Cidara Therapeutics (CDTX) 10-K 7 Mar 22 2021 FY Annual report Financial data

Cover Page

Cover Page - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Feb. 28, 2022	Jun. 30, 2021
Cover [Abstract]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2021
Current Fiscal Year End Date	--12-31
Document Transition Report	false
Entity File Number	001-36912
Entity Registrant Name	CIDARA THERAPEUTICS, INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	46-1537286
Entity Address, Address Line One	6310 Nancy Ridge Drive,
Entity Address, Address Line Two	Suite 101
Entity Address, City or Town	San Diego,
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	92121
City Area Code	(858)
Local Phone Number	752-6170
Title of 12(b) Security	Common Stock, $0.0001 Par Value
Trading Symbol	"CDTX"
Security Exchange Name	NASDAQ
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
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
ICFR Auditor Attestation Flag	false
Entity Shell Company	false
Entity Public Float			$ 98
Entity Common Stock, Shares Outstanding		68,154,642
Documents Incorporated by Reference	DOCUMENTS INCORPORATED BY REFERENCE Portions of the Registrant’s definitive Proxy Statement to be filed with the Securities and Exchange Commission pursuant to Schedule 14A in connection with the registrant’s 2022 Annual Meeting of Stockholders, which will be filed subsequent to the date hereof, are incorporated by reference into Part III of this Form 10-K. Such definitive proxy statement will be filed with the Securities and Exchange Commission not later than 120 days following the end of the Registrant’s fiscal year ended December 31, 2021.
Amendment Flag	false
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	FY
Entity Central Index Key	0001610618

Audit Information

Audit Information	12 Months Ended
	Dec. 31, 2021
Audit Information [Abstract]
Auditor Name	Ernst & Young LLP
Auditor Location	San Diego, California
Auditor Firm ID	42

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 59,680	$ 35,912
Restricted cash	2,593	7,037
Accounts receivable	5,356	11,175
Prepaid expenses and other current assets	4,069	3,067
Total current assets	71,698	57,191
Property and equipment, net	256	342
Operating lease right-of-use asset	2,287	868
Other assets	1,084	2,023
Total assets	75,325	60,424
Current liabilities:
Accounts payable	1,301	4,568
Accrued liabilities	10,198	7,959
Accrued compensation and benefits	4,859	4,210
Current deferred revenue	13,920	13,865
Current portion of term loan	2,591	7,023
Current portion of lease liability	1,148	939
Total current liabilities	34,017	38,564
Lease liability	1,322	0
Long-term deferred revenue	18,413	11,145
Total liabilities	53,752	49,709
Commitments and contingencies
Stockholders' equity:
Preferred stock, value, issued
Common stock, $0.0001 par value; 200,000,000 shares authorized at December 31, 2021 and 2020; 67,863,674 shares issued and outstanding at December 31, 2021; 44,876,408 shares issued and outstanding at December 31, 2020	7	4
Additional paid-in capital	398,733	345,411
Accumulated deficit	(377,167)	(334,700)
Total stockholders' equity	21,573	10,715
Total liabilities and stockholders' equity	75,325	60,424
Series X Convertible Preferred Stock
Stockholders' equity:
Preferred stock, value, issued	$ 0	$ 0

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2021	Dec. 31, 2020
Preferred stock, par value (USD per share)	$ 0.0001	$ 0.0001
Preferred stock, shares authorized (in shares)	10,000,000	10,000,000
Common stock, par value (USD per share)	$ 0.0001	$ 0.0001
Common stock, shares authorized (in shares)	200,000,000	200,000,000
Common stock, shares issued (in shares)	67,863,674	44,876,408
Common stock, shares outstanding (in shares)	67,863,674	44,876,408
Series X Convertible Preferred Stock
Preferred stock, par value (USD per share)	$ 0.0001	$ 0.0001
Preferred stock, shares authorized (in shares)	4,947,759	4,947,759
Preferred stock, shares issued (in shares)	1,870,713	1,096,519
Preferred stock, shares outstanding (in shares)	1,818,472	1,044,278

Consolidated Statements of Oper

Consolidated Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Revenues:
Total revenues	$ 49,572	$ 12,067	$ 20,915
Operating expenses:
Research and development	73,087	68,017	46,401
General and administrative	18,740	15,899	16,238
Total operating expenses	91,827	83,916	62,639
Loss from operations	(42,255)	(71,849)	(41,724)
Other income (expense):
Change in fair value of contingent forward purchase obligation	0	0	411
Interest income (expense), net	(212)	(262)	221
Total other income (expense)	(212)	(262)	632
Net loss	(42,467)	(72,111)	(41,092)
Comprehensive loss	(42,467)	(72,111)	(41,092)
Recognition of beneficial conversion feature	0	(2,762)	0
Net loss attributable to common shareholders	$ (42,467)	$ (74,873)	$ (41,092)
Basic earnings (loss) per share (USD per share)	$ (0.81)	$ (1.80)	$ (1.37)
Diluted earnings (loss) per share (USD per share)	$ (0.81)	$ (1.80)	$ (1.37)
Shares used to compute basic earnings (loss) per share (in shares)	52,453,452	41,557,350	29,934,809
Shares used to compute diluted earnings (loss) per share (in shares)	52,453,452	41,557,350	29,934,809

Consolidated Statements of Conv

Consolidated Statements of Convertible Preferred Stock and Stockholders' Equity (Deficit) - USD ($) $ in Thousands	Total	Stock Purchase Agreement	Rights Offering, January 2020	Controlled Equity Sales Agreement, Cantor Fitzgerald and Company	Underwritten Public Offering	Preferred StockSeries X Convertible Preferred Stock	Preferred StockSeries X Convertible Preferred StockUnderwritten Public Offering	Common Stock	Common StockStock Purchase Agreement	Common StockRights Offering, January 2020	Common StockControlled Equity Sales Agreement, Cantor Fitzgerald and Company	Common StockUnderwritten Public Offering	Additional Paid-In Capital	Additional Paid-In CapitalStock Purchase Agreement	Additional Paid-In CapitalRights Offering, January 2020	Additional Paid-In CapitalControlled Equity Sales Agreement, Cantor Fitzgerald and Company	Additional Paid-In CapitalUnderwritten Public Offering	Accumulated Deficit	Other Comprehensive Loss
Balance, beginning (in shares) at Dec. 31, 2018						445,231		27,816,014
Balance, beginning at Dec. 31, 2018	$ 59,139					$ 0		$ 3					$ 277,871					$ (218,735)	$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of stock (in shares)								2,095,887	4,781,408
Issuance of stock	5,289	$ 9,008											5,289	$ 9,008
Issuance of Series X Convertible Preferred Stock in exchange for common stock (in shares)						(120,000)		(1,200,000)
Issuance of common stock for exercise of stock options (in shares)								2,952
Issuance of common stock for exercise of stock options	7												7
Issuance of common stock for restricted share units vested (in shares)								99,704
Issuance of common stock under Employee Stock Purchase Plan (in shares)								242,501
Issuance of common stock under Employee Stock Purchase Plan	411												411
Stock-based compensation	5,073												5,073
Net loss	(41,092)																	(41,092)
Balance, ending (in shares) at Dec. 31, 2019						565,231		33,838,466
Balance, ending at Dec. 31, 2019	37,835					$ 0		$ 3					297,659					(259,827)	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of stock (in shares)						531,288				6,639,307	3,515,871
Issuance of stock			$ 29,186	$ 11,208						$ 1					$ 29,185	$ 11,208
Recognition of beneficial conversion feature													2,762					(2,762)
Issuance of Series X Convertible Preferred Stock in exchange for common stock (in shares)						(52,241)		(522,410)
Issuance of common stock for exercise of stock options (in shares)								5,411
Issuance of common stock for exercise of stock options	$ 14												14
Issuance of common stock for restricted share units vested (in shares)	74,804
Issuance of common stock under Employee Stock Purchase Plan (in shares)								280,139
Issuance of common stock under Employee Stock Purchase Plan	$ 493												493
Stock-based compensation	4,090												4,090
Net loss	(72,111)																	(72,111)
Balance, ending (in shares) at Dec. 31, 2020						1,044,278		44,876,408
Balance, ending at Dec. 31, 2020	10,715					$ 0		$ 4					345,411					(334,700)	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of stock (in shares)							774,194	5,523,429				17,064,511
Issuance of stock	$ 12,316				$ 36,552			$ 1				$ 2	12,315				$ 36,550
Issuance of common stock for exercise of stock options (in shares)	2,930							2,930
Issuance of common stock for exercise of stock options	$ 6												6
Issuance of common stock for restricted share units vested (in shares)	106,725
Issuance of common stock under Employee Stock Purchase Plan (in shares)								289,671
Issuance of common stock under Employee Stock Purchase Plan	$ 437												437
Stock-based compensation	4,014												4,014
Net loss	(42,467)																	(42,467)
Balance, ending (in shares) at Dec. 31, 2021						1,818,472		67,863,674
Balance, ending at Dec. 31, 2021	$ 21,573					$ 0		$ 7					$ 398,733					$ (377,167)	$ 0

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Operating activities:
Net loss	$ (42,467)	$ (72,111)	$ (41,092)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	189	286	328
Stock-based compensation	4,014	4,090	5,073
Non-cash interest expense	12	16	28
Amortization of debt issuance costs	3	5	8
Amortization of operating lease right-of-use assets	(1,419)	764	(1,713)
Change in fair value of contingent forward purchase obligations	0	0	(411)
Changes in operating assets and liabilities:
Accounts receivable	5,819	(11,165)	(10)
Prepaid expenses and other current assets	(229)	1,682	(2,936)
Accounts payable and accrued liabilities	(1,093)	6,591	(784)
Accrued compensation and benefits	1,085	1,045	1,244
Deferred revenue	7,323	15,207	9,803
Operating lease liabilities	1,531	(821)	1,760
Other assets	0	0	170
Net cash used in operating activities	(25,232)	(54,411)	(28,532)
Investing activities:
Purchases of property and equipment	(41)	(186)	(35)
Net cash used in investing activities	(41)	(186)	(35)
Financing activities:
Proceeds from underwritten public offering, net of issuance costs	36,552	0	0
Proceeds from issuance of common stock	12,483	11,041	5,289
Proceeds from exercise of stock options	6	14	7
Deferred public offering costs	0	0	(31)
Principal repayments of Term Loan	(4,444)	(2,963)	0
Net cash provided by financing activities	44,597	37,278	14,273
Net (decrease) increase in cash, cash equivalents, and restricted cash	19,324	(17,319)	(14,294)
Cash, cash equivalents, and restricted cash at beginning of year	42,949	60,268	74,562
Cash, cash equivalents, and restricted cash at end of year	62,273	42,949	60,268
Supplemental disclosure of cash flows:
Interest paid	228	445	616
Non-cash investing activity:
Right-of-use asset obtained in exchange for lease liability	2,341	0	0
Purchases of property and equipment included in accounts payable and accrued liabilities	78	12	10
Non-cash financing activities:
Purchase of shares pursuant to Employee Stock Purchase Plan	437	493	411
Proceeds from public offering of common stock, net of issuance costs, included in prepaid expenses and other current assets	0	167	0
Series X Convertible Preferred Stock
Financing activities:
Proceeds from issuance of common stock	0	29,186	0
Stock Purchase Agreement
Financing activities:
Proceeds from issuance of common stock	$ 0	$ 0	$ 9,008

THE COMPANY AND BASIS OF PRESEN

THE COMPANY AND BASIS OF PRESENTATION	12 Months Ended
	Dec. 31, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
THE COMPANY AND BASIS OF PRESENTATION	THE COMPANY AND BASIS OF PRESENTATION Description of Business Cidara Therapeutics, Inc., or the Company, was originally incorporated in Delaware in December 2012 as K2 Therapeutics, Inc., and its name was changed to Cidara Therapeutics, Inc. in July 2014. The Company is a biotechnology company focused on the discovery, development and commercialization of long-acting therapeutics designed to transform the standard of care for patients facing serious diseases. The Company is focused on infectious diseases and oncology. The Company’s lead product candidate is rezafungin acetate, an intravenous formulation of a novel echinocandin antifungal. Rezafungin is being developed as a once-weekly, high-exposure therapy for the first-line treatment and prevention of serious, invasive fungal infections. In addition, the Company is using its Cloudbreak® platform to develop a potential new class of drugs called DFCs for the prevention and treatment of serious diseases. The Company's initial development programs target influenza and other viral infections, including respiratory syncytial virus, human immunodeficiency virus and the SARS-CoV-2 strains causing COVID-19. In addition, the Company has expanded the Cloudbreak platform to discover and develop DFC's to treat cancer. The Company formed wholly-owned subsidiaries, Cidara Therapeutics UK Limited, in England, and Cidara Therapeutics (Ireland) Limited, in Ireland, in March 2016 and October 2018, respectively, for the purpose of developing its product candidates in Europe. Basis of Presentation The Company has a limited operating history and the sales and income potential of the Company’s business and market are unproven. The Company has experienced net losses and negative cash flows from operating activities since its inception. At December 31, 2021, the Company had an accumulated deficit of $377.2 million. The Company expects to continue to incur net losses into the foreseeable future. Successful transition to attaining profitable operations is dependent upon achieving a level of revenues adequate to support the Company’s cost structure. At December 31, 2021, the Company had cash, cash equivalents and restricted cash of $62.3 million. Based on the Company’s current business plan, management believes that existing cash and cash equivalents will not be sufficient to fund the Company’s obligations for twelve months from the issuance of these financial statements. The Company’s ability to execute its operating plan depends on its ability to obtain additional funding through equity offerings, debt financings or potential licensing and collaboration arrangements. The accompanying consolidated financial statements have been prepared assuming the Company will continue as a going concern, which contemplates the realization of assets and settlement of liabilities in the normal course of business. However, the Company’s current working capital, anticipated operating expenses and net losses and the uncertainties surrounding its ability to raise additional capital as needed, as discussed below, raise substantial doubt about its ability to continue as a going concern for a period of one year following the date that these financial statements are issued. The consolidated financial statements do not include any adjustments for the recovery and classification of assets or the amounts and classification of liabilities that might be necessary should the Company be unable to continue as a going concern. The Company plans to continue to fund its losses from operations through cash and cash equivalents on hand, as well as through future equity offerings, debt financings, other third party funding, and potential licensing or collaboration arrangements. There can be no assurance that additional funds will be available when needed from any source or, if available, will be available on terms that are acceptable to the Company. Even if the Company raises additional capital, it may also be required to modify, delay or abandon some of its plans which could have a material adverse effect on the Company’s business, operating results and financial condition and the Company’s ability to achieve its intended business objectives. Any of these actions could materially harm the Company’s business, results of operations and future prospects. In addition to the foregoing, the Company is monitoring closely the impact of the COVID-19 pandemic on its business and has taken steps designed to protect the health and safety of its employees while continuing its operations. Given the level of uncertainty regarding the duration and impact of the COVID-19 pandemic on capital markets and the U.S. economy, the Company is currently unable to assess the impact of the COVID-19 pandemic on its future access to capital. The Company is continuing to monitor the spread of COVID-19 and its potential impact on the Company's operations. The full extent to which the COVID-19 pandemic will impact the Company's business, results of operations, financial condition, clinical trials, and preclinical research will depend on future developments that are highly uncertain, including actions taken to contain or treat COVID-19 and their effectiveness, as well as the economic impact on national and international markets. Basis of Consolidation The consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries. All significant intercompany accounts and transactions have been eliminated in consolidation. Use of Estimates The preparation of financial statements in conformity with U.S. generally accepted accounting principles, or GAAP, requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities at the date of the financial statements, and the reported amounts of expenses during the reporting period. The Company evaluates its estimates and assumptions on an ongoing basis. The most significant estimates in the Company’s consolidated financial statements relate to estimating the fair value of the Company’s stock options, estimated collaboration expenses and incurred expenses related to the Mundipharma Collaboration Agreement and Janssen Collaboration Agreement (as defined below), certain accruals, including those related to nonclinical and clinical activities, and the Standalone Selling Price of performance obligations associated with license agreements. Although the estimates are based on the Company’s knowledge of current events, comparable companies, and actions it may undertake in the future, actual results may ultimately materially differ from these estimates and assumptions. Segment Information Operating segments are identified as components of an enterprise about which separate discrete financial information is available for evaluation by the chief operating decision maker, the Chief Executive Officer, in making decisions regarding resource allocation and assessing performance. The Company views its operations and manages its business as one operating segment.

SUMMARY OF SIGNIFICANT ACCOUNTI

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	12 Months Ended
	Dec. 31, 2021
Accounting Policies [Abstract]
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Cash, Cash Equivalents, and Restricted Cash The Company considers all short-term investments purchased with a maturity of three months or less when acquired to be cash equivalents. Restricted cash represents cash that the Company is required to maintain on hand in order to maintain compliance with an operating covenant in the Third Amendment to the Company's Loan Agreement with Pacific Western Bank. See Note 5 for additional information. Accounts Receivable Accounts receivable are recorded at their net invoice value and are not interest bearing. The Company reserves specific receivables when collectability is no longer probable. These reserves are re-evaluated on a regular basis and are adjusted, as needed. Once a receivable is deemed to be uncollectable, such balance is recorded as an allowance for credit losses. No such allowance existed at December 31, 2021 or 2020. Property and Equipment The Company records property and equipment at cost, which consists of lab equipment, computer equipment and software, office equipment, furniture and fixtures and leasehold improvements. Property and equipment is depreciated using the straight-line method over the estimated useful lives (generally three Concentration of Credit Risk The Company’s financial instruments that are exposed to concentrations of credit risk consist primarily of cash and cash equivalents. The Company maintains deposits in government insured financial institutions in excess of government insured limits. The Company invests its cash balances in financial institutions that it believes have high credit quality, has not experienced any losses on such accounts and does not believe it is exposed to significant credit risk. Patent Costs The Company expenses all costs as incurred in connection with patent applications (including direct application fees, and the legal and consulting expenses related to making such applications) and such costs are included in general and administrative expenses in the accompanying statements of operations and comprehensive loss. Income Taxes The Company follows the Financial Accounting Standards Board, or FASB, Accounting Standards Codification , or ASC, 740, Income Taxes , or ASC 740, in reporting deferred income taxes. ASC 740 requires a company to recognize deferred tax assets and liabilities for expected future income tax consequences of events that have been recognized in the Company’s consolidated financial statements. Under this method, deferred tax assets and liabilities are determined based on temporary differences between financial statement carrying amounts and the tax basis of assets and liabilities using enacted tax rates in the years in which the temporary differences are expected to reverse. Valuation allowances are provided if, based on the weight of available evidence, it is more likely than not that some or all of the deferred tax assets will not be realized. The Company accounts for uncertain tax positions pursuant to ASC 740, which prescribes a recognition threshold and measurement process for financial statement recognition of uncertain tax positions taken or expected to be taken in a tax return. If the tax position meets this threshold, the benefit to be recognized is measured as the tax benefit having the highest likelihood of being realized upon ultimate settlement with the taxing authority. The Company recognizes interest accrued related to unrecognized tax benefits and penalties in the provision for income taxes. Revenue Recognition The Company recognizes revenue is accordance with ASC Topic 606, Revenue from Contracts with Customers , or Topic 606, which applies to all contracts with customers, except for contracts that are within the scope of other standards, such as leases, insurance, collaboration arrangements and financial instruments. Under Topic 606, an entity recognizes revenue when its customer obtains control of promised goods or services, in an amount that reflects the consideration that the entity expects to receive in exchange for those goods or services. To determine revenue recognition for arrangements that an entity determines are within the scope of Topic 606, the entity performs the following five steps: (i) identify the contract(s) with a customer; (ii) identify the performance obligations in the contract; (iii) determine the transaction price; (iv) allocate the transaction price to the performance obligations in the contract; and (v) recognize revenue when (or as) the entity satisfies a performance obligation. The Company only applies the five-step model to contracts when it is probable that the entity will collect the consideration it is entitled to in exchange for the goods or services it transfers to the customer. At contract inception, once the contract is determined to be within the scope of Topic 606, the Company assesses the goods or services promised within each contract and determines those that are performance obligations, and assesses whether each promised good or service is distinct. The Company then recognizes as revenue the amount of the transaction price that is allocated to the respective performance obligation when (or as) the performance obligation is satisfied. In a contract with multiple performance obligations, the Company must develop estimates and assumptions that require judgment to determine the underlying stand-alone selling price for each performance obligation, which determines how the transaction price is allocated among the performance obligations. The estimation of the stand-alone selling price(s) may include estimates regarding forecasted revenues or costs, development timelines, discount rates, and probabilities of technical and regulatory success. The Company evaluates each performance obligation to determine if it can be satisfied at a point in time or over time. Any change made to estimated progress towards completion of a performance obligation and, therefore, revenue recognized will be recorded as a change in estimate. In addition, variable consideration must be evaluated to determine if it is constrained and, therefore, excluded from the transaction price. If a license to the Company’s intellectual property is determined to be distinct from the other performance obligations identified in a contract, the Company recognizes revenues from the transaction price allocated to the license when the license is transferred to the licensee and the licensee is able to use and benefit from the license. For licenses that are bundled with other promises, the Company utilizes 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 for purposes of recognizing revenue from the allocated transaction price. The Company evaluates the measure of progress at each reporting period and, if necessary, adjusts the measure of performance and related revenue or expense recognition as a change in estimate. At the inception of each arrangement that includes milestone payments, the Company evaluates whether the milestones are considered probable of being reached. If it is probable that a significant revenue reversal would not occur, the associated milestone value is included in the transaction price. Milestone payments that are not within the Company’s or a collaboration partner’s control, such as regulatory approvals, are generally 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 milestones that are within its or a collaboration partner’s control, such as operational developmental 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 will affect collaboration revenues and earnings in the period of adjustment. Revisions to the Company’s estimate of the transaction price may also result in negative collaboration revenues and earnings in the period of adjustment. For arrangements that include sales-based royalties, including commercial milestone payments based on the level of sales, and a license is deemed to be the predominant item to which the royalties relate, the Company will recognize 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 from collaborative arrangements. In September 2019, the Company entered into a Collaboration and License Agreement, or the Mundipharma Collaboration Agreement, with Mundipharma Medical Company, or Mundipharma. The Company concluded that there were three significant performance obligations under the Mundipharma Collaboration Agreement: the license, the research and development services, and the clinical supply services, and that the obligations are distinct from each other. Revenue associated with the license was recognized upon delivery in September 2019. In March 2021, the Company entered into an exclusive worldwide license and collaboration agreement, or the Janssen Collaboration Agreement, with Janssen. The Company concluded that there were three significant performance obligations under the Janssen Collaboration Agreement: the license, the research and development services, and the clinical supply services, and that the obligations are distinct from each other. Revenue associated with the license was recognized upon delivery in May 2021. The Company concluded that progress towards completion of the research and development and clinical supply performance obligations related to the Mundipharma Collaboration Agreement is best measured in an amount proportional to the collaboration expenses incurred and the total estimated collaboration expenses. The Company periodically reviews and updates the estimated collaboration expenses, when appropriate, which may adjust revenue recognized for the period. While such changes to the Company’s estimates have no impact on the Company’s reported cash flows, the amount of revenue recorded in the period could be materially impacted. Revenue from research and development services for the Janssen Collaboration Agreement is recognized based on actual amounts billed as the underlying services are provided and billed at market rates. The transaction prices to be recognized as revenue under both the Mundipharma Collaboration Agreement and the Janssen Collaboration Agreement consist of upfront payments and estimated reimbursable research and development and clinical supply costs. Potential future payments for variable consideration, such as clinical, regulatory or commercial milestones, will be recognized when it is probable that, if recorded, a significant reversal will not take place. Potential future royalty payments will be recorded as revenue when the associated sales occur. See Note 8 for additional information. Research and Development Costs Research and development expenses consist of wages, benefits and stock-based compensation charges for research and development employees, scientific consultant fees, facilities and overhead expenses, laboratory supplies, manufacturing expenses, and nonclinical and clinical trial costs. The Company accrues nonclinical and clinical trial expenses based on work performed, which relies on estimates of total costs incurred based on patient enrollment, completion of studies, and other events. Costs incurred in purchasing technology assets and intellectual property are charged to research and development expense if the technology has not been conclusively proven to be feasible and has no alternative future use. Preclinical and Clinical Trial Accruals The Company makes estimates of its accrued expenses as of each balance sheet date in the financial statements based on the facts and circumstances known at that time. Accrued expenses for preclinical studies and clinical trials are based on estimates of costs incurred and fees that may be associated with services provided by contract research organizations, or CROs, clinical trial investigational sites and other clinical trial-related activities. Payments under certain contracts with such parties depend on factors such as successful enrollment of patients, site initiation and the completion of clinical trial milestones. In accruing for these services, the Company estimates the time period over which services will be performed and the level of effort to be expended in each period. If possible, the Company obtains information regarding unbilled services directly from these service providers. However, the Company may be required to estimate these services based on other available information. If the Company underestimates or overestimates the activities or fees associated with a study or service at a given point in time, adjustments to research and development expenses may be necessary in future periods. Historically, estimated accrued liabilities have approximated actual expense incurred. Subsequent changes in estimates may result in a material change in accruals. Stock-Based Compensation The Company accounts for stock-based compensation expense related to stock options, restricted stock units, or RSUs, performance-based RSUs, or PRSUs, and ESPP (as defined below) rights by estimating the fair value on the date of grant. The Company estimates the fair value of stock options granted to employees and non-employees using the Black-Scholes option pricing model. The fair value of RSUs and PRSUs granted to employees is estimated based on the closing price of the Company's common stock on the date of grant. The assumptions included in the Black-Scholes option pricing model includes (a) the risk-free interest rate, (b) the expected volatility of the Company's stock, (c) the expected term of the award, and (d) the expected dividend yield. For periods ending on or before December 31, 2020, the Company based its estimate of expected volatility on the historical volatility of a group of similar companies that are publically traded, due to the lack of an adequate history of a public market for the trading of the Company's common stock and a lack of adequate company-specific historical and implied volatility data. For these analyses, the Company selected companies with comparable characteristics, including enterprise value, risk profiles, and position within the industry, and with historical share price information sufficient to meet the expected life of the stock-based awards. The Company computed the expected volatility data using the daily close prices for the selected companies' shares during the equivalent period of the calculated expected term of the Company's stock-based awards. In January 2021 the Company began to compute the expected volatility data using the daily close prices for the Company's common stock during the equivalent period of the calculated expected term of the Company's stock-based awards. The Company estimated the expected life of employee stock options using the “simplified” method, whereby the expected life equals the average of the vesting term and the original contractual term of the option. The risk-free interest rates for periods within the expected life of the option are based on the yields of zero-coupon U.S. treasury securities. The expected dividend yield of zero reflects that the Company has not paid cash dividends since inception and do not intend to pay cash dividends in the foreseeable future. For awards subject to time-based vesting conditions, including those with a graded vesting schedule, stock-based compensation expense is recognized using the straight-line method. For performance-based awards to employees, (i) the fair value of the award is determined on the grant date, (ii) the Company assesses the probability of the individual performance milestones under the award being achieved and (iii) the fair value of the shares subject to the milestone is expensed over the implicit service period commencing once management believes the performance criteria is probable of being met. The Company recognizes forfeitures related to stock-based compensation as they occur and any compensation cost previously recognized for awards for which the requisite service has not been completed is reversed in the period that the award is forfeited. Net Loss Per Share Basic net loss per share is calculated by dividing the net loss allocable to common shares by the weighted-average number of common shares outstanding for the period, without consideration for potentially dilutive securities. Diluted net loss per share is computed by dividing the net loss allocable to common shares by the weighted-average number of common shares and dilutive stock equivalents outstanding for the period determined using the treasury-stock and if-converted methods. Dilutive common stock equivalents are comprised of warrants, Series X Convertible Preferred Stock, RSUs, PRSUs and options outstanding under the Company’s stock option plans. For all periods presented, there is no difference in the number of shares used to calculate basic and diluted shares outstanding due to the Company's net loss position. Net loss allocable to common shares for the year ended December 31, 2020 includes non-cash deemed dividends of $2.8 million resulting from the recognition of a beneficial conversion feature. See Note 6 for additional information. The following table sets forth the outstanding potentially dilutive securities that have been excluded in the calculation of diluted net loss per share because doing so would be anti-dilutive (in common stock equivalent shares): December 31, 2021 2020 2019 Common stock warrants 12,517,328 12,517,328 12,517,328 Series X Convertible Preferred stock 18,184,720 10,442,780 5,652,310 Common stock options, RSUs and PRSUs issued and outstanding 9,470,178 6,787,033 5,360,563 Total 40,172,226 29,747,141 23,530,201 Fair Value of Financial Instruments The Company follows ASC 820-10 issued by the FASB with respect to fair value reporting for financial assets and liabilities. The guidance defines fair value, provides guidance for measuring fair value and requires certain disclosures. The guidance does not apply to measurements related to share-based payments. The guidance discusses valuation techniques such as the market approach (comparable market prices), the income approach (present value of future income or cash flow), and the cost approach (cost to replace the service capacity of an asset or replacement cost). The guidance establishes a fair value hierarchy that prioritizes the inputs to valuation techniques used to measure fair value into three broad levels. The Company’s financial instruments consist of cash and cash equivalents, restricted cash, accounts receivable, accounts payable, accrued liabilities, lease liability, and a term loan. Fair value estimates of these instruments are made at each reporting period end based on relevant market information. These estimates may be subjective in nature and involve uncertainties and matters of significant judgment and therefore cannot be determined with precision. The carrying amount of cash and cash equivalents, restricted cash, accounts receivable, accounts payable, and accrued liabilities are generally considered to be representative of their respective fair values because of the short-term nature of those instruments. The Company believes that the fair value of the term loan approximates its carrying value. Recently Issued Accounting Standards Recently Issued Accounting Standards Not Yet Adopted In August 2020, the FASB issued ASU 2020-06, "Accounting for Convertible Instruments and Contracts in an Entity's Own Equity," simplifies the accounting for certain convertible instruments by removing the separation models for convertible debt with a cash conversion feature or convertible instruments with a beneficial conversion feature. As a result, more convertible debt instruments will be reported as a single liability instrument with no separate accounting for embedded conversion features. Additionally, this ASU amends the diluted EPS calculation for convertible instruments by requiring the use of the if-converted method. The treasury stock method is no longer available. Entities may adopt this ASU using either a full or modified retrospective approach, and it is effective for interim and annual reporting periods beginning after December 15, 2021. Early adoption is permitted for interim and annual reporting periods beginning after December 15, 2020. The Company adopted ASU 2020-06 effective January 1, 2022. The adoption of this standard did not have a material impact on the Company's consolidated financial statements. Recently Adopted Accounting Standards In December 2019, the FASB issued ASU 2019-12, "Simplifying the Accounting for Income Taxes," which eliminates certain exceptions within ASC 740, Income Taxes, and clarifies other aspects of the current guidance to promote consistency among reporting entities. The Company adopted ASU 2019-12 effective January 1, 2021. The adoption of this standard did not have a material impact on the Company's consolidated financial statements.

FAIR VALUE MEASUREMENTS

FAIR VALUE MEASUREMENTS	12 Months Ended
	Dec. 31, 2021
Fair Value Disclosures [Abstract]
FAIR VALUE MEASUREMENTS	FAIR VALUE MEASUREMENTS The Company follows ASC 820-10, Fair Value Measurements and Disclosures , which among other things, defines fair value, establishes a consistent framework for measuring fair value and expands disclosure for each major asset and liability category measured at fair value on either a recurring or nonrecurring basis. Fair value is an exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. As such, fair value is a market-based measurement determined based on assumptions that market participants would use in pricing an asset or liability. The carrying amounts of accounts payable and accrued liabilities are considered to be representative of their respective fair values because of the short-term nature of those instruments. Based on the borrowing rates available to the Company for loans with similar terms, which is considered a Level 2 input as described below, the Company believes that the fair value of the term loan approximates its carrying value. As a basis for considering such assumptions, a three-tier fair value hierarchy has been established, which prioritizes the inputs used in measuring fair value as follows: Level 1: Observable inputs such as quoted prices (unadjusted) in active markets for identical assets or liabilities; Level 2: Inputs, other than the quoted prices in active markets, that are observable either directly or indirectly; and Level 3: Unobservable inputs for which there is little or no market data, which require the reporting entity to develop its own assumptions, which reflect those that a market participant would use. The Company classifies investments in money market funds within Level 1 as the prices are available from quoted prices in active markets. None of the Company’s non-financial assets or liabilities are recorded at fair value on a non-recurring basis. No transfers between levels have occurred during the periods presented. The following tables summarize the Company’s financial instruments measured at fair value on a recurring basis (in thousands): TOTAL LEVEL 1 LEVEL 2 LEVEL 3 December 31, 2021 Assets: Cash and money market accounts $ 59,680 $ 59,680 $ — $ — Restricted cash and money market accounts 2,593 2,593 — — Total assets at fair value $ 62,273 $ 62,273 $ — $ — December 31, 2020 Assets: Cash and money market accounts $ 35,912 $ 35,912 $ — $ — Restricted cash and money market accounts 7,037 7,037 — — Total assets at fair value $ 42,949 $ 42,949 $ — $ —

PROPERTY AND EQUIPMENT

PROPERTY AND EQUIPMENT	12 Months Ended
	Dec. 31, 2021
Property, Plant and Equipment [Abstract]
PROPERTY AND EQUIPMENT	PROPERTY AND EQUIPMENT Property and equipment consists of the following (in thousands): December 31, 2021 2020 Laboratory equipment $ 2,369 $ 2,304 Leasehold improvements 425 425 Computer hardware and software 425 404 Office equipment 119 119 Furniture and fixtures 142 142 3,480 3,394 Less accumulated depreciation and amortization (3,224) (3,052) Total $ 256 $ 342 Depreciation and amortization of property and equipment of $0.2 million, $0.3 million and $0.3 million were recorded for the years ended December 31, 2021, 2020 and 2019, respectively.

DEBT

DEBT	12 Months Ended
	Dec. 31, 2021
Debt Disclosure [Abstract]
DEBT	DEBT Term Loan On October 3, 2016, the Company entered into a loan and security agreement, or the Loan Agreement, with Pacific Western Bank, as the collateral agent and a lender, or the Lender, pursuant to which the Lender agreed to lend to the Company up to $20.0 million in a series of term loans, or the Term Loan. Contemporaneously, the Company borrowed $10.0 million from the Lender, or the Term A Loan. Under the terms of the Loan Agreement, because the Company achieved positive clinical results from the STRIVE Phase 2 clinical trial of rezafungin by March 31, 2018, or the Milestone, the Company had the option to borrow, at its sole discretion, until October 3, 2018, from the Lender up to an additional $10.0 million, or Term B Loan. The Company did not borrow any funds available under the Term B Loan before the draw period ended. The Company’s obligations under the Loan Agreement are secured by a first priority security interest in substantially all of the Company’s current and future assets, other than its intellectual property, which is subject to a double negative pledge. The Company may prepay the borrowed amounts, provided that the Company will be obligated to pay a prepayment fee equal to (i) 2.0% of the applicable principal amount of the Term Loan if the prepayment occurs before the first anniversary of the applicable funding date, and (ii) 1.0% of the applicable principal amount of the Term Loan if the prepayment occurs after the first anniversary of the funding date of such Term Loan but on or prior to the second anniversary of the funding date of such Term Loan. While any amounts are outstanding under the Loan Agreement, the Company is subject to a number of affirmative and restrictive covenants, including covenants regarding dispositions of property, business combinations or acquisitions, incurring additional indebtedness and transactions with affiliates, among other customary covenants. The Company is also restricted from paying dividends or making other distributions or payments on its capital stock, subject to limited exceptions. Pursuant to the Loan Agreement, on October 3, 2016, the Company issued to the Lender a warrant to purchase an aggregate of up to 17,331 shares of the Company’s common stock at an exercise price of $11.54 per share. If the Company borrows additional amounts under the Loan Agreement, it will, in connection with any such borrowing, issue the Lender an additional warrant to purchase that number of shares of the Company’s common stock as is equal to 2.0% of the additional principal amount borrowed divided by the exercise price. The exercise price shall be equal to the 30-day average closing price of the Company’s common stock, calculated as of the date immediately prior to the date of such additional borrowing. The warrants are immediately exercisable and will expire ten years from the date of the grant. On June 13, 2018, the Company and the Lender entered into a First Amendment to the Loan Agreement, which reset the Milestone to require the Company to achieve positive data from Part B of the STRIVE Phase 2 clinical trial of rezafungin on or prior to July 31, 2019. On July 27, 2018, the Company and the Lender entered into a Second Amendment to the Loan Agreement, which amended, among other things, the interest-only period, the date of maturity, or Maturity Date, and the interest rate. The interest-only period will be followed by equal monthly payments of principal and interest. The Term Loans will bear interest at a variable annual rate equal to the greater of (i) 4.5% or (ii) the Lender’s prime interest rate plus 0.75%. At December 31, 2021, the Term A Loans bears interest at 4.50%. On July 29, 2019, the Company announced positive data from Part B of the STRIVE clinical trial, which satisfied the Milestone. Within 30 days of satisfying the Milestone, the Company was required to agree with the Lender on an amendment to the Loan Agreement to define a new financial covenant and/or milestone for fiscal year 2019 and all subsequent fiscal years during the term of the Loan Agreement. On August 27, 2019, the Lender extended the deadline to execute this amendment to October 15, 2019, and on October 11, 2019, the Lender further extended this deadline until November 7, 2019. On November 5, 2019, the Company and the Lender entered into a Third Amendment to the Loan Agreement, which reset the operating covenant to require the Company to maintain cash equal to or greater than the Company's outstanding indebtedness to the Lender, which is equivalent to a compensating balance and results in a restricted cash balance of $2.6 million and $7.0 million as of December 31, 2021 and 2020, respectively. The amendment also extended the interest-only period through April 3, 2020 and the maturity date through July 3, 2022. On March 16, 2021, the Company and the Lender entered into a Fourth Amendment to the Loan Agreement, which modified certain debt covenants under the original agreement but had no impact on current or future cash flows. The Company evaluated the First, Second, Third and Fourth Amendments and determined that the amendments did not represent a substantial change from the original Loan Agreement. Accordingly, the Company accounted for the amendments as debt modifications. Costs previously deferred under the original terms of the Loan Agreement are amortized into interest expense over the new term of the Third Amendment. Upon the occurrence of certain events, including but not limited to the Company’s failure to satisfy its payment obligations under the Loan Agreement, the breach of certain of its other covenants under the Loan Agreement or the occurrence of a material adverse change, the Lender has the right, among other remedies, to declare all principal and interest and other amounts due to the Lender under the Loan Agreement immediately due and payable. The principal payments due under the Loan Agreement have been classified as a current liability at December 31, 2020 due to the considerations discussed in Note 1 and the assessment that the material adverse change clause under the Loan Agreement is not within the Company's control. The Company has not been notified of an event of default by the Lenders as of the date of the filing of this Form 10-K. As of December 31, 2021, future principal payments due under the Loan Agreement, as amended, are as follows (in thousands): Year ended: December 31, 2022 $ 2,593 Total future principal payments due under the Loan Agreement $ 2,593 The fair value of the warrants to purchase common stock issued in connection with Term Loan A was estimated on the date of issuance using the Black-Scholes valuation model and recorded to additional paid-in capital. The fair value of the

STOCKHOLDERS_ EQUITY

STOCKHOLDERS’ EQUITY	12 Months Ended
	Dec. 31, 2021
Equity [Abstract]
STOCKHOLDERS’ EQUITY	STOCKHOLDERS’ EQUITY Controlled Equity Sales Agreement In September 2019, the Company began to sell shares of common stock under a controlled equity sales agreement with Cantor Fitzgerald & Co, or the Sales Agreement. During the years ended December 31, 2021 and 2020, the Company sold 5,523,429 and 3,515,871 shares of common stock for net proceeds of approximately $12.3 million and $11.2 million, respectively, after deducting placement agent fees. As of December 31, 2021, the aggregate offering price remaining under the Sales Agreement is $48.5 million. 2020 Rights Offering On January 22, 2020, the Company initiated a rights offering to raise gross proceeds of $30.0 million through the distribution of subscription rights to holders of its common stock, Series X Preferred Stock, and warrants to purchase common stock issued on May 21, 2018, or the Rights Offering. On February 12, 2020, the Company sold 6,639,307 shares of common stock and 531,288 shares of Series X Preferred Stock for $2.51 and $25.10 per share, respectively, for aggregate gross proceeds of $30.0 million. Total offering costs of $0.8 million were offset against the proceeds from the sale of common stock for total net proceeds of $29.2 million. The Rights Offering was fully backstopped by Biotechnology Value Fund, L.P. and Stonepine Capital, LP. With respect to the Series X Convertible Preferred Stock, because the effective conversion price on the commitment date was below the fair value of the common stock at the date of issuance, a beneficial conversion feature with a calculated fair value of $2.8 million existed at the issuance date. As the Series X Convertible Preferred Stock is fully convertible at issuance, the full $2.8 million was recorded at issuance as a deemed dividend on February 12, 2020. This non-cash deemed dividend impacted accumulated deficit and additional paid in capital at December 31, 2020 and net loss attributable to common stockholders and net loss attributable to common stockholders per share for the year ended December 31, 2020. With respect to the common stock, because the purchase price was below fair value on the issuance date, a bonus element exists at the issuance date. Basic and diluted net loss per common share and shares used to compute basic and diluted net loss per common share have been retroactively adjusted for all periods presented to reflect this bonus element. 2021 Public Offering On October 13, 2021, the Company completed concurrent but separate public offerings of 17,064,511 shares of its common stock, including the exercise in full by the underwriters of their option to purchase an additional 2,225,805 shares of common stock, at a price to the public of $1.55 per share, and 774,194 shares of its Series X Convertible Preferred Stock at a price to the public of $15.50 per share, for aggregate gross proceeds of $38.5 million. The Company received total net proceeds of $36.6 million, after deducting underwriting discounts, commissions, and other expenses payable by the Company. Mundipharma Stock Purchase Agreement On September 3, 2019, the Company entered into a Stock Purchase Agreement, with Mundipharma AG, or the Purchaser, a related party, pursuant to which the Company issued to the Purchaser 4,781,408 shares of its common stock in a private placement at a price per share of $1.884 (a 20% premium to the volume weighted average price of the Company’s common stock for the 10 trading days prior to September 3, 2019) for an aggregate purchase price of approximately $9.0 million. Preferred Stock Under the amended and restated certificate of incorporation, the Company’s board of directors has the authority, without further action by the stockholders, to issue up to 10,000,000 shares of preferred stock in one or more series, to establish from time to time the number of shares to be included in each such series, to fix the rights, preferences and privileges of the shares of each wholly unissued series and any qualifications, limitations or restrictions thereon and to increase or decrease the number of shares of any such series, but not below the number of shares of such series then outstanding. The Company had 10,000,000 shares of preferred stock authorized at December 31, 2021. In May 2018, the Company designated 5,000,000 shares of preferred stock as Series X Convertible Preferred Stock with a par value of $0.0001 per share. On March 22, 2019, the Company entered into an Exchange Agreement with Biotechnology Value Fund, L.P., and certain of its affiliated entities (collectively, BVF), pursuant to which BVF, without monetary consideration, agreed to exchange an aggregate of 1,200,000 shares of the Company’s common stock for an aggregate of 120,000 shares of the Company’s Series X Convertible Preferred Stock. On August 12, 2020, at the request of certain holders, 52,241 shares of the Company’s Series X Convertible Preferred Stock were converted to an aggregate of 522,410 shares of the Company’s common stock. As of December 31, 2021 and 2020 shares of preferred stock designated as Series X Convertible Preferred Stock totaled 4,947,759. The specific terms of the Series X Convertible Preferred Stock are as follows: Conversion: Each share of Series X Convertible Preferred Stock is convertible at the option of the holder into 10 shares of common stock. Holders are not permitted to convert Series X Convertible Preferred Stock into common stock if, after conversion, the holder, its affiliates, and any other person whose beneficial ownership of common stock would be aggregated with the holder's for purposes of Section 13(d) or Section 16 of the Exchange Act, would beneficially own more than 9.99% of the number of shares of common stock outstanding immediately after the conversion. Dividends: Holders of Series X Convertible Preferred Stock are not entitled to receive any dividends except to the extent that dividends are paid on the Company's common stock. If dividends are paid on shares of common stock, holders of Series X Convertible Preferred Stock are entitled to participate in such dividends on an as-converted basis. Liquidation: Upon the liquidation, dissolution, or winding up of the company, each holder of Series X Convertible Preferred Stock will participate pari passu with any distribution of proceeds to holders of common stock. Voting: Shares of Series X Convertible Preferred Stock will generally have no voting rights, except as required by law and except that the consent of the holders of a majority of the outstanding Series X Convertible Preferred Stock will be required to amend the terms of the Series X Convertible Preferred Stock , if such action would adversely alter or change the preferences, rights, privileges or powers of, or restrictions provided for the benefit of the Series X Convertible Preferred Stock, or to increase or decrease (other than by conversion) the number of authorized shares of Series X Convertible Preferred Stock. The Company evaluated the Series X Convertible Preferred Stock for liability or equity classification under ASC 480, Distinguishing Liabilities from Equity , and determined that equity treatment was appropriate because the Series X Convertible Preferred Stock did not meet the definition of liability instruments defined thereunder as convertible instruments. Additionally, the Series X Convertible Preferred Stock is not redeemable for cash or other assets (i) on a fixed or determinable date, (ii) at the option of the holder, and (iii) upon the occurrence of an event that is not solely within control of the Company. As such, the Series X Convertible Preferred Stock is recorded as permanent equity. Common Stock The Company had 200,000,000 shares of common stock authorized as of December 31, 2021. Holders of outstanding shares of common stock are entitled to one vote for each share held of record on all matters submitted to a vote of the holders of common stock. Subject to the rights of the holders of any class of the Company’s capital stock having any preference or priority over common stock, the holders of common stock are entitled to receive dividends that are declared by the Company’s board of directors out of legally available funds. In the event of a liquidation, dissolution or winding-up, the holders of common stock are entitled to share ratably in the net assets remaining after payment of liabilities, subject to prior rights of preferred stock, if any, then outstanding. The common stock has no preemptive rights, conversion rights, redemption rights or sinking fund provisions, and there are no dividends in arrears or default. All shares of common stock have equal distribution, liquidation and voting rights, and have no preferences or exchange rights. Common Stock Warrants As of December 31, 2021 and 2020, warrants to purchase 12,517,328 shares of the Company's common stock were outstanding with a weighted average exercise price of $6.82 per share. The warrants had no intrinsic value at December 31, 2021 and 2020. The intrinsic value of a common stock warrant is the difference between the market price of the common stock at the measurement date and the exercise price of the warrant. Common Stock Reserved for Future Issuance Common stock reserved for future issuance is as follows (in common stock equivalent shares): December 31, 2021 2020 Common stock warrants 12,517,328 12,517,328 Series X Convertible Preferred stock 18,184,720 10,442,780 Stock options, RSUs and PRSUs issued and outstanding 9,470,178 6,787,033 Authorized for future stock awards 2,436,984 2,813,131 Awards available under the ESPP 680,228 521,986 Total 43,289,438 33,082,258

EQUITY INCENTIVE PLANS

EQUITY INCENTIVE PLANS	12 Months Ended
	Dec. 31, 2021
Share-based Payment Arrangement [Abstract]
EQUITY INCENTIVE PLANS	EQUITY INCENTIVE PLANS 2020 Inducement Incentive Plan and 2015 Equity Incentive Plan In December 2020, the Company's board of directors approved and adopted the 2020 Inducement Incentive Plan, or 2020 IIP. Under the 2020 IIP, the Company may grant stock options, stock appreciation rights, restricted stock, RSUs, and other awards to individuals who were not previously employees or directors of the Company, or who are returning to employment following a bona fide period of non-employment with the Company, as an inducement material to such persons entering into employment with the Company. In March 2015, the Company’s board of directors and stockholders approved and adopted the 2015 Equity Incentive Plan, or 2015 EIP. Under the 2015 EIP, the Company may grant stock options, stock appreciation rights, restricted stock, RSUs, and other awards to individuals who are employees, officers, directors or consultants of the Company. The number of shares of stock available for issuance under the 2015 EIP is automatically increased each January 1 by 4% of the outstanding number of shares of the Company’s common stock on the immediately preceding December 31 or such lesser number as determined by the Company’s board of directors. Terms of stock award agreements, including vesting requirements, are determined by the board of directors, subject to the provisions of the 2020 IIP and 2015 EIP. Stock options granted by the Company generally vest over a three 2015 Employee Stock Purchase Plan In March 2015, the Company’s board of directors and stockholders approved and adopted the 2015 Employee Stock Purchase Plan, or the ESPP. The number of shares of stock available for issuance under the ESPP will be automatically increased each January 1 by the lesser of (i) 1% of the outstanding number of shares of the Company’s common stock on the immediately preceding December 31, (ii) 490,336 shares, or (iii) such lesser number as determined by the Company’s board of directors. The ESPP allows substantially all employees to purchase the Company’s common stock through a payroll deduction at a price equal to 85% of the lower of the fair market value of the stock as of the beginning or the end of each purchase period. An employee’s payroll deductions under the ESPP are limited to 15% of the employee’s eligible compensation. During the years ended December 31, 2021, 2020 and 2019, 289,671, 280,139 and 242,501 shares, respectively, were issued pursuant to the ESPP. As of December 31, 2021, total unrecognized compensation expense related to the ESPP was approximately $0.6 million. This unrecognized compensation cost is expected to be recognized over approximately 0.7 years. Restricted Stock Units The following table summarizes RSU and PRSU activity during the year ended December 31, 2021: Number of Weighted Average Grant Date Fair Value Outstanding at December 31, 2020 428,235 $ 3.55 RSUs and PRSUs granted 932,875 2.27 RSUs and PRSUs vested (106,725) 3.40 RSUs and PRSUs canceled (80,298) 3.86 Outstanding at December 31, 2021 1,174,087 $ 2.53 The weighted-average grant date fair value of RSUs and PRSUs granted during the years ended December 31, 2020 and 2019 was $2.29 and $2.88, respectively, per share. The total fair value of RSUs and PRSUs vested during the years ended December 31, 2021, 2020 and 2019 was approximately $0.4 million, $0.3 million and $0.5 million respectively. At December 31, 2021, estimated unrecognized compensation expense related to RSUs and PRSUs granted was approximately $2.3 million. 2019 Option Exchange On November 20, 2019, the Company commenced an option exchange program pursuant to which it offered to certain employees the option to exchange some or all of their outstanding stock options, whether vested or unvested, for new stock options, or the Option Exchange. Stock options were eligible for exchange, or Eligible Options, if they had an exercise price greater than the greater of (i) $2.28 and (ii) the closing price of the Company's common stock on December 18, 2019, or the Exchange Date. An exchange ratio of 1 for 1 was applied to options held by eligible employees who were not executive officers for purposes of Section 16 of the Exchange Act as designated by the Board, or a Section 16 Officer, and an exchange ratio of 1.5 for 1 applied to options held by Section 16 officers. The Option Exchange closed on December 18, 2019. Eligible Options to purchase an aggregate of 1,656,379 shares of the Company's common stock, representing 60.4% of the total shares underlying the Eligible Options were exchanged for new options to purchase 1,529,814 of the Company's common stock at $2.45 per share, the closing price of the Company's common stock on the Exchange Date. All surrendered options were canceled effective as of the closing of the Option Exchange. These new options were granted pursuant to the 2015 EIP and vest over one Stock Options The following table summarizes stock option activity during the year ended December 31, 2021: Number of Weighted Weighted Total Aggregate Outstanding at December 31, 2020 6,358,798 $ 3.59 7.04 $ 55 Options granted 2,981,200 2.38 Options exercised (2,930) 1.98 Options canceled (1,040,977) 3.19 Outstanding at December 31, 2021 8,296,091 $ 3.21 6.31 $ — Vested and expected to vest at December 31, 2021 8,296,091 $ 3.21 6.31 $ — Exercisable at December 31, 2021 5,377,439 $ 3.71 4.87 $ — The intrinsic value of a stock option is the difference between the market price of the common stock at the measurement date and the exercise price of the option. The weighted-average grant date fair value of stock options granted during the years ended December 31, 2021, 2020 and 2019 was $1.42, $1.48 and $1.78, respectively, per share. As of December 31, 2021, total unrecognized share-based compensation expense related to unvested stock options was approximately $3.7 million. This unrecognized compensation cost is expected to be recognized over a weighted-average period of approximately 2.3 years. The following table summarizes the Black-Scholes option pricing model assumptions used to estimate the fair value of stock options granted to employees under the 2015 EIP and 2020 IIP and the shares purchasable under the 2015 ESPP during the periods presented: For the years ended December 31, 2021 2020 2015 EIP and 2020 IIP Risk-free interest rate 0.61% - 1.35% 0.30% - 1.66% Expected dividend yield 0% 0% Expected volatility 67% - 70% 82% - 85% Expected term (years) 5.27 - 6.08 5.27 - 6.08 2015 ESPP Risk-free interest rate 0.02% - 0.63% 0.08% - 0.17% Expected dividend yield 0% 0% Expected volatility 58% - 79% 65% - 105% Expected term (years) 0.50 - 2.00 0.50 - 2.00 Stock-based compensation expense recognized for restricted shares, RSUs, PRSUs, stock options, and the ESPP has been reported in the statements of operations and comprehensive loss as follows (in thousands): Years ended December 31, 2021 2020 2019 Research and development $ 1,908 $ 2,089 $ 2,502 General and administrative 2,106 2,001 2,571 Total $ 4,014 $ 4,090 $ 5,073

SIGNIFICANT AGREEMENTS AND CONT

SIGNIFICANT AGREEMENTS AND CONTRACTS	12 Months Ended
	Dec. 31, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
SIGNIFICANT AGREEMENTS AND CONTRACTS	SIGNIFICANT AGREEMENTS AND CONTRACTS Mundipharma Collaboration Agreement On September 3, 2019, the Company entered into the Mundipharma Collaboration Agreement with Mundipharma, a related party, for a strategic collaboration to develop and commercialize rezafungin in an intravenous formulation, or the Licensed Product for the treatment and prevention of invasive fungal infections. Under the Mundipharma Collaboration Agreement, the Company is responsible for leading the conduct of an agreed global development plan, or the Global Development Plan, that includes the Company’s ongoing Phase 3 pivotal clinical trial of the Licensed Product for the treatment of candidemia and/or invasive candidiasis, or the ReSTORE Trial, and the Company’s planned Phase 3 pivotal clinical trial of the Licensed Product for the prophylaxis of invasive fungal infections in adult allogeneic blood and marrow transplant recipients, or the ReSPECT Trial, as well as specified GLP-compliant non‑clinical studies and chemistry, manufacturing and controls, or CMC, development activities for the Licensed Product. Mundipharma is responsible for performing all development activities, other than Global Development Plan activities, that may be necessary to obtain and maintain regulatory approvals for the Licensed Product in the Mundipharma Territory, at Mundipharma’s sole cost. Pursuant to the Mundipharma Collaboration Agreement, the Company granted Mundipharma an exclusive, royalty‑bearing license to develop, register and commercialize the Licensed Product outside of the U.S. and Japan, or the Mundipharma Territory, subject to the Company’s retained right to lead a global development program for the Licensed Product in both the Mundipharma Territory and in the U.S. and Japan, or the Company Territory, as described below. The Company also granted Mundipharma an option to obtain exclusive licenses to develop, register and commercialize rezafungin in a formulation for subcutaneous administration, or Subcutaneous Product, and in formulations for other modes of administration, or Other Products, in the Mundipharma Territory, subject to similar retained rights of the Company to conduct mutually agreed global development activities for such products. In addition, the Company granted Mundipharma a co‑exclusive, worldwide license to manufacture the Licensed Product and rezafungin. Until the seventh anniversary of the first commercial sale of the Licensed Product in the Mundipharma Territory, each party has granted the other party an exclusive, time-limited right of first negotiation to obtain a license to any anti-fungal product (other than Licensed Product, Subcutaneous Product and Other Products) that such party proposes to out-license in the other party’s territory. However, in the event of the acquisition of a party by a third party, this right of first negotiation will not apply to any such anti‑fungal product of the acquiring third party prior to consummation of the acquisition of such party, acquired by such acquiring third party from another third party after consummation of the acquisition of such party, or developed internally by the acquiring third party, either before or after consummation of the acquisition of such party, without the use of, reliance upon or reference to any technology of the acquired party that is licensed to the other party under the Mundipharma Collaboration Agreement, any technology of the other party that is licensed to the acquired party under the Mundipharma Collaboration Agreement, or any technology jointly developed by the parties pursuant to the Mundipharma Collaboration Agreement. The Company retains the exclusive right to develop, register and commercialize the Licensed Product, Subcutaneous Product and Other Products in the Company Territory, and Mundipharma has granted the Company certain licenses under Mundipharma-controlled technology and jointly-developed technology to develop, register and commercialize Licensed Product, Subcutaneous Product and Other Products in the Company Territory and to manufacture such products and rezafungin worldwide. The parties have agreed to share equally (50/50) the costs of Global Development Plan activities, or Global Development Costs, subject to a cap on Mundipharma’s Global Development Cost share of $31.2 million. The Company would receive additional financial support for Global Development Plan activities through a near-term milestone payment by Mundipharma of $11.1 million. Mundipharma is entitled to credit the full amount of this milestone payment toward future royalties payable to the Company, subject to a limit on the amount by which royalty payments to the Company may be reduced in any quarter. If Mundipharma has not fully credited the amount of such milestone payment toward royalties payable to the Company before the earlier of (i) December 31, 2024 and (ii) termination of the Mundipharma Collaboration Agreement by Mundipharma, the Company will be obligated to refund the uncredited portion of such milestone payment to Mundipharma on the earlier of such dates. The total potential transaction value is $568.4 million, including an equity investment, an up-front payment, global development funding, and certain development, regulatory, and commercial milestones. The Company is also eligible for double-digit royalties in the teens on tiers of annual net sales. Either party may terminate the Mundipharma Collaboration Agreement for uncured material breach by the other party. Mundipharma may terminate the Mundipharma Collaboration Agreement at will, provided that if Mundipharma terminates the Mundipharma Collaboration Agreement in its entirety prior to the last visit of the last patient in both the ReSPECT Trial and the ReSTORE Trial, Mundipharma will continue to be liable for its share of Global Development Costs as described above. The Company may terminate the Mundipharma Collaboration Agreement if Mundipharma or any of its affiliates or sublicensees, directly or indirectly through any third party, commences any interference or opposition proceeding with respect to, challenges the validity or enforceability of, or opposes any extension of or the grant of a supplementary protection certificate with respect to, any of the Company's patent rights licensed to Mundipharma, or upon an insolvency event of Mundipharma. Revenue Recognition The Company determined the transaction price is equal to the up-front fee of $30.0 million plus the research and development funding of $31.2 million. The common stock issued pursuant to the Mundipharma Stock Purchase Agreement was determined to be issued at fair market value after applying a lack of marketability discount as Mundipharma received restricted shares. Therefore, no additional premium or discount was allocated to the transaction price of the Mundipharma Collaboration Agreement for the share issuance. The transaction price was allocated to the performance obligations on the basis of the relative stand-alone selling price estimated for each performance obligation. In estimating the stand-alone selling price for each performance obligation, the Company developed assumptions that require judgment and included forecasted revenues, expected development timelines, discount rates, probabilities of technical and regulatory success and costs for manufacturing clinical supplies. A description of the distinct performance obligations identified under the Mundipharma Collaboration Agreement, as well as the amount of revenue allocated to each distinct significant performance obligation, is as follows: Licenses of Intellectual Property. The license to the Company’s intellectual property, bundled with the associated know-how, represents a distinct performance obligation. The license and associated know-how was transferred to Mundipharma during September 2019, therefore the Company recognized the full revenue related to this performance obligation in the amount of $17.9 million in September 2019 as collaboration revenue in its consolidated statements of operations and comprehensive loss. Research and Development Services. The Company and Mundipharma share equally in the costs of ongoing rezafungin clinical development in the Licensed Territory up to the specified cap, which represents a distinct performance obligation. The Company records these cost-sharing payments due from Mundipharma as collaboration revenue. The Company concluded that progress towards completion of the performance obligation related to the research and development services is best measured in an amount proportional to the research and development expenses incurred and the total estimated research and development expenses. Clinical Supply Services. The Company's initial obligation to supply rezafungin for ongoing clinical development in the Licensed Territory represents a distinct performance obligation. The Company concluded that progress towards completion of the performance obligations related to the clinical supply services is best measured in an amount proportional to the clinical supply services expenses incurred and the total estimated clinical supply services. Milestone Payments. The Company determined that as of December 31, 2021, all the potential milestone payments are probable of significant revenue reversal as their achievement is highly dependent on factors outside the Company's control or are otherwise constrained under the variable consideration guidance. Therefore, these payments have been fully constrained and are therefore not included in the transaction price. At the end of each subsequent reporting period, the Company will re-evaluate the probability of achievement of each milestone and any related constraint. In November 2020, the Company achieved a $11.1 million milestone under the Mundipharma Collaboration Agreement, which is recorded as long-term deferred revenue as of December 31, 2021 because the rights to consideration is not expected to be satisfied within one year. The Company received payment for this milestone in January 2021. Mundipharma is entitled to credit the full amount of this milestone payment toward future royalties payable to the Company, subject to a limit on the amount by which royalty payments to the Company may be reduced in any quarter. If Mundipharma has not fully credited the amount of such milestone payment toward royalties payable to the Company before the earlier of (i) December 31, 2024 and (ii) termination of the Mundipharma Collaboration Agreement by Mundipharma, the Company will be obligated to refund the uncredited portion of such milestone payment to Mundipharma on the earlier of such dates. In December 2021, the Company achieved a $2.8 million milestone under the Mundipharma Collaboration Agreement that the Company deems to be tied to all the performance obligations identified in the original agreement. Revenue associated with the milestone has been allocated proportionately to the original transaction price which was allocated to the performance obligations on the basis of the relative stand-alone selling price estimated for each performance obligation. In conjunction with the performance obligations already delivered, revenue of $2.0 million was recognized in December 2021 based on the progress of these performance obligations, and $0.8 million is recorded as deferred revenue as of December 31, 2021 and will be recognized as revenue over the remaining progress of these performance obligations. The Company received payment for this milestone in January 2022. No revenue related to milestones was recognized during the years ended December 31, 2020 and 2019. Royalties. As the license is deemed to be the predominant item to which sales-based royalties relate, the Company will recognize revenue when the related sales occur. No royalty revenue was recognized during the years ended December 31, 2021, 2020 and 2019. Janssen Collaboration Agreement On March 31, 2021, the Company and Janssen entered into the Janssen Collaboration Agreement to develop and commercialize one or more DFCs (previously called Antiviral Drug Conjugates, or AVCs) based on the Company's Cloudbreak platform, for the prevention and treatment of influenza, including CD388 and CD377, or the Products. The effectiveness of the Janssen Collaboration Agreement, including the effectiveness of the terms and conditions described below, was subject to the expiration or earlier termination of all applicable waiting periods under the Hart-Scott-Rodino Antitrust Improvements Act of 1976, as amended, or HSR. HSR clearance was obtained on May 12, 2021 and the Janssen Collaboration Agreement became effective on the same date. Collaboration . The Company and Janssen will collaborate in the research, preclinical development and early clinical development of CD388 or another mutually-agreed influenza DFC development candidate, or, in each case, the Development Candidate, under a mutually-agreed research and development plan, or the Research Plan, with the objective of advancing such Development Candidate through the completion of mutually-agreed Phase 1 clinical trials and the first Phase 2 clinical trial, or the Phase 2 Study. Unless otherwise agreed by the parties, the Company will be responsible for performing, or having performed, all IND-enabling studies and clinical trials under the Research Plan, and the Company will be the IND holder for the Research Plan clinical trials. Both parties will be responsible for conducting certain specified chemistry, manufacturing and controls development activities under the Research Plan. Janssen will be solely responsible, and reimburse the Company, for internal full-time equivalent and out-of-pocket costs incurred by the Company in performing Research Plan activities in accordance with a mutually-agreed budget. In addition, upon the effectiveness of the Janssen Collaboration Agreement, Janssen will also reimburse the Company for certain costs incurred by the Company in independently performing certain research and development activities from the execution of the Janssen Collaboration Agreement until its effectiveness. Within 90 days after delivery by the Company to Janssen of results of the Phase 2 Study and all then-available data from other clinical trials of the Development Candidate conducted under the Research Plan, or the Election Period, Janssen will be obligated to notify the Company of Janssen’s election to proceed with further clinical development of Products, such notice, an Election to Proceed Notice. If Janssen fails to deliver an Election to Proceed Notice prior to expiration of the Election Period, the Company will have the right to terminate the Janssen Collaboration Agreement upon written notice to Janssen. If Janssen provides an Election to Proceed Notice prior to expiration of the Election Period, then the parties will continue any then-ongoing Research Plan activities to completion, and Janssen will otherwise be solely responsible for the development, manufacture and commercialization of Products, at Janssen’s sole expense. Licenses . Upon the effectiveness of the Janssen Collaboration Agreement, the Company granted Janssen an exclusive, worldwide, royalty-bearing license to develop, register and commercialize Products, subject to the Company’s retained right to conduct Research Plan activities as described above. In addition, the Company granted Janssen an exclusive right of first negotiation until December 31, 2021, to negotiate and enter into a separate definitive agreement pursuant to which the parties would collaborate in the research and development of DFCs for the treatment or prevention of respiratory syncytial virus. This right of first negotiation expired on December 31, 2021. Non-Compete Covenant . The Company will covenant that, except for the performance of Research Plan activities, from the effectiveness of the Janssen Collaboration Agreement until the fifth anniversary of the completion of all Research Plan activities and the Company’s delivery to Janssen of all Research Plan deliverables, the Company and its affiliates will not directly or indirectly (including through any third-party contractor or through or in collaboration with any third-party licensee) develop, file any IND or application for marketing approval for, or commercialize any DFC that binds influenza or influenza viral proteins at therapeutic levels, except that the Company has the right to conduct limited internal research of such DFCs for the purposes of generating data to support patent filings and improving and further developing the Company’s DFC technology more broadly. The Company’s non-compete covenant described above will not apply to any DFC that demonstrates high specificity for a virus other than the influenza virus and does not possess significant activity against the influenza virus. Financial Terms . Upon the effectiveness of the Janssen Collaboration Agreement, Janssen paid the Company an upfront payment of $27.0 million. As of the execution of the Janssen Collaboration Agreement, the Company is entitled to reimbursement by Janssen of up to $58.2 million in research and development costs incurred in conducting Research Plan activities. The Company will also be entitled to receive up to an additional $695.0 million in development, regulatory and commercial milestone payments, as well as royalties on tiers of annual net sales of Products at rates from the mid-single digits to the high-single digits. Termination . In addition to the Company’s right to terminate the Janssen Collaboration Agreement for Janssen’s failure to deliver the Election to Proceed Notice prior to expiration of the Election Period, the Janssen Collaboration Agreement includes standard termination provisions upon material breach, insolvency or safety concerns. In addition, Janssen may terminate the Janssen Collaboration Agreement for convenience as follows: • prior to the completion of all Research Plan activities and the Company’s delivery to Janssen of all Research Plan deliverables, upon 90 days’ written notice to the Company, provided that if any clinical trial under the Research Plan is ongoing at the time of such termination, such clinical trial will be completed in accordance with the terms of the Janssen Collaboration Agreement; • after completion of the Phase 2 Study and before expiration of the Election Period, immediately upon written notice to the Company; or • after delivery of the Election to Proceed Notice, upon 90 days’ written notice to the Company, which termination may be of the Janssen Collaboration Agreement in its entirety or on a country-by-country or Product-by-Product basis. Revenue Recognition The Company determined the transaction price is equal to the up-front fee of $27.0 million plus the research and development funding of $60.6 million. The transaction price was allocated to the performance obligations on the basis of the relative stand-alone selling price estimated for each performance obligation. In estimating the stand-alone selling price for each performance obligation, the Company developed assumptions that require judgment and included forecasted revenues, expected development timelines, discount rates, probabilities of technical and regulatory success, costs to continue the research and development efforts and costs for manufacturing clinical supplies. A description of the distinct performance obligations identified under the Janssen Collaboration Agreement, as well as the amount of revenue allocated to each distinct significant performance obligation, is as follows: Licenses of Intellectual Property. The license to the Company’s intellectual property, bundled with the associated know-how, represents a distinct performance obligation. The license and associated know-how was transferred to Janssen in May 2021, therefore the Company recognized the revenue related to this performance obligation in the amount of $27.0 million in May 2021 as collaboration revenue in its consolidated statements of operations and comprehensive loss. Research and Development Services. The research and development services to be performed represents a distinct performance obligation. The Company records payments due from Janssen as collaboration revenue. The Company recognizes revenue based on actual amounts incurred as the underlying services are provided and billed at fair value. Clinical Supply Services. The Company's initial obligation to supply drug supply for ongoing development represents a distinct performance obligation. The Company recognizes revenue based on actual amounts incurred as the underlying services are provided and billed at fair value. Milestone Payments. The Company determined that as of the latest financial statement date all the potential milestone payments are probable of significant revenue reversal as their achievement is highly dependent on factors outside the Company's control or are otherwise constrained under the variable consideration guidance. Therefore, these payments have been fully constrained and are not included in the transaction price. At the end of each subsequent reporting period, the Company will re-evaluate the probability of achievement of each milestone and any related constraint. No revenue related to milestones was recognized during the year ended December 31, 2021. Royalties. As the license is deemed to be the predominant item to which sales-based royalties relate, the Company will recognize revenue when the related sales occur. No royalty revenue was recognized during the year ended December 31, 2021. Contract Liabilities The following table presents a summary of the activity in the Company's contract liabilities (recorded as deferred revenue on the balance sheet) during the year ended December 31, 2021 (in thousands): Opening balance, December 31, 2020 $ 25,010 Payments received 17,673 Payment receivable 781 Revenue from performance obligations satisfied during reporting period (11,131) Closing balance, December 31, 2021 $ 32,333 Current portion of deferred revenue $ 13,920 Long-term portion of deferred revenue 18,413 Total deferred revenue, December 31, 2021 $ 32,333 As of December 31, 2021, the aggregate transaction price allocated to performance obligations that are unsatisfied is $17.9 million and $51.3 million under the Mundipharma Collaboration Agreement and Janssen Collaboration Agreement, respectively. These amounts are expected to be recognized over 2.0 years which represent the remaining research periods under the Mundipharma Collaboration Agreement and Janssen Collaboration Agreement. As of December 31, 2021, the Company recorded $2.8 million and $2.4 million in accounts receivable associated with the Mundipharma Collaboration Agreement and Janssen Collaboration Agreement, respectively. As of December 31, 2020, the Company recorded $11.1 million in accounts receivable for milestone achieved under the Mundipharma Collaboration Agreement that was received in January 2021. The following table presents our contract revenues disaggregated by timing of revenue recognition (in thousands): Years Ended December 31 2021 2020 2019 Point in Time Over Time Point in Time Over Time Point in Time Over Time Revenue from Mundipharma Collaboration Agreement: Licenses of Intellectual Property $ 813 $ — $ — $ — $ 17,861 $ — Research and Development Services — 12,069 — 10,513 — 2,670 Clinical Supply Services — 315 — 1,554 — 384 Total revenue from Mundipharma Collaboration Agreement $ 813 $ 12,384 $ — $ 12,067 $ 17,861 $ 3,054 Revenue from Janssen Collaboration Agreement: License of Intellectual Property $ 27,000 $ — $ — $ — $ — $ — Research and Development Services — 5,271 — — — — Clinical Supply Services — 4,104 — — — — Total revenue from Janssen Collaboration Agreement $ 27,000 $ 9,375 $ — $ — $ — $ —

INCOME TAXES

INCOME TAXES	12 Months Ended
	Dec. 31, 2021
Income Tax Disclosure [Abstract]
INCOME TAXES	INCOME TAXES The Company accounts for income taxes under ASC 740. Deferred income tax assets and liabilities are determined based upon differences between financial reporting and tax bases of assets and liabilities and are measured using the enacted tax rates and laws that will be in effect when the differences are expected to reverse. The following table provides a reconciliation between income taxes computed at the federal statutory rate and the provision for income taxes (in thousands): Years Ended December 31, 2021 2020 2019 Federal income taxes at 21% for 2021, 2020 and 2019 $ (8,918) $ (15,142) $ (8,629) State income tax, net of federal benefit (1,426) (469) (1,899) Tax effect on nondeductible expenses 339 486 561 Research credits (2,487) (2,956) (4,141) Rate change (30) 344 (664) Change in valuation allowance 11,789 15,912 13,692 Reserve for uncertain tax positions 622 739 1,035 162m deferred tax asset limitation 76 857 — Other 35 229 45 Income tax expense $ — $ — $ — Significant components of the Company’s net deferred tax assets are as follows (in thousands): Years Ended December 31, 2021 2020 Deferred tax assets: Net operating losses $ 68,146 $ 62,238 Research credits 21,195 19,330 Intangibles 197 221 Stock compensation 2,478 2,007 Lease liability 595 224 Other 4,337 795 Total deferred tax assets 96,948 84,815 Less valuation allowance (96,397) (84,608) Deferred tax assets, net of valuation allowance 551 207 Deferred tax liabilities: Right-of-use assets (551) (207) Total deferred tax liabilities (551) (207) Net deferred tax assets $ — $ — At December 31, 2021, the Company had federal and state tax net operating loss carryforwards of approximately $306.8 million and $234.2 million, respectively. The federal and state net operating loss carryforwards begin to expire in 2033 and 2029, respectively, unless previously utilized. The Company also has federal research and development and orphan drug credit carryforwards totaling $24.9 million and state research and development credit carryforwards totaling $4.4 million. The federal research and development credit and orphan drug credit carryforwards begin to expire in 2033, unless previously utilized. The state research and development credit carryforwards begin to expire in 2029, with the exception of $4.4 million which have no expiration date. Management assesses the available positive and negative evidence to estimate if sufficient future taxable income will be generated to use the existing deferred tax assets. Based on the weight of all evidence, including a history of operating losses, management has determined that it is more likely than not that the net deferred tax assets will not be realized. A valuation allowance of $96.4 million and $84.6 million as of December 31, 2021 and 2020, respectively, has been established to offset the deferred tax assets as realization of such assets is uncertain. Future utilization of the Company’s net operating loss and research and development credits carryforwards to offset future taxable income may be subject to an annual limitation, pursuant to Internal Revenue Code (IRC) Sections 382 and 383, as a result of ownership changes that may have occurred or that could occur in the future. An ownership change occurs when a cumulative change in ownership of more than 50% occurs within a three-year period. The Company has not completed an IRC Section 382/383 analysis regarding the limitation of net operating loss and research and development credit carryforwards. On March 27, 2020, the Coronavirus Aid, Relief, and Economic Security Act, or the CARES Act, was enacted and signed into law in response to COVID-19. The CARES Act, among other things, included several significant provisions that impacted corporate taxpayers’ accounting for income taxes. Prior to the enactment of the CARES Act, the 2017 Tax Cuts and Jobs Act generally eliminated the ability to carryback net operating losses, or NOLs, and permitted the NOLs arising in tax years beginning after December 31, 2017 to be carried forward indefinitely, limited to 80% of the taxpayer’s income. The CARES Act amended the NOL rules, suspending the 80% limitation on the utilization of NOLs generated after December 31, 2017 and before January 1, 2021. Additionally, the CARES Act allows corporate NOLs arising in taxable years beginning after December 31, 2017 and before January 1, 2021, to be carried back to each of the five taxable years preceding the taxable year of the loss. Also, the CARES Act allows companies to defer making certain payroll tax payments until future years. The Company did not have a financial statement impact from the enactment of the CARES Act. The Company recognizes a tax benefit from an uncertain tax position when it is more likely than not that the position will be sustained upon examination, including resolutions of any related appeals or litigation processes, based on the technical merits. Income tax positions must meet a more likely than not recognition at the effective date to be recognized. At December 31, 2021, 2020 and 2019, the unrecognized tax benefits recorded were approximately $24.0 million, $23.3 million and $22.6 million, respectively. Approximately $19.7 million of the unrecognized tax benefits would reduce the Company's annual effective tax rates, if recognized, subject to the valuation allowances. The Company does not anticipate a significant change in the unrecognized tax benefits within the next 12 months. A reconciliation of the beginning and ending amount of gross unrecognized tax benefits for 2021, 2020 and 2019 is as follows (in thousands): Years Ended December 31, 2021 2020 2019 Balance as of the beginning of the year $ 23,335 $ 22,558 $ 16,524 Increases related to current year tax positions 655 777 1,074 Increases related to prior year tax positions — — 4,960 Balance as of the end of the year $ 23,990 $ 23,335 $ 22,558 The Company files tax returns as prescribed by the tax laws of the jurisdictions in which it operates. In the normal course of business, the Company is subject to examination by the U.S. and state jurisdictions where applicable. There are currently no pending income tax examinations. The Company’s tax years from inception in 2013 are subject to examination by the federal and state tax authorities due to the carryforward of unutilized net operating losses and research and development credits. The Company’s practice is to recognize interest and penalties related to income tax matters in income tax expense. The Company has not recognized interest or penalties since inception.

COMMITMENTS AND CONTINGENCIES

COMMITMENTS AND CONTINGENCIES	12 Months Ended
	Dec. 31, 2021
Commitments and Contingencies Disclosure [Abstract]
COMMITMENTS AND CONTINGENCIES	COMMITMENTS AND CONTINGENCIES Litigation From time to time, the Company may be involved in various lawsuits, legal proceedings, or claims that arise in the ordinary course of business. Management believes there are no claims or actions pending against the Company at December 31, 2021 which will have, individually or in the aggregate, a material adverse effect on its business, liquidity, financial position or results of operations. Litigation, however, is subject to inherent uncertainties, and an adverse result in such matters may arise from time to time that may harm the Company’s business. Lease Obligations The Company adopted ASU 2016-02, "Leases," on January 1, 2019, which resulted in the recognition of operating leases on the balance sheet. The Company determines if a contract contains a lease at inception and recognizes operating lease right-of-use assets and operating lease liabilities based on the present value of the future minimum lease payments at the commencement date. As the Company's leases do not provide an implicit rate, management develops incremental borrowing rates based on the information available at the commencement date in determining the present value of future payments. Lease agreements that have lease and non-lease components are accounted for as a single lease component. Lease expense is recognized on a straight-line basis over the lease term. The Company's single lease upon adoption is for laboratory and office space in San Diego, California and was entered into in June 2014. Amendments for additional space were entered into in February 2015, March 2015 and August 2015. On July 14, 2021, the Company entered into a sixth amendment to its lease with Nancy Ridge Technology Center, L.P. which extended the term of the lease by an additional 24 months and increases the base rent to $103,733 per month effective January 1, 2022, subject to 3% increases every January. The lease expires on December 31, 2023 with options for two individual two-year extensions, which have not been exercised, and remain in effect and available to the Company. As of December 31, 2021, the Company was not reasonably certain that it would exercise the extension options, and therefore did not include these options in the determination of the total lease term for accounting purposes. The incremental borrowing rate used in measuring the Company's lease liability was 10.8%. The following table presents information about the amount, timing and uncertainty of cash flows arising from the Company's operating lease as of December 31, 2021 (in thousands): 2022 $ 1,359 2023 1,400 Total undiscounted operating lease payments 2,759 Less: Imputed interest (289) Present value of lease payments $ 2,470 The balance sheet classification of the Company's operating lease is as follows (in thousands): Balance Sheet Classification: Operating lease right-of-use asset $ 2,287 Current portion of lease liability $ 1,148 Lease liability 1,322 Total operating lease liability $ 2,470 As of December 31, 2021, the weighted average remaining lease term was 2 years. Cash paid for amounts included in the present value of operating lease liabilities was $1.0 million for the year ended December 31, 2021. Operating lease costs were $1.2 million, $1.0 million and $1.0 million for the years ended December 31, 2021, 2020 and 2019, respectively. These costs are primarily related to the Company's long-term operating lease, but also include immaterial amounts for variable leases and short-term leases with terms greater than 30 days. Contractual Obligations The Company enters into contracts in the normal course of business with vendors for research and development activities, manufacturing, and professional services. These contracts generally provide for termination either on notice or after a notice period.

SUMMARY OF SIGNIFICANT ACCOUN_2

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)	12 Months Ended
	Dec. 31, 2021
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The Company has a limited operating history and the sales and income potential of the Company’s business and market are unproven. The Company has experienced net losses and negative cash flows from operating activities since its inception. At December 31, 2021, the Company had an accumulated deficit of $377.2 million. The Company expects to continue to incur net losses into the foreseeable future. Successful transition to attaining profitable operations is dependent upon achieving a level of revenues adequate to support the Company’s cost structure. At December 31, 2021, the Company had cash, cash equivalents and restricted cash of $62.3 million. Based on the Company’s current business plan, management believes that existing cash and cash equivalents will not be sufficient to fund the Company’s obligations for twelve months from the issuance of these financial statements. The Company’s ability to execute its operating plan depends on its ability to obtain additional funding through equity offerings, debt financings or potential licensing and collaboration arrangements. The accompanying consolidated financial statements have been prepared assuming the Company will continue as a going concern, which contemplates the realization of assets and settlement of liabilities in the normal course of business. However, the Company’s current working capital, anticipated operating expenses and net losses and the uncertainties surrounding its ability to raise additional capital as needed, as discussed below, raise substantial doubt about its ability to continue as a going concern for a period of one year following the date that these financial statements are issued. The consolidated financial statements do not include any adjustments for the recovery and classification of assets or the amounts and classification of liabilities that might be necessary should the Company be unable to continue as a going concern. The Company plans to continue to fund its losses from operations through cash and cash equivalents on hand, as well as through future equity offerings, debt financings, other third party funding, and potential licensing or collaboration arrangements. There can be no assurance that additional funds will be available when needed from any source or, if available, will be available on terms that are acceptable to the Company. Even if the Company raises additional capital, it may also be required to modify, delay or abandon some of its plans which could have a material adverse effect on the Company’s business, operating results and financial condition and the Company’s ability to achieve its intended business objectives. Any of these actions could materially harm the Company’s business, results of operations and future prospects. In addition to the foregoing, the Company is monitoring closely the impact of the COVID-19 pandemic on its business and has taken steps designed to protect the health and safety of its employees while continuing its operations. Given the level of uncertainty regarding the duration and impact of the COVID-19 pandemic on capital markets and the U.S. economy, the Company is currently unable to assess the impact of the COVID-19 pandemic on its future access to capital. The Company is continuing to monitor the spread of COVID-19 and its potential impact on the Company's operations. The full extent to which the COVID-19 pandemic will impact the Company's business, results of operations, financial condition, clinical trials, and preclinical research will depend on future developments that are highly uncertain, including actions taken to contain or treat COVID-19 and their effectiveness, as well as the economic impact on national and international markets.
Basis of Consolidation	Basis of Consolidation The consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries. All significant intercompany accounts and transactions have been eliminated in consolidation.
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with U.S. generally accepted accounting principles, or GAAP, requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities at the date of the financial statements, and the reported amounts of expenses during the reporting period. The Company evaluates its estimates and assumptions on an ongoing basis. The most significant estimates in the Company’s consolidated financial statements relate to estimating the fair value of the Company’s stock options, estimated collaboration expenses and incurred expenses related to the Mundipharma Collaboration Agreement and Janssen Collaboration Agreement (as defined below), certain accruals, including those related to nonclinical and clinical activities, and the Standalone Selling Price of performance obligations associated with license agreements. Although the estimates are based on the Company’s knowledge of current events, comparable companies, and actions it may undertake in the future, actual results may ultimately materially differ from these estimates and assumptions.
Segment Information	Segment Information Operating segments are identified as components of an enterprise about which separate discrete financial information is available for evaluation by the chief operating decision maker, the Chief Executive Officer, in making decisions regarding resource allocation and assessing performance. The Company views its operations and manages its business as one operating segment.
Cash, Cash Equivalents, and Restricted Cash	Cash, Cash Equivalents, and Restricted Cash The Company considers all short-term investments purchased with a maturity of three months or less when acquired to be cash equivalents. Restricted cash represents cash that the Company is required to maintain on hand in order to maintain compliance with an operating covenant in the Third Amendment to the Company's Loan Agreement with Pacific Western Bank. See Note 5 for additional information.
Accounts Receivable	Accounts Receivable Accounts receivable are recorded at their net invoice value and are not interest bearing. The Company reserves specific receivables when collectability is no longer probable. These reserves are re-evaluated on a regular basis and are adjusted, as needed. Once a receivable is deemed to be uncollectable, such balance is recorded as an allowance for credit losses. No such allowance existed at December 31, 2021 or 2020.
Property and Equipment	Property and Equipment The Company records property and equipment at cost, which consists of lab equipment, computer equipment and software, office equipment, furniture and fixtures and leasehold improvements. Property and equipment is depreciated using the straight-line method over the estimated useful lives (generally three
Concentration of Credit Risk	Concentration of Credit Risk The Company’s financial instruments that are exposed to concentrations of credit risk consist primarily of cash and cash equivalents. The Company maintains deposits in government insured financial institutions in excess of government insured limits. The Company invests its cash balances in financial institutions that it believes have high credit quality, has not experienced any losses on such accounts and does not believe it is exposed to significant credit risk.
Patent Costs	Patent Costs The Company expenses all costs as incurred in connection with patent applications (including direct application fees, and the legal and consulting expenses related to making such applications) and such costs are included in general and administrative expenses in the accompanying statements of operations and comprehensive loss.
Income Taxes	Income Taxes The Company follows the Financial Accounting Standards Board, or FASB, Accounting Standards Codification , or ASC, 740, Income Taxes , or ASC 740, in reporting deferred income taxes. ASC 740 requires a company to recognize deferred tax assets and liabilities for expected future income tax consequences of events that have been recognized in the Company’s consolidated financial statements. Under this method, deferred tax assets and liabilities are determined based on temporary differences between financial statement carrying amounts and the tax basis of assets and liabilities using enacted tax rates in the years in which the temporary differences are expected to reverse. Valuation allowances are provided if, based on the weight of available evidence, it is more likely than not that some or all of the deferred tax assets will not be realized. The Company accounts for uncertain tax positions pursuant to ASC 740, which prescribes a recognition threshold and measurement process for financial statement recognition of uncertain tax positions taken or expected to be taken in a tax return. If the tax position meets this threshold, the benefit to be recognized is measured as the tax benefit having the highest likelihood of being realized upon ultimate settlement with the taxing authority. The Company recognizes interest accrued related to unrecognized tax benefits and penalties in the provision for income taxes.
Revenue Recognition	Revenue Recognition The Company recognizes revenue is accordance with ASC Topic 606, Revenue from Contracts with Customers , or Topic 606, which applies to all contracts with customers, except for contracts that are within the scope of other standards, such as leases, insurance, collaboration arrangements and financial instruments. Under Topic 606, an entity recognizes revenue when its customer obtains control of promised goods or services, in an amount that reflects the consideration that the entity expects to receive in exchange for those goods or services. To determine revenue recognition for arrangements that an entity determines are within the scope of Topic 606, the entity performs the following five steps: (i) identify the contract(s) with a customer; (ii) identify the performance obligations in the contract; (iii) determine the transaction price; (iv) allocate the transaction price to the performance obligations in the contract; and (v) recognize revenue when (or as) the entity satisfies a performance obligation. The Company only applies the five-step model to contracts when it is probable that the entity will collect the consideration it is entitled to in exchange for the goods or services it transfers to the customer. At contract inception, once the contract is determined to be within the scope of Topic 606, the Company assesses the goods or services promised within each contract and determines those that are performance obligations, and assesses whether each promised good or service is distinct. The Company then recognizes as revenue the amount of the transaction price that is allocated to the respective performance obligation when (or as) the performance obligation is satisfied. In a contract with multiple performance obligations, the Company must develop estimates and assumptions that require judgment to determine the underlying stand-alone selling price for each performance obligation, which determines how the transaction price is allocated among the performance obligations. The estimation of the stand-alone selling price(s) may include estimates regarding forecasted revenues or costs, development timelines, discount rates, and probabilities of technical and regulatory success. The Company evaluates each performance obligation to determine if it can be satisfied at a point in time or over time. Any change made to estimated progress towards completion of a performance obligation and, therefore, revenue recognized will be recorded as a change in estimate. In addition, variable consideration must be evaluated to determine if it is constrained and, therefore, excluded from the transaction price. If a license to the Company’s intellectual property is determined to be distinct from the other performance obligations identified in a contract, the Company recognizes revenues from the transaction price allocated to the license when the license is transferred to the licensee and the licensee is able to use and benefit from the license. For licenses that are bundled with other promises, the Company utilizes 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 for purposes of recognizing revenue from the allocated transaction price. The Company evaluates the measure of progress at each reporting period and, if necessary, adjusts the measure of performance and related revenue or expense recognition as a change in estimate. At the inception of each arrangement that includes milestone payments, the Company evaluates whether the milestones are considered probable of being reached. If it is probable that a significant revenue reversal would not occur, the associated milestone value is included in the transaction price. Milestone payments that are not within the Company’s or a collaboration partner’s control, such as regulatory approvals, are generally 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 milestones that are within its or a collaboration partner’s control, such as operational developmental 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 will affect collaboration revenues and earnings in the period of adjustment. Revisions to the Company’s estimate of the transaction price may also result in negative collaboration revenues and earnings in the period of adjustment. For arrangements that include sales-based royalties, including commercial milestone payments based on the level of sales, and a license is deemed to be the predominant item to which the royalties relate, the Company will recognize 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 from collaborative arrangements. In September 2019, the Company entered into a Collaboration and License Agreement, or the Mundipharma Collaboration Agreement, with Mundipharma Medical Company, or Mundipharma. The Company concluded that there were three significant performance obligations under the Mundipharma Collaboration Agreement: the license, the research and development services, and the clinical supply services, and that the obligations are distinct from each other. Revenue associated with the license was recognized upon delivery in September 2019. In March 2021, the Company entered into an exclusive worldwide license and collaboration agreement, or the Janssen Collaboration Agreement, with Janssen. The Company concluded that there were three significant performance obligations under the Janssen Collaboration Agreement: the license, the research and development services, and the clinical supply services, and that the obligations are distinct from each other. Revenue associated with the license was recognized upon delivery in May 2021. The Company concluded that progress towards completion of the research and development and clinical supply performance obligations related to the Mundipharma Collaboration Agreement is best measured in an amount proportional to the collaboration expenses incurred and the total estimated collaboration expenses. The Company periodically reviews and updates the estimated collaboration expenses, when appropriate, which may adjust revenue recognized for the period. While such changes to the Company’s estimates have no impact on the Company’s reported cash flows, the amount of revenue recorded in the period could be materially impacted. Revenue from research and development services for the Janssen Collaboration Agreement is recognized based on actual amounts billed as the underlying services are provided and billed at market rates. The transaction prices to be recognized as revenue under both the Mundipharma Collaboration Agreement and the Janssen Collaboration Agreement consist of upfront payments and estimated reimbursable research and development and clinical supply costs. Potential future payments for variable consideration, such as clinical, regulatory or commercial milestones, will be recognized when it is probable that, if recorded, a significant reversal will not take place. Potential future royalty payments will be recorded as revenue when the associated sales occur. See Note 8 for additional information.
Research and Development Costs	Research and Development Costs Research and development expenses consist of wages, benefits and stock-based compensation charges for research and development employees, scientific consultant fees, facilities and overhead expenses, laboratory supplies, manufacturing expenses, and nonclinical and clinical trial costs. The Company accrues nonclinical and clinical trial expenses based on work performed, which relies on estimates of total costs incurred based on patient enrollment, completion of studies, and other events. Costs incurred in purchasing technology assets and intellectual property are charged to research and development expense if the technology has not been conclusively proven to be feasible and has no alternative future use.
Preclinical and Clinical Trial Accruals	Preclinical and Clinical Trial Accruals The Company makes estimates of its accrued expenses as of each balance sheet date in the financial statements based on the facts and circumstances known at that time. Accrued expenses for preclinical studies and clinical trials are based on estimates of costs incurred and fees that may be associated with services provided by contract research organizations, or CROs, clinical trial investigational sites and other clinical trial-related activities. Payments under certain contracts with such parties depend on factors such as successful enrollment of patients, site initiation and the completion of clinical trial milestones. In accruing for these services, the Company estimates the time period over which services will be performed and the level of effort to be expended in each period. If possible, the Company obtains information regarding unbilled services directly from these service providers. However, the Company may be required to estimate these services based on other available information. If the Company underestimates or overestimates the activities or fees associated with a study or service at a given point in time, adjustments to research and development expenses may be necessary in future
Stock-Based Compensation	Stock-Based Compensation The Company accounts for stock-based compensation expense related to stock options, restricted stock units, or RSUs, performance-based RSUs, or PRSUs, and ESPP (as defined below) rights by estimating the fair value on the date of grant. The Company estimates the fair value of stock options granted to employees and non-employees using the Black-Scholes option pricing model. The fair value of RSUs and PRSUs granted to employees is estimated based on the closing price of the Company's common stock on the date of grant. The assumptions included in the Black-Scholes option pricing model includes (a) the risk-free interest rate, (b) the expected volatility of the Company's stock, (c) the expected term of the award, and (d) the expected dividend yield. For periods ending on or before December 31, 2020, the Company based its estimate of expected volatility on the historical volatility of a group of similar companies that are publically traded, due to the lack of an adequate history of a public market for the trading of the Company's common stock and a lack of adequate company-specific historical and implied volatility data. For these analyses, the Company selected companies with comparable characteristics, including enterprise value, risk profiles, and position within the industry, and with historical share price information sufficient to meet the expected life of the stock-based awards. The Company computed the expected volatility data using the daily close prices for the selected companies' shares during the equivalent period of the calculated expected term of the Company's stock-based awards. In January 2021 the Company began to compute the expected volatility data using the daily close prices for the Company's common stock during the equivalent period of the calculated expected term of the Company's stock-based awards. The Company estimated the expected life of employee stock options using the “simplified” method, whereby the expected life equals the average of the vesting term and the original contractual term of the option. The risk-free interest rates for periods within the expected life of the option are based on the yields of zero-coupon U.S. treasury securities. The expected dividend yield of zero reflects that the Company has not paid cash dividends since inception and do not intend to pay cash dividends in the foreseeable future. For awards subject to time-based vesting conditions, including those with a graded vesting schedule, stock-based compensation expense is recognized using the straight-line method. For performance-based awards to employees, (i) the fair value of the award is determined on the grant date, (ii) the Company assesses the probability of the individual performance milestones under the award being achieved and (iii) the fair value of the shares subject to the milestone is expensed over the implicit service period commencing once management believes the performance criteria is probable of being met. The Company recognizes forfeitures related to stock-based compensation as they occur and any compensation cost previously recognized for awards for which the requisite service has not been completed is reversed in the period that the award is forfeited.
Net Loss Per Share	Net Loss Per Share Basic net loss per share is calculated by dividing the net loss allocable to common shares by the weighted-average number of common shares outstanding for the period, without consideration for potentially dilutive securities. Diluted net loss per share is computed by dividing the net loss allocable to common shares by the weighted-average number of common shares and dilutive stock equivalents outstanding for the period determined using the treasury-stock and if-converted methods. Dilutive common stock equivalents are comprised of warrants, Series X Convertible Preferred Stock, RSUs, PRSUs and options outstanding under the Company’s stock option plans. For all periods presented, there is no difference in the number of shares used to calculate basic and diluted shares outstanding due to the Company's net loss position. Net loss allocable to common shares for the year ended December 31, 2020 includes non-cash deemed dividends of $2.8 million resulting from the recognition of a beneficial conversion feature. See Note 6 for additional information.
Fair Value of Financial Instruments	Fair Value of Financial Instruments The Company follows ASC 820-10 issued by the FASB with respect to fair value reporting for financial assets and liabilities. The guidance defines fair value, provides guidance for measuring fair value and requires certain disclosures. The guidance does not apply to measurements related to share-based payments. The guidance discusses valuation techniques such as the market approach (comparable market prices), the income approach (present value of future income or cash flow), and the cost approach (cost to replace the service capacity of an asset or replacement cost). The guidance establishes a fair value hierarchy that prioritizes the inputs to valuation techniques used to measure fair value into three broad levels. The Company’s financial instruments consist of cash and cash equivalents, restricted cash, accounts receivable, accounts payable, accrued liabilities, lease liability, and a term loan. Fair value estimates of these instruments are made at each reporting period end based on relevant market information. These estimates may be subjective in nature and involve uncertainties and matters of significant judgment and therefore cannot be determined with precision. The carrying amount of cash and cash equivalents, restricted cash, accounts receivable, accounts payable, and accrued liabilities are generally considered to be representative of their respective fair values because of the short-term nature of those instruments. The Company believes that the fair value of the term loan approximates its carrying value.
Recently Issued and Adopted Accounting Standards	Recently Issued Accounting Standards Recently Issued Accounting Standards Not Yet Adopted In August 2020, the FASB issued ASU 2020-06, "Accounting for Convertible Instruments and Contracts in an Entity's Own Equity," simplifies the accounting for certain convertible instruments by removing the separation models for convertible debt with a cash conversion feature or convertible instruments with a beneficial conversion feature. As a result, more convertible debt instruments will be reported as a single liability instrument with no separate accounting for embedded conversion features. Additionally, this ASU amends the diluted EPS calculation for convertible instruments by requiring the use of the if-converted method. The treasury stock method is no longer available. Entities may adopt this ASU using either a full or modified retrospective approach, and it is effective for interim and annual reporting periods beginning after December 15, 2021. Early adoption is permitted for interim and annual reporting periods beginning after December 15, 2020. The Company adopted ASU 2020-06 effective January 1, 2022. The adoption of this standard did not have a material impact on the Company's consolidated financial statements. Recently Adopted Accounting Standards In December 2019, the FASB issued ASU 2019-12, "Simplifying the Accounting for Income Taxes," which eliminates certain exceptions within ASC 740, Income Taxes, and clarifies other aspects of the current guidance to promote consistency among reporting entities. The Company adopted ASU 2019-12 effective January 1, 2021. The adoption of this standard did not have a material impact on the Company's consolidated financial statements.

SUMMARY OF SIGNIFICANT ACCOUN_3

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Tables)	12 Months Ended
	Dec. 31, 2021
Accounting Policies [Abstract]
Summary of Outstanding Potentially Dilutive Securities Excluded from Calculation of Diluted Net Loss Per Share	The following table sets forth the outstanding potentially dilutive securities that have been excluded in the calculation of diluted net loss per share because doing so would be anti-dilutive (in common stock equivalent shares): December 31, 2021 2020 2019 Common stock warrants 12,517,328 12,517,328 12,517,328 Series X Convertible Preferred stock 18,184,720 10,442,780 5,652,310 Common stock options, RSUs and PRSUs issued and outstanding 9,470,178 6,787,033 5,360,563 Total 40,172,226 29,747,141 23,530,201

FAIR VALUE MEASUREMENTS (Tables

FAIR VALUE MEASUREMENTS (Tables)	12 Months Ended
	Dec. 31, 2021
Fair Value Disclosures [Abstract]
Summary of Financial Instruments Measured at Fair Value on Recurring Basis	The following tables summarize the Company’s financial instruments measured at fair value on a recurring basis (in thousands): TOTAL LEVEL 1 LEVEL 2 LEVEL 3 December 31, 2021 Assets: Cash and money market accounts $ 59,680 $ 59,680 $ — $ — Restricted cash and money market accounts 2,593 2,593 — — Total assets at fair value $ 62,273 $ 62,273 $ — $ — December 31, 2020 Assets: Cash and money market accounts $ 35,912 $ 35,912 $ — $ — Restricted cash and money market accounts 7,037 7,037 — — Total assets at fair value $ 42,949 $ 42,949 $ — $ —

PROPERTY AND EQUIPMENT (Tables)

PROPERTY AND EQUIPMENT (Tables)	12 Months Ended
	Dec. 31, 2021
Property, Plant and Equipment [Abstract]
Schedule of Property and Equipment	Property and equipment consists of the following (in thousands): December 31, 2021 2020 Laboratory equipment $ 2,369 $ 2,304 Leasehold improvements 425 425 Computer hardware and software 425 404 Office equipment 119 119 Furniture and fixtures 142 142 3,480 3,394 Less accumulated depreciation and amortization (3,224) (3,052) Total $ 256 $ 342

DEBT (Tables)

DEBT (Tables)	12 Months Ended
	Dec. 31, 2021
Debt Disclosure [Abstract]
Schedule of Future Principal Payments Due	As of December 31, 2021, future principal payments due under the Loan Agreement, as amended, are as follows (in thousands): Year ended: December 31, 2022 $ 2,593 Total future principal payments due under the Loan Agreement $ 2,593

STOCKHOLDERS_ EQUITY (Tables)

STOCKHOLDERS’ EQUITY (Tables)	12 Months Ended
	Dec. 31, 2021
Equity [Abstract]
Schedule of Common Stock Reserved for Future Issuance	Common stock reserved for future issuance is as follows (in common stock equivalent shares): December 31, 2021 2020 Common stock warrants 12,517,328 12,517,328 Series X Convertible Preferred stock 18,184,720 10,442,780 Stock options, RSUs and PRSUs issued and outstanding 9,470,178 6,787,033 Authorized for future stock awards 2,436,984 2,813,131 Awards available under the ESPP 680,228 521,986 Total 43,289,438 33,082,258

EQUITY INCENTIVE PLANS (Tables)

EQUITY INCENTIVE PLANS (Tables)	12 Months Ended
	Dec. 31, 2021
Share-based Payment Arrangement [Abstract]
Summary of RSU and PRSU Activity	The following table summarizes RSU and PRSU activity during the year ended December 31, 2021: Number of Weighted Average Grant Date Fair Value Outstanding at December 31, 2020 428,235 $ 3.55 RSUs and PRSUs granted 932,875 2.27 RSUs and PRSUs vested (106,725) 3.40 RSUs and PRSUs canceled (80,298) 3.86 Outstanding at December 31, 2021 1,174,087 $ 2.53
Schedule of Stock Option Activity	The following table summarizes stock option activity during the year ended December 31, 2021: Number of Weighted Weighted Total Aggregate Outstanding at December 31, 2020 6,358,798 $ 3.59 7.04 $ 55 Options granted 2,981,200 2.38 Options exercised (2,930) 1.98 Options canceled (1,040,977) 3.19 Outstanding at December 31, 2021 8,296,091 $ 3.21 6.31 $ — Vested and expected to vest at December 31, 2021 8,296,091 $ 3.21 6.31 $ — Exercisable at December 31, 2021 5,377,439 $ 3.71 4.87 $ —
Summary of Black-Scholes Option Pricing Model Assumptions	The following table summarizes the Black-Scholes option pricing model assumptions used to estimate the fair value of stock options granted to employees under the 2015 EIP and 2020 IIP and the shares purchasable under the 2015 ESPP during the periods presented: For the years ended December 31, 2021 2020 2015 EIP and 2020 IIP Risk-free interest rate 0.61% - 1.35% 0.30% - 1.66% Expected dividend yield 0% 0% Expected volatility 67% - 70% 82% - 85% Expected term (years) 5.27 - 6.08 5.27 - 6.08 2015 ESPP Risk-free interest rate 0.02% - 0.63% 0.08% - 0.17% Expected dividend yield 0% 0% Expected volatility 58% - 79% 65% - 105% Expected term (years) 0.50 - 2.00 0.50 - 2.00
Summary of Stock-Based Compensation Expense	Stock-based compensation expense recognized for restricted shares, RSUs, PRSUs, stock options, and the ESPP has been reported in the statements of operations and comprehensive loss as follows (in thousands): Years ended December 31, 2021 2020 2019 Research and development $ 1,908 $ 2,089 $ 2,502 General and administrative 2,106 2,001 2,571 Total $ 4,014 $ 4,090 $ 5,073

SIGNIFICANT AGREEMENTS AND CO_2

SIGNIFICANT AGREEMENTS AND CONTRACTS (Tables)	12 Months Ended
	Dec. 31, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Summary of Collaborative Agreement Liabilities and Revenues Disaggregated by Timing of Revenue Recognition	The following table presents a summary of the activity in the Company's contract liabilities (recorded as deferred revenue on the balance sheet) during the year ended December 31, 2021 (in thousands): Opening balance, December 31, 2020 $ 25,010 Payments received 17,673 Payment receivable 781 Revenue from performance obligations satisfied during reporting period (11,131) Closing balance, December 31, 2021 $ 32,333 Current portion of deferred revenue $ 13,920 Long-term portion of deferred revenue 18,413 Total deferred revenue, December 31, 2021 $ 32,333 The following table presents our contract revenues disaggregated by timing of revenue recognition (in thousands): Years Ended December 31 2021 2020 2019 Point in Time Over Time Point in Time Over Time Point in Time Over Time Revenue from Mundipharma Collaboration Agreement: Licenses of Intellectual Property $ 813 $ — $ — $ — $ 17,861 $ — Research and Development Services — 12,069 — 10,513 — 2,670 Clinical Supply Services — 315 — 1,554 — 384 Total revenue from Mundipharma Collaboration Agreement $ 813 $ 12,384 $ — $ 12,067 $ 17,861 $ 3,054 Revenue from Janssen Collaboration Agreement: License of Intellectual Property $ 27,000 $ — $ — $ — $ — $ — Research and Development Services — 5,271 — — — — Clinical Supply Services — 4,104 — — — — Total revenue from Janssen Collaboration Agreement $ 27,000 $ 9,375 $ — $ — $ — $ —

INCOME TAXES (Tables)

INCOME TAXES (Tables)	12 Months Ended
	Dec. 31, 2021
Income Tax Disclosure [Abstract]
Reconciliation Between Federal Statutory and Provision For Income Taxes	The following table provides a reconciliation between income taxes computed at the federal statutory rate and the provision for income taxes (in thousands): Years Ended December 31, 2021 2020 2019 Federal income taxes at 21% for 2021, 2020 and 2019 $ (8,918) $ (15,142) $ (8,629) State income tax, net of federal benefit (1,426) (469) (1,899) Tax effect on nondeductible expenses 339 486 561 Research credits (2,487) (2,956) (4,141) Rate change (30) 344 (664) Change in valuation allowance 11,789 15,912 13,692 Reserve for uncertain tax positions 622 739 1,035 162m deferred tax asset limitation 76 857 — Other 35 229 45 Income tax expense $ — $ — $ —
Schedule of Components of Net Deferred Tax Assets	Significant components of the Company’s net deferred tax assets are as follows (in thousands): Years Ended December 31, 2021 2020 Deferred tax assets: Net operating losses $ 68,146 $ 62,238 Research credits 21,195 19,330 Intangibles 197 221 Stock compensation 2,478 2,007 Lease liability 595 224 Other 4,337 795 Total deferred tax assets 96,948 84,815 Less valuation allowance (96,397) (84,608) Deferred tax assets, net of valuation allowance 551 207 Deferred tax liabilities: Right-of-use assets (551) (207) Total deferred tax liabilities (551) (207) Net deferred tax assets $ — $ —
Schedule of Reconciliation Amount of Gross Unrecognized Tax Benefits	A reconciliation of the beginning and ending amount of gross unrecognized tax benefits for 2021, 2020 and 2019 is as follows (in thousands): Years Ended December 31, 2021 2020 2019 Balance as of the beginning of the year $ 23,335 $ 22,558 $ 16,524 Increases related to current year tax positions 655 777 1,074 Increases related to prior year tax positions — — 4,960 Balance as of the end of the year $ 23,990 $ 23,335 $ 22,558

COMMITMENTS AND CONTINGENCIES (

COMMITMENTS AND CONTINGENCIES (Tables)	12 Months Ended
	Dec. 31, 2021
Commitments and Contingencies Disclosure [Abstract]
Schedule of Amount, Timing and Uncertainty of Cash Flows from Operating Lease	The following table presents information about the amount, timing and uncertainty of cash flows arising from the Company's operating lease as of December 31, 2021 (in thousands): 2022 $ 1,359 2023 1,400 Total undiscounted operating lease payments 2,759 Less: Imputed interest (289) Present value of lease payments $ 2,470
Supplemental Balance Sheet Information	The balance sheet classification of the Company's operating lease is as follows (in thousands): Balance Sheet Classification: Operating lease right-of-use asset $ 2,287 Current portion of lease liability $ 1,148 Lease liability 1,322 Total operating lease liability $ 2,470

THE COMPANY AND BASIS OF PRES_2

THE COMPANY AND BASIS OF PRESENTATION (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2021USD ($)segment	Dec. 31, 2020USD ($)	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Accumulated deficit	$ 377,167	$ 334,700
Cash, cash equivalents and restricted cash	$ 62,273	$ 42,949	$ 60,268	$ 74,562
Number of operating segments | segment	1

SUMMARY OF SIGNIFICANT ACCOUN_4

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Additional Paid-In Capital
Property, Plant and Equipment [Line Items]
Dividends, preferred stock		$ 2.8
Minimum
Property, Plant and Equipment [Line Items]
Property and equipment estimated useful lives	3 years
Maximum
Property, Plant and Equipment [Line Items]
Property and equipment estimated useful lives	7 years

SUMMARY OF SIGNIFICANT ACCOUN_5

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Summary of Outstanding Potentially Dilutive Securities Excluded from Calculation of Diluted Net Loss Per Share (Details) - shares	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded in the calculation of diluted net loss per share (in shares)	40,172,226	29,747,141	23,530,201
Warrant
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded in the calculation of diluted net loss per share (in shares)	12,517,328	12,517,328	12,517,328
Series X Convertible Preferred stock
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded in the calculation of diluted net loss per share (in shares)	18,184,720	10,442,780	5,652,310
Common stock options, RSUs and PRSUs issued and outstanding
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded in the calculation of diluted net loss per share (in shares)	9,470,178	6,787,033	5,360,563

FAIR VALUE MEASUREMENTS - Summa

FAIR VALUE MEASUREMENTS - Summary of Financial Instruments Measured at Fair Value on Recurring Basis (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Assets:
Cash and money market accounts	$ 59,680	$ 35,912
Restricted cash and money market accounts	2,593	7,037
Assets at fair value	62,273	42,949
LEVEL 1
Assets:
Cash and money market accounts	59,680	35,912
Restricted cash and money market accounts	2,593	7,037
Assets at fair value	62,273	42,949
LEVEL 2
Assets:
Cash and money market accounts	0	0
Restricted cash and money market accounts	0	0
Assets at fair value	0	0
LEVEL 3
Assets:
Cash and money market accounts	0	0
Restricted cash and money market accounts	0	0
Assets at fair value	$ 0	$ 0

PROPERTY AND EQUIPMENT - Schedu

PROPERTY AND EQUIPMENT - Schedule of Property and Equipment (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 3,480	$ 3,394
Less accumulated depreciation and amortization	(3,224)	(3,052)
Total	256	342
Laboratory equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	2,369	2,304
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	425	425
Computer hardware and software
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	425	404
Office equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	119	119
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 142	$ 142

PROPERTY AND EQUIPMENT - Additi

PROPERTY AND EQUIPMENT - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Property, Plant and Equipment [Abstract]
Depreciation and amortization of property and equipment	$ 189	$ 286	$ 328

DEBT - Additional Information (

DEBT - Additional Information (Details) - USD ($)	Jul. 27, 2018	Oct. 03, 2016	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Shares of common stock issued upon exercise of warrant (in shares)		17,331
Warrants weighted average exercise price (USD per share)		$ 11.54
Percentage of principal of debt used to calculate number of shares issued by warrant		2.00%
Period of average closing price used to calculate number of shares issued by warrant		30 days
Warrant term		10 years
Restricted cash			$ 2,593,000	$ 7,037,000
Interest expense, debt			$ 12,000	$ 21,000	$ 36,000
Term Loan | Loan Agreement
Debt Instrument [Line Items]
Maximum borrowing capacity		$ 20,000,000
Prepayment fee percentage in year one		2.00%
Prepayment fee percentage in year two		1.00%
Stated interest rate	4.50%
Term Loan | Loan Agreement | Prime Rate
Debt Instrument [Line Items]
Basis spread on variable rate	0.75%
Term Loan | Term A Loan
Debt Instrument [Line Items]
Debt face amount		$ 10,000,000
Stated interest rate			4.50%
Term Loan | Term B Loan
Debt Instrument [Line Items]
Maximum borrowing capacity		$ 10,000,000

DEBT - Schedule of Future Princ

DEBT - Schedule of Future Principal Payments Due (Details) - Term Loan - Term A Loan $ in Thousands	Dec. 31, 2021USD ($)
Year ended:
December 31, 2022	$ 2,593
Total future principal payments due under the Loan Agreement	$ 2,593

STOCKHOLDERS_ EQUITY - Addition

STOCKHOLDERS’ EQUITY - Additional Information (Details)	Oct. 13, 2021USD ($)$ / sharesshares	Aug. 12, 2020shares	Feb. 12, 2020USD ($)$ / sharesshares	Jan. 22, 2020USD ($)	Sep. 03, 2019USD ($)day$ / sharesshares	Mar. 22, 2019shares	May 31, 2018$ / sharesshares	Dec. 31, 2021USD ($)vote$ / sharesshares	Dec. 31, 2020USD ($)$ / sharesshares	Dec. 31, 2019shares	Oct. 03, 2016$ / shares
Class of Stock [Line Items]
Offering price (USD per share) | $ / shares	$ 15.50
Consideration received per transaction | $	$ 36,600,000
Preferred stock, shares authorized (in shares)								10,000,000	10,000,000
Preferred stock, par value (USD per share) | $ / shares								$ 0.0001	$ 0.0001
Common stock, shares authorized (in shares)								200,000,000	200,000,000
Number of votes for each share held | vote								1
Dividends in arrears or default | $								$ 0
Warrants exercise price (USD per share) | $ / shares											$ 11.54
Rights Offering, January 2020
Class of Stock [Line Items]
Proceeds from sale of equity | $			$ 29,200,000
Net proceeds | $			30,000,000	$ 30,000,000
Preferred units, offering costs | $			$ 800,000
Controlled Equity Sales Agreement, Cantor Fitzgerald and Company
Class of Stock [Line Items]
Shares sold (in shares)								5,523,429	3,515,871
Net proceeds | $								$ 12,300,000	$ 11,200,000
Sale of stock, consideration remaining on transaction | $								$ 48,500,000
Series X Convertible Preferred Stock
Class of Stock [Line Items]
Preferred stock, shares issued (in shares)	774,194							1,870,713	1,096,519
Proceeds from sale of equity | $	$ 38,500,000
Preferred stock, shares authorized (in shares)							5,000,000	4,947,759	4,947,759
Preferred stock, par value (USD per share) | $ / shares							$ 0.0001	$ 0.0001	$ 0.0001
Conversion of stock, shares issued (in shares)						120,000
Issuance of series X convertible preferred stock in exchange for common stock (in shares)		52,241
Common stock issued for each preferred stock (in shares)							10
Maximum ownership following conversion							9.99%
Series X Convertible Preferred Stock | Rights Offering, January 2020
Class of Stock [Line Items]
Shares sold (in shares)			531,288
Offering price (USD per share) | $ / shares			$ 25.10
Dividends, preferred stock | $			$ 2,800,000
Common Stock
Class of Stock [Line Items]
Conversion of stock, shares converted (in shares)						1,200,000
Common Stock | Rights Offering, January 2020
Class of Stock [Line Items]
Shares sold (in shares)			6,639,307
Offering price (USD per share) | $ / shares			$ 2.51
Common Stock | Stock Purchase Agreement
Class of Stock [Line Items]
Shares sold (in shares)					4,781,408
Offering price (USD per share) | $ / shares					$ 1.884
Net proceeds | $					$ 9,000,000
Premium percentage on volume weighted average price per share					20.00%
Threshold trading days | day					10
Common Stock
Class of Stock [Line Items]
Offering price (USD per share) | $ / shares	$ 1.55
Issuance of series X convertible preferred stock in exchange for common stock (in shares)		522,410							522,410	1,200,000
Common Stock | Public Stock Offering
Class of Stock [Line Items]
Shares sold (in shares)	17,064,511
Common Stock | Over-Allotment Option
Class of Stock [Line Items]
Shares sold (in shares)	2,225,805
Common Stock Warrant
Class of Stock [Line Items]
Outstanding warrants to purchase common stock (in shares)								12,517,328	12,517,328
Outstanding warrants to purchase common stock, intrinsic value | $								$ 0	$ 0
Common Stock Warrant | Weighted Average
Class of Stock [Line Items]
Warrants exercise price (USD per share) | $ / shares								$ 6.82	$ 6.82

STOCKHOLDERS_ EQUITY - Schedule

STOCKHOLDERS’ EQUITY - Schedule of Common Stock Reserved for Future Issuance (Details) - shares	Dec. 31, 2021	Dec. 31, 2020
Class of Stock [Line Items]
Total (in shares)	43,289,438	33,082,258
Warrant
Class of Stock [Line Items]
Total (in shares)	12,517,328	12,517,328
Series X Convertible Preferred Stock
Class of Stock [Line Items]
Total (in shares)	18,184,720	10,442,780
Stock options, RSUs and PRSUs issued and outstanding
Class of Stock [Line Items]
Total (in shares)	9,470,178	6,787,033
Authorized for future stock awards
Class of Stock [Line Items]
Total (in shares)	2,436,984	2,813,131
Awards available under the ESPP
Class of Stock [Line Items]
Total (in shares)	680,228	521,986

EQUITY INCENTIVE PLANS - Additi

EQUITY INCENTIVE PLANS - Additional Information (Details) $ / shares in Units, $ in Millions	Dec. 18, 2019USD ($)$ / sharesshares	Nov. 20, 2019$ / shares	Mar. 31, 2015shares	Dec. 31, 2021USD ($)$ / sharesshares	Dec. 31, 2020USD ($)$ / sharesshares	Dec. 31, 2019USD ($)$ / sharesshares	Mar. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Eligible common stock for purchase in the option exchange, exercise price minimum (USD per share) | $ / shares		$ 2.28
Eligible common stock for purchase in the option exchange (in shares) | shares	1,656,379
Percentage of eligible common stock for purchase in the option exchange	60.40%
New option to purchase common stock in the option exchange (in shares) | shares	1,529,814
New option to purchase common stock, exercise price, in the option exchange (USD per share) | $ / shares	$ 2.45
Incremental compensation expense in the option exchange	$ 0.7
Weighted average grant date fair values of stock options granted (USD per share) | $ / shares				$ 1.42	$ 1.48	$ 1.78
Unrecognized share-based compensation expense of unvested employee stock options				$ 3.7
Unvested stock options, unrecognized cost expected to be recognized				2 years 3 months 18 days
RSUs and PRSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in dollars per share) | $ / shares				$ 2.27	$ 2.29	$ 2.88
Vested in period, fair value				$ 0.4	$ 0.3	$ 0.5
Unrecognized share-based compensation expense of unvested employee stock options				$ 2.3
Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expiration period		7 years
Minimum | Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period		1 year
Maximum | Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period		3 years
2015 EIP and 2020 IIP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Automatic annual increase in shares authorized for issuance in equity incentive plan			4.00%
Expiration period			10 years
Price of stock option as percentage of estimated fair value of shares on date of grant			100.00%
Employee voting power, percentage (more than)			10.00%
2015 EIP and 2020 IIP | More than 10% of voting power
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Price of stock option as percentage of estimated fair value of shares on date of grant			110.00%
2015 EIP and 2020 IIP | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period			3 years
2015 EIP and 2020 IIP | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period			4 years
2015 Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Automatic annual increase in shares authorized for issuance in equity incentive plan			1.00%
Price of stock option as percentage of estimated fair value of shares on date of grant			85.00%
Employee payroll deduction under the stock plan							15.00%
Issuance of common stock under employee stock purchase plan (in shares) | shares				289,671	280,139	242,501
Unrecognized share-based compensation expense of unvested employee stock options				$ 0.6
Unvested stock options, unrecognized cost expected to be recognized				8 months 12 days
2015 Employee Stock Purchase Plan | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock shares outstanding (in shares) | shares			490,336
Non Section 16 Officer, Employee
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Option exchange, exchange ratio		1
Section 16 Officer
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Option exchange, exchange ratio		1.5

EQUITY INCENTIVE PLANS - Summar

EQUITY INCENTIVE PLANS - Summary of RSU and PRSU Activity (Details) - RSUs and PRSUs - $ / shares	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Number of RSUs and PRSUs
Outstanding, beginning of period (in shares)	428,235
Granted (in shares)	932,875
Vested (in shares)	(106,725)
Canceled (in shares)	(80,298)
Outstanding, end of period (in shares)	1,174,087	428,235
Weighted Average Grant Date Fair Value
Outstanding, beginning of period (in dollars per share)	$ 3.55
Granted (in dollars per share)	2.27	$ 2.29	$ 2.88
Vested (in dollars per share)	3.40
Granted (in dollars per share)	3.86
Outstanding, end of period (in dollars per share)	$ 2.53	$ 3.55

EQUITY INCENTIVE PLANS - Summ_2

EQUITY INCENTIVE PLANS - Summary of Stock Option Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Number of Shares
Beginning balance (in shares)	6,358,798
Granted (in shares)	2,981,200
Exercised (in shares)	(2,930)
Canceled (in shares)	(1,040,977)
Ending balance (in shares)	8,296,091	6,358,798
Vested and expected to vest (in shares)	8,296,091
Exercisable (in shares)	5,377,439
Weighted Average Exercise Price
Beginning balance (USD per share)	$ 3.59
Granted (USD per share)	2.38
Exercised (USD per share)	1.98
Canceled (USD per share)	3.19
Ending balance (USD per share)	3.21	$ 3.59
Vested and expected to vest (USD per share)	3.21
Exercisable (USD per share)	$ 3.71
Weighted Average Remaining Contractual Life in Years
Weighted average remaining contractual term	6 years 3 months 21 days	7 years 14 days
Weighted average remaining contractual term, vested and expected to vest	6 years 3 months 21 days
Weighted average remaining contractual term, exercisable	4 years 10 months 13 days
Total Aggregate Intrinsic Value (in thousands)
Aggregate intrinsic value, beginning balance	$ 55
Aggregate intrinsic value, ending balance	0	$ 55
Aggregate intrinsic value, vested and expected to vest	0
Aggregate intrinsic value, exercisable	$ 0

EQUITY INCENTIVE PLANS - Summ_3

EQUITY INCENTIVE PLANS - Summary of Black-Scholes Option Pricing Model Assumptions (Details)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
2015 EIP and 2020 IIP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rate, minimum	0.61%	0.30%
Risk-free interest rate, maximum	1.35%	1.66%
Expected dividend yield	0.00%	0.00%
Expected volatility, minimum	67.00%	82.00%
Expected volatility, maximum	70.00%	85.00%
2015 EIP and 2020 IIP | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (in years)	5 years 3 months 7 days	5 years 3 months 7 days
2015 EIP and 2020 IIP | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (in years)	6 years 29 days	6 years 29 days
2015 Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rate, minimum	0.02%	0.08%
Risk-free interest rate, maximum	0.63%	0.17%
Expected dividend yield	0.00%	0.00%
Expected volatility, minimum	58.00%	65.00%
Expected volatility, maximum	79.00%	105.00%
2015 Employee Stock Purchase Plan | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (in years)	6 months	6 months
2015 Employee Stock Purchase Plan | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (in years)	2 years	2 years

EQUITY INCENTIVE PLANS - Summ_4

EQUITY INCENTIVE PLANS - Summary of Stock-Based Compensation Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 4,014	$ 4,090	$ 5,073
Research and development
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	1,908	2,089	2,502
General and administrative
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 2,106	$ 2,001	$ 2,571

SIGNIFICANT AGREEMENTS AND CO_3

SIGNIFICANT AGREEMENTS AND CONTRACTS - Additional Information (Details) - USD ($)	Mar. 31, 2021	Sep. 03, 2019	May 31, 2021	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Nov. 30, 2020	Sep. 30, 2019
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Long-term deferred revenue				$ 18,413,000	$ 11,145,000
Revenue from collaborative agreement				49,572,000	12,067,000	$ 20,915,000
Mundipharma Medical Company
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Collaborative agreement, maximum cost share, percentage		50.00%
Affiliated Entity | Mundipharma Medical Company
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Collaborative agreement, maximum cost share		$ 31,200,000
Collaborative agreement, potential transaction value		568,400,000
Payments related to collaborative agreement		30,000,000
Revenue recognized from collaborative agreement related to performance obligation satisfied at a point in time				813,000	0	17,861,000
Payment receivable				2,800,000	11,100,000
Affiliated Entity | Mundipharma Medical Company | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-01-01
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Revenue, remaining performance obligation, amount				$ 17,900,000
Revenue, remaining performance obligation, expected timing of satisfaction, period				2 years
Affiliated Entity | Mundipharma Medical Company | Licenses of Intellectual Property
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Revenue recognized from collaborative agreement related to performance obligation satisfied at a point in time				$ 813,000	0	17,861,000		$ 17,900,000
Long-term deferred revenue				2,800,000			$ 11,100,000
Affiliated Entity | Mundipharma Medical Company | Milestone Achievement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Long-term deferred revenue				800,000
Revenue from collaborative agreement				2,000,000	0	0
Affiliated Entity | Mundipharma Medical Company | Royalty
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Revenue from collaborative agreement				0	0	0
Affiliated Entity | Janssen Pharmaceuticals, Inc.
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Collaborative agreement, maximum cost share	$ 60,600,000
Collaborative arrangement, termination provisions, required period of written notice	90 days
Collaborative arrangement, election to proceed notice, period post delivery of results	90 days
Payments related to collaborative agreement	$ 27,000,000
Revenue recognized from collaborative agreement related to performance obligation satisfied at a point in time				27,000,000	0	0
Payment receivable				2,400,000
Affiliated Entity | Janssen Pharmaceuticals, Inc. | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-01-01
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Revenue, remaining performance obligation, amount				51,300,000
Affiliated Entity | Janssen Pharmaceuticals, Inc. | Development, Regulatory, And Commercial Milestones
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Collaborative agreement, potential transaction value	695,000,000
Affiliated Entity | Janssen Pharmaceuticals, Inc. | R&D Funding
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Collaborative agreement, potential transaction value	58,200,000
Affiliated Entity | Janssen Pharmaceuticals, Inc. | Upfront Payment
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Payments related to collaborative agreement	$ 27,000,000
Affiliated Entity | Janssen Pharmaceuticals, Inc. | Licenses of Intellectual Property
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Revenue recognized from collaborative agreement related to performance obligation satisfied at a point in time				27,000,000	$ 0	$ 0
Revenue from collaborative agreement			$ 27,000,000
Affiliated Entity | Janssen Pharmaceuticals, Inc. | Milestone Achievement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Revenue from collaborative agreement				0
Affiliated Entity | Janssen Pharmaceuticals, Inc. | Royalty
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Revenue from collaborative agreement				$ 0
Affiliated Entity | Near Term Milestone | Mundipharma Medical Company
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Collaborative arrangement, additional third party funding commitment		$ 11,100,000

SIGNIFICANT AGREEMENTS AND CO_4

SIGNIFICANT AGREEMENTS AND CONTRACTS - Summary of Contract Liability Activity (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Revenue From Collaborative Arrangement, Excluding Revenue From Contract With Customer, Liability [Roll Forward]
Closing balance	$ 32,333
Current deferred revenue	13,920	$ 13,865
Long-term deferred revenue	18,413	11,145
Total deferred revenue, December 31, 2021	32,333
Affiliated Entity | Mundipharma Medical Company
Revenue From Collaborative Arrangement, Excluding Revenue From Contract With Customer, Liability [Roll Forward]
Opening balance	25,010
Payments received	17,673
Payment receivable	781
Revenue from performance obligations satisfied during reporting period	(11,131)
Closing balance	32,333
Total deferred revenue, December 31, 2021	$ 32,333	$ 25,010

SIGNIFICANT AGREEMENTS AND CO_5

SIGNIFICANT AGREEMENTS AND CONTRACTS - Revenues Disaggregated by Timing of Revenue Recognition (Details) - Affiliated Entity - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Sep. 30, 2019
Mundipharma Medical Company
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Point in Time	$ 813	$ 0	$ 17,861
Over Time	12,384	12,067	3,054
Mundipharma Medical Company | Licenses of Intellectual Property
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Point in Time	813	0	17,861	$ 17,900
Over Time	0	0	0
Mundipharma Medical Company | Research and Development Services
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Point in Time	0	0	0
Over Time	12,069	10,513	2,670
Mundipharma Medical Company | Clinical Supply Services
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Point in Time	0	0	0
Over Time	315	1,554	384
Janssen Pharmaceuticals, Inc.
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Point in Time	27,000	0	0
Over Time	9,375	0	0
Janssen Pharmaceuticals, Inc. | Licenses of Intellectual Property
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Point in Time	27,000	0	0
Over Time	0	0	0
Janssen Pharmaceuticals, Inc. | Research and Development Services
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Point in Time	0	0	0
Over Time	5,271	0	0
Janssen Pharmaceuticals, Inc. | Clinical Supply Services
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Point in Time	0	0	0
Over Time	$ 4,104	$ 0	$ 0

INCOME TAXES - Reconciliation B

INCOME TAXES - Reconciliation Between Income Taxes Computed at Federal Statutory Rate and Provision for Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Federal income taxes at 21% for 2021, 2020 and 2019	$ (8,918)	$ (15,142)	$ (8,629)
State income tax, net of federal benefit	(1,426)	(469)	(1,899)
Tax effect on nondeductible expenses	339	486	561
Research credits	(2,487)	(2,956)	(4,141)
Rate change	(30)	344	(664)
Change in valuation allowance	11,789	15,912	13,692
Reserve for uncertain tax positions	622	739	1,035
162m deferred tax asset limitation	76	857	0
Other	35	229	45
Income tax expense	$ 0	$ 0	$ 0
Federal statutory income tax rate, percent	21.00%	21.00%	21.00%

INCOME TAXES - Significant Comp

INCOME TAXES - Significant Components of Net Deferred Tax Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Deferred tax assets:
Net operating losses	$ 68,146	$ 62,238
Research credits	21,195	19,330
Intangibles	197	221
Stock compensation	2,478	2,007
Lease liability	595	224
Other	4,337	795
Total deferred tax assets	96,948	84,815
Less valuation allowance	(96,397)	(84,608)
Deferred tax assets, net of valuation allowance	551	207
Deferred tax liabilities:
Right-of-use assets	(551)	(207)
Total deferred tax liabilities	(551)	(207)
Net deferred tax assets	$ 0	$ 0

INCOME TAXES - Additional Infor

INCOME TAXES - Additional Information (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Tax Contingency [Line Items]
Research and development credit carryforwards, no subject to expiration	$ 4,400
Deferred tax assets, valuation allowance	96,397	$ 84,608
Unrecognized tax benefits	23,990	$ 23,335	$ 22,558	$ 16,524
Unrecognized tax benefits that would impact on effective tax rate	19,700
Federal
Income Tax Contingency [Line Items]
Net operating loss carryforwards	306,800
Tax credit carryforwards, research and development	24,900
State
Income Tax Contingency [Line Items]
Net operating loss carryforwards	234,200
Tax credit carryforwards, research and development	$ 4,400

INCOME TAXES - Reconciliation o

INCOME TAXES - Reconciliation of Beginning and Ending Amount of Gross Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Unrecognized tax benefits
Balance as of the beginning of the year	$ 23,335	$ 22,558	$ 16,524
Increases related to current year tax positions	655	777	1,074
Increases related to prior year tax positions	0	0	4,960
Balance as of the end of the year	$ 23,990	$ 23,335	$ 22,558

COMMITMENTS AND CONTINGENCIES -

COMMITMENTS AND CONTINGENCIES - Additional Information (Details)	Jul. 14, 2021USD ($)	Dec. 31, 2021USD ($)claimextension	Dec. 31, 2020USD ($)	Dec. 31, 2019USD ($)
Commitments and Contingencies Disclosure [Abstract]
Number of claims and actions pending | claim		0
Operating leases renewal term	24 months
Base rent	$ 103,733
Lessee, operating lease, annual rate increase	3.00%
Number of operating lease options for extension | extension		2
Term of extension		2 years
Adjusted incremental borrowing rate used in measuring lease liability		10.80%
Weighted average remaining lease term		2 years
Present value of lease payments		$ 2,470,000
Operating lease, payments		1,000,000
Lease rent expense		$ 1,200,000	$ 1,000,000	$ 1,000,000

COMMITMENTS AND CONTINGENCIES_2

COMMITMENTS AND CONTINGENCIES - Schedule of Amount, Timing and Uncertainty of Cash Flows from Operating Lease (Details) $ in Thousands	Dec. 31, 2021USD ($)
Commitments and Contingencies Disclosure [Abstract]
2022	$ 1,359
2023	1,400
Total undiscounted operating lease payments	2,759
Less: Imputed interest	(289)
Present value of lease payments	$ 2,470

COMMITMENTS AND CONTINGENCIES_3

COMMITMENTS AND CONTINGENCIES - Supplemental Balance Sheet Information (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Commitments and Contingencies Disclosure [Abstract]
Operating lease right-of-use asset	$ 2,287	$ 868
Current portion of lease liability	1,148	939
Lease liability	1,322	$ 0
Total operating lease liability	$ 2,470