Humanigen (HGENQ) 10-K 30 Mar 23 2022 FY Annual report Financial data

Document And Entity Information

Document And Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2022	Mar. 16, 2023	Jun. 30, 2022
Document Information Line Items
Entity Registrant Name	HUMANIGEN, INC
Trading Symbol	HGEN
Document Type	10-K
Current Fiscal Year End Date	--12-31
Entity Common Stock, Shares Outstanding		119,080,135
Entity Public Float			$ 84,020,909
Amendment Flag	false
Entity Central Index Key	0001293310
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Non-accelerated Filer
Entity Well-known Seasoned Issuer	No
Document Period End Date	Dec. 31, 2022
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	FY
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Shell Company	false
ICFR Auditor Attestation Flag	false
Document Annual Report	true
Document Transition Report	false
Entity File Number	001-35798
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	77-0557236
Entity Address, Address Line One	830 Morris Turnpike
Entity Address, Address Line Two	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
Security Exchange Name	NASDAQ
Entity Interactive Data Current	Yes
Auditor Firm ID	171
Auditor Name	HORNE LLP
Auditor Location	Ridgeland, Mississippi

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Current assets:
Cash and cash equivalents	$ 10,155	$ 70,016
Prepaid expenses and other current assets	950	955
Total current assets	11,105	70,971
Other assets	90	90
Total assets	11,195	71,061
Current liabilities:
Accounts payable	40,520	44,698
Accrued expenses	14,791	19,882
Deferred revenue	883	4,145
Total current liabilities	56,194	68,725
Non-current liabilities:
Deferred revenue	1,766	1,018
Long-term debt		25,006
Total liabilities	57,960	94,749
Commitments and contingencies (Note 7)
Stockholders’ equity (deficit):
Common stock, $0.001 par value: 225,000,000 shares authorized at December 31, 2022 and December 31, 2021; 119,080,135 and 64,027,629 shares issued and outstanding at December 31, 2022 and December 31, 2021, respectively	119	64
Additional paid-in capital	634,925	587,327
Accumulated deficit	(681,809)	(611,079)
Total stockholders’ deficit	(46,765)	(23,688)
Total liabilities and stockholders’ deficit	$ 11,195	$ 71,061

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parentheticals) - $ / shares	Dec. 31, 2022	Dec. 31, 2021
Statement of Financial Position [Abstract]
Common stock, par value (in Dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized	225,000,000	225,000,000
Common stock, shares issued	119,080,135	64,027,629
Common stock, shares outstanding	119,080,135	64,027,629

Consolidated Statements of Oper

Consolidated Statements of Operations (Unaudited) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Revenue:
Total revenue	$ 2,514	$ 3,595
Operating expenses:
Research and development	55,210	213,115
General and administrative	15,608	23,252
Total operating expenses	70,818	236,367
Loss from operations	(68,304)	(232,772)
Other income (expense):
Interest expense	(2,918)	(2,264)
Other income (expense), net	492	(1,613)
Net loss	$ (70,730)	$ (236,649)
Basic and diluted net loss per common share (in Dollars per share)	$ (0.79)	$ (4.04)
Weighted average common shares outstanding used to calculate basic and diluted net loss per common share (in Shares)	89,236,429	58,533,637
License revenue
Revenue:
Total revenue	$ 2,514	$ 3,595

Consolidated Statements of Op_2

Consolidated Statements of Operations (Unaudited) (Parentheticals) - $ / shares	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Income Statement [Abstract]
Diluted net loss per common share (in Dollars per share)	$ (0.79)	$ (4.04)
Weighted average common shares outstanding used to calculate diluted net loss per common share (in Shares)	89,236,429	58,533,637

Consolidated Statements of Stoc

Consolidated Statements of Stockholders’ Equity (Deficit) - USD ($) $ in Thousands	Common Stock	Additional Paid-In Capital	Accumulated Deficit	Total
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 (in Shares)	11,835,104			6,408,087
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 (in 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
Issuance of common stock, net of expenses	$ 55	41,788		41,843
Issuance of common stock, net of expenses (in Shares)	55,052,506
Stock-based compensation expense		5,810		5,810
Net loss			(70,730)	(70,730)
Balances at Dec. 31, 2022	$ 119	$ 634,925	$ (681,809)	$ (46,765)
Balances (in Shares) at Dec. 31, 2022	119,080,135

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Operating activities:
Net loss	$ (70,730)	$ (236,649)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock based compensation expense	5,810	5,368
Non-cash interest expense related to debt financing		562
Changes in operating assets and liabilities:
Prepaid expenses and other assets	5	(480)
Accounts payable	(4,178)	29,332
Accrued expenses	(5,091)	16,875
Deferred revenue	(2,514)	947
Net cash used in operating activities	(76,698)	(184,045)
Financing activities:
Net proceeds from issuance of common stock	41,843	159,915
Proceeds from exercise of stock options		1,965
Net proceeds from issuance of long-term debt		24,444
Principal payments on long-term debt	(25,006)
Net cash provided by financing activities	16,837	186,324
Net increase (decrease) in cash and cash equivalents	(59,861)	2,279
Cash and cash equivalents, beginning of period	70,016	67,737
Cash and cash equivalents, end of period	10,155	70,016
Supplemental cash flow disclosure:
Cash paid for interest	1,319	1,519
Supplemental disclosure of non-cash investing and financing activities:
Issuance of stock options in lieu of cash compensation		$ 168

Organization and Description of

Organization and Description of Business	12 Months Ended
	Dec. 31, 2022
Organization and Description of Business [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 ® ® In July 2022, topline 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, were released. The study was sponsored and funded by the National Institutes of Health (“NIH”) and evaluated lenzilumab in combination with remdesivir, compared to placebo and remdesivir, in hospitalized COVID-19 patients. The topline results showed the trial did not achieve statistical significance on the primary endpoint, although the topline results did indicate that lenzilumab demonstrated a positive trend in mortality. A global group of leading institutions and research networks has indicated interest in including lenzilumab in their large-scale, multinational studies of COVID-19, pending an uptick in ICU admissions. Tocilizumab and baricitinib demonstrated mortality benefit following inclusion in REMAP-CAP and RECOVERY, despite having failed to do so in smaller studies. Pursuant to the Company’s previously reported strategic realignment plan, the Company is developing lenzilumab in chronic myelomonocytic leukemia (“CMML”), a rare blood cancer, for which the PREACH-M study is already underway, and is continuing its plans for the RATinG study in acute graft versus host disease (“aGvHD”) that occurs in patients undergoing bone marrow transplant, as these studies are majority funded by its partners. The Company anticipates the first patient dosing in the RATinG study to occur in the second quarter of 2023. These studies are majority funded by the Company’s partners. A leading network of centers, The Mayo Clinics, is currently progressing with an investigator-initiated trial (“IIT”) of lenzilumab in combination with CAR-T therapies. The Company is also developing iFab, an EpAh-3 targeted monoclonal antibody, currently in Phase 1 development, as part of an antibody drug conjugate (“ADC”), for certain solid tumors. Under the realignment plan, the Company has deemphasized the deployment of resources for the development of lenzilumab for COVID-19 and currently does not plan to pursue regulatory pathways, unless further data from ACTIV-5/BET-B or a future large-scale study merit such an approach. The Named Patient program in select European Countries has been terminated. With the exception of the one lenzilumab batch in process, the Company has discontinued the manufacturing of lenzilumab and is consolidating the remaining inventory of lenzilumab bulk drug substance and drug product in a central location for potential future use. 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, 2022 and 2021 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. As of December 31, 2022, the Company had cash and cash equivalents of $10.2 million. Considering the Company’s current cash resources and its current and expected levels of operating expenses for the next twelve months, which includes combined accounts payable and accrued expenses recorded in the Company’s consolidated balance sheets as of December 31, 2022 of $55.3 million, certain of which are in dispute, and manufacturing commitments of $2.6 million for 2023, with no significant commitments thereafter (see Note 7 below), the Company requires additional capital to fund the Company’s planned operations. The Company intends to seek to defer payments, negotiate lower amounts or pursue other courses of action for certain amounts owed to manufacturing and other partners at December 31, 2022. In order to remain a going concern and execute its strategic realignment plan, the Company must successfully renegotiate these amounts owed, and settle disputes, including current and potential future arbitration and litigation. The Company recently engaged SC&H Capital, an affiliate of SC&H Group, (“SC&H”), to advise the Company on exploration of strategic options to maximize value around its development pipeline. The Company has not set a timetable for the conclusion of its review of strategic alternatives, and there can be no assurance that this process will result in any transaction. The Company also 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, 2022
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies Basis of Presentation and Use of Estimates The accompanying Consolidated Financial Statements have been prepared in accordance with US generally accepted accounting principles (“US 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 US 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 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 $2.5 million and $3.6 million in revenue for the years ended December 31, 2022 and 2021, 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. 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. 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. 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 potentially 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, 2022 2021 Options to purchase common stock 7,472,056 4,429,906 Warrants to purchase common stock 31,238 31,238 Convertible debt - 510,986 7,503,294 4,972,130 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 issued by the Financial Accounting Standards Board (“FASB”), including its Emerging Issues Task Force, the American Institute of Certified Public Accountants, and the Securities and Exchange Commission (the “SEC”) did not or are not believed by management to have a material impact on the Company's present or future financial statements.

License Revenue

License Revenue	12 Months Ended
	Dec. 31, 2022
License Revenue [Abstract]
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 US, 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) was initially 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 expected the Services to be performed with approval in the Territory originally 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. During the quarter ended September 30, 2022, the performance period was reevaluated, and the estimated end date of the performance period was adjusted to December 31, 2025. The change in estimate resulted in a decrease of $0.8 million in quarterly license revenue as compared to amounts that would have been recorded under the previous timeline. In the years ended December 21, 2022 and 2021, the Company has recognized license revenue totaling approximately $2.5 million and $3.6 million, respectively. Prospective periods will reflect the impact of this change in estimate. 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 $2.6 million, $0.9 million of which represented the current portion, was recorded on the Consolidated Balance Sheets as deferred revenue as of December 31, 2022 related to the South Korea agreement. There were no contract asset or deferred contract acquisition costs as of December 31, 2022 associated with the South Korea agreement. The following table presents changes in the Company’s contract liability for the years ended December 31, 2022 and 2021 (in thousands): Balance at January 1, 2021 $ 4,216 Additions (1) 4,542 Deductions for performance obligations satisfied: In current period (1,721 ) In prior period (1,874 ) Balance at December 31, 2021 5,163 Deductions for performance obligations satisfied: In current period (2,514 ) Balance at December 31, 2022 $ 2,649 (1)

Accrued Expenses

Accrued Expenses	12 Months Ended
	Dec. 31, 2022
Accrued Expenses [Abstract]
Accrued Expenses	4. Accrued Expenses Accrued expenses consist of the following (in thousands): As of December 31, 2022 2021 Accrued contract manufacturing-related $ 13,325 $ 16,174 Accrued milestone and royalties 736 2,736 Accrued clinical trial-related 205 160 Accrued compensation-related 106 44 Accrued other 419 768 $ 14,791 $ 19,882

Debt

Debt	12 Months Ended
	Dec. 31, 2022
Debt Disclosure [Abstract]
Debt	5. Debt Secured Term Loan Facility On March 10, 2021, the Company executed the Loan and Security Agreement with Hercules Capital as agent for its affiliates serving as lenders thereunder (the “Term Loan”) which provided 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 Term Loan bore 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%. The Company was initially obligated to make monthly payments of accrued interest under the Term Loan commencing on the initial borrowing date and continuing to April 1, 2023, followed by monthly installments of principal and interest until March 1, 2025. In July 2022, the Company prepaid $25.0 million of outstanding principal, together with approximately $1.7 million of accrued interest, fees and other amounts, due under the Term Loan. In connection with the prepayment, the Term Loan with Hercules was terminated, and all obligations, liens and security interests under the Term Loan were released, discharged and satisfied. By retiring the Term Loan, the Company reduced future cash payments for interest and enhanced its ability to generate additional liquidity from its intellectual property by removing the loan’s collateral requirements. Interest expense related to the Term Loan, for the years ended December 31, 2022 and 2021 was approximately $2.9 million and $2.3 million, respectively, and the effective interest rate was 9.3% and 9.0%, respectively. Interest expense in the year ended December 31, 2022 included $1.2 million in unamortized loan fees recognized in connection with the loan payoff.

Warrants to Purchase Common Sto

Warrants to Purchase Common Stock	12 Months Ended
	Dec. 31, 2022
Warrants to Purchase Common Stock [Abstract]
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, 2022, these warrants were fully vested and unexercised. 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 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, 2022.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2022
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 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 Emergency Use Authorization (“EUA”) status in the US, 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 $4.5 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 Eversana has filed for arbitration to resolve this dispute. See Note 11 below for more information on this dispute. Manufacturing Agreements The Company has entered into agreements with several contract manufacturing organizations (“CMOs”) to manufacture bulk drug substance (“BDS”) and to provide fill/finish services or drug product (“DP”) for lenzilumab for a potential launch of lenzilumab in anticipation of an EUA or CMA. The Company has also entered into agreements for packaging of the drug. These agreements include upfront amounts prior to commencement of manufacturing and progress payments through the course of the manufacturing process and payments for technology transfer. The Company has amended, and in some cases canceled, certain of these agreements. In addition, the Company has sought to mitigate its financial commitments by ceasing additional manufacturing of lenzilumab in connection with its realignment plan, and more recently, it has settled its disputes with two of its CMOs. See Note 11 below for more information on these settlement agreements. As of December 31, 2022, the Company estimates that its commitments remaining to be incurred under its CMO agreements are approximately $2.6 million for 2023 with no significant commitments thereafter. In connection with the Company’s realignment to deemphasize the deployment of certain resources for the development of lenzilumab for COVID-19, with the exception of one lenzilumab batch in process at one of its CMOs, Catalent Pharma Solutions, LLC (“Catalent”), the Company has discontinued the manufacturing of lenzilumab and is consolidating the remaining inventory of lenzilumab bulk drug substance and drug product in a central location for potential future use. The Company believes it has sufficient drug product for its currently planned clinical trials. If the Company is unable to obtain regulatory approval for lenzilumab prior to the expiration of the shelf life at that time, the remaining inventory will not be available for commercial use. There is significant drug product that was in production at one of the Company’s other CMOs, Thermo Fisher Scientific, Inc. (“Thermo”), for which material has not yet been released by the Company because the batches produced are out of specification. Nonetheless, Thermo has notified the Company that they have stopped production and have recently filed a lawsuit against the Company in Delaware Superior Court for $25.9 million. The Company has filed a countersuit against Thermo for breach of contract seeking more than $37.5 million. The Company denies Thermo’s claims and assertions and intends to vigorously defend against them. See Note 11 below for more information on this dispute. Operating Leases On September 1, 2021, the Company entered into a one-year lease for a small office a building in Burlingame, California for $1,200 per month which expired on August 31, 2022. On September 1, 2022, 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, 2023. On February 3, 2022, the Company entered into an eighteen-month lease for an office in Short Hills, New Jersey for approximately $300 per month which will expire on August 31, 2023. Management determined the lease term for each of the leases to be less than 12 months, or immaterial, 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, 2022 and 2021 totaled approximately $20 thousand and $14 thousand, respectively, and are included in the Consolidated Statements of Operations. As of December 31, 2022, the Company had future minimum lease payments of approximately $15 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, 2022
Stockholders’ Equity [Abstract]
Stockholders’ Equity	8. Stockholders’ Equity 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. Controlled Equity Offering On December 31, 2020, the Company entered into a 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 the sales agent. On April 14, 2022, the Company filed a prospectus in respect of the Sales Agreement which provides the Company with the ability to offer and sell shares of common stock having an aggregate offering price of up to an additional $75.0 million. During the year ended December 31, 2022, under the Sales Agreement, the Company issued and sold 55,052,506 shares of its common stock for net proceeds of $41.8 million, after deducting fees and expenses. 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. No shares have been sold under the Sales Agreement subsequent to December 31, 2022. 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. 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, 2022, there were 1,948,135 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. 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, 2022, there were no shares available for grant under the 2012 Equity Incentive Plan. The Company has reserved the following shares of common stock for issuance as of December 31, 2022: Warrants to purchase common stock 31,238 Options: Outstanding under the 2020 Equity Incentive Plan 5,018,389 Outstanding under the 2012 Equity Incentive Plan 2,453,667 Available for future grants under the 2020 Equity Incentive Plan 1,948,135 9,451,429 Stock Option Activity The following table summarizes stock option activity for the years ended December 31, 2022 and 2021: 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, 2021 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 Granted 4,708,969 0.57 Exercised - - Cancelled (forfeited) (1,568,912 ) 2.94 Cancelled (expired) (97,907 ) 14.45 Outstanding at December 31, 2022 7,472,056 $ 4.23 7.6 $ - Options vested and expected to vest 7,237,665 $ 4.32 7.6 $ - Exercisable 3,435,577 $ 6.70 5.6 $ - ______________________ (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, 2022. The stock options outstanding and exercisable by exercise price at December 31, 2022 are as follows: Stock Options Outstanding Stock Options Exercisable Range of Exercise Prices Number of Shares Weighted- Average Remaining Contractual Life In Years Weighted- Average Exercise Price Per Share Number of Shares Weighted- Average Exercise Price Per Share $0.38 - $0.38 3,221,367 9.6 $ 0.38 0 - $1.90 - $2.99 455,915 8.1 $ 2.60 216,795 2.16 $3.33 - $3.33 1,894,168 4.8 3.33 1,894,168 3.33 $3.5 - $16.07 1,607,002 7.6 11.12 1,051,427 11.02 $16.90 - $16.90 248,604 3.4 16.90 248,604 16.90 $17.79 - $17.79 25,000 8.2 17.79 14,583 17.79 $20.00 - $20.00 20,000 8.4 20.00 10,000 20.00 7,472,056 7.6 $ 4.23 3,435,577 $ 6.70 The total fair value of options vested for the years ended December 31, 2022 and 2021 was $0.7 million and $2.3 million, respectively. 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, 2022 and 2021 was $0.47 and $10.32 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, 2022 2021 Expected term 6 years 5 - 6 years Expected volatility 104% - 109% 104% - 109% Risk-free interest rate 1.59% - 2.89% 0.98% - 1.35% Expected dividend yield 0% 0% Total expense for stock option grants recognized was as follows: Year Ended December 31, 2022 2021 General and administrative $ 5,111 $ 4,028 Research and development 699 1,340 Total stock-based compensation $ 5,810 $ 5,368 At December 31, 2022, the Company had $5.9 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 1.4 years.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2022
Income Tax Disclosure [Abstract]
Income Taxes	9. Income Taxes No provision for federal income taxes has been recorded for the years ended December 31, 2022 and 2021 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, 2022 2021 Deferred tax assets: Net operating losses $ 151,433 $ 143,732 Research and other credits 2,178 2,178 Stock based compensation 4,087 3,354 In-Process research and development 511 1,132 Capitalized research and development costs 12,686 - Other 468 230 Total deferred tax assets 171,363 150,626 Valuation allowance (171,363 ) (150,626 ) Net deferred tax assets $ - $ - A reconciliation of the statutory tax rates to the effective tax rates for the years ended December 2022 and 2021 is as follows: Year Ended December 31, 2022 2021 Statutory rate 21.0 % 21.0 % Valuation allowance (29.8 )% (28.5 )% Nondeductible stock compensation 1.9 % 0.4 % Other 6.9 % 7.1 % Effective tax rate - % - % 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 $20.7 million and $68.2 million during the years ended December 31, 2022 and 2021, respectively. At December 31, 2022, the Company had federal net operating loss carryforwards of approximately $166.2 million, which expire in the years 2024 through 2037, and state net operating loss carryforwards of approximately $542.9 million, which expire in the years 2028 through 2042. The Company also has federal net operating loss carryforwards generated in the years 2018 through 2022 of $375.3 million that have no expiration date. At December 31, 2022, the Company had federal research and development credit carryforwards of approximately $1.3 million, which expire in the years 2022 through 2035 and state research and development credit carryforwards of approximately $2.2 million. The state research and development credit carryforwards can be carried forward indefinitely. 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 in periods subsequent to the completion of the Section 382 study. As a result, tax attributes such as net operating losses and research and development credits may be subject to further limitation. 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, 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 Additions based on tax positions related to prior year - Additions based on tax positions related to current year - Balance at December 31, 2022 $ 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. The Company files income tax returns in the US federal jurisdiction, California and Florida. Federal and Florida corporate income tax returns beginning with 2019 remain subject to examination by the Internal Revenue Service and Florida Department of Revenue, respectively. California corporation income tax returns beginning with the 2018 tax year remain subject to examination the California Franchise Tax Board.

Employee Benefit Plan

Employee Benefit Plan	12 Months Ended
	Dec. 31, 2022
Employee Benefit Plan [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 $24 thousand and $23 thousand in matching contributions to the 401(k) Plan for the years ended December 31, 2022 and 2021, respectively.

Litigation

Litigation	12 Months Ended
	Dec. 31, 2022
Litigation Settlement [Abstract]
Litigation	11. Litigation Eversana Arbitration On May 19, 2022, Eversana filed a Demand for Arbitration claiming approximately $4.5 million in damages against the Company with the American Arbitration Association entitled Eversana Life Sciences, LLC v. Humanigen, Inc. Avid Settlement On February 21, 2023, the Company and Avid Bioservices, Inc. (“Avid”) entered into a Settlement Agreement (the “Settlement Agreement”) providing for a conditional resolution of certain previously reported disputes between the Company and Avid arising pursuant to the commercial agreements between the two parties (collectively, the “Lenzilumab Disputes”). Pursuant to the Settlement Agreement, the Company made a one-time payment of $3.0 million to Avid (the “Settlement Payment”). In addition, the parties mutually agreed that, effective upon the expiration of 120 days from the date of the Settlement Agreement and only if Humanigen has not by such date filed for or been placed into bankruptcy or commenced an assignment for the benefit of creditors or other insolvency proceeding, the parties will dismiss the pending Lenzilumab Disputes and release and discharge each other from all existing claims, demands, causes of actions, charges and grievances of any kind arising out of, or relating to, the Lenzilumab Disputes and the commercial agreements between the parties, which were terminated in accordance with their respective terms. Catalent Settlement On December 16, 2022, the Company and Catalent entered into a Settlement Agreement (the “Settlement Agreement”) resolving certain previously reported disputes between the Company and Catalent that had arisen under the Multiple Facility Clinical Supply and Services Agreement (the “MSA”) dated July 31, 2020, by and between Catalent and the Company, pursuant to which Catalent had agreed to perform certain services relating to the manufacturing of lenzilumab, the Company’s lead product candidate. Pursuant to the Settlement Agreement, the Company agreed to make a one-time payment of $12 million (the “Settlement Payment”) to Catalent in full satisfaction of all of the Company’s payment obligations under the MSA for products and prior services, as well as cancellation fees Catalent claimed to be owed. In consideration of its receipt of the Settlement Payment, which the Company made on December 22, 2022, Catalent waived and released Catalent’s rights to pursue all payments, claims, or invoices for such products and services and cancellation fees, as well as for some limited additional work to be performed by Catalent, quantified at approximately $23.5 million in the aggregate. The terms and conditions of the MSA generally will remain in full force and effect with respect to any ongoing activities and additional work to be performed by Catalent. Savant Litigation The Company was previously involved in litigation against Savant Neglected Diseases, LLC (“Savant”). In March 2022, the Company and Savant reached a confidential settlement. Accordingly, the litigation involving Savant was dismissed on March 31, 2022. Thermo Litigation Thermo has notified the Company that they have stopped production and have issued a demand for payment for unreleased batches of product. There is significant drug product that was in production at Thermo for which material has not yet been released by the Company because the batches produced are out of specification. On October 24, 2022, Thermo filed a lawsuit against the Company in Delaware Superior Court ( Patheon Biologics, Inc. v. Humanigen, Inc., Securities Class Action Litigation On August 26, 2022, a putative securities class action complaint captioned Pieroni v. Humanigen Inc., et al., Greenbaum v. Humanigen Inc., et al. Shareholder Derivative Litigation On January 19, 2023, a derivative lawsuit captioned Chul Yang derivatively on behalf of Humanigen, Inc. v. Durrant, et al.

License and Collaboration Agree

License and Collaboration Agreements	12 Months Ended
	Dec. 31, 2022
Research and Development [Abstract]
License and Collaboration Agreements	12. License and Collaboration Agreements 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 US 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 was evaluated in the NIAID-sponsored 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, in hospitalized patients with COVID-19. In July 2022, topline results from the ACTIV-5/BET-B trial were released. Based on the topline results, the trial did not achieve statistical significance on the primary endpoint, although the topline results did indicate that lenzilumab demonstrated a positive trend in mortality. A global group of leading institutions and research networks has indicated interest in including lenzilumab in their large-scale, multinational studies of COVID-19, pending an uptick in ICU admissions.

Subsequent Events

Subsequent Events	12 Months Ended
	Dec. 31, 2022
Subsequent Events [Abstract]
Subsequent Events	13. Subsequent Events The Company has executed a non-binding letter of intent and is engaged in exclusive negotiations relating to a proposed business combination with a privately held biopharmaceutical company (the “Partner Company”). The proposed terms for the business combination contemplate a tax-free stock-for-stock merger, as a result of which Humanigen would issue shares of its capital stock to stockholders of the Partner Company which are expected to represent roughly two times the number of Humanigen’s currently outstanding shares of common stock. The Company cannot assure you that Humanigen and the Partner Company will enter into a definitive agreement for the proposed transaction, and the final form and terms of any such transaction may be materially different from the terms described above. The Company’s ability to enter into a definitive agreement is subject to conditions, including that the Company has received binding commitments for investment of additional capital that will be necessary to fund the operations of the combined company going forward and enable the combined company to maintain a listing of its common stock on the Nasdaq Capital Market or another national securities exchange, as well as customary matters such as approval of the terms of the definitive agreement by the Partner Company’s board of directors and stockholders. Certain of these conditions will be out of the Company’s control. Accordingly, the Company cannot provide any assurance that it will effect the proposed business combination and related financing transactions. If the Company is unable to complete the proposed transactions or identify and complete another strategic or financing transaction in the first half of 2023, the Company may elect or be required to pursue a reorganization or seek other protection under the federal bankruptcy code. See “Risk Factors” beginning on page 22 of this Form 10-K for further discussion of the risks surrounding the proposed transaction and the Company.

Accounting Policies, by Policy

Accounting Policies, by Policy (Policies)	12 Months Ended
	Dec. 31, 2022
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 US generally accepted accounting principles (“US 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 US 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 $2.5 million and $3.6 million in revenue for the years ended December 31, 2022 and 2021, 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. 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. 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 potentially 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, 2022 2021 Options to purchase common stock 7,472,056 4,429,906 Warrants to purchase common stock 31,238 31,238 Convertible debt - 510,986 7,503,294 4,972,130
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 Recent accounting pronouncements issued by the Financial Accounting Standards Board (“FASB”), including its Emerging Issues Task Force, the American Institute of Certified Public Accountants, and the Securities and Exchange Commission (the “SEC”) did not or are not believed by management to have a material impact on the Company's present or future financial statements.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2022
Accounting Policies [Abstract]
Schedule of diluted net loss per common share	As of December 31, 2022 2021 Options to purchase common stock 7,472,056 4,429,906 Warrants to purchase common stock 31,238 31,238 Convertible debt - 510,986 7,503,294 4,972,130

License Revenue (Tables)

License Revenue (Tables)	12 Months Ended
	Dec. 31, 2022
License Revenue [Abstract]
Schedule of contract liability	Balance at January 1, 2021 $ 4,216 Additions (1) 4,542 Deductions for performance obligations satisfied: In current period (1,721 ) In prior period (1,874 ) Balance at December 31, 2021 5,163 Deductions for performance obligations satisfied: In current period (2,514 ) Balance at December 31, 2022 $ 2,649 (1)

Accrued Expenses (Tables)

Accrued Expenses (Tables)	12 Months Ended
	Dec. 31, 2022
Accrued Expenses [Abstract]
Schedule of accrued expenses	As of December 31, 2022 2021 Accrued contract manufacturing-related $ 13,325 $ 16,174 Accrued milestone and royalties 736 2,736 Accrued clinical trial-related 205 160 Accrued compensation-related 106 44 Accrued other 419 768 $ 14,791 $ 19,882

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2022
Income Tax Disclosure [Abstract]
Schedule of deferred tax assets	As of December 31, 2022 2021 Deferred tax assets: Net operating losses $ 151,433 $ 143,732 Research and other credits 2,178 2,178 Stock based compensation 4,087 3,354 In-Process research and development 511 1,132 Capitalized research and development costs 12,686 - Other 468 230 Total deferred tax assets 171,363 150,626 Valuation allowance (171,363 ) (150,626 ) Net deferred tax assets $ - $ -
Schedule of statutory tax rates and the effective tax rates	Year Ended December 31, 2022 2021 Statutory rate 21.0 % 21.0 % Valuation allowance (29.8 )% (28.5 )% Nondeductible stock compensation 1.9 % 0.4 % Other 6.9 % 7.1 % Effective tax rate - % - %
Schedule of unrecognized tax benefits	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 Additions based on tax positions related to prior year - Additions based on tax positions related to current year - Balance at December 31, 2022 $ 1,060

Organization and Description _2

Organization and Description of Business (Details) $ in Millions	Dec. 31, 2022 USD ($)
Nature of Operations [Abstract]
Cash and cash equivalents	$ 10.2
Accounts payable and accrued expenses	55.3
Remaining commitments	$ 2.6

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
South Korea agreement [Member]
Summary of Significant Accounting Policies (Details) [Line Items]
Revenue	$ 2.5	$ 3.6

Summary of Significant Accoun_4

Summary of Significant Accounting Policies (Details) - Schedule of diluted net loss per common share - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Schedule Of Diluted Net Loss Per Common Share [Abstract]
Options to purchase common stock	$ 7,472,056	$ 4,429,906
Warrants to purchase common stock	31,238	31,238
Convertible debt		510,986
Total	$ 7,503,294	$ 4,972,130

License Revenue (Details)

License Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Sep. 30, 2022
License Revenue (Details) [Line Items]
Upfront license Payment			$ 6,000		$ 6,000
Net of withholding taxes and other fees and royalties	$ 4,500				$ 4,500
Milestone license payments		$ 14,000
Licensee term			7 years 6 months
Upfront payment			$ 4,500
Deferred revenue						$ 800
License revenue			2,500	$ 3,600
Deferred revenue, current			883	$ 4,145
First Milestone [Member]
License Revenue (Details) [Line Items]
Milestone license payments	$ 6,000
South Korea agreement [Member]
License Revenue (Details) [Line Items]
Deferred revenue			$ 2,600

License Revenue (Details) - Sch

License Revenue (Details) - Schedule of contract liability - South Korea agreement [Member] - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2022	Dec. 31, 2021
License Revenue (Details) - Schedule of contract liability [Line Items]
Balance at Beginning		$ 5,163	$ 4,216
Additions	[1]		4,542
Deductions for performance obligations satisfied:
In current period		(2,514)	(1,721)
In prior period			(1,874)
Balance at Ending		$ 2,649	$ 5,163
[1](1) Milestone payment of $6.0 million (or $4.5 million net of withholding taxes and other fees and royalties).

Accrued Expenses (Details) - Sc

Accrued Expenses (Details) - Schedule of accrued expenses - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Accrued Liabilities, Current [Abstract]
Accrued contract manufacturing-related	$ 13,325	$ 16,174
Accrued milestone and royalties	736	2,736
Accrued clinical trial-related	205	160
Accrued compensation-related	106	44
Accrued other	419	768
Total accrued expenses	$ 14,791	$ 19,882

Debt (Details)

Debt (Details) - USD ($) $ in Millions	1 Months Ended	12 Months Ended
	Jul. 31, 2022	Dec. 31, 2022	Dec. 31, 2021	Mar. 29, 2021	Mar. 10, 2021
Debt (Details) [Line Items]
Accrued interest percentage		8.75%
Interest expense		$ 1.2
Secured Term Loan Facility [Member]
Debt (Details) [Line Items]
Principal amount					$ 80
Draw amount				$ 25
Net proceeds		$ 24.4
Prime rate, percentage		8.75%
Floating interest rate, deduction		3.25%
Repayment of term loan	$ 25
Accrued interest	$ 1.7
Interest expense		$ 2.9	$ 2.3
Effective interest rate		9.30%	9%

Warrants to Purchase Common S_2

Warrants to Purchase Common Stock (Details) - $ / shares		1 Months Ended
	Jun. 30, 2020	Jun. 30, 2021	May 20, 2020	Jun. 30, 2016	Jun. 19, 2013	Dec. 31, 2022	Jul. 30, 2020
Warrants to Purchase Common Stock (Details) [Line Items]
Warrant aggregate share			30,000		1,238
Exercise price (in Dollars per share)					$ 484.8
Exercise shares issued							10,909
Exercise price (in Dollars per share)			$ 4.3	$ 11.25
Warrant exercisable percentage				25%
Gross warrants exercised	20,000	20,000
Expire term						10 years
Common Stock [Member]
Warrants to Purchase Common Stock (Details) [Line Items]
Exercise shares issued				40,000

Commitments and Contingencies (

Commitments and Contingencies (Details) - USD ($)	1 Months Ended		6 Months Ended	12 Months Ended
	Oct. 24, 2022	May 19, 2022	Sep. 30, 2021	Dec. 31, 2022	Dec. 31, 2021	Sep. 30, 2022	Sep. 01, 2022	Feb. 03, 2022
Commitments and Contingencies (Details) [Line Items]
Payment requested for services rendered	$ 25,900,000
Manufacturing commitments				$ 2,600,000
Countersuit amount				$ 37,500,000
Rent expense						$ 1,200	$ 1,200	$ 300
Expire date				Aug. 31, 2023
Lease cost				$ 20,000	$ 14,000
Future minimum lease payments				15,000
2022 [Member]
Commitments and Contingencies (Details) [Line Items]
Manufacturing commitments				2,600,000
Thermo litigation [Member]
Commitments and Contingencies (Details) [Line Items]
Payment requested for services rendered				$ 25,900,000
Eversana Agreement [Member]
Commitments and Contingencies (Details) [Line Items]
Payment requested for services rendered		$ 4,500,000	$ 4,500,000

Stockholders_ Equity (Details)

Stockholders’ Equity (Details) - USD ($) $ / shares in Units, $ in Millions		1 Months Ended	12 Months Ended
	May 03, 2021	Mar. 30, 2021	Dec. 31, 2022	Dec. 31, 2021	Apr. 14, 2022	Dec. 31, 2020	Jul. 29, 2020
Stockholders’ Equity (Details) [Line Items]
Additional shares purchased	$ 100.4
Shares of common stock (in Shares)				6,408,087
Net proceeds				$ 65.7
Shares of common stock reserved (in Shares)			9,451,429
expiration period			10 years
Fair value of options vested			$ 0.7	$ 2.3
Stock options granted (in Dollars per share)			$ 0.47	$ 10.32
Total unrecognized compensation expense			$ 5.9
Weighted-average period			5 years 7 months 6 days
2020 Equity Plan [Member]
Stockholders’ Equity (Details) [Line Items]
Percentage of stockholders							63%
Shares of common stock reserved (in Shares)			7,000,000
Available shares for grant (in Shares)			1,948,135
Stock option grants [Member]
Stockholders’ Equity (Details) [Line Items]
Weighted-average period			1 year 4 months 24 days
Underwritten Public Offering 2021 [Member]
Stockholders’ Equity (Details) [Line Items]
Sale of additional shares of common stock (in Shares)	427,017
Aggregate gross proceeds from sale of shares (in Shares)	5,427,017
Proceeds from sale of shares after offering costs	$ 94.2
Jefferies LLC [Member] | Underwriting Agreement [Member]
Stockholders’ Equity (Details) [Line Items]
Shares issued in public offering (in Shares)		5,000,000
Shares of common stock (in Shares)		750,000
Cantor Fitzgerald And Co [Member] | Controlled equity offering sm sales agreement [Member]
Stockholders’ Equity (Details) [Line Items]
Maximum aggregate gross offering price						$ 100
Additional maximum aggregate gross offering price					$ 75
Shares of common stock (in Shares)			55,052,506
Net proceeds			$ 41.8

Stockholders_ Equity (Details)

Stockholders’ Equity (Details) - Schedule of shares of common stock reserved for issuance	12 Months Ended
	Dec. 31, 2022 shares
Stockholders’ Equity (Details) - Schedule of shares of common stock reserved for issuance [Line Items]
Warrants to purchase common stock	31,238
Options:
Total common stock reserved for future issuance	9,451,429
2020 Equity Incentive Plan [Member]
Options:
Outstanding under the 2012 Equity Incentive Plan	5,018,389
Available for future grants under the 2020 Equity Incentive Plan	1,948,135
2012 Equity Incentive Plan [Member]
Options:
Outstanding under the 2012 Equity Incentive Plan	2,453,667

Stockholders_ Equity (Details_2

Stockholders’ Equity (Details) - Schedule of stock option activity - USD ($)		12 Months Ended
		Dec. 31, 2022	Dec. 31, 2021
Schedule Of Stock Option Activity Abstract
Outstanding Beginning Balance, Number of Shares (in Shares)		4,429,906	3,732,149
Outstanding Beginning Balance, Weighted Average Exercise Price	[1]	$ 7.89	$ 5.57
Outstanding Ending Balance, Number of Shares (in Shares)		7,472,056	4,429,906
Outstanding Ending Balance, Weighted Average Exercise Price	[1]	$ 4.23	$ 7.89
Outstanding Ending Balance, Weighted-Average Remaining Contractual Term		7 years 7 months 6 days
Outstanding Ending Balance, Aggregate Intrinsic Value (in Dollars)	[2]
Number of Shares, Options vested and expected to vest (in Shares)		7,237,665
Weighted Average Exercise Price, Options vested and expected to vest	[1]	$ 4.32
Weighted-Average Remaining Contractual Term, Options vested and expected to vest		7 years 7 months 6 days
Aggregate Intrinsic Value, Options vested and expected to vest (in Dollars)	[2]
Number of Shares, Exercisable (in Shares)		3,435,577
Weighted Average Exercise Price, Exercisable	[1]	$ 6.7
Weighted-Average Remaining Contractual Term, Exercisable		5 years 7 months 6 days
Aggregate Intrinsic Value, Exercisable (in Dollars)	[2]
Number of Shares, Granted (in Shares)		4,708,969	1,444,176
Weighted Average Exercise Price, Granted	[1]	$ 0.57	$ 12.58
Number of Shares, Exercised (in Shares)			(582,936)
Weighted Average Exercise Price, Exercised	[1]		$ 3.98
Number of Shares, Cancelled (forfeited) (in Shares)		(1,568,912)	(81,711)
Weighted Average Exercise Price, Cancelled (forfeited)	[1]	$ 2.94	$ 7.09
Number of Shares, Cancelled (expired)		(97,907)	(81,772)
Weighted Average Exercise Price, Cancelled (forfeited)	[1]	$ 14.45	$ 13.71
[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, 2022.

Stockholders_ Equity (Details_3

Stockholders’ Equity (Details) - Schedule of stock options outstanding and exercisable by exercise price	12 Months Ended
	Dec. 31, 2022 $ / shares shares
Share-Based Payment Arrangement, Option, Exercise Price Range [Line Items]
Stock Options Outstanding, Number of Shares | shares	7,472,056
Stock Options Outstanding, Weighted - Average Remaining Contractual Life In Years	7 years 7 months 6 days
Stock Options Outstanding, Weighted - Average Exercise Price Per Share | $ / shares	$ 4.23
Stock Options Exercisable, Number of Shares | shares	3,435,577
Stock Options Exercisable, Weighted - Average Exercise Price Per Share | $ / shares	$ 6.7
Exercise Price Range From $0.38 - $0.38 [Member]
Share-Based Payment Arrangement, Option, Exercise Price Range [Line Items]
Stock Options Outstanding, Number of Shares | shares	3,221,367
Stock Options Outstanding, Weighted - Average Remaining Contractual Life In Years	9 years 7 months 6 days
Stock Options Outstanding, Weighted - Average Exercise Price Per Share | $ / shares	$ 0.38
Stock Options Exercisable, Number of Shares | shares	0
Stock Options Exercisable, Weighted - Average Exercise Price Per Share | $ / shares
Exercise Price Range from $1.90 - $2.99 [Member]
Share-Based Payment Arrangement, Option, Exercise Price Range [Line Items]
Stock Options Outstanding, Number of Shares | shares	455,915
Stock Options Outstanding, Weighted - Average Remaining Contractual Life In Years	8 years 1 month 6 days
Stock Options Outstanding, Weighted - Average Exercise Price Per Share | $ / shares	$ 2.6
Stock Options Exercisable, Number of Shares | shares	216,795
Stock Options Exercisable, Weighted - Average Exercise Price Per Share | $ / shares	$ 2.16
Exercise Price Range $3.33 - $3.33 [Member]
Share-Based Payment Arrangement, Option, Exercise Price Range [Line Items]
Stock Options Outstanding, Number of Shares | shares	1,894,168
Stock Options Outstanding, Weighted - Average Remaining Contractual Life In Years	4 years 9 months 18 days
Stock Options Outstanding, Weighted - Average Exercise Price Per Share | $ / shares	$ 3.33
Stock Options Exercisable, Number of Shares | shares	1,894,168
Stock Options Exercisable, Weighted - Average Exercise Price Per Share | $ / shares	$ 3.33
Exercise Price Range From $3.5 - $16.07 [Member]
Share-Based Payment Arrangement, Option, Exercise Price Range [Line Items]
Stock Options Outstanding, Number of Shares | shares	1,607,002
Stock Options Outstanding, Weighted - Average Remaining Contractual Life In Years	7 years 7 months 6 days
Stock Options Outstanding, Weighted - Average Exercise Price Per Share | $ / shares	$ 11.12
Stock Options Exercisable, Number of Shares | shares	1,051,427
Stock Options Exercisable, Weighted - Average Exercise Price Per Share | $ / shares	$ 11.02
Exercise Price Range From $16.90 - $16.90 [Member]
Share-Based Payment Arrangement, Option, Exercise Price Range [Line Items]
Stock Options Outstanding, Number of Shares | shares	248,604
Stock Options Outstanding, Weighted - Average Remaining Contractual Life In Years	3 years 4 months 24 days
Stock Options Outstanding, Weighted - Average Exercise Price Per Share | $ / shares	$ 16.9
Stock Options Exercisable, Number of Shares | shares	248,604
Stock Options Exercisable, Weighted - Average Exercise Price Per Share | $ / shares	$ 16.9
Exercise Price Range From $17.79 - $17.79 [Member]
Share-Based Payment Arrangement, Option, Exercise Price Range [Line Items]
Stock Options Outstanding, Number of Shares | shares	25,000
Stock Options Outstanding, Weighted - Average Remaining Contractual Life In Years	8 years 2 months 12 days
Stock Options Outstanding, Weighted - Average Exercise Price Per Share | $ / shares	$ 17.79
Stock Options Exercisable, Number of Shares | shares	14,583
Stock Options Exercisable, Weighted - Average Exercise Price Per Share | $ / shares	$ 17.79
Exercise Price Range From $20.00 - $20.00 [Member]
Share-Based Payment Arrangement, Option, Exercise Price Range [Line Items]
Stock Options Outstanding, Number of Shares | shares	20,000
Stock Options Outstanding, Weighted - Average Remaining Contractual Life In Years	8 years 4 months 24 days
Stock Options Outstanding, Weighted - Average Exercise Price Per Share | $ / shares	$ 20
Stock Options Exercisable, Number of Shares | shares	10,000
Stock Options Exercisable, Weighted - Average Exercise Price Per Share | $ / shares	$ 20

Stockholders_ Equity (Details_4

Stockholders’ Equity (Details) - Schedule of date of grant using the Black-Scholes model	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Stockholders’ Equity (Details) - Schedule of date of grant using the Black-Scholes model [Line Items]
Expected term	6 years
Expected dividend yield	0%	0%
Minimum [Member]
Stockholders’ Equity (Details) - Schedule of date of grant using the Black-Scholes model [Line Items]
Expected term		5 years
Expected volatility	104%	104%
Risk-free interest rate	1.59%	0.98%
Maximum [Member]
Stockholders’ Equity (Details) - Schedule of date of grant using the Black-Scholes model [Line Items]
Expected term		6 years
Expected volatility	109%	109%
Risk-free interest rate	2.89%	1.35%

Stockholders_ Equity (Details_5

Stockholders’ Equity (Details) - Schedule of total expense for stock option grants recognized - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Stockholders’ Equity (Details) - Schedule of total expense for stock option grants recognized [Line Items]
Total stock-based compensation	$ 5,810	$ 5,368
General and Administrative Expense [Member]
Stockholders’ Equity (Details) - Schedule of total expense for stock option grants recognized [Line Items]
Total stock-based compensation	5,111	4,028
Research and Development Expense [Member]
Stockholders’ Equity (Details) - Schedule of total expense for stock option grants recognized [Line Items]
Total stock-based compensation	$ 699	$ 1,340

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2018
Income Taxes (Details) [Line Items]
Valuation allowance increased	$ 20.7	$ 68.2
Federal [Member]
Income Taxes (Details) [Line Items]
Net operating loss carryforwards	$ 166.2		$ 375.3
Federal [Member] | Minimum [Member]
Income Taxes (Details) [Line Items]
Expire year	2024
Federal [Member] | Maximum [Member]
Income Taxes (Details) [Line Items]
Expire year	2037
Federal [Member] | Research and Development [Member]
Income Taxes (Details) [Line Items]
Credit carryforwards	$ 1.3
Federal [Member] | Research and Development [Member] | Minimum [Member]
Income Taxes (Details) [Line Items]
Expire year	2022
Federal [Member] | Research and Development [Member] | Maximum [Member]
Income Taxes (Details) [Line Items]
Expire year	2035
State [Member]
Income Taxes (Details) [Line Items]
Net operating loss carryforwards	$ 542.9
State [Member] | Minimum [Member]
Income Taxes (Details) [Line Items]
Expire year	2028
State [Member] | Maximum [Member]
Income Taxes (Details) [Line Items]
Expire year	2042
State [Member] | Research and Development [Member]
Income Taxes (Details) [Line Items]
Credit carryforwards	$ 2.2

Income Taxes (Details) - Schedu

Income Taxes (Details) - Schedule of deferred tax assets - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Deferred tax assets:
Net operating losses	$ 151,433	$ 143,732
Research and other credits	2,178	2,178
Stock based compensation	4,087	3,354
In-Process research and development	511	1,132
Capitalized research and development costs	12,686
Other	468	230
Total deferred tax assets	171,363	150,626
Valuation allowance	(171,363)	(150,626)
Net deferred tax assets

Income Taxes (Details) - Sche_2

Income Taxes (Details) - Schedule of statutory tax rates and the effective tax rates	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Schedule Of Statutory Tax Rates And The Effective Tax Rates Abstract
Statutory rate	21%	21%
Valuation allowance	(29.80%)	(28.50%)
Nondeductible stock compensation	1.90%	0.40%
Other	6.90%	7.10%
Effective tax rate

Income Taxes (Details) - Sche_3

Income Taxes (Details) - Schedule of unrecognized tax benefits - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Schedule Of Unrecognized Tax Benefits Abstract
Balance at	$ 1,060	$ 1,060
Additions based on tax positions related to prior year
Additions based on tax positions related to current year
Balance at	$ 1,060	$ 1,060

Employee Benefit Plan (Details)

Employee Benefit Plan (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Employee Benefit Plan [Abstract]
Employer contributions	$ 24	$ 23

Litigation (Details)

Litigation (Details) - USD ($) $ in Millions	1 Months Ended		6 Months Ended	12 Months Ended
	Oct. 24, 2022	May 19, 2022	Sep. 30, 2021	Dec. 31, 2022
Litigation (Details) [Line Items]
Loss Contingency Damages Sought Value	$ 25.9
Paid to catalent				$ 12
Aggregate of products, services and cancellation fees				23.5
Countersuit amount				37.5
Avid Arbitration [Member]
Litigation (Details) [Line Items]
Countersuit amount				37.5
Eversana Agreement [Member]
Litigation (Details) [Line Items]
Loss Contingency Damages Sought Value		$ 4.5	$ 4.5
Settlement Agreement [Member]
Litigation (Details) [Line Items]
Paid to avid				$ 3

License and Collaboration Agr_2

License and Collaboration Agreements (Details) $ in Millions	1 Months Ended
	Jun. 30, 2020 USD ($)
Research and Development [Abstract]
Amount paid in license agreement	$ 0.2