0000950170-23-007062 | 10-K | XBRL Viewer | Oncternal Therapeutics INC

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Document and Entity Information - USD ($) $ in Millions	12 Months Ended
Document and Entity Information - USD ($) $ in Millions	Dec. 31, 2022	Mar. 03, 2023	Jun. 30, 2022
Cover [Abstract]
Entity Registrant Name	Oncternal Therapeutics, Inc.
Entity Central Index Key	0001260990
Document Type	10-K
Document Period End Date	Dec. 31, 2022
Amendment Flag	false
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	FY
Trading Symbol	ONCT
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Current Reporting Status	Yes
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		58,711,451
Entity Public Float			$ 52.7
Entity File Number	000-50549
Entity Tax Identification Number	62-1715807
Entity Address, Address Line One	12230 El Camino Real
Entity Address, Address Line Two	Suite 230
Entity Address, City or Town	San Diego
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	92130
City Area Code	858
Local Phone Number	434-1113
Entity Interactive Data Current	Yes
Title of 12(b) Security	Common Stock, par value $0.001 per share
Security Exchange Name	NASDAQ
Entity Incorporation, State or Country Code	DE
ICFR Auditor Attestation Flag	false
Document Annual Report	true
Document Transition Report	false
Documents Incorporated by Reference	Portions of the Registrant’s proxy statement to be filed with the Securities and Exchange Commission pursuant to Regulation 14A in connection with the Registrant’s 2023 Annual Meeting of Stockholders, which will be filed subsequent to the date hereof, are incorporated by reference into Part III of this Form 10-K. Such proxy statement will be filed with the Securities and Exchange Commission not later than 120 days following the end of the Registrant’s fiscal year ended December 31, 2022.
Auditor Name	BDO USA, LLP
Auditor Location	San Diego, California
Auditor Firm ID	243

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Current assets:
Cash and cash equivalents	$ 37,142	$ 90,765
Short-term investments	26,582	0
Prepaid and other	3,566	2,088
Total current assets	67,290	92,853
Right-of-use asset	87	75
Other assets	1,274	657
Total assets	68,651	93,585
Current liabilities:
Accounts payable	2,917	1,959
Accrued liabilities	4,678	3,431
Lease, current	87	75
Total current liabilities	7,682	5,465
Commitments and contingencies (Note 4)
Stockholders’ equity:
Preferred stock, $0.001 par value, authorized shares 5,000 at December 31, 2022 and 2021; issued and outstanding shares none	0	0
Common stock, $0.001 par value; authorized shares - 120,000 at December 31, 2022 and 60,000 at 2021; issued and outstanding shares - 57,464 and 49,429 at December 31, 2022 and 2021, respectively	57	49
Additional paid-in capital	219,203	202,201
Accumulated other comprehensive income	9	0
Accumulated deficit	(158,300)	(114,130)
Total stockholders’ equity	60,969	88,120
Total liabilities and stockholders’ equity	$ 68,651	$ 93,585

Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2022	Dec. 31, 2021
Statement of Financial Position [Abstract]
Preferred stock, par value	$ 0.001	$ 0.001
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized	120,000,000	60,000,000
Common stock, shares issued	57,464,000	49,429,000
Common stock, shares outstanding	57,464,000	49,429,000

Consolidated Statements of Operations and Comprehensive Loss - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Income Statement [Abstract]
Grant revenue	$ 1,490	$ 4,315
Operating expenses:
Research and development	32,980	24,086
General and administrative	13,457	11,595
Total operating expenses	46,437	35,681
Loss from operations	(44,947)	(31,366)
Interest income	777	33
Net loss	(44,170)	(31,333)
Other comprehensive loss:
Unrealized gain on available-for-sale securities, net	9
Comprehensive loss	$ (44,161)	$ (31,333)
Net loss per share, basic	$ (0.84)	$ (0.64)
Net loss per share, diluted	$ (0.84)	$ (0.64)
Weighted-average shares outstanding, basic	52,594	49,321
Weighted-average shares outstanding, diluted	52,594	49,321

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Cash flows from operating activities
Net loss	$ (44,170)	$ (31,333)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation	7,431	5,875
Amortization of premiums (accretion of discounts) on short-term investments	(75)	0
Noncash lease expense	179	169
Changes in operating assets and liabilities:
Prepaid and other assets	(2,095)	(713)
Accounts payable	958	816
Accrued liabilities	1,247	399
Change in lease liability	(179)	(169)
Deferred grant revenue	0	(1,633)
Net cash used in operating activities	(36,704)	(26,589)
Cash flows from investing activities
Purchases of available-for-sale securities	(26,498)	0
Net cash used in investing activities	(26,498)	0
Cash flows from financing activities
Proceeds from exercise of common stock options and warrants	0	617
Repurchases of common stock for tax withholding obligations	(3)	0
Proceeds from the issuance of common stock, net	9,582	0
Net cash provided by financing activities	9,579	617
Net decrease in cash and cash equivalents	(53,623)	(25,972)
Cash and cash equivalents at beginning of period	90,765	116,737
Cash and cash equivalents at end of period	37,142	90,765
Supplemental disclosure of non-cash investing and financing activities:
Cashless exercise of warrants	0	1,836
Right-of-use assets obtained in exchange for operating lease liabilities	$ 191	$ 0

Consolidated Statements of Convertible Preferred Stock and Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Income	Accumulated Deficit
Balance at Dec. 31, 2020	$ 112,951	$ 49	$ 195,699		$ (82,797)
Balance (in shares) at Dec. 31, 2020		48,802,000
Exercise of stock options for cash	415		415
Exercise of stock options for cash (in shares)		108,000
Cashless exercise of warrants		459,000
Exercise of warrants for cash	202		202
Exercise of warrants for cash (in shares)		60,000
Vesting related to repurchase liability	10		10
Stock-based compensation	5,875		5,875
Net loss	(31,333)				(31,333)
Balance at Dec. 31, 2021	$ 88,120	$ 49	202,201		(114,130)
Balance (in shares) at Dec. 31, 2021	49,429,000	49,429,000
Issuance of common stock, net of issuance cost of $375	$ 9,582	$ 8	9,574
Issuance of common stock, net of issuance cost (in shares)		8,031,000
Shares repurchased for settlement of minimum statutory tax withholdings	(3)		(3)
Issuance of common stock upon vesting of restricted stock units (in Shares)		6,000
Shares repurchased for settlement of minimum statutory tax withholdings (in shares)		(2,000)
Stock-based compensation	7,431		7,431
Unrealized gain on available-for-sale securities	9			$ 9
Net loss	(44,170)				(44,170)
Balance at Dec. 31, 2022	$ 60,969	$ 57	$ 219,203	$ 9	$ (158,300)
Balance (in shares) at Dec. 31, 2022	57,464,000	57,464,000

Condensed Consolidated Statements of Convertible Preferred Stock and Stockholders' Equity (Parenthetical) $ in Thousands	12 Months Ended
	Dec. 31, 2022 USD ($)
Statement of Stockholders' Equity [Abstract]
Common stock, issuance cost	$ 375

Description of Business, Basis of Presentation and Summary of Significant Accounting Policies

12 Months Ended

Dec. 31, 2022

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Description of Business, Basis of Presentation and Summary of Significant Accounting Policies

Description of Business

Oncternal Therapeutics, Inc. (the “Company,” “Oncternal,” or the “combined company”), formerly known as GTx, Inc., was incorporated in Tennessee in September 1997 and reincorporated in Delaware in 2003 and is based in San Diego, California. The Company is a clinical-stage biopharmaceutical company focused on the development of novel oncology therapies for the treatment of cancers with critical unmet medical need. The Company’s clinical pipeline includes zilovertamab, a humanized monoclonal antibody that binds to ROR1 (Receptor-tyrosine kinase-like Orphan Receptor 1). The Company is also developing ONCT-808, a CAR T (chimeric antigen receptor T-cells) product candidate that targets ROR1 and ONCT-534, a dual-action androgen receptor inhibitor product candidate for the treatment of castration-resistant prostate and other androgen receptor-driven cancers.

Principles of Consolidation

The consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries, Oncternal Oncology, Inc. and Oncternal, Inc. All intercompany accounts and transactions have been eliminated in the preparation of the consolidated financial statements.

Going Concern

The financial statements have been prepared assuming the Company will continue as a going concern, which contemplates the realization of assets and the satisfaction of liabilities in the normal course of business. From inception, the Company has devoted substantially all of its efforts to drug discovery and development and conducting preclinical studies and clinical trials. The Company has a limited operating history and the sales and income potential of the Company’s business and market are unproven. Successful transition to attaining profitable operations is dependent upon achieving a level of revenues adequate to support the Company’s cost structure.

As of December 31, 2022, the Company had $63.7 million in cash, cash equivalents, and short-term investments, no debt and an accumulated deficit of $158.3 million. From its inception, the Company has incurred recurring operating losses and negative cash flows. The Company has concluded that the balance of cash, cash equivalents and short-term investments may not be sufficient to fund its planned expenditures and meet its obligations for the twelve months following the financial statement issuance date without raising additional funding or making changes to its operating plans or programs to reduce expenses. As a result, there is substantial doubt about the Company’s ability to continue as a going concern for twelve months following the issuance date of the consolidated financial statements as of December 31, 2022. The consolidated financial statements have been prepared assuming the Company will continue as a going concern and do not include any adjustments that might result from the outcome of this uncertainty.

The Company expects to continue to incur net losses for the foreseeable future and believes it will need to raise substantial additional capital to accomplish its business plan over the next several years. The Company plans to continue to fund its losses from operations and capital funding needs through a combination of public or private equity or debt offerings or other sources, including potential collaborations, strategic alliances and other similar licensing arrangements in both the short term and long term. If the Company is unable to secure adequate additional funding, the Company may be forced to make reductions in spending, including potentially delaying, scaling back or eliminating certain of our pipeline development programs, extend payment terms with suppliers, or liquidate assets where possible. Any of these actions could materially harm the Company’s business, results of operations and future prospects.

As of December 31, 2022, the Company had capacity to issue up to an additional $40.0 million of shares of common stock under its at-the-market (“ATM”) equity offering program. Through December 31, 2022, the Company has sold 8,031,355 shares of common stock for net proceeds of $9.6 million under the ATM program. There can be no assurance that the Company will be able to sell any additional shares of its common stock under the ATM program and no assurance regarding the price at which it will be able to sell any such shares, and any sales of shares of its common stock under the ATM program may be at prices that result in additional dilution to existing stockholders of the Company.

The Company's ability to obtain additional financing (including through collaborating and licensing arrangements) will depend on a number of factors, including, among others, its ability to generate positive data from its clinical trials and preclinical studies, the condition of the capital markets and the other risks, many of which are dependent on factors outside of its control. There can be no assurance as to the availability or terms upon which such financing and capital might be available in the future.

Use of Estimates

The Company’s consolidated financial statements are prepared in accordance with GAAP. The preparation of the Company’s consolidated financial statements and accompanying notes requires it to make estimates and assumptions that impact the reported amounts of assets, liabilities, revenues and expenses and the disclosure of contingent assets and liabilities. Significant estimates consist of those used to determine the fair value of the Company’s stock-based awards, and those used to determine grant revenue and accruals for research and development costs. Although these estimates are based on the Company’s knowledge of current events and actions it may undertake in the future, actual results may ultimately materially differ from these estimates and assumptions.

Cash and Cash Equivalents

The Company considers all highly liquid investments with maturities of three months or less when purchased to be cash equivalents. Cash and cash equivalents include cash in readily available checking accounts, money market accounts and commercial paper.

Short-term Investments

The Company carries short-term investments classified as available-for-sale marketable securities at fair value as determined by prices for identical or similar securities at the balance sheet date. Short-term investments consist of Level 1 and Level 2 financial instruments in the fair value hierarchy (see Note 6 – Fair Value). Realized gains or losses on available-for-sale securities are determined using the specific identification method and net realized gains and losses are included in interest income. The Company periodically reviews available-for-sale securities for other-than-temporary declines in fair value below the cost basis, and whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. The Company records unrealized gains and losses on available-for-sale marketable securities as a component of other comprehensive loss within the statements of comprehensive loss and as a separate component of stockholders’ equity on the balance sheets. In accordance with policy, the Company does not invest in or hold equity securities in its investment portfolio.

Concentration of Credit Risk

Financial instruments that potentially subject the Company to significant concentrations of credit risk consist primarily of cash, cash equivalents and short-term investments. The Company maintains deposits in federally insured financial institutions in excess of federally insured limits. The Company has not experienced any losses in such accounts and believes it is not exposed to significant risk on its cash balances due to the financial position of the depository institution in which those deposits are held. Additionally, the Company established guidelines regarding approved investments and maturities of investments, which are designed to maintain safety and liquidity.

Patent Costs

Costs related to filing and pursuing patent applications are recorded as general and administrative expense and expensed as incurred since recoverability of such expenditures is uncertain.

Research and Development Expenses and Accruals

Research and development expenses consist of costs incurred for the Company’s own and for sponsored and collaborative research and development activities. Research and development costs are expensed as incurred and include manufacturing process development costs, manufacturing costs, costs associated with preclinical studies and clinical trials, regulatory and medical affairs activities, quality assurance activities, salaries and benefits, including stock-based compensation, fees paid to third-party consultants, license fees and overhead.

The Company has entered into various research and development contracts with research institutions, clinical research organizations, clinical manufacturing organizations and other companies. Payments for these activities are based on the terms of the individual agreements, which may differ from the pattern of costs incurred, and payments made in advance of performance are reflected in the accompanying consolidated balance sheets as prepaid and other assets or accrued liabilities. The Company records accruals for estimated costs incurred for ongoing research and development activities. When evaluating the adequacy of the accrued liabilities, the Company analyzes progress of the services, including the phase or completion of events, invoices received and contracted costs. Significant judgments and estimates may be made in determining the prepaid or accrued balances at the end of any reporting period. Actual results could differ from the Company’s estimates.

Fair Value Measurements

The Company’s financial instruments include cash, cash equivalents, short-term investments, prepaid expenses and other assets, accounts payable, accrued expenses, and accrued compensation. The carrying amounts of the Company’s current financial assets and liabilities are considered to be representative of their respective fair values because of the short-term nature of those instruments. The Company has short-term investments that are measured at fair value on a recurring basis. No transfers between levels have occurred during the periods presented (see Note 6 – Fair Value).

Revenue Recognition

The Company generates revenue from certain grant awards or a research subaward (the “Grant Awards”) (see Note 5), which provides the Company with payments in return for certain research and development activities over a contractually defined period. Revenue from such Grant Awards is recognized in the period during which the related qualifying services are rendered and costs are incurred, provided that the applicable conditions under the Grant Awards have been met.

The Grant Awards are on a best-efforts basis and do not require scientific achievement as a performance obligation. The Grant Awards are non-refundable. The costs associated with the Grant Awards are expensed as incurred and reflected as a component of research and development expense in the accompanying consolidated statements of operations.

Funds received from the Grant Awards are recorded as revenue as the Company is the principal participant in the arrangement because the activities under the Grant Awards are part of the Company’s development programs. In those instances where the Company first receives consideration in advance of providing underlying services, the Company classifies such consideration as deferred revenue until (or as) the Company provides the underlying services. In those instances where the Company first provides the underlying services prior to its receipt of consideration, the Company records a grant receivable.

Stock-Based Compensation

Stock-based compensation expense represents the fair value of equity awards, on the grant date, recognized in the period using the Black- Scholes option pricing model. The Company recognizes expense for awards with graded vesting schedules over the requisite service period of the awards (usually the vesting period) on a straight-line basis. For equity awards for which vesting is subject to performance-based milestones, the expense is recorded over the remaining service period after the point when the achievement of the milestone is probable. The Company recognizes forfeitures for all awards as such forfeitures occur.

Income Taxes

The Company accounts for income taxes under the asset and liability method, which requires the recognition of deferred tax assets and liabilities for the expected future tax consequences of events that have been included in the consolidated financial statements. Under this method, deferred tax assets and liabilities are determined on the basis of the differences between the financial statements and tax basis of assets and liabilities using enacted tax rates in effect for the year in which the differences are expected to reverse. The effect of a change in tax rates on deferred tax assets and liabilities is recognized in income in the period that includes the enactment date.

The Company recognizes net deferred tax assets to the extent that the Company believes these assets are more likely than not to be realized. In making such a determination, management considers all available positive and negative evidence, including future reversals of existing taxable temporary differences, projected future taxable income, tax-planning strategies, and results of recent operations. If management determines that the Company would be able to realize its deferred tax assets in the future in excess of their net recorded amount, management would make an adjustment to the deferred tax asset valuation allowance, which would reduce the provision for income taxes.

Segment Reporting

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 in making decisions regarding resource allocation and assessing performance. The Company views its operations and manages its business in one operating segment in the United States.

Net Loss Per Share

Basic net loss per share is computed by dividing the net loss by the weighted-average number of common shares outstanding for the period, without consideration for potentially dilutive securities and adjusted for the weighted-average number of common shares outstanding that are subject to repurchase. The Company has excluded weighted-average shares subject to repurchase of zero shares and 7,000 shares from the weighted-average number of common shares outstanding for the years ended December 31, 2022 and 2021, respectively. Diluted net loss per share is computed by dividing the net loss by the weighted-average number of shares of common stock and dilutive common stock equivalents outstanding for the period determined using the treasury-stock and if-converted methods. For all periods presented, there is no difference in the number of shares used to calculate basic and diluted shares outstanding as inclusion of the potentially dilutive securities would be antidilutive.

Potentially dilutive securities not included in the calculation of diluted net loss per share, because to do so would be anti-dilutive, are as follows (in common stock equivalent shares; in thousands):


	December 31,
	2022		2021
Warrants to purchase common stock		3,411		4,235
Common stock options		8,516		6,445
Restricted stock units		1,009		—
		12,936		10,680

Recently Adopted Accounting Pronouncements

In May 2021, the FASB issued ASU 2021-04, Earnings Per Share (Topic 260), Debt-Modifications and Extinguishments (Subtopic 470-50), Compensation-Stock Compensation (Topic 718), and Derivatives and Hedging-Contracts in Entity’s Own Equity (Subtopic 815-40): Issuer’s Accounting for Certain Modifications or Exchanges of Freestanding Equity-Classified Written Call Options, which intends to clarify and reduce diversity in an issuer’s accounting for modifications or exchanges of freestanding equity-classified written call options (for example, warrants) that remain equity classified after modification or exchange. The guidance requires transition disclosures of the nature of and reasons for the accounting change, the transition method, and a qualitative description of the financial statement line items affected. The Company adopted this guidance effective January 1, 2022 and there were no modifications or exchanges of freestanding equity-classified written call options subject to ASU 2021-04 during the periods presented.

Accounting Standards Not Yet Adopted

In June 2016, the FASB issued ASU 2016-13, Financial Instruments - Credit Losses: Measurement of Credit Losses on Financial Statements (Topic 362), which intends to improve financial reporting by requiring earlier recognition of credit losses on certain financial assets, such as available-for-sale debt securities. Subsequent to the issuance of ASU 2016-13, the FASB issued several additional ASUs to clarify implementation guidance, provide narrow scope improvements and provide additional disclosure guidance. In November 2019, the FASB issued an amendment making this ASU effective for fiscal years beginning after December 15, 2022 for smaller reporting companies. The Company was a smaller reporting company at the determination date, and therefore the new

standard will be effective for the Company on January 1, 2023. An entity must apply the amendments through a cumulative-effect adjustment to retained earnings as of the beginning of the first reporting period in which the guidance is effective (that is, a modified-retrospective approach), except in certain circumstances. The Company plans to adopt this guidance effective January 1, 2023, and has determined that the adoption of this standard is not expected to have a material effect on the Company’s consolidated results of operations or financial position.

Balance Sheet Details

12 Months Ended

Dec. 31, 2022

Payables and Accruals [Abstract]

Balance Sheet Details

Prepaid and other consist of the following (in thousands):


	December 31,		December 31,
	2022		2021
Research and development	$	—	$	294
Clinical trials		2,616		—
Insurance		669		765
Other prepaid expenses		103		85
Related party receivable (see Note 4)		—		359
Grant and other receivable		178		585
	$	3,566	$	2,088

Accrued liabilities consist of the following (in thousands):


	December 31,		December 31,
	2022		2021
Research and development	$	972	$	779
Clinical trials		868		518
Legal fees		138		154
Compensation		2,691		1,955
Other		9		25
	$	4,678	$	3,431

Marketable Securities

12 Months Ended

Dec. 31, 2022

Investments, Debt and Equity Securities [Abstract]

Marketable Securities

The Company invests in available-for-sale marketable securities consisting of money market funds, commercial paper, certificates of deposit, U.S. Treasury securities and U.S. government sponsored enterprise securities. Available-for-sale marketable securities are classified as part of either cash, cash equivalents or short-term investments in the balance sheets. Available-for-sale marketable securities with maturities of three months or less from the date of purchase have been classified as cash equivalents, and were $37.1 million and $90.8 million as of December 31, 2022 and 2021, respectively.

Available-for-sale marketable securities with original maturities of more than three months from the date of purchase as of December 31, 2022 have been classified as short-term investments and are measured at a fair value on a recurring basis, and were as follows (in thousands):



	Maturity (in years)	Amortized Cost		Unrealized Gains		Unrealized Losses		Fair Market Value
Cash and cash equivalents:
Money market funds	1 or less	$	25,108	$	—	$	—	$	25,108
U.S. Treasury debt securities	1 or less		1,996		—		—		1,996
U.S. Government Agency	1 or less		1,991		—		—		1,991
Total cash and cash equivalents		$	29,095	$	—	$	—	$	29,095
Short term investments:
U.S. Treasury debt securities	1 or less	$	21,681	$	7	$	—	$	21,688
Commercial Paper	1 or less		2,936		—		—		2,936
U.S. Government Agency	1 or less		1,956		2		—		1,958
Total short-term investments		$	26,573	$	9	$	—	$	26,582

Total marketable securities		$	55,668	$	9	$	—	$	55,677

At each reporting date, the Company performs an evaluation of impairment to determine if any unrealized losses are other-than-temporary. Factors considered in determining whether a loss is other-than temporary include the length of time and extent to which fair value has been less than the cost basis, the financial condition of the issuer, and the Company’s intent and ability to hold the investment until recovery of its amortized cost basis. The Company intends, and has the ability, to hold any investments in unrealized loss positions until their amortized cost basis has been recovered. The Company determined there were no other-than-temporary declines in the value of any available-for-sale securities as of December 31, 2022. All the Company’s available-for-sale marketable securities mature within one year.

The Company obtains the fair value of its available-for-sale marketable securities from a professional pricing service. The fair values of available-for-sale marketable securities are validated by comparing the fair values reported by the professional pricing service to quoted market prices or to fair values obtained from the custodian bank. The service provider values the securities using a hierarchical security pricing model that relies primarily on valuations provided by an industry-recognized valuation service or mathematical calculations. Such valuations may be based on trade prices in active markets for identical assets or liabilities (Level 1 inputs) or valuation models using inputs that are observable either directly or indirectly (Level 2 inputs), such as quoted prices for similar assets or liabilities, yield curves, credit spreads, current market and contractual prices for the underlying instruments or debt, as well as other relevant economic measures.

Commitments, Contingencies and Related Party Transactions

12 Months Ended

Dec. 31, 2022

Commitments and Contingencies Disclosure [Abstract]

Commitments, Contingencies and Related Party Transactions

Lease

Rent expense was $0.2 million for the years ended December 31, 2022 and 2021. From May 2019 through April 30, 2022, the Company leased office space in San Diego, California. On April 18, 2022, the Company entered into a sublease agreement for office space in San Diego, California which expires on July 31, 2023 (the “San Diego Lease”). Base rent under the San Diego Lease is approximately $157,000 annually and the monthly rent expense is being recognized on a straight-line basis over the lease term.

The San Diego Lease is included in the accompanying consolidated balance sheet at the present value of the lease payments. As the San Diego Lease does not have an implicit interest rate, the present value reflects a 10.0% discount rate which is the estimated rate of interest that the Company would have to pay in order to borrow an amount equal to the lease payments on a collateralized basis over a similar term and in a similar economic environment. As of December 31, 2022, the Company has recognized a net operating lease right-of-use asset and a lease liability of $87,000 that matures in July 2023, which has a weighted average remaining lease term of 0.6 years.

Related Party Transactions

Effective in September 2019, the Company and Shanghai Pharmaceutical (USA) Inc. (“SPH USA”) entered into a Materials Supply and Services Agreement (“SPH USA Services Agreement”), pursuant to which the Company and SPH USA will execute various statements of work for the transfer to SPH USA of key reagents and other materials, and for the supply of certain services by the Company to SPH USA, as contemplated under and in furtherance of the License and Development Agreement between the Company and SPH USA effective as of November 2018. As of December 31, 2022 and 2021, the Company had none and $0.4 million in amounts receivable from SPH USA related to statements of work. SPH USA is the Company’s largest stockholder and an affiliate of one of the Company’s directors.

License, Collaboration, Grants, Research Subaward Agreement and CVR Agreements

12 Months Ended

Dec. 31, 2022

Organization, Consolidation and Presentation of Financial Statements [Abstract]

License, Collaboration, Grants, Research Subaward Agreement and CVR Agreements

Georgetown University (“Georgetown”)

In March 2014, the Company entered into an Exclusive License Agreement (the “Georgetown License Agreement”) with Georgetown, pursuant to which the Company: (i) licensed the exclusive worldwide right to patents and technologies for the development and commercialization of certain product candidates targeting EWS-FLI1 as an anti-tumor therapy for therapeutic, diagnostics, or research tool purposes, (ii) is solely responsible for all development and commercialization activities and costs, and (iii) is responsible for all costs related to the filing, prosecution and maintenance of the licensed patent rights.

Under the terms of the Georgetown License Agreement, commencing in 2015, the Company: (i) shall pay and has paid an annual license maintenance fee of $10,000 until the first commercial sale occurs, (ii) is required to make up to $0.2 million in aggregate milestone payments upon the achievement of certain regulatory milestones, and (iii) will be required to pay low single digit royalties based on annual net product sales. The Company accounted for the licensed technology as an asset acquisition because it did not meet the definition of a business. All milestone payments under the Georgetown License Agreement will be recognized as research and development expense upon completion of the required events, as the triggering events are not considered to be probable until they are achieved.

The Georgetown License Agreement may be terminated by either party upon material breach or may be terminated by the Company as to one or more countries with 90 days written notice of termination. The term of the Georgetown License Agreement will continue until the expiration of the last valid claim within the patent rights covering the product. Georgetown may terminate the agreement in the event: (i) the Company fails to pay any amount and fails to cure such failure within 30 days after receipt of notice, (ii) the Company defaults in its obligation to obtain and maintain insurance and fails to remedy such breach within 60 days after receipt of notice, or (iii) the Company declares insolvency or bankruptcy. The Company may terminate the Georgetown License Agreement at any time upon at least 60 days’ written notice.

The University of Texas MD Anderson Cancer Center (“MD Anderson”)

In December 2014, the Company entered into a collaboration agreement (as amended, the “Collaboration”) with MD Anderson, which provides for the conduct of preclinical and clinical research for ONCT-216 in exchange for certain program payments. If MD Anderson successfully completes all the requirements of the Collaboration in full and the program is successfully commercialized, the Company will be required to pay aggregate milestone payments of $1.0 million based on net product sales. In July 2020 and September 2021, the Company entered into two research agreements with MD Anderson for certain services up to an aggregate cost of $0.8 million. The amount recorded as research and development expense for the years ended December 31, 2022 and 2021 was $0.5 million and $0.1 million, respectively.

Agreements with the Regents of the University of California (the “Regents”)

In March 2016, and as amended and restated in August 2018, and as amended in March and May 2019 and February 2021, the Company entered into a license agreement (as amended and restated, the “Regents License Agreement”) for the development, manufacturing and distribution rights related to the development and commercialization of ROR1 related naked antibodies, antibody fragments or synthetic antibodies, and genetically engineered cellular therapy. The Regents License Agreement provides for the following: (i) in May 2016, an upfront license fee of $0.5 million was paid and 107,108 shares of common stock were issued, (ii) $25,000 in annual license maintenance fees commencing in 2017, (iii) reimbursement of certain annual patent costs, (iv) certain development and regulatory milestones aggregating from $20.1 million to $24.5 million, on a per product basis, (v) certain worldwide sales milestones based on achievement of tiered revenue levels aggregating $75.0 million, (vi) low single-digit royalties, including potential future minimum annual royalties, on net sales of each target, and (vii) minimum diligence to advance licensed assets consisting of at least $1.0 million in development spend annually through 2021. Under the Regents License Agreement, the Company recorded: (i) $25,000 in license maintenance fees as research and development expense for each of the years ended December 31, 2022 and 2021, and (ii) approximately $0.1 million and $0.3 million in patent costs as general and administrative expense for the years ended December 31, 2022 and 2021, respectively.

The Regents License Agreement will expire upon the later of the expiration date of the longest-lived patent rights or the 15th anniversary of the first commercial sale of a licensed product. The Regents may terminate the Regents License Agreement if: (i) a material breach by the Company is not cured within a reasonable time, (ii) the Company files a claim asserting the Regents licensed patent rights are invalid or unenforceable and (iii) the Company files for bankruptcy. The Company may terminate the agreement at any time upon at least 60 days’ written notice.

In July 2016, and as modified by the amended and restated Regents License Agreement in August 2018, the Company entered into a research agreement with the Regents for research on a ROR1 therapeutic development program. Under this five-year agreement that expired in 2021, the Regents was paid an aggregate of $3.6 million, including $0.3 million for the year ended December 31, 2021. Effective January 1, 2022, the Company entered into a Research Agreement (the “Research Agreement”) with the Regents for further research on a ROR1 therapeutic development program. Under this four-year agreement that expires on December 31, 2025, the Regents will receive payments aggregating $1.6 million, with quarterly payments of $125,000 in 2022, $131,250 in 2023, and $137,813 in 2024. The Company recorded $0.5 million in research and development expense under this agreement in the year ended December 31, 2022.

University of Tennessee Research Foundation (“UTRF”)

In March 2015, and as amended and restated in March 2022 and August 2022, the Company and UTRF entered into a license agreement (the “DAARI License Agreement”) pursuant to which the Company was granted exclusive worldwide rights in all existing selective androgen receptor degrader technologies owned or controlled by UTRF, including all improvements thereto, which is now known as the dual action androgen receptor inhibitor, or DAARI program. Under the DAARI License Agreement, the Company is obligated to employ active, diligent efforts to conduct preclinical research and development activities for the DAARI program to advance one or more lead compounds into clinical development. The Company is also obligated to pay UTRF annual license maintenance fees, low single-digit royalties on net sales of products and additional royalties on sublicense revenues, depending on the state of development of a clinical product candidate at the time it is sublicensed. The Company recorded research and development expenses under this agreement of $0.3 million and $0.1 million for each of the years ended December 31, 2022 and 2021, respectively.

The California Institute for Regenerative Medicine (“CIRM”) Award

In August 2017, and as amended and restated in December 2020, CIRM awarded an $18.3 million grant to researchers at UC San Diego to advance the Company’s Phase 1/2 clinical trial evaluating zilovertamab in combination with ibrutinib for the treatment of patients with B-cell lymphoid malignancies, including chronic lymphocytic leukemia (“CLL”) and mantle cell lymphoma (“MCL”). This is known as Study CIRM-0001. The Company: (i) is conducting this study in collaboration with UC San Diego, (ii) received $14.5 million in

development milestones under research subaward agreements throughout the award project period from October 1, 2017 to March 31, 2022, (iii) was committed to certain co-funding requirements, (iv) received subaward payments of $0.7 million and $2.2 million in the years ended December 31, 2022 and 2021, respectively, and (v) was required to provide UC San Diego progress and financial update reports throughout the award period. The subaward does not bear a royalty payment commitment, nor is the subaward otherwise refundable. For the years ended December 31, 2022 and 2021, the Company’s grant revenue was $0.4 million and $4.2 million, respectively. Related qualifying subaward costs for the years ended December 31, 2022 and 2021 were $0.5 million and $8.8 million, respectively.

In October 2017, CIRM awarded a $5.8 million grant to the researchers at the University of California San Diego School of Medicine (“UC San Diego”) to develop a novel anti-cancer stem cell targeted therapy for patients with advanced solid and hematological malignancies. In connection with such CIRM award, the Company agreed to provide up to $1.0 million in contingency funds if required during the grant period. The Company recorded no research and development expense, and no contingency funds have been provided under such CIRM award for the years ended December 31, 2022 and 2021. The grant expired in 2021 and the Company believes there are no obligations as of December 31, 2022.

The National Institutes of Health (“NIH”) Grant Awards

In August 2021, the NIH awarded the Company two research and development grants for up to $2.2 million to support preclinical activities for the Company’s ONCT-216 and ONCT-534 programs, including $0.7 million payable to subawardees. Under the terms of the grant awards, the Company is entitled to receive reimbursement in arrears of incurring allowable expenditures. The earned NIH funds are non-refundable and the Company is required to provide periodic progress performance reports. During the year ended December 31, 2022, the Company received $1.2 million in award payments from the NIH. During the years ended December 31, 2022 and 2021, the Company recorded $1.1 million and $0.1 million, respectively, in grant revenue and had $0.1 million in unbilled receivables as of December 31, 2022 and 2021, which has been included in prepaid and other assets.

Clinical Trial and Supply Agreement

In April 2018, and as amended in August 2019, the Company entered into a Clinical Trial and Supply Agreement with Pharmacyclics, LLC, an AbbVie Company, to supply ibrutinib for the Study CIRM-0001. Effective in June 2022, the Company entered into a Clinical Trial and Supply Agreement with Pharmacyclics, LLC, to supply ibrutinib for the Company’s global Study ZILO-301. Such agreements do not bear any upfront costs, inventory purchase costs, milestone or royalty payment commitments or other financial obligations.

SPH USA, a Related Party

License and Development Agreement (“LDA”)

In November 2018, and as amended in August 2020, the Company entered into the LDA with SPH USA for: (i) the territory of the People’s Republic of China, Hong Kong, Macau, and Taiwan (“Greater China”), and (ii) rights to manufacture, develop, market, distribute and sell all of the Company’s product candidates under the Georgetown License Agreement and the Regents License Agreement (exclusive to Greater China only). Under the LDA, SPH USA is solely responsible for: (a) all preclinical and clinical development activities required in order to obtain regulatory approval in Greater China for such product candidates, (b) any third-party license milestone or royalty payments owed under the Georgetown License Agreement and the Regents License Agreement, and (c) paying the Company a low single digit royalty on net sales in the territory.

The LDA will expire upon the expiration of the last royalty term for the last licensed product. The LDA may be terminated by: (i) SPH USA on a country/region-by-country/region or product by product basis with 180 days written notice, (ii) either party upon material breach that is not cured within 90 days, and (iii) either party in the event the other party declares insolvency or bankruptcy. There has been no significant activity under this agreement for the years ended December 31, 2022 and 2021. See Note 4.

Contingent Value Rights Agreement (“CVR Agreement”)

Pursuant to the GTx merger agreement entered into in June 2019 (the “Merger”), the Company, a representative of holders of the CVRs, and Computershare, Inc. as rights agent entered into the CVR Agreement. Pursuant to the CVR Agreement, the Company’s stockholders of record as of immediately prior to the Merger received one CVR for each share of the Company’s common stock held immediately prior to the Merger.

As amended on November 1, 2021, the CVR Agreement entitles holders of CVRs to receive: (i) 50% of certain net proceeds received by the Company during the 15-year period after the closing of the Merger (the “CVR Term”) from a transaction, if any, resulting in the grant, sale, or transfer of DAARI technology to a third party that occurs during the 10-year period after the closing of the Merger (or in the 11th year if based on a term sheet approved during the initial 10-year period); and (ii) 5% of net sales of products by Parent or its affiliates during the CVR Term incorporating the DAARI technology. As of December 31, 2022, no transactions or net sales relating to the DAARI technology had occurred.

Fair Value

12 Months Ended

Dec. 31, 2022

Fair Value Disclosures [Abstract]

Fair Value

The accounting guidance defines fair value, establishes a consistency framework for measuring fair value and expands disclosure for each major asset and liability category measured at fair value on either a recurring basis or nonrecurring basis. Fair value is defined as an exit price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants on the measurement date. Accounting guidance establishes a three-tier fair value hierarchy that requires an entity to maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value. These tiers are based on the source of the inputs and are as follows:

Level 1: Observable inputs such as quoted prices in active markets for identical assets or liabilities.

Level 2: Inputs other than quoted prices in active markets that are observable either directly or indirectly.

Level 3: Unobservable inputs in which there is little or no market data, which require the reporting entity to develop its own assumptions.

As of December 31, 2022, the following fair value hierarchy table presents the Company’s financial assets measured at fair value on a recurring basis (in thousands):


	Total		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
As of December 31, 2022
Assets:
Cash and cash equivalents:
Money market funds	$	25,108	$	25,108	$	—	$	—
U.S. Treasury debt securities		1,996		1,996		—		—
U.S. Government Agency		1,991		—		1,991		—
Total cash and cash equivalents	$	29,095	$	27,104	$	1,991	$	—
Short term investments:
U.S. Treasury debt securities	$	21,688	$	21,688	$	—	$	—
Commercial Paper		2,936		—		2,936		—
U.S. Government Agency		1,958		—		1,958		—
Total short-term investments	$	26,582	$	21,688	$	4,894	$	—

Total assets measured at fair value	$	55,677	$	48,792	$	6,885	$	—

The Company had no current financial assets or liabilities measured at fair value during the year ended December 31, 2021. The Company’s policy is to recognize transfers between levels of the fair value hierarchy on

the date of the event or change in circumstances that caused the transfer. There were no transfers into or out of Level 3 during the years ended December 31, 2022 and 2021.

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

Stockholders' Equity

12 Months Ended

Dec. 31, 2022

Equity [Abstract]

Stockholders' Equity

Stockholders’ Equity

Amended and Restated Articles of Incorporation

On May 25, 2021, the Company’s certificate of incorporation was amended and restated to authorize 120,000,000 shares of common stock and 5,000,000 shares of undesignated preferred stock, each with a par value of $0.001 per share.

ATM Program

In December 2021, the Company entered into an Open Market Sale AgreementSM (the “Sales Agreement”) with Jefferies LLC, pursuant to which the Company is able to offer and sell, from time to time in its sole discretion, shares of its common stock having an aggregate offering price of up to $50.0 million. The Company has no obligation to sell any shares under the Sales Agreement and may at any time suspend solicitation and offers under the Sales Agreement. During the years ended December 31, 2022 and 2021, the Company sold 8,031,355 and zero shares of common stock for net proceeds of $9.6 million and zero, respectively.

Common Stock Warrants

A summary of warrant activity and changes in warrants outstanding is presented below:


	Number of Shares Underlying Warrants			Weighted-Average Exercise Price per Share		Weighted-Average Remaining Contractual Term
Balance Outstanding - December 31, 2020		5,031,841		$	9.25		4.40
Exercised		(796,931	)		2.56		—
Balance Outstanding - December 31, 2021		4,234,910			10.50		3.31
Expired		(824,268	)		38.64		—
Balance Outstanding - December 31, 2022		3,410,642		$	3.70		2.94

As of December 31, 2022 and 2021, all warrants met the criteria for classification in stockholders’ equity.

Equity Incentive Plans

Contemporaneous with the Merger closing: (i) Oncternal’s 2015 Equity Incentive Plan, as amended (“2015 Plan”) was assumed by the Company, and (ii) the Company adopted the 2019 Incentive Award Plan (“2019 Plan”) under which the sum of: (a) 1,954,150 shares of common stock, and (b) an annual increase on the first day of each calendar year beginning January 1, 2020, and ending on and including January 1, 2029, equal to the lesser of (A) 5% of the aggregate number of shares of common stock outstanding on the final day of the immediately preceding calendar year and (B) such smaller number of shares of common stock as is determined by the Board, are reserved for issuance.

In July 2015, Oncternal adopted the 2015 Plan which provided for the issuance of shares of common stock for incentive stock options, non-statutory stock options, restricted stock awards, restricted stock unit awards and other stock awards to its employees, members of its board of directors and consultants. In general, the options issued under the 2015 Plan expire ten years from the date of grant and vest over a four-year period. Certain grants vest based on the achievement of development or regulatory milestones. The 2015 Plan was terminated as to new grant awards in June 2019.

The 2019 Plan provides for the issuance of shares of common stock for incentive stock options, non-statutory stock options, restricted stock awards, restricted stock unit awards and other stock awards to its employees, members of its board of directors and consultants. In general, the stock options issued under the 2019 Plan expire ten years from the date of grant and vest over a four-year period. Certain stock option grants vest based on the achievement of

development or regulatory milestones. The 2019 Plan allows for the early exercise of all stock option grants if authorized by the board of directors at the time of grant.

In February 2021, the Company’s board of directors adopted the 2021 Employment Inducement Incentive Award Plan (the “Inducement Plan”). The Inducement Plan is a non-shareholder approved stock plan adopted pursuant to the “inducement exception” provided under Nasdaq listing rules. The Inducement Plan is used exclusively for the issuance of non-statutory stock options to certain new hires who satisfy the requirements to be granted inducement grants under Nasdaq rules as an inducement material to the individual’s entry into employment with the Company. The terms of the Inducement Plan are substantially similar to the terms of the 2019 Plan. As amended in May 2021 and December 2021, the Company has reserved 2,800,000 shares for the issuance of common stock under the Inducement Plan.

A summary of the Company’s stock option activity under the 2015 Plan, 2019 Plan and Inducement Plan is as follows:


	Number of Options			Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Term (in years)		Aggregate Intrinsic Value
Outstanding at December 31, 2021		6,444,744		$	5.28
Granted		2,790,518		$	1.62
Cancelled		(719,566	)	$	4.26
Outstanding at December 31, 2022		8,515,696		$	4.16		8.1	$	101,611
Options vested and expected to vest at December 31, 2022		8,515,696		$	4.16		8.1	$	101,611
Vested and exercisable at December 31, 2022		3,437,688		$	4.88		7.1	$	82,077

The weighted average grant date fair value per share of option grants for the years ended December 31, 2022 and 2021 was $1.29 and $4.35 per share, respectively. The intrinsic value is calculated as the difference between the fair value of the Company’s common stock at December 31, 2022 of the option exercise and the exercise price of that stock option. The aggregate intrinsic value of stock options exercised during the years ended December 31, 2022 and 2021 was zero and $0.4 million.

Restricted Stock Unit Awards

Restricted stock unit awards (“RSUs”) are rights to receive shares of the Company’s common stock upon satisfaction of specific vesting conditions. The Company began issuing RSUs in the first quarter of 2022. The RSUs generally vest over an 18 month to two-year period. RSUs activity under the 2019 Plan is summarized as follows:



	Number of Restricted Stock Units			Weighted-Average Remaining Contractual Term (in years)		Weighted-Average Grant Date Fair Value
Nonvested at December 31, 2021		—
Granted		1,056,507				$	1.65
Vested		(6,494	)			$	2.43
Forfeited/ Repurchased		(40,930	)			$	1.79
Nonvested at December 31, 2022		1,009,083			0.6	$	1.64
Units expected to vest as of December 31, 2022		1,009,083			0.6	$	1.64

The total fair value of shares vested during the year ended December 31, 2022 was nominal.

Stock-Based Compensation Expense

The weighted-average assumptions used in the Black-Scholes option pricing model to determine the fair value of stock option grants were as follows:


	Years Ended December 31,
	2022			2021
Risk-free interest rate		2.2	%		0.9	%
Expected volatility		100.5	%		92.8	%
Expected term (in years)		6.1			6.2
Expected dividend yield		—	%		—	%

Expected volatility. The expected volatility assumption is based on volatilities of a peer group of similar companies whose share prices are publicly available. The peer group was developed based on companies in the life sciences industry with comparable characteristics to the Company including enterprise value, risk profiles, position within the industry, and with historical share price information sufficient to meet the expected life of the stock-based awards. The Company will continue to apply this process until a sufficient amount of historical information regarding the volatility of its own stock price becomes available.

Expected term. The expected term represents the period of time that options are expected to be outstanding. Due to limited historical exercise behavior, it determined the expected life assumption using the simplified method for employees, which is an average of the contractual term of the option and its vesting period. The expected term for nonemployee options is generally the remaining contractual term.

Risk-free interest rate. The risk-free interest rate is based on the implied yield on the U.S. Treasury securities with a maturity date similar to the expected term of the associated stock option award.

Expected dividend yield. The Company bases the expected dividend yield assumption on the fact that it has never paid cash dividends and has no present intention to pay cash dividends and, therefore, used an expected dividend yield of zero.

RSUs represent rights to receive shares of common stock contingent upon satisfaction of specific vesting conditions. The stock-based compensation expense for these awards was determined using the closing price on the grant date applied to the total number of shares that were anticipated to fully vest.

Stock-based compensation expense recognized for all equity awards has been reported in the statements of operations as follows (in thousands):


	Years Ended December 31,
	2022		2021
Research and development	$	4,055	$	3,136
General and administrative		3,376		2,739
	$	7,431	$	5,875

As of December 31, 2022, the unrecognized compensation cost related to non-vested stock options was $12.6 million, which is expected to be recognized over a weighted-average period of 2.6 years.

As of December 31, 2022, the unrecognized compensation cost related to non-vested restricted stock units was $1.0 million, which is expected to be recognized over a weighted-average period of 1.0 year.

Common Stock Reserved for Future Issuance

Common stock reserved for future issuance is as follows (in thousands):


	December 31,
	2022		2021
Common stock warrants		3,411		4,235
Common stock options outstanding		8,516		6,445
Restricted stock unit awards unvested and outstanding		1,009		—
Common stock available for issuance under Inducement Plan and 2019 Plan		1,230		1,842
		14,166		12,522

- Definition

The entire disclosure for shareholders' equity comprised of portions attributable to the parent entity and noncontrolling interest, including other comprehensive income. Includes, but is not limited to, balances of common stock, preferred stock, additional paid-in capital, other capital and retained earnings, accumulated balance for each classification of other comprehensive income and amount of comprehensive income.

+ References

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+ Details

COVID-19 Pandemic and CARES Act

12 Months Ended

Dec. 31, 2022

C O V I D19 Pandemic And C A R E S Act [Abstract]

COVID-19 Pandemic and CARES Act

The COVID-19 pandemic has presented substantial public health and economic challenges and continues to affect economies, financial markets and business operations around the world. The pandemic may continue to directly or indirectly affect the timeline for the Company’s preclinical and manufacturing activities, planned regulatory submissions and clinical trials, including the Company’s global Phase 3 Study ZILO-301. The Company considered the impacts of COVID-19 on the assumptions and estimates used to prepare its consolidated financial statements and determined that there were no material adverse impacts on the Company’s results of operations and financial position at December 31, 2022. The full extent to which the COVID-19 pandemic will continue to directly or indirectly impact the Company’s business results of operations and financial condition, will depend on future developments that are highly uncertain, including as a result of new information that may emerge concerning COVID-19 and the actions taken to contain or treat it, the success or failure of ongoing vaccination programs, the emergence and spread of additional variants of COVID-19, as well as the economic impact on local, regional, national and international markets.

In response to the COVID-19 pandemic, the CARES Act was signed into law on March 27, 2020. The CARES Act, among other things, includes tax provisions relating to refundable payroll tax credits, deferment of employer’s social security payments, net operating loss utilization and carryback periods, modifications to the net interest deduction limitations and technical corrections to tax depreciation methods for qualified improvement property, and authorized the Paycheck Protection Program. The Company continues to monitor changes and revisions to the CARES Act and its impact on the Company’s consolidated financial position, results of operations and cash flows.

Income Taxes

12 Months Ended

Dec. 31, 2022

Income Tax Disclosure [Abstract]

Income Taxes

A reconciliation of the Company’s effective tax rate and federal statutory tax rate is as follows (in thousands):


	Years Ended December 31,
	2022			2021
Federal income taxes	$	(9,276	)	$	(6,579	)
State income taxes, net of federal benefit		(2,820	)		(2,013	)
Permanent items		3			4
Stock based compensation		831			512
Research and development credit carryforwards		(4,747	)		(1,099	)
Other, net		(48	)		(131	)
Change in valuation allowance		16,057			9,306
Provision for income taxes	$	—		$	—

Significant components of the Company’s net deferred tax assets are as follows (in thousands):


	December 31,
	2022			2021
Deferred tax assets:
Net operating loss carryforwards	$	27,889		$	21,254
Research and development credit carryforwards		7,804			3,051
Accrued expenses		860			484
Capitalized research and development costs		19,153			15,847
Stock based compensation		2,188			1,206
Other, net		29			24
Total deferred tax assets		57,923			41,866
Valuation allowance		(57,899	)		(41,845	)
		24			21
Deferred tax liabilities:
Right of use asset		(24	)		(21	)
Total deferred tax liabilities		(24	)		(21	)
Net deferred tax assets	$	—		$	—

As of December 31, 2022 and 2021, management assessed the realizability of deferred tax assets and evaluated the need for a valuation allowance for deferred tax assets on a jurisdictional basis. This evaluation utilizes the framework contained in ASC 740, Income Taxes, wherein management analyzes all positive and negative evidence available at the balance sheet date to determine whether all or some portion of the Company's deferred tax assets will not be realized. Under this guidance, a valuation allowance must be established for deferred tax assets when it is more-likely-than-not that the asset will not be realized. In assessing the realization of the Company's deferred tax assets, management considers all available evidence, both positive and negative.

In concluding on the evaluation, management placed significant emphasis on guidance in ASC 740, which states that “a cumulative loss in recent years is a significant piece of negative evidence that is difficult to overcome.” Based upon available evidence, it was concluded on a more-likely-than-not basis that all deferred tax assets were not realizable as of December 31, 2022. Accordingly, a valuation allowance of $58.0 million has been recorded to offset this deferred tax asset. The valuation allowance increased by $16.1 million and $9.3 million for the years ended December 31, 2022 and 2021, respectively.

At December 31, 2022, the Company had federal and state net operating loss (NOL) carryforwards of approximately $99.1 million and $101.6 million, respectively. Of the federal and state net operating losses at December 31, 2022, $72.8 million and $0.2 million, respectively, do not expire, and the remaining federal and state net operating loss carryforwards will begin expiring in 2033 and 2029, respectively, unless previously utilized. At December 31, 2022, the Company also had federal and state research and development credit carryforwards of approximately $2.9 million and $2.2 million, respectively. The federal research and development credit carryforwards will begin expiring in 2034 unless previously utilized. The state research and development credits do not expire.

Pursuant to Internal Revenue Code Sections 382 and 383, annual use of the Company’s net operating loss and research and development tax credit carryforwards may be limited in the event a cumulative change in ownership of more than 50% occurs within a three-year period. The Company has not completed a Section 382 study to assess whether an ownership change has occurred or whether there have been multiple ownership changes since the Company’s formation due to the complexity and cost associated with such a study and the fact that there may be additional such ownership changes in the future. If eliminated, the related asset would be removed from the deferred tax asset schedule with a corresponding reduction in the valuation allowance. Due to the existence of the valuation allowance, limitations created by future ownership changes, if any, will not impact the Company’s effective tax rate.

The Company recognizes a tax benefit from an uncertain tax position when it is more likely than not that the position will be sustained upon examination, including resolutions of any related appeals or litigation processes, based on the technical merits. Income tax positions must meet a more likely than not recognition at the effective date to be recognized. At December 31, 2022 and 2021, there were no unrecognized tax benefits recorded in the

consolidated financial statements. The Company does not expect any material changes to unrecognized tax benefits within the next twelve months.

The Company is subject to taxation in the United States federal and state jurisdictions. The Company’s 2014 through 2022 federal income tax and state income tax returns are subject to examination by federal and state tax authorities due to the carryforward of unutilized net operating losses and research and development credits. The Company is not currently under examination by any tax authority.

The Company’s policy is to recognize interest and penalties related to income tax matters in income tax expense. The Company has not recognized interest or penalties in its consolidated statements of operations since inception.

- Definition

The entire disclosure for income taxes. Disclosures may include net deferred tax liability or asset recognized in an enterprise's statement of financial position, net change during the year in the total valuation allowance, approximate tax effect of each type of temporary difference and carryforward that gives rise to a significant portion of deferred tax liabilities and deferred tax assets, utilization of a tax carryback, and tax uncertainties information.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
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-URI https://asc.fasb.org/extlink&oid=120395691&loc=d3e23780-122690

+ Details

Description of Business, Basis of Presentation and Summary of Significant Accounting Policies (Policies)

12 Months Ended

Dec. 31, 2022

Accounting Policies [Abstract]

Principles of Consolidation

Going Concern

Use of Estimates

Cash and Cash Equivalents

Short-term Investments

Concentration of Credit Risk

Patent Costs

Costs related to filing and pursuing patent applications are recorded as general and administrative expense and expensed as incurred since recoverability of such expenditures is uncertain.

Research and Development Expenses and Accruals

Fair Value Measurements

Revenue Recognition

Stock-Based Compensation

Income Taxes

Segment Reporting

Net Loss Per Share


	December 31,
	2022		2021
Warrants to purchase common stock		3,411		4,235
Common stock options		8,516		6,445
Restricted stock units		1,009		—
		12,936		10,680

Recently Accounting Pronouncements

Recently Adopted Accounting Pronouncements

Accounting Standards Not Yet Adopted

Description of Business, Basis of Presentation and Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2022

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Schedule of Potentially Dilutive Securities Excluded from Calculation of Diluted Net Loss per Share Would Be Anti-dilutive


	December 31,
	2022		2021
Warrants to purchase common stock		3,411		4,235
Common stock options		8,516		6,445
Restricted stock units		1,009		—
		12,936		10,680

Balance Sheet Details (Tables)

12 Months Ended

Dec. 31, 2022

Payables and Accruals [Abstract]

Schedule of Prepaid and Other

Prepaid and other consist of the following (in thousands):


	December 31,		December 31,
	2022		2021
Research and development	$	—	$	294
Clinical trials		2,616		—
Insurance		669		765
Other prepaid expenses		103		85
Related party receivable (see Note 4)		—		359
Grant and other receivable		178		585
	$	3,566	$	2,088

Summary of Accrued Liabilities

Accrued liabilities consist of the following (in thousands):


	December 31,		December 31,
	2022		2021
Research and development	$	972	$	779
Clinical trials		868		518
Legal fees		138		154
Compensation		2,691		1,955
Other		9		25
	$	4,678	$	3,431

Marketable Securities (Tables)

12 Months Ended

Dec. 31, 2022

Investments, Debt and Equity Securities [Abstract]

Schedule of Short-term Investments and are Measured at a Fair Value on a Recurring Basis



	Maturity (in years)	Amortized Cost		Unrealized Gains		Unrealized Losses		Fair Market Value
Cash and cash equivalents:
Money market funds	1 or less	$	25,108	$	—	$	—	$	25,108
U.S. Treasury debt securities	1 or less		1,996		—		—		1,996
U.S. Government Agency	1 or less		1,991		—		—		1,991
Total cash and cash equivalents		$	29,095	$	—	$	—	$	29,095
Short term investments:
U.S. Treasury debt securities	1 or less	$	21,681	$	7	$	—	$	21,688
Commercial Paper	1 or less		2,936		—		—		2,936
U.S. Government Agency	1 or less		1,956		2		—		1,958
Total short-term investments		$	26,573	$	9	$	—	$	26,582

Total marketable securities		$	55,668	$	9	$	—	$	55,677

Fair Value (Tables)

12 Months Ended

Dec. 31, 2022

Fair Value Disclosures [Abstract]

Schedule of Companys Assets Measured at Fair Value on Recurring Basis

As of December 31, 2022, the following fair value hierarchy table presents the Company’s financial assets measured at fair value on a recurring basis (in thousands):


	Total		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
As of December 31, 2022
Assets:
Cash and cash equivalents:
Money market funds	$	25,108	$	25,108	$	—	$	—
U.S. Treasury debt securities		1,996		1,996		—		—
U.S. Government Agency		1,991		—		1,991		—
Total cash and cash equivalents	$	29,095	$	27,104	$	1,991	$	—
Short term investments:
U.S. Treasury debt securities	$	21,688	$	21,688	$	—	$	—
Commercial Paper		2,936		—		2,936		—
U.S. Government Agency		1,958		—		1,958		—
Total short-term investments	$	26,582	$	21,688	$	4,894	$	—

Total assets measured at fair value	$	55,677	$	48,792	$	6,885	$	—

Stockholders' Equity (Tables)

12 Months Ended

Dec. 31, 2022

Summary Of Warrant Activity And Changes In Warrants Outstanding

A summary of warrant activity and changes in warrants outstanding is presented below:


	Number of Shares Underlying Warrants			Weighted-Average Exercise Price per Share		Weighted-Average Remaining Contractual Term
Balance Outstanding - December 31, 2020		5,031,841		$	9.25		4.40
Exercised		(796,931	)		2.56		—
Balance Outstanding - December 31, 2021		4,234,910			10.50		3.31
Expired		(824,268	)		38.64		—
Balance Outstanding - December 31, 2022		3,410,642		$	3.70		2.94

Summary of Stock Option Activity

A summary of the Company’s stock option activity under the 2015 Plan, 2019 Plan and Inducement Plan is as follows:


	Number of Options			Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Term (in years)		Aggregate Intrinsic Value
Outstanding at December 31, 2021		6,444,744		$	5.28
Granted		2,790,518		$	1.62
Cancelled		(719,566	)	$	4.26
Outstanding at December 31, 2022		8,515,696		$	4.16		8.1	$	101,611
Options vested and expected to vest at December 31, 2022		8,515,696		$	4.16		8.1	$	101,611
Vested and exercisable at December 31, 2022		3,437,688		$	4.88		7.1	$	82,077

Summary of Restricted Stock Unit Activity

RSUs activity under the 2019 Plan is summarized as follows:



	Number of Restricted Stock Units			Weighted-Average Remaining Contractual Term (in years)		Weighted-Average Grant Date Fair Value
Nonvested at December 31, 2021		—
Granted		1,056,507				$	1.65
Vested		(6,494	)			$	2.43
Forfeited/ Repurchased		(40,930	)			$	1.79
Nonvested at December 31, 2022		1,009,083			0.6	$	1.64
Units expected to vest as of December 31, 2022		1,009,083			0.6	$	1.64

The total fair value of shares vested during the year ended December 31, 2022 was nominal.

Summary of Share-Based Compensation Expense

Stock-based compensation expense recognized for all equity awards has been reported in the statements of operations as follows (in thousands):


	Years Ended December 31,
	2022		2021
Research and development	$	4,055	$	3,136
General and administrative		3,376		2,739
	$	7,431	$	5,875

Common Stock Reserved for Future Issuance

Common stock reserved for future issuance is as follows (in thousands):


	December 31,
	2022		2021
Common stock warrants		3,411		4,235
Common stock options outstanding		8,516		6,445
Restricted stock unit awards unvested and outstanding		1,009		—
Common stock available for issuance under Inducement Plan and 2019 Plan		1,230		1,842
		14,166		12,522

Stock Option Grants

Schedule of Assumptions Used to Determine Fair Value

The weighted-average assumptions used in the Black-Scholes option pricing model to determine the fair value of stock option grants were as follows:


	Years Ended December 31,
	2022			2021
Risk-free interest rate		2.2	%		0.9	%
Expected volatility		100.5	%		92.8	%
Expected term (in years)		6.1			6.2
Expected dividend yield		—	%		—	%

- Definition

Tabular disclosure of an entity's stock, including par or stated value per share, number and dollar amount of share subscriptions, shares authorized, shares issued, shares outstanding, number and dollar amount of shares held in an employee trust, dividend per share, total dividends, share conversion features, par value plus additional paid in capital, the value of treasury stock and other information necessary to a fair presentation, and EPS information. Stock by class includes common, convertible, and preferred stocks which are not redeemable or redeemable solely at the option of the issuer. Includes preferred stock with redemption features that are solely within the control of the issuer and mandatorily redeemable stock if redemption is required to occur only upon liquidation or termination of the reporting entity. If more than one issue is outstanding, state the title of each issue and the corresponding dollar amount; dollar amount of any shares subscribed but unissued and the deduction of subscriptions receivable there from; number of shares authorized, issued, and outstanding.

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+ Details

Income Taxes (Tables)

12 Months Ended

Dec. 31, 2022

Income Tax Disclosure [Abstract]

Summary of Reconciliation of Effective Tax Rate and Federal Statutory Tax Rate

A reconciliation of the Company’s effective tax rate and federal statutory tax rate is as follows (in thousands):


	Years Ended December 31,
	2022			2021
Federal income taxes	$	(9,276	)	$	(6,579	)
State income taxes, net of federal benefit		(2,820	)		(2,013	)
Permanent items		3			4
Stock based compensation		831			512
Research and development credit carryforwards		(4,747	)		(1,099	)
Other, net		(48	)		(131	)
Change in valuation allowance		16,057			9,306
Provision for income taxes	$	—		$	—

Summary of Significant Components of Net Deferred Tax Assets

Significant components of the Company’s net deferred tax assets are as follows (in thousands):


	December 31,
	2022			2021
Deferred tax assets:
Net operating loss carryforwards	$	27,889		$	21,254
Research and development credit carryforwards		7,804			3,051
Accrued expenses		860			484
Capitalized research and development costs		19,153			15,847
Stock based compensation		2,188			1,206
Other, net		29			24
Total deferred tax assets		57,923			41,866
Valuation allowance		(57,899	)		(41,845	)
		24			21
Deferred tax liabilities:
Right of use asset		(24	)		(21	)
Total deferred tax liabilities		(24	)		(21	)
Net deferred tax assets	$	—		$	—

Description of Business, Basis of Presentation and Summary of Significant Accounting Policies - Additional Information (Details) $ in Thousands	1 Months Ended	12 Months Ended
	Dec. 31, 2022 USD ($) shares	Dec. 31, 2022 USD ($) Segment shares	Dec. 31, 2021 USD ($) shares
Description Of Business Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Accumulated deficit	$ (158,300)	$ (158,300)	$ (114,130)
Cash, cash equivalents, and short-term investments	63,700	63,700
Clinical trials	$ 868	868	518
Research and development		$ 32,980	$ 24,086
Number of operating segments \| Segment		1
Weighted-average shares subject to repurchase \| shares		0	7,000
Common Stock \| ATM Program
Description Of Business Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Common stock shares issued \| shares		40,000,000.0
Number of shares sold \| shares	8,031,355	8,031,355	0
Net proceeds from sale of shares		$ 9,600	$ 0

Description of Business, Basis of Presentation and Summary of Significant Accounting Policies - Schedule of Potentially Dilutive Securities Excluded from Calculation of Diluted Net Loss per Share Would Be Anti-dilutive (Detail) - shares shares in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potentially dilutive securities	12,936	10,680
Warrants to purchase common stock
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potentially dilutive securities	3,411	4,235
Common Stock Options
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potentially dilutive securities	8,516	6,445
Restricted Stock Unit
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potentially dilutive securities	1,009	0

Balance Sheet Details - Prepaid and Other (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Prepaid Expense, Current [Abstract]
Research and development	$ 0	$ 294
Clinical trials	2,616	0
Insurance	669	765
Other prepaid expenses	103	85
Related party receivable	0	359
Grant and other receivable	178	585
Prepaid and other expense total	$ 3,566	$ 2,088

Balance Sheet Details - Accrued Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Payables and Accruals [Abstract]
Research and development	$ 972	$ 779
Clinical trials	868	518
Legal fees	138	154
Compensation	2,691	1,955
Other	9	25
Total accrued liabilities	$ 4,678	$ 3,431

Marketable Securities - Additional Information (Details) - USD ($)	Dec. 31, 2022	Dec. 31, 2021
Short-Term Investments
Available-for-sale debt securities	$ 55,677,000
Cash Equivalents
Short-Term Investments
Available-for-sale debt securities	$ 37,100,000	$ 90,800

Marketable Securities - Schedule of Short-term Investments and are Measured at a Fair Value on a Recurring Basis (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2022 USD ($)
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost	$ 55,668
Unrealized Gains	9
Unrealized Losses	0
Fair Market Value	55,677
Cash and cash equivalents
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost	29,095
Unrealized Gains	0
Unrealized Losses	0
Fair Market Value	29,095
Short term investments
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost	26,573
Unrealized Gains	9
Unrealized Losses	0
Fair Market Value	26,582
Money market funds \| Cash and cash equivalents
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost	25,108
Unrealized Gains	0
Unrealized Losses	0
Fair Market Value	$ 25,108
Money market funds \| Cash and cash equivalents \| Maximum
Debt Securities, Available-for-Sale [Line Items]
Maturity (in years)	1 year
U.S. Treasury debt securities \| Cash and cash equivalents
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost	$ 1,996
Unrealized Gains	0
Unrealized Losses	0
Fair Market Value	$ 1,996
U.S. Treasury debt securities \| Cash and cash equivalents \| Maximum
Debt Securities, Available-for-Sale [Line Items]
Maturity (in years)	1 year
U.S. Treasury debt securities \| Short term investments
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost	$ 21,681
Unrealized Gains	7
Unrealized Losses	0
Fair Market Value	$ 21,688
U.S. Treasury debt securities \| Short term investments \| Maximum
Debt Securities, Available-for-Sale [Line Items]
Maturity (in years)	1 year
Commercial Paper \| Short term investments
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost	$ 2,936
Unrealized Gains	0
Unrealized Losses	0
Fair Market Value	$ 2,936
Commercial Paper \| Short term investments \| Maximum
Debt Securities, Available-for-Sale [Line Items]
Maturity (in years)	1 year
U.S. Government Agency \| Cash and cash equivalents
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost	$ 1,991
Unrealized Gains	0
Unrealized Losses	0
Fair Market Value	$ 1,991
U.S. Government Agency \| Cash and cash equivalents \| Maximum
Debt Securities, Available-for-Sale [Line Items]
Maturity (in years)	1 year
U.S. Government Agency \| Short term investments
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost	$ 1,956
Unrealized Gains	2
Unrealized Losses	0
Fair Market Value	$ 1,958
U.S. Government Agency \| Short term investments \| Maximum
Debt Securities, Available-for-Sale [Line Items]
Maturity (in years)	1 year

Commitments, Contingencies and Related Party Transactions - Additional Information (Details) - USD ($) $ in Thousands		12 Months Ended
	Apr. 18, 2022	Dec. 31, 2022	Dec. 31, 2021
Commitments And Contingencies [Line Items]
Amounts receivable		$ 0	$ 359
Shanghai Pharmaceutical (USA) Inc.
Commitments And Contingencies [Line Items]
Amounts receivable		0	400
San Diego, California \| Office Space
Commitments And Contingencies [Line Items]
Rent expense		$ 200	$ 200
Annual base rent	$ 157,000
Lease discount rate		10.00%
Operating lease liability		$ 87,000
Weighted average remaining lease term		7 months 6 days

License, Collaboration, Grants, Research Subaward Agreement and CVR Agreements (Details) - USD ($)		1 Months Ended					12 Months Ended
	Nov. 01, 2021	Jan. 31, 2022	Aug. 31, 2021	Oct. 31, 2017	Aug. 31, 2017	May 31, 2016	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2017	Dec. 31, 2015	Sep. 30, 2021	Jul. 31, 2020	Dec. 31, 2014
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Research and development expense							$ 0	$ 0
Patent costs as general and administrative expense							13,457,000	11,595,000
Grant revenue							1,490,000	4,315,000
The National Institute of Health (“NIH”) Grant Awards
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Grants awarded to researchers			$ 2,200,000
Grant revenue							1,200,000
Payable to subawardees			$ 700,000
Award payments received							1,100,000	100,000
Unbilled grant receivable							100,000	100,000
Georgetown University
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Annual license maintenance fee to be paid and payment made										$ 10,000
MD Anderson Cancer Center
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Research and development expense							$ 500,000	100,000
Aggregate cost											$ 800,000	$ 800,000
Regents of the University of California
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Written notice of termination, period							60 days
Research and development expense							$ 25,000	25,000
Upfront license fees paid						$ 500,000
Common stock shares issued						107,108,000
Annual license maintenance fees									$ 25,000
Worldwide sales milestones based on achievement of tiered revenue levels						$ 75,000,000.0
Patent costs as general and administrative expense							$ 100,000	300,000
Regents of the University of California \| The National Institute of Health (“NIH”) Grant Awards
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Research agreement term							5 years
University of California San Diego School of Medicine \| The California Institute for Regenerative Medicine ("CIRM") Award
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Grants awarded to researchers				$ 5,800,000	$ 18,300,000
Development milestones to be received under research subaward agreements throughout award project period					$ 14,500,000
Subaward payments received							$ 700,000	2,200,000
Grant revenue							400,000	4,200,000
Related qualifying subaward costs							$ 500,000	8,800,000
Exclusive License Agreement \| Georgetown University
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Written notice of termination, period							90 days
Days after receipt of notice, to pay failure amount							30 days
Days after receipt of notice for default in payment							60 days
Minimum period in days of written notice to terminate license agreement							60 days
Collaborative Arrangement \| MD Anderson Cancer Center
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Potential regulatory milestone payments													$ 1,000,000.0
Research Agreement 2022 \| Regents of the University of California \| The National Institute of Health (“NIH”) Grant Awards
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Research agreement term		4 years
Research amount received		$ 1,600,000
Research amount payable quarterly		125,000					$ 3,600,000	300,000
Other research and development expense							500,000
Research Agreement 2023 \| Regents of the University of California \| The National Institute of Health (“NIH”) Grant Awards
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Research amount payable quarterly		131,250
Research Agreement 2024 \| Regents of the University of California \| The National Institute of Health (“NIH”) Grant Awards
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Research amount payable quarterly		$ 137,813
License Agreement \| University of Tennessee Research Foundation
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Research and development expense							$ 300,000	$ 100,000
CVR Agreement
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Percentage of net sales	5.00%
Period from closing during which payment of percentage of net proceeds would be payable under the CVR	15 years
Period from closing during which the grant, sale or transfer of rights to the Company's SARD or SARM technology could trigger a payment under the CVR Agreement	10 years
Maximum \| The California Institute for Regenerative Medicine ("CIRM") Award
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Amount agreed to be provided in contingency funds				$ 1,000,000.0
Maximum \| Regents of the University of California
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Potential regulatory milestone payments						24,500,000
Maximum \| Exclusive License Agreement \| Georgetown University
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Potential milestone payments										$ 200,000
Minimum [Member] \| Regents of the University of California
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Potential regulatory milestone payments						20,100,000
Advance licensed assets						$ 1,000,000.0

Fair Value - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Current financial assets or liabilities measured at fair value on a recurring basis		$ 0
Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Transfers into or out of Level 3	$ 0	$ 0

Stockholders' Equity - Amended and Restated Articles of Incorporation (Details) - $ / shares	Dec. 31, 2022	Dec. 31, 2021	May 25, 2021
Equity [Abstract]
Common stock, shares authorized	120,000,000	60,000,000	120,000,000
Preferred stock, shares authorized	5,000,000	5,000,000	5,000,000
Preferred stock, par value	$ 0.001	$ 0.001	$ 0.001

Stockholders' Equity - ATM Program (Details) - ATM Program - Common Stock - USD ($) $ in Millions	1 Months Ended		12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2022	Dec. 31, 2021
Subsidiary, Sale of Stock [Line Items]
Number of shares sold	8,031,355		8,031,355	0
Net proceeds from sale of shares			$ 9.6	$ 0.0
Aggregate offering price		$ 50.0

Stockholders' Equity - Summary Of Warrant Activity And Changes In Warrants Outstanding (Details) - $ / shares	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Equity [Abstract]
Options outstanding, Number of Warrant	4,234,910,000	5,031,841,000
Number of Shares Underlying Warrants Exercised		(796,931,000)
Number of Shares Underlying Warrants Expired	(824,268,000)
Options outstanding, Number of Warrant	3,410,642,000	4,234,910,000	5,031,841,000
Weighted-Average Exercise Price	$ 10.50	$ 9.25
Exercised		2.56
Expired	38.64
Weighted-Average Exercise Price	$ 3.70	$ 10.50	$ 9.25
Weighted-Average Remaining Contractual Term	2 years 11 months 8 days	3 years 3 months 21 days	4 years 4 months 24 days

Stockholders' Equity - Equity Incentive Plans (Details) - USD ($) $ / shares in Units, $ in Millions	1 Months Ended	12 Months Ended
	Jul. 31, 2015	Dec. 31, 2022	Dec. 31, 2021	May 25, 2021
Class Of Stock [Line Items]
Percentage of annual increase in shares reserved for issuance		5.00%
Number of common stock shares provided for issuance of stock awards to its employees		14,166,000	12,522,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Intrinsic Value		$ 0.0	$ 0.4
2019 incentive award plan
Class Of Stock [Line Items]
Shares of common stock reserved for issuance		1,954,150
2019 incentive award plan and inducement plan
Class Of Stock [Line Items]
Number of common stock shares provided for issuance of stock awards to its employees				2,800,000
2015 plan
Class Of Stock [Line Items]
Options expiration term	10 years
Options vesting period	4 years
2019 and 2015 plan
Class Of Stock [Line Items]
Weighted average grant date fair value per share of option grants		$ 1.29	$ 4.35
2019 plan
Class Of Stock [Line Items]
Options expiration term	10 years
Options vesting period	4 years

Stockholders' Equity - Summary of Stock Option Activity (Details) - Equity incentive plan $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2022 USD ($) $ / shares shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of options, beginning balance \| shares	6,444,744,000
Number of options, granted \| shares	2,790,518,000
Number of options, cancelled \| shares	(719,566,000)
Number of options, ending balance \| shares	8,515,696,000
Number of options vested and expected to vest \| shares	8,515,696,000
Number of options, vested and exercisable \| shares	3,437,688,000
Weighted average exercise price, beginning balance \| $ / shares	$ 5.28
Weighted average exercise price, granted \| $ / shares	1.62
Weighted average exercise price, cancelled \| $ / shares	4.26
Weighted average exercise price, exercised \| $ / shares	4.16
Weighted average exercise price, options vested and expected to vest \| $ / shares	4.16
Weighted average exercise price, vested and exercisable \| $ / shares	$ 4.88
Weighted average contractual term outstanding, ending balance	8 years 1 month 6 days
Weighted-average remaining contractual term, Options vested and expected to vest	8 years 1 month 6 days
Remaining weighted-average period, vested and exercisable	7 years 1 month 6 days
Options outstanding, Aggregate Intrinsic Value \| $	$ 101,611
Aggregate intrinsic value, options vested and expected to vest \| $	101,611
Vested and exercisable, Aggregate intrinsic value \| $	$ 82,077

Stockholders' Equity - Summary of Restricted Stock Unit Activity (Details) - Restricted Stock Unit shares in Thousands	12 Months Ended
	Dec. 31, 2022 $ / shares shares
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Number of restricted stock units, Granted \| shares	1,056,507
Number of restricted stock units, Vested \| shares	(6,494)
Number of restricted stock units, Forfeited/Repurchased \| shares	(40,930)
Number of restricted stock units, Ending balance \| shares	1,009,083
Number of restricted units expected to vest \| shares	1,009,083
Weighted-average remaining contractual term nonvested	7 months 6 days
Weighted-average remaining contractual term, Options vested and expected to vest	7 months 6 days
Weighted average exercise price, granted \| $ / shares	$ 1.65
Weighted average exercise price, Vested \| $ / shares	2.43
Weighted average exercise price, Forfeited/ Repurchased \| $ / shares	1.79
Weighted-average grant date fair value nonvested \| $ / shares	1.64
Weighted average exercise price, options vested and expected to vest \| $ / shares	$ 1.64

Stockholders' Equity - Schedule of Assumptions Used to Estimate Fair Value of Stock Option Grants (Details)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Share-Based Payment Arrangement [Abstract]
Risk-free interest rate	2.20%	0.90%
Expected volatility	100.50%	92.80%
Expected term (in years)	6 years 1 month 6 days	6 years 2 months 12 days

Stockholders' Equity - Share-Based Compensation Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 7,431	$ 5,875
Research and development
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	4,055	3,136
General and administrative
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 3,376	$ 2,739

Stockholders' Equity - Stock-Based Compensation Expense (Details)	12 Months Ended
	Dec. 31, 2022 USD ($)
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Unrecognized compensation cost related to non-vested stock option	$ 12,600,000
Remaining weighted-average period	2 years 7 months 6 days
Restricted Stock Unit
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Unrecognized compensation cost related to non-vested stock option	$ 1,000.0
Remaining weighted-average period	1 year

Stockholders' Equity - Common Stock Reserved for Future Issuance (Details) - shares shares in Thousands	Dec. 31, 2022	Dec. 31, 2021
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock warrants	3,411	4,235
Common stock options outstanding	8,516	6,445
Restricted stock unit awards unvested and outstanding	1,009
Common stock available for future issuance	14,166	12,522
Inducement Plan and 2019 Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock available for future issuance	1,230	1,842

Income Taxes - Summary of Reconciliation of Effective Tax Rate and Federal Statutory Tax Rate (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Income Tax Disclosure [Abstract]
Federal income taxes	$ (9,276)	$ (6,579)
State income taxes, net of federal benefit	(2,820)	(2,013)
Permanent items	3	4
Stock based compensation	831	512
Research and development credit carryforwards	(4,747)	(1,099)
Other, net	(48)	(131)
Change in valuation allowance	16,057	9,306
Provision for income taxes	$ 0	$ 0

- Definition

Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

+ References + Details

Income Taxes - Summary of Significant Components of Net Deferred Tax Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Deferred tax assets:
Net operating loss carryforwards	$ 27,889	$ 21,254
Research and development credit carryforwards	7,804	3,051
Accrued expenses	860	484
Capitalized research and development costs	19,153	15,847
Stock based compensation	2,188	1,206
Other, net	29	24
Total deferred tax assets	57,923	41,866
Valuation allowance	(57,899)	(41,845)
Net deferred tax assets and liabilities	24	21
Deferred tax liabilities:
Right of use asset	(24)	(21)
Total deferred tax liabilities	$ (24)	$ (21)

Income Taxes - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Income Taxes [Line Items]
Deferred tax assets, fully offset by valuation allowance	$ 57,899,000	$ 41,845,000
Change In Valuation Allowance	16,100,000	9,300,000
Research and development credit carryforward	$ 7,804,000	3,051,000
Cumulative changes in ownership percentage	50.00%
Period for cumulative change in ownership	3 years
Unrecognized Tax Benefits	$ 0	$ 0
Interest and penalties	0
Federal
Income Taxes [Line Items]
Net operating loss carryforwards	99,100,000
Operating loss carryforwards non expire portion	$ 72,800,000
Operating loss carryforwards expiration year	2033
Research and development credit carryforward	$ 2,900,000
Research and development credit carryforward expiration year	2034
State
Income Taxes [Line Items]
Net operating loss carryforwards	$ 101,600,000
Operating loss carryforwards non expire portion	$ 200,000
Operating loss carryforwards expiration year	2029
Research and development credit carryforward	$ 2,200,000

Fair Value - Schedule of Companys Assets Measured at Fair Value on Recurring Basis (Details) - Fair Value Measurements Recurring $ in Thousands	Dec. 31, 2022 USD ($)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash and cash equivalents	$ 29,095
Total short-term investments	26,582
Total assets measured at fair value	55,677
U.S. Government Agency
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash and cash equivalents	1,991
Total short-term investments	1,958
Money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash and cash equivalents	25,108
U.S. Treasury debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash and cash equivalents	1,996
Total short-term investments	21,688
Commercial Paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total short-term investments	2,936
Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash and cash equivalents	27,104
Total short-term investments	21,688
Total assets measured at fair value	48,792
Quoted Prices in Active Markets for Identical Assets (Level 1) \| U.S. Government Agency
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash and cash equivalents
Total short-term investments	0
Quoted Prices in Active Markets for Identical Assets (Level 1) \| Money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash and cash equivalents	25,108
Quoted Prices in Active Markets for Identical Assets (Level 1) \| U.S. Treasury debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash and cash equivalents	1,996
Total short-term investments	21,688
Quoted Prices in Active Markets for Identical Assets (Level 1) \| Commercial Paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total short-term investments	0
Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash and cash equivalents	1,991
Total short-term investments	4,894
Total assets measured at fair value	6,885
Significant Other Observable Inputs (Level 2) \| U.S. Government Agency
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash and cash equivalents	1,991
Total short-term investments	1,958
Significant Other Observable Inputs (Level 2) \| Money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash and cash equivalents
Significant Other Observable Inputs (Level 2) \| U.S. Treasury debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash and cash equivalents
Total short-term investments	0
Significant Other Observable Inputs (Level 2) \| Commercial Paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total short-term investments	2,936
Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash and cash equivalents
Total short-term investments
Total assets measured at fair value	0
Significant Unobservable Inputs (Level 3) \| U.S. Government Agency
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash and cash equivalents
Total short-term investments	0
Significant Unobservable Inputs (Level 3) \| Money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash and cash equivalents
Significant Unobservable Inputs (Level 3) \| U.S. Treasury debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash and cash equivalents
Total short-term investments	0
Significant Unobservable Inputs (Level 3) \| Commercial Paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total short-term investments	$ 0