Alaunos Therapeutics (TCRT) 10-K 30 Mar 22 2021 FY Annual report Financial data

Cover Page

Cover Page - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Mar. 21, 2022	Jun. 30, 2021
Cover [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2021
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	FY
Entity Registrant Name	Alaunos Therapeutics, Inc.
Entity Central Index Key	0001107421
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Trading Symbol	TCRT
Document Transition Report	false
Document Annual Report	true
Security Exchange Name	NASDAQ
Title of 12(b) Security	Common Stock
Entity File Number	001-33038
Entity Incorporation, State or Country Code	DE
Entity Address, Address Line One	8030 El Rio Street
Entity Address, City or Town	Houston
Entity Address, State or Province	TX
Entity Address, Postal Zip Code	77054
Entity Tax Identification Number	84-1475642
City Area Code	346
Local Phone Number	355-4099
Entity Well-known Seasoned Issuer	No
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Interactive Data Current	Yes
Entity Shell Company	false
Entity Small Business	true
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	false
Entity Common Stock, Shares Outstanding		216,127,443
Entity Public Float			$ 543,706,424
Auditor Name	RSM US LLP
Auditor Location	Boston, MA
Auditor Firm ID	49

BALANCE SHEETS

BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 76,054	$ 115,069
Receivables	1,111	4,665
Prepaid expenses and other current assets	1,666	10,855
Total current assets	78,831	130,589
Property and equipment, net	10,941	10,231
Right-of-use asset	4,420	4,650
Deposits	42	130
Other non-current assets	631	745
Total assets	94,865	146,345
Current liabilities:
Accounts payable	1,368	960
Current portion of long-term debt	7,868	0
Accrued expenses	6,076	16,589
Lease liability - current portion	729	819
Total current liabilities	16,041	18,368
Long-term debt	16,250	0
Lease liability - noncurrent portion	4,518	3,995
Total liabilities	36,809	22,363
Commitments and contingencies (Note 9)
Stockholders' equity:
Common stock, $0.001 par value; 350,000,000 shares authorized; 216,127,443 shares issued and outstanding at December 31, 2021 and 250,000,000 shares authorized, 214,591,906 shares issued and outstanding at December 31, 2020	216	215
Additional paid-in capital	900,693	887,868
Accumulated deficit	(842,852)	(764,101)
Total stockholders' equity	58,057	123,982
Total liabilities and stockholders' equity	$ 94,865	$ 146,345

BALANCE SHEETS (Parenthetical)

BALANCE SHEETS (Parenthetical) - $ / shares	Dec. 31, 2021	Dec. 31, 2020
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized	350,000,000	250,000,000
Common stock, shares issued	216,127,443	214,591,906
Common stock, shares outstanding	216,127,443	214,591,906

STATEMENTS OF OPERATIONS

STATEMENTS OF OPERATIONS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Income Statement [Abstract]
Collaboration revenue	$ 398	$ 0
Operating expenses:
Research and development	49,643	52,696
General and administrative	27,564	27,665
Property and equipment and right of use assets impairment	740	0
Total operating expenses	77,947	80,361
Loss from operations	(77,549)	(80,361)
Other income, net	(1,202)	385
Net loss	(78,751)	(79,976)
Net income (loss) applicable to common stockholders	$ (78,751)	$ (79,976)
Basic and diluted net loss per share	$ (0.37)	$ (0.38)
Weighted average common shares outstanding used to compute basic net income (loss) per share	214,399,074	209,636,456

STATEMENTS OF CHANGES IN STOCKH

STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common Stock	Additional Paid In Capital	Accumulated Deficit
Balance at Dec. 31, 2019	$ 95,010	$ 182	$ 778,953	$ (684,125)
Balance (in shares) at Dec. 31, 2019		181,803,320
Stock-based compensation	6,829		6,829
Exercise of employee stock options	$ 442		442
Exercise of employee stock options (in shares)	338,333	252,799
Common stock issuance		2,814,673
Restricted stock awards		$ 1	(1)
Restricted stock awards (in shares)		805,900
Cancelled restricted common stock (in shares)		(194,897)
Issuance of common stock in connection with an at the market offering, net	$ 13,016	$ 3	13,013
Issuance of common stock in connection with an at the market offering, net of commissions and expenses of $400 (Shares)		2,814,673
Stock Issued During Period Shares Issuance Of Common Stock In Connection With Public Offering		29,110,111
Issuance of common stock in connection with a public offering, net of commissions and expenses of $5,900	88,661	$ 29	88,632
Issuance of common stock in connection with a public offering, net of commissions and expenses of $5,900 (in shares)		29,110,111
Net loss	(79,976)			(79,976)
Balance at Dec. 31, 2020	123,982	$ 215	887,868	(764,101)
Balance (in shares) at Dec. 31, 2020		214,591,906
Stock-based compensation	10,774		10,774
Exercise of employee stock options	$ 1,036		1,036
Exercise of employee stock options (in shares)	363,109	363,109
Common stock issuance		5,991
Restricted stock awards		$ 1	(1)
Restricted stock awards (in shares)		1,601,224
Cancelled restricted common stock (in shares)		(434,787)
Issuance of warrants	$ 1,016		1,016
Issuance of common stock in connection with an at the market offering, net of commissions and expenses of $400 (Shares)		5,991
Net loss	(78,751)			(78,751)
Balance at Dec. 31, 2021	$ 58,057	$ 216	$ 900,693	$ (842,852)
Balance (in shares) at Dec. 31, 2021		216,127,443

STATEMENTS OF CHANGES IN STOC_2

STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY (Parenthetical) $ in Thousands	12 Months Ended
	Dec. 31, 2020USD ($)
Market Offering [Member]
Issuance of common stock, commissions and expenses	$ 400
Common Stock Issuance Cost	400
Public Offering [Member]
Issuance of common stock, commissions and expenses	5,900
Common Stock Issuance Cost	$ 5,900

STATEMENTS OF CASH FLOWS

STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Cash flows from operating activities:
Net loss	$ (78,751)	$ (79,976)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation	2,597	1,128
Impairments	740	0
Amortization of financing costs	383	0
Stock-based compensation	10,774	6,829
(Increase) decrease in:
Receivables	3,555	(1,335)
Prepaid expenses and other current assets	(9,189)	(11,566)
Right of use assets	(352)	(2,378)
Other noncurrent assets	201	(635)
Increase (decrease) in:
Accounts payable	274	54
Accrued expenses	(10,512)	5,272
Lease liabilities	434	2,462
Net cash used in operating activities	(61,468)	(57,013)
Cash flows from investing activities:
Purchases of property and equipment	(3,323)	(9,778)
Net cash used in investing activities	(3,323)	(9,778)
Cash flows from financing activities:
Proceeds from Issuance of Long-term Debt	25,000	0
Payment of debt issuance cost	(260)	0
Proceeds from exercise of stock options	1,036	442
Issuance of common stock in connection with a public offering, net	0	88,661
Issuance of common stock in connection with an at the market offering, net	0	13,016
Net cash provided by financing activities	25,776	102,119
Net decrease in cash and cash equivalents, and restricted cash	(39,015)	35,328
Cash and cash equivalents, and restricted cash, beginning of period	115,069	79,741
Cash and cash equivalents, and restricted cash, end of period	76,054	115,069
Supplementary disclosure of cash flow information:
Cash paid for interest	630	0
Amounts included in accrued expenses and accounts payable related to property and equipment	134	471
Supplementary disclosure of noncash investing and financing activities:
Warrants issued with long-term debt	$ 1,016	$ 0

Organization

Organization	12 Months Ended
	Dec. 31, 2021
Accounting Policies [Abstract]
Organization	1. Organization Alaunos Therapeutics, Inc., which is referred to herein as “Alaunos,” or the “Company,” is a clinical-stage oncology-focused cell therapy company developing adoptive TCR therapies, designed to treat multiple solid tumor types in large cancer patient populations with unmet clinical needs. On January 25, 2022, the Company changed its corporate name from Ziopharm Oncology, Inc. to Alaunos Therapeutics, Inc. The Company is leveraging its proprietary, non-viral Sleeping Beauty gene transfer platform and its novel cancer mutation hotspot TCR library to design and manufacture personalized cell therapies that target neoantigens arising from common tumor-related mutations in key oncogenic genes, including KRAS, TP53, and EGFR. The Company’s operations to date have consisted primarily of conducting research and development and raising capital to fund those efforts. In May 2021, the Company announced that it will be winding down its existing Controlled IL-12 clinical program for the treatment of recurrent glioblastoma multiforme. The Company will continue to seek a partner for this program and has also begun exploring potential synergies between this technology and its cell therapy programs. Costs incurred during the year ended December 31, 2021 under the program wind-down have not been material. The Company has operated at a loss since its inception in 2003 and has no recurring revenue from operations. The Company anticipates that losses will continue for the foreseeable future. As of December 31, 2021, the Company had approximately $ 76.1  million of cash and cash equivalents. The Company’s accumulated deficit at December 31, 2021 was approximately $ 842.9  million. Given its current development plans and cash management efforts, the Company anticipates cash resources will be sufficient to fund operations into the second quarter of 2023. The Company’s ability to continue operations after its current cash resources are exhausted depends on its ability to obtain additional financing or to achieve profitable operations, as to which no assurances can be given. Cash requirements may vary materially from those now planned because of changes in the Company’s focus and direction of its research and development programs, competitive and technical advances, patent developments, regulatory changes or other developments. If adequate additional funds are not available when required, or if the Company is unsuccessful in entering into partnership agreements for further development of its product candidates, management may need to curtail its development efforts and planned operations to conserve cash. The Company’s amended and restated certificate of incorporation authorizes it to issue 350,000,000 shares of common stock. As of December 31, 2021, there were 216,127,443 shares of common stock outstanding and an additional 33,620,711 shares of common stock reserved for issuance pursuant to outstanding stock options and warrants.

Financings

Financings	12 Months Ended
	Dec. 31, 2021
Text Block [Abstract]
Financings	2. Financings 2021 Loan and Security Agreement On August 6, 2021, the Company entered into a Loan and Security Agreement with Silicon Valley Bank and affiliates of Silicon Valley Bank (collectively, "SVB") (the "Loan and Security Agreement"). The Loan and Security Agreement provided for an initial term loan of $ 25.0 million funded at the closing ("Term A Tranche"), with an additional tranche of $ 25.0 million available if certain funding and clinical milestones were met by August 31, 2022 ("Term B Tranche"). Effective December 28, 2021, the Company, entered into a First Amendment (the “Amendment”) to the Loan and Security Agreement (the "Amended Loan and Security Agreement"). The Amended Loan and Security Agreement extends the interest-only period through August 31, 2022, and provides for an automatic extension through August 31, 2023, if certain funding and clinical milestones are met by August 31, 2022 (the “Amended Milestones”). The Amendment eliminated the Term B Tranche, which remained unfunded, leaving only the Term A Tranche (the "SVB Facility"). Under the Amended Loan and Security Agreement, the SVB Facility will mature on August 1, 2023; however, if the Company achieves the Amended Milestones on or prior to August 31, 2022, then the maturity will automatically extend to August 1, 2024. Please refer to Note 4, Debt, for further discussion of the Loan and Security Agreement and the Amended Loan and Security Agreement. February 2020 Public Offering On February 5, 2020, the Company issued and sold 27,826,086 shares of its common stock at an offering price to the public of $ 3.25 per share, for aggregate net proceeds of approximately $ 84.8 million after deducting underwriting discounts and offering expenses paid by the Company. The offering was made pursuant to the Company's effective registration statement on Form S-3ASR (File No. 333-232283) previously filed with the Securities and Exchange Commission (the “SEC”) and a prospectus supplement thereunder. On March 10, 2020, the underwriters exercised their option to purchase an additional 1,284,025 shares. The net proceeds were approximately $ 3.9 million after deducting underwriting discounts and offering expenses paid by us. At-the-Market Offering Program In June 2019, the Company entered into an Open Market Sale Agreement (the "Sales Agreement") with Jefferies, pursuant to which the Company may offer and sell, from time to time through Jefferies, shares of its common stock having an aggregate offering price of up to $ 100.0 million. Shares will be sold pursuant to the Company’s effective registration statement on Form S-3ASR (File No. 333-232283), as previously filed with the SEC. There were no sales under the Sales Agreement during the year ended December 31, 2021. D uring the year ended December 31, 2020, the Company issued and sold an aggregate of 2,814,673 shares for aggregate net proceeds of approximately $ 13.0 million after deducting underwriting discounts and offering expenses payable by us.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2021
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	3. Summary of Significant Accounting Policies Basis of Presentation The accompanying financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America, or U.S. GAAP. Use of Estimates The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenue and expenses during the reporting period. Although the Company regularly assesses these estimates, actual results could differ from those estimates. Changes in estimates are recorded in the period in which they become known. The Company’s most significant estimates and judgments used in the preparation of the financial statements are: • Clinical trial expenses and other research and development expenses; • Collaboration agreements; • Fair value measurements of stock-based compensation; and • Income taxes. Impact of COVID-19 Pandemic With the ongoing COVID-19 pandemic, the Company has implemented business continuity plans designed to address and mitigate the impact of the COVID-19 pandemic on its business and operations. The Company continues to evaluate the impact of the COVID-19 global pandemic on patients, healthcare providers and its employees, as well as its operations and the operations of its business partners and healthcare communities. In response to the COVID-19 pandemic, the Company has implemented policies at its locations to mitigate the risk of exposure to COVID-19 by its personnel, including restrictions on the number of staff in any given research and development laboratory and a work-from-home policy applicable to the majority of its personnel. The extent to which the COVID-19 pandemic impacts the Company’s business, clinical development and regulatory efforts and the value of its common stock, will depend on future developments that are highly uncertain and cannot be predicted with confidence at this time, such as the ultimate duration of the pandemic, travel restrictions, quarantines, social distancing and business closure requirements, and the effectiveness of actions taken globally to contain and treat the disease. The global economic slowdown, the overall disruption of global healthcare systems and the other risks and uncertainties associated with the COVID-19 pandemic could have a material adverse effect on the Company’s business, financial condition, results of operations and growth prospects. Subsequent Events The Company evaluated all events and transactions that occurred after the balance sheet date through the date of the Annual Report. The Company did not have any material subsequent events that impacted its financial statements or disclosures. Organizational Changes On February 25, 2021, the Company announced that Heidi Hagen, formerly the Lead Independent Director, was appointed Interim Chief Executive Officer, replacing Laurence Cooper, M.D., Ph.D. Ms. Hagen also remained a member of the board of directors. Dr. Cooper also stepped down from his seat on the board of directors and has continued to support the Company’s research and development, or “R&D,” programs as a consultant. On August 22, 2021, the board of directors appointed Kevin S. Boyle, Sr., as Chief Executive Officer of the Company, effective August 30, 2021. Effective upon Mr. Boyle's employment, Ms. Hagen resigned as the Company's Interim Chief Executive Officer but continued to serve as a member of the board of directors. Ms. Hagen resigned as member of the board of directors effective November 2, 2021. On November 4, 2021, the Company provided written notice of termination of the consulting agreement by and between the Company and Danforth Advisors, LLC, a financial consultancy firm specializing in working with life sciences companies (the “Cunningham Consulting Agreement”). Pursuant to the terms of the Cunningham Consulting Agreement, Tim Cunningham, the Company’s interim Chief Financial Officer and principal financial officer, provided services to the Company. Cash and Cash Equivalents Cash equivalents consist primarily of demand deposit accounts, certificates of deposit and deposits in short-term U.S. treasury money market mutual funds. Cash equivalents are stated at cost, which approximates fair market value. Concentrations of Credit Risk Financial instruments which potentially subject the Company to concentrations of credit risk consist principally of cash and cash equivalents. The Company maintains cash accounts in commercial banks, which may, at times, exceed federally insured limits. The Company has not experienced any losses in such accounts. The Company believes it is not exposed to any significant credit risk on cash and cash equivalents. Property and Equipment Property and equipment are stated at cost, less accumulated depreciation and amortization. Expenditures for maintenance and repairs are charged to expense while the costs of significant improvements are capitalized. Depreciation and amortization is calculated on a straight-line basis using the following periods, which represent the estimated useful lives of the assets: ●  Office and computer equipment  3 years ●  Software  3 years ●  Laboratory equipment  5 years ●  Leasehold improvements  Life of the lease Costs, including certain design, construction and installation costs related to assets that are under construction and are in the process of being readied for their intended use, are recorded as construction in progress and are not depreciated until such time as the subject asset is placed in service. Repairs and maintenance that do not extend the useful life of the asset are expensed as incurred. Upon sale, retirement, or other disposition of these assets, the costs and related accumulated depreciation are removed from the respective accounts and any gain or loss on the disposition is included on its Statements of Operations. Long-Lived Assets Assessments of long-lived assets and the remaining useful lives of such long-lived assets are reviewed for impairment whenever a triggering event occurs or changes in circumstances indicate that the carrying amount of the assets may not be recoverable. An asset, or group of assets, are considered to be impaired when the undiscounted estimated net cash flows expected to be generated by the asset, or group of assets, are less than its carrying amount. The impairment recognized is the amount by which the carrying amount exceeds the fair market value of the impaired asset, or group of assets, based on the present value of the expected future cash flows associated with the use of the asset. Operating Segments Operating segments are identified as components of an enterprise about which separate discrete financial information is available for evaluation by the chief operating decision maker, the Company’s chief operating decision maker, in making decisions regarding resource allocation and assessing performance. The Company views its operations and manages its business in one operating segment and does not track expenses on a program-by-program basis. Warrants The Company assesses whether warrants issued require accounting as derivatives. The Company determined that the warrants were (1) indexed to the Company’s own stock and (2) classified in stockholders’ equity in accordance with Financial Accounting Standards Board (“FASB”) Accounting Standards Codification (“ASC”) Topic 815, Derivatives and Hedging . As such, the Company has concluded the warrants meet the scope exception for determining whether the instruments require accounting as derivatives and should be classified in stockholders’ equity. Fair Value Measurements The Company has certain financial assets and liabilities recorded at fair value which have been classified as Level 1, 2 or 3 within the fair value hierarchy as described in the accounting standards for fair value measurements. • Level 1—Quoted prices in active markets for identical assets or liabilities. • Level 2—Inputs other than Level 1 that are observable, either directly or indirectly, such as quoted prices for similar assets or liabilities; quoted prices in markets that are not active; or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities. • Level 3—Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities. Assets and liabilities measured at fair value on a recurring and nonrecurring basis as of December 31, 2021 and 2020 are as follows: ($ in thousands) Fair Value Measurements at Reporting Date Using Description Balance as of Quoted Prices in Significant Other Significant Cash equivalents $ 75,222 $ 75,222 $ — $ — ($ in thousands) Fair Value Measurements at Reporting Date Using Description Balance as of Quoted Prices in Significant Other Significant Cash equivalents $ 75,990 $ 75,990 $ — $ — The cash equivalents represent demand deposit accounts and deposits in a short-term United States treasury money market mutual fund quoted in an active market and classified as a Level 1 asset. Fair value of non-financial instruments The Company evaluates its assets for impairment whenever events or changes in circumstances indicate that indicators of impairment exist. In those evaluations, the Company compares estimated future undiscounted cash flows generated by each asset (or asset group) to the carrying value of the asset (or asset group) to determine if an impairment charge is required. If the undiscounted cash flows test fails, the Company estimates the fair value of the asset (or asset group) to determine the impairment. During 2021, following the Company's strategic restructuring and further cost reduction initiatives, the Company determined that changes in the intended use of its Boston office represented an indicator of impairment, resulting in an impairment charge of $ 0.6 million to the right-of-use asset. In addition, the Company impaired approximately $ 0.1 million of leasehold improvements and various other assets associated with its decision to close the Company's Boston office. Refer to Note 8 for further details. Revenue Recognition from Collaboration Agreements Revenue for the year ended December 31, 2021 consisted of $0.4 million and for the year ended December 31, 2020 consisted of $ 0 . For the year ended December 31, 2021, the Company recognized revenue through its Collaboration Agreement with Solasia Pharma K.K. due to the achievement of a milestone, as further described in Note 9, Commitments and Contingencies. The Company primarily generates revenue through collaboration arrangements with strategic partners for the development and commercialization of product candidates. The Company recognizes revenue in accordance with ASC 606, Revenue from Contracts with Customers (“ASC 606”). The core principle of ASC 606 is that an entity should recognize revenue to depict the transfer of promised goods and/or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods and/or services. To determine the appropriate amount of revenue to be recognized for arrangements that the Company determines are within the scope of ASC 606, the Company performs the following steps: (i) identify the contract(s) with the customer, (ii) identify the performance obligations in the contract, (iii) determine the transaction price, (iv) allocate the transaction price to the performance obligations in the contract and (v) recognize revenue when (or as) each performance obligation is satisfied. The Company recognizes collaboration revenue under certain of the Company’s license or collaboration agreements that are within the scope of ASC 606. The Company’s contracts with customers typically include promises related to licenses to intellectual property, research and development services and options to purchase additional goods and/or services. If the license to the Company’s intellectual property is determined to be distinct from the other performance obligations identified in the arrangement, the Company recognizes revenue from non-refundable, up-front fees allocated to the license when the license is transferred to the licensee and the licensee is able to use and benefit from the license. For licenses that are bundled with other promises, the Company utilizes judgement to assess the nature of the combined performance obligation to determine whether the combined performance obligation is satisfied over time or at a point in time and, if over time, the appropriate method of measuring progress for purposes of recognizing revenue from non-refundable, up-front fees. Contracts that include an option to acquire additional goods and/or services are evaluated to determine if such option provides a material right to the customer that it would not have received without entering into the contract. If so, the option is accounted for as a separate performance obligation. If not, the option is considered a marketing offer which would be accounted for as a separate contract upon the customer’s election. The terms of the Company’s arrangements with customers typically include the payment of one or more of the following:(i) non-refundable, up-front payment, (ii) development, regulatory and commercial milestone payments, (iii) future options and (iv) royalties on net sales of licensed products. Accordingly, the transaction price is generally comprised of a fixed fee due at contract inception and variable consideration in the form of milestone payments due upon the achievement of specified events and tiered royalties earned when customers recognize net sales of licensed products. The Company measures the transaction price based on the amount of consideration to which it expects to be entitled in exchange for transferring the promised goods and/or services to the customer. The Company utilizes the most likely amount method to estimate the amount of variable consideration, to predict the amount of consideration to which it will be entitled. Amounts of variable consideration are included in the transaction price to the extent that it is probable that a significant reversal in the amount of cumulative revenue recognized will not occur when the uncertainty associated with the variable consideration is subsequently resolved. At the inception of each arrangement that includes development and regulatory milestone payments, the Company evaluates whether the associated event is considered probable of achievement and estimates the amount to be included in the transaction price using the most likely amount method. Milestone payments that are not within the control of the Company or the licensee, such as those dependent upon receipt of regulatory approval, are not considered to be probable of achievement until the triggering event occurs. At the end of each reporting period, the Company reevaluates the probability of achievement of each milestone and any related constraint, and if necessary, adjusts its estimate of the overall transaction price. Any such adjustments are recorded on a cumulative catch-up basis, which would affect revenue and net loss in the period of adjustment. For arrangements that include sales-based royalties, including milestone payments based upon the achievement of a certain level of product sales, the Company recognizes revenue upon the later of: (i) when the related sales occur or (ii) when the performance obligation to which some or all of the payment has been allocated has been satisfied (or partially satisfied). Consideration that would be received for optional goods and/or services is excluded from the transaction price at contract inception. The Company allocates the transaction price to each performance obligation identified in the contract on a relative standalone selling price basis. However, certain components of variable consideration are allocated specifically to one or more particular performance obligations in a contract to the extent both of the following criteria are met: (i) the terms of the payment relate specifically to the efforts to satisfy the performance obligation or transfer the distinct good or service and (ii) allocating the variable amount of consideration entirely to the performance obligation or the distinct good or service is consistent with the allocation objective of the standard whereby the amount allocated depicts the amount of consideration to which the entity expects to be entitled in exchange for transferring the promised goods or services. The Company develops assumptions that require the use of judgment to determine the standalone selling price for each performance obligation identified in each contract. The key assumptions utilized in determining the standalone selling price for each performance obligation may include forecasted revenue, development timelines, estimated research and development costs, discount rates, likelihood of exercise and probabilities of technical and regulatory success. Revenue is recognized based on the amount of the transaction price that is allocated to each respective performance obligation when or as the performance obligation is satisfied by transferring a promised good and/or service to the customer. For performance obligations that are satisfied over time, the Company recognizes revenue by measuring the progress toward complete satisfaction of the performance obligation using a single method of measuring progress which depicts the performance in transferring control of the associated goods and/or services to the customer. The Company uses input methods to measure the progress toward the complete satisfaction of performance obligations satisfied over time. The Company evaluates the measure of progress each reporting period and, if necessary, adjusts the measure of performance and related revenue recognition. Any such adjustments are recorded on a cumulative catch-up basis, which would affect revenue and net loss in the period of adjustment. Research and Development Costs As part of the process of preparing the Company's financial statements, the Company is required to estimate its accrued research and development expenses. This process involves reviewing open contracts and purchase orders, communicating with its personnel to identify services that have been performed on its behalf and estimating the level of service performed and the associated costs incurred for the services when the Company has not yet been invoiced or otherwise notified of the actual costs. The majority of the Company's service providers invoice the Company in arrears for services performed, on a predetermined schedule or when contractual milestones are met; however, a few require advanced payments. The Company makes estimates of its accrued expenses as of each balance sheet date in its financial statements based on facts and circumstances known to it at that time. Examples of estimated accrued research and development expenses include fees paid to: • clinical research organizations, or CROs, in connection with performing research services on its behalf and clinical trials, • investigative sites or other providers in connection with clinical trials, • vendors in connection with preclinical and clinical development activities, and • vendors related to product manufacturing, development, and distribution of preclinical and clinical supplies. The Company bases its expenses related to preclinical studies and clinical trials on its estimates of the services received and efforts expended pursuant to quotes and contracts with multiple CROs that conduct and manage clinical trials on its behalf. The financial terms of these agreements are subject to negotiation, vary from contract to contract and may result in uneven payment flows. There may be instances in which payments made to the Company's vendors will exceed the level of services provided and result in a prepayment of the clinical expense. Payments under some of these contracts depend on factors such as the completion of clinical trial milestones. In accruing service fees, the Company estimates the time period over which services will be performed, enrollment of patients, number of sites activated 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 its estimate, the Company adjusts the accrual or amount of prepaid expense accordingly. Although the Company does not expect its estimates to be materially different from amounts actually incurred, its understanding of the status and timing of services performed relative to the actual status and timing of services performed may vary and may result in it reporting amounts that are too high or too low in any particular period. To date, the Company has not made any material adjustments to its prior estimates of accrued research and development expenses. Income Taxes Income taxes are accounted for under the liability method. Deferred tax assets and liabilities are recognized for the estimated future tax consequences of temporary differences between the financial statement carrying amounts and their respective tax bases. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the year in which the temporary differences are expected to be recovered or settled. The Company evaluates the realizability of its deferred tax assets and establishes a valuation allowance when it is more likely than not that all or a portion of deferred tax assets will not be realized. The Company accounts for uncertain tax positions using a “more-likely-than-not” threshold for recognizing and resolving uncertain tax positions. The evaluation of uncertain tax positions is based on factors including, but not limited to, changes in tax law, the measurement of tax positions taken or expected to be taken in tax returns, the effective settlement of matters subject to audit, new audit activity and changes in facts or circumstances related to a tax position. The Company evaluates this tax position on an annual basis. The Company also accrues for potential interest and penalties, related to unrecognized tax benefits in income tax expense (Note 12). Accounting for Stock-Based Compensation Stock-based compensation cost is measured at the grant date, based on the estimated fair value of the award, and is recognized as expense over the employee’s requisite service period. Stock-based compensation expense is based on the number of awards ultimately expected to vest and is reduced for forfeitures as they occur. Consistent with prior years, the Company uses the Black-Scholes option pricing model which requires estimates of the expected term option holders will retain their options before exercising them and the estimated volatility of the Company’s common stock price over the expected term. The Company recognizes the full impact of its share-based employee payment plans in the statements of operations for each of the years ended December 31, 2021 and 2020 and did not capitalize any such costs on the balance sheets. The Company recognized $ 7.4 million of compensation expense related to stock options for the year ended December 31, 2021 and $ 4.3 million of compensation expense related to stock options for the year ended December 31, 2020. The Company recognized $ 3.4 million of compensation expense, related to restricted stock for the year ended December 31, 2021 and $ 2.5 million for the year ended December 31, 2020 (Note 13). The total compensation expense relating to vesting of stock options and restricted stock awards for the year ended December 31, 2021 was $ 10.8 million and $ 6.8 million for the year ended December 31, 2020. The following table presents share-based compensation expense included in the Company’s Statements of Operations: Year ended December 31, ($ in thousands) 2021 2020 Research and development $ 2,598 $ 2,098 General and administrative 8,176 4,731 Share based employee compensation expense 10,774 6,829 The fair value of each stock option is estimated at the date of grant using the Black-Scholes option pricing model. The estimated weighted-average fair value of stock options granted to employees in 2021 was approximately $ 2.62 per share and was approximately $ 2.15 per share for the year ended December 31, 2020. Assumptions regarding volatility, expected term, dividend yield and risk-free interest rate are required for the Black-Scholes model. The volatility assumption is based on the Company’s historical experience. The risk-free interest rate is based on a U.S. treasury note with a maturity similar to the option award’s expected life. The expected life represents the average period of time that options granted are expected to be outstanding. The Company calculated expected term using the simplified method described in SEC Staff Accounting Bulletin, or SAB, No. 107 and No. 110 as it continues to meet the requirements promulgated in SAB No. 110. The assumptions for volatility, expected life, dividend yield and risk-free interest rate are presented in the table below: 2021 2020 Risk-free interest rate 0.50 - 1.36 % 0.36 - 1.68 % Expected life in years 5.50 - 6.25 5.75 - 6.25 Expected volatility 72.53 - 74.80 % 71.11 - 74.41 % Expected dividend yield - - Net Loss per Share Basic net loss per common share is computed by dividing net loss applicable to common stockholders by the weighted average number of shares of common stock outstanding for the period. Diluted net loss per share is computed using the weighted-average number of shares of common stock outstanding during the period, plus the dilutive effect of outstanding options and warrants, using the treasury stock method and the average market price of the Company’s common stock during the applicable period, unless their effect on net loss per share is antidilutive. The effect of computing diluted net loss per common share was antidilutive for any potentially issuable shares of common stock from the conversion of stock options, unvested restricted stock and warrants and, as such, have been excluded from the calculation. The computation of basic and diluted net loss per share consists of the following: For the Year Ended December 31, 2021 2020 Net loss $ ( 78,751 ) $ ( 79,976 ) Weighted-average common shares outstanding, basic and diluted 214,399,074 209,636,456 Net loss per share, basic and diluted $ ( 0.37 ) $ ( 0.38 ) Certain shares related to some of the Company’s outstanding common stock options, unvested restricted stock and warrants have not been included in the computation of diluted net loss per share for the years ended December 31, 2021 and 2020 as the result would be antidilutive. Such potential common shares on December 31, 2021 and 2020 consist of the following: December 31, 2021 2020 Stock options 10,665,869 6,832,386 Inducement stock options 32,500 588,333 Unvested restricted stock 1,198,580 786,280 Warrants 22,922,342 22,272,727 34,819,291 30,479,726 New Accounting Pronouncements In December 2019, the FASB issued ASU 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes , which is intended to simplify various aspects related to accounting for income taxes. ASU 2019-12 removes certain exceptions to the general principles in ASC 740 and also clarifies and amends existing guidance to improve consistent application. The Company adopted this standard effective January 1, 2021, with no material impact upon adoptio n.

Debt

Debt	12 Months Ended
	Dec. 31, 2021
Debt Disclosure [Abstract]
Debt	Debt The carrying values of the Company's debt obligation were as follows: December 31, ($ in thousands) 2021 Loan and Security Agreement $ 25,209 Unamortized discount on Loan and Security Agreement ( 1,091 ) Total debt 24,118 Less: current portion of long-term debt ( 7,868 ) Long-term debt $ 16,250 On August 6, 2021, the Company entered into a Loan and Security Agreement with SVB, or the Loan and Security Agreement. The Loan and Security Agreement provided for an initial term loan of $ 25.0 million funded at the closing, with an additional tranche of $ 25.0 million available if certain funding and clinical milestones were met by August 31, 2022. On December 28, 2021, the Company entered into a First Amendment, (the “Amendment”) to the Loan and Security Agreement (the “Amended Loan and Security Agreement”). Under the terms of the Amended Loan and Security Agreement, the SVB Facility was modified to eliminate the additional $25.0 million tranche, which remained unfunded, leaving only the initial $25.0 million as the full amount available under the SVB Facility. The SVB Facility bears interest at a floating rate per annum on outstanding loans, payable monthly, at the greater of (a) 7.75 % and (b) the current published U.S. prime rate, plus a margin of 4.5 % . As of December 31, 2021, interest on the outstanding loans was 7.75 %. The Amended Loan and Security Agreement provides for an interest-only period which extends through August 31, 2022 and may be automatically extended through August 31, 2023 if, on or prior to August 31, 2022, SVB receives evidence satisfactory to it, confirming that the Company has (i) received at least $ 50.0 million in net cash proceeds from the sale of the Company’s equity securities after the date of the Amended Loan and Security Agreement, on terms and conditions acceptable to SVB, and (ii) achieved positive data in the first cohort of the Library TCR-T Trial endorsed by an independent safety monitoring committee as a safe dose to proceed (together, the “Amended Milestones”). After the interest-only payment period, aggregate outstanding borrowings are payable in twelve consecutive, equal monthly installments of principal plus accrued interest. All outstanding principal and accrued and unpaid interest under the SVB Facility and all other outstanding obligations under the Amended Loan and Security Agreement are due and payable on August 1, 2023 ; however, if the Company achieves the Amended Milestones on or prior to August 31, 2022, then the maturity will be automatically extended to August 1, 2024 . In addition to the payment of the outstanding principal plus accrued interest due, the Company will also owe SVB 5.75 % of the original principal amounts borrowed as a final payment. We are permitted to make up to two prepayments, subject to the prepayment premium, of the SVB Facility, each payment of at least $ 5.0 million. Such prepayment premium would be 3.00 % of the principal amount of the SVB Facility if prepaid prior to the first anniversary of the effective date, 2.00 % of the principal amount of the SVB Facility if prepaid on or after the first anniversary of the effective date but prior to the second anniversary of the effective date and 1.00 % of the principal amount of the SVB Facility if prepaid on or after the second anniversary of the effective date but prior to the maturity date. No amount that has been repaid may be reborrowed. The Loan and Security Agreement required the Company to cash collateralize half of the sum of the outstanding principal amount of the term loans, plus an amount equal to 5.75 % of the original principal amount of any portion of the SVB Facility actually extended, if the Company failed to achieve certain fundraising milestones on or prior to December 31, 2021. The Amended Loan and Security Agreement revised the Company's cash collateralization obligation to require the Company to cash collateralize half of the sum of only the then-outstanding principal amount of the SVB Facility, plus an amount equal to 5.75 % of the original principal amount of the SVB Facility if the Company does not achieve the Amended Milestones on or prior to August 31, 2022. In the event a cash collateralization were to occur, so long as no event of default has occurred and, after subtracting the eighth scheduled payment of principal and interest on the SVB Facility, the sum of the aggregate of outstanding principal and accrued and unpaid interest, plus the final payment, is equal to or less than $ 9,770,933 , then, within ten business days of the date of receipt of the eighth scheduled payment of principal and interest on the SVB Facility, SVB will release $ 2.5 million from the collateral account, so long as the balance in the collateral account after the release would equal or exceed $ 10.0 million. If no event of default has occurred and, after subtracting the tenth scheduled payment of principal and interest on the SVB Facility, the sum of the aggregate of outstanding principal and accrued and unpaid interest, plus the final payment, is equal to or less than $ 5,604,167 , then, within ten business days of the date of receipt of the tenth scheduled payment of principal and interest on the SVB Facility, SVB will release a further $ 4.0 million from the collateral account, so long as the balance in the collateral account after the release would equal or exceed $ 6.0 million. The SVB Facility and related obligations under the Amended Loan and Security Agreement are secured by substantially all of the Company’s properties, rights and assets, except for its intellectual property (which is subject to a negative pledge under the Amended Loan and Security Agreement). In addition, the Amended Loan and Security Agreement contains customary representations, warranties, events of default and covenants. In connection with its entry into the Loan and Security Agreement, the Company issued to SVB warrants to purchase (i) up to 432,844 shares of the Company’s common stock, par value $ 0.001 per share in the aggregate, and (ii) up to an additional 432,842 shares of common stock, in the aggregate, in the event the Company achieves certain clinical milestones, in each case at an exercise price per share of $ 2.22 . In connection with the entry into the Amendment, the Company amended and restated the warrants issued to SVB. As amended and restated, the warrants are for up to 649,615 shares of the Company's common stock, in the aggregate, at an exercise price per share of $ 1.16 , or the SVB Warrants. The SVB Warrants expire on August 6, 2031 . The issuance costs for the Loan and Security Agreement, including the Amended Loan and Security Agreement, were approximately $ 1.2 million and primarily related to the warrants issued to SVB, which will be amortized into interest expense over the period to August 1, 2023 . Interest expense, including the amortization of issuance costs, was $ 1.2 million for the year ended December 31, 2021. The fair value of the Amended Loan and Security Agreement as of December 31, 2021 approximates its face value due to proximity to the transaction.

Property and Equipment, net

Property and Equipment, net	12 Months Ended
	Dec. 31, 2021
Property, Plant and Equipment [Abstract]
Property and Equipment, net	5. Property and Equipment, net Property and equipment, net, consists of the following: December 31, ($ in thousands) 2021 2020 Office and computer equipment $ 2,534 $ 869 Software 1,236 1,153 Leasehold improvements 9,474 7,457 Laboratory equipment 5,110 5,401 Construction-in-progress — 313 18,354 15,193 Less: accumulated depreciation ( 7,413 ) ( 4,962 ) Property and equipment, net $ 10,941 $ 10,231 Depreciation expense charged to the statement of operations for the year ended December 31, 2021 was $ 2.6 million and was $ 1.1 million for the year ended December 31, 2020. During the year ended December 31, 2021, the Company impaired property and equipment by $ 0.1 million. Refer to Note 3, Summary of Significant Accounting Policies , for further details.

Accrued Expenses

Accrued Expenses	12 Months Ended
	Dec. 31, 2021
Payables and Accruals [Abstract]
Accrued Expenses	6. Accrued Expenses Accrued expenses consist of the following: ($ in thousands) 2021 2020 Clinical $ 1,677 $ 4,450 Employee compensation 1,695 3,298 Professional services 825 3,993 Preclinical services 363 749 Manufacturing services 1,056 3,159 Accrued vacation 227 725 Payroll taxes and benefits — 16 Other consulting services 66 199 Other 167 — $ 6,076 $ 16,589

Related Party Transactions

Related Party Transactions	12 Months Ended
	Dec. 31, 2021
Related Party Transactions [Abstract]
Related Party Transactions	7. Related Party Transactions Collaboration with PGEN and MD Anderson On January 13, 2015, the Company, together with Precigen, entered into the MD Anderson License with MD Anderson (which Precigen subsequently assigned to PGEN). Pursuant to the MD Anderson License, the company, together with PGEN, hold an exclusive, worldwide license to certain technologies owned and licensed by MD Anderson including technologies relating to novel CAR T-cell therapies, non-viral gene transfer systems, genetic modification and/or propagation of immune cells and other cellular therapy approaches, Natural Killer, or NK Cells, and TCRs, arising from the laboratory of Laurence Cooper, M.D., Ph.D., who served as the Company’s Chief Executive Officer from May 2015 to February 2021 and was formerly a tenured professor of pediatrics at MD Anderson. In partial consideration for entering into the MD Anderson License, the Company issued MD Anderson an aggregate of 11,722,163 shares of common stock for which the Company incurred a $ 67.3 million charge recorded in 2015. 0.1 million to MD Anderson compared to $ 0 during the year ended December 31, 2020. The net balance of cash resources on hand at MD Anderson available to offset expenses and future costs for the year ended December 31, 2021 was $ 0 and for the year ended December 31, 2020 was $ 8.1 million, which is included in other current assets on the Company’s balance sheet. Collaboration with Vineti Inc. On July 9, 2020, the Company entered into a master service agreement and statement of work with Vineti, Inc., ("Vineti"). Pursuant to the agreements, Vineti is developing a software platform to coordinate and orchestrate the order, cell collection and manufacturing process for the Company’s T-cell therapy, or TCR-T, clinical programs. Heidi Hagen, who became a director of the Company in June 2019 and resigned November 2, 2021 and the Company's Interim Chief Executive Officer on February 25, 2021 and resigned on August 30, 2021, is a co-founder and former officer, of Vineti. During the year ended December 31, 2021, the Company recorded expenses of approximately $ 0.4 million and during the year ended December 31, 2020, the Company recorded expenses of approximately $ 29,000 , for services performed by Vineti. WaterMill Settlement Agreement On February 4, 2021, the Company entered into an agreement, or the Settlement Agreement, with WaterMill Asset Management Corp. and Robert W. Postma (collectively, the "WaterMill Parties"). Pursuant to the Settlement Agreement, the Company increased the size of its board of directors from eight to nine directors and appointed Mr. Postma to fill the newly created directorship. In accordance with the Settlement Agreement, we agreed to reimburse the WaterMill Parties for up to $400,000 of their reasonable out-of-pocket expenses out of a total of approximately $ 650,000 in fees and expenses actually incurred by the WaterMill Parties in connection with (i) the WaterMill Parties' solicitation of written consents from our stockholders to vote in favor of certain proposals, as set forth in the definitive consent statement filed by the WaterMill Parties on October 30, 2020, and (ii) the negotiation, execution, and effectuation of the Settlement Agreement. As of February 19, 2021, we have fully reimbursed the WaterMill Parties an aggregate amount of $ 400,000 . Joint Venture with TriArm Therapeutics/Eden BioCell On December 18, 2018, the Company and TriArm Therapeutics, Ltd. (“TriArm”) launched Eden BioCell, Ltd. (“Eden BioCell”) as a joint venture to lead commercialization of the Company’s Sleeping Beauty -generated CAR-T therapies in the People’s Republic of China (including Macau and Hong Kong), Taiwan and Korea. The Company licensed to Eden BioCell the rights in Greater China for its third-generation Sleeping Beauty -generated CAR-T therapies targeting the CD19 antigen. Eden BioCell is owned equally by the Company and TriArm and the parties share decision-making authority. TriArm has contributed $ 10.0 million to Eden BioCell and has committed up to an additional $ 25.0 million to this joint venture. TriArm also manages all clinical development in the territory pursuant to a Master Services Agreement between TriArm and Eden BioCell. James Huang, who became a director of the Company in July 2020, Chairman of the board of directors in January 2021, and Executive Chairman in February 2021, was the founder and serves as managing partner of Panacea Venture, which is an investor in TriArm. Mr. Huang also serves as a member of Eden BioCell’s board of directors. For the years ended December 31, 2021 and 2020, Eden BioCell incurred a net loss and the Company continues to have no commitment to fund its operations. In September 2021, TriArm and Alaunos mutually agreed to dissolve the Eden BioCell joint venture. Refer to Note 15, Joint Venture , for further details.

Leases

Leases	12 Months Ended
	Dec. 31, 2021
Leases, Operating [Abstract]
Leases	8. Leases Operating Leases In June 2012, the Company entered into a master lease for the Company’s office in Boston, Massachusetts, which was originally set to expire in August 2016 , but renewed through August 31, 2021. On April 22, 2021, the Company extended its lease for a portion of office space currently held at the Company's office space in Boston. The renewal of the portion of the Company's office space was originally set to expire on August 31, 2021, but has now been extended through August 31, 2026 . As of December 31, 2021, and December 31, 2020, a total security deposit of $ 0.1 million is included in deposits on the Company’s balance sheet. In December 2021, the Company made the decision to move its operations away from its former corporate office in Boston. As described in Note 3, Summary of Significant Accounting Policies, the Company's change in the intended use of the Boston office represented an indicator of impairment. We determined the aggregate carrying value of the asset group (approximately $ 1.4 million) was in excess of the aggregate estimated fair value and recorded an impairment charge of $ 0.6 million to the right-of-use asset and approximately $ 0.1 million to associated property and equipment. The fair value was determined based on the amount and timing of estimated net future cash flows, discounted at a risk-adjusted rate of 10 %. The Boston office has been fully vacated as of December 31, 2021. On January 30, 2018, the Company entered into a lease agreement for office space in Houston, Texas at MD Anderson. Under the terms of the Houston lease agreement, the Company leased approximately 210 square feet and was required to make rental payments at an average monthly rate of approximately $ 1,000 . This lease was terminated effective March 31, 2020. On March 12, 2019, the Company entered into a lease agreement for office and lab space in Houston, Texas at MD Anderson through April 2021 . Under the terms of the lease agreement, the Company leases approximately 1,038 square feet and was required to make rental payments at an average monthly rate of approximately $ 2,000 through April 2021. On October 15, 2019, the Company entered into a lease agreement for additional office and laboratory space in Houston through February 2027 . Under the terms of the lease, the Company leases from MD Anderson, approximately 8,443 square feet and is initially required to make rental payments of approximately $ 17,000 per month through February 2027, subject to an annual base rent increase of approximately 3.0 % throughout the term. Effective April 7, 2020, the Company leased an additional 5,594 square feet from MD Anderson. The Company is initially required to make rental payments of approximately $ 12,000 per month through February 2027 , subject to an annual base rent increase of approximately 3.0 % throughout the term. On December 15, 2020, we entered into a second agreement with MD Anderson to lease additional space on MD Anderson’s campus (the “2020 Lease”). As of December 31, 2021, the Company has approximately 32,148 square feet under lease from MD Anderson. The Company is initially required to make rental payments of approximately $ 37,000 per month through April 2028, subject to an annual base rent increase of approximately 3.0 % throughout the term beginning in April 2023. The 2020 Lease may be extended for one additional five-year term at our election. The components of lease expense were as follows: Year Ended December 31, ($ in thousands) 2021 2020 Operating lease cost $ 1,394 $ 1,054 Total lease cost $ 1,394 $ 1,054 Weighted-average remaining lease term (years) 5.58 6.19 Weighted-average discount rate 8.00 % 8.00 % Cash paid for amounts included in the measurement of the lease liabilities were $ 1.3 million for the year-ended December 31, 2021. The Company recognized new operating lease assets obtained in exchange for operating lease liabilities of $ 1.4 million for the year-ended December 31, 2021. As of December 31, 2021, the maturities of the Company’s operating lease liabilities were as follows (in thousands): Maturity of Lease Liabilities Operating Leases 2022 1,102 2023 1,132 2024 1,166 2025 1,201 2026 1,121 Thereafter 752 Total lease payments 6,474 Less: imputed interest ( 1,227 ) Present value of lease payments $ 5,247

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2021
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	9. Commitments and Contingencies License Agreements Exclusive License Agreement with PGEN Therapeutics On October 5, 2018, the Company entered into an exclusive license agreement, or License Agreement, with PGEN Therapeutics, or PGEN, a wholly owned subsidiary of Precigen Inc., or Precigen, which was formerly known as Intrexon Corporation. As between the Company and PGEN, the terms of the License Agreement replaced and superseded the terms of: (a) that certain Exclusive Channel Partner Agreement by and between the Company and Precigen, dated January 6, 2011, as amended by the First Amendment to Exclusive Channel Partner Agreement effective September 13, 2011, the Second Amendment to the Exclusive Channel Partner Agreement effective March 27, 2015, and the Third Amendment to Exclusive Channel Partner Agreement effective June 29, 2016, which was subsequently assigned by Precigen to PGEN; (b) certain rights and obligations pursuant to that certain License and Collaboration Agreement effective March 27, 2015 between the Company, Precigen and ARES TRADING S.A., or Ares Trading, a subsidiary of Merck KGaA, or Merck, as assigned by Precigen to PGEN, or the Ares Trading Agreement; (c) that certain License Agreement between the Company, Precigen, and MD Anderson, with an effective date of January 13, 2015, or the MD Anderson License, which was subsequently assigned by Precigen and assumed by PGEN effective as of January 1, 2018; and (d) that certain research and development agreement between the Company, Precigen and MD Anderson with an effective date of August 17, 2015, or the 2015 R&D Agreement, and any amendments or statements of work thereto. Pursuant to the terms of the License Agreement, the Company has exclusive, worldwide rights to research, develop and commercialize (i) TCR products designed for neoantigens for the treatment of cancer, (ii) products utilizing Precigen’s RheoSwitch® gene switch, or RTS, for the treatment of cancer, referred to as IL-12 Products and (iii) CAR products directed to (A) CD19 for the treatment of cancer, referred to as CD19 Products, and (B) BCMA for the treatment of cancer, subject to certain obligations to pursue such target under the Ares Trading Agreement. Under the License Agreement, the Company also has exclusive, worldwide rights for certain patents relating to the Sleeping Beauty technology to research, develop and commercialize TCR products for both neoantigens and shared antigens for the treatment of cancer, referred to as TCR Products. The Company is solely responsible for all aspects of the research, development and commercialization of the exclusively licensed products for the treatment of cancer. The Company is required to use commercially reasonable efforts, as defined in the License Agreement, to develop and commercialize IL-12 products, CD19 products and TCR Products. In consideration of the licenses and other rights granted by PGEN, the Company will pay PGEN an annual license fee of $ 100,000 and the Company has agreed to reimburse PGEN for certain historical costs of the licensed programs up to $ 1.0 million, which was fully paid during the year ended December 31, 2019. The Company will make milestone payments totaling up to an additional $ 52.5 million for each exclusively licensed program upon the initiation of later stage clinical trials and upon the approval of exclusively licensed products in various jurisdictions. In addition, the Company will pay PGEN tiered royalties ranging from low-single digit to high-single digit on the net sales derived from the sales of any approved IL-12 products and CAR products. The Company will also pay PGEN royalties ranging from low-single digit to mid-single digit on the net sales derived from the sales of any approved TCR products, up to a maximum royalty amount of $ 100.0 million in the aggregate. The Company will also pay PGEN twenty percent of any sublicensing income received by us relating to the licensed products. The Company is responsible for all development costs associated with each of the licensed products. PGEN will pay the Company royalties ranging from low-single digits to mid-single digits on the net sales derived from the sale of PGEN’s CAR products, up to a maximum royalty amount of $ 100.0 million. In consideration of the Company's entry into the License Agreement, Precigen has forfeited and returned to the Company all shares of the Company's Series 1 preferred stock held by or payable to Precigen. The transaction represented a capital transaction between related parties and the date of settlement was accounted for during the License Agreement year ended December 31, 2018. In October 2020, the Company entered into an amendment to the License Agreement relating to the transfer of certain materials and PGEN’s obligations to provide transition assistance relating to the IL-12 products. License Agreement and 2015 Research and Development Agreement —The University of Texas MD Anderson Cancer Center On January 13, 2015, the Company, together with Precigen, entered into the MD Anderson License with MD Anderson (which Precigen subsequently assigned to PGEN). Pursuant to the MD Anderson License, the Company, together with PGEN, holds an exclusive, worldwide license to certain technologies owned and licensed by MD Anderson including technologies relating to novel CAR T-cell therapies, non-viral gene transfer systems, genetic modification and/or propagation of immune cells and other cellular therapy approaches, Natural Killer, or NK Cells, and TCRs, arising from the laboratory of Laurence Cooper, M.D., Ph.D., who served as the Company’s Chief Executive Officer from May 2015 until February 2021 and was formerly a tenured professor of pediatrics at MD Anderson. On August 17, 2015, the Company, Precigen and MD Anderson entered into the 2015 R&D Agreement, to formalize the scope and process for the transfer by MD Anderson, pursuant to the terms of the MD Anderson License, of certain existing research programs and related technology rights, as well as the terms and conditions for future collaborative research and development of new and ongoing research programs. The rights and obligations of Precigen under the 2015 R&D Agreement were assigned to the Company pursuant to the Fourth Amendment to 2015 R&D Agreement which was entered into on September 19, 2019 (the “Fourth Amendment”) with an effective date of October 5, 2018. The activities under the 2015 R&D Agreement are directed by a joint steering committee comprised of two members from the Company and one member from MD Anderson. As provided under the MD Anderson License, the Company provided funding for research and development activities in support of the research programs under the 2015 R&D Agreement for a period of three years and in an amount of no less than $ 15.0 million and no greater than $ 20.0 million per year. On November 14, 2017, the Company entered into an amendment to the 2015 R&D Agreement, extending its term until April 15, 2021 and on October 22, 2019, the Company entered into another amendment to the 2015 R&D Agreement, extending its term until December 31, 2026. During the year ended December 31, 2021, the Company made payments of $ 0.1 million to MD Anderson compared to $ 0 during the year ended December 31, 2020. The net balance of cash resources on hand at MD Anderson available to offset expenses and future costs for the year ended December 31, 2021 was $ 0 and for the year ended December 31, 2020 was $ 8.1 million, which is included in other current assets on the Company’s balance sheet. For the year ended December 31, 2021, we recognized $ 8.1 million in expenses related to the 2015 R&D Agreement and for the year ended December 31, 2020, we recognized $ 12.2 million in expenses related to the 2015 R&D Agreement. The term of the MD Anderson License expires on the last to occur of (a) the expiration of all patents licensed thereunder, or (b) the twentieth anniversary of the date of the MD Anderson License; provided, however, that following the expiration of the term of the MD Anderson License, the Company, together with Precigen, shall then have a fully-paid up, royalty free, perpetual, irrevocable and sublicensable license to use the licensed intellectual property thereunder. After ten years from the date of the MD Anderson License and subject to a 90-day cure period, MD Anderson will have the right to convert the MD Anderson License into a non-exclusive license if the Company and Precigen are not using commercially reasonable efforts to commercialize the licensed intellectual property on a case-by-case basis. After five years from the date of the MD Anderson License and subject to a 180-day cure period, MD Anderson will have the right to terminate the MD Anderson License with respect to specific technology(ies) funded by the government or subject to a third-party contract if the Company and Precigen are not meeting the diligence requirements in such funding agreement or contract, as applicable. MD Anderson may also terminate the agreement with written notice upon material breach by the Company and Precigen, if such breach has not been cured within 60 days of receiving such notice. In addition, the MD Anderson License will terminate upon the occurrence of certain insolvency events for both the Company and Precigen and may be terminated by the mutual written agreement of the Company, PGEN, and MD Anderson. In connection with the execution of the 2019 R&D Agreement described below, on October 22, 2019, the Company amended the 2015 R&D Agreement to extend the term of the 2015 R&D Agreement until December 31, 2026 and to allow cash resources on hand at MD Anderson under the 2015 R&D Agreement to be used for development costs under the 2019 R&D Agreement. 2019 Research and Development Agreement—The University of Texas MD Anderson Cancer Center On October 22, 2019, we entered into the 2019 Research and Development Agreement, or the 2019 R&D Agreement, with MD Anderson, pursuant to which the parties agreed to collaborate with respect to the TCR program. Under the 2019 R&D Agreement, the parties will, among other things, collaborate on programs to expand our TCR library and conduct clinical trials. The activities under the 2019 R&D Agreement are directed by a joint steering committee comprised of two members from our company and one member from MD Anderson. We will own all inventions and intellectual property developed under the 2019 R&D Agreement and we will retain all rights to intellectual property for oncology products manufactured using non-viral gene transfer technologies under the 2019 R&D Agreement, including our Sleeping Beauty technology. We have granted MD Anderson an exclusive license for such intellectual property outside the field of oncology and to develop and commercialize TCR products manufactured using viral gene transfer technologies, and a non-exclusive license for TCR products manufactured using viral-based technologies. Under the 2019 R&D Agreement, we agreed, beginning on January 1, 2021, to reimburse MD Anderson up to a total of $ 20 million for development costs under the 2019 R&D Agreement, after the funds from the 2015 R&D Agreement are exhausted. In addition, we will pay MD Anderson royalties on net sales of its TCR products at rates in the low single digits. We are required to make performance-based payments upon the successful completion of clinical and regulatory benchmarks relating to its TCR products. The aggregate potential benchmark payments are $ 36.5 million, of which only $ 3.0 million will be due prior to the first marketing approval of our TCR products. The royalty rates and benchmark payments owed to MD Anderson may be reduced upon the occurrence of certain events. We also agreed to sell our TCR products to MD Anderson at preferential prices and will sell our TCR products in Texas exclusively to MD Anderson for a limited period of time following the first commercial sale of our TCR products. For the year ended December 31, 2021, the Company incurred expenses of $ 0.5 million related to this agreement compared to $ 0 for the year ended December 31, 2020. The 2019 R&D Agreement will terminate on December 31, 2026 and either party may terminate the 2019 R&D Agreement following written notice of a material breach. The 2019 R&D Agreement also contains customary provisions related to indemnification obligations, confidentiality and other matters. In connection with the execution of the 2019 R&D Agreement, on October 22, 2019, the Company issued MD Anderson a warrant to purchase 3,333,333 shares of the Company's common stock, which is referred to as the MD Anderson Warrant. The MD Anderson Warrant has an initial exercise price of $ 0.00 1 per share, expires on December 31, 2026 , and vests upon the occurrence of certain clinical milestones. As of December 31, 2021, none of the milestones have been met. The MD Anderson Warrant and the shares of the Company's common stock to be issued upon exercise of the MD Anderson Warrant have not been registered under the Securities Act of 1933, as amended, and may not be offered or sold in the United States absent registration or an applicable exemption from registration requirements. License Agreement with the NCI On May 28, 2019, we entered into a patent license agreement, or the Patent License, with the National Cancer Institute, or NCI. Pursuant to the Patent License, we hold an exclusive, worldwide license to certain intellectual property to develop and commercialize patient-derived (autologous), peripheral blood T-cell therapy products engineered by transposon-mediated gene transfer to express TCRs reactive to mutated KRAS, TP53 and EGFR neoantigens. In addition, pursuant to the Patent License, we hold an exclusive, worldwide license to certain intellectual property for manufacturing technologies to develop and commercialize autologous, peripheral blood T-cell therapy products engineered by non-viral gene transfer to express TCRs, as well as a non-exclusive, worldwide license to certain additional manufacturing technologies. On May 29, 2019, January 8, 2020, September 28, 2020, April 16, 2021, May 4, 2021, and August 13, 2021 we amended the Patent License to expand our TCR library to include additional TCRs reactive to mutated KRAS and TP53 neoantigens licensed from the NCI. Pursuant to the terms of the Patent License, we are required to pay the NCI a cash payment in the aggregate amount of $ 1.5 million payable in $ 0.5 million installments within sixty days, six-months, and the twelve-month anniversary of the effective date of the agreement for the Patent License. We also reimbursed the NCI for past patent expenses in the aggregate amount of approximately $ 46,000 . Under the amendment to the patent license signed in January 2020, we agreed to pay the NCI a cash payment of $ 600,000 within sixty days of the amendment and under the amendment to the patent license signed in September 2020, we agreed to pay the NCI a cash payment of $ 411,000 within sixty days of the amendment. The terms of the Patent License also require us to pay the NCI minimum annual royalties in the amount of $ 0.3 million, which amount will be reduced to $ 0.1 million once the aggregate minimum annual royalties paid by us equals $ 1.5 million. We are also required to make performance-based payments upon successful completion of clinical and regulatory benchmarks relating to the licensed products. Of such payments, the aggregate potential benchmark payments are $ 4.3 million, of which aggregate payments of $ 3.0 million are due only after marketing approval in the United States or in Europe, Japan, Australia, China or India. The first benchmark payment of $ 0.1 million will be due upon the initiation of our first sponsored Phase 1 clinical trial of a licensed product or licensed process in the field of use licensed under the Patent License . In addition, we are required to pay the NCI one-time benchmark payments following aggregate net sales of licensed products at certain aggregate net sales ranging from $ 250.0 million to $ 1.0 billion. The aggregate potential amount of these benchmark payments is $ 12.0 million. We must also pay the NCI royalties on net sales of products covered by the Patent License at rates in the low to mid-single digits depending upon the technology included in a licensed product. To the extent we enter into a sublicensing agreement relating to a licensed product, we are required to pay the NCI a percentage of all consideration received from a sublicensee, which percentage will decrease based on the stage of development of the licensed product at the time of the sublicense. The Patent License will expire upon expiration of the last patent contained in the licensed patent rights, unless terminated earlier. The NCI may terminate or modify the Patent License in the event of a material breach, including if we do not meet certain milestones by certain dates, or upon certain insolvency events that remain uncured following the date that is 90 days following written notice of such breach or insolvency event. We may terminate the Patent License, or any portion thereof, in our sole discretion at any time upon 60 days’ written notice to the NCI. In addition, the NCI has the right to: (i) require us to sublicense the rights to the product candidates covered by the Patent License upon certain conditions, including if we are not reasonably satisfying required health and safety needs and (ii) terminate or modify the Patent License, including if we are not satisfying requirements for public use as specified by federal regulations. For the year ended December 31, 2021 we expensed and made payments of $ 0.5 million and for the year ended December 31, 2020 we expensed and made payments of $ 1.5 million. Cooperative Research and Development Agreement (CRADA) with the NCI On January 9, 2017, we entered into a Cooperative Research and Development Agreement (the “CRADA”) with the NCI. The purpose of this collaboration was to advance a personalized TCR-T approach for the treatment of solid tumors. Using our Sleeping Beauty technology, NCI would analyze a patient’s own cancer cells, identify their unique neoantigens and TCRs reactive against those neoantigens and then use our Sleeping Beauty technology to transpose one or more TCRs into T cells for re-infusion. Research conducted under the CRADA will be at the direction of Steven A. Rosenberg, M.D., Ph.D., Chief of the Surgery Branch at the NCI, in collaboration with our researchers and PGEN researchers. We are responsible for providing NCI with the test materials necessary for them to conduct their studies, and eventually, clinical trials pursuant to the CRADA. Inventions, data and materials discovered or produced in connection with performance of the research plan under the CRADA will remain the sole property of the party who produced the discovery. The parties will jointly own all inventions jointly discovered under the research plan. The owner of any invention under the CRADA will make the decision to file a patent covering the invention, or in the case of a jointly owned invention, we will have the first opportunity to file a patent covering the invention. If we fail to provide timely notice of our decision to NCI or decide not to file a patent covering the joint invention, NCI has the right to make the filing. For any invention solely owned by NCI or jointly made by NCI and us for which a patent application was filed, the U.S. Public Health service grants us an exclusive option to elect an exclusive or non-exclusive commercialization license. For inventions owned solely by NCI or jointly owned by NCI and us, which are licensed according to the terms described above, we agreed to grant to the U.S. government a non-exclusive, non-transferable, irrevocable and paid up license to practice the invention or have the invention practiced on its behalf throughout the world. We are also required to grant the U.S. government a non-exclusive, non-transferable, irrevocable and paid up license to practice the invention or have the invention practiced on its behalf throughout the world for any of our solely owned inventions. The agreement may be terminated by any of the parties upon 60 days prior written consent. The NCI has a cleared IND that would permit them to begin this trial. To our knowledge, the trial has not yet enrolled due to matters internal to the NCI and unrelated to our technology. The progress and timeline for this trial, including the timeline for dosing patients, are under control of the NCI. In February 2019, we extended the CRADA with the NCI until January 9, 2022, committing an additional $ 5.0 million to this program. During the year ended December 31, 2021 we made payments of $ 1.25 million and during the year ended December 31, 2020 we made payments of $ 2.5 million, pursuant to the CRADA. For the third and fourth quarters of 2021, we were not required to make payments towards the program as agreed with the NCI. In March 2022, we entered into an amendment to the CRADA that is retroactive, effective January 9, 2022 to extend the term of the CRADA until January 9, 2023. Patent and Technology License Agreement—The University of Texas MD Anderson Cancer Center and the Texas A&M University System On August 24, 2004, the Company entered into a patent and technology license agreement with MD Anderson and the Texas A&M University System, which the Company refers to, collectively, as the Licensors. Under this agreement, the Company was granted an exclusive, worldwide license to rights (including rights to U.S. and foreign patent and patent applications and related improvements and know-how) for the manufacture and commercialization of two classes of organic arsenicals (water- and lipid-based) for human and animal use. The class of water-based organic arsenicals includes darinaparsin. Under the terms of the agreement, the Company may be required to make additional payments to the Licensors upon achievement of certain other milestones in varying amounts which, on a cumulative basis could total up to an additional $ 4.5 million. In addition, the Licensors are entitled to receive single digit percentage royalty payments on sales from a licensed product and will also be entitled to receive a portion of any fees that the Company may receive from a possible sublicense under certain circumstances. During the year ended December 31, 2021, the Company paid fees under the terms of the license agreement of $ 0.1 million. No amounts were accrued or paid during the year ended December 31, 2020. Collaboration Agreement with Solasia Pharma K.K. On March 7, 2011, the Company entered into a License and Collaboration Agreement with Solasia Pharma K. K. ("Solasia"), which was amended on July 31, 2014 to include an exclusive worldwide license. Pursuant to the License and Collaboration Agreement, the Company granted Solasia an exclusive license to develop and commercialize darinaparsin in both intravenous and oral forms and related organic arsenic molecules, in all indications for human use. As consideration for the license, the Company is eligible to receive from Solasia development- and sales-based milestones, a royalty on net sales of darinaparsin, once commercialized, and a percentage of any sublicense revenue generated by Solasia. Solasia will be responsible for all costs related to the development, manufacturing and commercialization of darinaparsin. The Company’s Licensors, as defined in the agreement, will receive a portion of all milestone and royalty payments made by Solasia to the Company in accordance with the terms of the license agreement with the Licensors. During the year ended December 31, 2021, the Company recorded $ 0.4 million of collaboration revenue under the collaboration agreement with Solasia in accordance with variable consideration guidance within ASC Topic 606, Revenue from Contracts with Customers . The collaboration revenue for the year ended December 31, 2021 related to a milestone event, which was met by Solasia related to a submission of approval application in Japan. No amounts were recorded or received during the year ended December 31, 2020.

Warrants

Warrants	12 Months Ended
	Dec. 31, 2021
Warrants Disclosure [Abstract]
Warrants	10. Warrants In connection with the Company’s November 2018 private placement which provided net proceeds of approximately $ 47.1 million, the Company issued warrants to purchase an aggregate of 18,939,394 shares of common stock which became exercisable six months after the closing of the private placement (the "November 2018 Warrants"). The November 2018 Warrants had an exercise price of $ 3.01 per share and have a five-year term. The relative fair value of the November 2018 Warrants was estimated at $ 18.4 million using a Black-Scholes model with the following assumptions: expected volatility of 71 %, risk free interest rate of 2.99 %, expected life of five years and no dividends. The Company assessed whether the November 2018 Warrants require accounting as derivatives. The Company determined that the November 2018 Warrants were (1) indexed to the Company’s own stock and (2) classified in stockholders’ equity in accordance with FASB Accounting Standards Codification (“ASC”) Topic 815, Derivatives and Hedging . As such, the Company has concluded the November 2018 Warrants meet the scope exception for determining whether the instruments require accounting as derivatives and should be classified in stockholders’ equity. On July 26, 2019 and September 12, 2019, the Company entered into agreements with existing investors whereby the investors exercised the November 2018 Warrants for an aggregate of 17,803,031 shares of common stock, at an exercise price of $ 3.01 per share. Proceeds from the warrant exercise, after deducting placement agent fees and other related expenses of $ 1.1 million were approximately $ 52.5 million. The Company issued participating investors new warrants to purchase up to 17,803,031 additional shares of common stock (the "2019 Warrants") as consideration for the warrant holders to exercise their November 2018 Warrants. The 2019 Warrants will expire on the fifth anniversary of the initial exercise date and have an exercise price of $ 7.00 . The 2019 Warrants were valued using a Black-Scholes valuation model and resulted in a $ 60.8 million non-cash charge in the Company’s statement of operations in 2019. On October 22, 2019, the Company entered into the 2019 Agreement with MD Anderson. In connection with the execution of the 2019 Agreement, the Company issued MD Anderson a warrant to purchase 3,333,333 shares of common stock (the "MD Anderson Warrant"). The MD Anderson Warrant has an initial exercise price of $ 0.001 per share and grant date fair value of $ 14.5 million. The MD Anderson Warrant expires on December 31, 2026 and vests upon the occurrence of certain clinical milestones. The Company will recognize expense on the MD Anderson Warrant in the same manner as if the Company paid cash for services to be rendered. For the years ended December 31, 2021 and 2020, the Company did not recognize any expense related to the warrant as no work on the clinical milestones has begun. On August 6, 2021, the Company entered into the Loan and Security Agreement with SVB. Refer to Note 4 - Debt . In connection with the Loan and Security Agreement, the Company issued SVB warrants to purchase 432,844 shares of common stock with an exercise price of $ 2.22 per share. The warrants have a ten-year life and are fully vested upon issuance. The fair value of the warrants was estimated at $ 0.8 million using a Black-Scholes model with the following assumptions: expected volatility of 79 %, risk free interest rate of 1.31 %, expected life of ten years and no dividends. On December 28, 2021, the Company entered into the Amendment, as described in Note 4, Debt, where the original warrants issued to SVB were amended and restated. As amended and restated, the warrants are for up to 649,615 shares of common stock, in the aggregate, at an exercise price per share of $ 1.16 . The amended and restated warrants expire on August 6, 2031 and are fully vested upon issuance. Using a Black-Scholes model with an expected volatility of 81 %, risk free interest rate of 1.49 %, expected life of 10 years and no dividends, the Company recorded a $ 0.2 million increase in the fair value of the warrants due to the modification of the warrants.

Restructuring

Restructuring	12 Months Ended
	Dec. 31, 2021
Restructuring and Related Activities [Abstract]
Restructuring	11. Restructuring On September 27, 2021, in order to lower its existing cost structure in connection with the realignment of its business strategy, the Company announced a strategic reduction in force and notified approximately 60 full-time employees of its intention to terminate their services on or, in most cases, before November 30, 2021. Certain of the notified employees had employment agreements that provided for enhanced severance benefits. The severance benefits, apart from certain continuing Company-paid health care benefits for up to twelve months, were paid in 2021. The Company expensed the following costs associated with termination benefit payments resulting from the strategic reduction in force: December 31, ($ in thousands) 2021 Research and development $ 2,368 General and administrative 1,289 Total severance expense $ 3,657

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2021
Income Tax Disclosure [Abstract]
Income Taxes	12. Income Taxes There is no provision for income taxes because the Company has incurred operating losses since inception. The reported amounts of income tax expense for the years ended December 31, 2021 and 2020 differ from the amounts that would result from applying domestic federal statutory tax rates to pretax losses primarily because of the changes in the valuation allowance. Significant components of the Company’s deferred tax assets at December 31, 2021 and 2020 are as follows: December 31, (in thousands) 2021 2020 Deferred tax assets: Net operating loss carryforwards $ 164,486 $ 147,004 Start-up and organizational costs 21,705 25,909 Research and development credit carryforwards 39,817 37,183 Stock compensation 706 1,478 Capitalized acquisition costs 2,946 3,691 Lease liability 1,278 1,225 Depreciation 102 71 Other 156 135 231,196 216,696 Less valuation allowance ( 230,119 ) ( 215,513 ) Total deferred tax assets 1,077 1,183 Right-of-use asset ( 1,077 ) ( 1,183 ) Total deferred tax liabilities $ ( 1,077 ) $ ( 1,183 ) Net deferred taxes $ — $ — Deferred income taxes reflect the net tax effects of temporary differences between the carrying amount of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes. At December 31, 2021, the Company has aggregate net operating loss carryforwards for federal tax purposes of approximately $ 639 million, of which approximately $ 342 million expires at various dates through December 31, 2037 and approximately $ 297 million can be carried forward indefinitely. The Company also has approximately $ 480 million of state net operating loss carryforwards available to offset future state taxable income, expiring at various dates through 2041. Additionally, the Company has approximately $ 40 million of federal and state research and development credits at December 31, 2021, expiring in varying amounts through 2041 , which may be available to reduce future taxes. The Company has provided a valuation allowance for the full amount of these net deferred tax assets since it is more likely than not that these future benefits will not be realized. However, these deferred tax assets may be available to offset future income tax liabilities and expenses. The valuation allowance increased by $ 14.6 million in 2021 due primarily to net operating loss carryforwards and the increase in research and development credits. Income taxes using the federal statutory income tax rate differ from the Company’s effective tax rate primarily due to non-deductible expenses related to the Company’s issuance of warrants along with the change in the valuation allowance on deferred tax assets. A reconciliation of income tax expense (benefit) at the statutory federal income tax rate and income taxes as reflected in the financial statements is as follows: Year Ended December 31, (in thousands) 2021 2020 Federal income tax at statutory rates 21 % 21 % State income tax, net of federal tax benefit 1 % 3 % Research and development credits 2 % 3 % Stock compensation - 1 % - 1 % Sec. 162(m) - 2 % 0 % Federal/state rate change - 2 % - 2 % Change in valuation allowance - 19 % - 24 % Effective tax rate 0 % 0 % The Company adopted ASC 740, Accounting for Uncertain Tax Positions on January 1, 2007 (“ASC 740”). ASC 740 clarifies the accounting for uncertainty in income taxes recognized in an enterprise’s financial statements in accordance with FASB Statement No. 109, “Accounting for Income Taxes.” ASC 740 prescribes a recognition threshold and measurement of a tax position taken or expected to be taken in a tax return. The Company did not establish any additional reserves for uncertain tax liabilities upon adoption of ASC 740. There were no adjustments to its uncertain tax positions in the years ended December 31, 2021 and 2020. The Company has not recognized any interest and penalties in the statement of operations because of the Company’s net operating losses and tax credits that are available to be carried forward. When necessary, the Company will account for interest and penalties related to uncertain tax positions as part of its provision for federal and state income taxes. The Company does not expect the amounts of unrecognized benefits will change significantly within the next twelve months. The Company is currently open to audit under the statute of limitations by the Internal Revenue Service and state jurisdictions for the years ended December 31, 1999 through 2021. On March 27, 2020, the United States enacted the Coronavirus Aid, Relief, and Economic Security (“CARES”) Act into law which was an emergency economic stimulus package in response to the COVID-19 pandemic and its impact on the economy, public health, state and local governments, individuals and businesses. The Company has considered the legislation surrounding the impact of the CARES Act and the potential effects it may have on the Company. Some of the more significant provisions under the CARES Act include five-year carryback of net operating losses (Section 2303), Refundable AMT credit (Section 2305), relaxation of the limitation of adjusted taxable income (ATI) as determined under IRC Section 163(j) from 30 % to 50 % (Section 2306), and changes to qualified bonus improvement property (QIP) tax life and bonus depreciation eligibility allowing for a 15 -year tax useful life an eligibility for 100 % bonus depreciation (Section 2307). Due to the Company’s history of US taxable losses, and use of MACRS and/or straight-line depreciation for tax purposes, there is no impact to the tax provision as a result of the enactment of the CARES Act. As of December 31, 2020, the Company has analyzed the provisions of the CARES Act and has recorded no income tax benefit or expense related to it.

Stock Option Plan

Stock Option Plan	12 Months Ended
	Dec. 31, 2021
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock Option Plan	13. Stock Option Plan The Company adopted the 2012 Equity Incentive Plan (the “2012 Plan”) in May 2012. Including subsequent increases, the Company had reserved 14,000,000 shares for issuance. On December 31, 2021, there are 2,847,190 shares reserved for issuance and no shares available for future grant. The Company adopted the 2020 Equity Incentive Plan (the “2020 Plan”) in June 2020. The Company reserved 21,000,000 shares for issuance plus a carryover of 1,066,275 shares from the 2012 Plan for a total of 22,066,275 shares. In addition, returning shares from the 2012 Plan are available for issuance under the 2020 Plan. As of December 31, 2021, 5,750,000 shares were registered, 7,818,679 shares reserved for issuance and 30,564 shares available for future grant. As of December 31, 2021 the Company had outstanding options to its employees to purchase up to 9,208,236 shares of the Company’s common stock, to its directors to purchase up to 1,397,633 shares of the Company’s common stock, as well as options to consultants in connection with services rendered to purchase up to 60,000 shares of the Company’s common stock. Stock options to employees generally vest ratably in either quarterly or annual installments over three or four years, commencing on the first anniversary of the grant date and have contractual terms of ten years. Stock options to directors generally vest ratably over one or two years and have contractual terms of ten years. Stock options are valued using the Black-Scholes option pricing model and compensation is recognized based on such fair value over the period of vesting on a straight-line basis. Proceeds from the option exercises during the year ended December 31, 2021 amounted to $ 1.0 million and during the year ended December 31, 2020 amounted to $ 0.4 million. The intrinsic value of these options amounted to $ 0.8 million for the year ended December 31, 2021 and $ 0.3 million for the year ended December 31, 2020. Stock option activity under the Company's stock options plans for the years ending December 31, 2021 and 2020 were as follows: (in thousands, except share and per share data) Number of Shares Weighted- Weighted- Aggregate Outstanding, December 31, 2019 5,842,879 3.21 Granted 2,222,368 3.39 Exercised ( 338,333 ) 2.01 Cancelled ( 886,195 ) 4.22 Outstanding, December 31, 2020 6,840,719 3.81 Granted 9,380,438 2.62 Exercised ( 363,109 ) 2.86 Cancelled ( 5,192,179 ) 3.65 Outstanding, December 31, 2021 10,665,869 $ 2.87 8.67 $ — Options exercisable, December 31, 2021 4,410,312 $ 3.85 7.53 $ — Options exercisable, December 31, 2020 3,596,315 $ 4.17 6.90 $ 598 Options available for future grant at December 31, 2021 30,564 The Company granted 400,000 inducement stock options on July 22, 2019 with exercise prices of $ 5.60 , 65,000 on August 19, 2019 with exercise prices of $ 5.18 , and 65,000 on November 21, 2019 with exercise prices of $ 4.59 . The options vest ratably, over four years, commencing with one quarter on the first anniversary of the grant date and then quarterly thereafter. The options have a contractual term of ten years. These options were granted outside of the 2012 Plan and therefore, are not included in the table above. The grant date fair values were $ 1.5 million for the July 22, 2019 options, $ 231,000 for the August 19, 2019 options, and $ 193,000 for the November 21, 2019 options. As of December 31, 2021, 32,500 options are outstanding from all inducement stock options. On December 31, 2021, total unrecognized compensation costs related to non-vested stock options outstanding amounted to $ 8.1 million. The cost is expected to be recognized over a weighted-average period of 2.1 years. Restricted Stock For the year ended December 31, 2021 the Company issued 1,601,224 shares of restricted stock and 805,900 in the year ended December 31, 2020 to employees and directors. A summary of the status of restricted stock as of December 31, 2021 and 2020 is as follows: Number of Shares Weighted-Average Non-vested, December 31, 2019 939,636 2.93 Granted 805,900 3.75 Vested ( 764,359 ) 3.51 Cancelled ( 194,897 ) 3.44 Non-vested, December 31, 2020 786,280 3.08 Granted 1,601,224 2.60 Vested ( 754,137 ) 3.40 Cancelled ( 434,787 ) 3.45 Non-vested, December 31, 2021 1,198,580 $ 2.10 As of December 31, 2021, there was $ 2.1 million of total unrecognized stock-based compensation expense related to non-vested restricted stock arrangements. The expense is expected to be recognized over a weighted-average period of 2.15 years.

Employee Benefit Plan

Employee Benefit Plan	12 Months Ended
	Dec. 31, 2021
Postemployment Benefits [Abstract]
Employee Benefit Plan	14. Employee Benefit Plan The Company sponsors a qualified 401(k) retirement plan under which employees are allowed to contribute certain percentages of their pay, up to the maximum allowed under Section 401(k) of the IRC, or the 401(k) Plan. The Company may make contributions to the 401(k) Plan at its discretion. The Company contributed approximately $ 0.7 million to the 401(k) Plan during the year ended December 31, 2021 and $ 0.5 million during the year ended December 31, 2020.

Joint Venture

Joint Venture	12 Months Ended
	Dec. 31, 2021
Equity Method Investments and Joint Ventures [Abstract]
Joint Venture	15. Joint Venture On December 18, 2018, the Company entered into a Framework Agreement with TriArm whereby the parties will launch Eden BioCell, to lead clinical development and commercialization of certain Sleeping Beauty -generated CAR-T therapies as set forth in a separate license agreement. On January 3, 2019, Eden BioCell was incorporated in Hong Kong as a private company. Eden BioCell, the Company and TriArm entered into a Share Subscription Agreement on January 23, 2019, where the Company and TriArm agreed to contribute certain intellectual property, services and cash (only with respect to TriArm) to Eden BioCell to subscribe for a certain number of newly issued ordinary shares in the share capital of Eden BioCell. On the closing date, upon the issuance and subscription of the shares, in respect of the aforementioned consideration, 10,000,000 ordinary shares were issued to the Company and 10,000,000 ordinary shares were issued to TriArm. The closing of the transaction occurred on July 5, 2019. The Framework Agreement and Share Subscription Agreements were each respectively amended to be effective as of this date. Upon consummation of the joint venture, Eden BioCell and the Company also entered into a license agreement, pursuant to which the Company licensed the rights to Eden BioCell for third generation Sleeping Beauty -generated CAR-T therapies targeting the CD19 antigen for the territory of China (including Macau and Hong Kong), Taiwan and Korea. Eden BioCell will be responsible for certain milestone and royalty payments to related to the Company’s license agreements with MD Anderson and PGEN. TriArm entered into a Master Services Agreement with Eden BioCell and contributed $ 10.0 million of cash on the closing date. TriArm also committed to contribute an additional $ 25.0 million to Eden BioCell over time through the achievement of specified milestones. TriArm and the Company each received a 50 % equity interest in the joint venture in exchange for their contributions to Eden BioCell. As of July 5, 2019, as a result of the design and purpose of Eden BioCell, the Company determined that Eden BioCell was considered a variable interest entity, or VIE, and concluded that it is not the primary beneficiary of the VIE as it did not have the power to direct the activities of the VIE that most significantly impact its performance. Rather, the Company accounts for the equity interest in Eden BioCell under the equity method of accounting as it has the ability to exercise significant influence over the operations of Eden BioCell. The Company determined that Eden BioCell was not a customer, and therefore, accounted for the transaction as the transfer of nonfinancial assets to be recognized at their fair value on the contribution date. The fair value of the intellectual property contributed to Eden BioCell had a de minimis value due to the early stage of the technology and the likelihood of clinical success. Due to the de minimis fair value of the intellectual property contributed, the Company did not record a gain or loss on this transaction and recognized no value for its equity-method investment. In March 2021, Eden BioCell began treating patients in a clinical trial with the Company’s investigational CD19 RPM CAR-T cell therapy, under the IND cleared by the Taiwan FDA in December. Two patients have now been treated in this trial. The lead investigator at National Taiwan University in Taipei, has reported no serious adverse safety events in either of these patients. Laboratory results continue to support, as previously published, that non-viral Sleeping Beauty gene transfer is effective in genetically modifying autologous T-cells. Patients were infused two days after gene transfer, thus shortening the turnaround time and demonstrating an advantage over viral methods. Based on laboratory data from the first two patients generated between March and May 2021, the TriArm/Eden team concluded, in concert with the investigator and the Company, that further process development work is required. In September 2021, TriArm and the Company mutually agreed to dissolve the joint venture. For the years ended December 31, 2021 and 2020, Eden BioCell incurred a net loss. The Company continues to have no commitment to fund its operations.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2021
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America, or U.S. GAAP.
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenue and expenses during the reporting period. Although the Company regularly assesses these estimates, actual results could differ from those estimates. Changes in estimates are recorded in the period in which they become known. The Company’s most significant estimates and judgments used in the preparation of the financial statements are: • Clinical trial expenses and other research and development expenses; • Collaboration agreements; • Fair value measurements of stock-based compensation; and • Income taxes.
Impact of COVID-19 Pandemic	Impact of COVID-19 Pandemic With the ongoing COVID-19 pandemic, the Company has implemented business continuity plans designed to address and mitigate the impact of the COVID-19 pandemic on its business and operations. The Company continues to evaluate the impact of the COVID-19 global pandemic on patients, healthcare providers and its employees, as well as its operations and the operations of its business partners and healthcare communities. In response to the COVID-19 pandemic, the Company has implemented policies at its locations to mitigate the risk of exposure to COVID-19 by its personnel, including restrictions on the number of staff in any given research and development laboratory and a work-from-home policy applicable to the majority of its personnel. The extent to which the COVID-19 pandemic impacts the Company’s business, clinical development and regulatory efforts and the value of its common stock, will depend on future developments that are highly uncertain and cannot be predicted with confidence at this time, such as the ultimate duration of the pandemic, travel restrictions, quarantines, social distancing and business closure requirements, and the effectiveness of actions taken globally to contain and treat the disease. The global economic slowdown, the overall disruption of global healthcare systems and the other risks and uncertainties associated with the COVID-19 pandemic could have a material adverse effect on the Company’s business, financial condition, results of operations and growth prospects.
Subsequent Events	Subsequent Events The Company evaluated all events and transactions that occurred after the balance sheet date through the date of the Annual Report. The Company did not have any material subsequent events that impacted its financial statements or disclosures.
Organizational Changes	Organizational Changes On February 25, 2021, the Company announced that Heidi Hagen, formerly the Lead Independent Director, was appointed Interim Chief Executive Officer, replacing Laurence Cooper, M.D., Ph.D. Ms. Hagen also remained a member of the board of directors. Dr. Cooper also stepped down from his seat on the board of directors and has continued to support the Company’s research and development, or “R&D,” programs as a consultant. On August 22, 2021, the board of directors appointed Kevin S. Boyle, Sr., as Chief Executive Officer of the Company, effective August 30, 2021. Effective upon Mr. Boyle's employment, Ms. Hagen resigned as the Company's Interim Chief Executive Officer but continued to serve as a member of the board of directors. Ms. Hagen resigned as member of the board of directors effective November 2, 2021. On November 4, 2021, the Company provided written notice of termination of the consulting agreement by and between the Company and Danforth Advisors, LLC, a financial consultancy firm specializing in working with life sciences companies (the “Cunningham Consulting Agreement”). Pursuant to the terms of the Cunningham Consulting Agreement, Tim Cunningham, the Company’s interim Chief Financial Officer and principal financial officer, provided services to the Company.
Cash and Cash Equivalents	Cash and Cash Equivalents Cash equivalents consist primarily of demand deposit accounts, certificates of deposit and deposits in short-term U.S. treasury money market mutual funds. Cash equivalents are stated at cost, which approximates fair market value.
Concentrations of Credit Risk	Concentrations of Credit Risk Financial instruments which potentially subject the Company to concentrations of credit risk consist principally of cash and cash equivalents. The Company maintains cash accounts in commercial banks, which may, at times, exceed federally insured limits. The Company has not experienced any losses in such accounts. The Company believes it is not exposed to any significant credit risk on cash and cash equivalents.
Property and Equipment	Property and Equipment Property and equipment are stated at cost, less accumulated depreciation and amortization. Expenditures for maintenance and repairs are charged to expense while the costs of significant improvements are capitalized. Depreciation and amortization is calculated on a straight-line basis using the following periods, which represent the estimated useful lives of the assets: ●  Office and computer equipment  3 years ●  Software  3 years ●  Laboratory equipment  5 years ●  Leasehold improvements  Life of the lease Costs, including certain design, construction and installation costs related to assets that are under construction and are in the process of being readied for their intended use, are recorded as construction in progress and are not depreciated until such time as the subject asset is placed in service. Repairs and maintenance that do not extend the useful life of the asset are expensed as incurred. Upon sale, retirement, or other disposition of these assets, the costs and related accumulated depreciation are removed from the respective accounts and any gain or loss on the disposition is included on its Statements of Operations.
Long-Lived Assets	Long-Lived Assets Assessments of long-lived assets and the remaining useful lives of such long-lived assets are reviewed for impairment whenever a triggering event occurs or changes in circumstances indicate that the carrying amount of the assets may not be recoverable. An asset, or group of assets, are considered to be impaired when the undiscounted estimated net cash flows expected to be generated by the asset, or group of assets, are less than its carrying amount. The impairment recognized is the amount by which the carrying amount exceeds the fair market value of the impaired asset, or group of assets, based on the present value of the expected future cash flows associated with the use of the asset.
Operating Segments	Operating Segments Operating segments are identified as components of an enterprise about which separate discrete financial information is available for evaluation by the chief operating decision maker, the Company’s chief operating decision maker, in making decisions regarding resource allocation and assessing performance. The Company views its operations and manages its business in one operating segment and does not track expenses on a program-by-program basis.
Warrants	Warrants The Company assesses whether warrants issued require accounting as derivatives. The Company determined that the warrants were (1) indexed to the Company’s own stock and (2) classified in stockholders’ equity in accordance with Financial Accounting Standards Board (“FASB”) Accounting Standards Codification (“ASC”) Topic 815, Derivatives and Hedging . As such, the Company has concluded the warrants meet the scope exception for determining whether the instruments require accounting as derivatives and should be classified in stockholders’ equity.
Fair Value Measurements	Fair Value Measurements The Company has certain financial assets and liabilities recorded at fair value which have been classified as Level 1, 2 or 3 within the fair value hierarchy as described in the accounting standards for fair value measurements. • Level 1—Quoted prices in active markets for identical assets or liabilities. • Level 2—Inputs other than Level 1 that are observable, either directly or indirectly, such as quoted prices for similar assets or liabilities; quoted prices in markets that are not active; or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities. • Level 3—Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities. Assets and liabilities measured at fair value on a recurring and nonrecurring basis as of December 31, 2021 and 2020 are as follows: ($ in thousands) Fair Value Measurements at Reporting Date Using Description Balance as of Quoted Prices in Significant Other Significant Cash equivalents $ 75,222 $ 75,222 $ — $ — ($ in thousands) Fair Value Measurements at Reporting Date Using Description Balance as of Quoted Prices in Significant Other Significant Cash equivalents $ 75,990 $ 75,990 $ — $ — The cash equivalents represent demand deposit accounts and deposits in a short-term United States treasury money market mutual fund quoted in an active market and classified as a Level 1 asset. Fair value of non-financial instruments The Company evaluates its assets for impairment whenever events or changes in circumstances indicate that indicators of impairment exist. In those evaluations, the Company compares estimated future undiscounted cash flows generated by each asset (or asset group) to the carrying value of the asset (or asset group) to determine if an impairment charge is required. If the undiscounted cash flows test fails, the Company estimates the fair value of the asset (or asset group) to determine the impairment. During 2021, following the Company's strategic restructuring and further cost reduction initiatives, the Company determined that changes in the intended use of its Boston office represented an indicator of impairment, resulting in an impairment charge of $ 0.6 million to the right-of-use asset. In addition, the Company impaired approximately $ 0.1 million of leasehold improvements and various other assets associated with its decision to close the Company's Boston office. Refer to Note 8 for further details.
Revenue Recognition from Collaboration Agreements	Revenue Recognition from Collaboration Agreements Revenue for the year ended December 31, 2021 consisted of $0.4 million and for the year ended December 31, 2020 consisted of $ 0 . For the year ended December 31, 2021, the Company recognized revenue through its Collaboration Agreement with Solasia Pharma K.K. due to the achievement of a milestone, as further described in Note 9, Commitments and Contingencies. The Company primarily generates revenue through collaboration arrangements with strategic partners for the development and commercialization of product candidates. The Company recognizes revenue in accordance with ASC 606, Revenue from Contracts with Customers (“ASC 606”). The core principle of ASC 606 is that an entity should recognize revenue to depict the transfer of promised goods and/or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods and/or services. To determine the appropriate amount of revenue to be recognized for arrangements that the Company determines are within the scope of ASC 606, the Company performs the following steps: (i) identify the contract(s) with the customer, (ii) identify the performance obligations in the contract, (iii) determine the transaction price, (iv) allocate the transaction price to the performance obligations in the contract and (v) recognize revenue when (or as) each performance obligation is satisfied. The Company recognizes collaboration revenue under certain of the Company’s license or collaboration agreements that are within the scope of ASC 606. The Company’s contracts with customers typically include promises related to licenses to intellectual property, research and development services and options to purchase additional goods and/or services. If the license to the Company’s intellectual property is determined to be distinct from the other performance obligations identified in the arrangement, the Company recognizes revenue from non-refundable, up-front fees allocated to the license when the license is transferred to the licensee and the licensee is able to use and benefit from the license. For licenses that are bundled with other promises, the Company utilizes judgement to assess the nature of the combined performance obligation to determine whether the combined performance obligation is satisfied over time or at a point in time and, if over time, the appropriate method of measuring progress for purposes of recognizing revenue from non-refundable, up-front fees. Contracts that include an option to acquire additional goods and/or services are evaluated to determine if such option provides a material right to the customer that it would not have received without entering into the contract. If so, the option is accounted for as a separate performance obligation. If not, the option is considered a marketing offer which would be accounted for as a separate contract upon the customer’s election. The terms of the Company’s arrangements with customers typically include the payment of one or more of the following:(i) non-refundable, up-front payment, (ii) development, regulatory and commercial milestone payments, (iii) future options and (iv) royalties on net sales of licensed products. Accordingly, the transaction price is generally comprised of a fixed fee due at contract inception and variable consideration in the form of milestone payments due upon the achievement of specified events and tiered royalties earned when customers recognize net sales of licensed products. The Company measures the transaction price based on the amount of consideration to which it expects to be entitled in exchange for transferring the promised goods and/or services to the customer. The Company utilizes the most likely amount method to estimate the amount of variable consideration, to predict the amount of consideration to which it will be entitled. Amounts of variable consideration are included in the transaction price to the extent that it is probable that a significant reversal in the amount of cumulative revenue recognized will not occur when the uncertainty associated with the variable consideration is subsequently resolved. At the inception of each arrangement that includes development and regulatory milestone payments, the Company evaluates whether the associated event is considered probable of achievement and estimates the amount to be included in the transaction price using the most likely amount method. Milestone payments that are not within the control of the Company or the licensee, such as those dependent upon receipt of regulatory approval, are not considered to be probable of achievement until the triggering event occurs. At the end of each reporting period, the Company reevaluates the probability of achievement of each milestone and any related constraint, and if necessary, adjusts its estimate of the overall transaction price. Any such adjustments are recorded on a cumulative catch-up basis, which would affect revenue and net loss in the period of adjustment. For arrangements that include sales-based royalties, including milestone payments based upon the achievement of a certain level of product sales, the Company recognizes revenue upon the later of: (i) when the related sales occur or (ii) when the performance obligation to which some or all of the payment has been allocated has been satisfied (or partially satisfied). Consideration that would be received for optional goods and/or services is excluded from the transaction price at contract inception. The Company allocates the transaction price to each performance obligation identified in the contract on a relative standalone selling price basis. However, certain components of variable consideration are allocated specifically to one or more particular performance obligations in a contract to the extent both of the following criteria are met: (i) the terms of the payment relate specifically to the efforts to satisfy the performance obligation or transfer the distinct good or service and (ii) allocating the variable amount of consideration entirely to the performance obligation or the distinct good or service is consistent with the allocation objective of the standard whereby the amount allocated depicts the amount of consideration to which the entity expects to be entitled in exchange for transferring the promised goods or services. The Company develops assumptions that require the use of judgment to determine the standalone selling price for each performance obligation identified in each contract. The key assumptions utilized in determining the standalone selling price for each performance obligation may include forecasted revenue, development timelines, estimated research and development costs, discount rates, likelihood of exercise and probabilities of technical and regulatory success. Revenue is recognized based on the amount of the transaction price that is allocated to each respective performance obligation when or as the performance obligation is satisfied by transferring a promised good and/or service to the customer. For performance obligations that are satisfied over time, the Company recognizes revenue by measuring the progress toward complete satisfaction of the performance obligation using a single method of measuring progress which depicts the performance in transferring control of the associated goods and/or services to the customer. The Company uses input methods to measure the progress toward the complete satisfaction of performance obligations satisfied over time. The Company evaluates the measure of progress each reporting period and, if necessary, adjusts the measure of performance and related revenue recognition. Any such adjustments are recorded on a cumulative catch-up basis, which would affect revenue and net loss in the period of adjustment.
Research and Development Costs	Research and Development Costs As part of the process of preparing the Company's financial statements, the Company is required to estimate its accrued research and development expenses. This process involves reviewing open contracts and purchase orders, communicating with its personnel to identify services that have been performed on its behalf and estimating the level of service performed and the associated costs incurred for the services when the Company has not yet been invoiced or otherwise notified of the actual costs. The majority of the Company's service providers invoice the Company in arrears for services performed, on a predetermined schedule or when contractual milestones are met; however, a few require advanced payments. The Company makes estimates of its accrued expenses as of each balance sheet date in its financial statements based on facts and circumstances known to it at that time. Examples of estimated accrued research and development expenses include fees paid to: • clinical research organizations, or CROs, in connection with performing research services on its behalf and clinical trials, • investigative sites or other providers in connection with clinical trials, • vendors in connection with preclinical and clinical development activities, and • vendors related to product manufacturing, development, and distribution of preclinical and clinical supplies. The Company bases its expenses related to preclinical studies and clinical trials on its estimates of the services received and efforts expended pursuant to quotes and contracts with multiple CROs that conduct and manage clinical trials on its behalf. The financial terms of these agreements are subject to negotiation, vary from contract to contract and may result in uneven payment flows. There may be instances in which payments made to the Company's vendors will exceed the level of services provided and result in a prepayment of the clinical expense. Payments under some of these contracts depend on factors such as the completion of clinical trial milestones. In accruing service fees, the Company estimates the time period over which services will be performed, enrollment of patients, number of sites activated 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 its estimate, the Company adjusts the accrual or amount of prepaid expense accordingly. Although the Company does not expect its estimates to be materially different from amounts actually incurred, its understanding of the status and timing of services performed relative to the actual status and timing of services performed may vary and may result in it reporting amounts that are too high or too low in any particular period. To date, the Company has not made any material adjustments to its prior estimates of accrued research and development expenses.
Income Taxes	Income Taxes Income taxes are accounted for under the liability method. Deferred tax assets and liabilities are recognized for the estimated future tax consequences of temporary differences between the financial statement carrying amounts and their respective tax bases. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the year in which the temporary differences are expected to be recovered or settled. The Company evaluates the realizability of its deferred tax assets and establishes a valuation allowance when it is more likely than not that all or a portion of deferred tax assets will not be realized. The Company accounts for uncertain tax positions using a “more-likely-than-not” threshold for recognizing and resolving uncertain tax positions. The evaluation of uncertain tax positions is based on factors including, but not limited to, changes in tax law, the measurement of tax positions taken or expected to be taken in tax returns, the effective settlement of matters subject to audit, new audit activity and changes in facts or circumstances related to a tax position. The Company evaluates this tax position on an annual basis. The Company also accrues for potential interest and penalties, related to unrecognized tax benefits in income tax expense (Note 12).
Accounting for Stock-Based Compensation	Accounting for Stock-Based Compensation Stock-based compensation cost is measured at the grant date, based on the estimated fair value of the award, and is recognized as expense over the employee’s requisite service period. Stock-based compensation expense is based on the number of awards ultimately expected to vest and is reduced for forfeitures as they occur. Consistent with prior years, the Company uses the Black-Scholes option pricing model which requires estimates of the expected term option holders will retain their options before exercising them and the estimated volatility of the Company’s common stock price over the expected term. The Company recognizes the full impact of its share-based employee payment plans in the statements of operations for each of the years ended December 31, 2021 and 2020 and did not capitalize any such costs on the balance sheets. The Company recognized $ 7.4 million of compensation expense related to stock options for the year ended December 31, 2021 and $ 4.3 million of compensation expense related to stock options for the year ended December 31, 2020. The Company recognized $ 3.4 million of compensation expense, related to restricted stock for the year ended December 31, 2021 and $ 2.5 million for the year ended December 31, 2020 (Note 13). The total compensation expense relating to vesting of stock options and restricted stock awards for the year ended December 31, 2021 was $ 10.8 million and $ 6.8 million for the year ended December 31, 2020. The following table presents share-based compensation expense included in the Company’s Statements of Operations: Year ended December 31, ($ in thousands) 2021 2020 Research and development $ 2,598 $ 2,098 General and administrative 8,176 4,731 Share based employee compensation expense 10,774 6,829 The fair value of each stock option is estimated at the date of grant using the Black-Scholes option pricing model. The estimated weighted-average fair value of stock options granted to employees in 2021 was approximately $ 2.62 per share and was approximately $ 2.15 per share for the year ended December 31, 2020. Assumptions regarding volatility, expected term, dividend yield and risk-free interest rate are required for the Black-Scholes model. The volatility assumption is based on the Company’s historical experience. The risk-free interest rate is based on a U.S. treasury note with a maturity similar to the option award’s expected life. The expected life represents the average period of time that options granted are expected to be outstanding. The Company calculated expected term using the simplified method described in SEC Staff Accounting Bulletin, or SAB, No. 107 and No. 110 as it continues to meet the requirements promulgated in SAB No. 110. The assumptions for volatility, expected life, dividend yield and risk-free interest rate are presented in the table below: 2021 2020 Risk-free interest rate 0.50 - 1.36 % 0.36 - 1.68 % Expected life in years 5.50 - 6.25 5.75 - 6.25 Expected volatility 72.53 - 74.80 % 71.11 - 74.41 % Expected dividend yield - -
Net Income (Loss) Per Share	Net Loss per Share Basic net loss per common share is computed by dividing net loss applicable to common stockholders by the weighted average number of shares of common stock outstanding for the period. Diluted net loss per share is computed using the weighted-average number of shares of common stock outstanding during the period, plus the dilutive effect of outstanding options and warrants, using the treasury stock method and the average market price of the Company’s common stock during the applicable period, unless their effect on net loss per share is antidilutive. The effect of computing diluted net loss per common share was antidilutive for any potentially issuable shares of common stock from the conversion of stock options, unvested restricted stock and warrants and, as such, have been excluded from the calculation. The computation of basic and diluted net loss per share consists of the following: For the Year Ended December 31, 2021 2020 Net loss $ ( 78,751 ) $ ( 79,976 ) Weighted-average common shares outstanding, basic and diluted 214,399,074 209,636,456 Net loss per share, basic and diluted $ ( 0.37 ) $ ( 0.38 ) Certain shares related to some of the Company’s outstanding common stock options, unvested restricted stock and warrants have not been included in the computation of diluted net loss per share for the years ended December 31, 2021 and 2020 as the result would be antidilutive. Such potential common shares on December 31, 2021 and 2020 consist of the following: December 31, 2021 2020 Stock options 10,665,869 6,832,386 Inducement stock options 32,500 588,333 Unvested restricted stock 1,198,580 786,280 Warrants 22,922,342 22,272,727 34,819,291 30,479,726
New Accounting Pronouncements	New Accounting Pronouncements In December 2019, the FASB issued ASU 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes , which is intended to simplify various aspects related to accounting for income taxes. ASU 2019-12 removes certain exceptions to the general principles in ASC 740 and also clarifies and amends existing guidance to improve consistent application. The Company adopted this standard effective January 1, 2021, with no material impact upon adoptio n.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2021
Accounting Policies [Abstract]
Assets and Liabilities Measured at Fair Value on Recurring Basis	Assets and liabilities measured at fair value on a recurring and nonrecurring basis as of December 31, 2021 and 2020 are as follows: ($ in thousands) Fair Value Measurements at Reporting Date Using Description Balance as of Quoted Prices in Significant Other Significant Cash equivalents $ 75,222 $ 75,222 $ — $ — ($ in thousands) Fair Value Measurements at Reporting Date Using Description Balance as of Quoted Prices in Significant Other Significant Cash equivalents $ 75,990 $ 75,990 $ — $ —
Share-Based Compensation Expense Included in Statements of Operations	The following table presents share-based compensation expense included in the Company’s Statements of Operations: Year ended December 31, ($ in thousands) 2021 2020 Research and development $ 2,598 $ 2,098 General and administrative 8,176 4,731 Share based employee compensation expense 10,774 6,829
Assumptions for Volatility, Expected life, Dividend Yield and Risk-free Interest Rate	The assumptions for volatility, expected life, dividend yield and risk-free interest rate are presented in the table below: 2021 2020 Risk-free interest rate 0.50 - 1.36 % 0.36 - 1.68 % Expected life in years 5.50 - 6.25 5.75 - 6.25 Expected volatility 72.53 - 74.80 % 71.11 - 74.41 % Expected dividend yield - -
Schedule of Earnings Per Share, Diluted, by Common Class, Including Two Class Method	Basic net loss per common share is computed by dividing net loss applicable to common stockholders by the weighted average number of shares of common stock outstanding for the period. Diluted net loss per share is computed using the weighted-average number of shares of common stock outstanding during the period, plus the dilutive effect of outstanding options and warrants, using the treasury stock method and the average market price of the Company’s common stock during the applicable period, unless their effect on net loss per share is antidilutive. The effect of computing diluted net loss per common share was antidilutive for any potentially issuable shares of common stock from the conversion of stock options, unvested restricted stock and warrants and, as such, have been excluded from the calculation. The computation of basic and diluted net loss per share consists of the following: For the Year Ended December 31, 2021 2020 Net loss $ ( 78,751 ) $ ( 79,976 ) Weighted-average common shares outstanding, basic and diluted 214,399,074 209,636,456 Net loss per share, basic and diluted $ ( 0.37 ) $ ( 0.38 )
Potentially Dilutive Shares Excluded from Computation of Diluted Net Loss Per Share	Such potential common shares on December 31, 2021 and 2020 consist of the following: December 31, 2021 2020 Stock options 10,665,869 6,832,386 Inducement stock options 32,500 588,333 Unvested restricted stock 1,198,580 786,280 Warrants 22,922,342 22,272,727 34,819,291 30,479,726

Debt (Tables)

Debt (Tables)	12 Months Ended
	Dec. 31, 2021
Debt Disclosure [Abstract]
Schedule of Debt	The carrying values of the Company's debt obligation were as follows: December 31, ($ in thousands) 2021 Loan and Security Agreement $ 25,209 Unamortized discount on Loan and Security Agreement ( 1,091 ) Total debt 24,118 Less: current portion of long-term debt ( 7,868 ) Long-term debt $ 16,250

Property and Equipment, net (Ta

Property and Equipment, net (Tables)	12 Months Ended
	Dec. 31, 2021
Property, Plant and Equipment [Abstract]
Component of Property and Equipment, Net	Property and equipment, net, consists of the following: December 31, ($ in thousands) 2021 2020 Office and computer equipment $ 2,534 $ 869 Software 1,236 1,153 Leasehold improvements 9,474 7,457 Laboratory equipment 5,110 5,401 Construction-in-progress — 313 18,354 15,193 Less: accumulated depreciation ( 7,413 ) ( 4,962 ) Property and equipment, net $ 10,941 $ 10,231

Accrued Expenses (Tables)

Accrued Expenses (Tables)	12 Months Ended
	Dec. 31, 2021
Payables and Accruals [Abstract]
Component of Accrued Expenses	Accrued expenses consist of the following: ($ in thousands) 2021 2020 Clinical $ 1,677 $ 4,450 Employee compensation 1,695 3,298 Professional services 825 3,993 Preclinical services 363 749 Manufacturing services 1,056 3,159 Accrued vacation 227 725 Payroll taxes and benefits — 16 Other consulting services 66 199 Other 167 — $ 6,076 $ 16,589

Leases (Tables)

Leases (Tables)	12 Months Ended
	Dec. 31, 2021
Leases, Operating [Abstract]
Components of Lease Expense	The components of lease expense were as follows: Year Ended December 31, ($ in thousands) 2021 2020 Operating lease cost $ 1,394 $ 1,054 Total lease cost $ 1,394 $ 1,054 Weighted-average remaining lease term (years) 5.58 6.19 Weighted-average discount rate 8.00 % 8.00 %
Lessee, Operating Lease, Liability, Maturity	As of December 31, 2021, the maturities of the Company’s operating lease liabilities were as follows (in thousands): Maturity of Lease Liabilities Operating Leases 2022 1,102 2023 1,132 2024 1,166 2025 1,201 2026 1,121 Thereafter 752 Total lease payments 6,474 Less: imputed interest ( 1,227 ) Present value of lease payments $ 5,247

Restructuring (Tables)

Restructuring (Tables)	12 Months Ended
	Dec. 31, 2021
Restructuring and Related Activities [Abstract]
Future termination benefit payments resulting from the strategic reduction in force	The Company expensed the following costs associated with termination benefit payments resulting from the strategic reduction in force: December 31, ($ in thousands) 2021 Research and development $ 2,368 General and administrative 1,289 Total severance expense $ 3,657

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2021
Income Tax Disclosure [Abstract]
Significant Component of Deferred Tax Assets	Significant components of the Company’s deferred tax assets at December 31, 2021 and 2020 are as follows: December 31, (in thousands) 2021 2020 Deferred tax assets: Net operating loss carryforwards $ 164,486 $ 147,004 Start-up and organizational costs 21,705 25,909 Research and development credit carryforwards 39,817 37,183 Stock compensation 706 1,478 Capitalized acquisition costs 2,946 3,691 Lease liability 1,278 1,225 Depreciation 102 71 Other 156 135 231,196 216,696 Less valuation allowance ( 230,119 ) ( 215,513 ) Total deferred tax assets 1,077 1,183 Right-of-use asset ( 1,077 ) ( 1,183 ) Total deferred tax liabilities $ ( 1,077 ) $ ( 1,183 ) Net deferred taxes $ — $ — Deferred income taxes reflect the net tax effects of temporary differences between the carrying amount of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes. At December 31, 2021, the Company has aggregate net operating loss carryforwards for federal tax purposes of approximately $ 639 million, of which approximately $ 342 million expires at various dates through December 31, 2037 and approximately $ 297 million can be carried forward indefinitely. The Company also has approximately $ 480 million of state net operating loss carryforwards available to offset future state taxable income, expiring at various dates through 2041. Additionally, the Company has approximately $ 40 million of federal and state research and development credits at December 31, 2021, expiring in varying amounts through 2041 , which may be available to reduce future taxes. The Company has provided a valuation allowance for the full amount of these net deferred tax assets since it is more likely than not that these future benefits will not be realized. However, these deferred tax assets may be available to offset future income tax liabilities and expenses. The valuation allowance increased by $ 14.6 million in 2021 due primarily to net operating loss carryforwards and the increase in research and development credits. Income taxes using the federal statutory income tax rate differ from the Company’s effective tax rate primarily due to non-deductible expenses related to the Company’s issuance of warrants along with the change in the valuation allowance on deferred tax assets.
Reconciliation of Income Tax Expense (Benefit)	A reconciliation of income tax expense (benefit) at the statutory federal income tax rate and income taxes as reflected in the financial statements is as follows: Year Ended December 31, (in thousands) 2021 2020 Federal income tax at statutory rates 21 % 21 % State income tax, net of federal tax benefit 1 % 3 % Research and development credits 2 % 3 % Stock compensation - 1 % - 1 % Sec. 162(m) - 2 % 0 % Federal/state rate change - 2 % - 2 % Change in valuation allowance - 19 % - 24 % Effective tax rate 0 % 0 % The Company adopted ASC 740, Accounting for Uncertain Tax Positions on January 1, 2007 (“ASC 740”). ASC 740 clarifies the accounting for uncertainty in income taxes recognized in an enterprise’s financial statements in accordance with FASB Statement No. 109, “Accounting for Income Taxes.” ASC 740 prescribes a recognition threshold and measurement of a tax position taken or expected to be taken in a tax return. The Company did not establish any additional reserves for uncertain tax liabilities upon adoption of ASC 740. There were no adjustments to its uncertain tax positions in the years ended December 31, 2021 and 2020. The Company has not recognized any interest and penalties in the statement of operations because of the Company’s net operating losses and tax credits that are available to be carried forward. When necessary, the Company will account for interest and penalties related to uncertain tax positions as part of its provision for federal and state income taxes. The Company does not expect the amounts of unrecognized benefits will change significantly within the next twelve months. The Company is currently open to audit under the statute of limitations by the Internal Revenue Service and state jurisdictions for the years ended December 31, 1999 through 2021. On March 27, 2020, the United States enacted the Coronavirus Aid, Relief, and Economic Security (“CARES”) Act into law which was an emergency economic stimulus package in response to the COVID-19 pandemic and its impact on the economy, public health, state and local governments, individuals and businesses. The Company has considered the legislation surrounding the impact of the CARES Act and the potential effects it may have on the Company. Some of the more significant provisions under the CARES Act include five-year carryback of net operating losses (Section 2303), Refundable AMT credit (Section 2305), relaxation of the limitation of adjusted taxable income (ATI) as determined under IRC Section 163(j) from 30 % to 50 % (Section 2306), and changes to qualified bonus improvement property (QIP) tax life and bonus depreciation eligibility allowing for a 15 -year tax useful life an eligibility for 100 % bonus depreciation (Section 2307). Due to the Company’s history of US taxable losses, and use of MACRS and/or straight-line depreciation for tax purposes, there is no impact to the tax provision as a result of the enactment of the CARES Act. As of December 31, 2020, the Company has analyzed the provisions of the CARES Act and has recorded no income tax benefit or expense related to it.

Stock Option Plans (Tables)

Stock Option Plans (Tables)	12 Months Ended
	Dec. 31, 2021
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock Option Activity Under Stock Option Plan	Stock option activity under the Company's stock options plans for the years ending December 31, 2021 and 2020 were as follows: (in thousands, except share and per share data) Number of Shares Weighted- Weighted- Aggregate Outstanding, December 31, 2019 5,842,879 3.21 Granted 2,222,368 3.39 Exercised ( 338,333 ) 2.01 Cancelled ( 886,195 ) 4.22 Outstanding, December 31, 2020 6,840,719 3.81 Granted 9,380,438 2.62 Exercised ( 363,109 ) 2.86 Cancelled ( 5,192,179 ) 3.65 Outstanding, December 31, 2021 10,665,869 $ 2.87 8.67 $ — Options exercisable, December 31, 2021 4,410,312 $ 3.85 7.53 $ — Options exercisable, December 31, 2020 3,596,315 $ 4.17 6.90 $ 598 Options available for future grant at December 31, 2021 30,564
Summary of Non-Vested Restricted Stock	A summary of the status of restricted stock as of December 31, 2021 and 2020 is as follows: Number of Shares Weighted-Average Non-vested, December 31, 2019 939,636 2.93 Granted 805,900 3.75 Vested ( 764,359 ) 3.51 Cancelled ( 194,897 ) 3.44 Non-vested, December 31, 2020 786,280 3.08 Granted 1,601,224 2.60 Vested ( 754,137 ) 3.40 Cancelled ( 434,787 ) 3.45 Non-vested, December 31, 2021 1,198,580 $ 2.10

Organization - Additional Infor

Organization - Additional Information (Detail) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Cash and cash equivalents	$ 76,054	$ 115,069
Accumulated deficit	$ (842,852)	$ (764,101)
Common stock, shares authorized	350,000,000	250,000,000
Common stock, shares outstanding	216,127,443	214,591,906
Common Stock
Common stock, shares authorized	350,000,000
Common stock, shares outstanding	216,127,443
Common stock reserved for future issuance	33,620,711

Financings - Additional Informa

Financings - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	Mar. 10, 2020	Feb. 05, 2020	Sep. 12, 2019	Nov. 11, 2018	Jun. 30, 2019	Dec. 31, 2021	Dec. 31, 2020	Aug. 06, 2021
Class of Stock [Line Items]
Sale of stock consideration received on transaction						$ 0	$ 88,661
Common stock, par value						$ 0.001	$ 0.001
Issuance of common stock in connection with an at the market offering, net							$ 13,016
Proceeds from private placement			$ 52,500
At The Market Offering [Member]
Class of Stock [Line Items]
Stock issued during period							2,814,673
At The Market Offering [Member] | Maximum [Member]
Class of Stock [Line Items]
Issuance of common stock in connection with an at the market offering, net					$ 100,000
Private Placement [Member]
Class of Stock [Line Items]
Number of securities into which the class of warrant converted			17,803,031	18,939,394
Warrant exercise per share			$ 3.01	$ 3.01
Placement agent fees and other expenses			$ 1,100
Private Placement [Member] | New Warrants [Member]
Class of Stock [Line Items]
Number of securities into which the class of warrant converted			17,803,031
Warrant exercise per share			$ 7
Securities Purchase Agreement [Member]
Class of Stock [Line Items]
Issuance of common stock in connection with an at the market offering, net				$ 47,100
Underwriting Agreement [Member]
Class of Stock [Line Items]
Common stock issuance		27,826,086
Issuance & sale of common stock in public offering price per share		$ 3.25
Sale of stock consideration received on transaction		$ 84,800
Underwriting Agreement [Member] | Stock Option [Member]
Class of Stock [Line Items]
Stock issued during period	1,284,025
Sale of stock consideration received on transaction	$ 3,900
Underwriting Agreement [Member] | At The Market Offering [Member]
Class of Stock [Line Items]
Sale of stock consideration received on transaction							$ 13,000
Silicon Valley Bank [Member] | Term A Tranche
Class of Stock [Line Items]
Loan and Security Agreement								$ 25,000
Silicon Valley Bank [Member] | Term B Tranche
Class of Stock [Line Items]
Additonal tranche facility								$ 25,000

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Summary Of Significant Accounting Policies [Line Items]
Stock based compensation expenses	$ 10,774	$ 6,829
Weighted average fair value of stock option granted	$ 2.62	$ 2.15
Asset Impairment Charges	$ 740	$ 0
Operating Lease Impairment Loss	600
Collaboration revenue	398	0
Accumulated deficit	$ (842,852)	(764,101)
Office and computer equipment
Summary Of Significant Accounting Policies [Line Items]
Property and equipment useful life	3 years
Software
Summary Of Significant Accounting Policies [Line Items]
Property and equipment useful life	3 years
Laboratory equipment
Summary Of Significant Accounting Policies [Line Items]
Property and equipment useful life	5 years
Leasehold improvements
Summary Of Significant Accounting Policies [Line Items]
Asset Impairment Charges	$ 100
Estimated useful life	Life of the lease
Stock Options
Summary Of Significant Accounting Policies [Line Items]
Stock based compensation expenses	$ 7,400	4,300
Restricted Stock
Summary Of Significant Accounting Policies [Line Items]
Stock based compensation expenses	3,400	2,500
Restricted Stock Units (RSUs) [Member]
Summary Of Significant Accounting Policies [Line Items]
Stock based compensation expenses	$ 10,800	$ 6,800

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - Fair Value, Measurements, Recurring - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	$ 75,222	$ 75,990
Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	$ 75,222	$ 75,990

Summary of Significant Accoun_6

Summary of Significant Accounting Policies - Impact of Topic 606 Adoption on Financial Statements (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Accumulated deficit	$ (842,852)	$ (764,101)
Collaboration revenue	398	0
Net loss	(78,751)	(79,976)
Net income (loss) applicable to common shareholders	(78,751)	(79,976)
Net Income (Loss) Attributable to Parent	$ (78,751)	$ (79,976)

Summary of Significant Accoun_7

Summary of Significant Accounting Policies - Stock-Based Compensation Expense Included in Statement of Operations (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation	$ 10,774	$ 6,829
Research and Development
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation	2,598	2,098
General and Administrative
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation	$ 8,176	$ 4,731

Summary of Significant Accoun_8

Summary of Significant Accounting Policies - Fair Value of Stock Options Assumptions Using Black-Scholes Option Valuation Model (Detail)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Risk-free interest rate, Minimum	0.50%	0.36%
Risk-free interest rate, Maximum	1.36%	1.68%
Expected volatility, Minimum	72.53%	71.11%
Expected volatility, Maximum	74.80%	74.41%
Maximum [Member]
Expected life in years	6 years 3 months	6 years 3 months
Minimum [Member]
Expected life in years	5 years 6 months	5 years 9 months

Summary of Significant Accoun_9

Summary of Significant Accounting Policies - Earning Per share Basic and Diluted (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Earnings Per Share, Basic and Diluted [Abstract]
Net loss	$ (78,751)	$ (79,976)
Weighted-average common shares outstanding, basic and diluted	214,399,074	209,636,456
Net loss per share, basic and diluted	$ (0.37)	$ (0.38)

Summary of Significant Accou_10

Summary of Significant Accounting Policies - Potential Dilutive Shares Excluded from Computation of Diluted Net Loss Per Share (Detail) - shares	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount	34,819,291	30,479,726
Warrants
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount	22,922,342	22,272,727
Stock Options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount	10,665,869	6,832,386
Stock Options | Two Thousand Twelve Stock Option Plan [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount	32,500	588,333
Unvested Restricted Stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount	1,198,580	786,280

Debt - Schedule of Debt (Detail

Debt - Schedule of Debt (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Debt Instrument [Line Items]
Total debt	$ 24,118
Less: current portion of long-term debt	(7,868)	$ 0
Long-term debt	16,250	$ 0
Silicon Valley Bank Loan [Member]
Debt Instrument [Line Items]
Loan and Security Agreement	25,209
Unamortized discount on Loan and Security Agreement	$ (1,091)

Debt - Additional Information (

Debt - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	Dec. 28, 2021	Aug. 06, 2021	Aug. 06, 2021	Dec. 31, 2021	Dec. 31, 2020
Line of Credit Facility [Line Items]
Line of credit facility, interest rate		4.50%
Common stock, par value				$ 0.001	$ 0.001
Interest expense amortized date				Aug. 1, 2023
Interest expense				$ 1,200
Term Loan [Member]
Line of Credit Facility [Line Items]
Interest rate				7.75%
Line of credit facility, interest rate		7.75%
Cash proceeds from sale of equity				$ 50,000
Percentage of final payment due		5.75%
Silicon Valley Bank Loan [Member]
Line of Credit Facility [Line Items]
Debt instrument, initial maturity date				Aug. 1, 2023
Debt instrument description of variable rate basis				The SVB Facility bears interest at a floating rate per annum on outstanding loans, payable monthly, at the greater of (a) 7.75% and (b) the current published U.S. prime rate, plus a margin of 4.5%
Debt instrument, extended maturity date				Aug. 1, 2024
Debt instrument, periodic payment				$ 5,000
Description of payment terms				In addition to the payment of the outstanding principal plus accrued interest due, the Company will also owe SVB 5.75% of the original principal amounts borrowed as a final payment. We are permitted to make up to two prepayments, subject to the prepayment premium, of the SVB Facility, each payment of at least $5.0 million. Such prepayment premium would be 3.00% of the principal amount of the SVB Facility if prepaid prior to the first anniversary of the effective date, 2.00% of the principal amount of the SVB Facility if prepaid on or after the first anniversary of the effective date but prior to the second anniversary of the effective date and 1.00% of the principal amount of the SVB Facility if prepaid on or after the second anniversary of the effective date but prior to the maturity date.
Common stock, par value		$ 0.001	$ 0.001
Number of warrants issued		432,844	432,844
Warrant exercise per share		$ 2.22	$ 2.22	$ 1.16
Warrants issued				649,615
Additional number warrants issued		432,842	432,842
Warrants expiration date				Aug. 6, 2031
Silicon Valley Bank Loan [Member] | First anniversary
Line of Credit Facility [Line Items]
Percentage of prepayment premium				0.0300
Silicon Valley Bank Loan [Member] | Second anniversary
Line of Credit Facility [Line Items]
Percentage of prepayment premium				0.0200
Silicon Valley Bank Loan [Member] | Third anniversary
Line of Credit Facility [Line Items]
Percentage of prepayment premium				0.0100
Silicon Valley Bank Loan [Member] | Warrants
Line of Credit Facility [Line Items]
Issuance costs				$ 1,200
Silicon Valley Bank Loan [Member] | Term Loan [Member]
Line of Credit Facility [Line Items]
Initial borrowing		$ 25,000	$ 25,000
Line of Credit Facility, Remaining Borrowing Capacity		25,000	25,000
Proceeds from bank debt			2,500	4,000
Debt instrument balance amount in the collateral account		$ 10,000	$ 10,000	$ 6,000
Silicon Valley Bank Loan [Member] | Term Loan [Member] | Eight Scheduled Payment
Line of Credit Facility [Line Items]
Debt Instrument outstanding principal including accrued and unpaid interest	$ 9,770,933
Silicon Valley Bank Loan [Member] | Term Loan [Member] | Tenth Scheduled Payment
Line of Credit Facility [Line Items]
Debt Instrument outstanding principal including accrued and unpaid interest	$ 5,604,167

Property and Equipment, net - C

Property and Equipment, net - Component of Property and Equipment, Net (Detail) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Property, Plant and Equipment [Line Items]
Property and equipment, Gross	$ 18,354	$ 15,193
Less: accumulated depreciation	(7,413)	(4,962)
Property and equipment, net	10,941	10,231
Office and computer equipment
Property, Plant and Equipment [Line Items]
Property and equipment, Gross	2,534	869
Software
Property, Plant and Equipment [Line Items]
Property and equipment, Gross	1,236	1,153
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property and equipment, Gross	9,474	7,457
Research and development equipment
Property, Plant and Equipment [Line Items]
Property and equipment, Gross	5,110	5,401
Construction-in-process
Property, Plant and Equipment [Line Items]
Property and equipment, Gross	$ 0	$ 313

Property and Equipment, net - A

Property and Equipment, net - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Depreciation	$ 2,597	$ 1,128
Asset Impairment Charges	740	$ 0
Leasehold improvements
Asset Impairment Charges	$ 100

Accrued Expenses - Component of

Accrued Expenses - Component of Accrued Expenses (Detail) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Payables and Accruals [Abstract]
Clinical	$ 1,677	$ 4,450
Employee compensation	1,695	3,298
Professional services	825	3,993
Preclinical services	363	749
Manufacturing services	1,056	3,159
Accrued vacation	227	725
Payroll taxes and benefits	0	16
Other consulting services	66	199
Other	167	0
Total	$ 6,076	$ 16,589

Related Party Transactions - Ad

Related Party Transactions - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2015	Feb. 19, 2021
Related Party Transaction [Line Items]
Research and development	$ 49,643,000	$ 52,696,000
M.D. Anderson Cancer Center
Related Party Transaction [Line Items]
Payment	100,000	0
MD Anderson License and the Research and Development Agreement Member [Member]
Related Party Transaction [Line Items]
Cash resources on hand	0	8,100,000
License Agreement | M.D. Anderson Cancer Center
Related Party Transaction [Line Items]
Issuance of common stock in licensing agreement (in shares)			11,722,163
Research and development			$ 67,300,000
Vineti Inc [Member] | Collaborative Arrangement
Related Party Transaction [Line Items]
Expenses From Transactions With Related Party	400,000	$ 29,000,000
Watermill And Robert W Postma [Member]
Related Party Transaction [Line Items]
Amount due to related party, current				$ 400,000
Fees and Expenses, Related Party	650,000
Eden BioCell [Member]
Related Party Transaction [Line Items]
Payments to Fund Long-term Loans to Related Parties	10,000,000
Additional Loans Committed	$ 25,000,000

Leases - Components of Lease Ex

Leases - Components of Lease Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Operating lease cost	$ 1,394	$ 1,054
Total lease cost	$ 1,394	$ 1,054
Weighted-average remaining lease term (years)	5 years 6 months 29 days	6 years 2 months 8 days
Weighted-average discount rate	8.00%	8.00%

Leases - Operating Lease Liabil

Leases - Operating Lease Liabilities (Details) $ in Thousands	Dec. 31, 2021USD ($)
2022	$ 1,102
2023	1,132
2024	1,166
2025	1,201
2026	1,121
Thereafter	752
Total lease payments	6,474
Less: imputed interest and adjustments	(1,227)
Present value of lease payments	$ 5,247
Operating lease liability statement of financial position [extensible list]	Present value of lease payments

Leases - Additional Information

Leases - Additional Information (Details)	Aug. 31, 2021	Apr. 13, 2020	Oct. 15, 2019USD ($)ft²	Mar. 12, 2019USD ($)ft²	Dec. 31, 2021USD ($)ft²	Dec. 31, 2020USD ($)	Apr. 07, 2020USD ($)ft²	Jan. 30, 2018USD ($)ft²
Operating Lease, Payments					$ 1,300,000
Operating Lease Impairment Loss					600,000
Operating Lease Residual Value Of Leased Asset					1,400,000
Other Asset Impairment Charges					$ 100,000
Discounted Risk-adjusted Rate					10.00%
Operating lease expiration month and year		2027-02	2027-02
Operating Lease, Right-of-Use Asset					$ 4,420,000	$ 4,650,000
Operating Lease, Liability					5,247,000
Recognition in exchange of Operating Lease Liabilities					1,400,000
Boston, MA
Security Deposit					$ 100,000	$ 100,000
Sublease term amendment					Aug. 31, 2026
Operating lease expiration month and year	2026-08				2016-08
Houston, TX
Operating Lease Monthly Rental Payment				$ 2,000
Operating lease expiration month and year				2021-04
Operating Leases Future Minimum Monthly Payment Due Through Year 2021			$ 17,000		$ 37,000,000		$ 12,000,000	$ 1,000
Operating Lease Area | ft²			8,443	1,038	32,148		5,594	210
Annual base rent increase		3.00%	3.00%		3.00%

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail) - USD ($)

Sep. 01, 2020

Oct. 22, 2019

May 28, 2019

Jan. 13, 2015

Sep. 30, 2020

Jan. 31, 2020

Dec. 31, 2021

Dec. 31, 2020

Dec. 31, 2019

Dec. 31, 2017

Nov. 28, 2020

May 10, 2019

Feb. 19, 2019

May 10, 2018

Aug. 24, 2004

Accrued Payments

Incurred expenses

$ 500,000

$ 0

Research and development expense

49,643,000

52,696,000

Cash balance

76,054,000

115,069,000

Agreement commencement date

2015-05

Expected Cash Payment Payable

$ 1,500,000

Royalties amount payable thereafter

$ 100,000

Collaboration revenue

$ 398,000

0

MD Anderson Warrant [Member]

Accrued Payments

Number of Warrants

3,333,333

Warrant exercise per share

$ 0

Warrant Expiry date

Dec. 31, 2026

MD Anderson License and the Research and Development Agreement Member [Member]

Accrued Payments

Reimbursement of historical costs

$ 20,000,000

Accrued Payments

3,000,000

Aggregate potential benchmark payments

36,500,000

CRADA Agreement [Member]

Accrued Payments

Obligations due under contract

$ 5,000,000

Quarterly payments under contract

$ 1,250,000

2,500,000

C A R Products Member

Accrued Payments

Amount of royalties receivable

100,000,000

The University of Texas MD Anderson Cancer Center and The Texas A & M University System

Accrued Payments

Milestone maximum payment

$ 4,500,000

Payment under license agreement

0

Collaboration Agreement with Solasia Pharma K.K.

Accrued Payments

Collaboration revenue

400,000

0

MD Anderson License

Accrued Payments

Accrued expenses

8,100,000

12,200,000

Development costs paid

100,000

0

License Agreement with the National Cancer Institute [Member] | One Time Benchmark Payments [Member]

Accrued Payments

Accrued payments or receipts

100,000

Ziop License Agreement With The National Cancer Institute [Member]

Accrued Payments

Annual Licensing fee paid

$ 1,000,000

Reimbursement of historical costs

$ 46,000

Expected Cash Payment Payable

1,500,000

Expected cash payment payable per installments

500,000

Maximum royalties amount payable

$ 300,000

Description Of First Benchmark Payable

The first benchmark payment of $0.1 million will be due upon the initiation of our first sponsored Phase 1 clinical trial of a licensed product or licensed process in the field of use licensed under the Patent License

Description Of option To terminate Agreement

The NCI may terminate or modify the Patent License in the event of a material breach, including if we do not meet certain milestones by certain dates, or upon certain insolvency events that remain uncured following the date that is 90 days following written notice of such breach or insolvency event.

Agreement termination, notice period

60 days

60 days

payments under the Patent License

$ 411,000

$ 600,000

Ziop License Agreement With The National Cancer Institute [Member] | Performance Based Payments Member [Member]

Accrued Payments

Aggregate Benchmark Payments Payable

$ 4,300,000

Ziop License Agreement With The National Cancer Institute [Member] | One Time Benchmark Payments [Member]

Accrued Payments

Potential Benchmark Payments Payable

12,000,000

Ziop License Agreement With The National Cancer Institute [Member] | Post Marketing Approval [Member] | Performance Based Payments Member [Member]

Accrued Payments

Aggregate Benchmark Payments Payable

3,000,000

Ziop License Agreement With The National Cancer Institute [Member] | licensed products [Member] | One Time Benchmark Payments [Member]

Accrued Payments

Maximum Sales Revenue On Which Benchmark Payments Payable

1,000,000,000

Minimum sales revenue on which benchmark payments payable

$ 250,000,000

Patent And Technology License Agreement [Member] | The University of Texas MD Anderson Cancer Center and The Texas A & M University System

Accrued Payments

Accrued Payments

100,000

Prepaid Expenses and Other Current Assets | MD Anderson License

Accrued Payments

Cash balance

0

8,100,000

Intrexon Corporation

Accrued Payments

Annual Licensing fee

$ 100,000

Expected additional milestones payable

$ 52,500,000

Intrexon Corporation | T-cell receptor

Accrued Payments

Maximum royalty amount

$ 100,000,000

Portion of income payable to related party

20.00%

Maximum [Member] | MD Anderson License and the Research and Development Agreement Member [Member]

Accrued Payments

Research and development expense

$ 20,000,000

Minimum [Member] | MD Anderson License and the Research and Development Agreement Member [Member]

Accrued Payments

Research and development expense

$ 15,000,000

Minimum [Member] | License Agreement with the National Cancer Institute [Member]

Accrued Payments

Royalty fee

$ 500,000

Minimum [Member] | Ziop License Agreement With The National Cancer Institute [Member]

Accrued Payments

Royalty fee

$ 1,500,000

Warrants - Additional Informati

Warrants - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	Dec. 28, 2021	Aug. 06, 2021	Oct. 22, 2019	Sep. 12, 2019	Nov. 11, 2018	Dec. 31, 2021	Dec. 31, 2020
Fair Value Assumptions Expected volatility Rate Maximum						74.80%	74.41%
Fair Value Assumptions Risk Free Interest Rate Maximum						1.36%	1.68%
Net Proceeds from Underwriting							$ 13,016
Proceeds from private placement				$ 52,500
Silicon Valley Bank Loan [Member]
Warrant Exercise Per share		$ 2.22				$ 1.16
Number of warrants issued		432,844
MD Anderson Warrant [Member]
Number of securities into which the class of warrant converted			3,333,333
Warrant Exercise Per share			$ 0.001
Warrant Expiry date			Dec. 31, 2026
Fair value of adjustment of warrants			$ 14,500
Svb Warrants [Member]
Common stock		$ 432,844
Exercise price		2.22
Warrants fully vested upon issuance		10 years
Black Scholes Model [Member] | Silicon Valley Bank Loan [Member]
Fair Value Assumptions Expected Term1	10 years
Exercise price	1.16
Expected volatility	81.00%
Risk-free interest rate	1.49%
Dividends	$ 0
Number of warrants issued	649,615
Change in fair value	$ 200
Black Scholes Model [Member] | Svb Warrants [Member]
Fair Value Assumptions Expected Term1		10 years
Fair value of adjustment of warrants		$ 800
Expected volatility		79.00%
Risk-free interest rate		1.31%
Dividends		$ 0
Securities Purchase Agreement [Member]
Net Proceeds from Underwriting					$ 47,100
Private Placement [Member]
Number of securities into which the class of warrant converted				17,803,031	18,939,394
Warrant Exercise Per share				$ 3.01	$ 3.01
Fair Value Assumptions Expected volatility Rate Maximum					71.00%
Fair Value Assumptions Risk Free Interest Rate Maximum					2.99%
Fair Value Assumptions Expected Term1					5 years
Placement agent fees and other expenses				$ 1,100
Fair value of adjustment of warrants					$ 18,400
Dividends					$ 0
Private Placement [Member] | New Warrants [Member]
Number of securities into which the class of warrant converted				17,803,031
Warrant Exercise Per share				$ 7
Non-cash inducement warrant expense						$ 60,800

Restructuring - Future terminat

Restructuring - Future termination benefit payments resulting from the strategic reduction in force (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2021USD ($)
Restructuring Cost and Reserve [Line Items]
Severance Costs	$ 3,657
Research and Development
Restructuring Cost and Reserve [Line Items]
Severance Costs	2,368
General and Administrative
Restructuring Cost and Reserve [Line Items]
Severance Costs	$ 1,289

Income Taxes - Significant Comp

Income Taxes - Significant Component of Deferred Tax Assets (Detail) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Net operating loss carryforwards	$ 164,486	$ 147,004
Deferred tax assets:
Start-up and organizational costs	21,705	25,909
Research and development credit carryforwards	39,817	37,183
Stock compensation	706	1,478
Capitalized acquisition costs	2,946	3,691
Lease liability	1,278	1,225
Depreciation	102	71
Other	156	135
Deferred Tax Assets Gross	231,196	216,696
Less valuation allowance	(230,119)	(215,513)
Total deferred tax assets	1,077	1,183
Deferred tax liabilities:
Right of use asset	(1,077)	(1,183)
Total deferred tax liabilities	(1,077)	(1,183)
Net deferred taxes	$ 0	$ 0

Income Taxes - Reconciliation o

Income Taxes - Reconciliation of Income Tax Expense (Benefit) (Detail)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Federal income tax at statutory rates	21.00%	21.00%
State income tax, net of federal tax benefit	1.00%	3.00%
Research and development credits	2.00%	3.00%
Stock compensation	(1.00%)	(1.00%)
Research and development true-up	(2.00%)	0.00%
Federal rate change	(2.00%)	(2.00%)
Change in valuation allowance	(19.00%)	(24.00%)
Effective tax rate	0.00%	0.00%

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($) $ in Thousands	1 Months Ended	12 Months Ended
	Mar. 27, 2020	Dec. 31, 2021	Dec. 31, 2020
Income Taxes [Line Items]
Net operating loss carryforwards		$ 164,486	$ 147,004
Deferred tax assets operating loss carryforwards without expire date		297,000
Research and development credit carryforwards		39,817	37,183
Uncertain Tax Positions Adjustment		0	$ 0
Increase (decrease) in deferred tax assets		14,600
Covid 19
Income Taxes [Line Items]
Relaxation of taxable income, percentage	30.00%
Relaxation of Adjusted taxable income, percentage	50.00%
Covid 19 | Qualified Improvement Property
Income Taxes [Line Items]
Eligibility for bonus depreciation, percentage	100.00%
Estimated useful life	15
Domestic Tax Authority
Income Taxes [Line Items]
Net operating loss carryforwards		$ 639,000
Net operating loss carryforwards, expiration date		2037
Federal and State
Income Taxes [Line Items]
Deferred tax assets operating loss carryforwards with expire date		$ 342,000
Net operating loss carryforwards, expiration date		2041
Federal and State | Research Tax Credit Carryforward
Income Taxes [Line Items]
Research and development credit carryforwards		$ 40,000
State and Local Jurisdiction
Income Taxes [Line Items]
Net operating loss carryforwards		$ 480,000

Preferred Stock and Stockholder

Preferred Stock and Stockholders' Equity (Deficit) - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	Feb. 05, 2020	Nov. 11, 2018	Jun. 30, 2019	Dec. 31, 2021	Dec. 31, 2020
Equity [Line Items]
Common stock, shares authorized				350,000,000	250,000,000
Initial Public Offering of Common Stock				$ 0.001	$ 0.001
Net Proceeds from Underwriting					$ 13,016
Issuance of common stock in connection with a public offering, net				$ 0	$ 88,661
Common stock, shares outstanding				216,127,443	214,591,906
Common Stock [Member]
Equity [Line Items]
Common stock, shares authorized				350,000,000
Net Proceeds from Underwriting					$ 3
Common stock, shares outstanding				216,127,443
Common Stock, shares reserved for future issuance				33,620,711
Maximum [Member] | At The Market Offering [Member]
Equity [Line Items]
Net Proceeds from Underwriting			$ 100,000
Underwriting Agreement [Member]
Equity [Line Items]
Issuance of common stock in connection with a public offering, net	$ 84,800
Issuance & sale of common stock in public offering price per share	$ 3.25
Underwriting Agreement [Member] | At The Market Offering [Member]
Equity [Line Items]
Issuance of common stock in connection with a public offering, net					$ 13,000
Securities Purchase Agreement [Member]
Equity [Line Items]
Net Proceeds from Underwriting		$ 47,100

Stock Option Plan - Additional

Stock Option Plan - Additional information (Detail) - USD ($) $ / shares in Units, $ in Thousands	Nov. 21, 2019	Aug. 19, 2019	Jul. 22, 2019	Dec. 31, 2021	Dec. 31, 2020	Jun. 30, 2020	Dec. 31, 2019	May 31, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Outstanding options issued				10,665,869	6,840,719		5,842,879
Proceeds from stock options exercised				$ 1,036	$ 442
Total intrinsic value of options				$ 800	$ 300
Stock options, granted				9,380,438	2,222,368
Stock options granted exercise price				$ 2.62	$ 3.39
Options available for future grant				30,564
Common stock, shares authorized				350,000,000	250,000,000
Restricted Stock | Employees
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based payment award granted				1,601,224	805,900
Unvested Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation costs related to non-vested restricted stock outstanding				$ 8,100
Expected recognition period				2 years 1 month 6 days
Unvested Restricted Common Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected recognition period				2 years 1 month 24 days
Share-based payment award granted				1,601,224	805,900
Unrecognized stock-based compensation expense related to non-vested restricted stock arrangements				$ 2,100
the "2012 Plan"
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for future issuance								14,000,000
the "2012 Plan" | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for future issuance				2,847,190
Inducement Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Outstanding options issued				32,500
Stock options, granted	65,000	65,000	400,000
Stock options granted exercise price	$ 4.59	$ 5.18	$ 5.60
Share Based compensation arrangement by share based payment award options grants grant date fair value	$ 193,000	$ 231,000	$ 1,500
the "2020 Plan"
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized						21,000,000
Options available for future grant				1,066,275		22,066,275
Share Based Payment Award Shares Registered Due to Proximity On Authorized Shares				5,750,000
the "2020 Plan" | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for future issuance				7,818,679
the "2020 Plan" | Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Outstanding options issued				9,208,236
the "2020 Plan" | Director | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Outstanding options issued				1,397,633
the "2020 Plan" | Consultants | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Outstanding options issued				60,000

Stock Option Plan - Stock Optio

Stock Option Plan - Stock Option Activity Under Stock Option Plan (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Number of Shares
Beginning Balance	6,840,719	5,842,879
Granted	9,380,438	2,222,368
Exercised	(363,109)	(338,333)
Cancelled	(5,192,179)	(886,195)
Ending Balance	10,665,869	6,840,719
Options exercisable, at end of period	4,410,312	3,596,315
Options available for future grant	30,564
Weighted Average Exercise Price
Beginning Balance	$ 3.81	$ 3.21
Granted	2.62	3.39
Exercised	2.86	2.01
Cancelled	3.65	4.22
Ending Balance	2.87	3.81
Options exercisable, at end of period	$ 3.85	$ 4.17
Weighted Average Contractual Term (Years)
Outstanding, at end of period	8 years 8 months 1 day
Options exercisable, at end of period	7 years 6 months 10 days	6 years 10 months 24 days
Aggregate Intrinsic Value
Outstanding, at end of period	$ 0
Options exercisable, at end of period	$ 0	$ 598

Stock Option Plan - Summary of

Stock Option Plan - Summary of Non-Vested Restricted Stock (Detail) - Unvested Restricted Common Stock - $ / shares	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Number of Shares
Beginning Balance	786,280	939,636
Granted	1,601,224	805,900
Vested	(754,137)	(764,359)
Cancelled	(434,787)	(194,897)
Ending Balance	1,198,580	786,280
Weighted Average Grant Date Fair Value
Beginning Balance	$ 3.08	$ 2.93
Granted	2.60	3.75
Vested	3.40	3.51
Cancelled	3.45	3.44
Ending Balance	$ 2.10	$ 3.08

Employee Benefit Plan - Additio

Employee Benefit Plan - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Retirement Benefits [Abstract]
Defined benefit plan contributions by employer	$ 0.7	$ 0.5

Joint Venture - Additional Inf

Joint Venture - Additional Information (Detail) - USD ($) $ in Millions	Jul. 05, 2019	Dec. 31, 2021	Dec. 31, 2020	Jan. 03, 2019
Subsidiary or Equity Method Investee [Line Items]
Common stock, shares issued		216,127,443	214,591,906
Eden Bio Cell [Member]
Subsidiary or Equity Method Investee [Line Items]
Equity method investments		$ 0
Ziopharm [Member] | Eden Bio Cell [Member]
Subsidiary or Equity Method Investee [Line Items]
Equity interest in affilated entity	50.00%
Tri Arm [Member] | Eden Bio Cell [Member]
Subsidiary or Equity Method Investee [Line Items]
Equity interest in affilated entity	50.00%
Tri Arm [Member] | License Agreement Terms [Member] | Eden Bio Cell [Member]
Subsidiary or Equity Method Investee [Line Items]
Milestone payment made	$ 10
Conditional milestone amount payable	$ 25
Share Subscription Agreement [Member] | Ziopharm [Member] | Eden Bio Cell [Member]
Subsidiary or Equity Method Investee [Line Items]
Common stock, shares issued				10,000,000
Share Subscription Agreement [Member] | Tri Arm [Member] | Eden Bio Cell [Member]
Subsidiary or Equity Method Investee [Line Items]
Common stock, shares issued				10,000,000