Equillium (EQ) 10-K 24 Mar 21 2020 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2020	Mar. 19, 2021	Jun. 30, 2020
Cover [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2020
Document Fiscal Year Focus	2020
Entity Current Reporting Status	Yes
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Document Fiscal Period Focus	FY
Trading Symbol	EQ
Entity Registrant Name	EQUILLIUM, INC.
Entity Central Index Key	0001746466
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
ICFR Auditor Attestation Flag	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		29,040,270
Entity Public Float			$ 18,800,000
Title of 12(b) Security	Common Stock, par value $0.0001 per share
Entity File Number	001-38692
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	82-1554746
Entity Interactive Data Current	Yes
Security Exchange Name	NASDAQ
Entity Address, Address Line One	2223 Avenida de la Playa
Entity Address, Address Line Two	Suite 105
Entity Address, City or Town	La Jolla
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	92037
City Area Code	858
Local Phone Number	412-5302
Document Annual Report	true
Document Transition Report	false
Documents Incorporated by Reference	DOCUMENTS INCORPORATED BY REFERENCE Part III of this Annual Report on Form 10-K incorporates by reference certain information from the registrant’s definitive Proxy Statement for its 2021 annual meeting of shareholders, which the registrant intends to file pursuant to Regulation 14A with the Securities and Exchange Commission not later than 120 days after the registrant’s fiscal year end of December 31, 2020. Except with respect to information specifically incorporated by reference in this Form 10-K, the Proxy Statement is not deemed to be filed as part of this Form 10-K.

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 23,982	$ 13,219
Short-term investments	58,181	39,924
Prepaid expenses and other current assets	3,011	2,288
Total current assets	85,174	55,431
Property and equipment, net	239	93
Other assets	15	15
Total assets	85,428	55,539
Current liabilities:
Accounts payable	2,766	1,873
Accrued expenses	2,813	2,010
Current portion of long-term notes payable	1,666
Total current liabilities	7,245	3,883
Long-term notes payable	8,275	9,681
Other non-current liabilities	54	127
Total liabilities	15,574	13,691
Commitments and contingencies
Stockholders' equity:
Common stock, $0.0001 par value; 200,000,000 shares authorized as of December 31, 2020 and 2019; 24,753,102 and 17,425,654 shares issued and outstanding as of December 31, 2020 and 2019, respectively	2	1
Additional paid-in capital	141,074	82,938
Accumulated other comprehensive (loss) income	(297)	21
Accumulated deficit	(70,925)	(41,112)
Total stockholders' equity	69,854	41,848
Total liabilities and stockholders' equity	$ 85,428	$ 55,539

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2020	Dec. 31, 2019
Statement Of Financial Position [Abstract]
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares authorized	200,000,000	200,000,000
Common stock, shares issued	24,753,102	17,425,654
Common stock, shares outstanding	24,753,102	17,425,654

Consolidated Statements of Oper

Consolidated Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Operating expenses:
Research and development	$ 19,384	$ 17,640
General and administrative	10,164	9,087
Total operating expenses	29,548	26,727
Loss from operations	(29,548)	(26,727)
Other (expense) income, net:
Interest expense	(1,099)	(279)
Interest income	476	1,391
Other income, net	358	15
Total other (expense) income, net	(265)	1,127
Net loss	(29,813)	(25,600)
Other comprehensive (loss) income, net:
Unrealized (loss) gain on available-for-sale securities, net	(41)	44
Foreign currency translation loss	(277)	(28)
Total other comprehensive (loss) income, net	(318)	16
Comprehensive loss	$ (30,131)	$ (25,584)
Net loss per share, basic and diluted	$ (1.46)	$ (1.47)
Weighted-average number of common shares outstanding, basic and diluted	20,355,534	17,378,096

Consolidated Statements of Stoc

Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	ATM	Common Stock	Common StockATM	Additional Paid-in Capital	Additional Paid-in CapitalATM	Accumulated Other Comprehensive (Loss) Income	Accumulated Deficit
Balance at Dec. 31, 2018	$ 64,935		$ 1		$ 80,441		$ 5	$ (15,512)
Balance, Shares at Dec. 31, 2018			17,376,236
Issuance of common stock		$ (206)				$ (206)
Issuance of common stock, Shares				18,250
Issuance of common stock under or pursuant to employee stock purchase plan	42				42
Issuance of common stock pursuant to employee stock purchase plan, Shares			13,321
Vesting of restricted stock liability	74				74
Issuance of common stock warrants	266				266
Exercise of stock options	69				69
Exercise of stock options, Shares			17,847
Stock-based compensation expense	2,252				2,252
Comprehensive income (loss)	16						16
Net loss	(25,600)							(25,600)
Balance at Dec. 31, 2019	41,848		$ 1		82,938		21	(41,112)
Balance, Share at Dec. 31, 2019			17,425,654
Issuance of common stock from follow-on offering, net of issuance costs	35,717		$ 1		35,716
Issuance of common stock from follow-on offering, net of issuance costs, Shares			5,461,169
Issuance of common stock	252	$ 18,115			252	$ 18,115
Issuance of common stock, Shares			83,662	1,714,174
Issuance of common stock under or pursuant to employee stock purchase plan	156				156
Issuance of common stock pursuant to employee stock purchase plan, Shares			65,443
Vesting of restricted stock liability	73				73
Exercise of stock options	7				7
Exercise of stock options, Shares			3,000
Stock-based compensation expense	3,817				3,817
Comprehensive income (loss)	(318)						(318)
Net loss	(29,813)							(29,813)
Balance at Dec. 31, 2020	$ 69,854		$ 2		$ 141,074		$ (297)	$ (70,925)
Balance, Share at Dec. 31, 2020			24,753,102

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Operating activities:
Net loss	$ (29,813,000)	$ (25,600,000)
Adjustments to reconcile net loss to cash used in operating activities:
Depreciation and amortization	45,000	23,000
Stock-based compensation	3,817,000	2,252,000
Net unrealized gain on foreign currency transactions	(360,000)	(20,000)
Non-cash consulting expense	81,000
Amortization of term loan discount and issuance costs	260,000	65,000
Realized gain on investments	(13,000)
Amortization/accretion of investments, net	104,000	(382,000)
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	(491,000)	(1,115,000)
Accounts payable	894,000	775,000
Accrued expenses	852,000	1,053,000
Net cash used in operating activities	(24,624,000)	(22,949,000)
Investing activities:
Purchases of property and equipment	(202,000)	(74,000)
Purchases of short-term investments	(55,510,000)	(54,619,000)
Maturities of short-term investments	37,120,000	52,527,000
Net cash used in investing activities	(18,592,000)	(2,166,000)
Financing activities:
Proceeds from issuance of notes payable, net of issuance costs		9,881,000
Proceeds from ESPP purchases	156,000	42,000
Proceeds from exercise of stock options	7,000	69,000
Net cash provided by financing activities	53,945,000	9,836,000
Effect of exchange rate changes on cash and cash equivalents	34,000	(10,000)
Net increase (decrease) in cash and cash equivalents	10,763,000	(15,289,000)
Cash and cash equivalents at beginning of period	13,219,000	28,508,000
Cash and cash equivalents at end of period	23,982,000	13,219,000
Supplemental cash flow information:
Cash paid for interest	839,000	142,000
Fair value of common stock warrants in connection with issuance of notes payable		266,000
ATM issuance costs in accrued expenses		50,000
Amounts included in accounts payable for purchases of property and equipment		11,000
Follow-on Offering
Financing activities:
Proceeds from issuance of common stock, net of issuance costs	35,717,000
ATM Facility
Financing activities:
Proceeds from issuance of common stock, net of issuance costs	18,065,000	$ (156,000)
Lincoln Park Capital Fund, LLC
Supplemental cash flow information:
Issuance of commitment shares to Lincoln Park pursuant to agreement	$ 171,000

Organization and Accounting Pro

Organization and Accounting Pronouncements	12 Months Ended
	Dec. 31, 2020
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Organization and Accounting Pronouncements	1. Organization and Accounting Pronouncements Description of Business Equillium, Inc. (the Company) was incorporated in the state of Delaware on March 16, 2017. The Company is a clinical-stage biotechnology company leveraging deep understanding of immunology to develop novel products to treat severe autoimmune and inflammatory disorders with high unmet medical need. From inception through December 31, 2020, the Company has devoted substantially all of its efforts to organizing and staffing the Company, business planning, raising capital, in-licensing rights to itolizumab (EQ001), conducting preclinical research, filing three initial Investigational New Drug applications (INDs), conducting clinical development of the Company’s initial product candidate, itolizumab (EQ001), conducting business development activities, and the general and administrative activities associated with operating as a public company. In addition, the Company has a limited operating history, has not generated revenues from its principal operations, and the sales and income potential of its business is unproven. Liquidity and Business Risks As of December 31, 2020, the Company had $82.2 million in cash, cash equivalents and short-term investments. The Company has incurred significant operating losses and negative cash flows from operations. The Company The COVID-19 outbreak in the United States and the rest of the world has caused disruptions to the Company’s business, which may delay results of the Company’s clinical trials and adversely impact the Company’s business. The Company cannot predict how legal and regulatory responses to concerns about COVID-19 or other major public health issues will impact the Company’s business, nor can it predict potential adverse impacts related to the availability of capital to fund the Company’s operations. Additionally, the Company’s workforce and outside consultants may also be affected, which could result in an adverse impact on the Company’s ability to conduct business. Any of these factors, alone or in combination with others, could harm the Company’s business, results of operations, financial condition or liquidity. However, the magnitude, timing, and duration of any such potential financial impacts cannot be reasonably estimated at this time. Basis of Presentation The accompanying consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles (GAAP) and the rules and regulations of the SEC. Any reference in these notes to applicable guidance is meant to refer to GAAP as found in the Accounting Standards Codification (ASC) and Accounting Standards Updates (ASU) promulgated by the Financial Accounting Standards Board (FASB). Principles of Consolidation In January 2019, the Company created a wholly-owned subsidiary in Australia with the Company serving as the sole shareholder through the subscription of shares. The accompanying consolidated financial statements include the accounts of the Company and its wholly-owned subsidiary. All intercompany transactions and balances have been eliminated in consolidation. Foreign Currency Translation The Company’s wholly-owned subsidiary in Australia uses its local currency as its functional currency. Assets and liabilities are translated into U.S. dollars at quarter-end exchange rates and revenues and expenses are translated at average exchange rates during the year-to-date periods. Foreign currency translation adjustments for the reported periods are included in accumulated other comprehensive loss in the Company’s consolidated statements of comprehensive loss, and the cumulative effect is included in the stockholders’ equity section of the Company’s consolidated balance sheets. Realized and unrealized gains and losses denominated in foreign currencies are recorded in operating expenses in the Company’s consolidated statements of operations. For the years ended December 31, 2020 and 2019, net realized and unrealized gains totaled $0.3 million and $15,000, respectively. Recent Accounting Pronouncements In February 2016, the FASB issued ASU 2016-02, Leases (Topic 842) Financial Instruments—Credit Losses (Topic 326) Derivatives and Hedging (Topic 815) Leases (Topic 842 Effective Dates (ASU 2019-10), In June 2016, the FASB issued ASU No. 2016-13, Measurement of Credit Losses on Financial Instruments . In December 2019, the FASB issued ASU No. 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes Adopted Accounting Pronouncements In August 2018, the FASB issued ASU 2018-13, Fair Value Measurement (Topic 820) – Disclosure Framework – Changes to the Disclosure Requirements for Fair Value Measurement

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2020
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies Use of Estimates The preparation of the Company’s consolidated financial statements requires the Company to make estimates and assumptions that impact the reported amounts of assets, liabilities and expenses and the disclosure of contingent assets and liabilities in the consolidated financial statements and accompanying notes. Significant estimates in the Company’s consolidated financial statements relate to clinical trial accruals and the valuation of equity awards. Management evaluates its estimates on an ongoing basis. Although estimates are based on the Company’s historical experience, knowledge of current events, and actions it may undertake in the future, actual results may ultimately materially differ from these estimates and assumptions. Concentration of Credit Risk and Off-Balance Sheet Risk Financial instruments which potentially subject the Company to significant concentration of credit risk consist of cash and cash equivalents and short-term investments. The Company maintains deposits in federally insured financial institutions in excess of federally insured limits. The Company has not experienced any losses in such accounts, and management believes that the Company is not exposed to significant credit risk due to the financial position of the depository institutions in which those deposits are held. The Company’s investment policy includes guidelines for the quality of the related institutions and financial instruments and defines allowable investments that the Company may invest in, which the Company believes minimizes the exposure to concentration of credit risk. Comprehensive Loss The Company is required to report all components of comprehensive loss, including net loss, in the consolidated financial statements in the period in which they are recognized. Comprehensive loss is defined as the change in equity during a period from transactions and other events and circumstances from non-owner sources, including unrealized gains and losses on investments and foreign currency gains and losses. Other comprehensive (loss) income, net includes unrealized losses or gains on short-term investments as well as foreign currency translation losses or gains. Cash and Cash Equivalents Cash and cash equivalents include cash in readily available checking and savings accounts, and money market funds. The Company considers all highly liquid investments with an original maturity of three months or less from the date of purchase to be cash equivalents. Short-Term Investments Available-for-sale securities are carried at fair value, with the unrealized gains and losses reported in comprehensive loss . The amortized cost of available-for-sale debt securities is adjusted for amortization of premiums and accretion of discounts to maturity. Such amortization and accretion are included in interest income. Realized gains and losses and declines in value judged to be other-than-temporary, if any, on available-for-sale securities are included in other income or expense. The cost of securities sold is based on the specific identification method. Interest and dividends on securities classified as available-for-sale are included in interest income. Prepaid Expenses and Other Current Assets Prepaid expenses and other current assets primarily represent amounts related to director and officer insurance, preclinical research and clinical trial agreements, equity issuance costs and an estimated tax refund for the year ended December 31, 2020 from the Australian Tax Office for eligible research and development expenditures. Property and Equipment Property and equipment is stated at cost and depreciated using the straight-line method over the estimated useful lives of the assets (generally three to five years). Impairment of Long-Lived Assets Long-lived assets consist primarily of property and equipment. An impairment loss is recorded if and when events and circumstances indicate that assets might be impaired and the undiscounted cash flows estimated to be generated by those assets are less than the carrying amount of those assets. While the Company’s current and historical operating losses and negative cash flows are indicators of impairment, management believes that future cash flows to be received support the carrying value of its long-lived assets and, accordingly, has not recognized any impairment losses since inception. Accrued Research and Development Expense The Company is required to estimate its expenses resulting from its obligations under contracts with vendors, consultants and contract research organizations, in connection with conducting research and development activities. The financial terms of these contracts are subject to negotiations, which vary from contract to contract and may result in payment flows that do not match the periods over which materials or services are provided under such contracts. The Company reflects research and development expenses in its consolidated financial statements by matching those expenses with the period in which services and efforts are expended. The Company accounts for these expenses according to the progress of the preclinical or clinical study as measured by the timing of various aspects of the study or related activities. The Company determines accrual estimates through review of the underlying contracts along with preparation of financial models taking into account discussions with research and other key personnel as to the progress of studies, or other services being conducted. During the course of a study, the Company adjusts its rate of expense recognition if actual results differ from its estimates. The Company classifies its estimates for accrued research and development expenses as accrued expenses on the accompanying consolidated balance sheet. Australian Research and Development Tax Incentive The Company is eligible under the Australian Research and Development Tax Incentive Program, or the Tax Incentive, to obtain a cash refund from the Australian Taxation Office for eligible research and development expenditures. To be eligible, the Company must have revenue of less than AUD $20.0 million during the reimbursable period and cannot be controlled by income tax exempt entities. The Tax Incentive is recognized as a reduction to research and development expense when there is reasonable assurance that the Tax Incentive will be received, the relevant expenditure has been incurred, and the amount can be reliably measured. The Company classifies its estimate for the Tax Incentive as prepaid expenses and other current assets on the accompanying consolidated balance sheet. Research and Development Research and development expenses include salaries and related overhead expenses, non-cash stock-based compensation expense, external research and development expenses incurred under arrangements with third parties, costs of services performed by consultants and contract research organizations, and regulatory costs including those related to preparing and filing INDs with the FDA. Research and development costs are expensed as incurred. 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 consolidated statement of operations. Stock-based Compensation The Company measures employee and nonemployee stock-based awards, including stock options and purchase rights, at grant-date fair value and records compensation expense on a straight-line basis over the vesting period of the award. The Company uses the Black-Scholes option pricing model to value its stock option awards. Estimating the fair value of stock option awards requires management to apply judgment and make estimates of certain assumptions, including the volatility of the Company’s common stock, the expected term of the Company’s stock options, the expected dividend yield and the fair value of the Company’s common stock on the measurement date. As a result, if factors change and management uses different assumptions, stock-based compensation expense could be materially different for future awards. Income Taxes The Company accounts for income taxes under the asset and liability method, which requires the recognition of deferred tax assets and liabilities for the expected future tax consequences of events that have been included in the consolidated financial statements. Under this method, deferred tax assets and liabilities are determined on the basis of the differences between the consolidated financial statements and tax basis of assets and liabilities using enacted tax rates in effect for the year in which the differences are expected to reverse. The effect of a change in tax rates on deferred tax assets and liabilities is recognized in income in the period that includes the enactment date. The Company recognizes deferred tax assets to the extent that the Company believes these assets are more likely than not to be realized. In making such a determination, management considers all available positive and negative evidence, including future reversals of existing taxable temporary differences, projected future taxable income, tax-planning strategies, and results of recent operations. If management determines that the Company would be able to realize its deferred tax assets in the future in excess of their net recorded amount, management would make an adjustment to the deferred tax asset valuation allowance, which would reduce the provision for income taxes. The Company records uncertain tax positions on the basis of a two-step process whereby (1) management determines whether it is more likely than not that the tax positions will be sustained on the basis of the technical merits of the position and (2) for those tax positions that meet the more- likely-than-not recognition threshold, management recognizes the largest amount of tax benefit that is more than 50 percent likely to be realized upon ultimate settlement with the related tax authority. The Company recognizes interest and penalties related to unrecognized tax benefits within income tax expense. Any accrued interest and penalties are included within the related tax liability. Net Loss per Share Basic net loss per share is calculated by dividing the net loss by the weighted-average number of common shares outstanding for the period. Diluted net loss per share is computed by dividing the net loss by the weighted average number of common shares and common share equivalents outstanding for the period. Common stock equivalents are only included when their effect is dilutive. The Company’s potentially dilutive securities include outstanding options under the Company’s equity incentive plan and outstanding warrants to purchase common stock, each of which have been excluded from the computation of diluted net loss per share as they would be anti-dilutive to the net loss per share. 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. Potentially dilutive securities not included in the calculation of diluted net loss per share attributable to common stockholders because to do so would be anti-dilutive are as follows (in common stock equivalent shares): Year Ended December 31, Year Ended December 31, 2020 2019 Common stock options 2,463,317 1,821,093 Common stock warrants 80,428 80,428 Total 2,543,745 1,901,521

Fair Value of Financial Instrum

Fair Value of Financial Instruments	12 Months Ended
	Dec. 31, 2020
Fair Value Disclosures [Abstract]
Fair Value of Financial Instruments	3. Fair Value of Financial Instruments The accounting guidance 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 defined as an exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. As such, fair value is a market-based measurement that should be determined based on assumptions that market participants would use in pricing an asset or liability. As a basis for considering such assumptions, the accounting guidance establishes a three-tier fair value hierarchy, which prioritizes the inputs used in measuring fair value as follows: Level 1 —Unadjusted quoted prices in active markets that are accessible at the measurement date for identical, unrestricted assets or liabilities. Level 2 —Quoted prices for similar assets and liabilities in active markets, quoted prices in markets that are not active, or inputs which are observable, either directly or indirectly, for substantially the full term of the asset or liability. Level 3 —Prices or valuation techniques that require inputs that are both significant to the fair value measurement and unobservable (i.e. supported by little or no market activity). Financial assets measured at fair value on a recurring basis consist of the Company’s cash equivalents and short-term investments. Cash equivalents consisted of money market funds and short-term investments consisted of U.S. treasury securities, agency securities and certificates of deposit . The The following tables summarize the Company’s assets that require fair value measurements on a recurring basis and their respective input levels based on the fair value hierarchy (in thousands): Fair Value Measurements Using Quoted Prices in Significant Significant Active Markets Other Unobservable December 31, for Identical Observable Inputs 2020 Assets (Level 1) Inputs (Level 2) (Level 3) Short-term investments: U.S. treasury securities $ 56,220 $ 56,220 $ - $ - Certificates of deposit 1,961 1,961 - - Total $ 58,181 $ 58,181 $ - $ - Fair Value Measurements Using Quoted Prices in Significant Significant Active Markets Other Unobservable December 31, for Identical Observable Inputs 2019 Assets (Level 1) Inputs (Level 2) (Level 3) Short-term investments: U.S. treasury securities $ 28,549 $ 28,549 $ - $ - Agency securities 5,994 - 5,994 - Certificates of deposit 5,381 5,381 - - Total $ 39,924 $ 33,930 $ 5,994 $ - U.S. treasury securities and certificates of deposit are valued using Level 1 inputs. Level 1 securities are valued at unadjusted quoted prices in active markets that are observable at the measurement date for identical, unrestricted assets or liabilities. Fair values determined by Level 2 inputs, which utilize data points that are observable such as quoted prices, interest rates and yield curves, require the exercise of judgment and use of estimates, that if changed, could significantly affect the Company’s financial position and results of operations. Investments in agency securities are valued using Level 2 inputs. Level 2 securities are initially valued at the transaction price and subsequently valued and reported utilizing inputs other than quoted prices that are observable either directly or indirectly, such as quotes from third-party pricing vendors. The carrying amounts of the Company’s financial instruments, including cash, prepaid and other current assets, accounts payable, and accrued liabilities, approximate fair value due to their short maturities. At December 31, 2020 and 2019, the carrying amount of the Company’s notes payable of $9.9 million and $9.7 million, respectively, approximated their fair value as the terms of the notes are consistent with the market terms of transactions with similar profiles (Level 2 inputs). None of the Company’s non-financial assets or liabilities are recorded at fair value on a non-recurring basis. At December 31, 2020 and 2019, the Company had investments in money market funds of $17.4 million and $10.3 million, respectively, that were measured at fair value using the net asset value per share (or its equivalent) that have not been classified in the fair value hierarchy. The funds invest primarily in U.S. government securities. The Company did not hold any Level 1, 2 or 3 financial liabilities that are recorded at fair value on a recurring basis as of December 31, 2020 or 2019.

Short-Term Investments

Short-Term Investments	12 Months Ended
	Dec. 31, 2020
Investments Debt And Equity Securities [Abstract]
Short-Term Investments	4. Short-term Investments The following table summarizes the Company’s short-term investments (in thousands): Maturity Amortized Unrealized Unrealized Estimated (in years) Cost Gains Losses Fair Value December 31, 2020 U.S. treasury securities 1 or less $ 56,218 $ 6 $ (4 ) $ 56,220 Certificates of deposit 1 or less 1,955 6 - 1,961 Total $ 58,173 $ 12 $ (4 ) $ 58,181 December 31, 2019 U.S. treasury securities 1 or less $ 23,513 $ 6 $ (4 ) $ 23,515 U.S. treasury securities >1 and <5 5,035 - (1 ) 5,034 Agency securities 1 or less 5,976 19 (1 ) 5,994 Certificates of deposit 1 or less 4,131 22 - 4,153 Certificates of deposit >1 and <5 1,220 8 - 1,228 Total $ 39,875 $ 55 $ (6 ) $ 39,924 All of the Company’s available-for-sale securities are available to the Company for use in its current operations. As a result, the Company categorizes all of these securities as current assets even though the stated maturity of some individual securities may be one year or more beyond the balance sheet date. All of the Company’s securities have a maturity within two years of the balance sheet date. There were no impairments considered other-than-temporary during the year ended December 31, 2020, as it is management’s intention and ability to hold the securities until a recovery of the cost basis or recovery of fair value. Unrealized gains and losses are included in accumulated other comprehensive (loss) income.

Property and Equipment

Property and Equipment	12 Months Ended
	Dec. 31, 2020
Property Plant And Equipment [Abstract]
Property and Equipment	5. Property and Equipment Property and equipment consisted of the following (in thousands): December 31, December 31, 2020 2019 Furniture & fixtures $ 60 $ 60 Machinery & lab equipment 211 24 Computer equipment 42 38 Less accumulated depreciation and amortization (74 ) (29 ) Property and equipment, net $ 239 $ 93 Depreciation expense related to property and equipment was approximately $45,000 and $23,000 for the years ended December 31, 2020 and 2019, respectively. No material gains or losses on the disposal of property and equipment have been recorded for the years ended December 31, 2020 or 2019.

Accrued Expenses

Accrued Expenses	12 Months Ended
	Dec. 31, 2020
Accrued Liabilities Current [Abstract]
Accrued Expenses	6. Accrued Expenses Accrued expenses consisted of the following (in thousands): December 31, December 31, 2020 2019 Accrued payroll and other employee benefits $ 1,870 $ 1,215 Clinical studies 493 442 Other accruals 307 267 Preclinical studies 72 15 Accrued interest 71 71 Total accrued expenses $ 2,813 $ 2,010

Collaboration and License Agree

Collaboration and License Agreement	12 Months Ended
	Dec. 31, 2020
Collaboration And License Agreement [Abstract]
Collaboration and License Agreement	7. Collaboration and License Agreement In May 2017, the Company entered into a collaboration and license agreement (which was amended in September 2018, April 2019 and December 2019), clinical supply agreement, investor rights agreement, and common stock purchase agreement (collectively License Agreements) with Biocon SA (subsequently assigned to Biocon Limited, or together, Biocon). Pursuant to the License Agreements, Biocon granted the Company an exclusive license to develop, make, have made, use, sell, have sold, offer for sale, import and otherwise exploit itolizumab and any pharmaceutical composition or preparation containing or comprising itolizumab that uses Biocon technology or Biocon know-how (collectively a Biocon Product) in the United States, Canada, Australia and New Zealand (collectively Company Territory). However, unless the Company achieves certain regulatory and development milestones within a specific time period, the licensed rights, other than development rights, are limited to the fields of orphan indications and the treatment of conditions related to asthma and lupus. The Company also has the right to sublicense through multiple tiers to third parties, provided such sublicenses comply with the terms of the License Agreements and the Company provides Biocon a copy of each sublicense agreement within 30 days of execution. If the Company grants a third party a sublicense of its rights to develop and commercialize Biocon Products in Australia or New Zealand, the Company will be required to pay Biocon a high double-digit percentage of any upfront payment the Company receives from such sublicensee for such sublicense, as well as a high double-digit percentage of any additional payments the Company receives from such sublicensee for such sublicense, including but not limited to royalty payments on net sales of Biocon Products by such sublicensee. Under the License Agreements, the Company granted back to Biocon a license to use its technology and know-how related to itolizumab and Biocon Products in certain countries outside of the Equillium Territory. Pursuant to the License Agreements, Biocon agreed to be the Company’s exclusive supplier of itolizumab clinical drug product. Biocon will provide clinical drug product at no cost for up to three concurrent orphan indications until the Company’s first U.S. regulatory approval and all other clinical drug product at Biocon’s cost. In consideration of the rights granted to the Company by Biocon, the Company issued Biocon a total of 2,316,134 shares of its common stock. In addition, the Company is obligated to pay Biocon up to an aggregate of $30 million in regulatory milestone payments upon the achievement of certain regulatory approvals and up to an aggregate of $565 million in sales milestone payments upon the achievement of first commercial sale of product and specified levels of product sales. The Company is also required to pay royalties on tiers of aggregate annual net sales of Biocon Products by us, our affiliates and our sublicensees in the United States and Canada at percentages from the mid-single digits to sub-teen double-digits and on tiers of aggregate annual net sales of Biocon Products by us and our affiliates (but not our sublicensees) in Australia and New Zealand, in each case, subject to adjustments in certain circumstances. Biocon is also required to pay the Company royalties at comparable percentages for sales of itolizumab (EQ001) outside of the Company Territory if the approvals in such geographies included or referenced the Company’s data including data from certain of the Company’s clinical trials, subject to adjustments in certain circumstances. Under the License Agreements, net sales are calculated on a country-by-country basis and are subject to adjustments, including whether the Biocon Product is sold in the form of a combination product. As of December 31, 2020, the Company has not made or received payments in connection with the milestones or royalties within the agreement.

Notes Payable

Notes Payable	12 Months Ended
	Dec. 31, 2020
Debt Disclosure [Abstract]
Notes Payable	8. Notes Payable On September 30, 2019 (the Effective Date), the Company Under the terms of the Loan Agreement, the Company may, at its sole discretion, borrow from the Lenders (i) up to an additional $5.0 million (Term B Loan) upon the Company’s achievement of positive topline data in either the Company’s (a) Phase 1b aGVHD trial of itolizumab (EQ001) or (b) Phase 1b asthma trial of itolizumab (EQ001), supporting a formal decision to advance into Phase 2 development, and as confirmed by the Board of Directors (the Board) of the Company (the Term B Milestone) and (ii) up to an additional $5.0 million (Term C Loan and together with Term A Loan and Term B Loan, the Term Loans) upon the Company’s achievement of positive topline data in both the Company’s Phase 1b aGVHD trial of itolizumab (EQ001) and the Company’s Phase 1b asthma trial of itolizumab (EQ001), supporting a formal decision to advance into Phase 2 development, and as confirmed by the Board (the Term C Milestone). The Company may draw the Term B Loan during the period commencing on the date of the occurrence of the Term B Milestone and ending on the earliest of (i) December 31, 2020, (ii) 60 days after achieving the Term B Milestone, and (iii) the occurrence of an event of default and may draw the Term C Loan during the period commencing on the date of the occurrence of the Term C Milestone and ending on the earliest of (i) December 31, 2020, (ii) 60 days after achieving the Term C Milestone, and (iii) the occurrence of an event of default. As of December 31, 2020, the Company did not achieve the Term B or Term C Milestone and is not eligible to receive the additional funding up to $10 million under the Loan Agreement. All of the Term Loans mature on June 1, 2024 (the Maturity Date) and require interest-only payments through June 30, 2021, followed by 36 equal monthly payments of principal and interest; provided that if the Company draws the Term B Loan, the Term Loans will require interest-only payments through December 31, 2021, followed by 30 equal monthly payments of principal and interest. The Term Loans will bear interest at a floating per annum rate equal to the greater of (i) 8.25% and (ii) the sum of (a) the prime rate reported in The Wall Street Journal on the last business day of the month that immediately precedes the month in which the interest will accrue, plus (b) 3.00%. On December 18, 2020, the Company entered into the First Amendment to the Loan Agreement (the Amendment) with the Lenders whereby if the Company achieves the Term B Milestone on or prior to June 30, 2021, the interest-only payments will be automatically extended to January 1, 2022. The Company has not yet achieved the Term B Milestone subsequent to December 31, 2020 and through the date of the filing of this Annual Report on Form 10-K. The Company will be required to make a final payment of 4.50% of the original principal amount of the Term Loans drawn payable on the earlier of (i) the Maturity Date, (ii) the acceleration of any Term Loans, or (iii) the prepayment of the Term Loans (the Final Payment). The Company may prepay all, but not less than all, of the Term Loans upon 30 days’ advance written notice to the lender, provided that the Company will be obligated to pay a prepayment fee equal to (i) 3.00% of the principal amount of the applicable Term Loan prepaid on or before the first anniversary of the applicable funding date, (ii) 2.00% of the principal amount of the applicable Term Loan prepaid between the first and second anniversary of the applicable funding date, and (iii) 1.00% of the principal amount of the applicable Term Loan prepaid thereafter, and prior to the Maturity Date (each, a Prepayment Fee). In connection with entering into the Loan Agreement, the Company issued to the Lenders warrants exercisable for 80,428 shares of the Company’s common stock (the Warrants). The Warrants are exercisable in whole or in part, immediately, and have a per share exercise price of $3.73, which is the closing price of the Company’s common stock reported on the Nasdaq Global Market on the day prior to the Effective Date. The Warrants will terminate on the earlier of September 30, 2029 or the closing of certain merger or consolidation transactions. If the Company borrows under Term B Loan and/or Term C Loan, upon the funding of Term B Loan and/or Term C Loan, as applicable, the Company will issue to the Lenders additional warrants to purchase shares of the Company’s common stock equal to 3.00% of each Term Loan amount divided by the lower of (i) the ten day average closing price of the Company’s common stock reported on the Nasdaq Global Market prior to funding or (ii) the closing price of the Company’s common stock reported on the Nasdaq Global Market on the day prior to funding. Such lower amount of (i) and (ii) above shall also be the exercise price per share for such warrants. The terms of such warrants would be substantially the same as those contained in the Warrants. The Company recorded the Warrants as a debt discount, which is classified as a contra-liability against long-term notes payable on the consolidated balance sheet and is amortizing the balance over the life of the underlying debt. The offset to the contra-liability is recorded in additional paid in capital in the Company’s consolidated balance sheet as the Warrants were determined to be equity classified. The Company determined the fair value of the Warrants at the date of issuance was $0.3 million using the Black-Scholes option pricing model based on significant unobservable inputs (Level 3) with an expected term of 10 years, volatility of 92.78%, risk free rate of 1.68% and expected dividend of 0%. The costs incurred to issue the Term Loans of $0.1 million were deferred and are included in the discount to the carrying value of the Term Loans in the accompanying consolidated balance sheet. The deferred costs and the Final Payment fee are amortized to interest expense over the expected term of the Term Loans using the effective interest method with an effective interest rate of 10.97%. The aggregate carrying amounts of the Term Loans are comprised of the following (in thousands): December 31, December 31, 2020 2019 Principal $ 10,000 $ 10,000 Add: accreted liability for final payment fee 176 35 Less: unamortized discount (235 ) (354 ) Total $ 9,941 $ 9,681 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, cross defaults to other indebtedness or material agreements, judgment defaults and defaults related to failure to maintain governmental approvals failure of which to maintain could result in a material adverse effect, the Company’s lenders will have the right, among other remedies, to declare all principal and interest immediately due and payable, to exercise secured party remedies, to receive the Final Payment and, if the payment of principal and interest is due prior to the Maturity Date, to receive the applicable Prepayment Fee. At December 31, 2020, the Company was in compliance with the covenants contained in the Loan Agreement. Future maturities of the Term Loans, including the Final Payment fee, as of December 31, 2020 were as follows (in thousands): December 31, 2020 Year ending December 31, 2021 $ 1,667 Year ending December 31, 2022 3,333 Year ending December 31, 2023 3,333 Year ending December 31, 2024 2,117 10,450 Unaccreted balance for Final Payment fee on Term Loans (274 ) Unamortized discounts (235 ) 9,941 Less current portion (1,666 ) Noncurrent portion $ 8,275

Stockholders_ Equity

Stockholders’ Equity	12 Months Ended
	Dec. 31, 2020
Equity [Abstract]
Stockholders’ Equity	9. Stockholders’ Equity As of December 31, 2020, the Company’s authorized capital stock consisted of 200,000,000 shares of common stock, par value $0.0001 per share, and 10,000,000 shares of preferred stock, par value $0.0001 per share. The Company had 24,753,102 and 17,425,654 shares of common stock outstanding as of December 31, 2020 and 2019, respectively. Follow-On Public Offering In August 2020, the Company completed an underwritten public offering of 5,461,169 shares of common stock at $7.00 per share, which included 461,169 shares sold pursuant to the exercise of the underwriters’ option to purchase additional shares. The Company received gross proceeds from this offering totaling $38.2 million. The proceeds, net of underwriting discounts and related issuance costs, were $35.7 million. At-the-Market Offering Program In November 2019, the Company entered into an Open Market Sales Agreement SM The maximum aggregate offering price of common stock that could be sold under the 2019 ATM Facility was $8.45 million. In December 2019, the Company sold an aggregate of 18,250 shares of its common stock under the 2019 ATM Facility resulting in net negative proceeds of $0.2 million, after deducting the facility’s costs. During the year ended December 31, 2020, the Company sold an aggregate 925,489 shares of its common stock and received gross proceeds of $8.4 million under the 2019 ATM Facility. The Company paid commissions on the gross proceeds in the aggregate amount of approximately $0.3 million, during the year ended December 31, 2020, resulting in net proceeds of $8.1 million. As of December 31, 2020, the 2019 ATM Facility was fully utilized. On July 14, 2020, the Company entered into a new ATM equity offering program (2020 ATM Facility) with Jefferies under which the Company may offer and sell shares of the Company’s common stock having an aggregate price of up to $150 million, from time to time, through Jefferies acting as our sales agent. For the year ended December 31, 2020, the Company sold an aggregate of 788,685 shares of common stock under the 2020 ATM Facility and received gross proceeds of $10.4 million. The Company paid cash commissions on the gross proceeds, plus reimbursement expenses to Jefferies and other issuance costs in the aggregate amount of approximately $0.4 million, resulting in net proceeds of $10.0 million. Since December 31, 2020 and through the date of the filing of this Annual Report on Form 10-K, there have been no additional sales of the Company’s stock under the 2020 ATM Facility. Purchase Agreement In March 2020, the Company entered into a purchase agreement (Purchase Agreement), with Lincoln Park Capital Fund, LLC (Lincoln Park), which provides that, upon the terms and subject to the conditions and limitations set forth therein, the Company may sell to Lincoln Park up to $15.0 million of shares of its common stock from time to time over the 36-month term of the Purchase Agreement. Upon execution of the Purchase Agreement, the Company issued 65,374 shares of its common stock to Lincoln Park as commitment shares in accordance with the closing conditions contained within the Purchase Agreement. The commitment shares were valued using the closing price of the Company’s common stock on the effective date of the Purchase Agreement resulting in a fair market value of approximately $0.2 million. The fair market value of the commitment shares as well as other issuance costs associated with the Purchase Agreement totaled $0.4 million. These issuance costs are classified as prepaid expenses and other current assets in the accompanying consolidated balance sheet. As shares of common stock are sold to Lincoln Park in accordance with the Purchase Agreement, the issuance costs, including the fair value of the commitment shares, will be reclassified to additional paid-in capital on the Company’s consolidated balance sheet . There have been no sales of the Company’s stock under this Purchase Agreement as of December 31, 2020 and through the date of the filing of this Annual Report on Form 10-K. 2018 Equity Incentive Plan In October 2018, the Company adopted the 2018 Equity Incentive Plan (the 2018 Plan) which replaced the Company’s legacy 2017 Equity Incentive Plan (the 2017 Plan). The 2018 Plan provides for the grant of incentive stock options, non-statutory stock options, stock appreciation rights, restricted stock awards, restricted stock unit awards, performance stock awards, performance cash awards and other forms of stock awards. As of December 31, 2020, the 2018 Plan had a maximum of 1,039,531 total shares available for issuance. The number of shares of common stock reserved for issuance under the 2018 Plan will automatically increase on January 1 of each calendar year through January 1, 2028, in an amount equal to 5.0% of the total number of shares of the Company’s capital stock outstanding on the last day of the calendar month before the date of each automatic increase, or a lesser number of shares determined by the Board. Options granted under the 2018 Plan are exercisable at various dates as determined upon grant and will expire no more than ten years from their date of grant. The exercise price of each option shall be determined by the Board based on the estimated fair value of the Company’s stock on the date of the option grant. The exercise price shall not be less than 100% of the fair market value of the Company’s common stock at the time the option is granted. Most option grants generally vest 25% on the first anniversary of the original vesting commencement date, with the balance vesting monthly over the remaining three years. Repricing of Outstanding Options On April 22, 2020, the Board approved a repricing of outstanding options to purchase 1,475,093 shares of the Company’s common stock held by employees of the Company, including executive officers (but excluding any employees who serve on the Board) that had exercise prices in excess of the closing stock price on April 22, 2020 and were granted under the Company’s equity incentive plans. As a result of the repricing, the exercise price of such options was lowered to $2.45 per share, the closing price of the Company’s common stock on April 22, 2020. The vesting schedule and term of these options remained unchanged. The Board effectuated the repricing to realign the value of such options with their intended purpose, which is to retain and motivate the holders of such options to continue to work in the best interests of the Company and its stockholders. Prior to the repricing, many of the options had exercise prices well above the market prices of the Company’s common stock at that time, including prior to the market volatility that had generally been associated with the onset of the COVID-19 pandemic. The effect of the repricing generated a total incremental cost of approximately $0.4 million, of which approximately $0.2 million was recognized as stock-based compensation expense in the year ended December 31, 2020, with the remainder to be expensed over the remaining vesting periods. Stock Options The following summarizes stock option activity for the year ended December 31, 2020: Outstanding Options Weighted- Average Exercise Price Per Share Weighted Average Remaining Contractual Term (in years) Aggregate Intrinsic Value (in thousands) (a) Balances as of December 31, 2019 1,821,093 $ 5.64 9.24 $ 17 Granted 852,368 $ 4.29 Exercised (3,000 ) $ 2.45 Forfeitures and cancellations (207,144 ) $ 2.45 Balances as of December 31, 2020 (b) 2,463,317 $ 3.71 7.98 $ 4,726 Options exercisable as of December 31, 2020 (b) 1,041,624 $ 3.52 6.91 $ 2,177 (a) Aggregate intrinsic value in this table was calculated as the positive difference, if any, between the closing price per share of the Company’s common stock on December 31, 2020 of $5.35 and the price of the underlying options. (b) The weighted-average exercise price per share of the options outstanding and exercisable as of December 31, 2020 includes the impact of the repricing of 1,475,093 options on April 22, 2020 at $2.45 per share. The aggregate intrinsic value of stock options exercised was $9,000 and $0 for the years ended December 31, 2020 and 2019, respectively. Cash received from stock options exercised was $7,000 and $69,000 for the years ended December 31, 2020 and 2019, respectively. The fair value of stock options that vested in the years ended December 31, 2020 and 2019 was $4.1 million and $1.4 million, respectively. T As of December 31, 2020, unrecognized compensation expense related to unvested stock options was $6.6 million and is expected to be recognized over a weighted-average period of 2.3 years. 2018 Employee Stock Purchase Plan In October 2018, the Company adopted the 2018 Equity Stock Purchase Plan (ESPP) whereby eligible employees may elect to withhold up to 15% of their earnings to purchase shares of the Company’s common stock at a price per share equal to the lower of (i) 85% of the fair market value of a share of the Company’s common stock on the first date of an offering or (ii) 85% of the fair market value of a share of the Company’s common stock on the date of the purchase right (purchase right). Initially, 343,275 shares of the Company’s common stock were approved for issuance under the ESPP pursuant to purchase rights granted to the Company’s employees or to employees of any of the Company’s designated affiliates. The number of shares of the Company’s common stock reserved for issuance will automatically increase on January 1 of each calendar year through January 1, 2028, by the lesser of (1) 1.0% of the total number of shares of the Company’s common stock outstanding on the last day of the calendar month before the date of the automatic increase, and (2) 343,275 shares; provided that before the date of any such increase, the Board may determine that such increase will be less than the amount set forth in clauses (1) and (2). As of December 31, 2020, the Company had issued 78,764 shares of common stock under the ESPP, 65,443 of which were issued during the year ended December 31, 2020. The Company had 612,529 shares available for future issuance under the ESPP as of December 31, 2020. Liability for Early Exercise of Restricted Stock Options All stock option grants under the 2017 Plan provide for exercise of the stock option prior to vesting. Shares of common stock issued upon exercise of unvested options are subject to repurchase by the Company at the respective original exercise price until vested. Consideration received for the exercise of unvested stock options is recorded as a liability and reclassified into equity as the related award vests. As of December 31, 2020 and 2019, 153,690 and 265,232 unvested shares issued under early exercise provisions were subject to repurchase by the Company, respectively. The balance sheet reflects an unvested stock liability of $0.1 million and $0.2 million as of December 31, 2020 and 2019, respectively. The short-term portion of the unvested stock liability totals approximately $72,000 as of December 31, 2020, and is classified as accrued expenses on the accompanying consolidated balance sheet. The long-term portion of the unvested stock liability totals approximately $53,000 as of December 31, 2020, and is classified as other non-current liabilities on the accompanying consolidated balance sheet. Stock-based Compensation Expense On May 28, 2020, the Compensation Committee of the Board issued to its Executive Chairman, Chief Executive Officer and two non-management directors retention stock options to purchase an aggregate of 169,368 shares of the Company’s common stock. These stock option grants immediately vested at the date of grant. The non-cash stock-based compensation expense recognized in the year ended December 31, 2020 associated with these stock option grants totaled $0.4 million. At the time, the Executive Chairman and Chief Executive Officer voluntarily agreed to a 65% and an 85% reduction, respectively, in their base salaries otherwise payable for the remainder of 2020. The two non-management directors voluntarily agreed to forego 100% of their annual cash retainers otherwise payable to such directors for the remainder of 2020. Total non-cash stock-based compensation expense for all stock awards and purchase rights, net of forfeitures recognized as they occur, that was recognized in the consolidated statement of operations is as follows (in thousands): Year Ended December 31, Year Ended December 31, 2020 2019 Research and development $ 1,773 $ 1,207 General and administrative 2,044 1,045 Total $ 3,817 $ 2,252 The weighted-average assumptions used in the Black-Scholes option pricing model to determine the fair value of the employee and nonemployee stock option grants were as follows: Year Ended December 31, Year Ended December 31, 2020 2019 Risk-free interest rate 0.65% 2.23% Expected volatility 89.56% 93.58% Expected term (in years) 5.77 5.77 Expected dividend yield 0% 0% Risk-free interest rate. The risk-free rate assumption is based on the U.S. Treasury instruments, the terms of which were consistent with the expected term of the Company’s stock options. Expected volatility. Due to the Company’s limited operating history and lack of company-specific historical or implied volatility as a private company, the expected volatility assumption was determined by examining the historical volatilities of a group of industry peers whose share prices are publicly available. Expected term. The expected term of stock options represents the weighted-average period the stock options are expected to be outstanding. The Company uses the simplified method for estimating the expected term as provided by the SEC. The simplified method calculates the expected term as the average of the time-to-vesting and the contractual life of the options. Expected dividend yield. The expected dividend assumption is based on the Company’s history and expectation of dividend payouts. The Company has not paid and does not intend to pay dividends. Forfeitures . The Company reduces stock-based compensation expense for actual forfeitures during the period. Common Stock Reserved for Future Issuance Common stock reserved for future issuance consists of the following as of December 31, 2020 and 2019: December 31, December 31, 2020 2019 Stock options issued and outstanding 2,463,317 1,821,093 Warrants for common stock 80,428 80,428 Awards available under the 2018 Equity Incentive Plan 1,039,531 813,473 Employee stock purchase plan 612,529 503,716 Total 4,195,805 3,218,710

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2020
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	10. Commitments and Contingencies Leases and Other Commitments The Company leases certain office space in La Jolla and South San Francisco, California under non-cancelable operating leases. The leases for spaces in La Jolla and South San Francisco expire in February 2022. Rent expense was $0.2 million for both the years ended December 31, 2020 and 2019. The future minimum lease payments required under non-cancelable leases as of December 31, 2020, are summarized as follows (in thousands): Years Ending December 31, 2021 $ 153 2022 26 Total $ 179 The Company enters into service agreements with indemnification clauses in the ordinary course of business. Pursuant to such clauses, the Company indemnifies, defends, holds harmless, and agrees to reimburse the indemnified party for losses suffered or incurred by third party claims arising out of the indemnified party’s Litigation As of December 31, 2020, there was no litigation against the Company .

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Income Taxes	11. Income Taxes The components of loss before income tax provision (benefit) for the years ended December 31, 2020 and 2019 consisted of the following (in thousands): Year Ended December 31, Year Ended December 31, 2020 2019 U.S. (29,420 ) (23,167 ) Foreign (393 ) (2,433 ) $ (29,813 ) $ (25,600 ) The Company has not recorded a current or deferred tax expense or benefit for the years ended December 31, 2020 and 2019. The following is a reconciliation of the expected statutory federal income tax provision to our actual income tax provision for the years ended December 31, 2020 and 2019 (in thousands): Year Ended December 31, Year Ended December 31, 2020 2019 Income taxes at statutory rates $ (6,261 ) $ (5,376 ) State income tax, net of federal benefit - 1 Stock-based compensation 97 276 Permanent items 15 54 Federal research and orphan drug credits (445 ) (684 ) Foreign rate differential 367 (158 ) Change in federal valuation allowance 6,227 5,887 $ - $ - The tax effects of temporary differences that give rise to significant portions of the deferred tax assets and deferred tax liabilities as of December 31, 2020 and 2019 are as follows (in thousands): December 31, December 31, 2020 2019 Deferred tax assets: Net operating loss carryforward $ 12,338 $ 7,212 Credits 1,940 1,227 Intangibles 118 129 Equity compensation 888 188 Other 286 221 Total deferred tax assets 15,570 8,977 Valuation allowance (15,564 ) (8,976 ) Total deferred tax assets, net of allowance $ 6 $ 1 Deferred tax liabilities: Other (6 ) (1 ) Total deferred tax liabilities $ (6 ) $ (1 ) Net deferred taxes $ - $ - The Company has established a valuation allowance against its net deferred tax assets due to the uncertainty surrounding the realization of such assets. The Company periodically evaluates the recoverability of the deferred tax assets. At such time as it is determined that it is more likely than not that deferred assets are realizable, the valuation allowance will be reduced. The Company has recorded a full valuation allowance of $15.6 million as of December 31, 2020 as it does not believe it is more likely than not that certain deferred tax assets will be realized primarily due to the generation of pre-tax book losses in the current year, the lack of feasible tax-planning strategies, the limited existing taxable temporary differences, and the subjective nature of forecasting future taxable income into the future. The Company increased its valuation allowance by approximately $6.6 million during the year ended December 31, 2020. At December 31, 2020, the Company had federal and California tax loss carry forwards of approximately $53.9 million and $30.7 million, respectively. The federal net operating loss carryover includes $53.0 million of net operating losses generated subsequent to 2017. Federal net operating losses generated after December 31, 2017 carryover indefinitely and may generally be used to offset up to 80% of future taxable income. The federal net operating losses generated prior to 2018 as well as the state net operating loss carry forwards, begin to expire in 2037 unless previously utilized. The Company has $1.9 million of Australian net operating loss carryforwards as of December 31, 2020 that are carried forward indefinitely. At December 31, 2020, the Company had federal and state tax credit carry forwards of approximately $1.4 million and $0.6 million, respectively, after reduction for uncertain tax positions. The Company has not performed a formal research and development credit study with respect to these credits. The federal credits will begin to expire in 2037, if unused, and the state credits carry forward indefinitely. Pursuant to the Internal Revenue Code of 1986, as amended (IRC), specifically Section 382 and 383, the Company's ability to use net operating loss and research and development tax credit carry forwards (tax attribute carry forwards) to offset future taxable income is limited if the Company experiences a cumulative change in ownership of more than 50% within a three-year testing period. The Company has not completed an ownership change analysis pursuant to IRC Section 382. If ownership changes within the meaning of IRC Section 382 are identified as having occurred, the amount of remaining tax attribute carry forwards available The following table summarizes the reconciliation of the unrecognized tax benefits activity during the years ended December 31, 2020 and 2019 (in thousands): Year Ended December 31, Year Ended December 31, 2020 2019 Unrecognized tax benefits – beginning $ 360 $ 89 Gross increases – tax positions in prior period 1,988 - Gross decreases – tax positions in prior period - - Gross increase – current-period tax positions 319 271 Gross decrease – current-period tax positions - - Settlements - - Lapse of statute of limitations - - Unrecognized tax benefits – ending $ 2,667 $ 360 The unrecognized tax benefit amounts are reflected in the determination of the Company’s deferred tax assets. If recognized, none of these amounts would affect the Company’s effective tax rate, since it would be offset by an equal corresponding adjustment in the deferred tax asset valuation allowance. The Company does not foresee material changes to its liability for uncertain tax benefits within the next twelve months. The Company's policy is to recognize interest and/or penalties related to income tax matters in income tax expense. The Company had no accrual for interest or penalties on the Company's consolidated balance sheet as of December 31, 2020 and has not recognized interest and/or penalties in the consolidated statement of operations for the year ended December 31, 2020. All tax years for both federal and state purposes remain open and subject to examination by tax jurisdictions. On March 27, 2020, the United States enacted the Coronavirus Aid, Relief and Economic Security Act (CARES Act). The CARES Act is an emergency economic stimulus package that includes spending and tax breaks to strengthen the United States economy and fund a nationwide effort to curtail the effect of COVID-19. While the CARES Act provides sweeping tax changes in response to the COVID-19 pandemic, some of the more significant provisions are the extension of the carryback period of certain losses to five years, and the suspension of the 80 percent limitation imposed by the Tax Cuts and Jobs Act of 2017 (TCJA) on utilization of net operating losses generated in 2018, 2019 and 2020 to offset taxable income generated in tax years prior to 2021. The CARES Act also increased the ability to deduct interest expense from 30 percent, as imposed by the TCJA, to 50 percent of modified taxable income. The CARES Act also provides a credit against employee wages, the opportunity to defer payment of a portion of federal payroll taxes to December 2021 and December 2022, and enhanced small business loans to assist businesses impacted by the pandemic. The Company’s tax provision and financial position was not materially impacted by the CARES Act. On December 27, 2020, the United States enacted the Consolidated Appropriations Act, which extended and modified many of the tax related provisions of the CARES Act. The Company does not anticipate a material impact of the Consolidated Appropriations Act on its tax provision or financial position.

Retirement Plan

Retirement Plan	12 Months Ended
	Dec. 31, 2020
Compensation And Retirement Disclosure [Abstract]
Retirement Plan	12. Retirement Plan The Company sponsors an employee savings plan that qualifies as a deferred salary arrangement under Section 401(k) of the IRC. Participating employees may defer up to the Internal Revenue Service annual contribution limit. The Company did not made any contributions for the years ended December 31, 2020 or 2019.

Selected Quarterly Financial Da

Selected Quarterly Financial Data (unaudited)	12 Months Ended
	Dec. 31, 2020
Quarterly Financial Information Disclosure [Abstract]
Selected Quarterly Financial Data (unaudited)	13. Selected Quarterly Financial Data (unaudited) The following table contains unaudited quarterly financial information for the years ended December 31, 2020 and 2019. The Company believes that the following information reflects all normal recurring adjustments necessary for a fair statement of the information for the periods presented. The operating results for any quarter are not necessarily indicative of results for any future period. in thousands (except per share amounts) First Quarter Second Quarter Third Quarter Fourth Quarter Year Ended December 31, 2020 Operating expenses $ 7,452 $ 6,610 $ 6,516 $ 8,970 Net loss (7,837 ) (6,461 ) (6,597 ) (8,918 ) Net loss per common share, basic and diluted $ (0.45 ) $ (0.37 ) $ (0.31 ) $ (0.36 ) Year Ended December 31, 2019 Operating expenses $ 6,348 $ 6,439 $ 6,324 $ 7,616 Net loss (5,950 ) (6,069 ) (6,014 ) (7,567 ) Net loss per common share, basic and diluted $ (0.34 ) $ (0.35 ) $ (0.35 ) $ (0.44 )

Subsequent Events

Subsequent Events	12 Months Ended
	Dec. 31, 2020
Subsequent Events [Abstract]
Subsequent Events	14. Subsequent Events On February 3, 2021, the Company entered into a securities purchase agreement (the Securities Purchase Agreement) with two institutional investors (the Purchasers), relating to the issuance and sale (the Offering) of an aggregate of 4,285,710 shares of common stock and warrants to purchase 1,285,713 shares of common stock (the Warrants) for aggregate gross proceeds to the Company from this Offering of approximately $30.0 million, excluding any proceeds the Company may receive upon exercise of the Warrants. No underwriter or placement agent participated in the Offering. The Warrants are exercisable immediately upon issuance at an initial exercise price of $14.00 per share and are exercisable on a cashless basis. The Warrants expire on the earlier of (i) the fifth anniversary of issuance or (ii) the 15 th The exercise price and the number of shares of common stock purchasable upon the exercise of the Warrants are subject to adjustment upon the occurrence of specific events, including stock dividends, stock splits, reclassifications and combinations of the Company’s common stock. Pursuant to the terms of the Securities Purchase Agreement, the Company agreed to appoint Dr. Yu (Katherine) Xu, Ph. D. to the Board as a nominee of the Purchasers.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2020
Accounting Policies [Abstract]
Recent Accounting Pronouncements	Recent Accounting Pronouncements In February 2016, the FASB issued ASU 2016-02, Leases (Topic 842) Financial Instruments—Credit Losses (Topic 326) Derivatives and Hedging (Topic 815) Leases (Topic 842 Effective Dates (ASU 2019-10), In June 2016, the FASB issued ASU No. 2016-13, Measurement of Credit Losses on Financial Instruments . In December 2019, the FASB issued ASU No. 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes Adopted Accounting Pronouncements In August 2018, the FASB issued ASU 2018-13, Fair Value Measurement (Topic 820) – Disclosure Framework – Changes to the Disclosure Requirements for Fair Value Measurement
Use of Estimates	Use of Estimates The preparation of the Company’s consolidated financial statements requires the Company to make estimates and assumptions that impact the reported amounts of assets, liabilities and expenses and the disclosure of contingent assets and liabilities in the consolidated financial statements and accompanying notes. Significant estimates in the Company’s consolidated financial statements relate to clinical trial accruals and the valuation of equity awards. Management evaluates its estimates on an ongoing basis. Although estimates are based on the Company’s historical experience, knowledge of current events, and actions it may undertake in the future, actual results may ultimately materially differ from these estimates and assumptions.
Concentration of Credit Risk and Off-Balance Sheet Risk	Concentration of Credit Risk and Off-Balance Sheet Risk Financial instruments which potentially subject the Company to significant concentration of credit risk consist of cash and cash equivalents and short-term investments. The Company maintains deposits in federally insured financial institutions in excess of federally insured limits. The Company has not experienced any losses in such accounts, and management believes that the Company is not exposed to significant credit risk due to the financial position of the depository institutions in which those deposits are held. The Company’s investment policy includes guidelines for the quality of the related institutions and financial instruments and defines allowable investments that the Company may invest in, which the Company believes minimizes the exposure to concentration of credit risk.
Comprehensive Loss	Comprehensive Loss The Company is required to report all components of comprehensive loss, including net loss, in the consolidated financial statements in the period in which they are recognized. Comprehensive loss is defined as the change in equity during a period from transactions and other events and circumstances from non-owner sources, including unrealized gains and losses on investments and foreign currency gains and losses. Other comprehensive (loss) income, net includes unrealized losses or gains on short-term investments as well as foreign currency translation losses or gains.
Cash and Cash Equivalents	Cash and Cash Equivalents Cash and cash equivalents include cash in readily available checking and savings accounts, and money market funds. The Company considers all highly liquid investments with an original maturity of three months or less from the date of purchase to be cash equivalents.
Short-Term Investments	Short-Term Investments Available-for-sale securities are carried at fair value, with the unrealized gains and losses reported in comprehensive loss . The amortized cost of available-for-sale debt securities is adjusted for amortization of premiums and accretion of discounts to maturity. Such amortization and accretion are included in interest income. Realized gains and losses and declines in value judged to be other-than-temporary, if any, on available-for-sale securities are included in other income or expense. The cost of securities sold is based on the specific identification method. Interest and dividends on securities classified as available-for-sale are included in interest income.
Prepaid Expenses and Other Current Assets	Prepaid Expenses and Other Current Assets Prepaid expenses and other current assets primarily represent amounts related to director and officer insurance, preclinical research and clinical trial agreements, equity issuance costs and an estimated tax refund for the year ended December 31, 2020 from the Australian Tax Office for eligible research and development expenditures.
Property and Equipment	Property and Equipment Property and equipment is stated at cost and depreciated using the straight-line method over the estimated useful lives of the assets (generally three to five years).
Impairment of Long-Lived Assets	Impairment of Long-Lived Assets Long-lived assets consist primarily of property and equipment. An impairment loss is recorded if and when events and circumstances indicate that assets might be impaired and the undiscounted cash flows estimated to be generated by those assets are less than the carrying amount of those assets. While the Company’s current and historical operating losses and negative cash flows are indicators of impairment, management believes that future cash flows to be received support the carrying value of its long-lived assets and, accordingly, has not recognized any impairment losses since inception.
Accrued Research and Development Expense	Accrued Research and Development Expense The Company is required to estimate its expenses resulting from its obligations under contracts with vendors, consultants and contract research organizations, in connection with conducting research and development activities. The financial terms of these contracts are subject to negotiations, which vary from contract to contract and may result in payment flows that do not match the periods over which materials or services are provided under such contracts. The Company reflects research and development expenses in its consolidated financial statements by matching those expenses with the period in which services and efforts are expended. The Company accounts for these expenses according to the progress of the preclinical or clinical study as measured by the timing of various aspects of the study or related activities. The Company determines accrual estimates through review of the underlying contracts along with preparation of financial models taking into account discussions with research and other key personnel as to the progress of studies, or other services being conducted. During the course of a study, the Company adjusts its rate of expense recognition if actual results differ from its estimates. The Company classifies its estimates for accrued research and development expenses as accrued expenses on the accompanying consolidated balance sheet.
Australian Research and Development Tax Incentive	Australian Research and Development Tax Incentive The Company is eligible under the Australian Research and Development Tax Incentive Program, or the Tax Incentive, to obtain a cash refund from the Australian Taxation Office for eligible research and development expenditures. To be eligible, the Company must have revenue of less than AUD $20.0 million during the reimbursable period and cannot be controlled by income tax exempt entities. The Tax Incentive is recognized as a reduction to research and development expense when there is reasonable assurance that the Tax Incentive will be received, the relevant expenditure has been incurred, and the amount can be reliably measured. The Company classifies its estimate for the Tax Incentive as prepaid expenses and other current assets on the accompanying consolidated balance sheet.
Research and Development	Research and Development Research and development expenses include salaries and related overhead expenses, non-cash stock-based compensation expense, external research and development expenses incurred under arrangements with third parties, costs of services performed by consultants and contract research organizations, and regulatory costs including those related to preparing and filing INDs with the FDA. Research and development costs are expensed as incurred.
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 consolidated statement of operations.
Stock-Based Compensation	Stock-based Compensation The Company measures employee and nonemployee stock-based awards, including stock options and purchase rights, at grant-date fair value and records compensation expense on a straight-line basis over the vesting period of the award. The Company uses the Black-Scholes option pricing model to value its stock option awards. Estimating the fair value of stock option awards requires management to apply judgment and make estimates of certain assumptions, including the volatility of the Company’s common stock, the expected term of the Company’s stock options, the expected dividend yield and the fair value of the Company’s common stock on the measurement date. As a result, if factors change and management uses different assumptions, stock-based compensation expense could be materially different for future awards.
Income Tax	Income Taxes The Company accounts for income taxes under the asset and liability method, which requires the recognition of deferred tax assets and liabilities for the expected future tax consequences of events that have been included in the consolidated financial statements. Under this method, deferred tax assets and liabilities are determined on the basis of the differences between the consolidated financial statements and tax basis of assets and liabilities using enacted tax rates in effect for the year in which the differences are expected to reverse. The effect of a change in tax rates on deferred tax assets and liabilities is recognized in income in the period that includes the enactment date. The Company recognizes deferred tax assets to the extent that the Company believes these assets are more likely than not to be realized. In making such a determination, management considers all available positive and negative evidence, including future reversals of existing taxable temporary differences, projected future taxable income, tax-planning strategies, and results of recent operations. If management determines that the Company would be able to realize its deferred tax assets in the future in excess of their net recorded amount, management would make an adjustment to the deferred tax asset valuation allowance, which would reduce the provision for income taxes. The Company records uncertain tax positions on the basis of a two-step process whereby (1) management determines whether it is more likely than not that the tax positions will be sustained on the basis of the technical merits of the position and (2) for those tax positions that meet the more- likely-than-not recognition threshold, management recognizes the largest amount of tax benefit that is more than 50 percent likely to be realized upon ultimate settlement with the related tax authority. The Company recognizes interest and penalties related to unrecognized tax benefits within income tax expense. Any accrued interest and penalties are included within the related tax liability.
Net Loss per Share	Net Loss per Share Basic net loss per share is calculated by dividing the net loss by the weighted-average number of common shares outstanding for the period. Diluted net loss per share is computed by dividing the net loss by the weighted average number of common shares and common share equivalents outstanding for the period. Common stock equivalents are only included when their effect is dilutive. The Company’s potentially dilutive securities include outstanding options under the Company’s equity incentive plan and outstanding warrants to purchase common stock, each of which have been excluded from the computation of diluted net loss per share as they would be anti-dilutive to the net loss per share. 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. Potentially dilutive securities not included in the calculation of diluted net loss per share attributable to common stockholders because to do so would be anti-dilutive are as follows (in common stock equivalent shares): Year Ended December 31, Year Ended December 31, 2020 2019 Common stock options 2,463,317 1,821,093 Common stock warrants 80,428 80,428 Total 2,543,745 1,901,521

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2020
Accounting Policies [Abstract]
Summary of Potentially Dilutive Securities Not Included in Calculation of Diluted Net Loss Per Share	Potentially dilutive securities not included in the calculation of diluted net loss per share attributable to common stockholders because to do so would be anti-dilutive are as follows (in common stock equivalent shares): Year Ended December 31, Year Ended December 31, 2020 2019 Common stock options 2,463,317 1,821,093 Common stock warrants 80,428 80,428 Total 2,543,745 1,901,521

Fair Value of Financial Instr_2

Fair Value of Financial Instruments (Tables)	12 Months Ended
	Dec. 31, 2020
Fair Value Disclosures [Abstract]
Summary of Assets that Require Fair Value Measurements on Recurring Basis and Their Respective Input Levels Based on Fair Value Hierarchy	The following tables summarize the Company’s assets that require fair value measurements on a recurring basis and their respective input levels based on the fair value hierarchy (in thousands): Fair Value Measurements Using Quoted Prices in Significant Significant Active Markets Other Unobservable December 31, for Identical Observable Inputs 2020 Assets (Level 1) Inputs (Level 2) (Level 3) Short-term investments: U.S. treasury securities $ 56,220 $ 56,220 $ - $ - Certificates of deposit 1,961 1,961 - - Total $ 58,181 $ 58,181 $ - $ - Fair Value Measurements Using Quoted Prices in Significant Significant Active Markets Other Unobservable December 31, for Identical Observable Inputs 2019 Assets (Level 1) Inputs (Level 2) (Level 3) Short-term investments: U.S. treasury securities $ 28,549 $ 28,549 $ - $ - Agency securities 5,994 - 5,994 - Certificates of deposit 5,381 5,381 - - Total $ 39,924 $ 33,930 $ 5,994 $ -

Short-Term Investments (Tables)

Short-Term Investments (Tables)	12 Months Ended
	Dec. 31, 2020
Investments Debt And Equity Securities [Abstract]
Schedule of Company's Short-Term Investments	The following table summarizes the Company’s short-term investments (in thousands): Maturity Amortized Unrealized Unrealized Estimated (in years) Cost Gains Losses Fair Value December 31, 2020 U.S. treasury securities 1 or less $ 56,218 $ 6 $ (4 ) $ 56,220 Certificates of deposit 1 or less 1,955 6 - 1,961 Total $ 58,173 $ 12 $ (4 ) $ 58,181 December 31, 2019 U.S. treasury securities 1 or less $ 23,513 $ 6 $ (4 ) $ 23,515 U.S. treasury securities >1 and <5 5,035 - (1 ) 5,034 Agency securities 1 or less 5,976 19 (1 ) 5,994 Certificates of deposit 1 or less 4,131 22 - 4,153 Certificates of deposit >1 and <5 1,220 8 - 1,228 Total $ 39,875 $ 55 $ (6 ) $ 39,924

Property and Equipment (Tables)

Property and Equipment (Tables)	12 Months Ended
	Dec. 31, 2020
Property Plant And Equipment [Abstract]
Schedule of Property and Equipment	Property and equipment consisted of the following (in thousands): December 31, December 31, 2020 2019 Furniture & fixtures $ 60 $ 60 Machinery & lab equipment 211 24 Computer equipment 42 38 Less accumulated depreciation and amortization (74 ) (29 ) Property and equipment, net $ 239 $ 93

Accrued Expenses (Tables)

Accrued Expenses (Tables)	12 Months Ended
	Dec. 31, 2020
Accrued Liabilities Current [Abstract]
Schedule of Accrued Expenses	Accrued expenses consisted of the following (in thousands): December 31, December 31, 2020 2019 Accrued payroll and other employee benefits $ 1,870 $ 1,215 Clinical studies 493 442 Other accruals 307 267 Preclinical studies 72 15 Accrued interest 71 71 Total accrued expenses $ 2,813 $ 2,010

Notes Payable (Tables)

Notes Payable (Tables)	12 Months Ended
	Dec. 31, 2020
Debt Disclosure [Abstract]
Schedule of Aggregate Carrying Amounts of Term Loans	The aggregate carrying amounts of the Term Loans are comprised of the following (in thousands): December 31, December 31, 2020 2019 Principal $ 10,000 $ 10,000 Add: accreted liability for final payment fee 176 35 Less: unamortized discount (235 ) (354 ) Total $ 9,941 $ 9,681
Schedule Future Maturities of Term Loans, Including Final Payment Fee	Future maturities of the Term Loans, including the Final Payment fee, as of December 31, 2020 were as follows (in thousands): December 31, 2020 Year ending December 31, 2021 $ 1,667 Year ending December 31, 2022 3,333 Year ending December 31, 2023 3,333 Year ending December 31, 2024 2,117 10,450 Unaccreted balance for Final Payment fee on Term Loans (274 ) Unamortized discounts (235 ) 9,941 Less current portion (1,666 ) Noncurrent portion $ 8,275

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	12 Months Ended
	Dec. 31, 2020
Equity [Abstract]
Summary of Stock Option Activity	The following summarizes stock option activity for the year ended December 31, 2020: Outstanding Options Weighted- Average Exercise Price Per Share Weighted Average Remaining Contractual Term (in years) Aggregate Intrinsic Value (in thousands) (a) Balances as of December 31, 2019 1,821,093 $ 5.64 9.24 $ 17 Granted 852,368 $ 4.29 Exercised (3,000 ) $ 2.45 Forfeitures and cancellations (207,144 ) $ 2.45 Balances as of December 31, 2020 (b) 2,463,317 $ 3.71 7.98 $ 4,726 Options exercisable as of December 31, 2020 (b) 1,041,624 $ 3.52 6.91 $ 2,177 (a) Aggregate intrinsic value in this table was calculated as the positive difference, if any, between the closing price per share of the Company’s common stock on December 31, 2020 of $5.35 and the price of the underlying options. (b) The weighted-average exercise price per share of the options outstanding and exercisable as of December 31, 2020 includes the impact of the repricing of 1,475,093 options on April 22, 2020 at $2.45 per share.
Summary of Non-cash Stock-based Compensation Expense	Total non-cash stock-based compensation expense for all stock awards and purchase rights, net of forfeitures recognized as they occur, that was recognized in the consolidated statement of operations is as follows (in thousands): Year Ended December 31, Year Ended December 31, 2020 2019 Research and development $ 1,773 $ 1,207 General and administrative 2,044 1,045 Total $ 3,817 $ 2,252
Summary of Weighted-Average Assumptions Used to Determine Fair Value of Stock Option Grants	The weighted-average assumptions used in the Black-Scholes option pricing model to determine the fair value of the employee and nonemployee stock option grants were as follows: Year Ended December 31, Year Ended December 31, 2020 2019 Risk-free interest rate 0.65% 2.23% Expected volatility 89.56% 93.58% Expected term (in years) 5.77 5.77 Expected dividend yield 0% 0%
Summary of Reserved Shares of Common Stock for Future Issuance	Common stock reserved for future issuance consists of the following as of December 31, 2020 and 2019: December 31, December 31, 2020 2019 Stock options issued and outstanding 2,463,317 1,821,093 Warrants for common stock 80,428 80,428 Awards available under the 2018 Equity Incentive Plan 1,039,531 813,473 Employee stock purchase plan 612,529 503,716 Total 4,195,805 3,218,710

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2020
Commitments And Contingencies Disclosure [Abstract]
Future Minimum Lease Payments Required Under Non-Cancelable Leases	The future minimum lease payments required under non-cancelable leases as of December 31, 2020, are summarized as follows (in thousands): Years Ending December 31, 2021 $ 153 2022 26 Total $ 179

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Summary of Components of Loss Before Income Tax Provision (Benefit)	The components of loss before income tax provision (benefit) for the years ended December 31, 2020 and 2019 consisted of the following (in thousands): Year Ended December 31, Year Ended December 31, 2020 2019 U.S. (29,420 ) (23,167 ) Foreign (393 ) (2,433 ) $ (29,813 ) $ (25,600 )
Summary of Reconciliation of Expected Statutory Federal Income Tax Provision to Actual Income Tax Provision	The following is a reconciliation of the expected statutory federal income tax provision to our actual income tax provision for the years ended December 31, 2020 and 2019 (in thousands): Year Ended December 31, Year Ended December 31, 2020 2019 Income taxes at statutory rates $ (6,261 ) $ (5,376 ) State income tax, net of federal benefit - 1 Stock-based compensation 97 276 Permanent items 15 54 Federal research and orphan drug credits (445 ) (684 ) Foreign rate differential 367 (158 ) Change in federal valuation allowance 6,227 5,887 $ - $ -
Significant Components of Deferred Tax Assets and Liabilities	The tax effects of temporary differences that give rise to significant portions of the deferred tax assets and deferred tax liabilities as of December 31, 2020 and 2019 are as follows (in thousands): December 31, December 31, 2020 2019 Deferred tax assets: Net operating loss carryforward $ 12,338 $ 7,212 Credits 1,940 1,227 Intangibles 118 129 Equity compensation 888 188 Other 286 221 Total deferred tax assets 15,570 8,977 Valuation allowance (15,564 ) (8,976 ) Total deferred tax assets, net of allowance $ 6 $ 1 Deferred tax liabilities: Other (6 ) (1 ) Total deferred tax liabilities $ (6 ) $ (1 ) Net deferred taxes $ - $ -
Summary of Reconciliation of Unrecognized Tax Benefits	The following table summarizes the reconciliation of the unrecognized tax benefits activity during the years ended December 31, 2020 and 2019 (in thousands): Year Ended December 31, Year Ended December 31, 2020 2019 Unrecognized tax benefits – beginning $ 360 $ 89 Gross increases – tax positions in prior period 1,988 - Gross decreases – tax positions in prior period - - Gross increase – current-period tax positions 319 271 Gross decrease – current-period tax positions - - Settlements - - Lapse of statute of limitations - - Unrecognized tax benefits – ending $ 2,667 $ 360

Selected Quarterly Financial _2

Selected Quarterly Financial Data (unaudited) (Tables)	12 Months Ended
	Dec. 31, 2020
Quarterly Financial Information Disclosure [Abstract]
Selected Quarterly Financial Data (unaudited)	The operating results for any quarter are not necessarily indicative of results for any future period. in thousands (except per share amounts) First Quarter Second Quarter Third Quarter Fourth Quarter Year Ended December 31, 2020 Operating expenses $ 7,452 $ 6,610 $ 6,516 $ 8,970 Net loss (7,837 ) (6,461 ) (6,597 ) (8,918 ) Net loss per common share, basic and diluted $ (0.45 ) $ (0.37 ) $ (0.31 ) $ (0.36 ) Year Ended December 31, 2019 Operating expenses $ 6,348 $ 6,439 $ 6,324 $ 7,616 Net loss (5,950 ) (6,069 ) (6,014 ) (7,567 ) Net loss per common share, basic and diluted $ (0.34 ) $ (0.35 ) $ (0.35 ) $ (0.44 )

Organization and Accounting P_2

Organization and Accounting Pronouncements - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Date of incorporation	Mar. 16, 2017
State of incorporation	DE
Cash, Cash equivalents and short-term investments	$ 82,200,000
Foreign currency transaction net realized and unrealized gains (losses)	$ 300,000	$ 15,000

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Additional Information (Details) $ in Millions	12 Months Ended
	Dec. 31, 2020USD ($)
Minimum
Summary Of Significant Accounting Policies [Line Items]
Property and equipment, useful lives	3 years
Percentage of tax benefit to be realized upon ultimate settlement with tax authority	50.00%
Maximum
Summary Of Significant Accounting Policies [Line Items]
Property and equipment, useful lives	5 years
Maximum | Australian Taxation Office | Australian Research and Development Tax Incentive Program
Summary Of Significant Accounting Policies [Line Items]
Revenue for availability of research and development tax incentive	$ 20

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Summary of Potentially Dilutive Securities Not Included in Calculation of Diluted Net Loss Per Share (Details) - shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities not included in calculation of diluted net loss per share	2,543,745	1,901,521
Common Stock Options
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities not included in calculation of diluted net loss per share	2,463,317	1,821,093
Common Stock Warrants
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities not included in calculation of diluted net loss per share	80,428	80,428

Fair Value of Financial Instr_3

Fair Value of Financial Instruments - Summary of Assets that Require Fair Value Measurements on Recurring Basis and Their Respective Input Levels Based on Fair Value Hierarchy (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total short-term investments	$ 58,181	$ 39,924
U.S. Treasury Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total short-term investments	56,220	28,549
Certificates of Deposit
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total short-term investments	1,961	5,381
Agency Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total short-term investments		5,994
Level 1
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total short-term investments	58,181	33,930
Level 1 | U.S. Treasury Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total short-term investments	56,220	28,549
Level 1 | Certificates of Deposit
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total short-term investments	$ 1,961	5,381
Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total short-term investments		5,994
Level 2 | Agency Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total short-term investments		$ 5,994

Fair Value of Financial Instr_4

Fair Value of Financial Instruments - Additional Information (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Carrying amount of notes payable	$ 9.9	$ 9.7
Fair Value Measured Using Net Asset Value | Money Market Funds
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Investments in money market funds	$ 17.4	$ 10.3

Short-Term Investments - Schedu

Short-Term Investments - Schedule of Company's Short-Term Investments (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	$ 58,173	$ 39,875
Unrealized Gains	12	55
Unrealized losses	(4)	(6)
Short-term investments	58,181	39,924
U.S. Treasury Securities Maturing in One Year or Less
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	56,218	23,513
Unrealized Gains	6	6
Unrealized losses	(4)	(4)
Short-term investments	$ 56,220	$ 23,515
U.S. Treasury Securities Maturing in One Year or Less | Maximum
Schedule Of Available For Sale Securities [Line Items]
Maturity (in years)	1 year	1 year
U.S. Treasury Securities Maturing between One and Five years
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost		$ 5,035
Unrealized losses		(1)
Short-term investments		$ 5,034
U.S. Treasury Securities Maturing between One and Five years | Minimum
Schedule Of Available For Sale Securities [Line Items]
Maturity (in years)		1 year
U.S. Treasury Securities Maturing between One and Five years | Maximum
Schedule Of Available For Sale Securities [Line Items]
Maturity (in years)		5 years
Agency Securities Maturing in One Year or Less
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost		$ 5,976
Unrealized Gains		19
Unrealized losses		(1)
Short-term investments		$ 5,994
Agency Securities Maturing in One Year or Less | Maximum
Schedule Of Available For Sale Securities [Line Items]
Maturity (in years)		1 year
Certificates of Deposit Maturing in One Year or Less
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	$ 1,955	$ 4,131
Unrealized Gains	6	22
Short-term investments	$ 1,961	$ 4,153
Certificates of Deposit Maturing in One Year or Less | Maximum
Schedule Of Available For Sale Securities [Line Items]
Maturity (in years)	1 year	1 year
Certificates of Deposit Maturing between One and Five Years
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost		$ 1,220
Unrealized Gains		8
Short-term investments		$ 1,228
Certificates of Deposit Maturing between One and Five Years | Minimum
Schedule Of Available For Sale Securities [Line Items]
Maturity (in years)		1 year
Certificates of Deposit Maturing between One and Five Years | Maximum
Schedule Of Available For Sale Securities [Line Items]
Maturity (in years)		5 years

Short-Term Investments - Additi

Short-Term Investments - Additional information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Schedule Of Available For Sale Securities [Line Items]
Other than temporary impairment loss investments available for sale securities		$ 0
Minimum
Schedule Of Available For Sale Securities [Line Items]
Available for sale Securities debt maturities period	1 year
Maximum
Schedule Of Available For Sale Securities [Line Items]
Available for sale Securities debt maturities period	2 years

Property and Equipment - Schedu

Property and Equipment - Schedule of Property and Equipment (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Property Plant And Equipment [Line Items]
Less accumulated depreciation and amortization	$ (74)	$ (29)
Property and equipment, net	239	93
Furniture And Fixtures
Property Plant And Equipment [Line Items]
Property and equipment, gross	60	60
Machinery & Lab Equipment
Property Plant And Equipment [Line Items]
Property and equipment, gross	211	24
Computer Equipment
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 42	$ 38

Property and Equipment - Additi

Property and Equipment - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Property Plant And Equipment [Abstract]
Depreciation expense	$ 45,000	$ 23,000
Disposal of property and equipment	$ 0	$ 0

Accrued Expenses - Schedule of

Accrued Expenses - Schedule of Accrued Expenses (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Accrued Liabilities Current [Abstract]
Accrued payroll and other employee benefits	$ 1,870	$ 1,215
Clinical studies	493	442
Other accruals	307	267
Preclinical studies	72	15
Accrued interest	71	71
Total accrued expenses	$ 2,813	$ 2,010

Collaboration And License Agr_2

Collaboration And License Agreements - Additional Information (Details) - Biocon - USD ($)	1 Months Ended	31 Months Ended
	May 31, 2017	Nov. 30, 2019
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Common stock shares issued		2,316,134
Collaboration and License Agreement | Maximum
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Regulatory milestone payments	$ 30,000,000
Sales milestone payments	$ 565,000,000

Notes Payable - Additional Info

Notes Payable - Additional Information (Details) $ / shares in Units, $ in Millions	1 Months Ended
	Sep. 30, 2019USD ($)YearInstallment$ / sharesshares	Dec. 31, 2020USD ($)
Short Term Debt [Line Items]
Term Loan maturity date	Jun. 1, 2024
Fair value of the warrants at the date of issuance	$ 0.3
Expected Term
Short Term Debt [Line Items]
Warrants and rights outstanding, measurement input | Year	10
Volatility
Short Term Debt [Line Items]
Warrants and rights outstanding, measurement input	92.78
Risk Free Rate
Short Term Debt [Line Items]
Warrants and rights outstanding, measurement input	1.68
Expected Dividend
Short Term Debt [Line Items]
Warrants and rights outstanding, measurement input	0
Line of Credit
Short Term Debt [Line Items]
Debt instrument, frequency of periodic payment	monthly
Debt instrument, interest rate, basis for effective rate	prime rate
Percentage of final principal payment	4.50%
Required notice period for debt prepayment	30 days
Debt prepayment fee as percent on year one	3.00%
Debt prepayment fee as percent on year two	2.00%
Debt prepayment fee as percent from year three	1.00%
Debt issuance costs	$ 0.1
Debt instrument, interest rate, effective percentage	10.97%
Line of Credit | Prime Rate
Short Term Debt [Line Items]
Debt instrument, basis spread on variable rate	3.00%
Line of Credit | Minimum
Short Term Debt [Line Items]
Debt instrument, interest rate, stated percentage	8.25%
Loan Agreement
Short Term Debt [Line Items]
Borrowing capacity under loan agreement	$ 20
Additional funding not eligible		$ 10
Term A Loan
Short Term Debt [Line Items]
Borrowings under loan agreement	$ 10
Line of credit facility frequency of payments principal and interest | Installment	36
Lenders warrants exercisable for shares | shares	80,428
Warrants exercisable, per share exercise price | $ / shares	$ 3.73
Term B Loan
Short Term Debt [Line Items]
Borrowing capacity under loan agreement	$ 5
Percentage of lenders additional warrants to purchase shares of company's common stock	3.00%
Term C Loan
Short Term Debt [Line Items]
Borrowing capacity under loan agreement	$ 5
Percentage of lenders additional warrants to purchase shares of company's common stock	3.00%
Term A Loan & Term B Loan
Short Term Debt [Line Items]
Line of credit facility frequency of payments principal and interest | Installment	30

Notes Payable - Schedule of Agg

Notes Payable - Schedule of Aggregate Carrying Amounts of Term Loans (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Less: unamortized discount	$ (235)
Total	9,941
Line of Credit
Debt Instrument [Line Items]
Principal	10,000	$ 10,000
Add: accreted liability for final payment fee	176	35
Less: unamortized discount	(235)	(354)
Total	$ 9,941	$ 9,681

Notes Payable - Schedule Future

Notes Payable - Schedule Future Maturities of Term Loans, Including Final Payment Fee (Details) $ in Thousands	Dec. 31, 2020USD ($)
Debt Disclosure [Abstract]
Year ending December 31, 2021	$ 1,667
Year ending December 31, 2022	3,333
Year ending December 31, 2023	3,333
Year ending December 31, 2024	2,117
Debt instrument carrying amount including unaccreted liability for final payment fee	10,450
Unaccreted balance for Final Payment fee on Term Loans	(274)
Less: unamortized discount	(235)
Total	9,941
Less current portion	(1,666)
Noncurrent portion	$ 8,275

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Details)	Jul. 14, 2020USD ($)	May 28, 2020Directorshares	Apr. 22, 2020$ / sharesshares	Nov. 30, 2020	Aug. 31, 2020USD ($)$ / sharesshares	Mar. 31, 2020USD ($)shares	Oct. 31, 2018shares	Mar. 24, 2021shares	Dec. 31, 2020USD ($)$ / sharesshares	Dec. 31, 2019USD ($)$ / sharesshares	Dec. 31, 2020USD ($)$ / sharesshares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock, shares authorized | shares									200,000,000	200,000,000	200,000,000
Common stock, par value | $ / shares									$ 0.0001	$ 0.0001	$ 0.0001
Preferred stock, shares authorized | shares									10,000,000		10,000,000
Preferred stock, par value | $ / shares									$ 0.0001		$ 0.0001
Common stock, shares outstanding | shares									24,753,102	17,425,654	24,753,102
Number of shares available for issuance | shares									4,195,805	3,218,710	4,195,805
Repricing of outstanding options | shares			1,475,093
Stock-based compensation expense									$ 3,817,000	$ 2,252,000
Aggregate intrinsic value of stock options exercised									9,000	0
Proceeds from exercise of stock options									7,000	69,000
Fair value of stock options vested									$ 4,100,000	$ 1,400,000
Weighted-average grant-date fair value of options granted | $ / shares									$ 3.11	$ 4.65
Unrecognized compensation expense related to unvested stock options									$ 6,600,000		$ 6,600,000
Expected recognition period of unrecognized compensation expense									2 years 3 months 18 days
Number of non-management directors | Director		2
Dividends paid									$ 0
Executive Chairman, Chief Executive Officer and Non-management Directors
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Retention stock options issued to purchase common shares | shares		169,368
Executive Chairman
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Reduction in cash remuneration expressed as a percentage		65.00%
Chief Executive Officer
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Reduction in cash remuneration expressed as a percentage		85.00%
Non-Management Directors
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Reduction in cash remuneration expressed as a percentage		100.00%
Repricing of Outstanding Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unamortized stock-based compensation incremental expense on the repriced options									400,000
Stock-based compensation expense									200,000
Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Exercise price of options per share | $ / shares			$ 2.45
Follow-on Offering
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Proceeds from issuance of common stock									35,717,000
Open Market Sales Agreement | 2019 ATM Facility
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Commission rate				3.00%
Stock Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Repricing of outstanding options | shares			1,475,093
Exercise price of options per share | $ / shares			$ 2.45
Stock-based compensation expense									$ 400,000
Common Stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Issuance of common stock, Shares | shares									83,662
Common Stock | Follow-on Offering
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Issuance of common stock, Shares | shares					5,461,169
Sale of stock, price per share | $ / shares					$ 7
Gross proceeds from issuance of common stock					$ 38,200,000
Proceeds from issuance of common stock					$ 35,700,000
Common Stock | Over Allotment Option
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Issuance of common stock, Shares | shares					461,169
Common Stock | Open Market Sales Agreement | 2019 ATM Facility
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Issuance of common stock, Shares | shares									925,489	18,250
Gross proceeds from issuance of common stock									$ 8,400,000
Proceeds from issuance of common stock									8,100,000	$ (200,000)
Common stock shares maximum aggregate offering price									8,450,000
Stock issuance costs									$ 300,000
Common Stock | Open Market Sales Agreement | 2020 ATM Facility
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Issuance of common stock, Shares | shares									788,685
Gross proceeds from issuance of common stock									$ 10,400,000
Proceeds from issuance of common stock									10,000,000
Common stock shares maximum aggregate offering price	$ 150,000,000
Stock issuance costs									$ 400,000
Common Stock | Purchase Agreement | Lincoln Park Capital Fund, LLC
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Issuance of common stock, Shares | shares						65,374
Stock issuance costs						$ 400,000
Estimated maximum amount of common stock issuable						$ 15,000,000
Term of purchase agreement						36 months
Fair market value of commitment shares						$ 200,000
Common Stock | Subsequent Event | Open Market Sales Agreement | 2020 ATM Facility
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Issuance of common stock, Shares | shares								0
Common Stock | Subsequent Event | Purchase Agreement | Lincoln Park Capital Fund, LLC
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Issuance of common stock, Shares | shares								0
2018 Equity Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Equity incentive plan description									The number of shares of common stock reserved for issuance under the 2018 Plan will automatically increase on January 1 of each calendar year through January 1, 2028, in an amount equal to 5.0% of the total number of shares of the Company’s capital stock outstanding on the last day of the calendar month before the date of each automatic increase, or a lesser number of shares determined by the Board.
Repricing of outstanding options | shares									2,463,317	1,821,093	2,463,317
Exercise price of options per share | $ / shares									$ 2.45
Retention stock options issued to purchase common shares | shares									852,368
2018 Equity Incentive Plan | Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares available for issuance | shares									1,039,531		1,039,531
2018 Equity Incentive Plan | Common Stock Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Minimum options exercise price as percentage of fair market value of common stock									100.00%
Remaining vesting period									3 years
2018 Equity Incentive Plan | Common Stock Options | Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Award expiration period									10 years
2018 Equity Incentive Plan | Tranche One | Common Stock Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting percentage									25.00%
2017 Equity Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unvested shares issued under early exercise which are subject to repurchase | shares									153,690	265,232	153,690
Unvested stock liability									$ 100,000	$ 200,000	$ 100,000
2017 Equity Incentive Plan | Short Term Portion Of Unvested Stock Liability
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unvested stock liability									72,000		72,000
2017 Equity Incentive Plan | Long Term Portion Of Unvested Stock Liability
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unvested stock liability									$ 53,000		$ 53,000
2018 Employee Stock Purchase Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares authorized for issuance under purchase rights granted to employees | shares							343,275
Employee stock purchase plan description									Equity Stock Purchase Plan (ESPP) whereby eligible employees may elect to withhold up to 15% of their earnings to purchase shares of the Company’s common stock at a price per share equal to the lower of (i) 85% of the fair market value of a share of the Company’s common stock on the first date of an offering or (ii) 85% of the fair market value of a share of the Company’s common stock on the date of the purchase right (purchase right). Initially, 343,275 shares of the Company’s common stock were approved for issuance under the ESPP pursuant to purchase rights granted to the Company’s employees or to employees of any of the Company’s designated affiliates. The number of shares of the Company’s common stock reserved for issuance will automatically increase on January 1 of each calendar year through January 1, 2028, by the lesser of (1) 1.0% of the total number of shares of the Company’s common stock outstanding on the last day of the calendar month before the date of the automatic increase, and (2) 343,275 shares; provided that before the date of any such increase, the Board may determine that such increase will be less than the amount set forth in clauses (1) and (2)
Withhold Percentage of employees earnings to purchase shares of common stock							15.00%
Number of shares issued | shares									65,443		78,764
Number of shares available for future issuance under employee stock purchase plan | shares									612,529
2018 Employee Stock Purchase Plan | IPO
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Minimum stock price per share as percentage of fair market value of common stock							85.00%
2018 Employee Stock Purchase Plan | Purchase Right
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Minimum stock price per share as percentage of fair market value of common stock							85.00%

Stockholders' Equity - Summary

Stockholders' Equity - Summary of Stock Option Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	Apr. 22, 2020	Dec. 31, 2020	Dec. 31, 2019
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of Outstanding Options, Ending Balance	1,475,093
2018 Equity Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of Outstanding Options, Beginning Balance		1,821,093
Number of Outstanding Options, Granted		852,368
Number of Outstanding Options, Exercised		(3,000)
Number of Outstanding Options, Forfeitures and Cancellations		(207,144)
Number of Outstanding Options, Ending Balance		2,463,317	1,821,093
Number of Outstanding Options, Exercisable		1,041,624
Weighted- Average Exercise Price Per Share, Beginning Balance		$ 5.64
Weighted- Average Exercise Price Per Share, Granted		4.29
Exercise price of options per share		2.45
Weighted- Average Exercise Price Per Share, Forfeitures and Cancellations		2.45
Weighted- Average Exercise Price Per Share, Ending Balance		3.71	$ 5.64
Weighted- Average Exercise Price Per Share, Exercisable		$ 3.52
Weighted Average Remaining Contractual Term, Options Outstanding		7 years 11 months 23 days	9 years 2 months 26 days
Weighted Average Remaining Contractual Term, Options Exercisable		6 years 10 months 28 days
Aggregate Intrinsic Value, Options Outstanding		$ 4,726	$ 17
Aggregate Intrinsic Value, Options Exercisable		$ 2,177

Stockholders' Equity - Summar_2

Stockholders' Equity - Summary of Stock Option Activity (Parenthetical) (Details) - $ / shares	Apr. 22, 2020	Dec. 31, 2020
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Repricing of outstanding options	1,475,093
Stock Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Closing stock price per share		$ 5.35
Repricing of outstanding options	1,475,093
Exercise price of repriced options per share	$ 2.45

Stockholders' Equity - Summar_3

Stockholders' Equity - Summary of Total Non-cash Stock-based Compensation Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total non-cash stock-based compensation expense	$ 3,817	$ 2,252
Research and Development Expense
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total non-cash stock-based compensation expense	1,773	1,207
General and Administrative Expense
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total non-cash stock-based compensation expense	$ 2,044	$ 1,045

Stockholders' Equity - Summar_4

Stockholders' Equity - Summary of Weighted-Average Assumptions Used to Determine Fair Value of Stock Option Grants (Details)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Equity [Abstract]
Risk-free interest rate	0.65%	2.23%
Expected volatility	89.56%	93.58%
Expected term (in years)	5 years 9 months 7 days	5 years 9 months 7 days
Expected dividend yield	0.00%	0.00%

Stockholders' Equity - Summar_5

Stockholders' Equity - Summary of Common Stock Reserved for Future Issuance (Details) - shares	Dec. 31, 2020	Dec. 31, 2019
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total common stock reserved for future issuance	4,195,805	3,218,710
Stock Options Issued and Outstanding
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total common stock reserved for future issuance	2,463,317	1,821,093
Warrants for Common Stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total common stock reserved for future issuance	80,428	80,428
Awards Available Under 2018 Equity Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total common stock reserved for future issuance	1,039,531	813,473
Employee Stock Purchase Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total common stock reserved for future issuance	612,529	503,716

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Commitments and Contingencies [Line Items]
Rent expense of operating lease	$ 200,000	$ 200,000
Litigation expense	$ 0
La Jolla and South San Francisco
Commitments and Contingencies [Line Items]
Non-cancelable operating lease, expiration	2022-02

Commitments and Contingencies_2

Commitments and Contingencies - Future Minimum Lease Payments Required Under Non-Cancelable Leases (Details) $ in Thousands	Dec. 31, 2020USD ($)
Commitments And Contingencies Disclosure [Abstract]
2021	$ 153
2022	26
Total	$ 179

Income Taxes - Summary of Compo

Income Taxes - Summary of Components of Loss Before Income Tax Provision (Benefit) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Income Tax Disclosure [Abstract]
U.S.	$ (29,420)	$ (23,167)
Foreign	(393)	(2,433)
Loss before income tax provision (benefit)	$ (29,813)	$ (25,600)

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Tax Credit Carryforward [Line Items]
Current income tax expense (benefit)	$ 0	$ 0
Deferred income tax expense (benefit)	0	0
Deferred tax assets, Valuation allowance	15,564,000	8,976,000
Increase in valuation allowance	$ 6,600,000
Federal and state net operating loss carry forwards, Expiration year	2037
Federal net operating loss carryover			$ 53,000,000
Operating loss carryforwards, Limitation of use	Federal net operating losses generated after December 31, 2017 carryover indefinitely and may generally be used to offset up to 80% of future taxable income.
Tax credit carry forwards	$ 1,940,000	$ 1,227,000
Tax credit carryforward, Expiration year	2037
Cumulative change in ownership percentage	50.00%
Cumulative change in ownership period	3 years
Carryback period of certain losses extension period	5 years
Suspension of limitation imposed by tax cuts and jobs act, percent	80.00%	80.00%	80.00%
Maximum
Tax Credit Carryforward [Line Items]
Operating loss carryforwards limitation rate on taxable income	80.00%
Percentage of interest expense deducted	50.00%
Minimum
Tax Credit Carryforward [Line Items]
Percentage of interest expense deducted	30.00%
Federal
Tax Credit Carryforward [Line Items]
Federal tax loss carry forwards	$ 53,900,000
Tax credit carry forwards	1,400,000
State
Tax Credit Carryforward [Line Items]
Tax credit carry forwards	600,000
California
Tax Credit Carryforward [Line Items]
Foreign tax loss carry forwards	30,700,000
Australia
Tax Credit Carryforward [Line Items]
Federal net operating loss carryover	$ 1,900,000

Income Taxes - Reconciliation o

Income Taxes - Reconciliation of Expected Statutory Federal Income Tax Provision to Actual Income Tax Provision (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Income Tax Expense Benefit Continuing Operations Income Tax Reconciliation [Abstract]
Income taxes at statutory rates	$ (6,261)	$ (5,376)
State income tax, net of federal benefit		1
Stock-based compensation	97	276
Permanent items	15	54
Federal research and orphan drug credits	(445)	(684)
Foreign rate differential	367	(158)
Change in federal valuation allowance	$ 6,227	$ 5,887

Income Taxes - Summary of Net D

Income Taxes - Summary of Net Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Deferred tax assets:
Net operating loss carryforward	$ 12,338	$ 7,212
Credits	1,940	1,227
Intangibles	118	129
Equity compensation	888	188
Other	286	221
Total deferred tax assets	15,570	8,977
Valuation allowance	(15,564)	(8,976)
Total deferred tax assets, net of allowance	6	1
Deferred tax liabilities:
Other	(6)	(1)
Total deferred tax liabilities	(6)	(1)
Net deferred taxes	$ 0	$ 0

Income Taxes - Summary of Recon

Income Taxes - Summary of Reconciliation of Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Unrecognized tax benefits – beginning	$ 360	$ 89
Gross increases – tax positions in prior period	1,988
Gross increase – current-period tax positions	319	271
Unrecognized tax benefits – ending	$ 2,667	$ 360

Retirement Plan - Additional In

Retirement Plan - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Compensation And Retirement Disclosure [Abstract]
Employer's matching contributions to 401(k) plan	$ 0	$ 0

Selected Quarterly Financial _3

Selected Quarterly Financial Data (unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019
Quarterly Financial Information Disclosure [Abstract]
Operating expenses	$ 8,970	$ 6,516	$ 6,610	$ 7,452	$ 7,616	$ 6,324	$ 6,439	$ 6,348	$ 29,548	$ 26,727
Net loss	$ (8,918)	$ (6,597)	$ (6,461)	$ (7,837)	$ (7,567)	$ (6,014)	$ (6,069)	$ (5,950)	$ (29,813)	$ (25,600)
Net loss per share, basic and diluted	$ (0.36)	$ (0.31)	$ (0.37)	$ (0.45)	$ (0.44)	$ (0.35)	$ (0.35)	$ (0.34)	$ (1.46)	$ (1.47)

Subsequent Events - Additional

Subsequent Events - Additional Information (Details) $ / shares in Units, $ in Millions	Feb. 03, 2021USD ($)Investor$ / sharesshares	Dec. 31, 2020shares
Common Stock
Subsequent Event [Line Items]
Issuance of common stock, Shares		83,662
Subsequent Event | Securities Purchase Agreement | Offering
Subsequent Event [Line Items]
Number of institutional investors | Investor	2
Shares upon exercise of warrants	1,285,713
Gross proceeds from issuance of common stock | $	$ 30
Subsequent Event | Common Stock | Securities Purchase Agreement | Offering
Subsequent Event [Line Items]
Issuance of common stock, Shares	4,285,710
Subsequent Event | Common Stock Warrants | Securities Purchase Agreement
Subsequent Event [Line Items]
Warrants exercisable, per share exercise price | $ / shares	$ 14
Sale of stock, price per share | $ / shares	$ 25
Subsequent Event | Common Stock Warrants | Securities Purchase Agreement | Minimum
Subsequent Event [Line Items]
Gross proceeds from issuance of common stock | $	$ 25