same in all periods presented. The following shares subject to outstanding potentially dilutive securities have been excluded from the computations of diluted net loss per common share as the effect of including such securities would be antidilutive: As of December 31, 2021 2020 Options to purchase common stock 4,429,906 3,728,149 Warrants to purchase common stock 31,238 51,238 Convertible debt 510,986 - 4,972,130 3,779,387 Segment Reporting The Company determines its segment reporting based upon the way the business is organized for making operating decisions and assessing performance. The Company operates in only one segment, which is related to the development of pharmaceutical products. Recent Accounting Pronouncements In December 2019, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2019-12, Simplifying the Accounting for Income Taxes. ASU No. 2019-12 eliminates certain exceptions related to the approach for intra-period tax allocation, the methodology for calculating income taxes in an interim period and the recognition of deferred tax liabilities for outside basis differences. It also clarifies and simplifies other aspects of the accounting for income taxes. ASU 2019-12 is effective for fiscal years beginning after December 15, 2020, and interim periods within those fiscal years. The Company adopted ASU No. 2019-12 on January 1, 2021, which did not have any impact to the Company’s Consolidated Financial Statements. In August 2020, the FASB issued ASU No. 2020-06, “Accounting for Convertible Instruments and Contracts in an Entity’s Own Equity”, as part of its overall simplification initiative to reduce costs and complexity of applying accounting standards while maintaining or improving the usefulness of the information provided to users of financial statements. Among other changes, the new guidance removes from U.S. GAAP, separation models for convertible debt that require the convertible debt to be separated into a debt and equity component, unless the conversion feature is required to be bifurcated and accounted for as a derivative or the debt is issued at a substantial premium. As a result, after adopting the guidance, entities will no longer separately present such embedded conversion features in equity and will instead account for the convertible debt wholly as debt. The new guidance also requires use of the “if-converted” method when calculating the dilutive impact of convertible debt on earnings per share, which is consistent with the Company’s current accounting treatment under the current guidance. The guidance is effective for the Company’s financial statements issued for fiscal years beginning after December 15, 2023, and interim periods within those fiscal years, with early adoption permitted, but only at the beginning of the fiscal year. The Company early adopted the new guidance on January 1, 2021, using the modified retrospective approach. The adoption did not have any impact to the Company’s Consolidated Financial Statements.

License Revenue

License Revenue	12 Months Ended
	Dec. 31, 2021
License Revenue
License Revenue	3. License Revenue On November 3, 2020, the Company entered into the South Korea Agreement with KPM and Telcon (together, the “Licensee”). Pursuant to the South Korea Agreement, among other things, the Company granted the Licensee a license under certain patents and other intellectual property to develop and commercialize the Company’s lead product candidate, lenzilumab, for treatment of COVID-19 pneumonia, in South Korea and the Philippines (the “Territory”), subject to certain reservations and limitations. The Licensee will be responsible for gaining regulatory approval for, and subsequent commercialization of, lenzilumab in the Territory. As consideration for the license, the Licensee has agreed to pay the Company (i) an up-front license fee of $6.0 million (or $4.5 million net of withholding taxes and other fees and royalties), payable promptly following the execution of the License Agreement, which was received in the fourth quarter of 2020, (ii) up to an aggregate of $14.0 million in two payments based on achievement by the Company of two specified milestones in the U.S., of which the first milestone was met in the first quarter of 2021 and $6.0 million (or $4.5 million net of withholding taxes and other fees and royalties) was received in the second quarter of 2021, and (iii) subsequent to the receipt by the Licensee of the requisite regulatory approvals, double-digit royalties on the net sales of lenzilumab in South Korea and the Philippines. The Licensee has agreed to certain development and commercial performance obligations. It is expected that the Company will supply lenzilumab to the Licensee for a minimum of 7.5 years at a cost-plus basis from an existing or future manufacturer. The Licensee has agreed to certain minimum purchases of lenzilumab on an annual basis. The Company assessed the South Korea Agreement in accordance with ASC 606 and ASC 808 – Collaborative Arrangements The Company has concluded that the nature of its promise is to stand ready to provide Research and Development Services as needed during the Performance Period (as defined below). The Company has further concluded that for all of the increments of time during the Performance Period its promise of standing ready to provide the Services is substantially the same. While the specific tasks performed during each increment of time will vary, the nature of the overall promise to provide the Services remains the same throughout the Performance Period. Since the provision of the license and the Services are considered a single performance obligation, the $4.5 million upfront payment ($6.0 million net of withholding taxes and other fees and royalties) is being recognized as revenue ratably over the 29-month period through March of 2023 (the “Performance Period”), the expected period over which the Company conservatively expects the Services to be performed with approval in the Territory expected by the end of March 2023. In addition, since the milestone was achieved during the performance period, the Company recognized revenue to the extent of the proportion of the straight-line basis achieved as of the first quarter of 2021, with the remainder recorded as deferred revenue to be amortized over the remaining Performance Period. Therefore, in the years ended December 21, 2021 and 2020, the Company has recognized license revenue totaling approximately $3.6 million and $0.3 million, respectively. Licensee’s purchases of lenzilumab for development purposes or for commercial requirements, represent options under the agreement and revenues will therefore be recognized when control of the product is transferred to Licensee. Contract Liabilities A contract liability of $5.2 million was recorded on the Consolidated Balance Sheets as deferred revenue as of December 31, 2021 related to the South Korea agreement. There were no contract asset or deferred contract acquisition costs as of December 31, 2021 associated with the South Korea agreement. F-14 Table of Contents The following table presents changes in the Company’s contract liability for the years ended December 31, 2021 and 2020 (in thousands): Balance at January 1, 2020 $ - Additions (1) 4,528 Deductions for performance obligations satisfied: In current period (312 ) Balance at December 31, 2020 4,216 Additions (2) 4,542 Deductions for performance obligations satisfied: In current period (1,721 ) In prior period (1,874 ) Balance at December 31, 2021 $ 5,163 _______________ ​ (1) ​ (2)

Accrued Expenses

Accrued Expenses	12 Months Ended
	Dec. 31, 2021
Accrued Liabilities, Current [Abstract]
Accrued Expenses	4. Accrued Expenses Accrued expenses consist of the following (in thousands): As of December 31, 2021 2020 Accrued contract manufacturing-related $ 16,174 $ - Accrued milestone and royalties 2,736 2,368 Accrued clinical trial-related 160 - Accrued compensation-related 44 530 Accrued other 768 277 $ 19,882 $ 3,175

Debt

Debt	12 Months Ended
	Dec. 31, 2021
Disclosure Text Block [Abstract]
Debt	5. Debt Secured Term Loan Facility On March 10, 2021, the Company executed a Loan and Security Agreement with Hercules Capital as agent for its affiliates serving as lenders thereunder (the “Term Loan”). The Term Loan provides a loan in the aggregate principal amount of up to $80.0 million, in three tranches. On March 29, 2021, the Company drew the initial $25.0 million tranche under the Term Loan. After giving effect to payment of fees and expenses associated with the draw, the Company received net proceeds of approximately $24.4 million. The Company is no longer entitled to draw the second tranche, which was to be in the amount of $35.0 million or $25.0 million, as it did not receive EUA for lenzilumab for the treatment of hospitalized patients with COVID-19 pneumonia by September 15, 2021. The Company may become entitled to draw another $20.0 million under the Term Loan through June 15, 2022, at the discretion of Hercules if the Company requests additional funding in support of the Company’s strategic initiatives, although there can be no assurances that Hercules would agree to provide such additional funding. The Company will be required to repay amounts borrowed by March 1, 2025, subject to a one-year extension option that it may exercise if it has received FDA approval of a BLA for the use of lenzilumab for the treatment of hospitalized patients with COVID-19 pneumonia, and the FDA-authorized label for lenzilumab is generally consistent with that sought in the Company’s BLA filing, and the Company has paid Hercules certain fees and expenses associated with the extension. Amounts drawn bear interest at a floating rate equal to the greater of either (i) 8.75% plus the prime rate as reported in The Wall Street Journal minus 3.25%, or (ii) 8.75% (such greater amount, the “Base Interest Rate”). Subject to there not having occurred any default or event of default under the loan agreement, the Base Interest Rate will be reduced by 25 basis points upon the occurrence of each of the first three of the four following events to occur: • if the Company achieves the protocol-specified primary efficacy endpoint for the pivotal Phase 3 study of lenzilumab for COVID-19, (clinicaltrials.gov identifier NCT04351152), and receives EUA for the use of lenzilumab for the treatment of hospitalized patients with COVID-19 pneumonia; F-15 Table of Contents • if the Company achieves product revenue from lenzilumab that is invoiced and/or recognized as revenue (as determined in accordance with GAAP) solely from the sale of lenzilumab (“Net Lenzilumab Product Revenue”) of at least $100.0 million; • if the Company achieves Net Lenzilumab Product Revenue of at least $250.0 million; and • if the Company achieves Net Lenzilumab Product Revenue of at least $350.0 million. No principal payments will be due during an interest-only period, commencing on the initial borrowing date and continuing to April 1, 2023, subject to extension to April 1, 2024, and potentially October 1, 2024, under certain conditions. Following the interest-only period, the outstanding balance of the loan will be required to be repaid monthly, continuing through the maturity date. The Company may prepay amounts drawn under the agreement in full prior to the maturity date then in effect, subject to payment of prepayment charges equal to: • 2.0% of the amounts borrowed, if the prepayment occurs on or prior to March 29, 2022; • 1.5% of the amounts borrowed, if the prepayment occurs after March 29, 2022 and before March 29, 2023; and • 1.0% of the amounts borrowed, if the prepayment occurs after March 29, 2023 and before March 29, 2024. In addition, on the earliest to occur of (i) the maturity date, (ii) the date the Company prepays the outstanding principal amount of the Term Loan, or (iii) the date the outstanding principal amount of the Term Loan otherwise becomes due, the Company will owe Hercules an end of term (“EOT”) charge equal to 6.75% of the aggregate amount of the Term Loan funded by Hercules. As a condition to obtaining the Term Loan, the Company granted Hercules a security interest in substantially all of its assets and personal property not otherwise subject to existing or permitted liens. In addition, the Term Loan contains customary representations and warranties and events of default for a term loan facility of this size and type. Under the Term Loan, the Company also agreed to comply with certain customary affirmative and negative covenants that become effective upon the initial draw of the first tranche, including covenants to: • maintain $10.0 million unrestricted cash; • comply with certain requirements to provide Hercules with financial information and other rights to inspect the Company’s books and records and the collateral for the Term Loan; • refrain from incurring debt that is not expressly subordinated to the Term Loan; “Rule 144A-style” convertible notes in aggregate principal amount up to $250.0 million; and other permitted indebtedness; • refrain from granting (or permitting to exist) liens on the Company’s assets and properties, other than certain permitted liens, including in respect of its patents and other intellectual property; • refrain from making certain investments, other than permitted acquisitions and certain other permitted investments; • refrain from repurchasing the Company’s stock or paying dividends, subject to limited exceptions; • refrain from transferring any material portion of its assets; and • refrain from entering into any merger or consolidation in which the Company is not the surviving entity. All of these covenants will not apply upon repayment of any borrowings under the Term Loan. Certain of the baskets for permitted investments and other exceptions to the covenants described above have increased because the Company has raised more than $100.0 million in unrestricted net cash proceeds from one or more bona fide equity financings prior to March 31, 2022. (See Note 8 below for information relating to the Company’s equity financings in 2021 in this regard.) Further, the covenants in the Term Loan will not prohibit the Company from pursuing its strategy of entering into out-bound license agreements for lenzilumab that may be exclusive as to specific geographic regions outside the U.S., nor will the covenants prohibit the Company from entering into co-development or co-promotion or commercialization agreements relating to lenzilumab, so long as such agreements generally are negotiated on arm’s length and commercially reasonable terms. While the Term Loan is outstanding, the lenders will have the right to convert a portion of the principal amount outstanding under the Term Loan (ranging from $5.0 million to $10.0 million in the aggregate) into shares of the Company’s common stock at a conversion price equal to $19.57 per share, subject to customary anti-dilution adjustments. F-16 Table of Contents The following table summarizes the outstanding future payments of principal and interest associated with the Company’s Term Loan as of December 31, 2021 (in thousands): 2022 $ 2,218 2023 10,800 2024 13,671 2025 5,153 Total payments 31,842 Less amount representing interest (5,155 ) Notes payable, gross 26,687 Less: Unamortized portion of EOT charge (1,264 ) Less: Unamortized discount on notes payable (159 ) Less: Unamortized debt issuance costs (258 ) Long-term debt 25,006 Less current portion - Long-term debt, net of current portion $ 25,006 Interest expense related to the Term Loan, for the year ended December 31, 2021 was approximately $2.3 million and the effective interest rate was 9.0%. Notes Payable to Vendors On June 30, 2016, the Company issued promissory notes in an aggregate principal amount of approximately $1.2 million to certain claimants in accordance with the Company’s Plan of Reorganization (the “Plan”) filed with the United States Bankruptcy Court for the District of Delaware (the “Bankruptcy Court”) (Case No. 15-12628 (LSS) (the “Bankruptcy Case”) which became effective June 30, 2016, at which time the Company emerged from its Chapter 11 bankruptcy proceedings. The notes were unsecured, accrued interest at 10% per annum and became due and payable in full, including principal and accrued interest on June 30, 2019. In July and August, 2019, following the receipt of proceeds from the 2019 Bridge Notes, the Company used approximately $0.5 million of the proceeds to retire a portion of these notes, including accrued interest. In June and July 2020, the Company used the proceeds from the Private Placement (as defined below) to repay the remaining outstanding principal including accrued and unpaid interest on these notes and the notes were extinguished. As of December 31, 2020, all the notes had been repaid. Convertible Notes 2018 Convertible Notes Commencing September 19, 2018, the Company delivered a series of convertible promissory notes (the “2018 Notes”) evidencing an aggregate of $2.5 million of loans made to the Company by six different lenders, including an affiliate of Black Horse Capital, L.P. (“BHC”), the Company’s controlling stockholder at the time. The 2018 Notes accrued interest at a rate of 7% per annum and, in general, were set to mature twenty-four months from the date the 2018 Notes were signed. The Company used the proceeds from the 2018 Notes for working capital. The 2018 Notes were convertible into equity securities of the Company in three different scenarios, including if the Company sold its equity securities on or before the date of repayment of the 2018 Notes in any financing transaction that resulted in gross proceeds to the Company of less than $10.0 million (a “Non-Qualified Financing”). In connection with a Non-Qualified Financing, the noteholders were able to convert their remaining 2018 Notes into either (i) such equity securities as the noteholder would acquire if the principal and accrued but unpaid interest thereon (the “Conversion Amount”) were invested directly in the financing on the same terms and conditions as given to the financing investors in the Non-Qualified Financing, or (ii) common stock at a conversion price equal to $2.25 per share (subject to ratable adjustment for any stock split, stock dividend, stock combination or other recapitalization occurring subsequent to the date of the Notes). The Company’s sales of shares pursuant to the ELOC Purchase Agreement with Lincoln Park constituted a Non-Qualified Financing. Commencing on April 2, 2020, the holders of the 2018 Notes notified the Company of their exercise of their conversion rights under the 2018 Notes. See “2019 Convertible Notes” for additional information regarding the conversion of 2018 Notes by the holders. Interest expense recorded during the year ended December 31, 2020 related to the 2018 Notes was approximately $0.8 million. F-17 Table of Contents 2019 Convertible Notes Commencing on April 23, 2019, the Company delivered a series of convertible promissory notes (the “2019 Notes” and together with the 2018 Notes, the “Convertible Notes”) evidencing an aggregate of $1.3 million of loans made to the Company. The 2019 Notes accrued interest at a rate of 7.5% per annum and, in general, were set to mature twenty-four months from the date the 2019 Notes were signed. The Company used the proceeds from the 2019 Notes for working capital. The 2019 Notes were convertible into equity securities of the Company in four different scenarios, including if the Company sold its equity securities on or before the date of repayment of the 2019 Notes in any financing transaction that resulted in gross proceeds to the Company of less than $10.0 million (a “Non-Qualified Financing”). In connection with a Non-Qualified Financing, the noteholders were able to convert their remaining 2019 Notes into either (i) such equity securities as the noteholder would acquire if the Conversion Amount were invested directly in the financing on the same terms and conditions as given to the financing investors in the Non-Qualified Financing, or (ii) common stock at a conversion price equal to $6.25 per share (subject to ratable adjustment for any stock split, stock dividend, stock combination or other recapitalization occurring subsequent to the date of the 2019 Notes). The Company’s sales of shares pursuant to the ELOC Purchase Agreement with LPC constituted a Non-Qualified Financing. Commencing on April 2, 2020, holders of the Convertible Notes, including Cheval, an affiliate of BHC, the Company’s controlling stockholder at the time, notified the Company of their exercise of their conversion rights under the Convertible Notes. Pursuant to the exemption from registration afforded by Section 3(a)(9) under the Securities Act, the Company issued an aggregate of 2,397,916 shares of its common stock upon the conversion of $4.3 million in aggregate principal and interest on the Convertible Notes that were converted, which obligations were retired. Of these, the Company issued 316,666 shares to Cheval. Dr. Dale Chappell, who was serving as the Company’s ex-officio chief scientific officer at the time and currently serves as its Chief Scientific Officer, controls BHC and reports beneficial ownership of all shares held by it and its affiliates, including Cheval. After giving effect to the shares issued upon such conversions, no convertible notes issued in 2018 or 2019 were outstanding as of December 31, 2020. Interest expense related to the 2019 Notes, recorded during the year ended December 31, 2020, was approximately $0.2 million. The Advance Notes, the 2018 Notes and the 2019 Notes had an optional voluntary conversion feature in which the holder could convert the notes in the Company’s common stock at maturity at a conversion rate of $2.25 per share for the Advance Notes and the 2018 Notes and at a conversion rate of $6.25 for the 2019 Notes. The intrinsic value of this beneficial conversion feature was $1.8 million upon the issuance of the Advance Notes, the 2018 Notes and the 2019 Notes and was recorded as additional paid-in capital and as a debt discount which was accreted to interest expense over the term of the Advance Notes, the 2018 Notes and the 2019 Notes. Interest expense included debt discount amortization of $0.8 million for the year ended December 31, 2020. The Company evaluated the embedded features within the Advance Notes, the 2018 Notes and the 2019 Notes to determine if the embedded features are required to be bifurcated and recognized as derivative instruments. The Company determined that the Advance Notes, the 2018 Notes and the 2019 Notes contain contingent beneficial conversion features (“CBCF”) that allow or require the holder to convert the Advance Notes, the 2018 Notes and the 2019 Notes, as applicable, to Company common stock at a conversion rate of $2.25 per share for the Advance Notes and the 2018 Notes and $6.25 for the 2019 Notes, but did not contain embedded features requiring bifurcation and recognition as derivative instruments. Upon the occurrence of a CBCF that results in conversion of the Advance Notes, the 2018 Notes or the 2019 Notes to Company common stock, the remaining unamortized discount will be charged to interest expense. Upon conversion of the Advance Notes on May 30, 2019, the remaining unamortized discount was charged to interest expense. Upon the conversion of the Convertible Notes in April 2020, the remaining related unamortized discount was charged to interest expense. 2020 Convertible Redeemable Notes On March 13, 2020 and March 19, 2020 (the “Issuance Dates”), the Company delivered two convertible redeemable promissory notes (the “2020 Notes”) evidencing loans with an aggregate principal amount of $518,333 made to the Company. The 2020 Notes accrued interest at a rate of 7.0% per annum and were set to mature on March 13, 2021 and March 19, 2021, respectively. The 2020 Notes contained an original issue discount of $33,000 and $18,833, respectively. The Company used the proceeds from the 2020 Notes for working capital. The notes could be redeemed by the Company at any time before the 270 th F-18 Table of Contents The Company evaluated the embedded features within the 2020 Notes and determined that the embedded features are required to be bifurcated and recognized as stand-alone derivative instruments. The variable-share settlement features within the 2020 Notes qualify as redemption features and meet the net settlement criterion for qualification as a stand-alone derivative. In determining the fair value of the bifurcated derivative, the Company evaluated the likelihood of conversion of the 2020 Notes to Company stock. As the Company believed it would have adequate funding prior to the six-month anniversary of the 2020 Notes, the first conversion option for the holders of the 2020 Notes, and it had the intent to either begin making amortizing payments or to pay off the 2020 Notes in their entirety prior to that date, the fair value was determined to be $0. The original issue discount was accreted to interest expense and the remaining balance was charged to interest expense upon payoff. Interest expense related to the 2020 Notes, recorded during the year ended December 31, 2020, was approximately $0.2 million. Interest expense includes the original issue discount amortization of approximately $0.1 million for the year ended December 31, 2020. Bridge Notes On June 28, 2019, the Company issued three short-term, secured bridge notes (the “June Bridge Notes”) evidencing an aggregate of $1.7 million of loans made to the Company by three parties: Cheval, an affiliate of BHC, the Company’s controlling stockholder at the time, lent $0.75 million; Nomis Bay LTD, the Company’s second largest stockholder, lent $0.75 million; and Dr. Cameron Durrant, the Company’s Chief Executive Officer and Chairman of the Board of Directors (the “Board”), lent $0.2 million. The proceeds from the June Bridge Notes were used to satisfy a portion of the unsecured obligations incurred in connection with the Company’s emergence from bankruptcy in 2016 and for working capital and general corporate purposes. The June Bridge Notes accrued interest at a rate of 7.0% per annum and after giving effect to multiple extensions, were set to mature on December 31, 2020. The June Bridge Notes could become due and payable at such earlier time as the Company raised more than $3.0 million in a bona fide financing transaction or upon a change in control. Accordingly, the June Bridge Notes were repaid in June 2020 with proceeds from the Private Placement, and the June Bridge Notes were extinguished. On November 12, 2019, the Company issued two short-term, secured bridge notes (the “November Bridge Notes” and together with the June Bridge Notes, the “2019 Bridge Notes”) evidencing an aggregate of $0.35 million of loans made to the Company by two parties: Cheval, an affiliate of BHC, the Company’s controlling stockholder at the time, lent $0.25 million; and Dr. Cameron Durrant, the Company’s Chief Executive Officer and Chairman of its Board, lent $0.1 million. The proceeds from the November Bridge Notes were used for working capital and general corporate purposes. The November Bridge Notes ranked on par with the June Bridge Notes and possessed other terms and conditions substantially consistent with those notes. The November Bridge Notes accrued interest at a rate of 7.0% per annum and after giving effect to multiple extensions, were set to mature on December 31, 2020. The November Bridge Notes could become due and payable at such earlier time as the Company raised more than $3.0 million in a bona fide financing transaction or upon a change in control. Accordingly, the November Bridge Notes were repaid in June 2020 with proceeds from the Private Placement. In April 2020, the Company issued two short-term, secured bridge notes (the “April Bridge Notes” and together with the June Bridge Notes and the November Bridge Notes, the “Bridge Notes”) evidencing an aggregate of $0.35 million of loans made to the Company: Cheval, an affiliate of BHC, the Company’s controlling stockholder at the time, loaned $0.1 million, and Nomis Bay, the Company’s second largest stockholder, loaned $0.25 million. The proceeds from the April Bridge Notes were used for working capital and general corporate purposes. The April Bridge Notes ranked on par with the June Bridge Notes and the November Bridge Notes and possessed other terms and conditions substantially consistent with them. The notes accrued interest at a rate of 7.0% per annum and were set to mature on December 31, 2020. The April Bridge Notes could become due and payable at such earlier time as the Company raised more than $10.0 million in a bona fide financing transaction or upon a change in control. Accordingly, these April Bridge Notes were repaid in June 2020 with proceeds from the Private Placement, and these bridge notes were extinguished. The Bridge Notes were secured by a lien on substantially all the Company’s assets, which liens have been released. Interest expense related to the Bridge Notes, recorded during the year ended December 31, 2020, was approximately $0.1 million.

Warrants to Purchase Common Sto

Warrants to Purchase Common Stock	12 Months Ended
	Dec. 31, 2021
Warrants to Purchase Common Stock
Warrants to Purchase Common Stock	6. Warrants to Purchase Common Stock On June 19, 2013, the Company issued a warrant to purchase up to an aggregate of 1,238 shares of common stock at an exercise price of $484.80 per share. The warrant expires on the tenth anniversary of its issuance date. As of December 31, 2021, these warrants were fully vested and unexercised. On December 4, 2015, the Company issued a warrant to purchase up to an aggregate of 25,000 shares of common stock at an exercise price of $146.60 per share. The warrant expired on December 4, 2020. F-19 Table of Contents On June 30, 2016, the Company and Savant Neglected Diseases, LLC (“Savant”) entered into an Agreement for the Manufacture, Development and Commercialization of Benznidazole for Human Use (the “MDC Agreement”), pursuant to which the Company acquired certain worldwide rights relating to benznidazole. In connection with the MDC Agreement, also on June 30, 2016, the Company issued to Savant a five-year warrant (the “Savant Warrant”) to purchase 40,000 shares of the Company’s Common Stock, at an exercise price of $11.25 per share, subject to adjustment. The Savant Warrant was exercisable for 25% of the shares immediately and exercisable for the remaining shares upon reaching certain regulatory related milestones. In addition, pursuant to the MDC Agreement, the Company had granted Savant certain “piggyback” registration rights for the shares issuable under the Savant Warrant. On June 30, 2020, Savant exercised 20,000 warrants in a cashless exercise resulting in 10,909 shares being issued to Savant in July 2020. The remaining unvested warrants for an aggregate of up to 20,000 shares expired on June 30, 2021. On April 22, 2020, in connection with investor relation services, the Company issued two warrants to purchase up to an aggregate of 8,000 shares of common stock at an exercise price of $0.05 per share. The warrants were to vest upon either a change of control, as defined in the warrant agreement, an uplisting to a national securities exchange, or eight years from the issuance date and were to expire two years after full vesting. On September 18, 2020, the Company’s common stock commenced trading on the Nasdaq Capital Market and on the same day the warrants became vested and were exercised for proceeds of $400. On May 20, 2020, in connection with investor relation services, the Company issued a warrant to purchase up to an aggregate of 4,000 shares of common stock at an exercise price of $0.05 per share. The warrants were to vest upon either a change of control, as defined in the warrant agreement, an uplisting to a national securities exchange, or eight years from the issuance date and were to expire two years after full vesting. On September 18, 2020, the Company’s common stock commenced trading on the Nasdaq Capital Market and on the same day the warrants became vested and were exercised for proceeds of $200. On May 20, 2020, in connection with manufacturing consulting services, the Company issued a warrant to purchase up to an aggregate of 30,000 shares of common stock at an exercise price of $4.30 per share. The warrants were fully vested on the date of issue and expire ten years from the issuance date. These warrants remained unexercised as of December 31, 2021. On September 14, 2020, in connection with investor relation services, the Company issued three warrants to purchase up to an aggregate of 200,000 shares of common stock at an exercise price of $0.05 per share. The warrants were to vest upon either a change of control, as defined in the warrant agreement, an uplisting to a national securities exchange, or eight years from the issuance date and were to expire two years after full vesting. On September 18, 2020, the Company’s common stock commenced trading on the Nasdaq Capital Market and on the same day the warrants became vested and were exercised for proceeds of $10,000.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2021
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	7. Commitments and Contingencies Eversana Agreement On January 10, 2021, the Company announced that it had entered into a master services agreement (the “Eversana Agreement”) with Eversana Life Science Services, LLC (“Eversana”) pursuant to which Eversana will provide the Company multiple services from its integrated commercial platform in preparation for the potential commercialization of lenzilumab. Under the Eversana Agreement, Eversana will provide the Company with services in connection with the potential launch of lenzilumab. Eversana services during 2021 have comprised marketing, market access, consulting, field solutions, field operations, health economics and medical affairs. Additional services may be negotiated by the parties and set forth in statements of work delivered in accordance with the Eversana Agreement. On September 21, 2021, the Company notified Eversana that due to the EUA status in the U.S., it was terminating the initial statement of work related to commercialization support of lenzilumab for the treatment of COVID-19 in the United States. Eversana is disputing the termination notice and has requested payment of approximately $4.0 million it has asserted the Company owes for services rendered from April 1, 2021 to September 30, 2021. The Company has disputed this assertion and is working to resolve this dispute. The Eversana Agreement provides for a one-year term and will renew for subsequent one-year terms unless either party provides a notice of non-renewal. After the first year, the Company may terminate the Eversana Agreement upon advance written notice to Eversana. The Eversana Agreement contains customary provisions allowing either party to terminate the Eversana Agreement as a result of certain changes in law and material breaches and certain insolvency events by or relating to the other party. The Eversana Agreement imposes customary mutual obligations on the parties to protect and not disclose the confidential information and intellectual property of the other, and contains insurance, non-solicitation, indemnification and limitation of liability provisions customary for service contracts of this type. F-20 Table of Contents Manufacturing Agreements The Company has entered into agreements with several CMOs to manufacture bulk drug substance (“BDS”) and fill/finish/drug product (“DP”) for lenzilumab for a potential launch of lenzilumab in anticipation of an EUA or CMA in 2021. The Company has also entered into agreements for packaging of the drug. These agreements represent large commitments, including upfront amounts prior to commencement of manufacturing and progress payments through the course of the manufacturing process and include payments for technology transfer. Since September 9, 2021, the Company has amended, and in some cases canceled, certain of these agreements, some of which were contingent on EUA, in an effort to reduce its future spending on lenzilumab production until and if authorization is received in the UK, EU, or U.S. These changes may limit future production of lenzilumab but because most of the Company’s manufacturing agreements required payment of upfront fees upon execution and payments against performance of the services to be provided, often over a lengthy performance period, the changes are expected to decrease the Company’s manufacturing costs beginning in 2022. In addition, certain of the Company’s CMOs have been unsuccessful in their efforts to manufacture some batches of lenzilumab to the Company’s specifications for various reasons. The Company is working with these CMOs to determine if batches of BDS manufactured by them will be usable in the future or, if not, whether other financial recompense will be offered to the Company. As of December 31, 2021, the Company estimates that its commitments remaining to be incurred under these agreements are approximately $63.4 million for 2022, $4.6 million for 2023, and $7.4 million thereafter. Certain of these commitments and amounts accrued at year-end are in dispute and the Company intends to defer these payments, negotiate lower amounts or seek legal recourse for the amounts in question. Operating Leases During a portion of 2020, the Company sub-leased office space under a short-term lease in Burlingame, California. The sub-lease initial term expired on March 31, 2020 and was renewed until September 1, 2020. On September 1, 2020, the Company entered into a one-year lease for a small office in the same building in Burlingame, California for $1,200 per month which expired on August 31, 2021. On September 1, 2021, the Company entered into a new one-year lease with one-month free rent for a small office in the same building in Burlingame, California for $1,200 per month which will expire on September 30, 2022. Management determined the lease term for each of the subleases and leases to be less than 12 months, including renewals, and therefore did not record a right-of-use asset and corresponding liability under the short-term lease recognition exemption. Lease costs for the years ended December 31, 2021 and 2020 totaled approximately $14 thousand and $3 thousand, respectively, and are included in the Consolidated Statements of Operations. As of December 31, 2021, the Company had future minimum lease payments of approximately $11 thousand. Indemnification The Company has certain agreements with service providers with which it does business that contain indemnification provisions pursuant to which the Company typically agrees to indemnify the party against certain types of third-party claims. The Company accrues for known indemnification issues when a loss is probable and can be reasonably estimated. The Company would also accrue for estimated incurred but unidentified indemnification issues based on historical activity. As the Company has not incurred any indemnification losses to date, there were no accruals for or expenses related to indemnification issues for any period presented.

Stockholders' Equity

Stockholders' Equity	12 Months Ended
	Dec. 31, 2021
Stockholders' Equity Note [Abstract]
Stockholders' Equity	8. Stockholders’ Equity Reverse Stock Split Effective as of 4:30 p.m. Eastern Time on September 11, 2020 (the “Effective Time”), the Company amended its charter to effect a reverse stock split at a ratio of 1-for-5 (the “Split Ratio”). No fractional shares were issued in connection with the reverse stock split. Stockholders of record otherwise entitled to receive fractional shares of common stock received cash (without interest or deduction) in lieu of such fractional share interests. The reverse stock split reduced the total number of shares of the Company’s common stock outstanding as of the Effective Time from approximately 210.9 million shares to approximately 42.2 million shares. The par value per share and other terms of the Company’s common stock were not affected by the reverse stock split, and the number of authorized shares of the Company’s common stock remained at 225,000,000. The reverse stock split resulted in a proportionate adjustment in the number of shares reserved for issuance under the 2020 Equity Plan, such that a total of 7,000,000 shares of the Company’s common stock were reserved for issuance under the 2020 Equity Plan following the Effective Time. In addition, proportionate adjustments were made to the number of shares covered by, and the exercise price applicable to, each outstanding stock option award under the 2012 Equity Plan and outstanding warrants issued by the Company, in each case to give effect to the Split Ratio and the reverse stock split. F-21 Table of Contents The reverse stock split was accounted for retroactively and is reflected in the Company’s common stock, stock option and warrant activity as of and during the year ended December 31, 2020. Unless stated otherwise, all share data and per share data in this Annual Report on Form 10-K have been adjusted, as appropriate, to reflect the reverse stock split. 2020 Private Placement On June 1, 2020, the Company entered into a securities purchase agreement (the “Purchase Agreement”) with certain accredited investors (the “Investors”) to complete a private placement of the Company’s common stock (the “Private Placement”). The closing of the Private Placement occurred on June 2, 2020 (the “Closing Date”). At the closing, the Company issued and sold 16,505,743 shares of its common stock (the “Shares”) at a purchase price of $4.35 per share, for aggregate gross proceeds of approximately $71.8 million. The Company used a portion of the proceeds to retire certain indebtedness, as further described in Note 5. See Note 11 for information regarding two complaints filed against the Company in connection with the Private Placement. On the Closing Date, the Company and the Investors also entered into a registration rights agreement (the “Registration Rights Agreement”) pursuant to which the Company agreed to prepare and file a registration statement (the “Resale Registration Statement”) for the resale of the Shares with the Securities and Exchange Commission. Subject to certain limitations and an overall cap, the Company may be required to pay liquidated damages to the investors at a rate of 2% of the invested capital for each occurrence (and continuation for 30 consecutive days thereafter) of a breach by the Company of certain of its obligations under the Registration Rights Agreement. The Purchase Agreement also required that the Company use its commercially reasonable efforts to achieve a listing of the Common Stock on a national securities exchange, subject to certain limitations set forth in the Purchase Agreement. On July 6, 2020, the Company applied to have its common stock approved for listing on the Nasdaq Capital Market. On September 18, 2020, the Company’s common stock commenced trading on the Nasdaq Capital Market under the symbol “HGEN.” 2020 Underwritten Public Offering On September 17, 2020, the Company entered into an underwriting agreement (the “Underwriting Agreement”) with J.P. Morgan Securities LLC and Jefferies LLC, as representatives of the several underwriters, in connection with the public offering of 8,000,000 of the Company’s shares of common stock. Pursuant to the Underwriting Agreement, the Company granted the underwriters a 30-day option to purchase an additional 1,200,000 shares of common stock, which option was exercised in full by the underwriters on September 18, 2020. As a result of the pricing of the public offering, the Company’s common stock commenced trading on the Nasdaq Capital Market under the symbol “HGEN.” The aggregate gross proceeds from the sale of the full 9,200,000 shares in the offering were approximately $78.2 million. The Company expects to use the proceeds from the offering to support its manufacturing, production and commercial preparation activities relating to lenzilumab as a potential therapy for COVID-19 patients and for working capital and other general corporate purposes. 2021 Underwritten Public Offering On March 30, 2021, we entered into an underwriting agreement (the “Underwriting Agreement”) with Jefferies LLC, Credit Suisse Securities (USA) LLC and Cantor, as representatives of the several underwriters, in connection with the public offering of 5,000,000 shares of our common stock. In addition, we granted the underwriters a 30-day option to purchase an additional 750,000 shares of our common stock. The initial offering closed on April 5, 2021. On May 3, 2021, we closed on the sale of an additional 427,017 shares of our common stock related to the exercise of the underwriters’ 30-day option. The aggregate gross proceeds from the sale of the 5,427,017 shares in the offering, inclusive of the additional shares purchased by the underwriters, were approximately $100.4 million. The net proceeds from this offering, after deducting underwriting discounts and offering costs, were approximately $94.2 million. F-22 Table of Contents The Company has reserved the following shares of common stock for issuance as of December 31, 2021: Warrants to purchase common stock 31,238 Options: Outstanding under the 2020 Equity Incentive Plan 1,962,489 Outstanding under the 2012 Equity Incentive Plan 2,467,417 Available for future grants under the 2020 Equity Incentive Plan 5,004,035 9,465,179 Controlled Equity Offering On December 31, 2020, the Company entered into the Sales Agreement with Cantor, under which the Company could issue and sell from time-to-time shares of the Company’s common stock, having an aggregate gross sales price of up to $100.0 million through Cantor, as sales agent. During the year ended December 31, 2021, the Company issued and sold 6,408,087 shares of common stock pursuant to the Sales Agreement, and received net proceeds of approximately $65.7 million, after deducting fees and expenses. As of December 31, 2021, the Company had the ability to offer and sell shares of common stock having an aggregate offering price of up to $32.3 million under the prospectus supplement dated August 13, 2021 to the Company’s prospectus dated September 14, 2020 filed in respect of the Sales Agreement. See Note 13 below for additional information related to the Sales Agreement. 2020 Equity Plan On July 27, 2020, the Board unanimously approved, and recommended that the Company’s stockholders approve, the 2020 Equity Plan, to ensure that the Board and its compensation committee (the “Compensation Committee”) will be able to make the types of awards, and covering the number of shares, as necessary to meet the Company’s compensatory needs. On July 29, 2020, the 2020 Equity Plan was approved by the holders of approximately 63% of the Company’s outstanding shares of common stock on that date. The 2020 Equity Plan became effective on September 11, 2020 following the Effective Time of the reverse stock split. Immediately following the Effective Time, a total of 7,000,000 shares of the Company’s common stock were reserved for issuance under the 2020 Equity Plan. The Board or Compensation Committee may grant the following types of awards under the 2020 Equity Plan: stock options, stock appreciation rights, restricted stock, stock awards, restricted stock units, performance shares, performance units, cash-based awards and substitute awards. The 2020 Equity Plan will remain in effect until the tenth anniversary of its effective date, unless terminated earlier by the Board. For options, the per share exercise price may not be less than the fair market value of a Company common share on the date of grant. Options generally vest and become exercisable over three years and expire 10 years from the date of grant. As of December 31, 2021, there were 5,004,035 shares available for grant under the 2020 Equity Incentive Plan. 2012 Equity Plan The 2020 Equity Plan replaced the 2012 Equity Plan, under which no further grants will be made. However, any outstanding awards under the 2012 Equity Plan will continue in accordance with the terms of the 2012 Equity Plan and any award agreement executed in connection with such outstanding awards. At the Effective Time of the reverse stock split, proportionate adjustments were made to the number of shares covered by, and the exercise price applicable to, each outstanding stock option award under the 2012 Equity Plan to give effect to the Split Ratio and the reverse stock split. Under the 2012 Equity Plan, the Company could grant shares, stock units, stock appreciation rights, performance cash awards and/or options to employees, directors, consultants, and other service providers. As of December 31, 2021, there were no shares available for grant under the 2012 Equity Incentive Plan. F-23 Table of Contents Stock Option Activity The following table summarizes stock option activity for the years ended December 31, 2021 and 2020: Number of Shares Weighted Average Exercise Price (per share)(1) Weighted- Average Remaining Contractual Term (in years) Aggregate Intrinsic Value ($000's)(2) Outstanding at January 1, 2020 3,176,336 $ 4.75 Granted 985,164 7.35 Exercised (429,330 ) 3.55 Cancelled (expired) (21 ) 58.40 Outstanding at December 31, 2020 3,732,149 $ 5.57 Granted 1,444,176 12.58 Exercised (582,936 ) 3.98 Cancelled (forfeited) (81,711 ) 7.09 Cancelled (expired) (81,772 ) 13.71 Outstanding at December 31, 2021 4,429,906 $ 7.89 7.4 $ 1,087 Options vested and expected to vest 4,281,658 $ 7.77 7.3 $ 1,084 Exercisable 2,951,257 $ 6.08 6.7 $ 1,017 ______________________ (1) The weighted average price per share is determined using exercise price per share for stock options. (2) The aggregate intrinsic value is calculated as the difference between the exercise price of the option and the fair value of the Company’s common stock for in-the-money options at December 31, 2021. The stock options outstanding and exercisable by exercise price at December 31, 2021 are as follows: Stock Options Outstanding Stock Options Exercisable Weighted- Average Remaining Weighted- Average Weighted- Average Contractual Exercise Exercise Number Life Price Number of Price Range of Exercise Prices of Shares In Years Per Share Shares Per Share $1.90 - $2.25 216,795 8.00 $ 2.16 169,069 $ 2.14 $3.33 1,894,168 6.18 $ 3.33 1,894,168 $ 3.33 $3.50 - $9.65 987,674 9.04 $ 6.92 328,349 $ 7.33 $10.64 - $15.90 274,425 9.17 $ 14.22 113,174 $ 12.86 $16.07 733,240 8.21 $ 16.07 183,310 $ 16.07 $16.90 - $20.00 293,604 5.40 $ 17.19 258,187 $ 16.96 $20.68 30,000 9.43 $ 20.68 5,000 $ 20.68 4,429,906 7.40 $ 7.89 2,951,257 $ 6.08 The total fair value of options vested for the years ended December 31, 2021 and 2020 was $2.3 million and $2.2 million, respectively. F-24 Table of Contents Stock-Based Compensation The Company’s stock-based compensation expense for stock options is estimated at the grant date based on the award’s fair value as calculated by the Black-Scholes option pricing model and is recognized as expense over the requisite service period. The Black-Scholes option pricing model requires various highly judgmental assumptions including expected volatility and expected term. The expected volatility is based on the combined historical stock volatilities of the Company’s own common stock and that of its publicly listed peers over a period equal to the expected terms of the options as the Company does not have a sufficient trading history to rely solely on the volatility of its own common stock. To estimate the expected term, the Company has opted to use the simplified method, which is the use of the midpoint of the vesting term and the contractual term. If any of the assumptions used in the Black-Scholes option pricing model changes significantly, stock-based compensation expense may differ materially in the future from that recorded in the current period. In addition, the Company is required to estimate the expected forfeiture rate and only recognize expense for those shares expected to vest. The Company estimates the forfeiture rate based on historical experience and its expectations regarding future pre-vesting termination behavior of employees. The Company reviews its estimate of the expected forfeiture rate annually, and stock-based compensation expense is adjusted accordingly. The weighted-average fair value-based measurement of stock options granted under the Company’s stock plans in the years ended December 31, 2021 and 2020 was $10.32 and $7.35 per share, respectively. The fair value-based measurement of stock options granted under the Company’s stock plans was estimated at the date of grant using the Black-Scholes model with the following assumptions: Year Ended December 31, 2021 2020 Expected term 5 - 6 years 5 - 6 years Expected volatility 104% - 109% 95% - 111% Risk-free interest rate 0.98% - 1.35% 0.28% - 1.57% Expected dividend yield 0% 0% Total expense for stock option grants recognized was as follows: Year Ended December 31, 2021 2020 General and administrative $ 4,028 $ 1,773 Research and development 1,340 337 Total stock-based compensation $ 5,368 $ 2,110 At December 31, 2021, the Company had $12.2 million of total unrecognized compensation expense, net of estimated forfeitures, related to outstanding stock options that will be recognized over a weighted-average period of 2.3 years.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2021
Income Tax Disclosure [Abstract]
Income Taxes	9. Income Taxes No provision for federal income taxes has been recorded for the years ended December 31, 2021 and 2020 due to net losses and the valuation allowance established. Deferred tax assets and liabilities reflect the net tax effects of net operating loss and tax credit carryovers and the temporary differences between the carrying amounts of assets and liabilities for financial reporting and the amounts used for income tax purposes. Significant components of the Company's deferred tax assets are as follows: As of December 31, 2021 2020 Deferred tax assets: Net operating losses $ 143,732 $ 75,149 Research and other credits 2,178 2,178 Stock based compensation 3,354 3,256 In-Process research and development 1,132 1,193 Other 230 665 Total deferred tax assets 150,626 82,441 Valuation allowance (150,626 ) (82,441 ) Net deferred tax assets $ - $ - F-25 Table of Contents A reconciliation of the statutory tax rates and the effective tax rates for the years ended December 2021 and 2020 is as follows: Year Ended December 31, 2021 2020 Statutory rate 21.0 % 21.0 % Valuation allowance (28.5 )% (27.9 )% Nondeductible stock compensation 0.4 % - % Other 7.1 % 6.9 % Effective tax rate - % - % On December 22, 2017, the President of the United States signed into law the Tax Cuts and Jobs Act tax reform legislation. This legislation makes significant change in U.S. tax law including a reduction in the corporate tax rates, changes to net operating loss carryforwards and carrybacks, and a repeal of the corporate alternative minimum tax. The legislation reduced the U.S. corporate tax rate from 35% to 21%. As a result of the enacted law, the Company was required to revalue deferred tax assets and liabilities at the 21% for the year ended December 31, 2017. This revaluation resulted in additional income tax expense of $21.6 million in continuing operations, a corresponding reduction in the net deferred tax asset, an additional income tax benefit of $21.6 million, and a corresponding reduction in the valuation allowance on net deferred tax assets. The other provisions of the Tax Cuts and Jobs Act did not have a material impact on the 2017, 2018 or 2019 consolidated financial statements. Realization of deferred tax assets is dependent upon future earnings, if any, the timing and amount of which are uncertain. Accordingly, the net deferred tax assets have been fully offset by a valuation allowance. The valuation allowance increased by $68.2 million during 2021 and increased by $25.0 million during 2020. At December 31, 2021, the Company had federal net operating loss carryforwards of approximately $166.2 million, which expire in the years 2022 2037 2028 2041 At December 31, 2021, the Company had federal research and development credit carryforwards of approximately $1.3 million, which expire in the years 2022 2035 During 2013, the Company completed a Section 382 study in accordance with the Internal Revenue Code of 1986, as amended, and similar state provisions. The study concluded that the Company has experienced several ownership changes since inception. This causes the Company's utilization of its net operating loss and tax credit carryforwards to be subject to substantial annual limitations. These results are reflected in the above carryforward amounts and deferred tax assets. The Company's ability to utilize its net operating loss and tax credit carryforwards are further limited as a result of subsequent ownership changes. All such limitations could result in the expiration of carryforwards before they are utilized. An ownership change may have occurred during 2015 or 2016 or 2017 or 2018, or all four years and in connection with the Restructuring Transactions that occurred in 2018. As a result, tax attributes such as net operating losses and research and development credits may be subject to further limitation. FASB ASC 740 requires that the Company recognize the financial statement effects of a tax position when it is more likely than not, based on the technical merits, that the position will be sustained upon examination. A reconciliation of the beginning and ending amount of unrecognized tax benefits is as follows: Balance at December 31, 2019 1,060 Additions based on tax positions related to prior year - Additions based on tax positions related to current year - Balance at December 31, 2020 1,060 Additions based on tax positions related to prior year - Additions based on tax positions related to current year - Balance at December 31, 2021 $ 1,060 There were no interest or penalties related to unrecognized tax benefits. Substantially all of the unrecognized tax benefit, if recognized to offset future taxable income would affect the Company’s tax rate. The Company does not anticipate that the amount of existing unrecognized tax benefits will significantly increase or decrease within the next 12 months. Because of net operating loss carryforwards, substantially all of the Company’s tax years remain open to federal tax and state tax examination. F-26 Table of Contents The Company files income tax returns in the U.S. federal jurisdiction, California and Florida. Federal and California corporation income tax returns beginning with the 2001 tax year remain subject to examination by the Internal Revenue Service and the California Franchise Tax Board and the Florida corporate income tax returns beginning with 2018 remain subject to examination by the Florida Department of Revenue, respectively.

Employee Benefit Plan

Employee Benefit Plan	12 Months Ended
	Dec. 31, 2021
Retirement Benefits [Abstract]
Employee Benefit Plan	10. Employee Benefit Plan The Company has established a 401(k) tax-deferred savings plan (the “401(k) Plan”), which permits participants to make contributions by salary deduction pursuant to Section 401(k) of the Internal Revenue Code. The Company is responsible for administrative costs of the 401(k) Plan. The Company may, at its discretion, make matching contributions to the 401(k) Plan. The Company contributed $23,000 in matching contributions to the 401(k) Plan for the year ended December 31, 2021. No employer contribution was made to the plan for the year ended December 31, 2020.

Litigation

Litigation	12 Months Ended
	Dec. 31, 2021
Litigation [Abstract]
Litigation	11. Litigation Avid Arbitration On December 17, 2021, Avid Bioservices, Inc. (“Avid”) filed a Demand for Arbitration claiming more than $20.5 million in damages against the Company with the American Arbitration Association entitled, Avid Bioservices, Inc. v. Humanigen, Inc. On January 6, 2022, the Company filed an Answer to Avid’s Demand, denying the allegations and asserting affirmative defenses. An Arbitration Hearing date has not yet been scheduled. The Company will vigorously defend itself, assert all available claims against Avid, and seek all available remedies. Savant Litigation The Company is currently involved in litigation with Savant in an action captioned Humanigen, Inc. v. Savant Neglected Diseases, LLC, C.A. No. N17C-07-068-PRW [CCLD]. In this litigation, the Company filed a complaint against Savant in the Superior Court of the State of Delaware, New Castle County (the “Superior Court”). The Company asserted breach of contract, declaratory judgment and fraudulent inducement claims against Savant arising under the MDC Agreement. Subsequently, Savant filed a complaint against the Company and Madison Joint Venture LLC (“Madison”) in the Delaware Court of Chancery (the “Chancery Action”) seeking to “recover as damages amounts owed to it under the MDC Agreement, and to reclaim Savant’s intellectual property,” among other things. This action was subsequently consolidated with the Superior Court action. On July 9, 2021, the Court issued a memorandum opinion resolving various summary judgment motions. In the opinion, the Court granted the Company’s motion for summary judgment on certain of Savant’s claims. Accordingly, Savant’s claims are now limited to breach of contract and fraudulent transfer claims. Savant’s summary judgment motion was denied in its entirety leaving Humanigen’s fraud and contract claims against Savant for trial. On November 22, 2021, the Court held a scheduling conference regarding the trial date. Subsequently, on December 15, 2021, the Court scheduled a five-day jury for the week of September 12, 2022, with a pre-trial conference scheduled for August 12, 2022. The Company is prepared to defend itself vigorously and pursue all remedies available against Savant for breach of contract and fraud. Private Placement Litigation On June 15, 2020, a complaint was filed against the Company and Dr. Durrant in the Commercial Division of the Supreme Court of the State of New York. The case caption is Alliance Texas Holdings, LLC et al. v. Humanigen, Inc. et al. F-27 Table of Contents On April 19, 2021, the Company and Noble entered into a confidential settlement agreement in respect of a separate lawsuit brought by Noble related to the Private Placement (the “Noble Case”) captioned Noble Capital Markets, Inc. v. Humanigen, Inc., Case No. 9:20-CV-81131-WPD, pursuant to which the Noble Case was dismissed with prejudice. On February 24, 2022, the Company entered into a confidential settlement agreement and release with respect to the claims raised in the Alliance Texas Holding Case, pursuant to which the Alliance Texas Holding Case has been discontinued with prejudice, except as to two Plaintiffs whose claims comprised less than 10% of the total alleged investments, as to whom the case will be discontinued without prejudice.

License and Collaboration Agree

License and Collaboration Agreements	12 Months Ended
	Dec. 31, 2021
License And Collaboration Agreements
License and Collaboration Agreements	12. License and Collaboration Agreements Kite Agreement On May 30, 2019, the Company entered into a collaboration agreement (the “Kite Agreement”) with Kite Pharmaceuticals, Inc. (“Kite”), pursuant to which the Company and Kite are conducting a multi-center Phase 1b/2 study of lenzilumab with Kite’s Yescarta in patients with relapsed or refractory B-cell lymphoma, including diffuse large B-cell lymphoma (“DLBCL”). On April 19, 2021, the Company announced positive preliminary data from this study. As a result of this positive preliminary data and the conclusion of the Phase 1b portion of the study, the Company elected to terminate the clinical collaboration agreement with Kite. Enrollment in the Phase 1b portion of the study is closed and the study itself shall be closed by the fourth quarter of 2021. The effective date of termination of the clinical collaboration with Kite was December 31, 2021. Until the Phase 1b portion of the study is terminated and the last subject transitioned onto the Kite long term follow up protocol, Humanigen and Kite will cooperate to ensure the orderly wind down of study activities. The Company is preparing to initiate a Company-sponsored Phase 3 study with commercially available CD19 CAR-T therapies in non-Hodgkin lymphoma in 2022 and met with FDA in December 2021 to discuss the study protocol. The Company currently plans to enroll more than 150 patients in the study. During the years ended December 31, 2021 and 2020, the Company paid $0 and $2.0 million, respectively, to Kite towards its contribution for the study, which payments were recorded as Research and development expense. Mayo Agreement On June 19, 2019, the Company entered into an exclusive worldwide license agreement (the “Mayo Agreement”) with the Mayo Foundation for Medical Education and Research (“Mayo”) for certain technologies used to create CAR-T cells lacking GM-CSF expression through various gene-editing tools including CRISPR-Cas9 (“GM-CSF KO Pursuant to the Mayo Agreement, the Company paid $0.2 million to Mayo in June 2020, which payment was accrued as Research and development expense in June 2019. The Mayo Agreement also requires the payment of milestones and royalties upon the achievement of certain regulatory and commercialization milestones. Zurich Agreement On July 19, 2019, the Company entered into an exclusive worldwide license agreement (the “Zurich Agreement”) with the University of Zurich (“UZH”) for technology used to prevent or treat GvHD through GM-CSF neutralization. The Zurich Agreement covers various patent applications filed by UZH which complement and broaden the Company’s position in the application of GM-CSF and expands the Company’s development platform to include improving allogeneic Hematopoietic Stem Cell Transplantation (“HSCT”). The Zurich Agreement requires the payment of nominal annual maintenance fees and milestones and royalties upon the achievement of certain regulatory and commercialization milestones. Clinical Trial Agreement with the National Institute of Allergy and Infectious Diseases On July 24, 2020, the Company entered into a clinical trial agreement (the “ACTIV-5 Clinical Trial Agreement”) with the National Institute of Allergy and Infectious Diseases (“NIAID”), part of NIH, which is part of the U.S. Government Department of Health and Human Services, as represented by the Division of Microbiology and Infectious Diseases. Pursuant to the ACTIV-5 Clinical Trial Agreement, lenzilumab is being evaluated in the NIAID-sponsored ACTIV-5/BET-B in hospitalized patients with COVID-19. The ACTIV-5/BET-B study protocol was modified to include baseline CRP below 150 mg/L (the CRP subgroup) as the primary analysis population. The ACTIV-5/BET-B study has reached its target enrollment with over 400 patients enrolled that met this criterion and the Company anticipates top-line data in late first quarter or early second quarter of 2022. See Note 1 above for further information regarding ACTIV-5/BET-B. F-28 Table of Contents Pursuant to the ACTIV-5 Clinical Trial Agreement, NIAID will serve as sponsor and is responsible for funding, supervising and overseeing ACTIV-5/BET-B. The Company will be responsible for providing lenzilumab to NIAID without charge and in quantities to ensure a sufficient supply of lenzilumab. The ACTIV-5 Clinical Trial Agreement imposes additional obligations on the Company that are reasonable and customary for clinical trial agreements of this nature, including in respect of compliance with data privacy laws and potential indemnification obligations. The Company will have access to data from ACTIV-5/BET-B once concluded. CRADA On November 5, 2020, the Company and the Department of Defense (“DoD”) Joint Program Executive Office for Chemical, Biological, Radiological and Nuclear Defense (“JPEO-CBRND” or “JPEO”) entered into a Cooperative Research and Development Agreement (“CRADA”) in collaboration with the Biomedical Advanced Research and Development Authority (“BARDA”), part of the Office of the Assistant Secretary for Preparedness and Response (“ASPR”) at the U.S. Department of Health and Human Services (“HHS”), in support of Operation Warp Speed (“OWS”), to assist in the development of lenzilumab, in connection with a potential EUA for COVID-19. Pursuant to the CRADA, the Company has been provided access to a full-scale, integrated team of OWS manufacturing, and regulatory subject matter experts, leading decision makers and statistical support in its efforts to apply for EUA for lenzilumab as a potential treatment for COVID-19.

Subsequent Events

Subsequent Events	12 Months Ended
	Dec. 31, 2021
Subsequent Events [Abstract]
Subsequent Events	13. Subsequent Events Subsequent to December 31, 2021 and through the date of this filing, the Company issued and sold 1,301,548 shares of common stock under the Sales Agreement for net proceeds of $3.7 million. On February 24, 2022, the Company entered into a confidential settlement agreement and release with respect to the claims raised in the Alliance Texas Holding Case. See Note 11 above for further information.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2021
Accounting Policies [Abstract]
Basis of Presentation and Use of Estimates	Basis of Presentation and Use of Estimates The accompanying Consolidated Financial Statements have been prepared in accordance with U.S. generally accepted accounting principles (“GAAP”) and include all adjustments necessary for the presentation of the Company’s consolidated financial position, results of operations and cash flows for the periods presented. The Consolidated Financial Statements include the accounts of the Company and its wholly owned subsidiaries. These financial statements have been prepared on a basis that assumes that the Company will continue as a going concern, which contemplates the realization of assets and the satisfaction of liabilities and commitments in the normal course of business. The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts and disclosures reported in the Consolidated Financial Statements and accompanying notes. Actual results could differ materially from those estimates. The Company believes judgment is involved in accounting for the determination of revenue recognition, the fair value-based measurement of stock-based compensation and accruals. The Company evaluates its estimates and assumptions as facts and circumstances dictate. As future events and their effects cannot be determined with precision, actual results could differ from these estimates and assumptions, and those differences could be material to the Consolidated Financial Statements.
Concentration of Credit Risk	Concentration of Credit Risk Cash, cash equivalents, and marketable securities consist of financial instruments that potentially subject the Company to a concentration of credit risk in the event of a default by the related financial institution holding the securities, to the extent of the value recorded in the consolidated balance sheet. The Company invests cash that is not required for immediate operating needs primarily in highly liquid instruments with lower credit risk. The Company has established guidelines relating to the quality, diversification, and maturities of securities to enable the Company to manage its credit risk.
Cash and Cash Equivalents	Cash and Cash Equivalents The Company considers all highly liquid investments with an original maturity of 90 days or less at the time of purchase to be cash equivalents. Cash and cash equivalents consist of deposits with commercial banks in checking, interest-bearing and demand money market accounts.
Debt Issuance Costs	Debt Issuance Costs Debt issuance costs related to a recognized debt liability are presented on the consolidated balance sheets as a direct deduction from the carrying amount of that debt liability, consistent with debt discounts and are amortized to interest expense over the term of the related debt using the effective interest method.
Research and Development Expenses	Research and Development Expenses Development costs incurred in the research and development of new product candidates are expensed as incurred, including expenses that may or may not be reimbursed under research and development collaboration arrangements. Research and development costs include, but are not limited to, salaries, benefits, stock-based compensation, laboratory supplies, allocated overhead, fees for professional service providers and costs associated with product development efforts, including the cost of consultants and contract manufacturing organizations (“CMOs”) that manufacture drug products for use in our preclinical studies and clinical trials as well as all other expenses associated with preclinical studies and clinical trials. The Company estimates preclinical study and clinical trial expenses based on the services performed, pursuant to contracts with research institutions and clinical research organizations that conduct and manage preclinical studies and clinical trials on its behalf. In accruing service fees, the Company estimates the time period over which services will be performed and the level of effort to be expended in each period. If the actual timing of the performance of services or the level of effort varies from the estimate, the Company will adjust the accrual accordingly. Payments made to third parties under these arrangements in advance of the receipt of the related services are recorded as prepaid expenses until the services are rendered. The Company records upfront and milestone payments made to third parties under licensing arrangements as an expense. Upfront payments are recorded when incurred and milestone payments are recorded when the specific milestone has been achieved.
Revenue Recognition	Revenue Recognition The Company’s revenue to date has been generated primarily through license agreements and research and development collaboration agreements. The Company recorded $3.6 million and $0.3 million for the years ending December 31, 2021 and 2020, respectively, related to the November 3, 2020 License Agreement (the “South Korea Agreement”) with KPM Tech Co., Ltd. (“KPM”) and its affiliate, Telcon RF Pharmaceutical, Inc. (“Telcon”), as further described in Note 3. Commencing January 1, 2018, the Company recognizes revenue in accordance with Financial Accounting Standards Board (“FASB”) Accounting Standards Codification (“ASC”) Topic 606 – Revenue from Contracts with Customers Revenue under technology licenses and collaborative agreements typically consists of nonrefundable and/or guaranteed license fees, collaborative research funding, and various milestone and future product royalty or profit-sharing payments. The fair value of deliverables under the arrangement may be derived using a best estimate of selling price if vendor specific objective evidence and third-party evidence is not available. Deliverables under the arrangement will be separate units of accounting if a delivered item has value to the customer on a standalone basis and if the arrangement includes a general right of return for the delivered item, delivery or performance of the undelivered item is considered probable and substantially in the Company’s control. F-11 Table of Contents The Company recognizes upfront license payments as revenue upon delivery of the license only if the license has standalone value from any undelivered performance obligations and that value can be determined. The undelivered performance obligations typically include manufacturing or development services or research and/or steering committee services. If the fair value of the undelivered performance obligations can be determined, then these obligations would be accounted for separately. If the license is not considered to have standalone value, then the license and other undelivered performance obligations would be accounted for as a single unit of accounting. In this case, the license payments and payments for performance obligations are recognized as revenue over the estimated period of when the performance obligations are performed or deferred indefinitely until the undelivered performance obligation is determined. Whenever the Company determines that an arrangement should be accounted for as a single unit of accounting, the Company determines the period over which the performance obligations will be performed, and revenue will be recognized. Revenue is recognized using a proportional performance or straight-line method. The proportional performance method is used when the level of effort required to complete performance obligations under an arrangement can be reasonably estimated. The amount of revenue recognized under the proportional performance method is determined by multiplying the total payments under the contract, excluding royalties and payments contingent upon achievement of milestones, by the ratio of the level of effort performed to date to the estimated total level of effort required to complete performance obligations under the arrangement. If the Company cannot reasonably estimate the level of effort to complete performance obligations under an arrangement, the Company recognizes revenue under the arrangement on a straight-line basis over the period the Company is expected to complete its performance obligations. Significant management judgment is required in determining the level of effort required under an arrangement and the period over which the Company is expected to complete its performance obligations under an arrangement. The Company’s collaboration agreements typically entitle the Company to additional payments upon the achievement of development, regulatory and sales performance-based milestones. If the achievement of a milestone is considered probable at the inception of the collaboration, the related milestone payment is included with other collaboration consideration, such as upfront fees and research funding, in the Company’s revenue calculation. Typically, these milestones are not considered probable at the inception of the collaboration. As such, milestones will typically be recognized in one of two ways depending on the timing of when the milestone is achieved. If the milestone is achieved during the performance period, then the Company will only recognize revenue to the extent of the proportional performance achieved at that date, or the proportion of the straight-line basis achieved at that date, and the remainder will be recorded as deferred revenue to be amortized over the remaining performance period. If the milestone is achieved after the performance period has completed and all performance obligations have been delivered, then the Company will recognize the milestone payment as revenue in its entirety in the period the milestone was achieved. See Note 3 for information on the South Korea Agreement.
Leases	Leases The Company accounts for a contract as a lease when it has the right to control the asset for a period of time while obtaining substantially all of the asset's economic benefits. The Company determines if an arrangement is a lease or contains an embedded lease at inception. For arrangements that meet the definition of a lease, the Company determines the initial classification and measurement of its operating right-of-use asset and operating lease liability at the lease commencement date and thereafter if modified. The lease term includes any renewal options that the Company is reasonably assured to exercise. The present value of lease payments is determined by using the interest rate implicit in the lease, if that rate is readily determinable; otherwise, the Company uses its estimated secured incremental borrowing rate for that lease term. In addition to rent, the leases may require the Company to pay additional amounts for taxes, insurance, maintenance, and other expenses, which are generally referred to as non-lease components. The Company has elected to not separate lease and non-lease components. Rent expense is recognized on a straight-line basis over the reasonably assured lease term based on the total lease payments and is included in operating expenses in the consolidated statements of operations. The Company has made an accounting policy election to not recognize short-term leases, or leases that have a lease term of 12 months or less at commencement date, within its consolidated balance sheets and to recognize those lease payments in the consolidated statements of operations on a straight-line basis over the lease term.
Stock-Based Compensation Expense	Stock-Based Compensation Expense The Company measures stock-based compensation expense for stock awards at the grant date, based on the fair value-based measurement of the award, and the expense is recorded over the related service period, generally the vesting period, net of estimated forfeitures. The Company calculates the fair value-based measurement of stock options using the Black-Scholes valuation model and the simplified method and recognizes expense using the straight-line attribution approach.
Income Taxes	Income Taxes The Company accounts for income taxes under an asset-and-liability approach. Deferred income taxes reflect the impact of temporary differences between assets and liabilities recognized for tax and financial reporting purposes measured by applying enacted tax rates and laws that will be in effect when the differences are expected to reverse, net operating loss carryforwards and tax credits. Valuation allowances are provided when necessary to reduce net deferred tax assets to an amount that is more likely than not to be realized. The Company’s policy is to include interest and penalties related to unrecognized tax benefits within the Company’s provision for income taxes.
Net Loss Per Common Share	Net Loss Per Common Share Basic net loss per common share is calculated by dividing the net loss attributable to common stockholders by the weighted-average number of common shares outstanding during the period, without consideration for potentially dilutive securities. Diluted net loss per share is computed by dividing the net loss attributable to common stockholders by the weighted-average number of common shares and potentially dilutive securities outstanding for the period determined using the treasury-stock and if-converted methods. For purposes of the diluted net loss per share calculation, stock options, common stock warrants and convertible debt are considered to be potentially dilutive securities but are excluded from the calculation of diluted net loss per share because their effect would be anti-dilutive and therefore, basic and diluted net loss per share were the same for all periods presented. The Company’s potential dilutive securities, which include stock options, warrants and convertible debt have been excluded from the computation of diluted net loss per share as the effect would be to reduce the net loss per common share and be antidilutive. Therefore, the denominator used to calculate both basic and diluted net loss per common share is the same in all periods presented. The following shares subject to outstanding potentially dilutive securities have been excluded from the computations of diluted net loss per common share as the effect of including such securities would be antidilutive: As of December 31, 2021 2020 Options to purchase common stock 4,429,906 3,728,149 Warrants to purchase common stock 31,238 51,238 Convertible debt 510,986 - 4,972,130 3,779,387
Segment Reporting	Segment Reporting The Company determines its segment reporting based upon the way the business is organized for making operating decisions and assessing performance. The Company operates in only one segment, which is related to the development of pharmaceutical products.
Recent Accounting Pronouncements	Recent Accounting Pronouncements In December 2019, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2019-12, Simplifying the Accounting for Income Taxes. ASU No. 2019-12 eliminates certain exceptions related to the approach for intra-period tax allocation, the methodology for calculating income taxes in an interim period and the recognition of deferred tax liabilities for outside basis differences. It also clarifies and simplifies other aspects of the accounting for income taxes. ASU 2019-12 is effective for fiscal years beginning after December 15, 2020, and interim periods within those fiscal years. The Company adopted ASU No. 2019-12 on January 1, 2021, which did not have any impact to the Company’s Consolidated Financial Statements. In August 2020, the FASB issued ASU No. 2020-06, “Accounting for Convertible Instruments and Contracts in an Entity’s Own Equity”, as part of its overall simplification initiative to reduce costs and complexity of applying accounting standards while maintaining or improving the usefulness of the information provided to users of financial statements. Among other changes, the new guidance removes from U.S. GAAP, separation models for convertible debt that require the convertible debt to be separated into a debt and equity component, unless the conversion feature is required to be bifurcated and accounted for as a derivative or the debt is issued at a substantial premium. As a result, after adopting the guidance, entities will no longer separately present such embedded conversion features in equity and will instead account for the convertible debt wholly as debt. The new guidance also requires use of the “if-converted” method when calculating the dilutive impact of convertible debt on earnings per share, which is consistent with the Company’s current accounting treatment under the current guidance. The guidance is effective for the Company’s financial statements issued for fiscal years beginning after December 15, 2023, and interim periods within those fiscal years, with early adoption permitted, but only at the beginning of the fiscal year. The Company early adopted the new guidance on January 1, 2021, using the modified retrospective approach. The adoption did not have any impact to the Company’s Consolidated Financial Statements.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2021
Accounting Policies [Abstract]
Schedule of antidilutive securities excluded from computations of diluted net loss per common share	The following shares subject to outstanding potentially dilutive securities have been excluded from the computations of diluted net loss per common share as the effect of including such securities would be antidilutive: As of December 31, 2021 2020 Options to purchase common stock 4,429,906 3,728,149 Warrants to purchase common stock 31,238 51,238 Convertible debt 510,986 - 4,972,130 3,779,387

License Revenue (Tables)

License Revenue (Tables)	12 Months Ended
	Dec. 31, 2021
License Revenue
Schedule of contract liability	The following table presents changes in the Company’s contract liability for the years ended December 31, 2021 and 2020 (in thousands): Balance at January 1, 2020 $ - Additions (1) 4,528 Deductions for performance obligations satisfied: In current period (312 ) Balance at December 31, 2020 4,216 Additions (2) 4,542 Deductions for performance obligations satisfied: In current period (1,721 ) In prior period (1,874 ) Balance at December 31, 2021 $ 5,163 _______________ ​ (1) ​ (2)

Accrued Expenses (Tables)

Accrued Expenses (Tables)	12 Months Ended
	Dec. 31, 2021
Accrued Liabilities, Current [Abstract]
Schedule of accrued expenses	Accrued expenses consist of the following (in thousands): As of December 31, 2021 2020 Accrued contract manufacturing-related $ 16,174 $ - Accrued milestone and royalties 2,736 2,368 Accrued clinical trial-related 160 - Accrued compensation-related 44 530 Accrued other 768 277 $ 19,882 $ 3,175

Debt (Tables)

Debt (Tables)	12 Months Ended
	Dec. 31, 2021
Disclosure Text Block [Abstract]
Schedule of Outstanding Future Payments Associated Company's Term Loan	The following table summarizes the outstanding future payments of principal and interest associated with the Company’s Term Loan as of December 31, 2021 (in thousands): 2022 $ 2,218 2023 10,800 2024 13,671 2025 5,153 Total payments 31,842 Less amount representing interest (5,155 ) Notes payable, gross 26,687 Less: Unamortized portion of EOT charge (1,264 ) Less: Unamortized discount on notes payable (159 ) Less: Unamortized debt issuance costs (258 ) Long-term debt 25,006 Less current portion - Long-term debt, net of current portion $ 25,006

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	12 Months Ended
	Dec. 31, 2021
Stockholders' Equity Note [Abstract]
Schedule of shares of common stock reserved for issuance	The Company has reserved the following shares of common stock for issuance as of December 31, 2021: Warrants to purchase common stock 31,238 Options: Outstanding under the 2020 Equity Incentive Plan 1,962,489 Outstanding under the 2012 Equity Incentive Plan 2,467,417 Available for future grants under the 2020 Equity Incentive Plan 5,004,035 9,465,179
Summary of stock option activity	The following table summarizes stock option activity for the years ended December 31, 2021 and 2020: Number of Shares Weighted Average Exercise Price (per share)(1) Weighted- Average Remaining Contractual Term (in years) Aggregate Intrinsic Value ($000's)(2) Outstanding at January 1, 2020 3,176,336 $ 4.75 Granted 985,164 7.35 Exercised (429,330 ) 3.55 Cancelled (expired) (21 ) 58.40 Outstanding at December 31, 2020 3,732,149 $ 5.57 Granted 1,444,176 12.58 Exercised (582,936 ) 3.98 Cancelled (forfeited) (81,711 ) 7.09 Cancelled (expired) (81,772 ) 13.71 Outstanding at December 31, 2021 4,429,906 $ 7.89 7.4 $ 1,087 Options vested and expected to vest 4,281,658 $ 7.77 7.3 $ 1,084 Exercisable 2,951,257 $ 6.08 6.7 $ 1,017 ______________________ (1) The weighted average price per share is determined using exercise price per share for stock options. (2) The aggregate intrinsic value is calculated as the difference between the exercise price of the option and the fair value of the Company’s common stock for in-the-money options at December 31, 2021.
Schedule of stock options outstanding and exercisable by exercise price	The stock options outstanding and exercisable by exercise price at December 31, 2021 are as follows: Stock Options Outstanding Stock Options Exercisable Weighted- Average Remaining Weighted- Average Weighted- Average Contractual Exercise Exercise Number Life Price Number of Price Range of Exercise Prices of Shares In Years Per Share Shares Per Share $1.90 - $2.25 216,795 8.00 $ 2.16 169,069 $ 2.14 $3.33 1,894,168 6.18 $ 3.33 1,894,168 $ 3.33 $3.50 - $9.65 987,674 9.04 $ 6.92 328,349 $ 7.33 $10.64 - $15.90 274,425 9.17 $ 14.22 113,174 $ 12.86 $16.07 733,240 8.21 $ 16.07 183,310 $ 16.07 $16.90 - $20.00 293,604 5.40 $ 17.19 258,187 $ 16.96 $20.68 30,000 9.43 $ 20.68 5,000 $ 20.68 4,429,906 7.40 $ 7.89 2,951,257 $ 6.08
Schedule of fair value-based measurement of stock options granted under the entity's stock plans estimated using Black-Scholes model	The weighted-average fair value-based measurement of stock options granted under the Company’s stock plans in the years ended December 31, 2021 and 2020 was $10.32 and $7.35 per share, respectively. The fair value-based measurement of stock options granted under the Company’s stock plans was estimated at the date of grant using the Black-Scholes model with the following assumptions: Year Ended December 31, 2021 2020 Expected term 5 - 6 years 5 - 6 years Expected volatility 104% - 109% 95% - 111% Risk-free interest rate 0.98% - 1.35% 0.28% - 1.57% Expected dividend yield 0% 0%
Schedule of total stock-based compensation expense recognized	Total expense for stock option grants recognized was as follows: Year Ended December 31, 2021 2020 General and administrative $ 4,028 $ 1,773 Research and development 1,340 337 Total stock-based compensation $ 5,368 $ 2,110

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2021
Income Tax Disclosure [Abstract]
Schedule of significant components of deferred tax assets	Deferred tax assets and liabilities reflect the net tax effects of net operating loss and tax credit carryovers and the temporary differences between the carrying amounts of assets and liabilities for financial reporting and the amounts used for income tax purposes. Significant components of the Company's deferred tax assets are as follows: As of December 31, 2021 2020 Deferred tax assets: Net operating losses $ 143,732 $ 75,149 Research and other credits 2,178 2,178 Stock based compensation 3,354 3,256 In-Process research and development 1,132 1,193 Other 230 665 Total deferred tax assets 150,626 82,441 Valuation allowance (150,626 ) (82,441 ) Net deferred tax assets $ - $ -
Schedule of reconciliation of the statutory tax rates and the effective tax rates	A reconciliation of the statutory tax rates and the effective tax rates for the years ended December 2021 and 2020 is as follows: Year Ended December 31, 2021 2020 Statutory rate 21.0 % 21.0 % Valuation allowance (28.5 )% (27.9 )% Nondeductible stock compensation 0.4 % - % Other 7.1 % 6.9 % Effective tax rate - % - %
Reconciliation of beginning and ending amount of unrecognized tax benefits	A reconciliation of the beginning and ending amount of unrecognized tax benefits is as follows: Balance at December 31, 2019 1,060 Additions based on tax positions related to prior year - Additions based on tax positions related to current year - Balance at December 31, 2020 1,060 Additions based on tax positions related to prior year - Additions based on tax positions related to current year - Balance at December 31, 2021 $ 1,060

Organization and Description _2

Organization and Description of Business (Details) - USD ($) $ in Thousands	2 Months Ended	12 Months Ended
	Feb. 28, 2022	Dec. 31, 2021	Dec. 31, 2020
Cash and cash equivalents		$ 70,016	$ 67,737
Accounts payable and accrued expenses		64,600
Capital commitments		63,400
Total proceeds		$ 159,915	$ 139,760
Controlled Equity OfferingSM Sales Agreement [Member] | Subsequent Event [Member]
Company issued shares	1,301,548
Total proceeds	$ 3,700

Summary of Significant Accoun_4

Summary of Significant Accounting Policies (Narrative) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2021USD ($)	Dec. 31, 2020USD ($)
Summary of Significant Accounting Policies [Line Items]
Number of operating segments	1
KPM and Telcon [Member]
Summary of Significant Accounting Policies [Line Items]
License Revenue	$ 3.6	$ 0.3

Summary of Significant Accoun_5

Summary of Significant Accounting Policies (Potentially Dilutive Securities) (Details) - shares	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computations of diluted net loss per common share	4,972,130	3,779,387
Options to purchase common stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computations of diluted net loss per common share	4,429,906	3,728,149
Warrants to purchase common stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computations of diluted net loss per common share	31,238	51,238
Convertible Debt [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computations of diluted net loss per common share	510,986

License Revenue (Narrative) (De

License Revenue (Narrative) (Details) - KPM and Telcon [Member] - USD ($) $ in Millions	3 Months Ended			12 Months Ended
	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Dec. 31, 2021	Dec. 31, 2020
Upfront license Payment	$ 6		$ 6
Milestone license payments		$ 14
Description of licensing agreement				the Company will supply lenzilumab to the Licensee for a minimum of 7.5 years at a cost-plus basis from an existing or future manufacturer.
Upfront payment	$ 4.5		$ 4.5
Revenue recognized performance obligation description of payment				over the 29-month period through March of 2023 (the “Performance Period”), the expected period over which the Company conservatively expects the Services to be performed with approval in the Territory expected by the end of March 2023.
License revenue				$ 3.6	$ 0.3

License Revenue (Schedule of co

License Revenue (Schedule of contract liability) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021		Dec. 31, 2020
License Revenue
Balance at Beginning	$ 4,216
Additions	4,542	[1]	4,528	[2]
Deductions for performance obligations satisfied:
In current period	(1,721)		(312)
In prior period	(1,874)
Balance at Ending	$ 5,163		$ 4,216
[1]	Milestone payment of $6.0 million (or $4.5 million net of withholding taxes and other fees and royalties).
[2]	Up-front license fee of $6.0 million (or $4.5 million net of withholding taxes and other fees and royalties).

Accrued Expenses (Details)

Accrued Expenses (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Accrued Liabilities, Current [Abstract]
Accrued contract manufacturing-related	$ 16,174
Accrued milestone and royalties	2,736	2,368
Accrued clinical trial-related	160
Accrued compensation-related	44	530
Accrued other	768	277
Total accrued expenses	$ 19,882	$ 3,175

Debt (Narrative) (Details)

Debt (Narrative) (Details) - USD ($) $ / shares in Units, $ in Thousands

Mar. 10, 2021

Apr. 02, 2020

Mar. 13, 2020

Nov. 12, 2019

Jun. 30, 2020

Apr. 30, 2020

Mar. 19, 2020

Sep. 19, 2018

Jun. 30, 2020

Dec. 31, 2021

Dec. 31, 2020

Apr. 30, 2020

Apr. 30, 2020

Jun. 30, 2020

Mar. 29, 2021

Aug. 31, 2019

Jun. 28, 2019

Apr. 23, 2019

Jun. 30, 2016

Debt Instrument [Line Items]

Debt discount amortization

$ 562

$ 706

Proceeds from convertible debt

467

Debt issue discount

159

Converted principal amount

4,316

Secured Term Loan Facility [Member]

Debt Instrument [Line Items]

Debt instrument amount

$ 80,000

Interest expense debt

$ 2,300

Conversion price

$ 19.57

Drew amount

$ 25,000

Net proceeds

$ 24,400

Net Lenzilumab Product Revenue

$ 100,000

Prepayment percentage rate of the amounts borrowed, if the prepayment occurs on or prior to March 29, 2022

2.00%

Prepayment percentage rate of the amounts borrowed, if the prepayment occurs after March 29, 2022 and before March 29, 2023

1.50%

Prepayment percentage rate of the amounts borrowed, if the prepayment occurs after March 29, 2023 and before March 29, 2024

1.00%

Base interest rate

8.75%

9.00%

Floating interest rate, deduction

3.25%

Base interest rate reduction, basis points

0.25%

Unrestricted cash

$ 10,000

Convertible notes aggregate principal amount

250,000

Unrestricted net cash proceeds

$ 100,000

End of term fee percentage

6.75%

Secured Term Loan Facility [Member] | Minimum [Member]

Debt Instrument [Line Items]

Net Lenzilumab Product Revenue

$ 250,000

Converted principal amount

5,000

Secured Term Loan Facility [Member] | Maximum [Member]

Debt Instrument [Line Items]

Net Lenzilumab Product Revenue

350,000

Converted principal amount

10,000

Advance Notes [Member]

Debt Instrument [Line Items]

Debt discount amortization

$ 800

Second tranche [Member] | Secured Term Loan Facility [Member] | Minimum [Member]

Debt Instrument [Line Items]

Drew amount

25,000

Second tranche [Member] | Secured Term Loan Facility [Member] | Maximum [Member]

Debt Instrument [Line Items]

Drew amount

35,000

Third tranche [Member] | Secured Term Loan Facility [Member]

Debt Instrument [Line Items]

Drew amount

$ 20,000

2019 Bridge Notes [Member]

Debt Instrument [Line Items]

Term loan interest rate

7.00%

Debt instrument amount

$ 1,700

Interest expense debt

$ 100

2019 Bridge Notes [Member] | November Bridge Notes [Member]

Debt Instrument [Line Items]

Interest rate

7.00%

7.00%

7.00%

7.00%

Debt instrument amount

$ 350

$ 350

$ 350

$ 350

Maturity Date

Dec. 31, 2020

Dec. 31, 2020

2019 Bridge Notes [Member] | November Bridge Notes [Member] | Cheval Holdings [Member]

Debt Instrument [Line Items]

Debt instrument amount

$ 250

2019 Bridge Notes [Member] | Bona fide financing [Member]

Debt Instrument [Line Items]

Proceeds from advance notes

10,000

2019 Bridge Notes [Member] | Chief Executive Officer [Member]

Debt Instrument [Line Items]

Debt instrument amount

200

2019 Bridge Notes [Member] | Cameron Durrant [Member] | November Bridge Notes [Member]

Debt Instrument [Line Items]

Debt instrument amount

$ 100

2019 Bridge Notes [Member] | Cheval [Member] | November Bridge Notes [Member]

Debt Instrument [Line Items]

Debt instrument amount

$ 100

100

100

2019 Bridge Notes [Member] | Nomis Bay [Member] | November Bridge Notes [Member]

Debt Instrument [Line Items]

Debt instrument amount

$ 250

$ 250

$ 250

2019 Bridge Notes [Member] | Nomis Bay LTD [Member]

Debt Instrument [Line Items]

Debt instrument amount

750

2019 Bridge Notes [Member] | Cameron Durrant [Member]

Debt Instrument [Line Items]

Debt instrument amount

$ 750

2019 Bridge Notes [Member] | Bona Fide Financing Transaction [Member]

Debt Instrument [Line Items]

Proceeds from advance notes

$ 3,000

2018 Convertible Notes Payable [Member] | Non Qualified Financing [Member]

Debt Instrument [Line Items]

Proceeds from convertible debt

$ 10,000

Conversion price

$ 2.25

$ 2.25

$ 2.25

Black Horse Capital LP [Member] | Convertible Promissory Note [Member]

Debt Instrument [Line Items]

Term loan interest rate

7.00%

Debt instrument amount

$ 2,500

2019 Convertible Notes Payable [Member]

Debt Instrument [Line Items]

Term loan interest rate

7.50%

Debt instrument amount

$ 1,300

Interest expense debt

200

Proceeds from convertible debt

$ 4,300

Issuance of common stock upon note conversions shares

2,397,916

2019 Convertible Notes Payable [Member] | Cheval. Dr. Dale Chappell [Member]

Debt Instrument [Line Items]

Issuance of common stock upon note conversions shares

316,666

2019 Convertible Notes Payable [Member] | Non Qualified Financing [Member]

Debt Instrument [Line Items]

Proceeds from convertible debt

$ 10,000

Conversion price

6.25

$ 6.25

$ 6.25

2019 Convertible Notes Payable [Member] | Advance Notes [Member]

Debt Instrument [Line Items]

Common stock conversion price

6.25

2018 Convertible Notes Payable [Member] | Advance Notes [Member]

Debt Instrument [Line Items]

Common stock conversion price

$ 2.25

Intrinsic value of this beneficial conversion feature

$ 1,800

2020 Convertible Redeemable Notes [Member]

Debt Instrument [Line Items]

Notes payable to vendors

$ 518,333

Term loan interest rate

7.00%

Debt discount amortization

100

Interest expense debt

200

Debt instrument redemption description

The notes could be redeemed by the Company at any time before the 270th day following issuance, at a redemption price equal to the principal and accrued but unpaid interest on the notes to the date of redemption, plus a premium that increases on day 61 and day 121 from the issuance date. Accordingly, the notes were repaid in June 2020 with proceeds from the Private Placement, and the notes were extinguished.

Fair value of convertible notes

$ 0

2020 Convertible Redeemable Notes [Member] | Tranche One [Member]

Debt Instrument [Line Items]

Maturity Date

Mar. 13, 2021

Debt issue discount

$ 33,000

2020 Convertible Redeemable Notes [Member] | Tranche Two [Member]

Debt Instrument [Line Items]

Maturity Date

Mar. 19, 2021

Debt issue discount

$ 18,833

Notes Payable To Vendors [Member]

Debt Instrument [Line Items]

Interest rate

10.00%

Notes payable to vendors

$ 1,200

Notes Payable To Vendors [Member] | 2019 Bridge Notes [Member]

Debt Instrument [Line Items]

Debt instrument amount

$ 500

Notes Payable To Vendors [Member] | 2018 Convertible Notes Payable [Member]

Debt Instrument [Line Items]

Interest expense debt

$ 800

Debt (Schedule of Outstanding F

Debt (Schedule of Outstanding Future Payments Associated Company's Term Loan) (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Debt Disclosure [Abstract]
2022	$ 2,218
2023	10,800
2024	13,671
2025	5,153
Total payments	31,842
Less amount representing interest	(5,155)
Notes payable, gross	26,687
Less: Unamortized portion of EOT charge	(1,264)
Less: Unamortized discount on notes payable	(159)
Less: Unamortized debt issuance costs	(258)
Long-term debt	25,006
Less current portion
Long-term debt, net of current portion	$ 25,006

Warrants to Purchase Common S_2

Warrants to Purchase Common Stock (Details) - USD ($) $ / shares in Units, $ in Thousands	Sep. 14, 2020	Jun. 30, 2021	May 20, 2020	Apr. 22, 2020	Jun. 30, 2016	Dec. 31, 2021	Jul. 30, 2020	Dec. 04, 2015	Jun. 19, 2013
Class of Warrant or Right [Line Items]
Issuance of warrant to purchase shares of common stock						31,238
Vesting period						3 years
Warrant [Member]
Class of Warrant or Right [Line Items]
Issuance of warrant to purchase shares of common stock								25,000	1,238
Exercise price of warrants issued (in dollars per share)								$ 146.60	$ 484.80
Warrant [Member] | Investor Relation Services [Member]
Class of Warrant or Right [Line Items]
Issuance of warrant to purchase shares of common stock	200,000		4,000	8,000
Exercise price of warrants issued (in dollars per share)	$ 0.05		$ 0.05	$ 0.05
Term of issuance of warrant	8 years		8 years	8 years
Vesting period	2 years		2 years	2 years
Proceeds from warrants excercises	$ 10,000		$ 200	$ 400
Warrant [Member] | Manufacturing Consulting Services [Member]
Class of Warrant or Right [Line Items]
Issuance of warrant to purchase shares of common stock			30,000
Exercise price of warrants issued (in dollars per share)			$ 4.30
Term of issuance of warrant			10 years
Savant Warrant [Member]
Class of Warrant or Right [Line Items]
Issuance of warrant to purchase shares of common stock					40,000		10,909
Exercise price of warrants issued (in dollars per share)					$ 11.25
Term of issuance of warrant					5 years
Percentage of warrant exercisable					25.00%
Number of warrants exercised		20,000

Commitments and Contingencies (

Commitments and Contingencies (Details) - USD ($) $ in Thousands	1 Months Ended		6 Months Ended	12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Dec. 31, 2021	Dec. 31, 2020
Other Commitments [Line Items]
Commitments remaining, 2022				$ 63,400
Commitments remaining, 2023				4,600
Commitments remaining, thereafter				7,400
Rent expense	$ 1,200	$ 1,200
Expiration date	Aug. 31, 2021	Sep. 30, 2022
Lease costs				14	$ 3
Future minimum lease payments				$ 11
Eversana Agreement [Member]
Other Commitments [Line Items]
Payment requested for services rendered			$ 4,000

Stockholders' Equity (Narrative

Stockholders' Equity (Narrative) (Details) - USD ($) $ / shares in Units, $ in Thousands	May 03, 2021	Mar. 30, 2021	Sep. 17, 2020	Jun. 30, 2020	May 03, 2021	Sep. 11, 2020	Dec. 31, 2021	Dec. 31, 2020	Jul. 27, 2020	Jun. 02, 2020
Class of Stock [Line Items]
Common Stock, shares authorized upon the completion of the IPO						225,000,000	225,000,000	225,000,000
Common stock, par value							$ 0.001	$ 0.001
Total proceeds							$ 159,915	$ 139,760
Common stock, shares outstanding							64,027,629	51,626,508
Options granted							1,444,176	985,164
Private Placement [Member]
Class of Stock [Line Items]
Common stock, par value										$ 4.35
Total proceeds				$ 71,800
Company issued shares				16,505,743
2020 Underwritten Public Offering [Member] | J.P. Morgan Securities LLC and Jefferies LLC [Member]
Class of Stock [Line Items]
Shares issued in public offering			8,000,000
Shares issued to underwriters			1,200,000
2020 Partial Underwritten Public Offering [Member]
Class of Stock [Line Items]
Shares issued in public offering			9,200,000
Proceeds from issued in public offering			$ 78,200
Controlled Equity OfferingSM Sales Agreement [Member] | Cantor Fitzgerald & Co. [Member]
Class of Stock [Line Items]
Total proceeds							$ 65,700
Company issued shares							6,408,087
2021 Underwritten Public Offering [Member]
Class of Stock [Line Items]
Shares issued in public offering					5,427,017
Shares issued to underwriters	427,017
Proceeds from issued in public offering					$ 100,400
Proceeds from sale of shares after offering costs					$ 94,200
2021 Underwritten Public Offering [Member] | Jefferies LLC [Member]
Class of Stock [Line Items]
Shares issued in public offering		5,000,000
Total number of shares offered to underwriters		750,000
Maximum [Member]
Class of Stock [Line Items]
Common stock, shares outstanding						210,900,000
Maximum [Member] | Controlled Equity OfferingSM Sales Agreement [Member] | Cantor Fitzgerald & Co. [Member]
Class of Stock [Line Items]
Remaing value of shares available for sale							$ 32,300
Proceeds from sale and issuance of common stock							$ 100,000
Minimum [Member]
Class of Stock [Line Items]
Common stock, shares outstanding						42,200,000
2020 Equity Plan [Member]
Class of Stock [Line Items]
Reverse stock split						1-for-5
Shares available for future grant						7,000,000	5,004,035		7,000,000
Percentage of outstanding shares approved equity plan									63.00%

Stockholders' Equity (Schedule

Stockholders' Equity (Schedule of Shares of Common Stock Reserved for Issuance) (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Warrants to purchase common stock	31,238
Total common stock reserved for future issuance	9,465,179
Vesting period	3 years
Total fair value of options vested	$ 2.3	$ 2.2
Weighted-average fair value of options granted during the period	$ 10.32	$ 7.35
Weighted-average period	2 years 3 months 18 days
Unrecognized compensation expense	$ 12.2
2020 Equity Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Option outstanding	1,962,489
Available for future grants	5,004,035
Vesting period expiration	10 years
2012 Equity Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Option outstanding	2,467,417

Stockholders' Equity (Stock Opt

Stockholders' Equity (Stock Option Activity) (Details) - USD ($) $ / shares in Units, $ in Thousands		12 Months Ended
		Dec. 31, 2021	Dec. 31, 2020
Number of Shares
Balance at the beginning of the period (in shares)		3,732,149	3,176,336
Options granted (in shares)		1,444,176	985,164
Options exercised (in shares)		(582,936)	(429,330)
Options cancelled (forfeited) (in shares)		(81,711)
Options cancelled (expired) (in shares)		(81,772)	(21)
Balance at the end of the period (in shares)		4,429,906	3,732,149
Options vested and expected to vest at the end of the period (in shares)		4,281,658
Options exercisable (in shares)		2,951,257
Weighted-Average Exercise Price (per share)
Balance at the beginning of the period (in dollars per share)	[1]	$ 5.57	$ 4.75
Options granted (in dollars per share)	[1]	12.58	7.35
Options exercised (in dollars per share)	[1]	3.98	3.55
Options cancelled (forfeited) (in dollars per share)	[1]	7.09
Options cancelled (expired) (in dollars per share)	[1]	13.71	58.40
Balance at the ending of the period (in dollars per share)	[1]	7.89	$ 5.57
Options vested and expected to vest at the end of the period (in dollars per share)	[1]	7.77
Options exercisable (in dollars per share)	[1]	$ 6.08
Weighted-Average Remaining Contractual Term (in years)
Balance at the end of the period		7 years 4 months 24 days
Options vested and expected to vest at the end of the period		7 years 3 months 18 days
Options exercisable		6 years 8 months 12 days
Aggregate Intrinsic Value (in thousands)
Balance at the end of the period	[2]	$ 1,087
Options vested and expected to vest at the end of the period	[2]	1,084
Options exercisable	[2]	$ 1,017
[1]	The weighted average price per share is determined using exercise price per share for stock options.
[2]	The aggregate intrinsic value is calculated as the difference between the exercise price of the option and the fair value of the Company’s common stock for in-the-money options at December 31, 2021.

Stockholders' Equity (Options O

Stockholders' Equity (Options Outstanding and Exercisable By Price Range) (Details)	12 Months Ended
	Dec. 31, 2021$ / sharesshares
Stock Options Outstanding
Number of Shares | shares	4,429,906
Weighted Average Remaining Contractual Life	7 years 4 months 24 days
Weighted Average Exercise Price (in dollars per share)	$ 7.89
Stock Options Exercisable
Number of Shares | shares	2,951,257
Weighted Average Exercise Price Per Share (in dollars per share)	$ 6.08
Exercise Price Range From $1.90 - $2.25 [Member]
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]
Exercise Price, low end of range (in dollars per share)	1.90
Exercise Price, high end of range (in dollars per share)	$ 2.25
Stock Options Outstanding
Number of Shares | shares	216,795
Weighted Average Remaining Contractual Life	8 years
Weighted Average Exercise Price (in dollars per share)	$ 2.16
Stock Options Exercisable
Number of Shares | shares	169,069
Weighted Average Exercise Price Per Share (in dollars per share)	$ 2.14
Exercise Price Range 3.33 [Member]
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]
Exercise Price, low end of range (in dollars per share)	$ 3.33
Stock Options Outstanding
Number of Shares | shares	1,894,168
Weighted Average Remaining Contractual Life	6 years 2 months 4 days
Weighted Average Exercise Price (in dollars per share)	$ 3.33
Stock Options Exercisable
Number of Shares | shares	1,894,168
Weighted Average Exercise Price Per Share (in dollars per share)	$ 3.33
Exercise Price Range From $3.50 - $9.65 [Member]
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]
Exercise Price, low end of range (in dollars per share)	3.50
Exercise Price, high end of range (in dollars per share)	$ 9.65
Stock Options Outstanding
Number of Shares | shares	987,674
Weighted Average Remaining Contractual Life	9 years 14 days
Weighted Average Exercise Price (in dollars per share)	$ 6.92
Stock Options Exercisable
Number of Shares | shares	328,349
Weighted Average Exercise Price Per Share (in dollars per share)	$ 7.33
Exercise Price Range From $16.90 - $16.90 [Member]
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]
Exercise Price, low end of range (in dollars per share)	10.64
Exercise Price, high end of range (in dollars per share)	$ 15.90
Stock Options Outstanding
Number of Shares | shares	274,425
Weighted Average Remaining Contractual Life	9 years 2 months 1 day
Weighted Average Exercise Price (in dollars per share)	$ 14.22
Stock Options Exercisable
Number of Shares | shares	113,174
Weighted Average Exercise Price Per Share (in dollars per share)	$ 12.86
Exercise Price Range $16.07 [Member]
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]
Exercise Price, low end of range (in dollars per share)	$ 16.07
Stock Options Outstanding
Number of Shares | shares	733,240
Weighted Average Remaining Contractual Life	8 years 2 months 15 days
Weighted Average Exercise Price (in dollars per share)	$ 16.07
Stock Options Exercisable
Number of Shares | shares	183,310
Weighted Average Exercise Price Per Share (in dollars per share)	$ 16.07
Exercise Price Range From $16.90 - $20.00 [Member]
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]
Exercise Price, low end of range (in dollars per share)	16.90
Exercise Price, high end of range (in dollars per share)	$ 20
Stock Options Outstanding
Number of Shares | shares	293,604
Weighted Average Remaining Contractual Life	5 years 4 months 24 days
Weighted Average Exercise Price (in dollars per share)	$ 17.19
Stock Options Exercisable
Number of Shares | shares	258,187
Weighted Average Exercise Price Per Share (in dollars per share)	$ 16.96
Exercise Price Range $20.68 [Member]
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]
Exercise Price, low end of range (in dollars per share)	$ 20.68
Stock Options Outstanding
Number of Shares | shares	30,000
Weighted Average Remaining Contractual Life	9 years 5 months 4 days
Weighted Average Exercise Price (in dollars per share)	$ 20.68
Stock Options Exercisable
Number of Shares | shares	5,000
Weighted Average Exercise Price Per Share (in dollars per share)	$ 20.68

Stockholders' Equity (Fair Valu

Stockholders' Equity (Fair Value Assumptions) (Details)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Expected volatility, minimum (as a percent)	104.00%	95.00%
Expected volatility, maximum (as a percent)	109.00%	111.00%
Risk-free interest rate, minimum (as a percent)	0.98%	0.28%
Risk-free interest rate, maximum (as a percent)	1.35%	1.57%
Expected dividend yield (as a percent)	0.00%	0.00%
Minimum [Member]
Expected term	5 years	5 years
Maximum [Member]
Expected term	6 years	6 years

Stockholders' Equity (Stock-Bas

Stockholders' Equity (Stock-Based Compensation Expense Recognized) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation expense	$ 5,368	$ 2,110
General And Administrative Expense [Member]
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation expense	4,028	1,773
Research And Development Expense [Member]
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation expense	$ 1,340	$ 337

Income Taxes (Narrative) (Detai

Income Taxes (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2018
Increase (decrease) in valuation allowance	$ 68.2	$ 25
Federal Statutory Income Tax Rate	21.00%	21.00%
Income tax expense	$ 21.6
Income tax benefit	$ 21.6
Minimum [Member]
Federal Statutory Income Tax Rate	21.00%
Maximum [Member]
Federal Statutory Income Tax Rate	35.00%
Internal Revenue Service I R S [Member]
Net operating loss carryforwards	$ 166.2		$ 346.9
Internal Revenue Service I R S [Member] | Research [Member]
Tax credit carryforwards	$ 1.3
Internal Revenue Service I R S [Member] | Minimum [Member]
Expiration year	Dec. 31, 2022
Internal Revenue Service I R S [Member] | Minimum [Member] | Research [Member]
Expiration year	Dec. 31, 2022
Internal Revenue Service I R S [Member] | Maximum [Member]
Expiration year	Dec. 31, 2037
Internal Revenue Service I R S [Member] | Maximum [Member] | Research [Member]
Expiration year	Dec. 31, 2035
State And Local Jurisdiction [Member]
Net operating loss carryforwards	$ 522.5
State And Local Jurisdiction [Member] | Research [Member]
Tax credit carryforwards	$ 2.2
State And Local Jurisdiction [Member] | Minimum [Member]
Expiration year	Dec. 31, 2028
State And Local Jurisdiction [Member] | Maximum [Member]
Expiration year	Dec. 31, 2041

Income Taxes (Significant Compo

Income Taxes (Significant Components of Deferred Tax Assets) (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Deferred tax assets:
Net operating losses	$ 143,732	$ 75,149
Research and other credits	2,178	2,178
Stock based compensation	3,354	3,256
In-Process research and development	1,132	1,193
Other	230	665
Total deferred tax assets	150,626	82,441
Valuation allowance	(150,626)	(82,441)
Net deferred tax assets

Income Taxes (Reconciliation of

Income Taxes (Reconciliation of the Statutory Tax Rates and Effective Tax Rates) (Details)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Reconciliation of the statutory tax rates and the effective tax rates
Statutory rate	21.00%	21.00%
Valuation allowance	(28.50%)	(27.90%)
Nondeductible stock compensation	0.40%
Other	7.10%	6.90%
Effective tax rate

Income Taxes (Reconciliation _2

Income Taxes (Reconciliation of Beginning and Ending Amount of Unrecognized Tax Benefits) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Reconciliation of the beginning and ending amount of unrecognized tax benefits
Balance at the beginning of the period	$ 1,060	$ 1,060
Additions based on tax positions related to prior year
Additions based on tax positions related to current year
Balance at the end of the period	$ 1,060	$ 1,060

Employee Benefit Plan (Details)

Employee Benefit Plan (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2021USD ($)
Retirement Benefits [Abstract]
Employer contributions	$ 23,000

Litigation (Details)

Litigation (Details) - USD ($) $ in Millions	1 Months Ended
	Feb. 24, 2022	Dec. 17, 2021
Avid Arbitration [Member]
Loss Contingency Damages Sought Value		$ 20.5
Loss Contingency Damages Paid Value		$ 10.6
Two Plaintiffs [Member] | Alliance Texas Holding Case [Member] | Subsequent Event [Member]
Loss contingency settlement agreement date	February 24, 2022
Two Plaintiffs [Member] | Alliance Texas Holding Case [Member] | Subsequent Event [Member] | Minimum [Member]
Loss contingency settlement percentage	10.00%

License and Collaboration Agr_2

License and Collaboration Agreements (Details) - USD ($) $ in Millions	6 Months Ended	12 Months Ended
	Jun. 30, 2020	Dec. 31, 2021	Dec. 31, 2020
Kite Agreement [Member]
Amount paid in license agreement		$ 0	$ 2
Mayo Agreement [Member]
Amount paid in license agreement	$ 0.2

Subsequent Events (Details)

Subsequent Events (Details) - USD ($) $ in Thousands	1 Months Ended	2 Months Ended	12 Months Ended
	Feb. 24, 2022	Feb. 28, 2022	Dec. 31, 2021	Dec. 31, 2020
Subsequent Event [Line Items]
Total proceeds			$ 159,915	$ 139,760
Subsequent Event [Member] | Alliance Texas Holding Case [Member] | Two Plaintiffs [Member]
Subsequent Event [Line Items]
Loss contingency settlement agreement date	February 24, 2022
Controlled Equity OfferingSM Sales Agreement [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Company issued shares		1,301,548
Total proceeds		$ 3,700