Bellicum Pharmaceuticals (BLCM) 10-Q 12 May 22 2022 Q1 Quarterly report Financial data

Cover Page

Cover Page - shares	3 Months Ended
	Mar. 31, 2022	May 09, 2022
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2022
Document Transition Report	false
Entity File Number	001-36783
Entity Registrant Name	BELLICUM PHARMACEUTICALS, INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	20-1450200
Entity Address, Address Line One	3730 Kirby Drive,
Entity Address, Address Line Two	Suite 1200,
Entity Address, City or Town	Houston,
Entity Address, State or Province	TX
Entity Address, Postal Zip Code	77098
City Area Code	281
Local Phone Number	454-3424
Title of 12(b) Security	Common Stock, par value $0.01 per share
Trading Symbol	BLCM
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding (in shares)		8,609,661
Entity Central Index Key	0001358403
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	Q1
Amendment Flag	false

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Current assets:
Cash and cash equivalents	$ 39,769	$ 46,156
Restricted cash	1,501	1,501
Accounts receivable, interest and other receivables	207	205
Prepaid expenses and other current assets	1,943	1,269
Total current assets	43,420	49,131
Property and equipment, net	14	12
Total assets	43,434	49,143
Current liabilities:
Accounts payable	212	90
Accrued expenses and other current liabilities	3,347	3,849
Warrant derivative liability	4,410	2,773
Total liabilities	7,969	6,712
Commitments and contingencies
Redeemable preferred stock: $0.01 par value; 10,000,000 shares authorized Series 1 redeemable convertible preferred stock, $0.01 par value, 1,517,500 shares authorized at March 31, 2022 and December 31, 2021, 452,000 shares issued and outstanding at March 31, 2022 and December 31, 2021	18,036	18,036
Stockholders’ equity:
Common stock, $0.01 par value; 80,000,000 shares authorized at March 31, 2022 and December 31, 2021, 8,676,903 shares issued and 8,609,157 shares outstanding at March 31, 2022; 8,497,025 shares issued and 8,429,279 shares outstanding at December 31, 2021	87	85
Treasury stock: 67,746 shares held at March 31, 2022 and December 31, 2021	(5,056)	(5,056)
Additional paid-in capital	580,753	580,156
Accumulated other comprehensive loss	(341)	(338)
Accumulated deficit	(558,014)	(550,452)
Total stockholders’ equity	17,429	24,395
Total liabilities, redeemable preferred stock and stockholders' equity	$ 43,434	$ 49,143

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Mar. 31, 2022	Dec. 31, 2021
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, authorized (in shares)	10,000,000	10,000,000
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, authorized (in shares)	80,000,000	80,000,000
Common stock, issued (in shares)	8,676,903	8,497,025
Common stock, outstanding (in shares)	8,609,157	8,429,279
Treasury stock, shares (in shares)	67,746	67,746
Convertible Preferred Stock
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, authorized (in shares)	1,517,500	1,517,500
Preferred stock, shares issued (in shares)	452,000	452,000
Preferred stock, outstanding (in shares)	452,000	452,000

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Operating expenses
Research and development	$ 4,486	$ 6,460
General and administrative	1,453	2,012
Total operating expenses	5,939	8,472
Other operating expense
Loss on dispositions, net	0	464
Loss from operations	(5,939)	(8,936)
Other income (expense):
Interest income	14	10
Interest expense	0	(4)
Change in fair value of warrant derivative and private placement option liabilities	(1,637)	(2,337)
Total other expense	(1,623)	(2,331)
Net loss	$ (7,562)	$ (11,267)
Net loss per common share attributable to common shareholders, basic (in dollars per share)	$ (0.25)	$ (1.12)
Net loss per common share attributable to common shareholders, diluted (in dollars per share)	$ (0.25)	$ (1.12)
Weighted-average shares outstanding, basic (in shares)	30,819,578	10,034,970
Weighted-average shares outstanding, diluted (in shares)	30,819,578	10,034,970
Net loss	$ (7,562)	$ (11,267)
Other comprehensive loss:
Foreign currency translation adjustment	(3)	0
Comprehensive loss	$ (7,565)	$ (11,267)

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Redeemable Convertible Preferred Stock and Stockholders’ Equity (Deficit) - USD ($) $ in Thousands	Total	Common Stock	Treasury Stock	Additional Paid-In Capital	Accumulated Deficit	Accumulated Other Comprehensive Loss	Series 1 Preferred
Preferred stock, beginning balance (in shares) at Dec. 31, 2020							452,000
Preferred stock, beginning balance at Dec. 31, 2020							$ 18,036
Preferred stock, ending balance (in shares) at Mar. 31, 2021							452,000
Preferred stock, ending balance at Mar. 31, 2021							$ 18,036
Balance, beginning of period (in shares) at Dec. 31, 2020		8,385,650	67,746
Balance, beginning of period at Dec. 31, 2020	$ (2,497)	$ 84	$ (5,056)	$ 543,561	$ (540,747)	$ (339)
Increase (Decrease) in Stockholders' Equity
Share-based compensation	903			903
Exercise of restricted stock unit awards (in shares)		369
Comprehensive loss	(11,267)				(11,267)	0
Balance, end of period (in shares) at Mar. 31, 2021		8,386,019	67,746
Balance, end of period at Mar. 31, 2021	(12,861)	$ 84	$ (5,056)	544,464	(552,014)	(339)
Preferred stock, beginning balance (in shares) at Dec. 31, 2021							452,000
Preferred stock, beginning balance at Dec. 31, 2021	18,036						$ 18,036
Preferred stock, ending balance (in shares) at Mar. 31, 2022							452,000
Preferred stock, ending balance at Mar. 31, 2022	18,036						$ 18,036
Balance, beginning of period (in shares) at Dec. 31, 2021		8,497,025	67,746
Balance, beginning of period at Dec. 31, 2021	24,395	$ 85	$ (5,056)	580,156	(550,452)	(338)
Increase (Decrease) in Stockholders' Equity
Share-based compensation	599			599
Issuance of common stock upon vesting of restricted stock units (in shares)		122,928
Issuance of common stock upon vesting of restricted stock units	0	$ 1		(1)
Issuance of common stock upon exercise of pre-funded warrants (in shares)		56,950
Issuance of common stock upon exercise of pre-funded warrants	0	$ 1		(1)
Comprehensive loss	(7,565)				(7,562)	(3)
Balance, end of period (in shares) at Mar. 31, 2022		8,676,903	67,746
Balance, end of period at Mar. 31, 2022	$ 17,429	$ 87	$ (5,056)	$ 580,753	$ (558,014)	$ (341)

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Cash flows from operating activities:
Net loss	$ (7,562)	$ (11,267)
Adjustments to reconcile net loss to net cash used in operating activities:
Share-based compensation	599	903
Depreciation and amortization expense	5	47
Change in fair value of warrant derivative and private placement option liabilities	1,637	2,337
Amortization of right-of-use assets	0	33
Accretion of lease liability	0	31
Loss on dispositions, net	0	464
Changes in operating assets and liabilities:
Accounts receivable, interest and other receivables	(2)	0
Prepaid expenses and other assets	(674)	(679)
Accounts payable	122	(222)
Accrued liabilities and other	(502)	60
Net cash used in operating activities	(6,377)	(8,293)
Cash flows from investing activities:
Proceeds from sale of property and equipment	0	900
Purchases of property and equipment	(7)	0
Net cash (used in) provided by investing activities	(7)	900
Cash flows from financing activities:
Payment on financing lease obligations	0	(20)
Net cash used in financing activities	0	(20)
Effect of exchange rate changes on cash	(3)	0
Net change in cash, cash equivalents, and restricted cash	(6,387)	(7,413)
Cash, cash equivalents and restricted cash at beginning of period	47,657	36,996
Cash, cash equivalents and restricted cash at end of period	$ 41,270	$ 29,583

ORGANIZATION, BASIS OF PRESENTA

ORGANIZATION, BASIS OF PRESENTATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	3 Months Ended
	Mar. 31, 2022
Organization, Consolidation and Presentation of Financial Statements [Abstract]
ORGANIZATION, BASIS OF PRESENTATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	ORGANIZATION, BASIS OF PRESENTATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Organization Bellicum Pharmaceuticals, Inc. (“Bellicum”) is a clinical stage biopharmaceutical company focused on discovering and developing novel cellular immunotherapies for various forms of cancer. Bellicum is devoting substantially all of its present efforts to developing next-generation CAR-T product candidates in cellular immunotherapy. Bellicum has two wholly-owned subsidiaries, Bellicum Pharma Limited, a private limited company organized under the laws of the United Kingdom, and Bellicum Pharma GmbH, a private limited liability company organized under German law. Both were formed for the purpose of developing product candidates in Europe. Bellicum, Bellicum Pharma Limited and Bellicum Pharma GmbH are collectively referred to herein as the “Company.” All intercompany balances and transactions among the consolidated entities have been eliminated in consolidation. Basis of Presentation The accompanying unaudited condensed financial statements have been prepared in conformity with the authoritative U.S. generally accepted accounting principles (“GAAP”) for interim financial information and pursuant to Form 10-Q and Article 10 of Regulation S-X of the Securities and Exchange Commission (“SEC”). Accordingly, the accompanying unaudited condensed consolidated financial statements do not include all of the information and notes required by GAAP for complete financial statements. The unaudited interim financial statements reflect all adjustments which, in the opinion of management, are necessary for a fair statement of the results for the periods presented. All such adjustments are of a normal and recurring nature. The operating results presented in these unaudited condensed consolidated financial statements are not necessarily indicative of the results that may be expected for any future periods. These unaudited condensed consolidated financial statements should be read in conjunction with the audited consolidated financial statements and the notes thereto in the Company’s Annual Report on Form 10-K (“Annual Report”) for the fiscal year ended December 31, 2021, as filed with the SEC on March 24, 2022. The accompanying interim condensed financial statements have been prepared on a going concern basis, which assumes that the Company will continue to realize its assets and discharge its liabilities in the normal course of business. However, as of March 31, 2022 and December 31, 2021, the Company had an accumulated deficit of $558.0 million and $550.5 million, respectively, and at March 31, 2022, the Company had cash and cash equivalents of approximately $39.8 million and restricted cash of $1.5 million. Based on the Company’s current business plan, management believes that existing cash and cash equivalents, revenues and other cash inflows will be sufficient to fund its operating expenses and capital expenditure requirements through June 2023. However, the Company’s operating plan may change as a result of many factors currently unknown, and the Company may need to seek additional funds sooner than planned. Moreover, it is particularly difficult to estimate with certainty the Company’s future expenses given the dynamic nature of its business, the COVID-19 pandemic and the macro-economic environment generally. Existing cash, cash equivalents are not likely to be sufficient to fund the Company's operations through the third quarter of 2023 as management expects to incur additional losses in the future to conduct research and development and recognizes that the Company will need to raise additional capital to fully implement its business plan. This going concern basis of accounting contemplates the recovery of the Company’s assets and the satisfaction of the Company’s liabilities and commitments in the normal course of business and does not include any adjustments to reflect the possible future effects of the recoverability and classification of recorded asset amounts or amounts and classification of liabilities that might be necessary should the Company be unable to continue as a going concern. The Company has recorded losses from operations since its inception and if the Company does not successfully obtain regulatory approval and commercialize any of its product candidates, the Company will not be able to achieve profitability. The Company is subject to risks common to companies in the biotechnology industry and the future success of the Company is dependent on its ability to successfully complete the development of, and obtain regulatory approval for, its product candidates, manage the growth of the organization, obtain additional financing necessary in order to develop, launch and commercialize its product candidates, and compete successfully with other companies in its industry. The Company believes that its current capital resources, which consist of cash and cash equivalents, are sufficient to fund operations. The Company may be required to raise additional capital to fund future operations through the sale of additional equity, incurrence of additional debt, the entry into licensing or collaboration agreements with partners, grants or other sources of financing. Sufficient funds may not be available to the Company at all or on attractive terms when needed from equity or debt financings. If the Company is unable to obtain additional funding from these or other sources when needed, or to the extent needed, it may be necessary to significantly reduce its controllable and variable expenditures and current rate of spending through reductions in staff and delaying, scaling back, or suspending certain research and development, sales and marketing programs and other operational goals. Use of Estimates The preparation of the interim condensed consolidated financial statements in accordance with GAAP requires management to make certain estimates and judgments that affect the reported amounts of assets, liabilities, and expenses. Actual results could differ from those estimates. Significant Accounting Policies There have been no significant changes to the accounting policies during the three months ended March 31, 2022, as compared to the significant accounting policies described in Note 1 of the “Notes to Consolidated Financial Statements” in the Company’s audited financial statements included in its Annual Report for the fiscal year ended December 31, 2021. Cash, Cash Equivalents and Restricted Cash The Company considers all short-term, highly liquid investments with maturity of three months or less from the date of purchase and that can be liquidated without prior notice or penalty, to be cash equivalents. The following table provides a reconciliation of cash, cash equivalents and restricted cash reported within the balance sheets that sum to the total of the same such amounts shown in the statements of cash flows. (in thousands) March 31, 2022 December 31, 2021 Cash and cash equivalents $ 39,769 $ 46,156 Restricted cash 1,501 1,501 Total cash, cash equivalents and restricted cash shown in the statements of cash flows $ 41,270 $ 47,657 In April 2020, the Company sold its U.S. manufacturing facility to The University of Texas M.D. Anderson Cancer Center (“M.D. Anderson”). Pursuant to the Company’s asset purchase agreement with M.D. Anderson, $1.5 million of the cash proceeds received are subject to certain escrow provisions and recorded as restricted cash. The funds are required to be held until any claims against the escrow are resolved. Disposition of Assets and Liabilities Held for Sale and Held for Use In the fourth quarter of 2020, in connection with the Company's restructuring plan, Management elected to seek an exit to its leased R&D facility in Houston, Texas. The lease termination and disposal of the assets and liabilities associated with the facility was completed on February 26, 2021. Under the terms of the agreement, a third party assumed the lease for the facility. In addition, the third party paid $1.1 million to the Company for substantially all of the property, and equipment associated with the location. The consideration included $0.9 million in cash and an unsecured promissory note for $0.2 million. On March 15, 2021, the Company entered an agreement to terminate its sub-lease of the South San Francisco office space contingent upon consent of the prime lessor. Under the terms of the agreement, the company agreed to pay a lease termination fee of $0.9 million while the security deposit of $0.2 million will be returned to the Company. The decision to exit this lease reflects the ability of the Company to carry on administrative functions remotely. On March 26, 2021, the Company met all of the conditions of the agreement and disposed of substantially all of the assets and liabilities associated with the lease including the a right-of-use asset of $0.6 million, leased equipment with net book value less than $0.1 million, and the related lease liability of $1 million. The Company recognized a loss on termination of $0.5 million during the first quarter of 2021. Accrued Expenses and Other Current Liabilities Accrued expenses and other liabilities consist of the following: (in thousands) March 31, 2022 December 31, 2021 Accrued payroll $ 166 $ 320 Accrued patient treatment costs 1,393 2,086 Accrued clinical research costs 663 479 Accrued manufacturing costs 388 328 Accrued professional services 417 305 Accrued other 320 331 Total accrued expenses and other current liabilities $ 3,347 $ 3,849 Net Loss and Net Loss per Share of Common Stock Attributable to Common Stockholders Basic net loss per share attributable to common stockholders is calculated by dividing the net loss attributable to common stockholders by the weighted-average number of shares of common stock outstanding during the period without consideration for common stock equivalents. Diluted earnings per share is based on the more dilutive method between the two-class method and the treasury stock method and includes the effect from potential issuance of ordinary shares, such as shares issuable pursuant to the conversion of preferred stock to common stock, exercise of warrants to purchase common stock, exercise of stock options, and vesting of restricted stock units. For periods of net loss, diluted net loss per share is calculated similarly to basic net loss per share. For warrants that are recorded as a liability in the accompanying condensed consolidated balance sheets, the calculation of diluted loss per share requires that, to the extent the average market price of the underlying shares for the reporting period exceeds the exercise price of the warrants and the presumed exercise of the warrants is dilutive to loss per share for the period, an adjustment is made to net loss used in the calculation to remove the change in fair value of the warrants from the numerator for the period. Likewise, an adjustment to the denominator is required to reflect the related dilutive shares, if any, under the treasury stock method. The following outstanding shares of common stock equivalents were excluded from the computations of diluted loss per share of common stock attributable to common stockholders for the periods presented as the effect of including such securities would be anti-dilutive. March 31, 2022 March 31, 2021 Anti-dilutive common stock equivalents: Number of Shares Redeemable convertible series 1 preferred stock 4,520,000 4,520,000 Warrants to purchase common stock 5,750,000 11,616,080 Private placement option — 9,675,000 Options to purchase common stock 2,064,537 1,400,470 Unvested shares of restricted stock units 10,500 262,010 Total anti-dilutive common stock equivalents 12,345,037 27,473,560

FAIR VALUE MEASUREMENTS AND INV

FAIR VALUE MEASUREMENTS AND INVESTMENT SECURITIES	3 Months Ended
	Mar. 31, 2022
Fair Value Disclosures [Abstract]
FAIR VALUE MEASUREMENTS AND INVESTMENT SECURITIES	FAI R VALU E MEASUREMENTS AND INVESTMENT SECURITIES Fair Value of Financial Instruments Fair value is defined as an exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. As such, fair value is a market-based measurement that should be determined based on assumptions that market participants would use in pricing an asset or liability. As a basis for considering such assumptions, a fair value hierarchy has been established that prioritizes the inputs used to measure fair value. The hierarchy gives the highest priority to unadjusted quoted prices in active markets for identical assets or liabilities (Level 1 measurement) and the lowest priority to unobservable inputs (Level 3 measurement). These inputs are classified into the following hierarchy: Level 1 Inputs - quoted prices (unadjusted) in active markets for identical assets that the reporting entity has the ability to access at the measurement date; Level 2 Inputs - inputs other than quoted prices included within Level 1 that are observable for the asset, either directly or indirectly; and Level 3 Inputs - unobservable inputs for the assets. The categorization of a financial instrument within the valuation hierarchy is based upon the lowest level of input that is significant to the fair value measurement. The Company believes the recorded values of its financial instruments, including cash and cash equivalents, accounts payable, and accrued liabilities approximate their fair values due to the short-term nature of these instruments. Investment Securities The following table presents the Company’s investment securities (including, if applicable, those classified on the Company’s balance sheet as cash equivalents) that are measured at fair value on a recurring basis as of March 31, 2022 and December 31, 2021: Fair Value at March 31, 2022 Fair Value at December 31, 2021 (in thousands) Level 1 Level 2 Level 3 Level 1 Level 2 Level 3 Cash equivalents: Money market funds $ 34,999 $ — $ — $ 42,487 $ — $ — Total cash equivalents $ 34,999 $ — $ — $ 42,487 $ — $ — As of March 31, 2022 and December 31, 2021, an additional $1.5 million of restricted cash on the Company's balance sheet is held in a money market fund and would be considered a level 1 measurement. Money market funds are valued based on various observable inputs such as benchmark yields, reported trades, broker/dealer quotes, benchmark securities and bids. Warrant Derivative Liability and Private Placement Option Liability The Company's financial liabilities recorded at fair value on a recurring basis include the fair values of the warrant derivative liability and the private placement option liability prior to its derecognition in December 2021. Inputs used to determine estimated fair value (Level 3) of the warrants include the fair value of the underlying stock relative to the warrant exercise price at the valuation measurement date, volatility of the price of the underlying stock, the expected term of the warrants, and risk-free interest rates. The fair values of the warrant derivative liability and the private placement option liability, prior to its derecognition in December 2021, are classified as current liabilities in the accompanying condensed consolidated balance sheets. These liabilities will be shown as current liabilities on the balance sheet when it is deemed more probable than not by management to be exercised within one year. On December 4, 2021, the Company entered into a Securities Purchase Agreement (the “2021 Securities Purchase Agreement”), pursuant to which certain of the investors irrevocably waived the right to cause the Company to conduct the “First Closing” and “Second Closing” under the private placement option contained in the 2019 Securities Purchase Agreement (each term as defined in the 2019 Securities Purchase Agreement). The Company derecognized the private placement option liability of $2.8 million during the fourth quarter of 2021, out of which $2.6 million was recorded as gain on change in the fair value in the accompanying statements of operations and comprehensive loss, and $0.2 million was recorded as additional paid-in capital in the accompanying balance sheets. The fair value of the warrants has been estimated with the following weighted-average assumptions, including the most sensitive input, volatility: March 31, 2022 December 31, 2021 Risk-free interest rate 2.40% 1.22% Volatility 92.00% 94.00% Expected term (years) 4.38 4.64 The following table provides the warrant derivative liability reported at fair value and measured on a recurring basis: Fair Value at March 31, 2022 Fair Value at December 31, 2021 (in thousands) Level 1 Level 2 Level 3 Level 1 Level 2 Level 3 Warrant derivative liability $ — $ — $ 4,410 $ — $ — $ 2,773 Total fair value $ — $ — $ 4,410 $ — $ — $ 2,773 The ending balance of the Level 3 financial instruments presented above represents the Company's best estimate of valuation and may not be substantiated by comparison to independent markets and, in many cases, could not be realized in immediate settlement of the instruments.

LEASES

LEASES	3 Months Ended
	Mar. 31, 2022
Leases [Abstract]
LEASES	LEASES The Company entered into two agreements and exited its Houston and South San Francisco office locations during the first quarter of 2021 and, therefore, did not have any lease liabilities as of March 31, 2022. In connection with the lease termination and exit of the Houston office, a third party also acquired all of the property and equipment associated with the location. The consideration included an unsecured promissory note of $0.2 million with a simple interest of 4% per annum, which is due and payable on or before June 30, 2022. Components of lease cost are as follows: Three Months Ended (in thousands) March 31, 2022 March 31, 2021 Finance lease cost: Amortization of leased asset $ — $ 10 Interest on lease liabilities — 4 Operating lease cost — 54 Short-term lease cost — 52 Total lease cost $ — $ 120

PUBLIC OFFERING AND PRIVATE PLA

PUBLIC OFFERING AND PRIVATE PLACEMENT	3 Months Ended
	Mar. 31, 2022
Statement of Stockholders' Equity [Abstract]
PUBLIC OFFERING AND PRIVATE PLACEMENT	PUBLIC OFFERING AND PRIVATE PLACEMENT December 2021 Private Placement On December 4, 2021, the Company entered into a Securities Purchase Agreement (the “2021 Securities Purchase Agreement”) with certain institutional investors, pursuant to which the Company issued pre-funded warrants to purchase an aggregate of 20,559,210 shares of its common stock and accompanying common warrants to purchase an aggregate of 2,055,920 shares of its common stock. Each pre-funded warrant to purchase one share of common stock was sold together with one warrant to purchase one-tenth of one share of common stock at a combined unit price of $1.7024. The pre-funded warrants were immediately exercisable at an exercise price of $0.0001 per share of common stock. The accompanying common warrants were immediately exercisable at an exercise price of $1.69 per share of common stock and will expire seven years from the date of issuance. The gross proceeds to the Company from the private placement were approximately $35.0 million before deducting placement agent commissions and offering expenses payable by the Company, excluding any proceeds that may be received upon exercise of the accompanying warrants. In addition, pursuant to the 2021 Securities Purchase Agreement, purchasers 2019 Securities Purchase Agreement (defined below) irrevocably waived the right to cause the Company to conduct the “First Closing” and “Second Closing” under the 2019 Securities Purchase Agreement (each term as defined in the 2019 Securities Purchase Agreement), which releases the Company of potential cash or equity obligations. November 2020 Underwritten Offering On November 2, 2020, the Company closed an underwritten offering of 1,040,000 shares of its common stock, pre-funded warrants to purchase 3,109,378 shares of its common stock, and accompanying common warrants to purchase up to an aggregate of 4,149,378 shares of its common stock. Each share of common stock and pre-funded warrant to purchase one share of common stock was sold together with a common warrant to purchase one share of common stock. The public offering price of each share of common stock and accompanying common warrant was $6.025 and $6.024 for each pre-funded warrant. The pre-funded warrants were immediately exercisable at a price of $0.001 per share of common stock. The common warrants were immediately exercisable at an exercise price of $6.50 per share of common stock and will expire five years from the date of issuance. The shares of common stock and pre-funded warrants, and the accompanying common warrants, were issued separately and were immediately separable upon issuance. The gross proceeds to the Company were approximately $25.0 million before deducting underwriting discounts and commissions and other offering expenses. August 2019 Public Offering On August 16, 2019, the Company entered into an underwriting agreement (the “Underwriting Agreement”) with Jefferies LLC and Wells Fargo Securities, LLC, as representatives of the several underwriters named therein (the “Underwriters”), relating to an underwritten public offering (the “Offering”) of 575,000 shares of the Series 1 Redeemable Convertible Non-Voting Preferred Stock of the Company (the “Series 1 Preferred Stock”) and warrants (the “Public Warrants”) to purchase up to 5,750,000 shares of its common stock. Each share of Series 1 Preferred Stock was being sold together with a warrant to purchase 10 shares of common stock at a combined price to the public of $100.00. Under certain circumstances, each warrant to purchase 10 shares of common stock will be exercisable, at the irrevocable election of the holder, for one share of Series 1 Preferred Stock. The offering closed on August 21, 2019, and the net proceeds to the Company from the Offering were approximately $53.8 million after deducting underwriting discounts and commissions and estimated offering expenses payable by the Company, and excluding any proceeds that the Company may receive upon exercise of the Public Warrants. All of the Public Warrants sold in the Offering have an exercise price of $13.00 per share of common stock or, in certain circumstances, for $130.00 per share of Series 1 Preferred Stock, subject to proportional adjustments in the event of stock splits or combinations or similar events. The Public Warrants were immediately exercisable upon issuance, provided that the holder is prohibited, subject to certain exceptions, from exercising a warrant for shares of common stock to the extent that immediately prior to or after giving effect to such exercise, the holder, together with its affiliates and other attribution parties, would own more than 9.99% of the total number of shares of common stock then issued and outstanding, which percentage may be changed at the holder’s election to a lower percentage at any time or to a higher percentage not to exceed 19.99% upon 61 days’ notice to the Company. The Public Warrants will expire on August 21, 2026, unless exercised prior to that date. The following table reflects the fair value roll forward reconciliation of the warrant derivative liabilities for the period ended March 31, 2022: (in thousands) Warrant Derivative Liability Balance, December 31, 2021 $ 2,773 Change in fair value 1,637 Balance, March 31, 2022 $ 4,410 Private Placement On August 16, 2019, the Company entered into a Securities Purchase Agreement (the “Securities Purchase Agreement”) with certain institutional investors named therein (the “Purchasers”), pursuant to which the Company agreed to issue in a private placement (i) 350,000 shares of its Series 2 Redeemable Convertible Non-Voting Preferred Stock (the “Series 2 Preferred Stock”), at a purchase price of $100.00 per share, and related warrants (the “Private Warrants”) to purchase up to 2,800,000 shares of common stock at an exercise price of $10.00 per share, and (ii) 250,000 shares of its Series 3 Redeemable Convertible Non-Voting Preferred Stock (the “Series 3 Preferred Stock” and, together with the Series 1 Preferred Stock and Series 2 Preferred Stock, the “Preferred Stock”), at a purchase price of $140.00 per share, and related warrants (also, “Private Warrants”) to purchase up to 875,000 shares of common stock at an exercise price of $14.00 per share. The Company received $11.2 million in net option fee proceeds, net of offering costs, upon the execution of the 2019 Securities Purchase Agreement. Pursuant to the 2021 Securities Purchase Agreement entered into on December 4, 2021, the Purchasers irrevocably waived the right to purchase such securities, and the Company derecognized the private placement option liability for the year ended December 31, 2021. The Company is no longer obligated to issue the Series 2 Preferred Stock, Series 3 Preferred Stock, or any associated Private Warrants. A summary of warrants outstanding and exercisable as of March 31, 2022 is as follows: Year Issued Warrants Outstanding and Exercisable Weighted Average Remaining Weighted Average Exercise Price (in years) (per share) 2019 5,750,000 4.39 $ 13.00 2020 4,149,378 3.59 $ 6.50 2020 1 1,659,752 — $ — 2021 2,055,920 6.69 $ 1.69 2021 2 20,559,210 — $ — 34,174,260

REDEEMABLE CONVERTIBLE PREFERRE

REDEEMABLE CONVERTIBLE PREFERRED STOCK	3 Months Ended
	Mar. 31, 2022
Equity [Abstract]
REDEEMABLE CONVERTIBLE PREFERRED STOCK	REDEEMABLE CONVERTIBLE PREFERRED STOCK In August 2019, the Company sold Series 1 Preferred Stock pursuant to the Offering. The Company has 10,000,000 authorized shares of preferred stock with a par value of $0.01 per share, of which the Company has designated 1,517,500 shares as Series 1 Preferred Stock, 350,000 shares as Series 2 Preferred Stock and 250,000 shares as Series 3 Preferred Stock. There were 452,000 shares of Series 1 Preferred Stock and no shares of Series 2 or Series 3 Preferred Stock issued and outstanding as of March 31, 2022. As of March 31, 2022, the Company classified the Series 1 Preferred Stock as mezzanine equity, because the Series 1 Preferred Stock is redeemable at the option of the holders upon passage of time, which is outside of the Company’s control to prevent. Subsequent adjustment of the amount presented in mezzanine equity to its redemption amount is necessary unless it is probable that the instrument will not become redeemable. The Series 1 Preferred Stock is not redeemable at March 31, 2022, and is only currently redeemable upon a fundamental change in a redemption price. The Company does not believe a fundamental change is considered probable until it occurs. As (i) a fundamental change is not probable, and (ii) the occurrence of Transition Date (defined below) is probable, the Company did not accrete the Series 1 Preferred Stock to its redemption amount because it is probable the instrument will not become redeemable. Optional Conversion Each share of Preferred Stock is initially convertible into 10 shares of Common Stock. The conversion price at which Preferred Stock may be converted into shares of common stock, is subject to adjustment in connection with certain specified events. Redemption Until the applicable Transition Date (defined below), at any time on or after the date that is the fifth (5th) anniversary of the initial issue date of the applicable series of preferred stock, all or any portion of the preferred stock is redeemable at the option of the holder at a redemption price of $100.00 per share (for Series 1 Preferred Stock). The “Transition Date” means the first date following August 21, 2021, on which each of the Conditions (as defined below) is met. The “Conditions” mean: (1) the closing price of the Company’s common stock has been equal to or exceeded $25.00 per share for 180 calendar days (for determining if the Conditions are met for the Series 1 preferred stock) for 180 calendar days; (2) the 50-day average trading volume of the Company’s common stock on the Nasdaq stock market is greater than 50,000 shares; and (3) a Phase 3 or Phase 2 pivotal clinical trial for one of the Company’s CAR-T product candidates has been initiated, meaning that at least one clinical trial site has been activated. Dividends Shares of Preferred Stock will be entitled to receive dividends equal to (on an as-if-converted-to-common stock basis), and in the same form and manner as, dividends actually paid on shares of common stock. Liquidation Until the applicable Transition Date, in the event of a liquidation, dissolution, winding up or deemed liquidation, holders of the Preferred Stock will receive a payment equal to the applicable per share purchase price of their Preferred Stock before any proceeds are distributed to the holders of Common Stock. The liquidation preferences, protective voting provisions and redemption rights of the Preferred Stock will terminate upon the occurrence of certain events. Voting Shares of Preferred Stock will generally have no voting rights, except to the extent expressly provided in the Company’s certificate of incorporation or as otherwise required by law.

SHARE-BASED COMPENSATION PLANS

SHARE-BASED COMPENSATION PLANS	3 Months Ended
	Mar. 31, 2022
Share-based Payment Arrangement [Abstract]
SHARE-BASED COMPENSATION PLANS	SHARE-BASED COMPENSATION PLANS Share-Based Compensation Plans The Company has five share-based compensation plans, including the 2019 Equity Incentive Plan (the “2019 Plan”), which was adopted in June 2019. Each plan authorizes the granting of shares of common stock and/or options to purchase common stock to employees and directors of the Company, as well as non-employee consultants, and allows the holder of the option to purchase common stock at a stated exercise price. The only plan under which the Company may currently grant equity awards is the 2019 Equity Incentive Plan although there remain outstanding awards under the other four plans. Options vest according to the terms of the grant, which may be immediately or based on the passage of time, generally over two Share-Based Compensation Expense Share-based compensation expense by classification for the three months ended March 31, 2022 and 2021 are as follows: Three Months Ended (in thousands) March 31, 2022 March 31, 2021 Research and development $ 294 $ 263 General and administrative 305 640 Total $ 599 $ 903

COMMITMENTS AND CONTINGENCIES

COMMITMENTS AND CONTINGENCIES	3 Months Ended
	Mar. 31, 2022
Commitments and Contingencies Disclosure [Abstract]
COMMITMENTS AND CONTINGENCIES	COMMITMENTS AND CONTINGENCIES Co-Development and Co-Commercialization Agreement - Adaptimmune Therapeutics plc On December 16, 2016, the Company entered into a Co-Development and Co-Commercialization Agreement with and Adaptimmune Therapeutics plc (Adaptimmune) in order to facilitate a staged collaboration to evaluate, develop and commercialize next generation T cell therapies. Under the Agreement, the parties agreed to evaluate the Company’s GoTCR technology (inducible MyD88/CD40 co-stimulation, or iMC) with Adaptimmune’s affinity-optimized SPEAR® T cells for the potential to create enhanced TCR product candidates. Depending on results of the preclinical proof-of-concept phase, the parties expect to progress to a two-target co-development and co-commercialization phase. To the extent necessary, and in furtherance of the parties’ proof-of-concept and co-development efforts, the parties granted each other a royalty-free, non-transferable, non-exclusive license covering their respective technologies for purposes of facilitating such proof-of-concept and co-development efforts. In addition, as to covered therapies developed under the agreement, the parties granted each other a reciprocal exclusive license for the commercialization of such therapies. With respect to any joint commercialization of a covered therapy, the parties agreed to negotiate in good faith the commercially reasonable terms of a co-commercialization agreement. The parties also agreed that any such agreement shall provide for, among other things, equal sharing of the costs of any such joint commercialization and the calculation of profit shares as set forth in the Agreement. The Agreement will expire on a country-by-country basis once the parties cease commercialization of the T cell therapies covered by the Agreement, unless earlier terminated by either party for material breach, non-performance or cessation of development, bankruptcy/insolvency, or failure to progress to co-development phase. License Agreement - Baylor In 2008, 2010, 2014 and 2016, the Company and Baylor College of Medicine (“BCM”) entered into license agreements pursuant to which the Company obtained exclusive rights to certain technologies and patent rights owned by BCM. Under the 2014 license agreement, the Company is required to pay BCM a low annual maintenance fee on each anniversary of the agreement date. The Company is also required to make royalty payments in the low single digits, subject to certain annual minimums, on net sales of products covered by the license and, to the extent the Company enters into a sublicensing agreement relating to a licensed product, the Company is also required to pay BCM a percentage in the low double-digits on all non-royalty income received from sublicensing revenue. License Agreement - Agensys, Inc. On December 10, 2015, the Company and Agensys, Inc. (“Agensys”), entered into a license agreement (the “Agensys Agreement”), pursuant to which (i) Agensys granted the Company, within the field of cell and gene therapy of diseases in humans, an exclusive, worldwide license and sublicense to its patent rights directed to prostate stem cell antigen 1 (“PSCA”) and related antibodies, and (ii) the Company granted Agensys a non-exclusive, fully paid license to the Company’s patents directed to inventions that were made by the Company in the course of developing the Company’s licensed products, solely for use with Agensys therapeutic products containing a soluble antibody that binds to PSCA or, to the extent not based upon the Company’s other proprietary technology, to non-therapeutic applications of antibodies not used within the field. As consideration for the rights granted to the Company under the Agreement, the Company agreed to pay to Agensys a non-refundable upfront fee of $3.0 million, which was included in license fee expense. The Company is also required to make aggregate milestone payments to Agensys of up to (i) $5.0 million upon the first achievement of certain specified clinical milestones for its licensed products, (ii) $50.0 million upon the achievement of certain specified clinical milestones for each licensed product, and (iii) $75.0 million upon the achievement of certain sales milestones for each licensed product. The Agreement additionally provides that the Company will pay to Agensys a royalty that ranges from the mid to high single digits based on the level of annual net sales of licensed products by the Company, its affiliates or permitted sublicensees. The royalty payments are subject to reduction under specified circumstances. These milestone and royalty payments will be expensed as incurred. Under the Agreement, Agensys also was granted the option to obtain an exclusive license, on a product-by-product basis, from the Company to commercialize in Japan each licensed product developed under the Agensys Agreement that has completed a phase 2 clinical trial. As to each such licensed product, if Agensys or its affiliate, Astellas Pharma, Inc., exercises the option, the Agensys Agreement provides that the Company will be paid an option exercise fee of $5.0 million. In addition, the Agensys Agreement provides that the Company will be paid a royalty that ranges from the mid to high single digits based on the level of annual net sales in Japan of each such licensed product. If the option is exercised, the aggregate milestone payments payable by the Company to Agensys, described above with respect to each licensed product, would be reduced by up to an aggregate of $65.0 million upon the achievement of certain specified clinical and sales milestones. The Agensys Agreement will terminate upon the expiration of the last royalty term for the products covered by the Agensys Agreement, which is the earlier of (i) the date of expiration or abandonment of the last valid claim within the licensed patent rights covering any licensed products under the Agreement, (ii) the expiration of regulatory exclusivity as to a licensed product, and (iii) 10 years after the first commercial sale of a licensed product. Either party may terminate the Agensys Agreement upon a material breach by the other party that remains uncured following 60 days after the date of written notice of such breach (or 30 days if such material breach is related to failure to make payment of amounts due under the Agensys Agreement) or upon certain insolvency events. In addition, Agensys may terminate the Agensys Agreement immediately upon written notice to the Company if the Company or any of its affiliates or permitted sublicensees commences an interference proceeding or challenges the validity or enforceability of any of Agensys’ patent rights. License Agreement - BioVec On June 10, 2015, the Company and BioVec Pharma, Inc. (“BioVec”) entered into a license agreement (the “BioVec Agreement”) pursuant to which BioVec agreed to supply the Company with certain proprietary cell lines and granted to the Company a non-exclusive, worldwide license to certain of its patent rights and related know-how related to such proprietary cell lines. As consideration for the products supplied and rights granted to the Company under the BioVec Agreement, the Company agreed to pay to BioVec an upfront fee of $100,000 within ten ten Litigation On May 29, 2019, Bellicum was served with a second amended complaint indicating that the Company had been added as an additional defendant in an ongoing civil tort lawsuit, captioned Kelly v. Children’s Hospital of Los Angeles et al., filed in the Los Angeles County Superior Court, Case No. BC681477. On July 10, 2019 plaintiffs filed a third amended complaint seeking unspecified monetary damages including punitive damages and alleging claims for wrongful death, negligence, breach of fiduciary duty, fraud, medical battery on decedent, medical battery on individual plaintiffs, products liability - failure to warn, breach of express warranty and products liability design or manufacturing defect. Bellicum filed a demurrer and motion to strike plaintiffs’ third amended complaint, which were granted in part on August 5, 2020 with the Court dismissing (without prejudice) all claims against Bellicum with the exception of the breach of express warranty and products liability design or manufacturing defect causes of action. The Court also granted Bellicum’s motion to strike plaintiffs’ claim for punitive damages. On September 15, 2020, plaintiffs filed a fourth amended complaint alleging the same causes of action and damages against Bellicum as were pled in the third amended complaint. On November 3, 2020, Bellicum filed a demurrer and motion to strike the fourth amended complaint, which is set for hearing on May 19, 2022.

ORGANIZATION, BASIS OF PRESEN_2

ORGANIZATION, BASIS OF PRESENTATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)	3 Months Ended
	Mar. 31, 2022
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	Basis of PresentationThe accompanying unaudited condensed financial statements have been prepared in conformity with the authoritative U.S. generally accepted accounting principles (“GAAP”) for interim financial information and pursuant to Form 10-Q and Article 10 of Regulation S-X of the Securities and Exchange Commission (“SEC”).
Use of Estimates	Use of Estimates The preparation of the interim condensed consolidated financial statements in accordance with GAAP requires management to make certain estimates and judgments that affect the reported amounts of assets, liabilities, and expenses. Actual results could differ from those estimates.
Cash, Cash Equivalents, and Restricted Cash	Cash, Cash Equivalents and Restricted Cash The Company considers all short-term, highly liquid investments with maturity of three months or less from the date of purchase and that can be liquidated without prior notice or penalty, to be cash equivalents.
Net Loss and Net Loss per Share of Common Stock Attributable to Common Stockholders	Net Loss and Net Loss per Share of Common Stock Attributable to Common Stockholders Basic net loss per share attributable to common stockholders is calculated by dividing the net loss attributable to common stockholders by the weighted-average number of shares of common stock outstanding during the period without consideration for common stock equivalents. Diluted earnings per share is based on the more dilutive method between the two-class method and the treasury stock method and includes the effect from potential issuance of ordinary shares, such as shares issuable pursuant to the conversion of preferred stock to common stock, exercise of warrants to purchase common stock, exercise of stock options, and vesting of restricted stock units. For periods of net loss, diluted net loss per share is calculated similarly to basic net loss per share. For warrants that are recorded as a liability in the accompanying condensed consolidated balance sheets, the calculation of diluted loss per share requires that, to the extent the average market price of the underlying shares for the reporting period exceeds the exercise price of the warrants and the presumed exercise of the warrants is dilutive to loss per share for the period, an adjustment is made to net loss used in the calculation to remove the change in fair value of the warrants from the numerator for the period. Likewise, an adjustment to the denominator is required to reflect the related dilutive shares, if any, under the treasury stock method.
Fair Value Measurements	Fair value is defined as an exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. As such, fair value is a market-based measurement that should be determined based on assumptions that market participants would use in pricing an asset or liability. As a basis for considering such assumptions, a fair value hierarchy has been established that prioritizes the inputs used to measure fair value. The hierarchy gives the highest priority to unadjusted quoted prices in active markets for identical assets or liabilities (Level 1 measurement) and the lowest priority to unobservable inputs (Level 3 measurement). These inputs are classified into the following hierarchy: Level 1 Inputs - quoted prices (unadjusted) in active markets for identical assets that the reporting entity has the ability to access at the measurement date; Level 2 Inputs - inputs other than quoted prices included within Level 1 that are observable for the asset, either directly or indirectly; and Level 3 Inputs - unobservable inputs for the assets. The categorization of a financial instrument within the valuation hierarchy is based upon the lowest level of input that is significant to the fair value measurement. The Company believes the recorded values of its financial instruments, including cash and cash equivalents, accounts payable, and accrued liabilities approximate their fair values due to the short-term nature of these instruments.

ORGANIZATION, BASIS OF PRESEN_3

ORGANIZATION, BASIS OF PRESENTATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Tables)	3 Months Ended
	Mar. 31, 2022
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Schedule of Cash and Cash Equivalents	The following table provides a reconciliation of cash, cash equivalents and restricted cash reported within the balance sheets that sum to the total of the same such amounts shown in the statements of cash flows. (in thousands) March 31, 2022 December 31, 2021 Cash and cash equivalents $ 39,769 $ 46,156 Restricted cash 1,501 1,501 Total cash, cash equivalents and restricted cash shown in the statements of cash flows $ 41,270 $ 47,657
Cash, Cash Equivalents and Restricted Cash, Reconciliation	The following table provides a reconciliation of cash, cash equivalents and restricted cash reported within the balance sheets that sum to the total of the same such amounts shown in the statements of cash flows. (in thousands) March 31, 2022 December 31, 2021 Cash and cash equivalents $ 39,769 $ 46,156 Restricted cash 1,501 1,501 Total cash, cash equivalents and restricted cash shown in the statements of cash flows $ 41,270 $ 47,657
Accrued Expenses and Other Current Liabilities	Accrued expenses and other liabilities consist of the following: (in thousands) March 31, 2022 December 31, 2021 Accrued payroll $ 166 $ 320 Accrued patient treatment costs 1,393 2,086 Accrued clinical research costs 663 479 Accrued manufacturing costs 388 328 Accrued professional services 417 305 Accrued other 320 331 Total accrued expenses and other current liabilities $ 3,347 $ 3,849
Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share	The following outstanding shares of common stock equivalents were excluded from the computations of diluted loss per share of common stock attributable to common stockholders for the periods presented as the effect of including such securities would be anti-dilutive. March 31, 2022 March 31, 2021 Anti-dilutive common stock equivalents: Number of Shares Redeemable convertible series 1 preferred stock 4,520,000 4,520,000 Warrants to purchase common stock 5,750,000 11,616,080 Private placement option — 9,675,000 Options to purchase common stock 2,064,537 1,400,470 Unvested shares of restricted stock units 10,500 262,010 Total anti-dilutive common stock equivalents 12,345,037 27,473,560

FAIR VALUE MEASUREMENTS AND I_2

FAIR VALUE MEASUREMENTS AND INVESTMENT SECURITIES (Tables)	3 Months Ended
	Mar. 31, 2022
Fair Value Disclosures [Abstract]
Summary of Assets Measured at Fair Value on a Recurring Basis	The following table presents the Company’s investment securities (including, if applicable, those classified on the Company’s balance sheet as cash equivalents) that are measured at fair value on a recurring basis as of March 31, 2022 and December 31, 2021: Fair Value at March 31, 2022 Fair Value at December 31, 2021 (in thousands) Level 1 Level 2 Level 3 Level 1 Level 2 Level 3 Cash equivalents: Money market funds $ 34,999 $ — $ — $ 42,487 $ — $ — Total cash equivalents $ 34,999 $ — $ — $ 42,487 $ — $ — The following table provides the warrant derivative liability reported at fair value and measured on a recurring basis: Fair Value at March 31, 2022 Fair Value at December 31, 2021 (in thousands) Level 1 Level 2 Level 3 Level 1 Level 2 Level 3 Warrant derivative liability $ — $ — $ 4,410 $ — $ — $ 2,773 Total fair value $ — $ — $ 4,410 $ — $ — $ 2,773
Schedule of Derivative Liabilities at Fair Value	The fair value of the warrants has been estimated with the following weighted-average assumptions, including the most sensitive input, volatility: March 31, 2022 December 31, 2021 Risk-free interest rate 2.40% 1.22% Volatility 92.00% 94.00% Expected term (years) 4.38 4.64 The following table reflects the fair value roll forward reconciliation of the warrant derivative liabilities for the period ended March 31, 2022: (in thousands) Warrant Derivative Liability Balance, December 31, 2021 $ 2,773 Change in fair value 1,637 Balance, March 31, 2022 $ 4,410

LEASES (Tables)

LEASES (Tables)	3 Months Ended
	Mar. 31, 2022
Leases [Abstract]
Components of Lease Cost	Components of lease cost are as follows: Three Months Ended (in thousands) March 31, 2022 March 31, 2021 Finance lease cost: Amortization of leased asset $ — $ 10 Interest on lease liabilities — 4 Operating lease cost — 54 Short-term lease cost — 52 Total lease cost $ — $ 120

PUBLIC OFFERING AND PRIVATE P_2

PUBLIC OFFERING AND PRIVATE PLACEMENT (Tables)	3 Months Ended
	Mar. 31, 2022
Statement of Stockholders' Equity [Abstract]
Schedule of Derivative Liabilities at Fair Value	The fair value of the warrants has been estimated with the following weighted-average assumptions, including the most sensitive input, volatility: March 31, 2022 December 31, 2021 Risk-free interest rate 2.40% 1.22% Volatility 92.00% 94.00% Expected term (years) 4.38 4.64 The following table reflects the fair value roll forward reconciliation of the warrant derivative liabilities for the period ended March 31, 2022: (in thousands) Warrant Derivative Liability Balance, December 31, 2021 $ 2,773 Change in fair value 1,637 Balance, March 31, 2022 $ 4,410
Summary of Warrants Outstanding and Exercisable	A summary of warrants outstanding and exercisable as of March 31, 2022 is as follows: Year Issued Warrants Outstanding and Exercisable Weighted Average Remaining Weighted Average Exercise Price (in years) (per share) 2019 5,750,000 4.39 $ 13.00 2020 4,149,378 3.59 $ 6.50 2020 1 1,659,752 — $ — 2021 2,055,920 6.69 $ 1.69 2021 2 20,559,210 — $ — 34,174,260

SHARE-BASED COMPENSATION PLANS

SHARE-BASED COMPENSATION PLANS (Tables)	3 Months Ended
	Mar. 31, 2022
Share-based Payment Arrangement [Abstract]
Share-Based Compensation Expense by Classification	Share-based compensation expense by classification for the three months ended March 31, 2022 and 2021 are as follows: Three Months Ended (in thousands) March 31, 2022 March 31, 2021 Research and development $ 294 $ 263 General and administrative 305 640 Total $ 599 $ 903

ORGANIZATION, BASIS OF PRESEN_4

ORGANIZATION, BASIS OF PRESENTATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Narrative (Details)	Mar. 15, 2021USD ($)	Apr. 30, 2020USD ($)	Mar. 31, 2022USD ($)subsidiary	Mar. 31, 2021USD ($)	Dec. 31, 2021USD ($)	Mar. 26, 2021USD ($)	Feb. 26, 2021USD ($)
Class of Stock [Line Items]
Number of wholly-owned subsidiaries formed | subsidiary			2
Accumulated deficit			$ (558,014,000)		$ (550,452,000)
Cash and cash equivalents			39,769,000		$ 46,156,000
Restricted cash			1,500,000
Operating lease liability			0
Loss on dispositions, net			$ 0	$ 464,000
U.S. Manufacturing Facility
Class of Stock [Line Items]
Cash proceeds subject to escrow provisions		$ 1,500,000
Leased R&D Facility In Houston, Texas
Class of Stock [Line Items]
Amount paid upon closing of asset sale							$ 1,100,000
Lease exit agreement, cash receivable							900,000
Lease exist agreement, note receivable							$ 200,000
San Francisco Office Space
Class of Stock [Line Items]
Lease termination fee	$ 900,000
Security deposit	$ 200,000
Operating lease, right-of-use asset						$ 600,000
Operating lease liability						1,000,000
Loss on dispositions, net				$ 500,000
San Francisco Office Space | Equipment
Class of Stock [Line Items]
Operating lease, right-of-use asset						$ 100,000

ORGANIZATION, BASIS OF PRESEN_5

ORGANIZATION, BASIS OF PRESENTATION, AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Cash Reconciliation (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021	Mar. 31, 2021	Dec. 31, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Cash and cash equivalents	$ 39,769	$ 46,156
Restricted cash	1,501	1,501
Total cash, cash equivalents and restricted cash shown in the statements of cash flows	$ 41,270	$ 47,657	$ 29,583	$ 36,996

ORGANIZATION, BASIS OF PRESEN_6

ORGANIZATION, BASIS OF PRESENTATION, AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Accrued Expenses and Other Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Accrued payroll	$ 166	$ 320
Accrued patient treatment costs	1,393	2,086
Accrued clinical research costs	663	479
Accrued manufacturing costs	388	328
Accrued professional services	417	305
Accrued other	320	331
Total accrued expenses and other current liabilities	$ 3,347	$ 3,849

ORGANIZATION, BASIS OF PRESEN_7

ORGANIZATION, BASIS OF PRESENTATION, AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Anti-dilutive Shares Excluded From Earnings Per Share Calculations (Details) - shares	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Total common stock equivalents (in shares)	12,345,037	27,473,560
Redeemable convertible series 1 preferred stock
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Total common stock equivalents (in shares)	4,520,000	4,520,000
Warrants to purchase common stock
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Total common stock equivalents (in shares)	5,750,000	11,616,080
Private placement option
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Total common stock equivalents (in shares)	0	9,675,000
Options to purchase common stock
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Total common stock equivalents (in shares)	2,064,537	1,400,470
Unvested shares of restricted stock units
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Total common stock equivalents (in shares)	10,500	262,010

FAIR VALUE OF MEASUREMENTS AND

FAIR VALUE OF MEASUREMENTS AND INVESTMENT SECURITIES - Assets Measured on Recurring Basis (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Level 1
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Total cash equivalents	$ 34,999	$ 42,487
Level 1 | Money market funds
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Total cash equivalents	34,999	42,487
Restricted cash equivalents	1,500	1,500
Level 2
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Total cash equivalents	0	0
Level 2 | Money market funds
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Total cash equivalents	0	0
Level 3
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Total cash equivalents	0	0
Level 3 | Money market funds
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Total cash equivalents	$ 0	$ 0

FAIR VALUE OF MEASUREMENTS AN_2

FAIR VALUE OF MEASUREMENTS AND INVESTMENT SECURITIES - Fair Value of Warrants (Details) - Warrant Derivative Liability - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2022	Dec. 31, 2021
Derivative [Line Items]
Private placement option liability		$ 2.8
Gain on change in the fair value	$ 2.6
Additional paid in capital	$ 0.2
Risk-free interest rate	2.40%	1.22%
Volatility	92.00%	94.00%
Expected term (years)	4 years 4 months 17 days	4 years 7 months 20 days

FAIR VALUE OF MEASUREMENTS AN_3

FAIR VALUE OF MEASUREMENTS AND INVESTMENT SECURITIES - Derivative Liabilities Reported at Fair Value (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Warrant derivative liability	$ 4,410	$ 2,773
Level 1
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Warrant derivative liability	0	0
Total fair value	0	0
Level 2
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Warrant derivative liability	0	0
Total fair value	0	0
Level 3
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Warrant derivative liability	4,410	2,773
Total fair value	$ 4,410	$ 2,773

LEASES - Narrative (Details)

LEASES - Narrative (Details)	3 Months Ended
	Mar. 31, 2022USD ($)	Mar. 31, 2021lease_agreement
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of lease agreements entered into during period | lease_agreement		2
Operating lease liability	$ 0
Finance lease liability	0
Discontinued Operations, Disposed of by Sale | Houston Office
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Lease exist agreement, note receivable	$ 200,000
Simple interest	4.00%

LEASES - Components of Lease Co

LEASES - Components of Lease Cost (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Finance lease cost:
Amortization of leased asset	$ 0	$ 10
Interest on lease liabilities	0	4
Operating lease cost	0	54
Short-term lease cost	0	52
Total lease cost	$ 0	$ 120

PUBLIC OFFERING AND PRIVATE P_3

PUBLIC OFFERING AND PRIVATE PLACEMENT - Narrative (Details) - USD ($) $ / shares in Units, $ in Millions	Dec. 04, 2021	Nov. 02, 2020	Aug. 21, 2019	Aug. 16, 2019	Aug. 31, 2019	Dec. 31, 2019	Mar. 31, 2022	Dec. 31, 2021
Class of Stock [Line Items]
Common stock, par value (in dollars per share)							$ 0.01	$ 0.01
Common stock, issued (in shares)							8,676,903	8,497,025
Proceeds from issuance of redeemable convertible preferred stock in a public offering, net			$ 53.8
Proceeds upon entering into private placement agreement						$ 11.2
Series 1 Preferred
Class of Stock [Line Items]
Shares issuable per warrants (in shares)							10
Price per share (in dollars per share)							$ 100
Number of shares of common stock sold in offering (in shares)					1,517,500
December 2021 Private Placement
Class of Stock [Line Items]
Shares issuable per warrants (in shares)	20,559,210
Warrants to purchase aggregate shares of common stock (in shares)	2,055,920
Shares purchased by selling pre-funded warrant (in shares)	0.1
Price per share (in dollars per share)	$ 1.7024
Common stock, par value (in dollars per share)	0.0001
Warrant exercise price (in dollars per share)	$ 1.69
Expiration period	7 years
Proceeds from issuance of stock	$ 35
December 2021 Private Placement | Pre-Funded Warrant
Class of Stock [Line Items]
Shares purchased by selling pre-funded warrant (in shares)	1
November 2020 Underwritten Offering
Class of Stock [Line Items]
Shares issuable per warrants (in shares)		3,109,378
Warrants to purchase aggregate shares of common stock (in shares)		4,149,378
Shares purchased by selling pre-funded warrant (in shares)		1
Common stock, par value (in dollars per share)		$ 0.001
Warrant exercise price (in dollars per share)		$ 6.50
Expiration period		5 years
Proceeds from issuance of stock		$ 25
Common stock, issued (in shares)		1,040,000
November 2020 Underwritten Offering | Minimum
Class of Stock [Line Items]
Price of each share of common stock and accompanying common warrant (in dollars per share)		$ 6.024
November 2020 Underwritten Offering | Maximum
Class of Stock [Line Items]
Price of each share of common stock and accompanying common warrant (in dollars per share)		$ 6.025
Public Offering
Class of Stock [Line Items]
Price per share (in dollars per share)				$ 100
Shares issuable under warrants (in shares)				5,750,000
Public Offering | Series 1 Preferred
Class of Stock [Line Items]
Number of shares of common stock sold in offering (in shares)				575,000
Weighted average exercise price (in dollars per share)				$ 130
Public Offering | Common Stock
Class of Stock [Line Items]
Shares issuable per warrants (in shares)				10
Weighted average exercise price (in dollars per share)				$ 13
Class of warrant or right, notice period for percentage change				61 days
Public Offering | Minimum | Common Stock
Class of Stock [Line Items]
Warrants, limitations on ownership after exercise				9.99%
Public Offering | Maximum | Common Stock
Class of Stock [Line Items]
Warrants, limitations on ownership after exercise				19.99%
Private placement option | Series 2 redeemable convertible non-voting preferred stock
Class of Stock [Line Items]
Price per share (in dollars per share)				$ 100
Number of shares of common stock sold in offering (in shares)				350,000	350,000
Shares issuable under warrants (in shares)				2,800,000
Weighted average exercise price (in dollars per share)				$ 10
Private placement option | Series 3 redeemable convertible non-voting preferred stock
Class of Stock [Line Items]
Number of shares of common stock sold in offering (in shares)				250,000	250,000
Private placement option | Preferred Stock
Class of Stock [Line Items]
Price per share (in dollars per share)				$ 140
Shares issuable under warrants (in shares)				875,000
Weighted average exercise price (in dollars per share)				$ 14

PUBLIC OFFERING AND PRIVATE P_4

PUBLIC OFFERING AND PRIVATE PLACEMENT - Fair Value of Derivative Liability (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Warrant Derivative Liability
Change in fair value	$ 1,637	$ 2,337
Warrant Derivative Liability |  Level 3
Warrant Derivative Liability
Warrants and rights outstanding	2,773
Change in fair value	1,637
Warrants and rights outstanding	$ 4,410

PUBLIC OFFERING AND PRIVATE P_5

PUBLIC OFFERING AND PRIVATE PLACEMENT - Summary of Warrants Outstanding and Exercisable (Details) - $ / shares	Mar. 31, 2022	Dec. 31, 2021
Warrants Outstanding and Exercisable [Abstract]
Warrant Outstanding (in shares)	34,174,260
Warrants Exercisable (in shares)	34,174,260
2019
Warrants Outstanding and Exercisable [Abstract]
Warrant Outstanding (in shares)	5,750,000
Warrants Exercisable (in shares)	5,750,000
Weighted Average Remaining Contractual Life	4 years 4 months 20 days
Weighted Average Exercise Price (in dollars per share)	$ 13
2020
Warrants Outstanding and Exercisable [Abstract]
Warrant Outstanding (in shares)	4,149,378
Warrants Exercisable (in shares)	4,149,378
Weighted Average Remaining Contractual Life	3 years 7 months 2 days
Weighted Average Exercise Price (in dollars per share)	$ 6.50
Issued On November 2, 2020
Warrants Outstanding and Exercisable [Abstract]
Warrant Outstanding (in shares)	1,659,752
Warrants Exercisable (in shares)	1,659,752
Weighted Average Remaining Contractual Life		0 years
Weighted Average Exercise Price (in dollars per share)	$ 0
2021
Warrants Outstanding and Exercisable [Abstract]
Warrant Outstanding (in shares)	2,055,920
Warrants Exercisable (in shares)	2,055,920
Weighted Average Remaining Contractual Life	6 years 8 months 8 days
Weighted Average Exercise Price (in dollars per share)	$ 1.69
Issued On December 7, 2021
Warrants Outstanding and Exercisable [Abstract]
Warrant Outstanding (in shares)	20,559,210
Warrants Exercisable (in shares)	20,559,210
Weighted Average Remaining Contractual Life		0 years
Weighted Average Exercise Price (in dollars per share)	$ 0

REDEEMABLE CONVERTIBLE PREFER_2

REDEEMABLE CONVERTIBLE PREFERRED STOCK (Details) - $ / shares	Aug. 16, 2019	Aug. 31, 2019	Mar. 31, 2022
Class of Stock [Line Items]
Preferred stock, authorized (in shares)		10,000,000
Preferred stock, par value (in dollars per share)		$ 0.01
Series 1 Preferred
Class of Stock [Line Items]
Number of shares of common stock sold in offering (in shares)		1,517,500
Preferred stock, outstanding (in shares)			452,000
Preferred stock, issued (in shares)			452,000
Shares issuable per warrants (in shares)			10
Price per share (in dollars per share)			$ 100
Closing price of common stock (in dollars per share)			$ 25
Common stock redemption requirement, closing price, threshold period			180 days
Common stock redemption, average trading volume period			50 days
50-day trading volume on Nasdaq stock market (in shares)			50,000
Series 2 Preferred Stock
Class of Stock [Line Items]
Preferred stock, outstanding (in shares)			0
Preferred stock, issued (in shares)			0
Series 3 Preferred Stock
Class of Stock [Line Items]
Preferred stock, outstanding (in shares)			0
Preferred stock, issued (in shares)			0
Private placement option | Series 2 Preferred Stock
Class of Stock [Line Items]
Number of shares of common stock sold in offering (in shares)	350,000	350,000
Price per share (in dollars per share)	$ 100
Private placement option | Series 3 Preferred Stock
Class of Stock [Line Items]
Number of shares of common stock sold in offering (in shares)	250,000	250,000

SHARE-BASED COMPENSATION PLAN_2

SHARE-BASED COMPENSATION PLANS - Narrative (Details) $ in Millions	3 Months Ended
	Mar. 31, 2022USD ($)plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation plans | plan	5
Compensation cost not yet recognized | $	$ 2.6
Period for recognition	1 year 3 months 18 days
Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expiration period	10 years
Options | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	2 years
Options | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	4 years

SHARE-BASED COMPENSATION PLAN_3

SHARE-BASED COMPENSATION PLANS - Expense by Classification (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total	$ 599	$ 903
Research and development
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total	294	263
General and administrative
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total	$ 305	$ 640

COMMITMENTS AND CONTINGENCIES (

COMMITMENTS AND CONTINGENCIES (Details) - Licensing Agreements	Dec. 10, 2015USD ($)	Jun. 10, 2015USD ($)product
Agensys, Inc.
Loss Contingencies [Line Items]
Nonrefundable upfront fee	$ 3,000,000
Milestone payments upon first achievement of specified clinical milestones	5,000,000
Milestone payments upon achievement of specified clinical milestones for each licensed product	50,000,000
Milestone payments upon achievement of sales milestones	75,000,000
Option exercise fee	5,000,000
Milestone payments reduced upon exercise of option	$ 65,000,000
Termination period, number of years after first commercial sale of licensed product	10 years
Termination period, notice of failure on uncured items	60 days
Period of notice of failure on uncured items, if material breach is related to failure to make payments	30 days
BioVec Pharma Inc
Loss Contingencies [Line Items]
Nonrefundable upfront fee		$ 100,000
Milestone payments upon first achievement of specified clinical milestones		$ 250,000
Termination period, notice of failure on uncured items		60 days
Upfront fee payment period, number of days from effective date		10 days
License costs due upon first release of product		$ 300,000
License costs due upon first release of product, period of payment		10 days
License agreement, annual fee		$ 150,000
License agreement, annual fee period, from first IND filing		30 days
Milestone payments, number of initial products | product		3
License agreement, milestone payments upon receipt of FDA or EMA registration		$ 2,000,000
Termination notice period for any other breach		90 days
Termination period, after insolvency event		30 days