Viridian Therapeutics (VRDN) 10-Q 13 May 22 2022 Q1 Quarterly report Financial data

Cover Page

Cover Page - shares	3 Months Ended
	Mar. 31, 2022	May 09, 2022
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2022
Document Transition Report	false
Entity File Number	001-36483
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	47-1187261
Entity Address, Address Line One	221 Crescent Street, Suite 401,
Entity Address, City or Town	Waltham
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	02453
City Area Code	617
Local Phone Number	272-4600
Title of 12(b) Security	Common Stock, $0.01 par value per share
Trading Symbol	VRDN
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding (in share)		27,927,423
Entity Central Index Key	0001590750
Amendment Flag	false
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	Q1
Current Fiscal Year End Date	--12-31
Entity Registrant Name	Viridian Therapeutics, Inc./DE

CONDENSED CONSOLIDATED BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Current assets:
Cash and cash equivalents	$ 30,858	$ 42,299
Short-term investments	144,570	154,666
Prepaid expenses and other current assets	3,439	2,747
Unbilled revenue - related party	522	451
Total current assets	179,389	200,163
Property and equipment, net	691	375
Operating lease right-of-use asset	1,543	1,680
Other assets	1,542	1,491
Total assets	183,165	203,709
Current liabilities:
Accounts payable	2,538	2,329
Accrued liabilities	11,560	11,018
Current portion of deferred revenue - related party	288	289
Total current liabilities	14,386	13,636
Deferred revenue - related party	1,077	1,149
Other liabilities	1,060	1,208
Total liabilities	16,523	15,993
Commitments and contingencies
Stockholders’ equity:
Common stock, $0.01 par value; 200,000,000 shares authorized; 27,169,422 and 23,924,004 shares issued and outstanding as of March 31, 2022 and December 31, 2021, respectively	272	239
Additional paid-in capital	439,187	412,101
Accumulated other comprehensive loss	(935)	(157)
Accumulated deficit	(383,993)	(358,300)
Total stockholders’ equity	166,642	187,716
Total liabilities and stockholders’ equity	183,165	203,709
Series A Preferred Stock (as converted to shares of common stock)
Stockholders’ equity:
Preferred stock	96,442	118,164
Series B Preferred Stock (as converted to shares of common stock)
Stockholders’ equity:
Preferred stock	$ 15,669	$ 15,669

CONDENSED CONSOLIDATED BALANC_2

CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Mar. 31, 2022	Dec. 31, 2021
Preferred stock, par value (in dollars per share)	$ 0.01
Preferred stock, shares authorized (in shares)	5,000,000
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	200,000,000	200,000,000
Common stock, shares issued (in shares)	27,169,422	27,169,422
Common stock, shares outstanding (in shares)	23,924,004	23,924,004
Series A Preferred Stock (as converted to shares of common stock)
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized (in shares)	435,000	435,000
Preferred stock, shares issued (in shares)	212,566	260,437
Preferred stock outstanding (in shares)	212,566	260,437
Series B Preferred Stock (as converted to shares of common stock)
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized (in shares)	500,000	500,000
Preferred stock, shares issued (in shares)	23,126	23,126
Preferred stock outstanding (in shares)	23,126	23,126

CONDENSED CONSOLIDATED STATEMEN

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Revenue:
Collaboration revenue - related party	$ 216	$ 1,451
Operating expenses:
Research and development	17,746	13,806
General and administrative	8,359	6,160
Total operating expenses	26,105	19,966
Loss from operations	(25,889)	(18,515)
Other income:
Interest and other income	196	55
Net loss	(25,693)	(18,460)
Change in unrealized loss on investments	(778)	(13)
Comprehensive loss	(26,471)	(18,473)
Net loss	(25,693)	(18,460)
Net loss	$ (25,693)	$ (18,460)
Net loss per share, basic (in dollars per share)	$ (0.98)	$ (2.91)
Net loss per share, diluted (in dollars per share)	$ (0.98)	$ (2.91)
Weighted-average shares used to compute basic net loss per share (in shares)	26,126,092	6,336,347
Weighted-average shares used to compute diluted net loss per share (in shares)	26,126,092	6,336,347

CONDENSED CONSOLIDATED STATEM_2

CONDENSED CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS’ EQUITY (unaudited) - USD ($) $ in Thousands	Total	Preferred Stock	Preferred StockSeries A Preferred Stock (as converted to shares of common stock)	Preferred StockSeries B Preferred Stock (as converted to shares of common stock)	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Loss	Accumulated Deficit
Beginning balance (in shares) at Dec. 31, 2020		0	398,487		4,231,135
Beginning balance at Dec. 31, 2020	$ 120,037	$ 0	$ 180,801		$ 42	$ 218,089	$ (8)	$ (278,887)
Stockholders’ deficit
Issuance of common stock upon the conversion of convertible preferred stock (in shares)			(43,664)		2,911,071
Issuance of common stock upon the conversion of convertible preferred stock	0		$ (19,811)		$ 29	19,782
Issuance of common stock upon exercise of warrants (in shares)					56,935
Issuance of common stock upon exercises of warrants	940				$ 1	939
Issuance of common stock for exercises of stock options and vesting of restricted stock units (in shares)					31,249
Issuance of common stock for exercises of stock options and vesting of restricted stock units	307					307
Issuance of common stock for cash under employee stock purchase plan (in shares)					980
Issuance of common stock for cash under employee stock purchase plan	12					12
Share-based compensation expense	3,175					3,175
Change in unrealized loss on investments	(13)						(13)
Net loss	(18,460)							(18,460)
Ending balance (in shares) at Mar. 31, 2021		0	354,823		7,231,370
Ending balance at Mar. 31, 2021	105,998	$ 0	$ 160,990		$ 72	242,304	(21)	(297,347)
Beginning balance (in shares) at Dec. 31, 2021			260,437	23,126	23,924,004
Beginning balance at Dec. 31, 2021	187,716		$ 118,164	$ 15,669	$ 239	412,101	(157)	(358,300)
Stockholders’ deficit
Issuance of common stock upon the conversion of convertible preferred stock (in shares)			(47,871)		3,191,555
Issuance of common stock upon the conversion of convertible preferred stock	0		$ (21,722)		$ 33	21,689
Issuance of common stock for exercises of stock options and vesting of restricted stock units (in shares)					47,735
Issuance of common stock for exercises of stock options and vesting of restricted stock units	667					667
Issuance of common stock for cash under employee stock purchase plan (in shares)					6,128
Issuance of common stock for cash under employee stock purchase plan	71					71
Share-based compensation expense	4,659					4,659
Change in unrealized loss on investments	(778)						(778)
Net loss	(25,693)							(25,693)
Ending balance (in shares) at Mar. 31, 2022			212,566	23,126	27,169,422
Ending balance at Mar. 31, 2022	$ 166,642		$ 96,442	$ 15,669	$ 272	$ 439,187	$ (935)	$ (383,993)

CONDENSED CONSOLIDATED STATEM_3

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Cash flows from operating activities:
Net loss	$ (25,693)	$ (18,460)
Adjustments to reconcile net loss to net cash used in operating activities:
Share-based compensation expense	4,659	3,175
Depreciation and amortization	40	33
Amortization of premiums and discounts on available-for-sale securities	274	232
Other	47	(5)
Changes in operating assets and liabilities:
Prepaid expenses and other assets	(740)	(3,622)
Unbilled revenue - related party	(71)	1,382
Deferred revenue - related party	(72)	(149)
Accounts payable	31	2,715
Accrued and other liabilities	483	3,160
Net cash used in operating activities	(21,042)	(11,539)
Cash flows from investing activities:
Purchases of short-term investments	(5,192)	(56,652)
Proceeds from maturities of short-term investments	14,234	67,539
Purchase of property and equipment, net	(179)	(15)
Net cash provided by investing activities	8,863	10,872
Cash flows from financing activities:
Proceeds from the issuance of common stock upon exercises of warrants	0	940
Proceeds from issuance of common stock upon the exercise of stock options	667	307
Proceeds from the issuance of common stock for cash under employee stock purchase plan	71	12
Net cash provided by financing activities	738	1,259
Net increase (decrease) in cash and cash equivalents	(11,441)	592
Cash and cash equivalents at beginning of period	42,299	45,897
Cash and cash equivalents at end of period	30,858	46,489
Supplemental disclosure of cash flow information
Purchase of property and equipment in accounts payable	$ 177	$ 0

DESCRIPTION OF BUSINESS

DESCRIPTION OF BUSINESS	3 Months Ended
	Mar. 31, 2022
Organization, Consolidation and Presentation of Financial Statements [Abstract]
DESCRIPTION OF BUSINESS	DESCRIPTION OF BUSINESS Viridian Therapeutics, Inc., a Delaware corporation (the “Company” or “Viridian”), is a biotechnology company advancing new treatments for patients suffering from serious diseases that are underserved by today’s therapies. The Company’s most advanced program, VRDN-001, is a differentiated monoclonal antibody targeting insulin-like growth factor-1 receptor (“IGF-1R”), a clinically and commercially validated target for the treatment of thyroid eye disease (“TED”). The Company’s second product candidate, VRDN-002, is a distinct anti-IGF-1R antibody that incorporates half-life extension technology, and is designed to be administered as a convenient, low-volume, subcutaneous injection. TED is a debilitating autoimmune disease that causes inflammation and fibrosis within the orbit of the eye which can cause double vision, pain, and potential blindness. Patients with severe disease often require multiple remedial surgeries to the orbit, eye muscles and eyelids. In addition to developing therapies for TED, the Company is executing a similar strategic approach to identify opportunities in other rare and/or serious disease indications. Liquidity The accompanying condensed consolidated financial statements have been prepared on a basis that assumes the Company is a going concern and do not include any adjustments to reflect the possible future effects on the recoverability and classification of assets or the amounts and classifications of liabilities that may result from any uncertainty related to its ability to continue as a going concern. The Company has funded its operations to date principally through proceeds received from the sale of the Company’s common stock, its Series A Preferred Stock, Series B Preferred Stock, and other equity securities, debt financings, license fees, and reimbursements received under collaboration agreements. Since its inception and through March 31, 2022, the Company has generated an accumulated deficit of $384.0 million. The Company expects to continue to generate operating losses for the foreseeable future. The Company has no products approved for commercial sale, has not generated any revenue from product sales, and cannot guarantee when or if it will generate any revenue from product sales. Substantially all of the Company’s operating losses resulted from expenses incurred in connection with its research and development programs and from general and administrative costs associated with its operations. The Company expects to incur significant expenses and operating losses for at least the next several years as it continues the development of, and seeks regulatory approval for, its product candidates. It is expected that operating losses will fluctuate significantly from quarter to quarter and year to year due to timing of development programs and efforts to achieve regulatory approval. As of March 31, 2022, the Company had approximately $175.4 million in cash, cash equivalents, and short-term investments. As of the issuance date of these condensed consolidated financial statements, the Company expects that its current resources will be sufficient to fund its operations for at least the next twelve months from the issuance of these financial statements. The Company will continue to require additional capital in order to continue to finance its operations. The amount and timing of future funding requirements will depend on many factors, including the pace and results of the Company’s clinical development efforts, equity financings, entering into license and collaboration agreements, and issuing debt or other financing vehicles. The Company’s ability to secure additional capital is dependent upon a number of factors, some of which are outside of the Company’s control, including success in developing its technology and drug product candidates, operational performance, and market conditions, including those resulting from the ongoing COVID-19 pandemic.

SUMMARY OF SIGNIFICANT ACCOUNTI

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	3 Months Ended
	Mar. 31, 2022
Accounting Policies [Abstract]
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Basis of Presentation The accompanying unaudited condensed consolidated financial statements have been prepared in conformity with U.S. generally accepted accounting principles (“U.S. GAAP”), for interim financial reporting and as required by Regulation S-X, Rule 10-01. Accordingly, they do not include all of the information and footnotes required by U.S. GAAP for complete financial statements. Any reference in these notes to applicable guidance is meant to refer to the authoritative U.S. GAAP as found in the Accounting Standards Codification (“ASC”), and Accounting Standards Update (“ASU”), or the Financial Accounting Standards Board (“FASB”). In the opinion of management, all adjustments, consisting of normal recurring accruals and revisions of estimates, considered necessary for a fair presentation of the unaudited condensed consolidated financial statements have been included. Interim results for the three months ended March 31, 2022, are not necessarily indicative of the results that may be expected for the fiscal year ending December 31, 2022, or any other future period. The accompanying unaudited condensed consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries. The Company’s subsidiaries have no employees or operations. All intercompany balances and transactions have been eliminated in consolidation. Management has determined that the Company operates in one segment, which is the business of developing and commercializing novel therapeutics. The information included in this Quarterly Report on Form 10-Q should be read in conjunction with the Company’s consolidated financial statements and the accompanying notes included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2021, filed with the U.S. Securities and Exchange Commission on March 11, 2022 (the “2021 Annual Report on Form 10-K”). The Company’s management performed an evaluation of its activities through the date of filing of these unaudited condensed consolidated financial statements and concluded that there are no subsequent events requiring disclosure, other than as disclosed. Risk and Uncertainties – Impact of the COVID-19 Pandemic The Company is subject to risks and uncertainties as a result of the ongoing COVID-19 pandemic. The virus continues to spread globally and the impact of this pandemic has been and may continue to be extensive in many aspects of society, which has resulted in and may continue to result in significant disruptions to the global economy, as well as businesses and capital markets around the world. The spread of COVID-19 has caused the Company to modify its business practices, including implementing an optional work-from-home policy for all employees who are able to perform their duties remotely and modified travel restrictions for employee travel pursuant to certain company guidelines, and it expects to continue to take actions as the Company determines are in the best interests of its employees, the patients it serves, and other business partners in light of COVID-19. Potential impacts to the Company’s business include temporary closures of its facilities or those of its vendors, disruptions or restrictions on its employees’ ability to travel, disruptions to or delays in ongoing laboratory experiments and operations, and the potential diversion of healthcare resources away from the conduct of clinical trials to focus on pandemic concerns, manufacturing delays or disruptions, and its ability to raise capital. As of March 31, 2022, there have been no material impacts to the Company as a result of the COVID-19 pandemic. The Company continually assesses the impacts of COVID-19 and the extent to which the pandemic may materially impact the Company’s financial condition, liquidity, or results of operations in the future is uncertain. Going Concern At each reporting period, the Company evaluates whether there are conditions or events that raise substantial doubt about the Company’s ability to continue as a going concern within one year after the date that the financial statements are issued. The Company is required to make certain additional disclosures if it concludes substantial doubt exists and it is not alleviated by the Company’s plans or when its plans alleviate substantial doubt about the Company’s ability to continue as a going concern. The Company’s evaluation entails, among other things, analyzing the results of the Company’s clinical development efforts, license and collaboration agreements as well as the entity’s current financial condition including conditional and unconditional obligations anticipated within a year, and related liquidity sources at the date the financial statements are issued. This is reflected in the Company’s prospective operating budgets and forecasts and compared to the current cash and cash equivalent balance. Use of Estimates The Company’s condensed consolidated financial statements are prepared in accordance with U.S. GAAP, which requires it to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and contingent liabilities at the date of the financial statements and the reported amounts of revenue and expenses during the reporting period. Significant estimates and assumptions reflected in these condensed consolidated financial statements include, but are not limited to, the accrual for clinical trial costs and other outsourced research and development expenses, and the valuation of share-based awards. Although these estimates are based on the Company’s knowledge of current events and actions it may take in the future, actual results may ultimately differ from these estimates and assumptions. Revenue Recognition The Company accounts for revenue in accordance with ASC Topic 606, Revenue from Contracts with Customers (“ASC 606”). The Company enters into collaboration agreements and certain other agreements that are within the scope of ASC 606, under which the Company licenses, may license, or grants an option to license rights to certain of the Company’s product candidates and performs research and development services in connection with such agreements. The terms of these agreements typically include payment of one or more of the following: non-refundable, up-front fees; reimbursement of research and development costs; developmental, clinical, regulatory, and commercial sales milestone payments; and royalties on net sales of licensed products. In accordance with ASC 606, the Company recognizes revenue when its customer obtains control of promised goods or services, in an amount that reflects the consideration which the Company expects to receive in exchange for those goods or services. To determine the appropriate amount of revenue to be recognized, for agreements within the scope of ASC 606, the Company performs the following five steps: (i) identification of the goods or services within the contract; (ii) determination of whether the promised goods or services are performance obligations, including whether they are distinct within the terms of the contract; (iii) measurement of the transaction price, including the constraint on variable consideration; (iv) allocation of the transaction price to the identified performance obligations; and (v) recognition of revenue when (or as) the Company satisfies each performance obligation. The Company only applies the five-step model to contracts when it is probable that the Company will collect consideration it is entitled to in exchange for the goods or services it transfers to the customer. The promised goods or services in the Company’s agreements typically consist of a license, or option to license, rights to the Company’s intellectual property or research and development services. Performance obligations are promises in a contract to transfer a distinct good or service to the customer and are considered distinct when (i) the customer can benefit from the good or service on its own or together with other readily available resources and (ii) the promised good or service is separately identifiable from other promises in the contract. In assessing whether promised goods or services are distinct, the Company considers factors such as the stage of development of the underlying intellectual property, the capabilities of the customer to develop the intellectual property on its own or whether the required expertise is readily available, and whether the goods or services are integral or dependent to other goods or services in the contract. The Company estimates the transaction price based on the amount expected to be received for transferring the promised goods or services in the contract. The consideration may include fixed consideration or variable consideration. At the inception of each agreement that includes variable consideration, the Company evaluates the amount of potential payment and the likelihood that the payments will be received. The Company utilizes either the most likely amount method or expected value method to estimate the amount expected to be received based on which method best predicts the amount expected to be received. The amount of variable consideration that is included in the transaction price may be constrained and is included in the transaction price only to the extent that it is probable that a significant reversal in the amount of the cumulative revenue recognized will not occur in a future period. The Company’s contracts often include development and regulatory milestone payments that are assessed under the most likely amount method and constrained if it is probable that a significant revenue reversal would occur. Milestone payments that are not within the Company’s control or the licensee’s control, such as regulatory approvals, are not considered probable of being achieved until those approvals are received. At the end of each reporting period, the Company re-evaluates the probability of achievement of such development and clinical milestones and any related constraint, and if necessary, adjusts its estimate of the overall transaction price. Any such adjustments are recorded on a cumulative catch-up basis, which would affect collaboration and other research and development revenue in the period of adjustment. For agreements that include sales-based royalties, including milestone payments based on the level of sales, and the license is deemed to be the predominant item to which the royalties relate, the Company recognizes revenue at the later of (i) when the related sales occur, or (ii) when the performance obligation to which some or all of the royalty has been allocated has been satisfied (or partially satisfied). To date, the Company has not recognized any royalty revenue resulting from any of the Company’s collaboration or strategic alliance agreements. The Company allocates the transaction price based on the estimated standalone selling price. The Company must develop assumptions that require judgment to determine the stand-alone selling price for each performance obligation identified in the contract. The Company utilizes key assumptions to determine the stand-alone selling price, which may include other comparable transactions, pricing considered in negotiating the transaction, and the estimated costs. Variable consideration is allocated specifically to one or more performance obligations in a contract when the terms of the variable consideration relate to the satisfaction of the performance obligation and the resulting amounts allocated are consistent with the amounts the Company would expect to receive for the satisfaction of each performance obligation. The consideration allocated to each performance obligation is recognized as revenue when control is transferred for the related goods or services. For performance obligations which consist of licenses and other promises, the Company utilizes judgment to assess the nature of the combined performance obligation to determine whether the combined performance obligation is satisfied over time or at a point in time and, if over time, the appropriate method of measuring progress. The Company evaluates the measure of progress each reporting period and, if necessary, adjusts the measure of performance and related revenue recognition. The Company receives payments from its customers based on billing schedules established in each contract. Up-front payments and fees are recorded as deferred revenue upon receipt or when due until the Company performs its obligations under these arrangements. Amounts are recorded as accounts receivable when the Company’s right to consideration is unconditional. Research and Development Research and development costs are expensed as incurred in performing research and development activities. The costs include employee-related expense including salaries, benefits, share-based compensation, restructuring charges, fees for acquiring and maintaining licenses under third-party license agreements, consulting fees, costs of research and development activities conducted by third parties on the Company’s behalf, costs to manufacture or have manufactured clinical trial materials, laboratory supplies, depreciation, and facilities and overhead costs. The Company records research and development expense in the period in which the Company receives or takes ownership of the applicable goods or when the applicable services are performed. In circumstances where amounts have been paid in excess of costs incurred, the Company records a prepaid expense. The Company records up-front and milestone payments to acquire and retain contractual rights to licensed technology as research and development expenses when incurred if there is uncertainty in the Company receiving future economic benefit from the acquired contractual rights. The Company considers future economic benefits from acquired contractual rights to licensed technology to be uncertain until such a drug candidate is approved for sale by the U.S. Food and Drug Administration or when other significant risk factors are abated. Clinical Trial and Preclinical Study Accruals The Company makes estimates of accrued expenses as of each balance sheet date in its condensed consolidated financial statements based on certain facts and circumstances at that time. The Company’s accrued expenses for clinical trials and preclinical studies are based on estimates of costs incurred for services provided by clinical research organizations, manufacturing organizations, and other providers. Payments under the Company’s agreements with external service providers depend on a number of factors, such as site initiation, patient screening, enrollment, delivery of reports, and other events. In accruing for these activities, the Company obtains information from various sources and estimates the level of effort or expense allocated to each period. Adjustments to the Company’s research and development expenses may be necessary in future periods as its estimates change. Share-Based Compensation The Company accounts for share-based compensation expense to employees and non-employees based on the fair value of each stock option or award on the date of the grant. The Company uses the Black-Scholes option pricing model to determine the fair value of stock options. The use of the Black-Scholes option-pricing model requires the Company to make assumptions with respect to the expected term of the option, the expected volatility of the common stock consistent with the expected life of the option, risk-free interest rates and expected dividend yields of the common stock. The Company recognizes share-based compensation expense for awards with service-based conditions using the straight-line method over the requisite service period, net of any actual forfeitures. Cash and Cash Equivalents All highly-liquid investments that have maturities of 90 days or less at the date of purchase are classified as cash equivalents. Cash equivalents are reported at cost, which approximates fair value due to the short maturities of these instruments. Investments The Company has designated its investments as available-for-sale securities and accounts for them at their respective fair values. The securities are classified as short-term or long-term based on the nature of the securities and their availability to meet current operating requirements. Securities that are readily available for use in current operations are classified as short-term available-for-sale securities and are reported as a component of current assets in the accompanying condensed consolidated balance sheets. Securities that are classified as available-for-sale are measured at fair value, including accrued interest, with temporary unrealized gains and losses reported as a component of stockholders’ equity until their disposition. The Company reviews available-for-sale securities at the end of each period to determine whether they remain available-for-sale based on its then-current intent. The cost of securities sold is based on the specific identification method. The securities are subject to a periodic impairment review. An impairment charge would occur when a decline in the fair value of the investments below the cost basis is judged to be other-than-temporary. Fair Value Measurements Certain assets and liabilities are carried at fair value under GAAP. Fair value is defined as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. Valuation techniques used to measure fair value must maximize the use of observable inputs and minimize the use of observable in puts. Financial assets and liabilities carried at fair value are to be classified and disclosed in one of the following three levels of the fair value hierarchy, of which the first two are considered observable and the last is considered unobservable: • Level 1 inputs utilize quoted prices (unadjusted) in active markets for identical assets or liabilities. • Level 2 inputs utilizes observable inputs other than Level 1 prices, such as quoted prices, for similar assets or liabilities, quoted market prices in markets that are not active, or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the related assets or liabilities. • Level 3 inputs are unobservable data points for the asset or liability and include situations where there is little, if any, market activity for the asset or liability. Certain of the Company’s financial instruments are not measured at fair value on a recurring basis but are recorded at amounts that approximate their fair value due to the short-term nature of their maturities, such as cash and cash equivalents, accounts receivable, accounts payable, and accrued expenses. The Company accounts for warrants to purchase its common stock pursuant to ASC Topic 470, Debt , and ASC Topic 480, Distinguishing Liabilities from Equity , and classifies warrants for common stock as liabilities or equity. The warrants classified as liabilities are reported at their estimated fair value (see Note 3. Fair Value Measurements ) and any changes in fair value are reflected in interest and other expense. The warrants classified as equity are reported at their estimated fair value with no subsequent remeasurement. The Company’s outstanding warrants are discussed in more detail in Note 8. Warrants . Fair Value of Financial Instruments Certain of the Company’s financial instruments are not measured at fair value on a recurring basis but are recorded at amounts that approximate their fair value due to the short-term nature of their maturities, such as cash and cash equivalents, accounts receivable, accounts payable, and accrued expenses. The Company accounts for warrants to purchase its stock pursuant to ASC Topic 470, Debt , and ASC Topic 480, Distinguishing Liabilities from Equity , and classifies warrants for common stock as liabilities or equity. The warrants classified as liabilities are reported at their estimated fair value and any changes in fair value are reflected in interest and other expense. The warrants classified as equity are reported at their estimated fair value with no subsequent remeasurement. The Company’s outstanding warrants are discussed in more detail in Note 8. Warrants . Concentrations of Credit Risk Financial instruments that potentially subject the Company to concentrations of credit risk consist primarily of cash equivalents, which include short-term investments that have maturities of less than three months. 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. The Company invests its excess cash primarily in deposits and money market funds held with one financial institution. Property and Equipment The Company carries its property and equipment at cost, less accumulated depreciation and amortization. Depreciation is computed using the straight-line method over the estimated useful lives of the assets, generally three Operating Lease Right-of-Use Asset The Company determines if an arrangement is, or contains, a lease at contract inception and during modifications or renewal of existing leases. Operating lease assets represent the Company’s right to use an underlying asset for the lease term and operating lease liabilities represent the Company’s obligation to make lease payments arising from the lease. The Company has recorded operating lease assets and liabilities pursuant to the guidance in Accounting Standards Update (“ASU”) No. 2016-02 , Leases (Topic 842), and subsequent amendments to the initial guidance: ASU No. 2017-13, ASU No. 2018-10, and ASU No. 2018-11 (collectively, “ASC 842”). These operating lease assets and liabilities are recognized at the commencement date of the lease based upon the present value of lease payments over the lease term. The lease payments used to determine the Company’s operating lease assets may include lease incentives, stated rent increases, and escalation clauses and are recognized in the Company’s operating lease assets in the Company’s condensed consolidated balance sheets. The Company’s operating leases are reflected in operating lease right-of-use asset and operating lease liability within accrued and other liabilities in the Company’s condensed consolidated balance sheets. Lease expense for minimum lease payments is recognized on a straight-line basis over the lease term. Short-term leases, defined as leases that have a lease term of 12 months or less at the commencement date, are excluded from this treatment and are recognized on a straight-line basis over the term of the lease. Refer to Note 6. Commitments and Contingencies - Lease Obligations for additional information related to the Company’s operating leases. Convertible Preferred Stock The Company records shares of non-voting convertible preferred stock at their respective fair values on the dates of issuance, net of issuance costs. The Company has applied the guidance in ASC 480-10-S99-3A, SEC Staff Announcement: Classification and Measurement of Redeemable Securities , and at issuance classified the Series A Preferred Stock outside of stockholders’ equity because, if convertibility of Series A Preferred Stock into common stock was not approved by the stockholders, the Series A Preferred Stock would be redeemable at the option of the holders for cash equal to the closing price of the common stock on last trading day prior to the holder’s redemption request. On December 31, 2020, the stockholders approved the convertibility of the Series A Preferred Stock into common stock and as such, the Company reclassified the Series A Preferred Stock to permanent equity. In September 2021, the Company issued Series B Preferred Stock with conversion rights which the Company has classified as permanent equity. Impairment of Long-Lived Assets The Company assesses the carrying amount of its property and equipment whenever events or changes in circumstances indicate the carrying amount of such assets may not be recoverable. No impairment charges were recorded during the three months ended March 31, 2022 and 2021. Net Loss per Share Basic net loss per share is calculated by dividing the net loss by the weighted-average number of shares of common stock outstanding during the period without consideration of common stock equivalents. Since the Company was in a loss position for all periods presented, diluted net loss per share is the same as basic net loss per share for all periods, as the inclusion of all potential common shares outstanding is antidilutive. Comprehensive Loss Comprehensive loss is comprised of net loss and adjustments for the change in unrealized gains and losses on investments. Unrealized accumulated comprehensive gains or losses are reflected as a separate component in the condensed consolidated statements of changes in stockholders’ equity. Income Taxes The Company accounts for income taxes by using an asset and liability method of accounting for deferred income taxes. Deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases. A valuation allowance is recorded to the extent it is more likely than not that a deferred tax asset will not be realized. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in operations in the period that includes the enactment date. The Company’s significant deferred tax assets are for net operating loss carryforwards, tax credits, accruals and reserves, and capitalized start-up costs. The Company has provided a valuation allowance for its entire net deferred tax assets since inception as, due to its history of operating losses, the Company has concluded that it is more likely than not that its deferred tax assets will not be realized. The Company has no unrecognized tax benefits. The Company classifies interest and penalties arising from the underpayment of income taxes in the condensed consolidated statements of operations and comprehensive loss as general and administrative expenses. No such expenses have been recognized during the three months ended March 31, 2022 and 2021. Warrants Upon the issuance of warrants to purchase shares of common stock, the Company evaluates the terms of the warrant issue to determine the appropriate accounting and classification of the warrant issue pursuant to FASB ASC Topic 480, Distinguishing Liabilities from Equity , FASB ASC Topic 505, Equity , FASB ASC 815, Derivatives and Hedging, and ASC 718, Compensation - Stock Compensation . Warrants are classified as liabilities when the Company may be required to settle a warrant exercise in cash and classified as equity when the Company settles a warrant exercise in shares of its common stock. Liability-classified warrants are valued at fair value at the date of issue and at each reporting date pursuant to FASB ASC 820, Fair Value Measurement , and are reflected as a warrant liability on the Company’s condensed consolidated balance sheets. Any changes in the warrant liability during each reporting period would be reflected as other expense in the condensed consolidated statement of operations and comprehensive loss. Segment Information The Company operates in one operating segment and, accordingly, no segment disclosures have been presented herein. All equipment, leasehold improvements, and other fixed assets are physically located within the United States and all agreements with the Company’s partners are denominated in U.S. dollars, except where noted. Recent Accounting Pronouncements – To Be Adopted From time to time, new accounting pronouncements are issued by the FASB or other standard setting bodies that the Company adopts as of the specified effective date. The Company does not believe that the adoption of recently issued standards have or may have a material impact on the Company’s consolidated financial statements or disclosures.

FAIR VALUE MEASUREMENTS

FAIR VALUE MEASUREMENTS	3 Months Ended
	Mar. 31, 2022
Fair Value Disclosures [Abstract]
FAIR VALUE MEASUREMENTS	FAIR VALUE MEASUREMENTS Investments The following table provides details regarding the Company’s short-term investments: (in thousands) Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value March 31, 2022 Money market funds $ 30,758 $ — $ — $ 30,758 U.S. treasury securities 27,358 1 (252) 27,107 U.S. corporate paper and bonds 113,562 — (639) 112,923 International corporate bond holdings 4,585 — (45) 4,540 Total $ 176,263 $ 1 $ (936) $ 175,328 December 31, 2021 Money market funds $ 42,199 $ — $ — $ 42,199 U.S. treasury securities 22,215 — (54) 22,161 U.S. corporate paper and bonds 128,005 6 (94) 127,917 International corporate bond holdings 4,603 — (15) 4,588 Total $ 197,022 $ 6 $ (163) $ 196,865 The money market funds above are included in cash and cash equivalents on the Company’s condensed consolidated balance sheets. As of March 31, 2022, the Company considers the unrealized losses in its investment portfolio to be temporary in nature and not due to credit losses. The Company has the intent and ability to hold such investments until their recovery at fair value. The Company had zero and $4 thousand in realized gains in its available for sale securities during the three months ended March 31, 2022 and 2021, respectively. The contractual maturity dates of all of the Company’s investments are all less than 24 months. Fair Value Measurements The following tables summarize the Company’s assets and liabilities that are measured at fair value on a recurring basis: (in thousands) Quoted Prices in Active Markets Significant Other Observable Inputs Significant Unobservable Inputs Total March 31, 2022 Assets: Cash equivalents: Money market funds $ 30,758 $ — $ — $ 30,758 Short-term investments: U.S. treasury securities — 27,109 — 27,109 U.S. corporate paper and bonds — 112,923 — 112,923 International corporate bond holdings — 4,538 — 4,538 Total cash equivalents and short-term investments $ 30,758 $ 144,570 $ — $ 175,328 December 31, 2021 Assets: Cash equivalents: Money market funds $ 42,199 $ — $ — $ 42,199 Short-term investments: U.S. treasury securities — 22,161 — 22,161 U.S. corporate paper and bonds — 127,917 — 127,917 International corporate bond holdings — 4,588 — 4,588 Total cash equivalents and short-term investments $ 42,199 $ 154,666 $ — $ 196,865

ACCRUED LIABILITIES

ACCRUED LIABILITIES	3 Months Ended
	Mar. 31, 2022
Payables and Accruals [Abstract]
ACCRUED LIABILITIES	ACCRUED LIABILITIES Accrued liabilities consisted of the following: March 31, December 31, (in thousands) Accrued outsourced clinical trials and preclinical studies $ 8,647 $ 6,316 Accrued employee compensation and related taxes 1,548 3,652 Operating lease liability, short-term 579 520 Accrued legal fees and expenses 272 80 Accrued other professional service fees 131 140 Value of liability-classified stock purchase warrants 100 100 Other accrued liabilities 283 210 $ 11,560 $ 11,018

COLLABORATION AGREEMENTS

COLLABORATION AGREEMENTS	3 Months Ended
	Mar. 31, 2022
Organization, Consolidation and Presentation of Financial Statements [Abstract]
COLLABORATION AGREEMENTS	COLLABORATION AGREEMENTS License Agreement with Zenas BioPharma In October 2020, the Company became party to a license agreement with Zenas BioPharma (Cayman) Limited (“Zenas BioPharma”) to license technology comprising certain materials, patent rights, and know-how to Zenas BioPharma. Since February 2021, the Company has entered into several letter agreements with Zenas BioPharma pursuant to which the Company agreed to provide assistance to Zenas BioPharma with certain development activities, including manufacturing. The license agreement and subsequent letter agreements (collectively, the “Zenas Agreements”) were negotiated with a single commercial objective and are treated as a combined contract for accounting purposes. Under the terms of the Zenas Agreements, the Company granted Zenas BioPharma an exclusive license to develop, manufacture, and commercialize certain IGF-1R directed antibody products for non-oncology indications in the greater area of China. As consideration for the Zenas Agreements, the transaction price included upfront non-cash consideration and variable consideration in the form of payment for the Company’s goods and services and milestone payments due upon the achievement of specified events. Under the Zenas Agreements, the Company can receive non-refundable milestone payments upon achieving specific milestone events during the contract term. Additionally, the Company may receive royalty payments based on a percentage of the annual net sales of any licensed products sold on a country-by-country basis in the greater area of China. The royalty percentage may vary based on different tiers of annual net sales of the licensed products made. Zenas BioPharma is obligated to make royalty payments to the Company for the royalty term in the Zenas Agreements. The Zenas Agreements would qualify as a collaborative arrangement under the scope of Accounting Standards Codification, Topic 808, Collaborative Arrangements (“ASC 808”). While this arrangement is in the scope of ASC 808, the Company applied ASC 606 to account for certain aspects of this arrangement. The Company applied ASC 606 for certain activities within the arrangement associated with the Company’s transfer of a good or service (i.e., a unit of account) that is part of the Company’s ongoing major or central operations. The Company allocated the transaction price based on the relative estimated standalone selling prices of each performance obligation or, in the case of certain variable consideration, to one or more performance obligations. Research and development activities are priced generally at cost. The Company’s license of goods and services to Zenas BioPharma during the contract term was determined to be a single performance obligation satisfied over time. The Company will recognize the transaction price from the license agreement over the Company’s estimated period to complete its activities. At the inception of the arrangement, the Company evaluated whether the milestones were considered probable of being reached and estimated the amount to be included in the transaction price using the most likely amount method. As it was not probable that a significant revenue reversal would not occur, none of the associated milestone payments were included in the transaction price at contract inception. For the sales-based royalties included in the arrangement, the license was deemed to be the predominant item to which the royalties relate. The Company will recognize royalty revenues at the later of (i) when the related sales occur, or (ii) when the performance obligation to which some or all of the royalty has been allocated has been satisfied (or partially satisfied). During the three months ended March 31, 2022 and 2021, the Company recognized $0.2 million and $1.5 million, respectively, of collaboration revenue related to the Zenas Agreements. As of March 31, 2022, the Zenas Agreements are considered related party transactions because Fairmount Funds Management LLC beneficially owns more than 5% of the Company’s common stock and is also a 5% or greater stockholder of Zenas BioPharma and has a seat on Zenas BioPharma’s board of directors. Antibody and Discovery Option Agreement with Paragon Therapeutics, Inc. In January 2022, the Company and Paragon Therapeutics, Inc. (“Paragon”) entered into an antibody and discovery option agreement (the “Paragon Agreement”) under which the Company and Paragon will cooperate to develop one or more antibodies. Under the terms of the Paragon Agreement, Paragon will perform certain development activities in accordance with an agreed upon research plan, and the Company will pay Paragon agreed upon development fees in exchange for Paragon’s commitment of the necessary personnel and resources to perform these activities. The Paragon Agreement stipulates a final deliverable to the Company comprising of a report summarizing the experiments and processes performed under the research plan (the “Final Deliverable”). Additionally, Paragon agreed to grant the Company an option for an exclusive license to all of Paragon’s right, title and interest in and to certain antibody technology and the Final Deliverable, and a non-exclusive license to certain background intellectual property owned by Paragon solely to research, develop, make, use, sell, offer for sale and import of the licensed intellectual property and resulting products worldwide (each, an “Option” and together, the “Options”). Paragon also granted to the Company a limited, exclusive, royalty-free license, without the right to sublicense, to certain antibody technology and the Final Deliverable, and a non-exclusive, royalty-free license without the right to sublicense, under certain background intellectual property owned by Paragon, solely to evaluate the antibody technology and Option and for the purpose of allowing the Company to determine whether to exercise the Option with respect to certain programs. The Company may, at its sole discretion, exercise the Option with respect to specified programs at any time until the date that is 90 days after the Company’s receipt of the Final Deliverable the applicable program, or such longer period as agreed upon by the parties (“Option Period”) by delivering written notice of such exercise to Paragon. If the Company fails to exercise an Option prior to expiration of the applicable Option Period, such Option for such Program will terminate. In consideration for Paragon's grant of the Options to the Company, the Company paid to Paragon a non-refundable, non-creditable one-time fee of $2.5 million, which was recorded as research and development expense during the three months ended March 31, 2022. The non-refundable upfront fee is separate from any development costs or cost advance paid or owing with respect to the specified program.

COMMITMENTS AND CONTINGENCIES

COMMITMENTS AND CONTINGENCIES	3 Months Ended
	Mar. 31, 2022
Commitments and Contingencies Disclosure [Abstract]
COMMITMENTS AND CONTINGENCIES	COMMITMENTS AND CONTINGENCIES License Agreement with ImmunoGen, Inc. In October 2020, the Company became party to a license agreement (the “ImmunoGen License Agreement”) with Immunogen, Inc. (“ImmunoGen”), under which the Company obtained an exclusive, sublicensable, worldwide license to certain patents and other intellectual property rights to develop, manufacture, and commercialize certain products for non-oncology and non-radiopharmaceutical indications. In consideration for rights granted by ImmunoGen, the Company is obligated to make certain future development milestone payments of up to $48.0 million upon the achievement of specified clinical and regulatory milestones. In December 2021, the Company paid a $2.5 million milestone payment to ImmunoGen upon the submission of an Investigational New Drug (“IND”) application for VRDN-001 with the U.S. Food and Drug Administration. Additionally, if the Company successfully commercializes any product candidate subject to the ImmunoGen License Agreement, it is responsible for royalty payments equal to a percentage in the mid-single digits of net sales and commercial milestone payments of up to $95.0 million. The Company is obligated to make any such royalty payments on a product-by-product and country-by-country basis from the first commercial sale of a specified product in each country until the later of (i) the expiration of the last patent claim subject to the ImmunoGen License Agreement in such country, (ii) the expiration of any applicable regulatory exclusivity obtained for each product in such country, or (iii) the 12th anniversary of the date of the first commercial sale of such product in such country. License Agreements with Xencor, Inc. In December 2021, the Company entered into a subsequent technology license agreement with Xencor (the “2021 Xencor License Agreement”) for a non-exclusive license to certain antibody libraries developed by Xencor. Under the 2021 Xencor License Agreement, the Company received a one-year research license to review the antibodies and the right to select up to three antibodies for further development. In consideration for rights granted by Xencor, the Company issued 394,737 shares of its common stock to Xencor in December 2021. The shares were valued at $7.5 million and recorded as research and development expense during the year ended December 31, 2021. Under the terms of the 2021 Xencor License Agreement, if successful, for each licensed product, the Company would be obligated to make future milestone payments of up to $27.8 million, which includes development milestone payments of up to $4.8 million, special milestone payments of up to $3.0 million, and commercial milestone payments of up to $20.0 million. Additionally, for each licensed product that the Company successfully commercializes, it would be responsible for royalty payments equal to a percentage in the mid-single digits of net sales. In December 2020, the Company entered into a license agreement (the “Xencor License Agreement”) with Xencor, Inc. (“Xencor”), under which Xencor granted the Company rights to an exclusive, worldwide, sublicensable, non-transferable, royalty-bearing license to use specified Xencor technology for the research, development, manufacturing, and commercialization of therapeutic antibodies targeting IGF-1R indications. In consideration for rights granted by Xencor, the Company issued 322,407 shares of its common stock in December 2020. The shares were valued at $6.0 million and recorded as research and development expense in 2020. Under the terms of the Xencor License Agreement, the Company is obligated to make future development milestone payments of up to $30.0 million. Additionally, if the Company successfully commercializes any product candidate subject to the Xencor License Agreement, it is responsible for royalty payments equal to a percentage in the mid-single digits of net sales and commercial milestone payments of up to $25.0 million. The Company is obligated to make any such royalty payments on a product-by-product and country-by-country basis from the first commercial sale of products containing the licensed technology in each country until the later of (i) the expiration of the last patent claim subject to the Xencor License Agreement in such country, (ii) the expiration of any applicable regulatory exclusivity obtained, or (iii) the 12 th anniversary of the date of the first commercial sale. Lease Obligations The Company is party to a multi-year, non-cancelable lease agreement for its Colorado-based office and lab space. The lease agreement includes rent escalation clauses through the lease term and a Company option to extend the lease term for up to three terms of three years each. Minimum base lease payments under the lease agreement, including the impact of tenant improvement allowances, are recognized on a straight-line basis over the full term of the lease. The lease term was amended in March 2021 to extend the lease maturity date to December 31, 2024. Upon adoption of ASC 842 and upon subsequent modification of the lease in 2020 and in March 2021, the Company recognized a right-of-use asset and corresponding lease liability for the lease agreement of approximately $1.6 million by calculating the present value of lease payments, discounted at 6%, the Company’s estimated incremental borrowing rate, over the 12 months expected remaining term. In April 2021, the Company entered into a sublease with Cogent Biosciences, Inc. (“Cogent”) for its Colorado-based office and lab space, which was subsequently amended in November 2021 to extend the term of the sublease. As of the sublease inception date, Fairmount Funds Management LLC beneficially owned more than 5% of the Company’s common stock and Cogent’s capital stock. Under the terms of the sublease, which expires in June 2022, Cogent will pay the Company an aggregate of $0.2 million in rent payments plus related taxes and lease operating costs. The sublease was negotiated based on market rates and is on terms that the Company believes are no less favorable than would have been reached with an unrelated third party. In October 2020, the Company became party to a multi-year, non-cancelable lease agreement for its Massachusetts-based office space (the “Original Lease”). The Original Lease included rent escalation clauses through the lease term. Minimum base lease payments under the lease agreement are recognized on a straight-line basis over the full term of the lease. Upon assumption of the Original Lease, the Company recognized a right-of-use asset and corresponding lease liability for the Original Lease of $0.1 million by calculating the present value of lease payments, discounted at 6%, the Company’s estimated incremental borrowing rate, over the expected remaining term. In July 2021, the Company amended the Original Lease to increase its Massachusetts-based office space (the “Amended Lease”). The office space leased under the Original Lease will expire in February 2023 and the additional office space leased under the Amended Lease will expire in October 2024. Consolidated future minimum lease payments as of March 31, 2022, were approximately $1.8 million through 2025. As of March 31, 2022, the Company’s operating lease obligations were reflected as short-term operating lease liabilities of $0.6 million within accrued liabilities other liabilities Amortization of the operating lease right-of-use assets, and corresponding reduction of operating lease obligations, amounted to $0.1 million for the three months ended March 31, 2022 and 2021, which was included in operating expense in the condensed consolidated statements of operations and comprehensive loss. The Company is also required to pay for operating expenses related to the leased space, which were $51 thousand and $54 thousand for the three months ended March 31, 2022 and 2021, respectively. The operating expenses are incurred separately and were not included in the present value of lease payments.

CAPITAL STOCK

CAPITAL STOCK	3 Months Ended
	Mar. 31, 2022
Equity [Abstract]
CAPITAL STOCK	CAPITAL STOCK Common Stock Under the Company’s second restated certificate of incorporation, the Company is authorized to issue 205,000,000 shares of its stock, of which 200,000,000 shares have been designated as common stock and 5,000,000 shares have been designated as Preferred Stock, both with a par value of $0.01 per share. The number of authorized shares of common stock may be increased or decreased by the affirmative vote of the holders of a majority of the Company’s stock who are entitled to vote. Each share of common stock is entitled to one vote. The holders of common stock are entitled to receive dividends when and as declared or paid by its board of directors. Common Stock Sales Agreements Jefferies LLC In November 2021, the Company entered into an Open Market Sale Agreement SM (the “November 2021 ATM Agreement”) with Jefferies, relating to shares of its common stock. In accordance with the terms of the November 2021 ATM Agreement, the Company may offer and sell shares of its common stock having an aggregate offering price of up to $75.0 million from time to time at prices and on terms to be determined by market conditions at the time of offering, with Jefferies acting as its sales agent. Jefferies will receive a commission of 3.0% of the gross proceeds of any shares of common stock sold under the November 2021 ATM Agreement. As of March 31, 2022, no shares have been sold under the November 2021 ATM Agreement with Jefferies. In April 2021, the Company entered into an Open Market Sale Agreement SM (the “April 2021 ATM Agreement”) with Jefferies LLC (“Jefferies”) under which the Company could offer and sell, from time to time at its sole discretion, shares of its common stock having an aggregate offering price of up to $50.0 million through Jefferies as its sales agent in an “at the market” offering. Jefferies will receive a commission equal to 3.0% of the gross sales proceeds of any common stock sold through Jefferies under the April 2021 ATM Agreement. The April 2021 ATM Agreement was replaced by the November 2021 ATM Agreement. Through December 31, 2021 (prior to its termination), the Company sold an aggregate of 2,551,269 shares of common stock pursuant to the terms of the April 2021 ATM Agreement, at a volume weighted-average price of $13.13 per share, for aggregate net proceeds of approximately $32.4 million, including commissions to Jefferies as sales agent. Common Stock Purchase Agreement - Aspire Capital Fund, LLC In December 2019, the Company entered into a common stock purchase agreement (“the Aspire Stock Purchase Agreement”), with Aspire Capital Fund, LLC (“Aspire Capital”), which provides that, subject to the terms, conditions, and limitations set forth therein, Aspire Capital is committed to purchase up to an aggregate of $20.0 million of shares of common stock over the 30-month term of the Aspire Stock Purchase Agreement. Through December 31, 2020, the Company has sold to Aspire Capital 412,187 shares of common stock at a weighted-average price of $21.35 per share for aggregate net proceeds of $8.8 million. The Company did not sell any shares to Aspire Capital during the year ended December 31, 2021. As of March 31, 2022, the Company has the ability to sell an additional $10.2 million of shares of common stock to Aspire Capital. Under the Aspire Stock Purchase Agreement, the Company has the right, in its sole discretion, on any trading day selected by it, and within certain specified limitations, to present Aspire Capital with a purchase notice, directing Aspire Capital (as principal) to purchase up to 13,333 shares of common stock per business day at a per share price equal to the lesser of (i) the lowest sale price of common stock on the purchase date or (ii) the average of the three lowest closing sale prices for the common stock during the 10 consecutive business days ending on the business day immediately preceding the purchase date. The Company also has the right to require Aspire Capital to purchase up to an additional 30% of the trading volume of the shares for the next business day at a purchase price (the “VWAP Purchase Price”), equal to the lesser of: (i) the closing sale price of the shares on the purchase date, or (ii) ninety-seven percent (97%) of the next business day’s volume weighted average-price (each such purchase, a “VWAP Purchase”). The Company shall have the right, in its sole discretion, to determine a maximum number of shares and set a minimum market price threshold for each VWAP Purchase. The Company can only require a VWAP Purchase if the Company has also submitted a regular purchase on the notice date for the VWAP Purchase. There are no limits on the number of VWAP purchases that the Company may require. The Aspire Stock Purchase Agreement may be terminated by the Company at any time, at the Company’s discretion, without any cost to the Company. There are no limitations on use of proceeds, financial or business covenants, restrictions on future financings, rights of first refusal, participation rights, penalties, or liquidated damages in the Aspire Stock Purchase Agreement. Common Stock Public Offering 2021 Public Offering In September 2021, the Company entered into an underwriting agreement (the “2021 Underwriting Agreement”) with Jeffries LLC, SVB Leerink LLC and Evercore Group, LLC (collectively, the “Underwriters”) for the sale and issuance of 7,344,543 shares of common stock, which includes 1,159,089 shares of common stock issued in connection with the exercise in full by the underwriters of their option to purchase additional shares, at a public offering price of $11.00 per share and 23,126 shares of Series B Non-Voting Convertible Preferred Stock at a public offering price of $733.37 per share (collectively the “2021 Public Offering”). The aggregate gross proceeds to the Company from the 2021 Public Offering are approximately $97.7 million, before deducting underwriting discounts and commissions and estimated offering expenses payable by the Company. Preferred Stock Under the Company’s second restated certificate of incorporation, the Company’s board of directors has the authority to designate and issue up to 5,000,000 shares of preferred stock, at its discretion, in one or more classes or series and to fix the powers, preferences and rights, and the qualifications, limitations, or restrictions thereof, including dividend rights, conversion rights, voting rights, terms of redemption, and liquidation preferences, without further vote or action by the Company’s stockholders. Series A Preferred Stock Holders of Series A Preferred Stock are entitled to receive dividends on shares of Series A Preferred Stock equal, on an as-if-converted-to-Common-Stock basis, and in the same form as dividends actually paid on shares of the common stock. Except as otherwise required by law, the Series A Preferred Stock does not have voting rights. However, as long as any shares of Series A Preferred Stock are outstanding, the Company will not, without the affirmative vote of the holders of a majority of the then outstanding shares of the Series A Preferred Stock, (i) alter or change adversely the powers, preferences or rights given to the Series A Preferred Stock, (ii) alter or amend the Certificate of Designation, (iii) amend its certificate of incorporation or other charter documents in any manner that adversely affects any rights of the holders of Series A Preferred Stock, (iv) increase the number of authorized shares of Series A Preferred Stock, (v) at any time while at least 30% of the originally issued Series A Preferred Stock remains issued and outstanding, consummate a Fundamental Transaction (as defined in the Certificate of Designation) or (vi) enter into any agreement with respect to any of the foregoing. The Series A Preferred Stock does not have a preference upon any liquidation, dissolution, or winding-up of the Company. Each share of Series A Preferred Stock is convertible into 66.67 shares of common stock at any time at the option of the holder thereof, subject to certain limitations, including that a holder of Series A Preferred Stock is prohibited from converting shares of Series A Preferred Stock into shares of common stock if, as a result of such conversion, such holder, together with its affiliates, would beneficially own more than a specified percentage (to be established by the holder between 4.99% and 19.99%) of the total number of shares of common stock issued and outstanding immediately after giving effect to such conversion. As of December 31, 2021, there were 260,437 shares of Series A Preferred Stock outstanding. During the three months ended March 31, 2022, 47,871 shares of Series A Preferred Stock were converted into 3,191,555 shares of common stock. As of March 31, 2022 there were 212,566 shares of Series A Preferred Stock outstanding. Series B Preferred Stock Each share of Series B Preferred Stock is convertible into 66.67 shares of common stock, subject to certain limitations, including that a holder of Series B Preferred Stock is prohibited from converting shares of Series B Preferred Stock into shares of common stock if, as a result of such conversion, such holder, together with its affiliates, would beneficially own more than a specified percentage (to be established by the holder between 4.9% and 19.9%) of the total number of shares of common stock issued and outstanding immediately after giving effect to such conversion. The powers, preferences, rights, qualifications, limitations, and restrictions applicable to the Series B Preferred Stock are set forth in the Certificate of Designation filed in connection with the Offering. Holders of Series B Preferred Stock are entitled to receive dividends on shares of Series B Preferred Stock equal, on an as-if-converted-to-Common-Stock basis, and in the same form as dividends actually paid on shares of the common stock. Except as otherwise required by law, the Series B Preferred Stock does not have voting rights. However, as long as any shares of Series B Preferred Stock are outstanding, the Company will not, without the affirmative vote of the holders of a majority of the then outstanding shares of the Series B Preferred Stock, (i) alter or change adversely the powers, preferences or rights given to the Series B Preferred Stock, (ii) alter or amend the Certificate of Designation, or (iii) amend its certificate of incorporation or other charter documents in any manner that adversely affects any rights of the holders of Series B Preferred Stock. The Series B Preferred Stock does not have a preference upon any liquidation, dissolution, or winding-up of the Company. As of December 31, 2021, there were 23,126 shares of Series B Preferred Stock outstanding. No shares of Series B Preferred Stock were converted into common stock during the three months ended March 31, 2022. The following table presents information about the Company’s outstanding warrants: Number of Underlying Shares (1) Weighted-Average Exercise Price at March 31, 2022 Remaining Contractual Life at March 31, 2022 March 31, December 31, Liability-classified warrants Issued April 2017 781 781 $127.95 3.08 Equity-classified warrants Acquired October 2020 29,446 29,446 $0.01 8.49 Issued February 2020 (2) 388,796 388,796 $15.28 2.87 Issued November 2017 1,606 1,606 $0.41 2.63 Subtotal 419,848 419,848 $15.70 Total warrants 420,629 420,629 $15.91 ____________________ (1) If the Company subdivides (by any stock split, stock dividend, recapitalization, or otherwise) its outstanding shares of its common stock into a smaller number of shares, the warrant exercise price is proportionately reduced and the number of shares under outstanding warrants is proportionately increased. Additionally, if the Company combines (by combination, reverse stock split, or otherwise) its outstanding shares of common stock into a smaller number of shares, the warrant exercise price is proportionately increased and the number of shares under outstanding warrants is proportionately decreased. (2) Subject to specified conditions, the Company may voluntarily reduce the warrant exercise price of the warrants issued in February 2020. There were no warrants exercised during the three months ended March 31, 2022.

WARRANTS

WARRANTS	3 Months Ended
	Mar. 31, 2022
Other Liabilities Disclosure [Abstract]
WARRANTS	CAPITAL STOCK Common Stock Under the Company’s second restated certificate of incorporation, the Company is authorized to issue 205,000,000 shares of its stock, of which 200,000,000 shares have been designated as common stock and 5,000,000 shares have been designated as Preferred Stock, both with a par value of $0.01 per share. The number of authorized shares of common stock may be increased or decreased by the affirmative vote of the holders of a majority of the Company’s stock who are entitled to vote. Each share of common stock is entitled to one vote. The holders of common stock are entitled to receive dividends when and as declared or paid by its board of directors. Common Stock Sales Agreements Jefferies LLC In November 2021, the Company entered into an Open Market Sale Agreement SM (the “November 2021 ATM Agreement”) with Jefferies, relating to shares of its common stock. In accordance with the terms of the November 2021 ATM Agreement, the Company may offer and sell shares of its common stock having an aggregate offering price of up to $75.0 million from time to time at prices and on terms to be determined by market conditions at the time of offering, with Jefferies acting as its sales agent. Jefferies will receive a commission of 3.0% of the gross proceeds of any shares of common stock sold under the November 2021 ATM Agreement. As of March 31, 2022, no shares have been sold under the November 2021 ATM Agreement with Jefferies. In April 2021, the Company entered into an Open Market Sale Agreement SM (the “April 2021 ATM Agreement”) with Jefferies LLC (“Jefferies”) under which the Company could offer and sell, from time to time at its sole discretion, shares of its common stock having an aggregate offering price of up to $50.0 million through Jefferies as its sales agent in an “at the market” offering. Jefferies will receive a commission equal to 3.0% of the gross sales proceeds of any common stock sold through Jefferies under the April 2021 ATM Agreement. The April 2021 ATM Agreement was replaced by the November 2021 ATM Agreement. Through December 31, 2021 (prior to its termination), the Company sold an aggregate of 2,551,269 shares of common stock pursuant to the terms of the April 2021 ATM Agreement, at a volume weighted-average price of $13.13 per share, for aggregate net proceeds of approximately $32.4 million, including commissions to Jefferies as sales agent. Common Stock Purchase Agreement - Aspire Capital Fund, LLC In December 2019, the Company entered into a common stock purchase agreement (“the Aspire Stock Purchase Agreement”), with Aspire Capital Fund, LLC (“Aspire Capital”), which provides that, subject to the terms, conditions, and limitations set forth therein, Aspire Capital is committed to purchase up to an aggregate of $20.0 million of shares of common stock over the 30-month term of the Aspire Stock Purchase Agreement. Through December 31, 2020, the Company has sold to Aspire Capital 412,187 shares of common stock at a weighted-average price of $21.35 per share for aggregate net proceeds of $8.8 million. The Company did not sell any shares to Aspire Capital during the year ended December 31, 2021. As of March 31, 2022, the Company has the ability to sell an additional $10.2 million of shares of common stock to Aspire Capital. Under the Aspire Stock Purchase Agreement, the Company has the right, in its sole discretion, on any trading day selected by it, and within certain specified limitations, to present Aspire Capital with a purchase notice, directing Aspire Capital (as principal) to purchase up to 13,333 shares of common stock per business day at a per share price equal to the lesser of (i) the lowest sale price of common stock on the purchase date or (ii) the average of the three lowest closing sale prices for the common stock during the 10 consecutive business days ending on the business day immediately preceding the purchase date. The Company also has the right to require Aspire Capital to purchase up to an additional 30% of the trading volume of the shares for the next business day at a purchase price (the “VWAP Purchase Price”), equal to the lesser of: (i) the closing sale price of the shares on the purchase date, or (ii) ninety-seven percent (97%) of the next business day’s volume weighted average-price (each such purchase, a “VWAP Purchase”). The Company shall have the right, in its sole discretion, to determine a maximum number of shares and set a minimum market price threshold for each VWAP Purchase. The Company can only require a VWAP Purchase if the Company has also submitted a regular purchase on the notice date for the VWAP Purchase. There are no limits on the number of VWAP purchases that the Company may require. The Aspire Stock Purchase Agreement may be terminated by the Company at any time, at the Company’s discretion, without any cost to the Company. There are no limitations on use of proceeds, financial or business covenants, restrictions on future financings, rights of first refusal, participation rights, penalties, or liquidated damages in the Aspire Stock Purchase Agreement. Common Stock Public Offering 2021 Public Offering In September 2021, the Company entered into an underwriting agreement (the “2021 Underwriting Agreement”) with Jeffries LLC, SVB Leerink LLC and Evercore Group, LLC (collectively, the “Underwriters”) for the sale and issuance of 7,344,543 shares of common stock, which includes 1,159,089 shares of common stock issued in connection with the exercise in full by the underwriters of their option to purchase additional shares, at a public offering price of $11.00 per share and 23,126 shares of Series B Non-Voting Convertible Preferred Stock at a public offering price of $733.37 per share (collectively the “2021 Public Offering”). The aggregate gross proceeds to the Company from the 2021 Public Offering are approximately $97.7 million, before deducting underwriting discounts and commissions and estimated offering expenses payable by the Company. Preferred Stock Under the Company’s second restated certificate of incorporation, the Company’s board of directors has the authority to designate and issue up to 5,000,000 shares of preferred stock, at its discretion, in one or more classes or series and to fix the powers, preferences and rights, and the qualifications, limitations, or restrictions thereof, including dividend rights, conversion rights, voting rights, terms of redemption, and liquidation preferences, without further vote or action by the Company’s stockholders. Series A Preferred Stock Holders of Series A Preferred Stock are entitled to receive dividends on shares of Series A Preferred Stock equal, on an as-if-converted-to-Common-Stock basis, and in the same form as dividends actually paid on shares of the common stock. Except as otherwise required by law, the Series A Preferred Stock does not have voting rights. However, as long as any shares of Series A Preferred Stock are outstanding, the Company will not, without the affirmative vote of the holders of a majority of the then outstanding shares of the Series A Preferred Stock, (i) alter or change adversely the powers, preferences or rights given to the Series A Preferred Stock, (ii) alter or amend the Certificate of Designation, (iii) amend its certificate of incorporation or other charter documents in any manner that adversely affects any rights of the holders of Series A Preferred Stock, (iv) increase the number of authorized shares of Series A Preferred Stock, (v) at any time while at least 30% of the originally issued Series A Preferred Stock remains issued and outstanding, consummate a Fundamental Transaction (as defined in the Certificate of Designation) or (vi) enter into any agreement with respect to any of the foregoing. The Series A Preferred Stock does not have a preference upon any liquidation, dissolution, or winding-up of the Company. Each share of Series A Preferred Stock is convertible into 66.67 shares of common stock at any time at the option of the holder thereof, subject to certain limitations, including that a holder of Series A Preferred Stock is prohibited from converting shares of Series A Preferred Stock into shares of common stock if, as a result of such conversion, such holder, together with its affiliates, would beneficially own more than a specified percentage (to be established by the holder between 4.99% and 19.99%) of the total number of shares of common stock issued and outstanding immediately after giving effect to such conversion. As of December 31, 2021, there were 260,437 shares of Series A Preferred Stock outstanding. During the three months ended March 31, 2022, 47,871 shares of Series A Preferred Stock were converted into 3,191,555 shares of common stock. As of March 31, 2022 there were 212,566 shares of Series A Preferred Stock outstanding. Series B Preferred Stock Each share of Series B Preferred Stock is convertible into 66.67 shares of common stock, subject to certain limitations, including that a holder of Series B Preferred Stock is prohibited from converting shares of Series B Preferred Stock into shares of common stock if, as a result of such conversion, such holder, together with its affiliates, would beneficially own more than a specified percentage (to be established by the holder between 4.9% and 19.9%) of the total number of shares of common stock issued and outstanding immediately after giving effect to such conversion. The powers, preferences, rights, qualifications, limitations, and restrictions applicable to the Series B Preferred Stock are set forth in the Certificate of Designation filed in connection with the Offering. Holders of Series B Preferred Stock are entitled to receive dividends on shares of Series B Preferred Stock equal, on an as-if-converted-to-Common-Stock basis, and in the same form as dividends actually paid on shares of the common stock. Except as otherwise required by law, the Series B Preferred Stock does not have voting rights. However, as long as any shares of Series B Preferred Stock are outstanding, the Company will not, without the affirmative vote of the holders of a majority of the then outstanding shares of the Series B Preferred Stock, (i) alter or change adversely the powers, preferences or rights given to the Series B Preferred Stock, (ii) alter or amend the Certificate of Designation, or (iii) amend its certificate of incorporation or other charter documents in any manner that adversely affects any rights of the holders of Series B Preferred Stock. The Series B Preferred Stock does not have a preference upon any liquidation, dissolution, or winding-up of the Company. As of December 31, 2021, there were 23,126 shares of Series B Preferred Stock outstanding. No shares of Series B Preferred Stock were converted into common stock during the three months ended March 31, 2022. The following table presents information about the Company’s outstanding warrants: Number of Underlying Shares (1) Weighted-Average Exercise Price at March 31, 2022 Remaining Contractual Life at March 31, 2022 March 31, December 31, Liability-classified warrants Issued April 2017 781 781 $127.95 3.08 Equity-classified warrants Acquired October 2020 29,446 29,446 $0.01 8.49 Issued February 2020 (2) 388,796 388,796 $15.28 2.87 Issued November 2017 1,606 1,606 $0.41 2.63 Subtotal 419,848 419,848 $15.70 Total warrants 420,629 420,629 $15.91 ____________________ (1) If the Company subdivides (by any stock split, stock dividend, recapitalization, or otherwise) its outstanding shares of its common stock into a smaller number of shares, the warrant exercise price is proportionately reduced and the number of shares under outstanding warrants is proportionately increased. Additionally, if the Company combines (by combination, reverse stock split, or otherwise) its outstanding shares of common stock into a smaller number of shares, the warrant exercise price is proportionately increased and the number of shares under outstanding warrants is proportionately decreased. (2) Subject to specified conditions, the Company may voluntarily reduce the warrant exercise price of the warrants issued in February 2020. There were no warrants exercised during the three months ended March 31, 2022.

SHARE-BASED COMPENSATION

SHARE-BASED COMPENSATION	3 Months Ended
	Mar. 31, 2022
Share-based Payment Arrangement [Abstract]
SHARE-BASED COMPENSATION	SHARE-BASED COMPENSATION Equity Incentive Plans The Company has grants outstanding under its 2008 Equity Incentive Plan (the “2008 Plan”), its amended and restated 2016 Equity Incentive Plan (the “2016 Plan”), and the Viridian 2020 Equity Incentive Plan (the “2020 Plan” and collectively with the 2008 Plan and the 2016 Plan, the “Equity Incentive Plans”). Additionally, beginning in July 2021, the Company granted stock options outside of its Equity Incentive Plans to certain employees to induce them to accept employment with the Company (the “Inducement Awards”). The terms and conditions of the Inducement Awards are substantially similar to those awards granted under the Company’s Equity Incentive Plans. As of March 31, 2022, the Company had the following balances by plan: Stock Options Outstanding Shares Available for Issuance Inducement Awards 720,000 — 2020 Plan 816,886 960,049 2016 Plan 3,264,312 30,289 2008 Plan 513 — Total 4,801,711 990,338 Options granted under the Equity Incentive Plans and the Inducement Awards have an exercise price equal to the market value of the common stock at the date of grant and expire 10 years from the date of grant. Generally, options vest 25% on the first anniversary of the vesting commencement date and 75% ratably in equal monthly installments over the remaining 36 months. The Company has also granted options that vest in equal monthly or quarterly amounts over periods up to 48 months. A summary of common stock option activity is as follows: Number of Options Weighted-Average Exercise Price Weighted-Average Remaining Contractual Term Aggregate Intrinsic Value Outstanding as of December 31, 2021 3,683,839 $16.94 8.94 $ 15,969 Granted 1,196,000 $18.54 — — Exercised (47,735) $13.98 — — Forfeited or expired (30,393) $20.68 — — Outstanding as of March 31, 2022 4,801,711 $17.34 9.05 $ 13,414 Outstanding as of March 31, 2022 - vested and expected to vest 4,801,711 $17.34 9.05 $ 13,414 Exercisable as of March 31, 2022 844,307 $17.00 7.99 $ 4,293 Fair Value Assumptions The Company uses the Black-Scholes option pricing model to estimate the fair value of stock options granted under its equity compensation plans. The Black-Scholes model requires inputs for risk-free interest rate, dividend yield, volatility, and expected lives of the options. Because the Company has a limited history of stock purchase and sale activity, expected volatility is based on historical data from public companies that are similar to the Company in size and nature of operations. The Company will continue to use similar entity volatility information until its historical volatility is relevant to measure expected volatility for option grants. The Company accounts for forfeitures as they occur. The risk-free rate for periods within the contractual life of each option is based on the U.S. Treasury yield curve in effect at the time of the grant for a period commensurate with the expected term of the grant. The expected term (without regard to forfeitures) for options granted represents the period of time that options granted are expected to be outstanding and is derived from the contractual terms of the options granted, and actual and expected option-exercise behaviors. The fair value of the underlying common stock is based on the closing price of the common stock on The Nasdaq Capital Market at the date of grant. Stock Options Granted The weighted-average grant-date fair value of options granted during the three months ended March 31, 2022 and 2021 was $13.43 and $19.56, respectively. The fair value was determined by the Black-Scholes option pricing model using the following weighted-average assumptions: Three Months Ended 2022 2021 Expected term, in years 5.81 5.90 Expected volatility 88.0% 126.2% Risk-free interest rate 1.63% 0.6% Expected dividend yield —% —% Weighted average exercise price $18.54 $22.33 Employee Stock Purchase Plan The 2016 Employee Stock Purchase Plan (“ESPP”) allows qualified employees to purchase shares of common stock at a price equal to 85% of the lower of: (i) the closing price at the beginning of the offering period or (ii) the closing price at the end of the offering period. New six-month offering periods begin each August 22 and February 22. As of March 31, 2022, the Company had 316,437 shares available for issuance, and 20,178 cumulative shares had been issued under the ESPP. Share-Based Compensation Expense Share-based compensation related to all equity awards issued pursuant to the Equity Incentive Plans, Inducement Plan, and for shares to be issued under the ESPP for the purchase periods active during each respective period is included in the condensed consolidated statements of operations and comprehensive loss as follows: Three Months Ended 2022 2021 (in thousands) Research and development $ 1,545 $ 1,111 General and administrative 3,114 2,064 Total share-based compensation expense $ 4,659 $ 3,175 As of March 31, 2022, the Company had $56.3 million of total unrecognized employee and non-employee share-based compensation costs, which the Company expects to recognize over a weighted-average remaining period of 3.18 years.

NET LOSS PER SHARE

NET LOSS PER SHARE	3 Months Ended
	Mar. 31, 2022
Earnings Per Share [Abstract]
NET LOSS PER SHARE	NET LOSS PER SHARE Basic net loss per share is computed by dividing the net loss available to common stockholders by the weighted-average number of common stock outstanding. Diluted net loss per share is computed similarly to basic net loss per share except that the denominator is increased to include the number of additional shares of common stock that would have been outstanding if the potential shares of common stock had been issued and if the additional shares of common stock were dilutive. Diluted net loss per share is the same as basic net loss per share of common stock, as the effects of potentially dilutive securities are antidilutive. Potentially dilutive securities include the following: March 31, 2022 2021 Series A Preferred Stock (as converted to shares of common stock) 14,171,775 23,656,049 Series B Preferred Stock (as converted to shares of common stock) 1,541,810 — Options to purchase common stock 4,801,711 3,153,624 Warrants to purchase common stock 420,629 441,545 Total 20,935,925 27,251,218

SUBSEQUENT EVENTS

SUBSEQUENT EVENTS	3 Months Ended
	Mar. 31, 2022
Subsequent Events [Abstract]
SUBSEQUENT EVENTS	SUBSEQUENT EVENTS Loan and Security Agreement On April 1, 2022, the Company entered into a loan and security agreement (the “Hercules Loan and Security Agreement”) among the Company, certain of its subsidiaries from time to time party thereto (together with the Company, collectively, the “Borrower”), Hercules Capital, Inc. (“Hercules”) and certain other lenders (the “Lenders”). Under the Hercules Loan and Security Agreement, the Lenders provided the Company with access to a term loan with an aggregate principal amount of up to $75.0 million, in four tranches (collectively the “Term Loan”), consisting of (1) an initial tranche of $25.0 million, available to the Company through June 15, 2023; (2) a second tranche of $10.0 million, subject to the achievement of certain regulatory milestones, available through June 15, 2023; (3) a third tranche of $15.0 million, subject to the achievement of certain regulatory milestones, available through March 15, 2024; and (4) a fourth tranche of $25.0 million, subject to approval by the Lenders’ investment committee(s), available through December 15, 2024. Upon signing the Company drew an initial principal amount of $5.0 million. The Term Loan bears interest at a floating per annum rate equal to the greater of (i) 7.45% and (ii) 4.2% above the Prime Rate, provided that the Term Loan interest rate shall not exceed a per annum rate of 8.95%. Interest is payable monthly in arrears on the first day of each month. The Company is obligated to make interest-only payments through April 1, 2024. If certain development milestones are met, then the interest-only period will be extended to October 1, 2024, or under a second extension if additional development milestones are met, to April 1, 2025. The obligations of the Borrower under the Loan Agreement are secured by substantially all of the assets of the Borrower, excluding the Borrower’s intellectual property. Second Amendment to Massachusetts Based Office Space Lease On April 13, 2022, the Company entered into a second amendment to the Original Lease of its Massachusetts-based office space (the “Second Amendment”). The Second Amendment makes certain modifications to both the Original Lease and Amended Lease, including (i) the addition of 2,432 square feet of office space in the same building (the “Expansion Premises”), (ii) the termination of the 1,087 square feet of leased space under the Original Lease seven days after the delivery of the Expansion Premises, and (iii) the extension of the expiration date of the 3,284 square feet of leased space under the Amended Lease to four years from the delivery of the Expansion Premises (the “Lease Term”). Under the Second Amendment, the Company has the option to extend the Lease Term for an additional period of three years (the “Option Term”), upon notice to the Landlord. The Second Amendment provides for annual base rent for the Expansion Premises of approximately $0.4 million during the Lease Term. The Company is also obligated to pay the Landlord certain costs, taxes and operating expenses.

SUMMARY OF SIGNIFICANT ACCOUN_2

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)	3 Months Ended
	Mar. 31, 2022
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying unaudited condensed consolidated financial statements have been prepared in conformity with U.S. generally accepted accounting principles (“U.S. GAAP”), for interim financial reporting and as required by Regulation S-X, Rule 10-01. Accordingly, they do not include all of the information and footnotes required by U.S. GAAP for complete financial statements. Any reference in these notes to applicable guidance is meant to refer to the authoritative U.S. GAAP as found in the Accounting Standards Codification (“ASC”), and Accounting Standards Update (“ASU”), or the Financial Accounting Standards Board (“FASB”). In the opinion of management, all adjustments, consisting of normal recurring accruals and revisions of estimates, considered necessary for a fair presentation of the unaudited condensed consolidated financial statements have been included. Interim results for the three months ended March 31, 2022, are not necessarily indicative of the results that may be expected for the fiscal year ending December 31, 2022, or any other future period. The accompanying unaudited condensed consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries. The Company’s subsidiaries have no employees or operations. All intercompany balances and transactions have been eliminated in consolidation. Management has determined that the Company operates in one segment, which is the business of developing and commercializing novel therapeutics. The information included in this Quarterly Report on Form 10-Q should be read in conjunction with the Company’s consolidated financial statements and the accompanying notes included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2021, filed with the U.S. Securities and Exchange Commission on March 11, 2022 (the “2021 Annual Report on Form 10-K”). The Company’s management performed an evaluation of its activities through the date of filing of these unaudited condensed consolidated financial statements and concluded that there are no subsequent events requiring disclosure, other than as disclosed.
Going Concern	Going Concern At each reporting period, the Company evaluates whether there are conditions or events that raise substantial doubt about the Company’s ability to continue as a going concern within one year after the date that the financial statements are issued. The Company is required to make certain additional disclosures if it concludes substantial doubt exists and it is not alleviated by the Company’s plans or when its plans alleviate substantial doubt about the Company’s ability to continue as a going concern. The Company’s evaluation entails, among other things, analyzing the results of the Company’s clinical development efforts, license and collaboration agreements as well as the entity’s current financial condition including conditional and unconditional obligations anticipated within a year, and related liquidity sources at the date the financial statements are issued. This is reflected in the Company’s prospective operating budgets and forecasts and compared to the current cash and cash equivalent balance.
Use of Estimates	Use of Estimates The Company’s condensed consolidated financial statements are prepared in accordance with U.S. GAAP, which requires it to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and contingent liabilities at the date of the financial statements and the reported amounts of revenue and expenses during the reporting period. Significant estimates and assumptions reflected in these condensed consolidated financial statements include, but are not limited to, the accrual for clinical trial costs and other outsourced research and development expenses, and the valuation of share-based awards. Although these estimates are based on the Company’s knowledge of current events and actions it may take in the future, actual results may ultimately differ from these estimates and assumptions.
Revenue Recognition	Revenue Recognition The Company accounts for revenue in accordance with ASC Topic 606, Revenue from Contracts with Customers (“ASC 606”). The Company enters into collaboration agreements and certain other agreements that are within the scope of ASC 606, under which the Company licenses, may license, or grants an option to license rights to certain of the Company’s product candidates and performs research and development services in connection with such agreements. The terms of these agreements typically include payment of one or more of the following: non-refundable, up-front fees; reimbursement of research and development costs; developmental, clinical, regulatory, and commercial sales milestone payments; and royalties on net sales of licensed products. In accordance with ASC 606, the Company recognizes revenue when its customer obtains control of promised goods or services, in an amount that reflects the consideration which the Company expects to receive in exchange for those goods or services. To determine the appropriate amount of revenue to be recognized, for agreements within the scope of ASC 606, the Company performs the following five steps: (i) identification of the goods or services within the contract; (ii) determination of whether the promised goods or services are performance obligations, including whether they are distinct within the terms of the contract; (iii) measurement of the transaction price, including the constraint on variable consideration; (iv) allocation of the transaction price to the identified performance obligations; and (v) recognition of revenue when (or as) the Company satisfies each performance obligation. The Company only applies the five-step model to contracts when it is probable that the Company will collect consideration it is entitled to in exchange for the goods or services it transfers to the customer. The promised goods or services in the Company’s agreements typically consist of a license, or option to license, rights to the Company’s intellectual property or research and development services. Performance obligations are promises in a contract to transfer a distinct good or service to the customer and are considered distinct when (i) the customer can benefit from the good or service on its own or together with other readily available resources and (ii) the promised good or service is separately identifiable from other promises in the contract. In assessing whether promised goods or services are distinct, the Company considers factors such as the stage of development of the underlying intellectual property, the capabilities of the customer to develop the intellectual property on its own or whether the required expertise is readily available, and whether the goods or services are integral or dependent to other goods or services in the contract. The Company estimates the transaction price based on the amount expected to be received for transferring the promised goods or services in the contract. The consideration may include fixed consideration or variable consideration. At the inception of each agreement that includes variable consideration, the Company evaluates the amount of potential payment and the likelihood that the payments will be received. The Company utilizes either the most likely amount method or expected value method to estimate the amount expected to be received based on which method best predicts the amount expected to be received. The amount of variable consideration that is included in the transaction price may be constrained and is included in the transaction price only to the extent that it is probable that a significant reversal in the amount of the cumulative revenue recognized will not occur in a future period. The Company’s contracts often include development and regulatory milestone payments that are assessed under the most likely amount method and constrained if it is probable that a significant revenue reversal would occur. Milestone payments that are not within the Company’s control or the licensee’s control, such as regulatory approvals, are not considered probable of being achieved until those approvals are received. At the end of each reporting period, the Company re-evaluates the probability of achievement of such development and clinical milestones and any related constraint, and if necessary, adjusts its estimate of the overall transaction price. Any such adjustments are recorded on a cumulative catch-up basis, which would affect collaboration and other research and development revenue in the period of adjustment. For agreements that include sales-based royalties, including milestone payments based on the level of sales, and the license is deemed to be the predominant item to which the royalties relate, the Company recognizes revenue at the later of (i) when the related sales occur, or (ii) when the performance obligation to which some or all of the royalty has been allocated has been satisfied (or partially satisfied). To date, the Company has not recognized any royalty revenue resulting from any of the Company’s collaboration or strategic alliance agreements. The Company allocates the transaction price based on the estimated standalone selling price. The Company must develop assumptions that require judgment to determine the stand-alone selling price for each performance obligation identified in the contract. The Company utilizes key assumptions to determine the stand-alone selling price, which may include other comparable transactions, pricing considered in negotiating the transaction, and the estimated costs. Variable consideration is allocated specifically to one or more performance obligations in a contract when the terms of the variable consideration relate to the satisfaction of the performance obligation and the resulting amounts allocated are consistent with the amounts the Company would expect to receive for the satisfaction of each performance obligation. The consideration allocated to each performance obligation is recognized as revenue when control is transferred for the related goods or services. For performance obligations which consist of licenses and other promises, the Company utilizes judgment to assess the nature of the combined performance obligation to determine whether the combined performance obligation is satisfied over time or at a point in time and, if over time, the appropriate method of measuring progress. The Company evaluates the measure of progress each reporting period and, if necessary, adjusts the measure of performance and related revenue recognition. The Company receives payments from its customers based on billing schedules established in each contract. Up-front payments and fees are recorded as deferred revenue upon receipt or when due until the Company performs its obligations under these arrangements. Amounts are recorded as accounts receivable when the Company’s right to consideration is unconditional.
Research and Development	Research and Development Research and development costs are expensed as incurred in performing research and development activities. The costs include employee-related expense including salaries, benefits, share-based compensation, restructuring charges, fees for acquiring and maintaining licenses under third-party license agreements, consulting fees, costs of research and development activities conducted by third parties on the Company’s behalf, costs to manufacture or have manufactured clinical trial materials, laboratory supplies, depreciation, and facilities and overhead costs. The Company records research and development expense in the period in which the Company receives or takes ownership of the applicable goods or when the applicable services are performed. In circumstances where amounts have been paid in excess of costs incurred, the Company records a prepaid expense. The Company records up-front and milestone payments to acquire and retain contractual rights to licensed technology as research and development expenses when incurred if there is uncertainty in the Company receiving future economic benefit from the acquired contractual rights. The Company considers future economic benefits from acquired contractual rights to licensed technology to be uncertain until such a drug candidate is approved for sale by the U.S. Food and Drug Administration or when other significant risk factors are abated.
Clinical Trials and Preclinical Study Accruals	Clinical Trial and Preclinical Study Accruals The Company makes estimates of accrued expenses as of each balance sheet date in its condensed consolidated financial statements based on certain facts and circumstances at that time. The Company’s accrued expenses for clinical trials and preclinical studies are based on estimates of costs incurred for services provided by clinical research organizations, manufacturing organizations, and other providers. Payments under the Company’s agreements with external service providers depend on a number of factors, such as site initiation, patient screening, enrollment, delivery of reports, and other events. In accruing for these activities, the Company obtains information from various sources and estimates the level of effort or expense allocated to each period. Adjustments to the Company’s research and development expenses may be necessary in future periods as its estimates change.
Share-Based Compensation	Share-Based Compensation The Company accounts for share-based compensation expense to employees and non-employees based on the fair value of each stock option or award on the date of the grant. The Company uses the Black-Scholes option pricing model to determine the fair value of stock options. The use of the Black-Scholes option-pricing model requires the Company to make assumptions with respect to the expected term of the option, the expected volatility of the common stock consistent with the expected life of the option, risk-free interest rates and expected dividend yields of the common stock. The Company recognizes share-based compensation expense for awards with service-based conditions using the straight-line method over the requisite service period, net of any actual forfeitures.
Cash and Cash Equivalents	Cash and Cash Equivalents All highly-liquid investments that have maturities of 90 days or less at the date of purchase are classified as cash equivalents. Cash equivalents are reported at cost, which approximates fair value due to the short maturities of these instruments.
Investments	Investments The Company has designated its investments as available-for-sale securities and accounts for them at their respective fair values. The securities are classified as short-term or long-term based on the nature of the securities and their availability to meet current operating requirements. Securities that are readily available for use in current operations are classified as short-term available-for-sale securities and are reported as a component of current assets in the accompanying condensed consolidated balance sheets. Securities that are classified as available-for-sale are measured at fair value, including accrued interest, with temporary unrealized gains and losses reported as a component of stockholders’ equity until their disposition. The Company reviews available-for-sale securities at the end of each period to determine whether they remain available-for-sale based on its then-current intent. The cost of securities sold is based on the specific identification method. The securities are subject to a periodic impairment review. An impairment charge would occur when a decline in the fair value of the investments below the cost basis is judged to be other-than-temporary.
Fair Value Measurements and Fair Value of Financial Instruments	Fair Value Measurements Certain assets and liabilities are carried at fair value under GAAP. Fair value is defined as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. Valuation techniques used to measure fair value must maximize the use of observable inputs and minimize the use of observable in puts. Financial assets and liabilities carried at fair value are to be classified and disclosed in one of the following three levels of the fair value hierarchy, of which the first two are considered observable and the last is considered unobservable: • Level 1 inputs utilize quoted prices (unadjusted) in active markets for identical assets or liabilities. • Level 2 inputs utilizes observable inputs other than Level 1 prices, such as quoted prices, for similar assets or liabilities, quoted market prices in markets that are not active, or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the related assets or liabilities. • Level 3 inputs are unobservable data points for the asset or liability and include situations where there is little, if any, market activity for the asset or liability. Certain of the Company’s financial instruments are not measured at fair value on a recurring basis but are recorded at amounts that approximate their fair value due to the short-term nature of their maturities, such as cash and cash equivalents, accounts receivable, accounts payable, and accrued expenses. The Company accounts for warrants to purchase its common stock pursuant to ASC Topic 470, Debt , and ASC Topic 480, Distinguishing Liabilities from Equity , and classifies warrants for common stock as liabilities or equity. The warrants classified as liabilities are reported at their estimated fair value (see Note 3. Fair Value Measurements ) and any changes in fair value are reflected in interest and other expense. The warrants classified as equity are reported at their estimated fair value with no subsequent remeasurement. The Company’s outstanding warrants are discussed in more detail in Note 8. Warrants . Fair Value of Financial Instruments Certain of the Company’s financial instruments are not measured at fair value on a recurring basis but are recorded at amounts that approximate their fair value due to the short-term nature of their maturities, such as cash and cash equivalents, accounts receivable, accounts payable, and accrued expenses. The Company accounts for warrants to purchase its stock pursuant to ASC Topic 470, Debt , and ASC Topic 480, Distinguishing Liabilities from Equity
Concentrations of Credit Risk	Concentrations of Credit Risk Financial instruments that potentially subject the Company to concentrations of credit risk consist primarily of cash equivalents, which include short-term investments that have maturities of less than three months. 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. The Company invests its excess cash primarily in deposits and money market funds held with one financial institution.
Property and Equipment	Property and Equipment The Company carries its property and equipment at cost, less accumulated depreciation and amortization. Depreciation is computed using the straight-line method over the estimated useful lives of the assets, generally three
Operating Lease Right-of-Use Asset	Operating Lease Right-of-Use Asset The Company determines if an arrangement is, or contains, a lease at contract inception and during modifications or renewal of existing leases. Operating lease assets represent the Company’s right to use an underlying asset for the lease term and operating lease liabilities represent the Company’s obligation to make lease payments arising from the lease. The Company has recorded operating lease assets and liabilities pursuant to the guidance in Accounting Standards Update (“ASU”) No. 2016-02 , Leases (Topic 842),
Convertible Preferred Stock	Convertible Preferred Stock The Company records shares of non-voting convertible preferred stock at their respective fair values on the dates of issuance, net of issuance costs. The Company has applied the guidance in ASC 480-10-S99-3A, SEC Staff Announcement: Classification and Measurement of Redeemable Securities , and at issuance classified the Series A Preferred Stock outside of stockholders’ equity because, if convertibility of Series A Preferred Stock into common stock was not approved by the stockholders, the Series A Preferred Stock would be redeemable at the option of the holders for cash equal to the closing price of the common stock on last trading day prior to the holder’s redemption request. On December 31, 2020, the stockholders approved the convertibility of the Series A Preferred Stock into common stock and as such, the Company reclassified the Series A Preferred Stock to permanent equity. In September 2021, the Company issued Series B Preferred Stock with conversion rights which the Company has classified as permanent equity.
Impairment of Long-Lived Assets	Impairment of Long-Lived AssetsThe Company assesses the carrying amount of its property and equipment whenever events or changes in circumstances indicate the carrying amount of such assets may not be recoverable.
Net Loss per Share	Net Loss per Share Basic net loss per share is calculated by dividing the net loss by the weighted-average number of shares of common stock outstanding during the period without consideration of common stock equivalents. Since the Company was in a loss position for all periods presented, diluted net loss per share is the same as basic net loss per share for all periods, as the inclusion of all potential common shares outstanding is antidilutive.
Comprehensive Loss	Comprehensive LossComprehensive loss is comprised of net loss and adjustments for the change in unrealized gains and losses on investments. Unrealized accumulated comprehensive gains or losses are reflected as a separate component in the condensed consolidated statements of changes in stockholders’ equity.
Income Taxes	Income Taxes The Company accounts for income taxes by using an asset and liability method of accounting for deferred income taxes. Deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases. A valuation allowance is recorded to the extent it is more likely than not that a deferred tax asset will not be realized. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in operations in the period that includes the enactment date. The Company’s significant deferred tax assets are for net operating loss carryforwards, tax credits, accruals and reserves, and capitalized start-up costs. The Company has provided a valuation allowance for its entire net deferred tax assets since inception as, due to its history of operating losses, the Company has concluded that it is more likely than not that its deferred tax assets will not be realized.
Warrants	Warrants Upon the issuance of warrants to purchase shares of common stock, the Company evaluates the terms of the warrant issue to determine the appropriate accounting and classification of the warrant issue pursuant to FASB ASC Topic 480, Distinguishing Liabilities from Equity , FASB ASC Topic 505, Equity , FASB ASC 815, Derivatives and Hedging, and ASC 718, Compensation - Stock Compensation . Warrants are classified as liabilities when the Company may be required to settle a warrant exercise in cash and classified as equity when the Company settles a warrant exercise in shares of its common stock. Liability-classified warrants are valued at fair value at the date of issue and at each reporting date pursuant to FASB ASC 820, Fair Value Measurement , and are reflected as a warrant liability on the Company’s condensed consolidated balance sheets. Any changes in the warrant liability during each reporting period would be reflected as other expense in the condensed consolidated statement of operations and comprehensive loss.
Segment Information	Segment Information The Company operates in one operating segment and, accordingly, no segment disclosures have been presented herein. All equipment, leasehold improvements, and other fixed assets are physically located within the United States and all agreements with the Company’s partners are denominated in U.S. dollars, except where noted.
Recent Accounting Pronouncements - To Be Adopted	Recent Accounting Pronouncements – To Be Adopted From time to time, new accounting pronouncements are issued by the FASB or other standard setting bodies that the Company adopts as of the specified effective date. The Company does not believe that the adoption of recently issued standards have or may have a material impact on the Company’s consolidated financial statements or disclosures.

FAIR VALUE MEASUREMENTS (Tables

FAIR VALUE MEASUREMENTS (Tables)	3 Months Ended
	Mar. 31, 2022
Fair Value Disclosures [Abstract]
Schedule of Debt Securities, Available-for-sale	The following table provides details regarding the Company’s short-term investments: (in thousands) Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value March 31, 2022 Money market funds $ 30,758 $ — $ — $ 30,758 U.S. treasury securities 27,358 1 (252) 27,107 U.S. corporate paper and bonds 113,562 — (639) 112,923 International corporate bond holdings 4,585 — (45) 4,540 Total $ 176,263 $ 1 $ (936) $ 175,328 December 31, 2021 Money market funds $ 42,199 $ — $ — $ 42,199 U.S. treasury securities 22,215 — (54) 22,161 U.S. corporate paper and bonds 128,005 6 (94) 127,917 International corporate bond holdings 4,603 — (15) 4,588 Total $ 197,022 $ 6 $ (163) $ 196,865 The money market funds above are included in cash and cash equivalents on the Company’s condensed consolidated balance sheets.
Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis	The following tables summarize the Company’s assets and liabilities that are measured at fair value on a recurring basis: (in thousands) Quoted Prices in Active Markets Significant Other Observable Inputs Significant Unobservable Inputs Total March 31, 2022 Assets: Cash equivalents: Money market funds $ 30,758 $ — $ — $ 30,758 Short-term investments: U.S. treasury securities — 27,109 — 27,109 U.S. corporate paper and bonds — 112,923 — 112,923 International corporate bond holdings — 4,538 — 4,538 Total cash equivalents and short-term investments $ 30,758 $ 144,570 $ — $ 175,328 December 31, 2021 Assets: Cash equivalents: Money market funds $ 42,199 $ — $ — $ 42,199 Short-term investments: U.S. treasury securities — 22,161 — 22,161 U.S. corporate paper and bonds — 127,917 — 127,917 International corporate bond holdings — 4,588 — 4,588 Total cash equivalents and short-term investments $ 42,199 $ 154,666 $ — $ 196,865

ACCRUED LIABILITIES (Tables)

ACCRUED LIABILITIES (Tables)	3 Months Ended
	Mar. 31, 2022
Payables and Accruals [Abstract]
Schedule of Components of Accrued Liabilities	Accrued liabilities consisted of the following: March 31, December 31, (in thousands) Accrued outsourced clinical trials and preclinical studies $ 8,647 $ 6,316 Accrued employee compensation and related taxes 1,548 3,652 Operating lease liability, short-term 579 520 Accrued legal fees and expenses 272 80 Accrued other professional service fees 131 140 Value of liability-classified stock purchase warrants 100 100 Other accrued liabilities 283 210 $ 11,560 $ 11,018

WARRANTS (Tables)

WARRANTS (Tables)	3 Months Ended
	Mar. 31, 2022
Other Liabilities Disclosure [Abstract]
Schedule of Warrants	The following table presents information about the Company’s outstanding warrants: Number of Underlying Shares (1) Weighted-Average Exercise Price at March 31, 2022 Remaining Contractual Life at March 31, 2022 March 31, December 31, Liability-classified warrants Issued April 2017 781 781 $127.95 3.08 Equity-classified warrants Acquired October 2020 29,446 29,446 $0.01 8.49 Issued February 2020 (2) 388,796 388,796 $15.28 2.87 Issued November 2017 1,606 1,606 $0.41 2.63 Subtotal 419,848 419,848 $15.70 Total warrants 420,629 420,629 $15.91 ____________________ (1) If the Company subdivides (by any stock split, stock dividend, recapitalization, or otherwise) its outstanding shares of its common stock into a smaller number of shares, the warrant exercise price is proportionately reduced and the number of shares under outstanding warrants is proportionately increased. Additionally, if the Company combines (by combination, reverse stock split, or otherwise) its outstanding shares of common stock into a smaller number of shares, the warrant exercise price is proportionately increased and the number of shares under outstanding warrants is proportionately decreased. (2) Subject to specified conditions, the Company may voluntarily reduce the warrant exercise price of the warrants issued in February 2020.

SHARE-BASED COMPENSATION (Table

SHARE-BASED COMPENSATION (Tables)	3 Months Ended
	Mar. 31, 2022
Share-based Payment Arrangement [Abstract]
Schedule of Summary of Balances by Plan	As of March 31, 2022, the Company had the following balances by plan: Stock Options Outstanding Shares Available for Issuance Inducement Awards 720,000 — 2020 Plan 816,886 960,049 2016 Plan 3,264,312 30,289 2008 Plan 513 — Total 4,801,711 990,338
Schedule of Stock Option Activity	A summary of common stock option activity is as follows: Number of Options Weighted-Average Exercise Price Weighted-Average Remaining Contractual Term Aggregate Intrinsic Value Outstanding as of December 31, 2021 3,683,839 $16.94 8.94 $ 15,969 Granted 1,196,000 $18.54 — — Exercised (47,735) $13.98 — — Forfeited or expired (30,393) $20.68 — — Outstanding as of March 31, 2022 4,801,711 $17.34 9.05 $ 13,414 Outstanding as of March 31, 2022 - vested and expected to vest 4,801,711 $17.34 9.05 $ 13,414 Exercisable as of March 31, 2022 844,307 $17.00 7.99 $ 4,293
Schedule of Fair Value Assumptions for Stock Options	The fair value was determined by the Black-Scholes option pricing model using the following weighted-average assumptions: Three Months Ended 2022 2021 Expected term, in years 5.81 5.90 Expected volatility 88.0% 126.2% Risk-free interest rate 1.63% 0.6% Expected dividend yield —% —% Weighted average exercise price $18.54 $22.33
Schedule of Allocation of Share-based Compensation Expense	Share-based compensation related to all equity awards issued pursuant to the Equity Incentive Plans, Inducement Plan, and for shares to be issued under the ESPP for the purchase periods active during each respective period is included in the condensed consolidated statements of operations and comprehensive loss as follows: Three Months Ended 2022 2021 (in thousands) Research and development $ 1,545 $ 1,111 General and administrative 3,114 2,064 Total share-based compensation expense $ 4,659 $ 3,175

NET LOSS PER SHARE (Tables)

NET LOSS PER SHARE (Tables)	3 Months Ended
	Mar. 31, 2022
Earnings Per Share [Abstract]
Schedule of Potentially Dilutive Securities	Potentially dilutive securities include the following: March 31, 2022 2021 Series A Preferred Stock (as converted to shares of common stock) 14,171,775 23,656,049 Series B Preferred Stock (as converted to shares of common stock) 1,541,810 — Options to purchase common stock 4,801,711 3,153,624 Warrants to purchase common stock 420,629 441,545 Total 20,935,925 27,251,218

DESCRIPTION OF BUSINESS (Detail

DESCRIPTION OF BUSINESS (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Accumulated deficit	$ 383,993	$ 358,300
Cash, cash equivalents and short-term investments	$ 175,400

SUMMARY OF SIGNIFICANT ACCOUN_3

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Narrative (Details)	3 Months Ended
	Mar. 31, 2022USD ($)segment	Mar. 31, 2021USD ($)
Property, Plant and Equipment [Line Items]
Number of operating segments | segment	1
Impairment charges	$ 0	$ 0
Unrecognized tax benefits	0
Income tax penalties and interest expense	$ 0	$ 0
Minimum
Property, Plant and Equipment [Line Items]
Estimated useful lives	3 years
Maximum
Property, Plant and Equipment [Line Items]
Estimated useful lives	5 years

FAIR VALUE MEASUREMENTS - Debt

FAIR VALUE MEASUREMENTS - Debt Securities, Available-for-sale (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 176,263	$ 197,022
Gross Unrealized Gains	1	6
Gross Unrealized Losses	(936)	(163)
Fair Value	175,328	196,865
Money market funds
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	30,758	42,199
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Fair Value	30,758	42,199
U.S. treasury securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	27,358	22,215
Gross Unrealized Gains	1	0
Gross Unrealized Losses	(252)	(54)
Fair Value	27,107	22,161
U.S. corporate paper and bonds
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	113,562	128,005
Gross Unrealized Gains	0	6
Gross Unrealized Losses	(639)	(94)
Fair Value	112,923	127,917
International corporate bond holdings
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	4,585	4,603
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(45)	(15)
Fair Value	$ 4,540	$ 4,588

FAIR VALUE MEASUREMENTS - Narra

FAIR VALUE MEASUREMENTS - Narrative (Details) - USD ($)	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Fair Value Disclosures [Abstract]
Realized gains in available for sale securities	$ 0	$ 4,000
Available-for-sale securities, term	24 months

FAIR VALUE MEASUREMENTS - Fair

FAIR VALUE MEASUREMENTS - Fair Value, Assets and Liabilities Measured on Recurring Basis (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Short-term investments:
Short-term investments	$ 175,328	$ 196,865
Money market funds
Short-term investments:
Short-term investments	30,758	42,199
U.S. treasury securities
Short-term investments:
Short-term investments	27,107	22,161
U.S. corporate paper and bonds
Short-term investments:
Short-term investments	112,923	127,917
International corporate bond holdings
Short-term investments:
Short-term investments	4,540	4,588
Fair Value, Recurring
Short-term investments:
Total cash equivalents and short-term investments	175,328	196,865
Fair Value, Recurring | Money market funds
Cash equivalents:
Money market funds	30,758	42,199
Fair Value, Recurring | U.S. treasury securities
Short-term investments:
Short-term investments	27,109	22,161
Fair Value, Recurring | U.S. corporate paper and bonds
Short-term investments:
Short-term investments	112,923	127,917
Fair Value, Recurring | International corporate bond holdings
Short-term investments:
Short-term investments	4,538	4,588
Fair Value, Recurring | Quoted Prices in Active Markets (Level 1)
Short-term investments:
Total cash equivalents and short-term investments	30,758	42,199
Fair Value, Recurring | Quoted Prices in Active Markets (Level 1) | Money market funds
Cash equivalents:
Money market funds	30,758	42,199
Fair Value, Recurring | Quoted Prices in Active Markets (Level 1) | U.S. treasury securities
Short-term investments:
Short-term investments	0	0
Fair Value, Recurring | Quoted Prices in Active Markets (Level 1) | U.S. corporate paper and bonds
Short-term investments:
Short-term investments	0	0
Fair Value, Recurring | Quoted Prices in Active Markets (Level 1) | International corporate bond holdings
Short-term investments:
Short-term investments	0	0
Fair Value, Recurring | Significant Other Observable Inputs (Level 2)
Short-term investments:
Total cash equivalents and short-term investments	144,570	154,666
Fair Value, Recurring | Significant Other Observable Inputs (Level 2) | Money market funds
Cash equivalents:
Money market funds	0	0
Fair Value, Recurring | Significant Other Observable Inputs (Level 2) | U.S. treasury securities
Short-term investments:
Short-term investments	27,109	22,161
Fair Value, Recurring | Significant Other Observable Inputs (Level 2) | U.S. corporate paper and bonds
Short-term investments:
Short-term investments	112,923	127,917
Fair Value, Recurring | Significant Other Observable Inputs (Level 2) | International corporate bond holdings
Short-term investments:
Short-term investments	4,538	4,588
Fair Value, Recurring | Significant Unobservable Inputs (Level 3)
Short-term investments:
Total cash equivalents and short-term investments	0	0
Fair Value, Recurring | Significant Unobservable Inputs (Level 3) | Money market funds
Cash equivalents:
Money market funds	0	0
Fair Value, Recurring | Significant Unobservable Inputs (Level 3) | U.S. treasury securities
Short-term investments:
Short-term investments	0	0
Fair Value, Recurring | Significant Unobservable Inputs (Level 3) | U.S. corporate paper and bonds
Short-term investments:
Short-term investments	0	0
Fair Value, Recurring | Significant Unobservable Inputs (Level 3) | International corporate bond holdings
Short-term investments:
Short-term investments	$ 0	$ 0

ACCRUED LIABILITIES - Component

ACCRUED LIABILITIES - Components of Accrued Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021	Oct. 31, 2020
Payables and Accruals [Abstract]
Accrued outsourced clinical trials and preclinical studies	$ 8,647	$ 6,316
Accrued employee compensation and related taxes	1,548	3,652
Operating lease liability, short-term	579	520	$ 100
Accrued legal fees and expenses	272	80
Accrued other professional service fees	131	140
Value of liability-classified stock purchase warrants	100	100
Other accrued liabilities	283	210
Accrued Liabilities, Current, Total	$ 11,560	$ 11,018
Operating lease, liability, current, statement of financial position [Extensible List]	Accrued Liabilities, Current, Total	Accrued Liabilities, Current, Total

COLLABORATION AGREEMENTS (Detai

COLLABORATION AGREEMENTS (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Apr. 30, 2021
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Revenue	$ 216	$ 1,451
Zenas BioPharma | Fairmount Funds Management
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Noncontrolling interest ownership percentage	5.00%
Paragon Therapeutics
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Collaborative arrangement, upfront fee payment	$ 2,500
Paragon Therapeutics | Fairmount Funds Management
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Noncontrolling interest ownership percentage	5.00%		5.00%
Collaboration revenue - related party | Zenas BioPharma
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Revenue	$ 200	$ 1,500

COMMITMENTS AND CONTINGENCIES (

COMMITMENTS AND CONTINGENCIES (Details)	1 Months Ended	3 Months Ended		12 Months Ended
	Dec. 31, 2021USD ($)shares	Mar. 31, 2022USD ($)renewal_term	Mar. 31, 2021USD ($)	Dec. 31, 2021USD ($)shares	Dec. 31, 2020USD ($)shares	Apr. 30, 2021USD ($)	Oct. 31, 2020USD ($)
Commitments and Contingencies [Line Items]
Number of renewal terms (up to) | renewal_term		3
Lessee, operating lease, renewal term		3 years
Operating lease liability noncurrent		$ 1,100,000
Operating lease right-of-use asset	$ 1,680,000	1,543,000	$ 1,600,000	$ 1,680,000			$ 100,000
Lease discount rate			6.00%				6.00%
Lease remaining term			12 months
Operating sublease receivables						$ 200,000
Operating lease liability, short-term	$ 520,000	579,000		$ 520,000			$ 100,000
Future lease payments due		$ 1,800,000
Operating lease, liability, current, statement of financial position [Extensible List]	Accrued liabilities	Accrued liabilities		Accrued liabilities
Operating lease, liability, noncurrent, statement of financial position [Extensible List]		Other liabilities
Amortization (reversal of amortization) expense relating to operating lease right-of-use assets		$ 100,000	$ 100,000
Operating expenses of leases		$ 51,000	$ 54,000
Paragon Therapeutics | Fairmount Funds Management
Commitments and Contingencies [Line Items]
Noncontrolling interest ownership percentage		5.00%				5.00%
ImmunoGen, Inc
Commitments and Contingencies [Line Items]
Milestone payments							48,000,000
Collaborative arrangement, milestone payment	$ 2,500,000
Potential royalty payments							$ 95,000,000
Xencor, Inc
Commitments and Contingencies [Line Items]
Milestone payments	27,800,000			$ 27,800,000	$ 30,000,000
Potential royalty payments	$ 20,000,000			$ 20,000,000	$ 25,000,000
Collaboration arrangement, research license and selection rights, term	1 year
Shares issued in exchange for rights granted (in shares) | shares	394,737			394,737	322,407
Value of shares issued in exchange for rights granted				$ 7,500,000	$ 6,000,000
Collaboration arrangement, potential development milestone payment, maximum	$ 4,800,000			4,800,000
Collaborative arrangement, potential special payments, maximum	$ 3,000,000			$ 3,000,000

CAPITAL STOCK (Details)

CAPITAL STOCK (Details)	Mar. 31, 2022vote$ / sharesshares	Nov. 30, 2021USD ($)	Sep. 30, 2021USD ($)$ / sharesshares	Apr. 30, 2021USD ($)	Dec. 31, 2019shares	Mar. 31, 2022closingvote$ / sharesshares	Dec. 31, 2021USD ($)$ / sharesshares	Dec. 31, 2021$ / sharesshares	Dec. 31, 2020USD ($)$ / sharesshares
Class of Stock [Line Items]
Shares authorized (in shares)	205,000,000					205,000,000
Common stock, shares authorized (in shares)	200,000,000					200,000,000	200,000,000	200,000,000
Preferred stock, shares authorized (in shares)	5,000,000					5,000,000
Preferred stock, par value (in dollars per share) | $ / shares	$ 0.01					$ 0.01
Common stock, par value (in dollars per share) | $ / shares	$ 0.01					$ 0.01	$ 0.01	$ 0.01
Common stock, vote per share | vote	1					1
Series A Preferred Stock (as converted to shares of common stock)
Class of Stock [Line Items]
Preferred stock, shares authorized (in shares)	435,000					435,000	435,000	435,000
Preferred stock, par value (in dollars per share) | $ / shares	$ 0.01					$ 0.01	$ 0.01	$ 0.01
Preferred stock outstanding (in shares)	212,566					212,566	260,437	260,437
Series B Preferred Stock (as converted to shares of common stock)
Class of Stock [Line Items]
Preferred stock, shares authorized (in shares)	500,000					500,000	500,000	500,000
Preferred stock, par value (in dollars per share) | $ / shares	$ 0.01					$ 0.01	$ 0.01	$ 0.01
Preferred stock outstanding (in shares)	23,126					23,126	23,126	23,126
Common Stock
Class of Stock [Line Items]
Number of securities called by each warrant or right (in shares)	66.67					66.67
Common Stock | Series A Preferred Stock (as converted to shares of common stock) | Series A Preferred Stock Conversion
Class of Stock [Line Items]
Conversion of stock, shares issued (in shares)						3,191,555
Preferred Stock | Series A Preferred Stock (as converted to shares of common stock) | Series A Preferred Stock Conversion
Class of Stock [Line Items]
Conversion of stock, shares converted (in shares)						47,871
Preferred Stock | Series B Preferred Stock (as converted to shares of common stock) | Series B Preferred Stock Conversion
Class of Stock [Line Items]
Conversion of stock, shares converted (in shares)						0
Viridian Merger | Common Stock
Class of Stock [Line Items]
Number of securities called by each warrant or right (in shares)	66.67					66.67
Beneficial ownership	30.00%					30.00%
Maximum | Common Stock | Series B Preferred Stock (as converted to shares of common stock)
Class of Stock [Line Items]
Beneficial ownership	19.90%					19.90%
Maximum | Viridian Merger | Common Stock
Class of Stock [Line Items]
Beneficial ownership	19.99%					19.99%
Minimum | Common Stock | Series B Preferred Stock (as converted to shares of common stock)
Class of Stock [Line Items]
Beneficial ownership	4.90%					4.90%
Minimum | Viridian Merger | Common Stock
Class of Stock [Line Items]
Beneficial ownership	4.99%					4.99%
ATM Agreement
Class of Stock [Line Items]
Aggregate offering | $		$ 75,000,000		$ 50,000,000
Commission fee percent		3.00%		3.00%
Shares sold (in shares)	0
ATM Agreement | Common Stock
Class of Stock [Line Items]
Shares sold (in shares)							2,551,269
Weighted-average share price (in dollars per share) | $ / shares							$ 13.13
Proceeds from issuance of common stock | $							$ 32,400,000
Aspire Stock Purchase Agreement
Class of Stock [Line Items]
Shares sold (in shares)								0	412,187
Weighted-average share price (in dollars per share) | $ / shares									$ 21.35
Transaction value | $									$ 8,800,000
Amount of shares authorized to be sold (in shares)					20,000,000	10,200,000
Sale of stock, term					30 months
Average over number of lowest sale prices | closing						3
Number of consecutive days threshold						10 days
Aspire Stock Purchase Agreement | Common Stock
Class of Stock [Line Items]
Amount of shares required to be purchased (in shares)						13,333
Additional trading volume available for purchase, percent						30.00%
Price of additional share, percent of next business days' volume weighted average price						97.00%
Public Stock Offering
Class of Stock [Line Items]
Aggregate offering | $			$ 97,700,000
Public Stock Offering | Series B Preferred Stock (as converted to shares of common stock)
Class of Stock [Line Items]
Shares sold (in shares)			23,126
Sale of stock price (in dollars per share) | $ / shares			$ 733.37
Public Stock Offering | Common Stock
Class of Stock [Line Items]
Shares sold (in shares)			7,344,543
Sale of stock price (in dollars per share) | $ / shares			$ 11
Over-Allotment Option | Common Stock
Class of Stock [Line Items]
Shares sold (in shares)			1,159,089

WARRANTS - Stock Warrants Outst

WARRANTS - Stock Warrants Outstanding (Details) - $ / shares	3 Months Ended
	Mar. 31, 2022	Dec. 31, 2021
Class of Warrant or Right [Line Items]
Number of underlying shares (in shares)	420,629	420,629
Weighted average exercise price (in dollars per share)	$ 15.91
Exercised (in shares)	0
Issued April 2017
Class of Warrant or Right [Line Items]
Number of underlying shares (in shares)	781	781
Weighted average exercise price (in dollars per share)	$ 127.95
Remaining contractual life	3 years 29 days
Acquired October 2020
Class of Warrant or Right [Line Items]
Number of underlying shares (in shares)	29,446	29,446
Weighted average exercise price (in dollars per share)	$ 0.01
Remaining contractual life	8 years 5 months 26 days
Issued February 2020
Class of Warrant or Right [Line Items]
Number of underlying shares (in shares)	388,796	388,796
Weighted average exercise price (in dollars per share)	$ 15.28
Remaining contractual life	2 years 10 months 13 days
Issued November 2017
Class of Warrant or Right [Line Items]
Number of underlying shares (in shares)	1,606	1,606
Weighted average exercise price (in dollars per share)	$ 0.41
Remaining contractual life	2 years 7 months 17 days
Subtotal
Class of Warrant or Right [Line Items]
Number of underlying shares (in shares)	419,848	419,848
Weighted average exercise price (in dollars per share)	$ 15.70

SHARE-BASED COMPENSATION - Bala

SHARE-BASED COMPENSATION - Balance by Plan (Details)	Mar. 31, 2022shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options outstanding (in shares)	4,801,711
Shares available for issuance (in shares)	990,338
Inducement Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options outstanding (in shares)	720,000
Shares available for issuance (in shares)	0
2020 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options outstanding (in shares)	816,886
Shares available for issuance (in shares)	960,049
2016 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options outstanding (in shares)	3,264,312
Shares available for issuance (in shares)	30,289
2008 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options outstanding (in shares)	513
Shares available for issuance (in shares)	0

SHARE-BASED COMPENSATION - Narr

SHARE-BASED COMPENSATION - Narrative (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		75 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Mar. 31, 2022
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized employee stock-based compensation costs	$ 56.3		$ 56.3
Remaining weighted-average period for RSUs	3 years 2 months 4 days
Common Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Purchase price of common stock, percentage of fair market value	85.00%
Stock purchase offering period	6 months
Number of shares available for issuance under ESPP (in shares)	316,437		316,437
Issuance of common stock for cash under employee stock purchase plan (in shares)	6,128	980	20,178
Options to Purchase Common Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expiration period	10 years
Vesting period (up to)	48 months
Weighted average fair value per option (in usd per share)	$ 13.43	$ 19.56
Options to Purchase Common Stock | Initial Vesting Period
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percent	25.00%
Options to Purchase Common Stock | Subsequent Vesting Period
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percent	75.00%
Vesting period (up to)	36 months

SHARE-BASED COMPENSATION - Stoc

SHARE-BASED COMPENSATION - Stock Option Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2022	Dec. 31, 2021
Number of Options
Ending balance (in shares)	4,801,711
Options to purchase common stock
Number of Options
Beginning balance (in shares)	3,683,839
Granted (in shares)	1,196,000
Exercised (in shares)	(47,735)
Forfeited or expired (in shares)	(30,393)
Ending balance (in shares)	4,801,711	3,683,839
Vested or expected to vest (in shares)	4,801,711
Exercisable (in shares)	844,307
Weighted-Average Exercise Price
Beginning balance (in dollars per share)	$ 16.94
Granted (in dollars per share)	18.54
Exercised (in dollars per share)	13.98
Forfeited or expired (in dollars per share)	20.68
Ending balance (in dollars per share)	17.34	$ 16.94
Vested and expected to vest (in dollars per share)	17.34
Exercisable (in dollars per share)	$ 17
Weighted average remaining contractual term and Aggregate intrinsic value
Outstanding (Weighted Average Remaining Contractual Term)	9 years 18 days	8 years 11 months 8 days
Exercisable (Weighted Average Remaining Contractual Term)	7 years 11 months 26 days
Outstanding (Aggregate Intrinsic Value)	$ 13,414	$ 15,969
Vested and expected to vest (Aggregate Intrinsic Value)	13,414	$ 15,969
Exercisable (Aggregate Intrinsic Value)	4,293
Vested (Aggregate Intrinsic Value)	$ 4,293

SHARE-BASED COMPENSATION - Fair

SHARE-BASED COMPENSATION - Fair Value Assumption for Stock Options (Details) - Options to purchase common stock - $ / shares	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term, in years	5 years 9 months 21 days	5 years 10 months 24 days
Expected volatility	88.00%	126.20%
Risk-free interest rate	1.63%	0.60%
Expected dividend yield	0.00%	0.00%
Weighted-average exercise price (in dollars per share)	$ 18.54	$ 22.33

SHARE-BASED COMPENSATION - Allo

SHARE-BASED COMPENSATION - Allocation of Share-based Compensation Expense on Statements of Operations (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total share-based compensation expense	$ 4,659	$ 3,175
Research and development
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total share-based compensation expense	1,545	1,111
General and administrative
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total share-based compensation expense	$ 3,114	$ 2,064

NET LOSS PER SHARE - Potential

NET LOSS PER SHARE - Potential Dilutive Securities (Details) - shares	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Dilutive securities (in shares)	20,935,925	27,251,218
Series A Preferred Stock (as converted to shares of common stock)
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Dilutive securities (in shares)	14,171,775	23,656,049
Series B Preferred Stock (as converted to shares of common stock)
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Dilutive securities (in shares)	1,541,810	0
Options to purchase common stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Dilutive securities (in shares)	4,801,711	3,153,624
Warrants to purchase common stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Dilutive securities (in shares)	420,629	441,545

SUBSEQUENT EVENTS (Details)

SUBSEQUENT EVENTS (Details)	Apr. 13, 2022USD ($)ft²	Apr. 01, 2022USD ($)tranche	Mar. 31, 2022
Subsequent Event [Line Items]
Lessee, operating lease, renewal term			3 years
Subsequent Event
Subsequent Event [Line Items]
Area of office space expanded | ft²	2,432
Area of office space terminated | ft²	1,087
Area of office space extension | ft²	3,284
Lessee, operating lease, term of contract	4 years
Lessee, operating lease, renewal term	3 years
Operating lease, annual base rent	$ 400,000
Subsequent Event | Hercules Capital, Inc | Secured Debt
Subsequent Event [Line Items]
Principal amount		$ 75,000,000
Debt instrument, face amount, first tranche		25,000,000
Debt instrument, face amount, second tranche		10,000,000
Debt instrument, face amount, third tranche		15,000,000
Debt instrument, face amount, fourth tranche		25,000,000
Proceeds from term loan		$ 5,000,000
Interest rate		7.45%
Maximum interest rate		8.95%
Debt Instrument, Number Of Tranches | tranche		4
Subsequent Event | Hercules Capital, Inc | Secured Debt | Prime Rate
Subsequent Event [Line Items]
Basis spread		4.20%