Black Diamond Therapeutics (BDTX) 10-K 24 Mar 20 2019 FY Annual report Financial data

Cover Page

Cover Page - USD ($)	12 Months Ended
	Dec. 31, 2019	Mar. 16, 2020	Feb. 03, 2020
Cover page.
Document Type	10-K
Entity Registrant Name	BLACK DIAMOND THERAPEUTICS, INC.
Document Annual Report	true
Document Transition Report	false
Entity File Number	001-38501
Entity Central Index Key	0001701541
Document Period End Date	Dec. 31, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	FY
Current Fiscal Year End Date	--12-31
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	81-4254660
Title of 12(b) Security	Common stock, par value $0.0001
Trading Symbol	BDTX
Security Exchange Name	NASDAQ
Entity Well-known Seasoned Issuer	No
Entity Interactive Data Current	Yes
Entity Voluntary Filers	No
Entity Shell Company	false
Entity Current Reporting Status	Yes
Amendment Flag	false
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
Entity Address, Address Line One	139 Main Street
Entity Address, City or Town	Cambridge
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	02142
City Area Code	(617)
Local Phone Number	252-0848
Entity Public Float			$ 910,076,402
Entity Common Stock, Shares Outstanding		35,910,705
Documents Incorporated by Reference	None.

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($)	Dec. 31, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 154,666,000	$ 51,660,000
Prepaid expenses and other current assets	1,048,000	24,000
Total current assets	155,714,000	51,684,000
Equipment, net	164,000	134,000
Restricted cash	55,000	0
Deferred offering costs	2,303,000	0
Other non-current assets	59,000	8,000
Total assets	158,295,000	51,826,000
Current liabilities:
Accounts payable	1,964,000	416,000
Amounts due to related party	0	1,707,000
Accrued expenses and other current liabilities	2,899,000	452,000
Total current liabilities	4,863,000	2,575,000
Derivative liabilities	16,000	4,023,000
Total liabilities	4,879,000	6,598,000
Commitments and contingencies (Note 11)	0	0
Convertible preferred stock (series A, B and C); $0.0001 par value; 64,871,795 shares authorized at December 31, 2019 and 44,867,089 shares authorized at December 31, 2018; 64,839,353 shares issued and outstanding at December 31, 2019 and 33,668,075 shares issued and outstanding at December 31, 2018; aggregate liquidation preference of $194,727 at December 31, 2019 and $65,002 at December 31, 2018	200,573,000	60,770,000
Stockholders' equity (deficit):
Common stock; $0.0001 par value; 80,000,000 shares authorized at December 31, 2019 and 57,803,522 shares authorized at December 31, 2018; 2,236,672 shares issued and outstanding at December 31, 2019 and 2,173,684 shares issued and outstanding at December 31, 2018	1,000	1,000
Additional paid-in capital	3,812,000	169,000
Accumulated deficit	(50,970,000)	(15,712,000)
Total stockholders' equity (deficit)	(47,157,000)	(15,542,000)
Total liabilities, convertible preferred stock and stockholders' equity (deficit)	$ 158,295,000	$ 51,826,000

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Statement of Financial Position [Abstract]
Convertible preferred stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Convertible preferred stock, shares authorized	64,871,795	44,867,089
Convertible preferred stock, shares issued	64,839,353	33,668,075
Convertible preferred stock, shares outstanding	64,839,353	33,668,075
Convertible preferred stock, liquidation preference	$ 194,727	$ 65,002
Common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Common stock, shares authorized	80,000,000	57,803,522
Common stock, shares issued	2,236,672	2,173,684
Common stock, shares outstanding	2,236,672	2,173,684

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Operating expenses:
Research and development (inclusive of $9,966 and $2,403, respectively, with a related party)	$ 21,753	$ 6,950
General and administrative (inclusive of $445 and $325, respectively, with a related party)	7,579	1,954
Total operating expenses	29,332	8,904
Loss from operations	(29,332)	(8,904)
Other income (expense):
Interest income	461	4
Change in fair value of derivative liabilities	(6,393)	(15)
Other income (expense)	6	(16)
Total other income (expense), net	(5,926)	(27)
Net loss attributable to common stockholders	$ (35,258)	$ (8,931)
Net loss per share attributable to common stockholders, basic and diluted (in dollars per share)	$ (16.99)	$ (4.42)
Weighted average common shares outstanding, basic and diluted	2,075,753	2,018,623

Consolidated Statements of Op_2

Consolidated Statements of Operations (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Income Statement [Abstract]
Research and development, related party	$ 9,966	$ 2,403
General and administrative, related party	$ 445	$ 325

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Cash flows from operating activities:
Net loss	$ (35,258)	$ (8,931)
Adjustment to reconcile net loss to net cash used in operating activities:
Stock-based compensation expense	3,643	64
Change in fair value of derivative liabilities	6,393	15
Depreciation expense	47	44
Loss on disposal of property and equipment	38	0
Changes in current assets and liabilities:
Prepaid expenses and other current assets	(1,024)	12
Other non-current assets	(51)	(3)
Accounts payable	1,454	264
Amounts due to related party	(1,707)	(213)
Accrued expenses and other current liabilities	1,791	294
Net cash used in operating activities	(24,674)	(8,454)
Cash flows from investing activities:
Purchases of equipment	(21)	(76)
Net cash used in investing activities	(21)	(76)
Cash flows from financing activities:
Proceeds from issuance of convertible preferred stock, net	129,499	52,312
Payment of deferred offering costs	(1,743)	0
Net cash provided by financing activities	127,756	52,312
Net increase (decrease) in cash and cash equivalents	103,061	43,782
Cash, cash equivalents and restricted cash, beginning of year	51,660	7,878
Cash, cash equivalents and restricted cash, end of year	154,721	51,660
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents
Cash, cash equivalents and restricted cash, end of year	154,721	7,878
Supplemental disclosure of non-cash investing and financing activities:
Deferred offering and stock issuance costs included in accounts payable and accrued expenses and other current liabilities	656	0
Purchases of equipment included in accounts payable and accrued expenses	94	0
Series B
Supplemental disclosure of non-cash investing and financing activities:
Issuance of series B convertible preferred stock tranche right	0	4,000
Exercise of series B convertible preferred stock tranche right	$ 6,393	$ 0

Consolidated Statements of Conv

Consolidated Statements of Convertible Preferred Stock and Stockholders' Equity (Deficit) - USD ($) $ in Thousands	Total	Common stock	Additional paid-in capital	Accumulated deficit	Series A	Series B	Series C
Beginning balance (in shares) at Dec. 31, 2017	12,501,503
Beginning balance at Dec. 31, 2017	$ 12,458
Convertible preferred stock
Issuance of convertible preferred stock, net (in shares)					10,000,000	11,166,572
Issuance of convertible preferred stock, net					$ 9,899	$ 38,413
Ending balance (in shares) at Dec. 31, 2018	33,668,075				22,501,503	11,166,572
Ending balance at Dec. 31, 2018	$ 60,770				$ 22,357	$ 38,413
Beginning balance (in shares) at Dec. 31, 2017		2,081,187
Beginning balance at Dec. 31, 2017	(6,675)	$ 1	$ 105	$ (6,781)
Common stock
Grant of restricted common stock awards (in shares)		92,497
Grant of restricted common stock awards	0
Stock-based compensation	64		64
Net loss	$ (8,931)			(8,931)
Ending balance (in shares) at Dec. 31, 2018	2,173,684	2,173,684
Ending balance at Dec. 31, 2018	$ (15,542)	$ 1	169	(15,712)
Convertible preferred stock
Issuance of convertible preferred stock, net (in shares)						11,751,154	19,420,124
Issuance of convertible preferred stock, net						$ 55,066	$ 84,737
Ending balance (in shares) at Dec. 31, 2019	64,839,353				22,501,503	22,917,726	19,420,124
Ending balance at Dec. 31, 2019	$ 200,573				$ 22,357	$ 93,479	$ 84,737
Common stock
Grant of restricted common stock awards (in shares)		62,988
Grant of restricted common stock awards	0
Stock-based compensation	3,643		3,643
Net loss	$ (35,258)			(35,258)
Ending balance (in shares) at Dec. 31, 2019	2,236,672	2,236,672
Ending balance at Dec. 31, 2019	$ (47,157)	$ 1	$ 3,812	$ (50,970)

NATURE OF BUSINESS AND BASIS OF

NATURE OF BUSINESS AND BASIS OF PRESENTATION	12 Months Ended
	Dec. 31, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
NATURE OF BUSINESS AND BASIS OF PRESENTATION	NATURE OF BUSINESS AND BASIS OF PRESENTATION Black Diamond Therapeutics, Inc. (the “Company”) is a precision oncology medicine company pioneering the discovery and development of small molecule, tumor-agnostic therapies. The Company was originally organized as a limited liability company in December 2014 under the name ASET Therapeutics LLC. In September 2016 the Company was converted to a corporation under the laws of the State of Delaware under the name ASET Therapeutics, Inc. The Company changed its name to Black Diamond Therapeutics, Inc. in January 2018. Since its inception, the Company has devoted substantially all of its efforts to raising capital, obtaining financing, and incurring research and development costs related to the development of its mutation, allostery, and pharmacology computational and discovery platform. The Company is subject to risks and uncertainties common to early-stage companies in the biotechnology industry. There can be no assurance that the Company’s research and development will be successfully completed, that adequate protection for the Company’s technology will be obtained, that any products developed will obtain necessary government regulatory approval or that any products, if approved, will be commercially viable. The Company operates in an environment of rapid technological innovation and substantial competition from pharmaceutical and biotechnological companies. In addition, the Company is dependent upon the services of its employees, consultants and service providers including a related party Ridgeline Therapeutics GmbH (“Ridgeline”). Even if the Company’s product development efforts are successful, it is uncertain when, if ever, the Company will realize significant revenue from product sales. On January 21, 2020, the Company effected a 1-for-3.01581 reverse stock split of the Company’s common stock. All shares, stock options, warrants and per share information presented in the consolidated financial statements have been adjusted to reflect the reverse stock split on a retroactive basis for all periods presented. There was no change in the par value of the Company’s common stock. On February 3, 2020, the Company completed an initial public offering (the “IPO”) of 12,174,263 shares of its common stock, including the exercise in full by the underwriters of their option to purchase up to 1,587,947 additional shares of common stock, for aggregate gross proceeds of $231,311 and its shares started trading on The Nasdaq Global Select Market under the ticker symbol “BDTX.” The Company received $212,429 in net proceeds after deducting underwriting discounts and commissions and other estimated offering expenses payable by the Company. Upon closing of the IPO, all of the Company's outstanding shares of convertible preferred stock automatically converted into 21,499,770 shares of common stock. The accompanying consolidated financial statements have been prepared on the basis of continuity of operations, realization of assets, and the satisfaction of liabilities and commitments in the ordinary course of business. From its inception through December 31, 2019, the Company has funded its operations primarily with proceeds from the sale of convertible preferred and common stock and borrowings under convertible promissory notes. The Company has incurred recurring losses since its inception, including net losses of $35,258 and $8,931 for the years ended December 31, 2019 and 2018, respectively. In addition, as of December 31, 2019 and 2018, the Company had an accumulated deficit of $50,970 and $15,712, respectively. The Company expects to continue to generate operating losses for the foreseeable future. As of March 24, 2020, the issuance date of the consolidated financial statements, the Company expects that its cash and cash equivalents will be sufficient to fund its operating expenses and capital requirements into 2023.

SUMMARY OF SIGNIFICANT ACCOUNTI

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	12 Months Ended
	Dec. 31, 2019
Accounting Policies [Abstract]
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Principles of consolidation The accompanying consolidated financial statements have been prepared in accordance with GAAP and include the accounts of the Company and its wholly owned subsidiaries, Black Diamond Therapeutics (Canada), Inc. and Black Diamond Therapeutics Security Corporation, after elimination of all significant intercompany accounts and transactions. Use of estimates The preparation of the Company’s consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and the reported amounts of expenses during the reporting periods. Significant estimates and assumptions reflected in these consolidated financial statements include, but are not limited to, the accrual of research and development expenses, the valuation of common stock, the valuation of stock-based awards and the valuation of derivative liabilities. The Company bases its estimates on historical experience, known trends and other market-specific or other relevant factors that it believes to be reasonable under the circumstances. Estimates are periodically reviewed in light of changes in circumstances, facts and experience. Changes in estimates are recorded in the period in which they become known. Actual results may differ from those estimates or assumptions. Subsequent events The Company considers events or transactions that occur after the balance sheet date but before the final financial statements are issued to provide additional evidence relative to certain estimates or to identify matters that require additional disclosure. Foreign currency and currency translation The functional currency for the Company’s wholly owned foreign subsidiary, Black Diamond Therapeutics (Canada), Inc. is the United States dollar. Adjustments that arise from exchange rate changes on transactions denominated in a currency other than the local currency are included in other income (expense), net in the consolidated statements of operations, as incurred. Cash and cash equivalents The Company classifies deposits in banks, money market funds and cash invested temporarily in various instruments with maturities of three months or less at the time of purchase as cash and cash equivalents. At December 31, 2019, cash and cash equivalents includes cash on deposit at commercial banks and a money market fund that invests in U.S. Government securities. At December 31, 2018, cash consisted of cash on deposit at commercial banks. Restricted cash In connection with its operating lease commitments, the Company maintains certain balances for security deposits that are classified as restricted cash on the consolidated balance sheets. As of December 31, 2019, the Company had $55 of restricted cash, which has been classified as a non-current asset on the consolidated balance sheet. At December 31, 2018 the Company had no restricted cash. Concentrations of credit risk Financial instruments that potentially expose the Company to concentrations of credit risk consist primarily of cash. The Company generally maintains balances in various operating accounts at financial institutions in amounts that may exceed federally insured limits. The Company has not experienced any losses related to its cash and does not believe that it is subject to unusual credit risk beyond the normal credit risk associated with commercial banking relationships. Equipment Equipment is recorded at cost less accumulated depreciation. Depreciation expense is recognized using the straight-line method over the estimated useful life of each asset as follows: Estimated useful life Laboratory equipment 5 years Furniture and fixtures 5 years Computer and office equipment 3 years When assets are retired or otherwise disposed of, the cost of assets disposed of and the related accumulated depreciation is removed from the accounts and any resulting gain or loss is included in the consolidated statements of operations in the period of disposal. Expenditures for repairs and maintenance are charged to expense as incurred. Impairment of long - lived assets Long-lived assets consist of equipment. Long-lived assets to be held and used are tested for recoverability whenever events or changes in business circumstances indicate that the carrying amount of the assets may not be fully recoverable. Factors that the Company considers in deciding when to perform an impairment review include significant underperformance of the business in relation to expectations, significant negative industry or economic trends and significant changes or planned changes in the use of the assets. If an impairment review is performed to evaluate a long-lived asset group for recoverability, the Company compares forecasts of undiscounted cash flows expected to result from the use and eventual disposition of the long-lived asset group to its carrying value. An impairment loss would be recognized in loss from operations when estimated undiscounted future cash flows expected to result from the use of an asset group are less than its carrying amount. The impairment loss would be based on the excess of the carrying value of the impaired asset group over its fair value, determined based on discounted cash flows. The Company did not record any impairment losses on long-lived assets during the periods presented. Deferred offering costs The Company capitalizes certain legal, professional accounting and other third-party fees that are directly associated with in-process preferred stock or common stock financings as deferred offering costs until such financings are consummated. After consummation of the equity financing, these costs are recorded as a reduction to the carrying value of convertible preferred stock or in stockholders’ equity (deficit) as a reduction of additional paid-in capital generated as a result of the offering. Should a planned equity financing be abandoned, the deferred offering costs will be expensed immediately as a charge to operating expenses in the consolidated statements of operations. The Company had no deferred offering costs as of December 31, 2018. As of December 31, 2019, the Company recorded deferred offering costs of $2,303. Fair value measurements Certain assets and liabilities are carried at fair value under GAAP. Fair value is defined as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. Valuation techniques used to measure fair value must maximize the use of observable inputs and minimize the use of unobservable inputs. Financial assets and liabilities carried at fair value are to be classified and disclosed in one of the following three levels of the fair value hierarchy, of which the first two are considered observable and the last is considered unobservable: • Level 1 — Unadjusted quoted prices in active markets that are accessible to the reporting entity at the measurement date for identical assets and liabilities. • Level 2 — Inputs other than quoted prices in active markets for identical assets and liabilities that are observable either directly or indirectly for substantially the full term of the asset or liability. Level 2 inputs include the following: • quoted prices for similar assets and liabilities in active markets • quoted prices for identical or similar assets or liabilities in markets that are not active • observable inputs other than quoted prices that are used in the valuation of the asset or liabilities (e.g., interest rate and yield curve quotes at commonly quoted intervals) • inputs that are derived principally from or corroborated by observable market data by correlation or other means • Level 3 — Unobservable inputs for the assets or liability (i.e., supported by little or no market activity). Level 3 inputs include management’s own assumptions about the assumptions that market participants would use in pricing the asset or liability (including assumptions about risk). The carrying values of the Company’s prepaid expenses and other current assets, and accounts payable and accrued expenses approximate their fair values due to the short-term nature of these assets and liabilities. Derivative liabilities In connection with certain preferred stock financings, the Company has identified certain embedded and freestanding derivatives, which are recorded as liabilities on the consolidated balance sheets and are remeasured to fair value at each reporting date until the derivative is settled. Changes in the fair value of the derivative liabilities are recognized in the consolidated statements of operations. Classification of convertible preferred stock The Company’s convertible preferred stock is classified outside of stockholders’ deficit because the holders of such shares have liquidation rights in the event of a deemed liquidation that, in certain situations, are not solely within the control of the Company. Segment information The Company manages its operations as a single operating segment for the purposes of assessing performance and making operating decisions. The Company’s singular focus is the development of selective medicines for patients with genetically defined cancers driven by oncogenes activated by allosteric mutations. Research and development costs Research and development costs are expensed as incurred. Research and development expenses consist of costs incurred to discover, research and develop drug candidates, including personnel expenses, stock-based compensation expense, allocated facility-related and depreciation expenses, third-party license fees and external costs of outside vendors engaged to conduct preclinical development activities. Non-refundable prepayments for goods or services that will be used or rendered for future research and development activities are recorded as prepaid expenses. Such amounts are recognized as an expense as the goods are delivered or the related services are performed, or until it is no longer expected that the goods will be delivered, or the services rendered. Research contract costs and accruals The Company has entered into various research and development-related contracts with companies both inside and outside of the United States. The related costs are recorded as research and development expenses as incurred. The Company records accruals for estimated ongoing research costs. When evaluating the adequacy of the accrued liabilities, the Company analyzes progress of the studies, including the phase or completion of events, invoices received and contracted costs. Significant judgments and estimates are made in determining the accrued balances at the end of any reporting period. Actual results could differ materially from the Company’s estimates. The Company’s historical accrual estimates have not been materially different from the actual costs. Patent costs All patent-related costs incurred in connection with filing and prosecuting patent applications to operations are expensed as incurred due to the uncertainty about the recovery of the expenditure. Amounts incurred are classified as general and administrative expenses. Stock-based compensation The Company measures all stock-based awards granted to employees and directors based on the fair value on the date of grant and recognizes compensation expense of those awards over the requisite service period, which is generally the vesting period of the respective award. Forfeitures are accounted for as they occur. Generally, the Company issues awards with only service-based vesting conditions and records the expense for these awards using the straight-line method. The Company accounts for stock-based awards granted to employees and non-employees at fair value, which is measured using the Black-Scholes option-pricing model. The measurement date for employee awards is generally the date of grant. Prior to the adoption of Accounting Standards Update (“ASU”) No. 2018-07, Compensation — Stock Compensation (Topic 718) ("ASU 2018-07"), which simplifies the accounting for non-employee share based payment transactions and is discussed below under "Recently Adopted Accounting Pronouncements," the fair value measurement date for non-employee awards was the date the performance of services was completed. Stock-based compensation costs are recognized as expenses over the requisite service period, which is generally the vesting period, on a straight-line basis for all time-vested awards. Upon adoption of ASU 2018-07 on October 1, 2019, the measurement date for non-employee awards is the date of grant. The compensation expense for non-employees is recognized, without changes in the fair value of the award, over the requisite service period, which is the vesting period of the respective award. The impact on the Company’s consolidated financial statements was immaterial. The Company classifies stock-based compensation expense in its consolidated statements of operations in the same manner in which the award recipient’s payroll costs are classified or in which the award recipient’s service payments are classified. The fair value of each restricted common stock award is estimated on the date of grant based on the fair value of the Company’s common stock on that same date. The fair value of each option grant is estimated on the date of grant using the single option award approach, which requires inputs based on certain subjective assumptions, including the expected stock price volatility, the expected term of the award, the risk-free interest rate, and expected dividends (see Note 8). The Company historically has been a private company and lacks company-specific historical and implied volatility information for its stock. Therefore, it estimates its expected stock price volatility based on the historical volatility of publicly traded peer companies and expects to continue to do so until such time as it has adequate historical data regarding the volatility of its own traded stock price. The expected term of the Company’s options has been determined utilizing the “simplified” method for awards that qualify as “plain-vanilla” options. The expected term of options granted to non-employees is equal to the contractual term of the option award. The risk-free interest rate is determined by reference to the U.S. Treasury yield curve in effect at the time of grant of the award for time periods approximately equal to the expected term of the award. Expected dividend yield is based on the fact that the Company has never paid cash dividends on common stock and does not expect to pay any cash dividends in the foreseeable future. Income taxes The Company accounts for income taxes using 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 recognized in the consolidated financial statements or in the Company’s tax returns. Deferred tax assets and liabilities are determined on the basis of the differences between the financial statements and tax basis of assets and liabilities using enacted tax rates in effect for the year in which the differences are expected to reverse. Changes in deferred tax assets and liabilities are recorded in the provision for income taxes. The Company assesses the likelihood that its deferred tax assets will be recovered from future taxable income and, to the extent it believes, based upon the weight of available evidence, that it is more likely than not that all or a portion of the deferred tax assets will not be realized, a valuation allowance is established through a charge to income tax expense. Potential for recovery of deferred tax assets is evaluated by estimating the future taxable profits expected and considering prudent and feasible tax planning strategies. The Company accounts for uncertainty in income taxes recognized in the consolidated financial statements by applying a two-step process to determine the amount of tax benefit to be recognized. First, the tax position must be evaluated to determine the likelihood that it will be sustained upon external examination by the taxing authorities. If the tax position is deemed more-likely-than-not to be sustained, the tax position is then assessed to determine the amount of benefit to recognize in the consolidated financial statements. The amount of the benefit that may be recognized is the largest amount that has a greater than 50% likelihood of being realized upon ultimate settlement. The provision for income taxes includes the effects of any resulting tax reserves, or unrecognized tax benefits, that are considered appropriate as well as the related net interest and penalties. To date, the Company has not taken any uncertain tax positions or recorded any reserves, interest or penalties. Comprehensive loss Comprehensive loss includes net loss as well as other changes in stockholders’ equity (deficit) that result from transactions and economic events other than those with stockholders. For the years ended December 31, 2019 and 2018, there was no difference between net loss and comprehensive loss in the accompanying consolidated financial statements. Net income (loss) per share The Company follows the two-class method when computing net income (loss) per share as the Company has issued shares that meet the definition of participating securities. The two-class method determines net income (loss) per share for each class of common and participating securities according to dividends declared or accumulated, and participation rights in undistributed earnings. The two-class method requires income available to common stockholders for the period to be allocated between common and participating securities based upon their respective rights to receive dividends as if all income for the period had been distributed. Basic net income (loss) per share attributable to common stockholders is computed by dividing the net income (loss) attributable to common stockholders by the weighted average number of common shares outstanding for the period. Diluted net income (loss) attributable to common stockholders is computed by adjusting net income (loss) attributable to common stockholders to reallocate undistributed earnings based on the potential impact of dilutive securities. Diluted net income (loss) per share attributable to common stockholders is computed by dividing the diluted net income (loss) attributable to common stockholders by the weighted average number of common shares outstanding for the period, including potential dilutive common stock. For purpose of this calculation, outstanding options, unvested restricted common stock and convertible preferred stock are considered potential dilutive common stock and are excluded from the computation of net income (loss) per share as their effect is anti-dilutive. The Company’s convertible preferred stock contractually entitles the holders of such shares to participate in dividends but does not contractually require the holders of such shares to participate in losses of the Company. Accordingly, in periods in which the Company reports a net loss, such losses are not allocated to such participating securities. In periods in which the Company reports a net loss attributable to common stockholders, diluted net loss per share attributable to common stockholders is the same as basic net loss per share attributable to common stockholders, since dilutive common shares are not assumed to be outstanding if their effect is anti-dilutive. The Company reported a net loss attributable to common stockholders for the years ended December 31, 2019 and 2018. Recently adopted accounting pronouncements In July 2019, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2019-07, Codification Updates to SEC Sections (“ASU 2019-07”), which clarifies or improves the disclosure and presentation requirements of a variety of codification topics by aligning them with the SEC’s regulations, thereby eliminating redundancies and making the codification easier to apply. The Company prospectively adopted this update upon issuance, and it did not have a material impact on its financial position and results of operations. In June 2018, the FASB issued ASU No. 2018-07, Compensation — Stock Compensation (Topic 718): Improvements to Non-Employee Share-Based Payment Accounting (“ASU 2018-07”), which simplifies the accounting for non-employee share-based payment transactions by making the guidance consistent with the accounting for employee share-based compensation. The Company adopted this ASU on October 1, 2019 and applied the standard prospectively in accordance with the guidance. The impact on the Company's consolidated financial statements was immaterial. In May 2017, the FASB issued ASU No. 2017-09, Compensation—Stock Compensation (Topic 718): Scope of Modification Accounting (“ASU 2017-09”), which clarifies when to account for a change to the terms or conditions of a share-based payment award as a modification. Under the new guidance, modification accounting is required only if the fair value, the vesting conditions or the classification of the award (as equity or liability) changes as a result of the change in terms or conditions. ASU 2017-09 is effective for annual periods beginning after December 15, 2017, including interim periods within those fiscal years. Early adoption is permitted. The Company adopted ASU 2017-09 as of the required effective date of January 1, 2018. The adoption of ASU 2017-09 will have an impact on the modification of share-based awards, if any, after the date of adoption. In August 2016, the FASB issued ASU No. 2016-15, Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments (“ASU 2016-15”). This guidance addresses diversity in practice in how certain cash receipts and cash payments are presented in the statement of cash flows. The standard is effective for fiscal years beginning after December 15, 2018, and early adoption is permitted. The adoption of ASU 2016-15 is required to be applied retrospectively. The Company adopted ASU 2017-09 as of January 1, 2019, and the adoption did not have a material impact on the Company’s consolidated statement of cash flows. In March 2016, the FASB issued ASU No. 2016-09, Compensation—Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting (“ASU 2016-09”). ASU 2016-09 addresses several aspects of the accounting for share-based payment transactions, including the income tax consequences, classification of awards as either equity or liabilities, an option to recognize gross share compensation expense with actual forfeitures recognized as they occur, and classification on the statement of cash flows. Certain of these changes are required to be applied retrospectively, while other changes are required to be applied prospectively. The Company adopted ASU 2016-09 effective as of January 1, 2018 and elected prospectively to account for forfeitures as they occur rather than apply an estimated forfeiture rate to share-based compensation expense. The adoption of ASU 2016-09 did not have a material impact on the Company’s financial position, results of operations or cash flows. In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606) (“ASU 2014-09”), which supersedes existing revenue recognition guidance under GAAP. The standard’s core principle is that a company will recognize revenue when it transfers promised goods or services to customers in an amount that reflects the consideration to which the company expects to be entitled in exchange for those goods or services. The standard defines a five-step process to achieve this principle and will require companies to use more judgment and make more estimates than under the current guidance. The Company expects that these judgments and estimates will include identifying performance obligations in the customer contract, estimating the amount of variable consideration to include in the transaction price and allocating the transaction price to each separate performance obligation. ASU 2014-09 also requires additional disclosure about the nature, amount, timing and uncertainty of revenue and cash flows arising from customer contracts. In August 2015, the FASB issued ASU No. 2015-14, Revenue from Contracts with Customers (Topic 606): Deferral of the Effective Date , which delays the effective date of ASU 2014-09 such that the standard is effective for annual periods beginning after December 15, 2018. The FASB subsequently issued amendments to ASU 2014-09 that have the same effective date and transition date. The Company adopted ASU 2014-09 as of January 1, 2019 and the adoption did not have an impact on the Company’s consolidated financial statements as the Company does not currently have any revenue-generating arrangements. Recently issued accounting pronouncements In December 2019, the FASB issued ASU 2019-12, Income Taxes-Simplifying the Accounting for Income Taxes (“ASU 2019-12”). ASU 2019-12 eliminates certain exceptions related to the approach for intraperiod tax allocation, the methodology for calculating income taxes in an interim period and the recognition of deferred tax liabilities for outside basis differences. The new guidance also simplifies aspects of the accounting for franchise taxes and enacted changes in tax laws or rates and clarifies the accounting for transactions that result in a step-up in the tax basis of goodwill. The standard is effective for annual periods beginning after December 15, 2020 and interim periods within, with early adoption permitted. Adoption of the standard requires certain changes to be made prospectively, with some changes to be made retrospectively. The Company is currently assessing the impact of this standard on our financial condition and results of operations. In August 2018, the FASB issued ASU No. 2018-13, Fair Value Measurement (Topic 820): Disclosure Framework – Changes to the Disclosure Requirements for Fair Value Measurement (“ASU 2018-13”). The new standard removes certain disclosures, modifies certain disclosures and adds additional disclosures related to fair value measurement. The new standard will be effective beginning January 1, 2020. The adoption of ASU 2018-13 is not expected to have a material impact on the Company's financial position or results of operations upon adoption. In July 2017, the FASB issued ASU No. 2017-11, Earnings Per Share (Topic 260), Distinguishing Liabilities from Equity (Topic 480), Derivatives and Hedging (Topic 815) I (“ASU 2017-11”). Accounting for Certain Financial Instruments with Down Round Features II. Replacement of the Indefinite Deferral for Mandatorily Redeemable Financial Instruments of Certain Nonpublic Entities and Certain Mandatorily Redeemable Noncontrolling Interests with a Scope Exception (“ASU 2017-11”). Part I applies to entities that issue financial instruments such as warrants, convertible debt or convertible preferred stock that contain down-round features. Part II replaces the indefinite deferral for certain mandatorily redeemable noncontrolling interests and mandatorily redeemable financial instruments of nonpublic entities contained within ASC Topic 480 with a scope exception and does not impact the accounting for these mandatorily redeemable instruments. ASU 2017-11 is required to be adopted for annual periods beginning after December 15, 2019. This standard is effective for the Company on January 1, 2020. The Company is currently assessing the impact of this standard on our financial condition and results of operations. In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842) (“ASU 2016-02”), which requires an entity to recognize assets and liabilities arising from a lease for both financing and operating leases on their balance sheet date. ASU 2016-02 is effective for fiscal years beginning after December 15, 2018. In July 2018, an amendment was made that allows companies the option of using the effective date of the new standard as the initial application date (at the beginning of the period in which the new standard is adopted, rather than at the beginning of the earliest comparative period). This update includes a short-term lease exception for leases with a term of 12 months or less, in which a lessee can make an accounting policy election not to recognize the associated lease assets and lease liabilities on its balance sheet. Additionally, in March 2019, the FASB issued ASU 2019-01 (“ASU No. 2019-01”). ASU No. 2019-01 clarifies the transition guidance related to interim disclosures provided in the year of adoption. Lessees will continue to differentiate between finance leases (previously referred to as capital leases) and operating leases, using classification criteria that are substantially similar to the previous guidance. For lessees, the recognition, measurement, and presentation of expenses and cash flows arising from a lease did not significantly change from previous U.S. GAAP. The modified retrospective method includes several optional practical expedients that entities may elect to apply, as well as transition guidance specific to nonstandard leasing transactions. The Company has completed its assessment of the impact ASU 2016-02 will have on its financial position, results of operations, and related footnotes. The Company elected to utilize the available package of practical expedients permitted under the transition guidance within the new standard, which does not require the reassessment of the following: i) whether existing or expired arrangements are or contain a lease, ii) the lease classification of existing or expired leases, and iii) whether previous initial direct costs would qualify for capitalization under the new lease standard. Additionally, the Company made an accounting policy election to keep leases with an initial term of 12 months or less off of its balance sheet. The Company’s assessment included identifying the Company’s lease population, assessing significant leases under the new guidance and identifying changes to processes and controls. The adoption of the new standard will result in the recognition of right-of-use assets and lease liabilities of approximately $476 and $480, respectively, on the Company’s consolidated balance sheet. The adoption of the new standard will not have a material impact on the Company’s consolidated statement of operations or its liquidity.

FAIR VALUE MEASUREMENTS

FAIR VALUE MEASUREMENTS	12 Months Ended
	Dec. 31, 2019
Fair Value Disclosures [Abstract]
FAIR VALUE MEASUREMENTS	FAIR VALUE MEASUREMENTS The following tables present information about the Company’s financial assets and liabilities measured at fair value on a recurring basis and indicate the level of the fair value hierarchy used to determine such fair values: Fair value measurements at December 31, 2019 using: Level 1 Level 2 Level 3 Total Assets: Money market funds $ 24,157 $ — $ — $ 24,157 Total $ 24,157 $ — $ — $ 24,157 Liabilities: Derivative liabilities $ — $ — $ 16 $ 16 Total $ — $ — $ 16 $ 16 Fair value measurements at December 31, 2018 using: Level 1 Level 2 Level 3 Total Liabilities: Derivative liabilities $ — $ — $ 4,023 $ 4,023 Total $ — $ — $ 4,023 $ 4,023 The Company did not hold any cash equivalents as of December 31, 2018. Money market funds were valued by the Company based on quoted market prices, which represent a Level 1 measurement within the fair value hierarchy. During the years ended December 31, 2018 and 2019, there were no transfers between Level 1, Level 2 and Level 3. Valuation of derivative liabilities The fair value of the derivative liabilities related to the the series B tranche right and warrants to purchase series A convertible preferred stock (see Note 6) is based on significant inputs not observable in the market, which represents a Level 3 measurement within the fair value hierarchy. Tranche rights The Company’s issuance of series A and series B convertible preferred stock (see Note 6) provided investors the right to participate in subsequent offerings of series A and series B convertible preferred stock, respectively, in the event specified developmental and regulatory milestones were achieved. The Company classifies the tranche rights as derivative liabilities on its consolidated balance sheet as it was determined that the tranche rights met the definition of a freestanding financial instrument since they are legally detachable. It was also determined that such instruments represent forward sale contracts on redeemable shares and, accordingly, the instruments should be accounted for as a liability separate from the convertible preferred stock. The Company remeasured the derivative liabilities associated with tranche rights to fair value at each reporting date, and recognized changes in the fair value of the derivative liabilities in the consolidated statements of operations. The fair value of the derivative liabilities was determined using a back solve approach based on the price paid for the underlying series A and B convertible preferred stock and the derivative liability. The derivative liabilities were valued as forward contracts which considered inputs including, but not limited to, the probability of attaining milestones, market-based assumptions for expected term and the risk free rate. Series B tranche right The fair value of the tranche right related to the Company’s series B convertible preferred stock (see Note 6) upon issuance in December 2018 was $4,000. The change in fair value between the issuance date of December 21, 2018 and December 31, 2018 was not material. In August 2019, the Company executed a waiver of the developmental milestone whereby the tranche right was executed and an additional 11,294,902 series B preferred shares were issued, resulting in the extinguishment of the related derivative liability. The change in the fair value of the tranche right between December 2018 and the date of extinguishment was $6,393. Warrants to purchase series A convertible preferred stock In March 2017, the Company issued warrants to purchase 32,442 shares of series A convertible preferred stock. The Company accounts for the warrants to purchase series A convertible preferred stock as a liability as these warrants are freestanding financial instruments that may require the Company to transfer assets upon exercise. Such liability is not material to the consolidated financial statements, and is included in derivative liabilities. The following table presents the key inputs of the tranche rights derivative liabilities, which were extinguished in August 2019: December 31, 2019 2018 Risk-free interest rate 0.0 % 2.6 % Expected term (in years) 0.0 2.0 Expected volatility 0.0 % 65.0 % Expected dividend yield 0.0 % 0.0 % Derivative liabilities Balance - December 31, 2017 $ 8 Issuance of series B preferred stock tranche right 4,000 Change in fair value 15 Balance - December 31, 2018 4,023 Change in fair value 6,393 Exercise of series B preferred stock tranche right (10,400) Balance - December 31, 2019 $ 16

PROPERTY AND EQUIPMENT

PROPERTY AND EQUIPMENT	12 Months Ended
	Dec. 31, 2019
Property, Plant and Equipment [Abstract]
PROPERTY AND EQUIPMENT	PROPERTY AND EQUIPMENT Equipment, net consisted of the following (in thousands): December 31, 2019 2018 Laboratory equipment $ 218 $ 220 Furniture and fixtures — — Computer and office equipment 58 14 Equipment 276 234 Less: accumulated depreciation (112) (100) Total Equipment, net $ 164 $ 134 Depreciation expense for the years ended December 31, 2019 and 2018 was $47 and $44, respectively.

ACCRUED EXPENSES

ACCRUED EXPENSES	12 Months Ended
	Dec. 31, 2019
Payables and Accruals [Abstract]
ACCRUED EXPENSES	ACCRUED EXPENSES Accrued expenses consisted of the following (in thousands): ​ December 31, 2019 2018 Contracted research services $ 434 $ — Payroll and related expenses 1,182 357 Professional and consulting fees 984 95 Legal fees 299 — Total accrued expenses $ 2,899 $ 452

CONVERTIBLE PREFERRED STOCK

CONVERTIBLE PREFERRED STOCK	12 Months Ended
	Dec. 31, 2019
Temporary Equity Disclosure [Abstract]
CONVERTIBLE PREFERRED STOCK	CONVERTIBLE PREFERRED STOCK As of December 31, 2019, the Company’s Certificate of Incorporation, as amended and restated (the “Amended Certificate of Incorporation”), designated 64,871,795 authorized shares to be issued as convertible preferred stock with a par value of $0.0001 per share, of which 22,533,945 shares have been further designated as series A convertible preferred stock (the “series A preferred stock”), 22,917,726 shares have been further designated as series B convertible preferred stock (the “series B preferred stock”) and 19,420,124 shares have been further designated as series C convertible preferred stock (the “series C preferred stock”). The holders of preferred stock have liquidation rights in the event of a deemed liquidation that, in certain situations, are not solely within the control of the Company. Therefore, the series A, series B, and series C preferred stock (collectively, the “preferred stock”) are classified outside of stockholders’ deficit. Series A preferred stock financing In March 2017, the Company issued and sold 5,000,000 shares of series A preferred stock at a price of $1.00 per share for proceeds of $4,924, net of issuance costs of $76. The sale of series A preferred shares met the definition of a qualified equity financing, which triggered the automatic conversion of the Company’s outstanding notes payable plus unpaid interest into 2,501,503 series A preferred shares. The series A preferred stock financing included a provision for the issuance of an additional 5,000,000 series A preferred shares at a price of $1.00 in exchange for gross proceeds of $5,000 in the event the Company achieved certain developmental milestones. The Company classified this tranche right as a derivative liability on its consolidated balance sheet on the date of issuance, and the fair value of the tranche right on the date of issuance of $500 was recorded as both a derivative liability and as a reduction to the carrying value of the series A preferred stock. In December 2017, the Company executed a waiver of the developmental milestones whereby the tranche right was executed and an additional 5,000,000 series A preferred shares were issued. In August 2018, the Company issued and sold an additional 5,000,000 series A preferred shares at a price of $1.00 per share for proceeds of $4,899, net of issuance costs of $101. The issuance of series A preferred shares included a provision for the issuance of an additional 5,000,000 series A preferred shares at a price of $1.00 in exchange for gross proceeds of $5,000, provided the purchase occurred before December 15, 2018. In November 2018, the additional series A preferred shares were issued. Series B preferred stock financing In December 2018, the Company issued 11,166,572 series B preferred shares at a price of $3.81 for proceeds of $42,414, net of issuance costs of $86. The series B preferred stock financing included a provision for the issuance of an additional 11,166,572 series B preferred shares at a price of $3.81 in exchange for gross proceeds of $42,500 in the event the Company achieved a regulatory milestone. The Company classified this tranche right as a derivative liability on its consolidated balance sheet on the date of issuance, and the fair value of the tranche right on the date of issuance of $4,000 was recorded as both a derivative liability and as a reduction to the carrying value of the series B preferred shares. In July 2019, the Company issued and sold an additional 456,252 shares of its series B preferred stock at a price of $3.81 per share for gross proceeds of $1,736 and increased the series B tranche right provision for the issuance of an additional 128,330 series B preferred shares at a price of $3.81. In August 2019, the Company waived the clinical milestone requirement and exercised the tranche right for the second tranche of its series B preferred stock and issued an additional 11,294,902 shares of its series B preferred stock. Series C preferred stock financing In November 2019, the Company issued 19,420,124 series C preferred shares at a price of $4.38 for proceeds of $84,737, net of issuance costs of $263. As of each balance sheet date, the preferred stock consisted of the following: December 31, 2019 Shares authorized Shares issued and outstanding Carrying value Liquidation preference Common stock issuable upon conversion Series A preferred stock 22,533,945 22,501,503 $ 22,357 $ 22,502 7,461,168 Series B preferred stock 22,917,726 22,917,726 93,479 87,225 7,599,178 Series C preferred stock 19,420,124 19,420,124 84,737 85,000 6,439,424 64,871,795 64,839,353 $ 200,573 $ 194,727 21,499,770 December 31, 2018 Shares Shares Carrying Liquidation Common stock issuable upon conversion Series A convertible preferred stock 22,533,945 22,501,503 $ 22,357 $ 22,502 7,461,168 Series B convertible preferred stock 22,333,144 11,166,572 38,413 42,500 3,702,677 44,867,089 33,668,075 $ 60,770 $ 65,002 11,163,845 The holders of the preferred stock have the following rights and preferences: Voting The holders of preferred stock are entitled to vote, together with the holders of common stock, on all matters submitted to stockholders for a vote. Each holder of outstanding shares of preferred stock shall be entitled to cast the number of votes equal to the number of whole shares of common stock into which the shares of preferred stock held by such holder are convertible as of the record date for determining stockholders entitled to vote on such matter. Except as provided by law or by the other provisions of the Amended Certificate of Incorporation, holders of preferred stock vote together with the holders of common stock as a single class. The holders of record of the shares of series B preferred stock, exclusively and as a separate class, are entitled to elect two directors of the Company (the “series B directors”); the holders of record of the shares of series A preferred stock, exclusively and as a separate class, are entitled to elect two directors of the Company (the “series A directors” and together with the series B directors, the “preferred directors”). Conversion Each share of preferred stock shall be convertible, at the option of the holder, at any time and from time to time, and without the payment of additional consideration by the holder thereof, into such number of fully paid and non-assessable shares of common stock as is determined by dividing the original issue price by the conversion price (as defined below) in effect at the time of conversion. The series A original issue price and series A conversion price were equal to $1.00 ($3.02 post stock split) as of December 31, 2018 and 2019. The series B original issue price and series B conversion price were equal to $3.81 ($11.48 post stock split) as of December 31, 2018 and 2019. The series C original issue price and series C conversion price were equal to $4.38 ($13.20 post stock split) as of December 31, 2019. Such series A, series B and series C original issue prices and series A, series B and series C conversion prices, the rate at which each series of preferred stock may be converted into common stock, are subject to adjustment from time to time to reflect future stock dividends, splits, combinations, recapitalizations and similar events. The series A, series B and series C conversion prices are also subject to adjustments based on weighted-average anti-dilution provisions set forth in the Amended Certificate of Incorporation in the event that additional securities are issued at a purchase price less than the series A conversion price and/or the series B conversion and/or series C conversion price then in effect. As of December 31, 2018 and 2019, each share of series A preferred stock was convertible into one share of common stock. As of December 31, 2018 and 2019, each share of series B preferred stock was convertible into one share of common stock. As of December 31, 2019, each share of series C preferred stock was convertible into one share of common stock. Upon either (a) the closing of the sale of shares of common stock to the public at a price per share of at least $4.50, subject to appropriate adjustment in the event of any stock dividend, stock split, combination or other similar recapitalization with respect to the common stock in a firm-commitment underwritten public offering pursuant to an effective registration statement under the Securities Act of 1933, as amended, resulting in at least $75,000 of gross proceeds to the Company, a qualified IPO, or (b) the date and time, or the occurrence of an event, specified by vote or written consent of the requisite preferred holders, then (i) all outstanding shares of preferred stock shall automatically be converted into shares of common stock, at the then effective conversion rate and (ii) such stock may not be reissued by the Company. Dividends The holders of the preferred stock are entitled to receive noncumulative dividends when and if declared by Company’s board of directors. The Company may not declare, pay or set aside any dividends on any other class or series of stock of the Company, other than dividends on common stock payable in common stock, unless the holders of the preferred stock first receive, or simultaneously receive, a dividend on each outstanding preferred stock equal to (a) in the case of a dividend on any class of common stock or any class or series that is convertible into common stock, that dividend per preferred stock as would equal the product of (i) the dividend payable on each share of such class or series determined, if applicable, as if all shares of such class or series had been converted into common stock and (ii) the number of common stock issuable upon conversion of a stock the applicable series of preferred stock, or (b) in the case of a dividend on any class or series that is not convertible into common stock, at a rate per preferred stock determined by (i) dividing the amount of the dividend payable on each share of such class or series of stock by the original issue price of such class or series (subject to appropriate adjustment in the event of any bonus stock, stock dividend, stock split, combination of or other similar recapitalization with respect to such class or series) and (ii) multiplying such fraction by an amount equal to the applicable series A, series B or series C original issue price. No cash dividends were declared or paid during the years ended December 31, 2018 or 2019. Liquidation preference In the event of any liquidation, dissolution or winding up of the Company, the holders of shares of series C preferred stock, series B preferred stock and series A preferred stock then outstanding, on a pro rata, as converted and pari passu basis, shall be entitled to be paid out of the assets of the Company available for distribution to its stockholders, an amount per share equal to the applicable original issue price for such class or series of preferred stock, plus any dividends declared but unpaid thereon. If upon any such liquidation, dissolution or winding up of the Company or deemed liquidation event, the assets of the Company available for distribution to its stockholders shall be insufficient to pay the holders of shares of preferred stock the full amount to which they shall be entitled, the holders of shares of series C, series B and series A preferred stock shall stock ratably, on a pari passu basis, in any distribution of the assets available for distribution in proportion to the respective amounts which would otherwise be payable in respect of the stock held by them upon such distribution if all amounts payable on or with respect to such stock were paid in full. Unless a majority of the holders of the then outstanding preferred stock, on an as-if-converted to common stock basis, elect otherwise, a deemed liquidation event shall include a merger or consolidation (other than one in which stockholders of the Company own a majority by voting power of the outstanding shares of the surviving or acquiring company or corporation) or a sale, lease, transfer, exclusive license or other disposition of all or substantially all of the assets of the Company. Redemption The Amended Certificate of Incorporation do not provide redemption rights to the holders of preferred stock. The holders of shares of convertible preferred stock have liquidation rights in the event of a deemed liquidation that, in certain situations, are not solely within the control of the Company. Therefore, the preferred stock is classified outside of stockholders’ deficit.

COMMON STOCK

COMMON STOCK	12 Months Ended
	Dec. 31, 2019
Equity [Abstract]
COMMON STOCK	COMMON STOCK As of December 31, 2018, the Amended Certificate of Incorporation authorized the Company to issue 57,803,522 shares of common stock with a par value of $0.0001. As of December 31, 2019, the Amended Certificate of Incorporation authorized the Company to issue 80,000,000 shares of common stock with a par value of $0.0001. The voting, dividend and liquidation rights of the holders of the Company’s common stock are subject to and qualified by the rights, powers and preferences of the holders of the preferred stock as set forth above. The Company had reserved 24,027,604 shares and 12,785,541 shares as of December 31, 2019 and 2018, respectively, of common stock for the conversion of outstanding shares of preferred stock (see Note 6), the exercise of outstanding stock options, the number of shares remaining available for grant under the Company’s 2017 Equity Incentive Plan (see Note 8) and the exercise of the outstanding warrants to purchase shares of series A preferred stock, assuming all warrants to purchase shares of series A preferred stock became warrants to purchase shares of common stock at the applicable conversion ratio. On January 3, 2020, in connection with the IPO, the Company filed a restated Certificate of Incorporation, which, among other things, restated the number of shares of all classes of stock that the Company has authority to issue to 510,000,000 shares, of which (i) 500,000,000 shares shall be a class designated as common stock, par value $0.0001 per share, and (ii) 10,000,000 shares shall be a class designated as undesignated preferred stock, par value $0.0001 per share. Voting Each share of common stock entitles the holder to one vote on all matters submitted to a vote of the Company’s stockholders. Dividends Common stockholders are entitled to receive dividends, as may be declared by the board of directors. These dividends are subject to the preferential dividend rights of the holders of the Company’s preferred stock. When dividends are declared on shares of common stock, the Company must declare at the same time a dividend payable to the holders of preferred stock equivalent to the dividend amount they would receive if each preferred share were converted into common stock. The Company may not pay dividends to common stockholders until all dividends declared but unpaid on the preferred stock have been paid in full. No cash dividends were declared or paid during the years ended December 31, 2019 or 2018.

STOCK-BASED COMPENSATION

STOCK-BASED COMPENSATION	12 Months Ended
	Dec. 31, 2019
Share-based Payment Arrangement [Abstract]
STOCK-BASED COMPENSATION	STOCK-BASED COMPENSATION 2017 Equity Incentive Plan The Company’s 2017 Employee, Director and Consultant Equity Incentive Plan, as amended (the “2017 Plan”), provides for the Company to grant qualified incentive options, nonqualified options, stock grants and other stock-based awards to employees and non-employees to purchase the Company’s common stock. The 2017 Plan is administered by the board of directors, or at the discretion of the board of directors, by a committee of the board of directors. The total number of shares of common stock that may be issued under the 2017 Plan was 1,795,102 as of December 31, 2018 and 8,336,573 as of December 31, 2019, of which 1,563,187 and 138,603 shares remained available for future grant as of December 31, 2018 and 2019, respectively. The exercise price for incentive options is determined at the discretion of the board of directors. All incentive options granted to any person possessing less than 10% of the total combined voting power of all classes of stock may not have an exercise price of less than 100% of the fair market value of the common stock on the grant date. All incentive options granted to any person possessing more than 10% of the total combined voting power of all classes of stock may not have an exercise price of less than 110% of the fair market value of the common stock on the grant date. The option term for incentive awards may not be greater than ten years from the date of the grant. Incentive options granted to persons possessing more than 10% of the total combined voting power of all classes of stock may not have an option term of greater than five years from the date of the grant. The vesting period for equity-based awards is determined at the discretion of the board of directors, which is generally four years. For awards granted to employees and non-employees with four Shares that are expired, terminated, surrendered or canceled under the 2017 Plan without having been fully exercised will be available for future awards. 2020 Stock Option and Incentive Plan The 2020 Stock Option and Incentive Plan (the “2020 Plan”) was approved by our board of directors on December 5, 2019, and the Company’s stockholders on January 14, 2020 and became effective on the date immediately prior to the date on which the registration statement for the Company’s IPO was declared effective. The 2020 Plan provides for the grant of incentive stock options, non-qualified stock options, stock appreciation rights, restricted stock units, restricted stock awards, unrestricted stock awards, cash-based awards and dividend equivalent rights to the Company’s officers, employees, directors and consultants. The number of shares initially reserved for issuance under the 2020 Plan is 6,665,891, which shall be cumulatively increased on January 1, 2021 and each January 1 thereafter by 4% of the number of shares of the Company’s common stock outstanding on the immediately preceding December 31 or such lesser number of shares determined by the Company’s board of directors or compensation, nomination, and corporate governance committee of the board of directors. 2020 Employee Stock Purchase Plan The 2020 Employee Stock Purchase Plan (the “2020 ESPP”) was approved by the Company’s board of directors on December 5, 2019, and our stockholders on January 14, 2020, and became effective on the date immediately prior to the date on which the registration statement for the Company’s IPO was declared effective. A total of 326,364 shares of common stock were initially reserved for issuance under this plan, which shall be cumulatively increased on January 1, 2021 and each January 1 thereafter by 1% of the number of shares of the Company’s common stock outstanding on the immediately preceding December 31 or such lesser number of shares determined by the Company’s board of directors or compensation, nomination and corporate governance committee of the board of directors. Option valuation The assumptions that the Company used to determine the grant-date fair value of options granted to employees and directors were as follows, presented on a weighted-average basis: December 31, 2019 2018 Risk-free interest rate 1.68 % 2.87 % Expected term (in years) 6.0 6.1 Expected volatility 62.2 % 58.4 % Expected dividend yield 0 % 0 % The assumptions that the Company used to determine the fair value of options granted to non-employees were as follows, presented on a weighted-average basis: December 31, 2019 2018 Risk-free interest rate 1.68 % 2.87 % Expected term (in years) 6.0 9.7 Expected volatility 62.2 % 58.4 % Expected dividend yield 0 % 0 % Options Through December 31, 2019, all options granted by the Company under the 2017 Plan were for the purchase of shares of common stock. The following table summarizes option activity under the 2017 Plan since December 31, 2018 (in thousands, except share and per share amounts): Options Weighted Average Exercise Price Weighted Average Remaining Life (in Years) Intrinsic Value (in thousands) Outstanding December 31, 2018 47,735 $ 0.66 9.5 $ 121 Granted 2,330,739 $ 8.18 Outstanding December 31, 2019 2,378,474 $ 8.03 9.7 $ 6,722 Options vested or expected to vest as of December 31, 2019 2,378,474 $ 8.03 9.7 $ 6,722 Options exercisable as of December 31, 2019 111,633 $ 4.98 9.2 $ 656 The aggregate intrinsic value of options is calculated as the difference between the exercise price of the options and the fair value of the Company’s common stock for those options that had exercise prices lower than the fair value of the Company’s common stock. The weighted-average grant-date fair value per share of options granted during the years ended December 31, 2018 and 2019 was $0.39 and $4.82, respectively. The total fair value of options vested during the years ended December 31, 2018 and 2019 was $7 and $319, respectively. Restricted stock Under terms of the restricted stock agreements covering the common stock, shares of restricted common stock are subject to a vesting schedule. The majority of restricted stock vests over a three The following table summarizes restricted stock activity since December 31, 2017: Number of shares Weighted average grant date fair value Unvested restricted common stock as of December 31, 2017 91,680 $ 0.30 Granted 92,497 $ 0.72 Vested (51,532) $ 0.30 Unvested restricted common stock as of December 31, 2018 132,645 $ 0.51 Granted 62,988 $ 5.22 Vested (195,633) $ 5.94 Unvested restricted common stock as of December 31, 2019 — $ — The aggregate fair value of restricted stock that vested during the years ended December 31, 2018 and 2019 was $40 and $420, respectively. The Company recorded stock-based compensation expense for restricted stock of $53 and $1,973, during the years ended December 31, 2018 and 2019, respectively. Stock-based compensation expense The Company recorded stock-based compensation expense in the following expense categories of its consolidated statements of operations (in thousands): December 31, 2019 2018 Research and development $ 3,171 $ 62 General and administrative 472 1 $ 3,643 $ 63 For options granted in June 2019, the board of directors determined that the fair value of the Company’s common stock was $3.20 per share as of the grant date. However, the fair value of the Company’s common stock at the date of the grant was adjusted to $4.13 per share in connection with a retrospective fair value assessment solely for accounting purposes. Accordingly, stock-based compensation recorded during the year ended December 31, 2019 was based on the adjusted fair value for the options granted in June 2019. As of December 31, 2018 and 2019, total unrecognized compensation cost related to the unvested stock-based awards was $335 and $11,315, respectively, which is expected to be recognized over a weighted average period of 3.3 and 3.5 years, respectively.

INCOME TAXES

INCOME TAXES	12 Months Ended
	Dec. 31, 2019
Income Tax Disclosure [Abstract]
INCOME TAXES	INCOME TAXES For the years ended December 31, 2019 and 2018, the Company recorded no income tax benefit for the net operating losses incurred each year, due to its uncertainty of realizing a benefit from those items. A reconciliation of income taxes computed using the U.S. federal statutory rate to that reflected in operations as of December 31, 2019 and 2018, respectively, is as follows: December 31, 2019 2018 U.S. federal statutory income tax rate 21.0 % 21.0 % State and local taxes, net of federal benefit 1.6 % 5.1 % Permanent differences (4.2) % 0.0 % Research and development credits 1.6 % 3.7 % Change in valuation allowance (19.8) % (29.8) % Other (0.2) % 0.0 % Effective income tax rate 0.0 % 0.0 % The tax effects of temporary differences that gave rise to significant portions of the deferred tax assets were as follows (in thousands): Tax year ended December 31, 2019 2018 Deferred tax assets (liabilities): Net operating loss carryforwards $ 9,512 $ 2,904 Research and development tax credits 1,014 459 Accrual to cash adjustment — 657 Accruals and other 280 — Stock-based compensation 196 — Total deferred tax assets 11,002 4,020 Valuation Allowance (10,995) (4,010) Subtotal 7 10 Net fixed assets (7) (10) Net deferred tax assets $ — $ — As of December 31, 2019, the Company had federal and state net operating loss carryforwards of $39,596 and $20,075, respectively, which may be used to offset future taxable income, if any. These amounts begin to expire in 2036. The federal net operating losses generated in 2018 and 2019 can be carried forward indefinitely. The Company also has net operating loss carryforwards in Canada of $222 that are set to expire beginning in 2038. Additionally, the Company had federal research and development tax credit carryforwards of $1,014 that expire at various dates through 2039. In assessing the realizability of the net deferred tax asset, the Company considers all relevant positive and negative evidence in determining whether it is more likely than not that some portion or all of the deferred income tax assets will not be realized. The realization of the gross deferred tax assets is dependent on several factors, including the generation of sufficient taxable income prior to the expiration of the net operating loss carryforwards. Management believes that it is more likely than not that the Company’s deferred income tax assets will not be realized. As such, there is a full valuation allowance against the net deferred tax assets as of December 31, 2019 and 2018. The valuation allowance increased by $6,985 during the year ended December 31, 2019 primarily as a result of net losses generated during the period. Utilization of the net operating loss carryforwards and research and development tax credit carryforwards may be subject to an annual limitation under Section 382 of the Internal Revenue Code of 1986, and corresponding provisions of state law, due to ownership changes that have occurred previously or that could occur in the future. These ownership changes may limit the amount of carryforwards that can be utilized annually to offset future taxable income. In general, an ownership change, as defined by Section 382, results from transactions increasing the ownership of certain shareholders or public groups in the stock of a corporation by more than 50% over a three-year period. The Company has not conducted a study to assess whether a change of control has occurred or whether there have been multiple changes of control since inception due to the significant complexity and cost associated with such a study. If the Company has experienced a change of control, as defined by Section 382, at any time since inception, utilization of the net operating loss carryforwards or research and development tax credit carryforwards would be subject to an annual limitation under Section 382, which is determined by first multiplying the value of the Company’s stock at the time of the ownership change by the applicable long-term tax-exempt rate, and then could be subject to additional adjustments, as required. Any limitation may result in expiration of a portion of the net operating loss carryforwards or research and development tax credit carryforwards before utilization. Further, until a study is completed and any limitation is known, no amounts are being presented as an uncertain tax position. The Company also has not conducted a study of its research and development credit carryforwards, which may result in an adjustment to research and development credit carryforwards. A full valuation allowance has been provided against the Company’s research and development credits and, if an adjustment is required, this adjustment would be offset by an adjustment to the valuation allowance. Thus, there would be no impact to the balance sheets or statements of operations if an adjustment were required. Further, until a study is completed and any limitation is known, no amounts are being presented as an uncertain tax position. The Company applies the accounting guidance in ASC 740 related to accounting for uncertainty in income taxes. The Company’s reserves related to taxes are based on a determination of whether, and how much of, a tax benefit taken by the Company in its tax filings or positions is more likely than not to be realized following resolution of any potential contingencies present related to the tax benefit. As of December 31, 2019 and 2018, the Company had no unrecognized tax benefits. The Company will recognize interest and penalties related to uncertain tax positions in income tax expense. As of December 31, 2019 and 2018, the Company had no accrued interest or penalties related to uncertain tax positions. The Company files tax returns as prescribed by the tax laws of the jurisdictions in which it operates. In the normal course of business, the Company is subject to examination by federal and state jurisdictions, where applicable. There are currently no pending tax examinations. As of December 31, 2019 and 2018, the Company’s tax years are still open under statute from 2016 to the present. The Company’s foreign subsidiary has incurred losses since inception and the Company had no undistributed earnings as of December 31, 2019.

NET LOSS PER SHARE

NET LOSS PER SHARE	12 Months Ended
	Dec. 31, 2019
Earnings Per Share [Abstract]
NET LOSS PER SHARE	NET LOSS PER SHARE Net loss per share The following table summarizes the computation of basic and diluted net loss per share attributable to common stockholders of the Company (in thousands, except share and per share amounts): December 31, 2019 2018 Net loss attributable to common stockholders $ (35,258) $ (8,931) Weighted average common shares outstanding, basic and diluted 2,075,753 2,018,623 Net loss per share, basic and diluted $ (16.99) $ (4.42) The Company’s unvested restricted common shares at December 31, 2018 have been excluded from the computation of basic net loss per share attributable to common stockholders. The Company had no unvested restricted common shares outstanding at December 31, 2019 (see Note 8). The Company’s potentially dilutive securities, which include options, unvested restricted stock, convertible preferred stock and warrants to purchase convertible preferred stock, have been excluded from the computation of diluted net loss per share attributable to common stockholders as the effect would be to reduce the net loss per share attributable to common stockholders. Therefore, the weighted average number of common shares outstanding used to calculate both basic and diluted net loss per share attributable to common stockholders is the same. The Company excluded the following potential common shares, presented based on amounts outstanding at each period end, from the computation of diluted net loss per share attributable to common stockholders for the periods indicated because including them would have had an anti-dilutive effect: December 31, 2019 2018 Options to purchase common stock 2,378,474 47,735 Unvested restricted stock — 132,645 Preferred stock (as converted to common stock) 21,499,770 11,163,838 Warrants to purchase shares of series A preferred stock (as converted to common stock) 10,757 10,757 23,889,001 11,354,975

COMMITMENTS AND CONTINGENCIES

COMMITMENTS AND CONTINGENCIES	12 Months Ended
	Dec. 31, 2019
Commitments and Contingencies Disclosure [Abstract]
COMMITMENTS AND CONTINGENCIES	COMMITMENTS AND CONTINGENCIES Lease agreements In February 2019, the Company entered into an agreement to lease approximately 2,357 square feet of office space for its principal office, which is located in Cambridge, MA. The lease expires on April 30, 2022, subject to an option to extend the lease for three The Company classifies the lease as an operating lease and records rent expense on a straight-line basis over the term of the lease. The Company is obligated to make minimum lease payments under the facility lease as follows (in thousands): Years Ending December 31, 2020 $ 223 2021 228 2022 77 2023 — Total $ 528 Rent expense for the years ended December 31, 2019 and 2018 was $415 and $36, respectively. We enter into contracts in the normal course of business with contract research organizations ("CROs"), contract manufacturing organizations ("CMOs") and other third parties for preclinical research studies, Clinical Trials and testing and manufacturing services. These contracts do not contain minimum purchase commitments and are cancelable upon prior written notice. Payments due upon cancellation consist only of payments for services provided or expenses incurred, including noncancelable obligations of service providers, up to the date of cancellation. Indemnification agreements In the ordinary course of business, the Company may provide indemnification of varying scope and terms to vendors, lessors, business partners and other parties with respect to certain matters including, but not limited to, losses arising out of breach of such agreements or from intellectual property infringement claims made by third parties. In addition, the Company has entered into indemnification agreements with members of its board of directors and executive officers that will require the Company, among other things, to indemnify them against certain liabilities that may arise by reason of their status or service as directors or officers. The maximum potential amount of future payments the Company could be required to make under these indemnification agreements is, in many cases, unlimited. To date, the Company has not incurred any material costs as a result of such indemnifications. The Company is not aware of any indemnification arrangements that could have a material effect on its financial position, results of operations or cash flows, and it has not accrued any liabilities related to such obligations in its consolidated financial statements as of December 31, 2019 or 2018. Legal proceedings The Company is not currently party to and is not aware of any material legal proceedings. At each reporting date, the Company evaluates whether or not a potential loss amount or a potential range of loss is probable and reasonably estimable under the provisions of the authoritative guidance that addresses accounting for contingencies. The Company expenses as incurred the costs related to such legal proceedings.

BENEFIT PLANS

BENEFIT PLANS	12 Months Ended
	Dec. 31, 2019
Retirement Benefits [Abstract]
BENEFIT PLANS	BENEFIT PLANSIn 2018 the Company established a Simplified Employee Pension (“SEP”) defined-contribution savings plan. This plan covers substantially all employees who meet minimum age and service requirements. The Company provides contributions of 6% of each participant’s salary. Employees are immediately and fully vested in the Company’s contribution. During the year ended December 31, 2019 and 2018, the Company contributed $200 and $20 to the plan, respectively.

RELATED-PARTY TRANSACTIONS

RELATED-PARTY TRANSACTIONS	12 Months Ended
	Dec. 31, 2019
Related Party Transactions [Abstract]
RELATED-PARTY TRANSACTIONS	RELATED-PARTY TRANSACTIONSThe Company is party to a services agreement, which was entered into in March 2017 and amended in November 2017, with Ridgeline, an entity owned by one of its investors, whereby an individual who is a Company director and was executive officer until September 2019 and other employees of Ridgeline provide the Company with management, scientific, business development and other operational services. The agreement is effective until either party elects to terminate. Under the services agreement the Company will pay for services based on the costs incurred plus a markup of ten percent (10%) and reimburse for certain pass-through costs. The services agreement was further amended in December 2018. Subsequent to this amendment, in connection with the services provided, the Company pays Ridgeline $950 per month, which is reconciled on a quarterly basis with the actual expenses incurred by Ridgeline on its behalf. Total prepaids with related party were $916 as of December 31, 2019. Total amounts due to related party were $1,707 as of December 31, 2018. Total service fees incurred were $10,411 and $2,728, for the years ended December 31, 2019 and 2018. On March 20, 2020, the services agreement was further amended in order to transition from the previous service model to a more limited consulting arrangement with Ridgeline in 2020. Under the amendment Ridgeline will invoice the Company for services performed on an ongoing monthly basis.

SELECTED QUARTERLY FINANCIAL DA

SELECTED QUARTERLY FINANCIAL DATA (UNAUDITED)	12 Months Ended
	Dec. 31, 2019
Quarterly Financial Information Disclosure [Abstract]
SELECTED QUARTERLY FINANCIAL DATA (UNAUDITED)	SELECTED QUARTERLY FINANCIAL DATA (UNAUDITED) The following table contains quarterly financial information for 2019 and 2018. The Company believes that the following information reflects all normal recurring adjustments necessary for a fair presentation of the information for the periods presented. The operating results for any quarter are not necessarily indicative of results for any future period. 2019 March 31, June 30, September 30, December 31, Total (in thousands, except per share data) Revenue $ — $ — $ — $ — $ — Total operating expenses 3,841 6,999 8,148 10,344 29,332 Loss from operations (3,841) (6,999) (8,148) (10,344) (29,332) Net loss attributable to common stockholders (3,828) (12,287) (9,268) (9,875) (35,258) Net loss per share attributable to common stockholders, basic and diluted $ (1.87) $ (5.99) $ (4.50) $ (4.63) $ (16.99) 2018 March 31, June 30, September 30, December 31, Total (in thousands, except per share data) Revenue $ — $ — $ — $ — $ — Total operating expenses 1,605 1,914 2,339 3,046 8,904 Loss from operations (1,605) (1,914) (2,339) (3,046) (8,904) Net loss attributable to common stockholders (1,592) (1,913) (2,360) (3,066) (8,931) Net loss per share attributable to common stockholders, basic and diluted $ (0.80) $ (0.95) $ (1.16) $ (1.51) $ (4.42)

SUMMARY OF SIGNIFICANT ACCOUN_2

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)	12 Months Ended
	Dec. 31, 2019
Accounting Policies [Abstract]
Principles of consolidation	Black Diamond Therapeutics, Inc. (the “Company”) is a precision oncology medicine company pioneering the discovery and development of small molecule, tumor-agnostic therapies. The Company was originally organized as a limited liability company in December 2014 under the name ASET Therapeutics LLC. In September 2016 the Company was converted to a corporation under the laws of the State of Delaware under the name ASET Therapeutics, Inc. The Company changed its name to Black Diamond Therapeutics, Inc. in January 2018. Since its inception, the Company has devoted substantially all of its efforts to raising capital, obtaining financing, and incurring research and development costs related to the development of its mutation, allostery, and pharmacology computational and discovery platform. The Company is subject to risks and uncertainties common to early-stage companies in the biotechnology industry. There can be no assurance that the Company’s research and development will be successfully completed, that adequate protection for the Company’s technology will be obtained, that any products developed will obtain necessary government regulatory approval or that any products, if approved, will be commercially viable. The Company operates in an environment of rapid technological innovation and substantial competition from pharmaceutical and biotechnological companies. In addition, the Company is dependent upon the services of its employees, consultants and service providers including a related party Ridgeline Therapeutics GmbH (“Ridgeline”). Even if the Company’s product development efforts are successful, it is uncertain when, if ever, the Company will realize significant revenue from product sales.
Principles of consolidation	Principles of consolidation The accompanying consolidated financial statements have been prepared in accordance with GAAP and include the accounts of the Company and its wholly owned subsidiaries, Black Diamond Therapeutics (Canada), Inc. and Black Diamond Therapeutics Security Corporation, after elimination of all significant intercompany accounts and transactions.
Use of estimates	Use of estimates The preparation of the Company’s consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and the reported amounts of expenses during the reporting periods. Significant estimates and assumptions reflected in these consolidated financial statements include, but are not limited to, the accrual of research and development expenses, the valuation of common stock, the valuation of stock-based awards and the valuation of derivative liabilities. The Company bases its estimates on historical experience, known trends and other market-specific or other relevant factors that it believes to be reasonable under the circumstances. Estimates are periodically reviewed in light of changes in circumstances, facts and experience. Changes in estimates are recorded in the period in which they become known. Actual results may differ from those estimates or assumptions.
Subsequent events	Subsequent events The Company considers events or transactions that occur after the balance sheet date but before the final financial statements are issued to provide additional evidence relative to certain estimates or to identify matters that require additional disclosure.
Foreign currency and currency translation	Foreign currency and currency translation The functional currency for the Company’s wholly owned foreign subsidiary, Black Diamond Therapeutics (Canada), Inc. is the United States dollar. Adjustments that arise from exchange rate changes on transactions denominated in a currency other than the local currency are included in other income (expense), net in the consolidated statements of operations, as incurred.
Cash and cash equivalents	Cash and cash equivalents The Company classifies deposits in banks, money market funds and cash invested temporarily in various instruments with maturities of three months or less at the time of purchase as cash and cash equivalents. At December 31, 2019, cash and cash equivalents includes cash on deposit at commercial banks and a money market fund that invests in U.S. Government securities. At December 31, 2018, cash consisted of cash on deposit at commercial banks.
Restricted cash	Restricted cash In connection with its operating lease commitments, the Company maintains certain balances for security deposits that are classified as restricted cash on the consolidated balance sheets
Concentrations of credit risk	Concentrations of credit risk Financial instruments that potentially expose the Company to concentrations of credit risk consist primarily of cash. The Company generally maintains balances in various operating accounts at financial institutions in amounts that may exceed federally insured limits. The Company has not experienced any losses related to its cash and does not believe that it is subject to unusual credit risk beyond the normal credit risk associated with commercial banking relationships.
Equipment	Equipment Equipment is recorded at cost less accumulated depreciation. Depreciation expense is recognized using the straight-line method over the estimated useful life of each asset as follows: Estimated useful life Laboratory equipment 5 years Furniture and fixtures 5 years Computer and office equipment 3 years
Impairment of long - lived assets	Impairment of long - lived assets Long-lived assets consist of equipment. Long-lived assets to be held and used are tested for recoverability whenever events or changes in business circumstances indicate that the carrying amount of the assets may not be fully recoverable. Factors that the Company considers in deciding when to perform an impairment review include significant underperformance of the business in relation to expectations, significant negative industry or economic trends and significant changes or planned changes in the use of the assets. If an impairment review is performed to evaluate a long-lived asset group for recoverability, the Company compares forecasts of undiscounted cash flows expected to result from the use and eventual disposition of the long-lived asset group to its carrying value. An impairment loss would be recognized in loss from operations when estimated undiscounted future cash flows expected to result from the use of an asset group are less than its carrying amount. The impairment loss would be based on the excess of the carrying value of the impaired asset group over its fair value, determined based on discounted cash flows. The Company did not record any impairment losses on long-lived assets during the periods presented.
Deferred offering costs	Deferred offering costsThe Company capitalizes certain legal, professional accounting and other third-party fees that are directly associated with in-process preferred stock or common stock financings as deferred offering costs until such financings are consummated. After consummation of the equity financing, these costs are recorded as a reduction to the carrying value of convertible preferred stock or in stockholders’ equity (deficit) as a reduction of additional paid-in capital generated as a result of the offering. Should a planned equity financing be abandoned, the deferred offering costs will be expensed immediately as a charge to operating expenses in the consolidated statements of operations
Fair value measurements	Fair value measurements Certain assets and liabilities are carried at fair value under GAAP. Fair value is defined as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. Valuation techniques used to measure fair value must maximize the use of observable inputs and minimize the use of unobservable inputs. Financial assets and liabilities carried at fair value are to be classified and disclosed in one of the following three levels of the fair value hierarchy, of which the first two are considered observable and the last is considered unobservable: • Level 1 — Unadjusted quoted prices in active markets that are accessible to the reporting entity at the measurement date for identical assets and liabilities. • Level 2 — Inputs other than quoted prices in active markets for identical assets and liabilities that are observable either directly or indirectly for substantially the full term of the asset or liability. Level 2 inputs include the following: • quoted prices for similar assets and liabilities in active markets • quoted prices for identical or similar assets or liabilities in markets that are not active • observable inputs other than quoted prices that are used in the valuation of the asset or liabilities (e.g., interest rate and yield curve quotes at commonly quoted intervals) • inputs that are derived principally from or corroborated by observable market data by correlation or other means • Level 3 — Unobservable inputs for the assets or liability (i.e., supported by little or no market activity). Level 3 inputs include management’s own assumptions about the assumptions that market participants would use in pricing the asset or liability (including assumptions about risk). The carrying values of the Company’s prepaid expenses and other current assets, and accounts payable and accrued expenses approximate their fair values due to the short-term nature of these assets and liabilities.
Derivatives liabilities	Derivative liabilities In connection with certain preferred stock financings, the Company has identified certain embedded and freestanding derivatives, which are recorded as liabilities on the consolidated balance sheets and are remeasured to fair value at each reporting date until the derivative is settled. Changes in the fair value of the derivative liabilities are recognized in the consolidated statements of operations.
Classification of convertible preferred stock	Classification of convertible preferred stock The Company’s convertible preferred stock is classified outside of stockholders’ deficit because the holders of such shares have liquidation rights in the event of a deemed liquidation that, in certain situations, are not solely within the control of the Company.
Segment information	Segment information The Company manages its operations as a single operating segment for the purposes of assessing performance and making operating decisions. The Company’s singular focus is the development of selective medicines for patients with genetically defined cancers driven by oncogenes activated by allosteric mutations.
Research and development costs and research contract costs and accruals	Research and development costs Research and development costs are expensed as incurred. Research and development expenses consist of costs incurred to discover, research and develop drug candidates, including personnel expenses, stock-based compensation expense, allocated facility-related and depreciation expenses, third-party license fees and external costs of outside vendors engaged to conduct preclinical development activities. Non-refundable prepayments for goods or services that will be used or rendered for future research and development activities are recorded as prepaid expenses. Such amounts are recognized as an expense as the goods are delivered or the related services are performed, or until it is no longer expected that the goods will be delivered, or the services rendered. Research contract costs and accruals
Patent costs	Patent costsAll patent-related costs incurred in connection with filing and prosecuting patent applications to operations are expensed as incurred due to the uncertainty about the recovery of the expenditure. Amounts incurred are classified as general and administrative expenses.
Stock-based compensation	Stock-based compensation The Company measures all stock-based awards granted to employees and directors based on the fair value on the date of grant and recognizes compensation expense of those awards over the requisite service period, which is generally the vesting period of the respective award. Forfeitures are accounted for as they occur. Generally, the Company issues awards with only service-based vesting conditions and records the expense for these awards using the straight-line method. The Company accounts for stock-based awards granted to employees and non-employees at fair value, which is measured using the Black-Scholes option-pricing model. The measurement date for employee awards is generally the date of grant. Prior to the adoption of Accounting Standards Update (“ASU”) No. 2018-07, Compensation — Stock Compensation (Topic 718) ("ASU 2018-07"), which simplifies the accounting for non-employee share based payment transactions and is discussed below under "Recently Adopted Accounting Pronouncements," the fair value measurement date for non-employee awards was the date the performance of services was completed. Stock-based compensation costs are recognized as expenses over the requisite service period, which is generally the vesting period, on a straight-line basis for all time-vested awards. Upon adoption of ASU 2018-07 on October 1, 2019, the measurement date for non-employee awards is the date of grant. The compensation expense for non-employees is recognized, without changes in the fair value of the award, over the requisite service period, which is the vesting period of the respective award. The impact on the Company’s consolidated financial statements was immaterial. The Company classifies stock-based compensation expense in its consolidated statements of operations in the same manner in which the award recipient’s payroll costs are classified or in which the award recipient’s service payments are classified.
Income taxes	Income taxes The Company accounts for income taxes using 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 recognized in the consolidated financial statements or in the Company’s tax returns. Deferred tax assets and liabilities are determined on the basis of the differences between the financial statements and tax basis of assets and liabilities using enacted tax rates in effect for the year in which the differences are expected to reverse. Changes in deferred tax assets and liabilities are recorded in the provision for income taxes. The Company assesses the likelihood that its deferred tax assets will be recovered from future taxable income and, to the extent it believes, based upon the weight of available evidence, that it is more likely than not that all or a portion of the deferred tax assets will not be realized, a valuation allowance is established through a charge to income tax expense. Potential for recovery of deferred tax assets is evaluated by estimating the future taxable profits expected and considering prudent and feasible tax planning strategies.
Comprehensive loss	Comprehensive lossComprehensive loss includes net loss as well as other changes in stockholders’ equity (deficit) that result from transactions and economic events other than those with stockholders.
Net income (loss) per share	Net income (loss) per share The Company follows the two-class method when computing net income (loss) per share as the Company has issued shares that meet the definition of participating securities. The two-class method determines net income (loss) per share for each class of common and participating securities according to dividends declared or accumulated, and participation rights in undistributed earnings. The two-class method requires income available to common stockholders for the period to be allocated between common and participating securities based upon their respective rights to receive dividends as if all income for the period had been distributed.
Recently adopted and issued accounting pronouncements	Recently adopted accounting pronouncements In July 2019, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2019-07, Codification Updates to SEC Sections (“ASU 2019-07”), which clarifies or improves the disclosure and presentation requirements of a variety of codification topics by aligning them with the SEC’s regulations, thereby eliminating redundancies and making the codification easier to apply. The Company prospectively adopted this update upon issuance, and it did not have a material impact on its financial position and results of operations. In June 2018, the FASB issued ASU No. 2018-07, Compensation — Stock Compensation (Topic 718): Improvements to Non-Employee Share-Based Payment Accounting (“ASU 2018-07”), which simplifies the accounting for non-employee share-based payment transactions by making the guidance consistent with the accounting for employee share-based compensation. The Company adopted this ASU on October 1, 2019 and applied the standard prospectively in accordance with the guidance. The impact on the Company's consolidated financial statements was immaterial. In May 2017, the FASB issued ASU No. 2017-09, Compensation—Stock Compensation (Topic 718): Scope of Modification Accounting (“ASU 2017-09”), which clarifies when to account for a change to the terms or conditions of a share-based payment award as a modification. Under the new guidance, modification accounting is required only if the fair value, the vesting conditions or the classification of the award (as equity or liability) changes as a result of the change in terms or conditions. ASU 2017-09 is effective for annual periods beginning after December 15, 2017, including interim periods within those fiscal years. Early adoption is permitted. The Company adopted ASU 2017-09 as of the required effective date of January 1, 2018. The adoption of ASU 2017-09 will have an impact on the modification of share-based awards, if any, after the date of adoption. In August 2016, the FASB issued ASU No. 2016-15, Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments (“ASU 2016-15”). This guidance addresses diversity in practice in how certain cash receipts and cash payments are presented in the statement of cash flows. The standard is effective for fiscal years beginning after December 15, 2018, and early adoption is permitted. The adoption of ASU 2016-15 is required to be applied retrospectively. The Company adopted ASU 2017-09 as of January 1, 2019, and the adoption did not have a material impact on the Company’s consolidated statement of cash flows. In March 2016, the FASB issued ASU No. 2016-09, Compensation—Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting (“ASU 2016-09”). ASU 2016-09 addresses several aspects of the accounting for share-based payment transactions, including the income tax consequences, classification of awards as either equity or liabilities, an option to recognize gross share compensation expense with actual forfeitures recognized as they occur, and classification on the statement of cash flows. Certain of these changes are required to be applied retrospectively, while other changes are required to be applied prospectively. The Company adopted ASU 2016-09 effective as of January 1, 2018 and elected prospectively to account for forfeitures as they occur rather than apply an estimated forfeiture rate to share-based compensation expense. The adoption of ASU 2016-09 did not have a material impact on the Company’s financial position, results of operations or cash flows. In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606) (“ASU 2014-09”), which supersedes existing revenue recognition guidance under GAAP. The standard’s core principle is that a company will recognize revenue when it transfers promised goods or services to customers in an amount that reflects the consideration to which the company expects to be entitled in exchange for those goods or services. The standard defines a five-step process to achieve this principle and will require companies to use more judgment and make more estimates than under the current guidance. The Company expects that these judgments and estimates will include identifying performance obligations in the customer contract, estimating the amount of variable consideration to include in the transaction price and allocating the transaction price to each separate performance obligation. ASU 2014-09 also requires additional disclosure about the nature, amount, timing and uncertainty of revenue and cash flows arising from customer contracts. In August 2015, the FASB issued ASU No. 2015-14, Revenue from Contracts with Customers (Topic 606): Deferral of the Effective Date , which delays the effective date of ASU 2014-09 such that the standard is effective for annual periods beginning after December 15, 2018. The FASB subsequently issued amendments to ASU 2014-09 that have the same effective date and transition date. The Company adopted ASU 2014-09 as of January 1, 2019 and the adoption did not have an impact on the Company’s consolidated financial statements as the Company does not currently have any revenue-generating arrangements. Recently issued accounting pronouncements In December 2019, the FASB issued ASU 2019-12, Income Taxes-Simplifying the Accounting for Income Taxes (“ASU 2019-12”). ASU 2019-12 eliminates certain exceptions related to the approach for intraperiod tax allocation, the methodology for calculating income taxes in an interim period and the recognition of deferred tax liabilities for outside basis differences. The new guidance also simplifies aspects of the accounting for franchise taxes and enacted changes in tax laws or rates and clarifies the accounting for transactions that result in a step-up in the tax basis of goodwill. The standard is effective for annual periods beginning after December 15, 2020 and interim periods within, with early adoption permitted. Adoption of the standard requires certain changes to be made prospectively, with some changes to be made retrospectively. The Company is currently assessing the impact of this standard on our financial condition and results of operations. In August 2018, the FASB issued ASU No. 2018-13, Fair Value Measurement (Topic 820): Disclosure Framework – Changes to the Disclosure Requirements for Fair Value Measurement (“ASU 2018-13”). The new standard removes certain disclosures, modifies certain disclosures and adds additional disclosures related to fair value measurement. The new standard will be effective beginning January 1, 2020. The adoption of ASU 2018-13 is not expected to have a material impact on the Company's financial position or results of operations upon adoption. In July 2017, the FASB issued ASU No. 2017-11, Earnings Per Share (Topic 260), Distinguishing Liabilities from Equity (Topic 480), Derivatives and Hedging (Topic 815) I (“ASU 2017-11”). Accounting for Certain Financial Instruments with Down Round Features II. Replacement of the Indefinite Deferral for Mandatorily Redeemable Financial Instruments of Certain Nonpublic Entities and Certain Mandatorily Redeemable Noncontrolling Interests with a Scope Exception (“ASU 2017-11”). Part I applies to entities that issue financial instruments such as warrants, convertible debt or convertible preferred stock that contain down-round features. Part II replaces the indefinite deferral for certain mandatorily redeemable noncontrolling interests and mandatorily redeemable financial instruments of nonpublic entities contained within ASC Topic 480 with a scope exception and does not impact the accounting for these mandatorily redeemable instruments. ASU 2017-11 is required to be adopted for annual periods beginning after December 15, 2019. This standard is effective for the Company on January 1, 2020. The Company is currently assessing the impact of this standard on our financial condition and results of operations. In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842) (“ASU 2016-02”), which requires an entity to recognize assets and liabilities arising from a lease for both financing and operating leases on their balance sheet date. ASU 2016-02 is effective for fiscal years beginning after December 15, 2018. In July 2018, an amendment was made that allows companies the option of using the effective date of the new standard as the initial application date (at the beginning of the period in which the new standard is adopted, rather than at the beginning of the earliest comparative period). This update includes a short-term lease exception for leases with a term of 12 months or less, in which a lessee can make an accounting policy election not to recognize the associated lease assets and lease liabilities on its balance sheet. Additionally, in March 2019, the FASB issued ASU 2019-01 (“ASU No. 2019-01”). ASU No. 2019-01 clarifies the transition guidance related to interim disclosures provided in the year of adoption. Lessees will continue to differentiate between finance leases (previously referred to as capital leases) and operating leases, using classification criteria that are substantially similar to the previous guidance. For lessees, the recognition, measurement, and presentation of expenses and cash flows arising from a lease did not significantly change from previous U.S. GAAP. The modified retrospective method includes several optional practical expedients that entities may elect to apply, as well as transition guidance specific to nonstandard leasing transactions. The Company has completed its assessment of the impact ASU 2016-02 will have on its financial position, results of operations, and related footnotes. The Company elected to utilize the available package of practical expedients permitted under the transition guidance within the new standard, which does not require the reassessment of the following: i) whether existing or expired arrangements are or contain a lease, ii) the lease classification of existing or expired leases, and iii) whether previous initial direct costs would qualify for capitalization under the new lease standard. Additionally, the Company made an accounting policy election to keep leases with an initial term of 12 months or less off of its balance sheet. The Company’s assessment included identifying the Company’s lease population, assessing significant leases under the new guidance and identifying changes to processes and controls. The adoption of the new standard will result in the recognition of right-of-use assets and lease liabilities of approximately $476 and $480, respectively, on the Company’s consolidated balance sheet. The adoption of the new standard will not have a material impact on the Company’s consolidated statement of operations or its liquidity.

SUMMARY OF SIGNIFICANT ACCOUN_3

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Tables)	12 Months Ended
	Dec. 31, 2019
Accounting Policies [Abstract]
Schedule of Property, Plant and Equipment	Depreciation expense is recognized using the straight-line method over the estimated useful life of each asset as follows: Estimated useful life Laboratory equipment 5 years Furniture and fixtures 5 years Computer and office equipment 3 years Equipment, net consisted of the following (in thousands): December 31, 2019 2018 Laboratory equipment $ 218 $ 220 Furniture and fixtures — — Computer and office equipment 58 14 Equipment 276 234 Less: accumulated depreciation (112) (100) Total Equipment, net $ 164 $ 134

FAIR VALUE MEASUREMENTS (Tables

FAIR VALUE MEASUREMENTS (Tables)	12 Months Ended
	Dec. 31, 2019
Fair Value Disclosures [Abstract]
Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis	The following tables present information about the Company’s financial assets and liabilities measured at fair value on a recurring basis and indicate the level of the fair value hierarchy used to determine such fair values: Fair value measurements at December 31, 2019 using: Level 1 Level 2 Level 3 Total Assets: Money market funds $ 24,157 $ — $ — $ 24,157 Total $ 24,157 $ — $ — $ 24,157 Liabilities: Derivative liabilities $ — $ — $ 16 $ 16 Total $ — $ — $ 16 $ 16 Fair value measurements at December 31, 2018 using: Level 1 Level 2 Level 3 Total Liabilities: Derivative liabilities $ — $ — $ 4,023 $ 4,023 Total $ — $ — $ 4,023 $ 4,023
Schedule of Fair Value Measurement Inputs	The following table presents the key inputs of the tranche rights derivative liabilities, which were extinguished in August 2019: December 31, 2019 2018 Risk-free interest rate 0.0 % 2.6 % Expected term (in years) 0.0 2.0 Expected volatility 0.0 % 65.0 % Expected dividend yield 0.0 % 0.0 %
Reconciliation of Fair Value Liabilities	Derivative liabilities Balance - December 31, 2017 $ 8 Issuance of series B preferred stock tranche right 4,000 Change in fair value 15 Balance - December 31, 2018 4,023 Change in fair value 6,393 Exercise of series B preferred stock tranche right (10,400) Balance - December 31, 2019 $ 16

PROPERTY AND EQUIPMENT (Tables)

PROPERTY AND EQUIPMENT (Tables)	12 Months Ended
	Dec. 31, 2019
Property, Plant and Equipment [Abstract]
Schedule of Property, Plant and Equipment	Depreciation expense is recognized using the straight-line method over the estimated useful life of each asset as follows: Estimated useful life Laboratory equipment 5 years Furniture and fixtures 5 years Computer and office equipment 3 years Equipment, net consisted of the following (in thousands): December 31, 2019 2018 Laboratory equipment $ 218 $ 220 Furniture and fixtures — — Computer and office equipment 58 14 Equipment 276 234 Less: accumulated depreciation (112) (100) Total Equipment, net $ 164 $ 134

ACCRUED EXPENSES (Tables)

ACCRUED EXPENSES (Tables)	12 Months Ended
	Dec. 31, 2019
Payables and Accruals [Abstract]
Schedule of Accrued Expenses	Accrued expenses consisted of the following (in thousands): ​ December 31, 2019 2018 Contracted research services $ 434 $ — Payroll and related expenses 1,182 357 Professional and consulting fees 984 95 Legal fees 299 — Total accrued expenses $ 2,899 $ 452

CONVERTIBLE PREFERRED STOCK (Ta

CONVERTIBLE PREFERRED STOCK (Tables)	12 Months Ended
	Dec. 31, 2019
Temporary Equity Disclosure [Abstract]
Schedule of Preferred Stock	As of each balance sheet date, the preferred stock consisted of the following: December 31, 2019 Shares authorized Shares issued and outstanding Carrying value Liquidation preference Common stock issuable upon conversion Series A preferred stock 22,533,945 22,501,503 $ 22,357 $ 22,502 7,461,168 Series B preferred stock 22,917,726 22,917,726 93,479 87,225 7,599,178 Series C preferred stock 19,420,124 19,420,124 84,737 85,000 6,439,424 64,871,795 64,839,353 $ 200,573 $ 194,727 21,499,770 December 31, 2018 Shares Shares Carrying Liquidation Common stock issuable upon conversion Series A convertible preferred stock 22,533,945 22,501,503 $ 22,357 $ 22,502 7,461,168 Series B convertible preferred stock 22,333,144 11,166,572 38,413 42,500 3,702,677 44,867,089 33,668,075 $ 60,770 $ 65,002 11,163,845

STOCK-BASED COMPENSATION (Table

STOCK-BASED COMPENSATION (Tables)	12 Months Ended
	Dec. 31, 2019
Share-based Payment Arrangement [Abstract]
Schedule of Stock Options Valuation Assumptions	The assumptions that the Company used to determine the grant-date fair value of options granted to employees and directors were as follows, presented on a weighted-average basis: December 31, 2019 2018 Risk-free interest rate 1.68 % 2.87 % Expected term (in years) 6.0 6.1 Expected volatility 62.2 % 58.4 % Expected dividend yield 0 % 0 % The assumptions that the Company used to determine the fair value of options granted to non-employees were as follows, presented on a weighted-average basis: December 31, 2019 2018 Risk-free interest rate 1.68 % 2.87 % Expected term (in years) 6.0 9.7 Expected volatility 62.2 % 58.4 % Expected dividend yield 0 % 0 %
Schedule of Stock Option Activity	The following table summarizes option activity under the 2017 Plan since December 31, 2018 (in thousands, except share and per share amounts): Options Weighted Average Exercise Price Weighted Average Remaining Life (in Years) Intrinsic Value (in thousands) Outstanding December 31, 2018 47,735 $ 0.66 9.5 $ 121 Granted 2,330,739 $ 8.18 Outstanding December 31, 2019 2,378,474 $ 8.03 9.7 $ 6,722 Options vested or expected to vest as of December 31, 2019 2,378,474 $ 8.03 9.7 $ 6,722 Options exercisable as of December 31, 2019 111,633 $ 4.98 9.2 $ 656
Schedule of Restricted Stock Activity	The following table summarizes restricted stock activity since December 31, 2017: Number of shares Weighted average grant date fair value Unvested restricted common stock as of December 31, 2017 91,680 $ 0.30 Granted 92,497 $ 0.72 Vested (51,532) $ 0.30 Unvested restricted common stock as of December 31, 2018 132,645 $ 0.51 Granted 62,988 $ 5.22 Vested (195,633) $ 5.94 Unvested restricted common stock as of December 31, 2019 — $ —
Schedule of Stock-Based Compensation	The Company recorded stock-based compensation expense in the following expense categories of its consolidated statements of operations (in thousands): December 31, 2019 2018 Research and development $ 3,171 $ 62 General and administrative 472 1 $ 3,643 $ 63

INCOME TAXES (Tables)

INCOME TAXES (Tables)	12 Months Ended
	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Schedule of Income Tax Rate Reconciliation	A reconciliation of income taxes computed using the U.S. federal statutory rate to that reflected in operations as of December 31, 2019 and 2018, respectively, is as follows: December 31, 2019 2018 U.S. federal statutory income tax rate 21.0 % 21.0 % State and local taxes, net of federal benefit 1.6 % 5.1 % Permanent differences (4.2) % 0.0 % Research and development credits 1.6 % 3.7 % Change in valuation allowance (19.8) % (29.8) % Other (0.2) % 0.0 % Effective income tax rate 0.0 % 0.0 %
Schedule of Deferred Tax Assets	The tax effects of temporary differences that gave rise to significant portions of the deferred tax assets were as follows (in thousands): Tax year ended December 31, 2019 2018 Deferred tax assets (liabilities): Net operating loss carryforwards $ 9,512 $ 2,904 Research and development tax credits 1,014 459 Accrual to cash adjustment — 657 Accruals and other 280 — Stock-based compensation 196 — Total deferred tax assets 11,002 4,020 Valuation Allowance (10,995) (4,010) Subtotal 7 10 Net fixed assets (7) (10) Net deferred tax assets $ — $ —

NET LOSS PER SHARE (Tables)

NET LOSS PER SHARE (Tables)	12 Months Ended
	Dec. 31, 2019
Earnings Per Share [Abstract]
Schedule of Computation of Net Loss per Share	The following table summarizes the computation of basic and diluted net loss per share attributable to common stockholders of the Company (in thousands, except share and per share amounts): December 31, 2019 2018 Net loss attributable to common stockholders $ (35,258) $ (8,931) Weighted average common shares outstanding, basic and diluted 2,075,753 2,018,623 Net loss per share, basic and diluted $ (16.99) $ (4.42)
Schedule of Antidilutive Securities Excluded from Computation of Net Loss per Share	The Company excluded the following potential common shares, presented based on amounts outstanding at each period end, from the computation of diluted net loss per share attributable to common stockholders for the periods indicated because including them would have had an anti-dilutive effect: December 31, 2019 2018 Options to purchase common stock 2,378,474 47,735 Unvested restricted stock — 132,645 Preferred stock (as converted to common stock) 21,499,770 11,163,838 Warrants to purchase shares of series A preferred stock (as converted to common stock) 10,757 10,757 23,889,001 11,354,975

COMMITMENTS AND CONTINGENCIES (

COMMITMENTS AND CONTINGENCIES (Tables)	12 Months Ended
	Dec. 31, 2019
Commitments and Contingencies Disclosure [Abstract]
Schedule of Future Minimum Lease Payments	The Company is obligated to make minimum lease payments under the facility lease as follows (in thousands): Years Ending December 31, 2020 $ 223 2021 228 2022 77 2023 — Total $ 528

SELECTED QUARTERLY FINANCIAL _2

SELECTED QUARTERLY FINANCIAL DATA (UNAUDITED) (Tables)	12 Months Ended
	Dec. 31, 2019
Quarterly Financial Information Disclosure [Abstract]
Schedule of Quarterly Financial Information	The following table contains quarterly financial information for 2019 and 2018. The Company believes that the following information reflects all normal recurring adjustments necessary for a fair presentation of the information for the periods presented. The operating results for any quarter are not necessarily indicative of results for any future period. 2019 March 31, June 30, September 30, December 31, Total (in thousands, except per share data) Revenue $ — $ — $ — $ — $ — Total operating expenses 3,841 6,999 8,148 10,344 29,332 Loss from operations (3,841) (6,999) (8,148) (10,344) (29,332) Net loss attributable to common stockholders (3,828) (12,287) (9,268) (9,875) (35,258) Net loss per share attributable to common stockholders, basic and diluted $ (1.87) $ (5.99) $ (4.50) $ (4.63) $ (16.99) 2018 March 31, June 30, September 30, December 31, Total (in thousands, except per share data) Revenue $ — $ — $ — $ — $ — Total operating expenses 1,605 1,914 2,339 3,046 8,904 Loss from operations (1,605) (1,914) (2,339) (3,046) (8,904) Net loss attributable to common stockholders (1,592) (1,913) (2,360) (3,066) (8,931) Net loss per share attributable to common stockholders, basic and diluted $ (0.80) $ (0.95) $ (1.16) $ (1.51) $ (4.42)

NATURE OF BUSINESS AND BASIS _2

NATURE OF BUSINESS AND BASIS OF PRESENTATION (Details) $ in Thousands	Feb. 03, 2020USD ($)shares	Jan. 21, 2020	Dec. 31, 2019USD ($)	Sep. 30, 2019USD ($)	Jun. 30, 2019USD ($)	Mar. 31, 2019USD ($)	Dec. 31, 2018USD ($)	Sep. 30, 2018USD ($)	Jun. 30, 2018USD ($)	Mar. 31, 2018USD ($)	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)
Subsidiary, Sale of Stock [Line Items]
Net loss			$ 9,875	$ 9,268	$ 12,287	$ 3,828	$ 3,066	$ 2,360	$ 1,913	$ 1,592	$ 35,258	$ 8,931
Accumulated deficit			$ 50,970				$ 15,712				$ 50,970	$ 15,712
Subsequent Event
Subsidiary, Sale of Stock [Line Items]
Reverse stock split		3.01581
Subsequent Event | IPO
Subsidiary, Sale of Stock [Line Items]
Number of shares sold | shares	12,174,263
Number of shares issued, options exercised | shares	1,587,947
Gross proceeds	$ 231,311
Proceeds from stock issuance, net	$ 212,429
Number of shares issued upon conversion | shares	21,499,770

SUMMARY OF SIGNIFICANT ACCOUN_4

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Narrative (Details)	12 Months Ended
	Dec. 31, 2019USD ($)segment	Dec. 31, 2018USD ($)	Jan. 01, 2020USD ($)
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Restricted cash	$ 55,000	$ 0
Deferred offering costs	$ 2,303,000	0
Number of operating segments | segment	1
Other comprehensive income	$ 0	$ 0
Forecast | ASU 2016-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Right-of-use asset			$ 476,000
Lease liability			$ 480,000

SUMMARY OF SIGNIFICANT ACCOUN_5

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Schedule of Property, Plant and Equipment (Details)	12 Months Ended
	Dec. 31, 2019
Laboratory equipment
Property, Plant and Equipment [Line Items]
Estimated useful life	5 years
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Estimated useful life	5 years
Computer and office equipment
Property, Plant and Equipment [Line Items]
Estimated useful life	3 years

FAIR VALUE MEASUREMENTS - Sched

FAIR VALUE MEASUREMENTS - Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis (Details) - Recurring - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Assets:
Money market funds	$ 24,157
Total	24,157
Liabilities:
Derivative liabilities	16	$ 4,023
Total	16	4,023
Level 1
Assets:
Money market funds	24,157
Total	24,157
Liabilities:
Derivative liabilities	0	0
Total	0	0
Level 2
Assets:
Money market funds	0
Total	0
Liabilities:
Derivative liabilities	0	0
Total	0	0
Level 3
Assets:
Money market funds	0
Total	0
Liabilities:
Derivative liabilities	16	4,023
Total	$ 16	$ 4,023

FAIR VALUE MEASUREMENTS - Narra

FAIR VALUE MEASUREMENTS - Narrative (Details) - USD ($) $ in Thousands	1 Months Ended	8 Months Ended	12 Months Ended
	Aug. 31, 2019	Aug. 31, 2019	Dec. 31, 2019	Dec. 31, 2018	Mar. 31, 2017
Series B
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative liabilities				$ 4,000
Issuance of convertible preferred stock, net (in shares)	11,294,902		11,751,154	11,166,572
Change in fair value		$ 6,393
Series A
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative liabilities					$ 500
Issuance of convertible preferred stock, net (in shares)				10,000,000
Number of shares into which the warrant may be converted					32,442

FAIR VALUE MEASUREMENTS - Sch_2

FAIR VALUE MEASUREMENTS - Schedule of Fair Value Measurement Inputs (Details)	Dec. 31, 2019	Dec. 31, 2018
Risk-free interest rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative liability measurement input	0	0.026
Expected term (in years)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative liability measurement input	0	2
Expected volatility
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative liability measurement input	0	0.650
Expected dividend yield
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative liability measurement input	0	0

FAIR VALUE MEASUREMENTS - Recon

FAIR VALUE MEASUREMENTS - Reconciliation of Fair Value Liabilities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Derivative liabilities, beginning balance	$ 4,023	$ 8
Issuance of series B preferred stock tranche right		4,000
Change in fair value	6,393	15
Exercise of series B preferred stock tranche right	(10,400)
Derivative liabilities, ending balance	$ 16	$ 4,023

PROPERTY AND EQUIPMENT (Details

PROPERTY AND EQUIPMENT (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Property, Plant and Equipment [Line Items]
Equipment	$ 276	$ 234
Less: accumulated depreciation	(112)	(100)
Total Equipment, net	164	134
Depreciation expense	47	44
Laboratory equipment
Property, Plant and Equipment [Line Items]
Equipment	218	220
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Equipment	0	0
Computer and office equipment
Property, Plant and Equipment [Line Items]
Equipment	$ 58	$ 14

ACCRUED EXPENSES (Details)

ACCRUED EXPENSES (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Payables and Accruals [Abstract]
Contracted research services	$ 434	$ 0
Payroll and related expenses	1,182	357
Professional and consulting fees	984	95
Legal fees	299	0
Total accrued expenses	$ 2,899	$ 452

CONVERTIBLE PREFERRED STOCK - N

CONVERTIBLE PREFERRED STOCK - Narrative (Details)	1 Months Ended						12 Months Ended
	Nov. 30, 2019USD ($)$ / sharesshares	Jul. 31, 2019USD ($)$ / sharesshares	Dec. 31, 2018USD ($)$ / sharesshares	Aug. 31, 2018USD ($)$ / sharesshares	Dec. 31, 2017shares	Mar. 31, 2017USD ($)$ / sharesshares	Dec. 31, 2019USD ($)director$ / sharesshares	Dec. 31, 2018USD ($)$ / sharesshares
Temporary Equity [Line Items]
Convertible preferred stock, shares authorized			44,867,089				64,871,795	44,867,089
Convertible preferred stock, par value (in dollars per share) | $ / shares			$ 0.0001				$ 0.0001	$ 0.0001
Number of directors | director							2
Conversion terms, trigger stock price (in dollars per share) | $ / shares							$ 4.50
Conversion terms, trigger gross proceeds | $							$ 75,000,000
Preferred stock dividends | $							$ 0	$ 0
Series A
Temporary Equity [Line Items]
Convertible preferred stock, shares authorized			22,533,945				22,533,945	22,533,945
Number of shares sold				5,000,000	5,000,000	5,000,000
Stock price (in dollars per share) | $ / shares			$ 1	$ 1			$ 1	$ 1
Proceeds from stock issuance, net | $				$ 4,899,000		$ 4,924,000
Stock issuance costs | $				$ 101,000		$ 76,000
Number of shares issued upon conversion						2,501,503
Derivative liabilities | $						$ 500,000
Stock price, post stock split (in dollars per share) | $ / shares			$ 3.02				$ 3.02	$ 3.02
Number of shares issued upon conversion			1				1	1
Series B
Temporary Equity [Line Items]
Convertible preferred stock, shares authorized			22,333,144				22,917,726	22,333,144
Number of shares sold		456,252	11,166,572	11,294,902
Stock price (in dollars per share) | $ / shares		$ 3.81	$ 3.81			$ 1	$ 3.81	$ 3.81
Proceeds from stock issuance, net | $		$ 1,736,000	$ 42,414,000
Stock issuance costs | $			86,000
Derivative liabilities | $			$ 4,000,000					$ 4,000,000
Stock price, post stock split (in dollars per share) | $ / shares			$ 11.48				$ 11.48	$ 11.48
Number of shares issued upon conversion			1				1	1
Series C
Temporary Equity [Line Items]
Convertible preferred stock, shares authorized							19,420,124
Number of shares sold	19,420,124
Stock price (in dollars per share) | $ / shares	$ 4.38						$ 4.38
Proceeds from stock issuance, net | $	$ 84,737,000
Stock issuance costs | $	$ 263,000
Stock price, post stock split (in dollars per share) | $ / shares							$ 13.20
Number of shares issued upon conversion							1
Developmental milestone | Series A
Temporary Equity [Line Items]
Stock price (in dollars per share) | $ / shares						$ 1
Proceeds from stock issuance, net | $						$ 5,000,000
Number of shares reserved for future issuance						5,000,000
Provision of occurrence before December 15, 2018 | Series A
Temporary Equity [Line Items]
Stock price (in dollars per share) | $ / shares				$ 1
Number of shares reserved for future issuance				5,000,000
Proceeds from stock issuance, gross | $				$ 5,000,000
Regulatory milestone | Series B
Temporary Equity [Line Items]
Stock price (in dollars per share) | $ / shares			$ 3.81					$ 3.81
Proceeds from stock issuance, net | $								$ 42,500,000
Number of shares reserved for future issuance			11,166,572					11,166,572
Series B tranche right provision | Series B
Temporary Equity [Line Items]
Stock price (in dollars per share) | $ / shares		$ 3.81
Number of shares reserved for future issuance		128,330

CONVERTIBLE PREFERRED STOCK - S

CONVERTIBLE PREFERRED STOCK - Schedule of Preferred Stock (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Temporary Equity [Line Items]
Convertible preferred stock, shares authorized	64,871,795	44,867,089
Convertible preferred stock, shares issued	64,839,353	33,668,075
Convertible preferred stock, shares outstanding	64,839,353	33,668,075	12,501,503
Carrying value	$ 200,573	$ 60,770	$ 12,458
Convertible preferred stock, liquidation preference	$ 194,727	$ 65,002
Common stock issuable upon conversion (in shares)	21,499,770	11,163,845
Series A
Temporary Equity [Line Items]
Convertible preferred stock, shares authorized	22,533,945	22,533,945
Convertible preferred stock, shares issued	22,501,503	22,501,503
Convertible preferred stock, shares outstanding	22,501,503	22,501,503
Carrying value	$ 22,357	$ 22,357
Convertible preferred stock, liquidation preference	$ 22,502	$ 22,502
Common stock issuable upon conversion (in shares)	7,461,168	7,461,168
Series B
Temporary Equity [Line Items]
Convertible preferred stock, shares authorized	22,917,726	22,333,144
Convertible preferred stock, shares issued	22,917,726	11,166,572
Convertible preferred stock, shares outstanding	22,917,726	11,166,572
Carrying value	$ 93,479	$ 38,413
Convertible preferred stock, liquidation preference	$ 87,225	$ 42,500
Common stock issuable upon conversion (in shares)	7,599,178	3,702,677
Series C
Temporary Equity [Line Items]
Convertible preferred stock, shares authorized	19,420,124
Convertible preferred stock, shares issued	19,420,124
Convertible preferred stock, shares outstanding	19,420,124
Carrying value	$ 84,737
Convertible preferred stock, liquidation preference	$ 85,000
Common stock issuable upon conversion (in shares)	6,439,424

COMMON STOCK (Details)

COMMON STOCK (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Jan. 03, 2020
Class of Stock [Line Items]
Common stock, shares authorized	80,000,000	57,803,522
Common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Common stock, number of shares reserved	24,027,604	12,785,541
Common stock dividends	$ 0	$ 0
Subsequent Event
Class of Stock [Line Items]
Common stock, shares authorized			500,000,000
Common stock, par value (in dollars per share)			$ 0.0001
Total shares authorized			510,000,000
Preferred stock, shares authorized			10,000,000
Preferred stock, par value (in dollars per share)			$ 0.0001

STOCK-BASED COMPENSATION - Narr

STOCK-BASED COMPENSATION - Narrative (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended	12 Months Ended
	Jun. 30, 2019	Dec. 31, 2019	Dec. 31, 2018	Jan. 14, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expiration period of incentive plan		10 years
Vesting period		4 years
Weighted-average grant-date fair value per share of options granted (in dollars per share)	$ 4.13	$ 4.82	$ 0.39
Fair value of options vested		$ 319	$ 7
Stock-based compensation expense		$ 3,643	$ 63
Exercise Price (in dollars per share)	$ 3.20
Common stock, number of shares reserved		24,027,604	12,785,541
2017 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized		8,336,573	1,795,102
Number of shares available for grant		138,603	1,563,187
2020 Plan | Subsequent Event
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock, number of shares reserved				6,665,891
Increase of authorized shares, percent of common stock outstanding				4.00%
2020 ESPP | Subsequent Event
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock, number of shares reserved				326,364
Increase of authorized shares, percent of common stock outstanding				1.00%
Unvested restricted stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period		3 years
Fair value of restricted stock vested		$ 420	$ 40
Stock-based compensation expense		1,973	53
Unrecognized compensation cost		$ 11,315	$ 335
Unrecognized compensation cost, recognition period		3 years 6 months	3 years 3 months 18 days
First anniversary
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage		25.00%
Thereafter
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period		3 years
Person possessing less than 10% of voting power
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum percent of fair market value of common stock		100.00%
Person possessing more than 10% of voting power
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum percent of fair market value of common stock		110.00%
Expiration period of incentive plan		5 years

STOCK-BASED COMPENSATION - Sche

STOCK-BASED COMPENSATION - Schedule of Stock Options Valuation Assumptions (Details)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Employees
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rate	1.68%	2.87%
Expected term (in years)	6 years	6 years 1 month 6 days
Expected volatility	62.20%	58.40%
Expected dividend yield	0.00%	0.00%
Non-employees
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rate	1.68%	2.87%
Expected term (in years)	6 years	9 years 8 months 12 days
Expected volatility	62.20%	58.40%
Expected dividend yield	0.00%	0.00%

STOCK-BASED COMPENSATION - Sc_2

STOCK-BASED COMPENSATION - Schedule of Stock Option Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Options
Outstanding, beginning balance (in shares)	47,735
Granted (in shares)	2,330,739
Outstanding, ending balance (in shares)	2,378,474	47,735
Options vested or expected to vest (in shares)	2,378,474
Options exercisable (in shares)	111,633
Weighted Average Exercise Price
Outstanding, beginning balance (in dollars per share)	$ 0.66
Granted (in dollars per share)	8.18
Outstanding, ending balance (in dollars per share)	8.03	$ 0.66
Options vested or expected to vest (in dollars per share)	8.03
Options exercisable (in dollars per share)	$ 4.98
Weighted Average Remaining Life and Intrinsic Value
Options outstanding, remaining life	9 years 8 months 12 days	9 years 6 months
Options vested or expected to vest, remaining life	9 years 8 months 12 days
Options exercisable, remaining life	9 years 2 months 12 days
Options outstanding, intrinsic value	$ 6,722	$ 121
Options vested or expected to vest, intrinsic value	6,722
Options exercisable, intrinsic value	$ 656

STOCK-BASED COMPENSATION - Sc_3

STOCK-BASED COMPENSATION - Schedule of Restricted Stock Activity (Details) - Unvested restricted stock - $ / shares	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Number of shares
Unvested restricted common stock, beginning balance (in shares)	132,645	91,680
Granted (in shares)	62,988	92,497
Vested (in shares)	(195,633)	(51,532)
Unvested restricted common stock, ending balance (in shares)	0	132,645
Weighted average grant date fair value
Unvested restricted common stock, beginning balance (in dollars per share)	$ 0.51	$ 0.30
Granted (in dollars per share)	5.22	0.72
Vested (in dollars per share)	5.94	0.30
Unvested restricted common stock, ending balance (in dollars per share)	$ 0	$ 0.51

STOCK-BASED COMPENSATION - Sc_4

STOCK-BASED COMPENSATION - Schedule of Stock-Based Compensation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation expense	$ 3,643	$ 63
Research and development
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation expense	3,171	62
General and administrative
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation expense	$ 472	$ 1

INCOME TAXES - Narrative (Detai

INCOME TAXES - Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Operating Loss Carryforwards [Line Items]
Income tax benefit	$ 0	$ 0
Increase in valuation allowance	6,985,000
Unrecognized tax benefits	0	0
Accrued interest and penalties related to uncertain tax positions	0	$ 0
Federal
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards	39,596,000
State
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards	20,075,000
Canada
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards	222,000
Research and development | Federal
Operating Loss Carryforwards [Line Items]
Tax credit carryforward	$ 1,014,000

INCOME TAXES - Schedule of Inco

INCOME TAXES - Schedule of Income Tax Rate Reconciliation (Details)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
U.S. federal statutory income tax rate	21.00%	21.00%
State and local taxes, net of federal benefit	1.60%	5.10%
Permanent differences	(4.20%)	0.00%
Research and development credits	1.60%	3.70%
Change in valuation allowance	(19.80%)	(29.80%)
Other	(0.20%)	0.00%
Effective income tax rate	0.00%	0.00%

INCOME TAXES - Schedule of Defe

INCOME TAXES - Schedule of Deferred Tax Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Deferred tax assets (liabilities):
Net operating loss carryforwards	$ 9,512	$ 2,904
Research and development tax credits	1,014	459
Accrual to cash adjustment	0	657
Accruals and other	280	0
Stock-based compensation	196	0
Total deferred tax assets	11,002	4,020
Valuation Allowance	(10,995)	(4,010)
Subtotal	7	10
Net fixed assets	(7)	(10)
Net deferred tax assets	$ 0	$ 0

NET LOSS PER SHARE - Schedule o

NET LOSS PER SHARE - Schedule of Computation of Net Loss per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Net loss	$ (9,875)	$ (9,268)	$ (12,287)	$ (3,828)	$ (3,066)	$ (2,360)	$ (1,913)	$ (1,592)	$ (35,258)	$ (8,931)
Weighted average common shares outstanding, basic and diluted									2,075,753	2,018,623
Net loss per share attributable to common stockholders, basic and diluted (in dollars per share)	$ (4.63)	$ (4.50)	$ (5.99)	$ (1.87)	$ (1.51)	$ (1.16)	$ (0.95)	$ (0.80)	$ (16.99)	$ (4.42)
Unvested restricted stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Unvested restricted common stock (in shares)	0				132,645				0	132,645	91,680

NET LOSS PER SHARE - Schedule_2

NET LOSS PER SHARE - Schedule of Antidilutive Securities Excluded from Computation of Net Loss per Share (Details) - shares	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities (in shares)	23,889,001	11,354,975
Options to purchase common stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities (in shares)	2,378,474	47,735
Unvested restricted stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities (in shares)	0	132,645
Preferred stock (as converted to common stock)
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities (in shares)	21,499,770	11,163,838
Warrants to purchase shares of series A preferred stock (as converted to common stock)
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities (in shares)	10,757	10,757

COMMITMENTS AND CONTINGENCIES -

COMMITMENTS AND CONTINGENCIES - Narrative (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2019USD ($)ft²	Dec. 31, 2018USD ($)
Commitments and Contingencies Disclosure [Abstract]
Area leased | ft²	2,357
Lease term, optional extension	3 years
Rent expense | $	$ 415	$ 36

COMMITMENTS AND CONTINGENCIES_2

COMMITMENTS AND CONTINGENCIES - Schedule of Future Minimum Lease Payments (Details) $ in Thousands	Dec. 31, 2019USD ($)
Commitments and Contingencies Disclosure [Abstract]
2020	$ 223
2021	228
2022	77
2023	0
Total	$ 528

BENEFIT PLANS (Details)

BENEFIT PLANS (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Retirement Benefits [Abstract]
Employer contribution, percent of each participant's salary	6.00%
Employer contribution amount	$ 200	$ 20

RELATED-PARTY TRANSACTIONS (Det

RELATED-PARTY TRANSACTIONS (Details) - USD ($)	1 Months Ended		12 Months Ended
	Dec. 31, 2018	Mar. 31, 2017	Dec. 31, 2019	Dec. 31, 2018
Related Party Transaction [Line Items]
Prepaids with related party			$ 916,000
Amounts due to related party	$ 1,707,000		0	$ 1,707,000
Related party expense, service fees			$ 10,411,000	$ 2,728,000
Ridgeline | Monthly service agreement
Related Party Transaction [Line Items]
Related party transaction, markup rate		10.00%
Related party transaction, monthly transaction amount	$ 950,000

SELECTED QUARTERLY FINANCIAL _3

SELECTED QUARTERLY FINANCIAL DATA (UNAUDITED) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018
Quarterly Financial Information Disclosure [Abstract]
Revenue	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0
Total operating expenses	10,344	8,148	6,999	3,841	3,046	2,339	1,914	1,605	29,332	8,904
Loss from operations	(10,344)	(8,148)	(6,999)	(3,841)	(3,046)	(2,339)	(1,914)	(1,605)	(29,332)	(8,904)
Net loss	$ (9,875)	$ (9,268)	$ (12,287)	$ (3,828)	$ (3,066)	$ (2,360)	$ (1,913)	$ (1,592)	$ (35,258)	$ (8,931)
Net loss per share attributable to common stockholders, basic and diluted (in dollars per share)	$ (4.63)	$ (4.50)	$ (5.99)	$ (1.87)	$ (1.51)	$ (1.16)	$ (0.95)	$ (0.80)	$ (16.99)	$ (4.42)

Uncategorized Items - bdtx-2019

Label	Element	Value
Restricted Cash and Cash Equivalents, Current	us-gaap_RestrictedCashAndCashEquivalentsAtCarryingValue	$ 0
Restricted Cash and Cash Equivalents, Current	us-gaap_RestrictedCashAndCashEquivalentsAtCarryingValue	$ 55,000