Axcella Health (AXLA) 10-Q 3 Aug 23 2023 Q2 Quarterly report Financial data

Cover Page

Cover Page - shares	6 Months Ended
	Jun. 30, 2023	Jul. 28, 2023
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Jun. 30, 2023
Document Transition Report	false
Entity File Number	001-38901
Entity Registrant Name	AXCELLA HEALTH INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	26-3321056
Entity Address, Address Line One	P.O. Box 1270
Entity Address, City or Town	Littleton
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	01460
City Area Code	857
Local Phone Number	320-2200
Title of 12(b) Security	Common Stock, $0.001 par value per share
Trading Symbol	AXLA
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding (in shares)		73,692,745
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	Q2
Amendment Flag	false
Entity Central Index Key	0001633070
Current Fiscal Year End Date	--12-31

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Current assets:
Cash and cash equivalents	$ 8,884	$ 17,147
Prepaid expenses and other current assets	383	876
Total current assets	9,267	18,023
Property and equipment, net	15	693
Other assets	0	211
Total assets	9,282	18,927
Current liabilities:
Accounts payable	8,395	4,707
Accrued expenses and other current liabilities	1,754	7,849
Current portion of operating lease liability	1,391	1,592
Total current liabilities	11,540	14,148
Operating lease liability	0	569
Other non-current liabilities	0	46
Total liabilities	11,540	14,763
Commitments and contingencies (Note 8)	0	0
Stockholders' equity (deficit):
Common stock, $0.001 par value; 150,000,000 shares authorized, 74,111,726 and 74,074,201 shares issued and 73,692,745 and 73,655,220 shares outstanding at June 30, 2023 and December 31, 2022, respectively	74	74
Additional paid-in capital	423,484	422,517
Treasury stock, 418,981 shares at cost	0	0
Accumulated deficit	(425,816)	(418,427)
Total stockholders' equity (deficit)	(2,258)	4,164
Total liabilities and stockholders' equity (deficit)	$ 9,282	$ 18,927

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) - $ / shares	Jun. 30, 2023	Dec. 31, 2022
Statement of Financial Position [Abstract]
Common stock, par value (USD per share)	$ 0.001	$ 0.001
Common stock authorized (in shares)	150,000,000	150,000,000
Common stock issued (in shares)	74,111,726	74,074,201
Common stock outstanding (in shares)	73,692,745	73,655,220
Treasury stock at cost (in shares)	418,981	418,981

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations and Comprehensive Loss (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Operating expenses:
Research and development	$ 1,224	$ 16,866	$ 2,657	$ 30,410
General and administrative	2,319	3,753	5,069	8,539
Total operating expenses	3,543	20,619	7,726	38,949
Loss from operations	(3,543)	(20,619)	(7,726)	(38,949)
Other (expense) income:
Interest income	132	65	272	87
Interest expense	0	(752)	0	(1,456)
Other income (expense), net	(2)	0	65	(27)
Total other income (expense), net	130	(687)	337	(1,396)
Net loss	$ (3,413)	$ (21,306)	$ (7,389)	$ (40,345)
Net loss per share, basic (USD per share)	$ (0.05)	$ (0.40)	$ (0.10)	$ (0.86)
Net loss per share, diluted (USD per share)	$ (0.05)	$ (0.40)	$ (0.10)	$ (0.86)
Weighted average common shares outstanding, basic (in shares)	73,688,558	52,616,279	73,678,881	47,052,105
Weighted average common shares outstanding, diluted (in shares)	73,688,558	52,616,279	73,678,881	47,052,105
Comprehensive loss:
Net loss	$ (3,413)	$ (21,306)	$ (7,389)	$ (40,345)
Other comprehensive income (loss):
Unrealized losses on marketable securities	0	4	0	(14)
Comprehensive loss	$ (3,413)	$ (21,302)	$ (7,389)	$ (40,359)

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022
Cash flows from operating activities:
Net loss	$ (7,389)	$ (40,345)
Adjustment to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	21	159
Share-based compensation	967	2,103
Non-cash interest expense	0	263
Gain on the sale of property and equipment	(68)	0
Non-cash lease expense	(770)	(26)
Other non-cash items	0	163
Changes in current assets and liabilities:
Prepaid expenses and other current assets	704	(146)
Accounts payable	3,689	(137)
Accrued expenses and other current liabilities	(5,915)	2,437
Net cash used in operating activities	(8,761)	(35,529)
Cash flows from investing activities:
Purchases of property and equipment	0	(202)
Proceeds from the sale of property and equipment	525	0
Proceeds from sales and maturities of marketable securities	0	20,974
Net cash provided by investing activities	525	20,772
Cash flows from financing activities:
Proceeds from issuance of common stock, net of issuance costs	0	25,456
Offering costs paid	0	(193)
Proceeds from exercise of common stock options and ESPP	0	90
Repayments of the principal portion of finance lease	(27)	(93)
Net cash (used in) provided by financing activities	(27)	25,260
Net (decrease) increase in cash and cash equivalents	(8,263)	10,503
Cash and cash equivalents, beginning of period	17,147	23,574
Cash and cash equivalents, end of period	8,884	34,077
Supplemental cash flow information:
Cash paid for interest	0	1,200
Supplemental disclosure of non-cash activities:
Obtaining a right-of-use asset in exchange for an operating lease liability	0	3,340
Purchases of property and equipment included in accounts payable	$ 0	$ 26

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Stockholders' Equity (Deficit) (Unaudited) - USD ($) $ in Thousands	Total	Common stock	Additional paid-in capital	Accumulated other comprehensive loss	Accumulated deficit
Balance at beginning of period (in shares) at Dec. 31, 2021		39,605,701
Balance at beginning of period at Dec. 31, 2021	$ 22,008	$ 40	$ 359,261	$ (52)	$ (337,241)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock, net of issuance costs (in shares)		13,321,602
Issuance of common stock, net of issuance costs	25,426	$ 13	25,413
Exercise of common stock options (in shares)		8,499
Exercise of common stock options	6		6
Vesting of restricted stock units (in shares)		59,019
Share-based compensation	1,509		1,509
Unrealized loss on marketable securities	(18)			(18)
Net loss	(19,039)				(19,039)
Balance at end of period (in shares) at Mar. 31, 2022		52,994,821
Balance at end of period at Mar. 31, 2022	29,892	$ 53	386,189	(70)	(356,280)
Balance at beginning of period (in shares) at Dec. 31, 2021		39,605,701
Balance at beginning of period at Dec. 31, 2021	22,008	$ 40	359,261	(52)	(337,241)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(40,345)
Balance at end of period (in shares) at Jun. 30, 2022		53,058,369
Balance at end of period at Jun. 30, 2022	9,298	$ 53	386,897	(66)	(377,586)
Balance at beginning of period (in shares) at Mar. 31, 2022		52,994,821
Balance at beginning of period at Mar. 31, 2022	29,892	$ 53	386,189	(70)	(356,280)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Costs incurred for the issuance of common stock	30		30
Vesting of restricted stock units (in shares)		5,797
Issuance of common stock related to ESPP (in shares)		57,751
Issuance of common stock related to ESPP	84		84
Share-based compensation	594		594
Unrealized loss on marketable securities	4			4
Net loss	(21,306)				(21,306)
Balance at end of period (in shares) at Jun. 30, 2022		53,058,369
Balance at end of period at Jun. 30, 2022	$ 9,298	$ 53	386,897	$ (66)	(377,586)
Balance at beginning of period (in shares) at Dec. 31, 2022	73,655,220	74,074,201
Balance at beginning of period at Dec. 31, 2022	$ 4,164	$ 74	422,517		(418,427)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Vesting of restricted stock units (in shares)		27,807
Share-based compensation	539		539
Net loss	(3,976)				(3,976)
Balance at end of period (in shares) at Mar. 31, 2023		74,102,008
Balance at end of period at Mar. 31, 2023	$ 727	$ 74	423,056		(422,403)
Balance at beginning of period (in shares) at Dec. 31, 2022	73,655,220	74,074,201
Balance at beginning of period at Dec. 31, 2022	$ 4,164	$ 74	422,517		(418,427)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of common stock options (in shares)	0
Net loss	$ (7,389)
Balance at end of period (in shares) at Jun. 30, 2023	73,692,745	74,111,726
Balance at end of period at Jun. 30, 2023	$ (2,258)	$ 74	423,484		(425,816)
Balance at beginning of period (in shares) at Mar. 31, 2023		74,102,008
Balance at beginning of period at Mar. 31, 2023	727	$ 74	423,056		(422,403)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Vesting of restricted stock units (in shares)		9,718
Share-based compensation	428		428
Net loss	$ (3,413)				(3,413)
Balance at end of period (in shares) at Jun. 30, 2023	73,692,745	74,111,726
Balance at end of period at Jun. 30, 2023	$ (2,258)	$ 74	$ 423,484		$ (425,816)

Condensed Consolidated Statem_4

Condensed Consolidated Statements of Stockholders' Equity (Deficit) (Unaudited) (Parenthetical) $ in Thousands	3 Months Ended
	Mar. 31, 2022 USD ($)
Statement of Stockholders' Equity [Abstract]
Stock issuance cost	$ 223
Share-based compensation	1,509
Net loss	$ (19,039)

NATURE OF BUSINESS

NATURE OF BUSINESS	6 Months Ended
	Jun. 30, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
NATURE OF BUSINESS	NATURE OF BUSINESS Company Overview Axcella Health Inc., doing business as “Axcella Therapeutics,” and subsidiaries ("Axcella," the "Company," "we" or "us") is a clinical-stage biotechnology company that was incorporated in Delaware on August 27, 2008. Since February 1, 2023, the Company has operated virtually. The Company is focused on pioneering a new approach to address the biology of complex diseases using compositions of endogenous metabolic modulators, or EMMs. The Company is subject to risks and uncertainties common to early-stage companies in the biotechnology industry, including, but not limited to, successful development of technology, obtaining additional funding, protection of proprietary technology, compliance with government regulations, risks of failure of preclinical studies, Clinical Studies and Clinical Trials, the need to obtain marketing approval for its product candidates, if required, and successfully market products, fluctuations in operating results, economic pressure impacting therapeutic pricing, dependence on key personnel, risks associated with changes in technologies, development by competitors of technological innovations and the ability to scale manufacturing to large scale production. Product candidates currently under development will require significant additional research and development efforts, including preclinical and clinical testing and any necessary regulatory approval prior to commercialization. These efforts require significant amounts of additional capital, adequate personnel and infrastructure and extensive compliance-reporting capabilities. Even if development efforts are successful, it is uncertain when, if ever, the Company will realize significant revenue from product sales. In December 2022, the Company underwent a restructuring and terminated its Phase 2b clinical trial of AXA1125 for the treatment of NASH to focus on AXA1125 for the treatment of Long COVID associated fatigue. Since then, the Company has initiated a process to explore a range of strategic alternatives to maximize stakeholder value. Under Accounting Standards Update (“ASU”) 2014-15, Presentation of Financial Statements—Going Concern (Subtopic 205-40) (“ASC 205-40”), the Company has the responsibility to evaluate whether conditions and/or events raise substantial doubt about its ability to meet its future financial obligations as they become due within one year after the date that the financial statements are issued. As of June 30, 2023, the Company had an accumulated deficit of $425.8 million, and cash and cash equivalents of $8.9 million. During the three months ended June 30, 2023, the Company incurred a loss of $3.4 million and used $8.8 million of cash in operations. Although the reorganization reduced the Company's operating expenses, the Company will need to raise additional funding to operate as it explores strategic alternatives. Management has assessed the Company’s ability to continue as a going concern in accordance with the requirements of ASC 205-40 based on the need to raise additional capital to finance its future operations, its recurring losses from operations incurred since inception, expectation of continuing operating losses for the foreseeable future, and uncertainty around the changes to the business plan. As of August 3, 2023, the issuance date of the condensed consolidated financial statements for the quarter ended June 30, 2023, the Company has concluded that there is substantial doubt about its ability to continue as a going concern for a period of one year from the date that these condensed consolidated financial statements are issued. The accompanying condensed consolidated financial statements do not include any adjustments relating to the recoverability and classification of recorded asset amounts or the amounts and classification of liabilities that might result from the outcome of this uncertainty. Accordingly, the condensed consolidated financial statements have been prepared on a basis that assumes the Company will continue as a going concern and which contemplates the realization of assets and satisfaction of liabilities and commitments in the ordinary course of business.

SUMMARY OF SIGNIFICANT ACCOUNTI

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	6 Months Ended
	Jun. 30, 2023
Accounting Policies [Abstract]
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Basis of Presentation The accompanying condensed consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (“GAAP”). Any reference in these notes to applicable guidance is meant to refer to the authoritative United States generally accepted accounting principles as found in the Accounting Standards Codification (“ASC”) and Accounting Standards Update (“ASU”) of the Financial Accounting Standards Board (“FASB”). Furthermore, the accompanying condensed consolidated financial statements are unaudited and certain information and footnote disclosures normally included in financial statements prepared in accordance with GAAP have been condensed or omitted from this report, as is permitted by such rules and regulations. The unaudited interim financial statements have been prepared on the same basis as the audited annual financial statements as of and for the year ended December 31, 2022. The accompanying interim condensed consolidated financial statements reflect all adjustments, consisting of normal recurring adjustments, necessary for the fair presentation of the Company’s financial position as of June 30, 2023, the results of its operations for the three and six months ended June 30, 2023 and 2022, its cash flows for the six months ended June 30, 2023 and 2022, and its statements of stockholders’ equity (deficit) for the three and six months ended June 30, 2023 and 2022. The results for the three and six months ended June 30, 2023 are not necessarily indicative of the results to be expected for the year ending December 31, 2023, any other interim periods, or any future year or period. These interim financial statements should be read in conjunction with the audited financial statements as of and for the year ended December 31, 2022, and the notes thereto, together with Management’s Discussion and Analysis of Financial Condition and Results of Operations, contained in the Company’s Annual Report on Form 10-K for the year ended December 31, 2022. There were no material changes to the Company's significant accounting policies and estimates as reported in its Annual Report on Form 10-K for the year ended December 31, 2022, which was filed with the SEC on March 30, 2023. Principles of Consolidation The accompanying condensed consolidated financial statements include the accounts of the Company and its wholly owned subsidiary. All intercompany accounts and transactions have been eliminated in consolidation. Use of Estimates The preparation of the condensed consolidated financial statements in accordance with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, equity, expenses and disclosure of contingent assets and liabilities at the date of the condensed consolidated financial statements and the Company’s ability to continue as a going concern. The Company bases its estimates on historical experience, known trends and other market-specific or relevant factors that it believes to be reasonable under the circumstances. On an ongoing basis, management evaluates its estimates as there are changes in circumstances, facts and experience. Actual results may differ from those estimates or assumptions. Cash and Cash Equivalents Cash and cash equivalents include cash held in banks and amounts held in interest-bearing money market accounts. Cash equivalents are carried at cost, which approximates their fair market value. The Company considers all highly liquid investments with a remaining maturity when purchased of three months or less to be cash equivalents. Concentrations of Credit Risk The Company has no off-balance sheet risk, such as foreign exchange contracts, option contracts, or other foreign hedging arrangements. Financial instruments that potentially expose the Company to concentrations of credit risk consist primarily of cash equivalents. The Company’s cash equivalents as of June 30, 2023 consisted of bank deposits and money market funds that invest in U.S. treasury securities. The Company's investment policy includes guidelines on the quality of the institutions and financial instruments and defines the allowable investments that the Company believes minimizes the exposure to concentrations of credit risk. The Company has not experienced any credit losses and does not believe that it is subject to significant credit risk. Fair Value Measurements Certain assets and liabilities of the Company are carried at fair value. 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 — Quoted prices in active markets for identical assets or liabilities. • Level 2 — Observable inputs (other than Level 1 quoted prices), such as quoted prices in active markets for similar assets or liabilities, quoted prices in markets that are not active for identical or similar assets or liabilities, or other inputs that are observable or can be corroborated by observable market data. • Level 3 — Unobservable inputs that are supported by little or no market activity that are significant to determining the fair value of the assets or liabilities, including pricing models, discounted cash flow methodologies and similar techniques. The Company’s cash equivalents are carried at fair value, determined according to the fair value hierarchy described above. The carrying values of the Company’s accounts payable and accrued expenses approximate their fair values due to the short-term nature of these liabilities. Property and Equipment Property and equipment are recorded at cost. Depreciation and amortization is calculated using the straight-line method over the estimated useful lives of the assets. Upon disposal, retirement or sale, the cost of assets disposed of and the related accumulated depreciation are removed from the accounts and any resulting gain or loss is included in the results of operations. Expenditures for repairs and maintenance that do not improve or extend the lives of the respective assets are charged to expense as incurred. Long-Lived Assets Impairment 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 and eventual disposition 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. Leases The Company determines whether a contract is, or contains, a lease at inception and classifies leases as operating or financing considering factors such as the length of the lease term, the present value of the lease payments, the nature of the asset being leased, and the potential for ownership of the asset to transfer during the lease term. Leases with terms greater than one-year are recognized on the consolidated balance sheets as right-of-use assets and lease liabilities and are measured at the present value of the fixed payments due over the expected lease term less the present value of any incentives, rebates or abatements received from the lessor. Options to extend a lease are included in the expected lease term if exercise of the option is deemed reasonably certain. Costs determined to be variable and not based on an index or rate are not included in the measurement of the lease liability and are expensed as incurred. The interest rate implicit in lease contracts is typically not readily determinable. As such, the Company utilizes the appropriate incremental borrowing rate, which is the rate incurred to borrow on a collateralized basis an amount equal to the lease payments in the same currency, for a similar term, and in a similar economic environment. The Company records expense to recognize fixed lease payments on a straight-line basis over the expected lease term. The Company has elected the practical expedient not to separate lease and non-lease components for real estate leases. Segment Information Operating segments are identified as components of an enterprise about which separate discrete financial information is available for evaluation by the Chief Executive Officer, who is the chief operating decision maker, in making decisions on how to allocate resources and assess performance. The Company operates in one reportable business segment. 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 three and six months ended June 30, 2022, the Company’s only element of other comprehensive loss was unrealized gains (losses) on marketable securities. For the three and six months ended June 30, 2023, there were no elements of other comprehensive loss. Net Loss Per Share Basic net loss per share attributable to common stockholders is calculated by dividing net loss by the weighted average shares outstanding during the period. Diluted net income (loss) per share is calculated by adjusting weighted average shares outstanding for the dilutive effect of common stock equivalents outstanding for the period. All common stock equivalents have been excluded from the calculation of diluted net loss per share, as their effect would be anti-dilutive for all periods presented. Newly Adopted Accounting Pronouncements In June 2016, the FASB issued ASU 2016-13, Financial Instruments – Credit Losses (Topic 326) . The new standard adjusts the accounting for assets held at amortized cost basis, including marketable securities accounted for as available-for-sale. The standard eliminates the probable initial recognition threshold and requires an entity to reflect its current estimate of all expected credit losses. The allowance for credit losses is a valuation account that is deducted from the amortized cost basis of the financial assets to present the net amount expected to be collected. The adoption of this standard on January 1, 2023 did not have a material impact on its condensed consolidated financial statements.

FAIR VALUE MEASUREMENTS

FAIR VALUE MEASUREMENTS	6 Months Ended
	Jun. 30, 2023
Fair Value Disclosures [Abstract]
FAIR VALUE MEASUREMENTS	FAIR VALUE MEASUREMENTS The following tables present the Company’s assets that are measured at fair value on a recurring basis and indicate the level within the fair value hierarchy (in thousands): Fair Value Measurements at June 30, 2023 using: Level 1 Level 2 Level 3 Total Assets: Cash equivalents: Money market funds $ 8,726 $ — $ — $ 8,726 Total $ 8,726 $ — $ — $ 8,726 Fair Value Measurements at December 31, 2022 using: Level 1 Level 2 Level 3 Total Assets: Cash equivalents: Money market funds $ 14,649 $ — $ — $ 14,649 Total $ 14,649 $ — $ — $ 14,649 As of June 30, 2023 and December 31, 2022, the Company’s cash equivalents were invested in money market funds and were valued based on Level 1 inputs. During the three and six months ended June 30, 2023 and 2022, there were no transfers between Level 1, Level 2 and Level 3.

PROPERTY AND EQUIPMENT

PROPERTY AND EQUIPMENT	6 Months Ended
	Jun. 30, 2023
Property, Plant and Equipment [Abstract]
PROPERTY AND EQUIPMENT	PROPERTY AND EQUIPMENT Property and equipment consist of the following (in thousands): June 30, December 31, Laboratory equipment $ — $ 3,506 Leasehold improvements — 564 Office and computer equipment 87 303 Furniture and fixtures — 122 Property and equipment 87 4,495 Less: accumulated depreciation and amortization (72) (3,802) Property and equipment, net $ 15 $ 693 Depreciation and amortization expense was nominal for the three and six months ended June 30, 2023, and $0.1 million and $0.2 million for the three and six months ended June 30, 2022.

ACCRUED EXPENSES AND OTHER CURR

ACCRUED EXPENSES AND OTHER CURRENT LIABILITIES	6 Months Ended
	Jun. 30, 2023
Payables and Accruals [Abstract]
ACCRUED EXPENSES AND OTHER CURRENT LIABILITIES	ACCRUED EXPENSES AND OTHER CURRENT LIABILITIES Accrued expenses and other current liabilities consisted of the following (in thousands): June 30, December 31, Accrued employee compensation and benefits $ 470 $ 808 Accrued external research and development expenses 843 4,791 Accrued professional fees 441 824 Accrued employee termination benefits — 1,221 Other — 205 Total accrued expenses and other current liabilities $ 1,754 $ 7,849 During the six months ended June 30, 2023, the Company paid $1.2 million in employee termination benefits related to the December 2022 reduction-in-force.

STOCKHOLDERS' EQUITY (DEFICIT)

STOCKHOLDERS' EQUITY (DEFICIT)	6 Months Ended
	Jun. 30, 2023
Equity [Abstract]
STOCKHOLDERS' EQUITY (DEFICIT)	STOCKHOLDERS' EQUITY (DEFICIT) 2019 Stock Option and Incentive Plan The 2019 Stock Option and Incentive Plan (the "2019 Plan") was approved by the Company's board of directors on April 29, 2019. The 2019 Plan provides for the grant of incentive stock options, nonqualified stock options, stock appreciation rights, restricted stock units, restricted stock awards, unrestricted stock awards and cash-based awards to the Company's officers, employees, directors and consultants. Awards under the 2019 plan generally vest ratably over the vesting period (3-4 years) and have a maximum term of 10 years. The number of shares initially reserved for issuance under the 2019 Plan is 905,000, which was increased on January 1, 2020 and will be increased 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 committee of the board of directors. The number of options available for future grant under the 2019 Plan was 6,407,936 as of June 30, 2023. 2019 Employee Stock Purchase Plan The 2019 Employee Stock Purchase Plan (the "2019 ESPP") was approved by the Company's board of directors on April 29, 2019. A total of 237,181 shares of common stock were initially reserved for issuance under this plan, which was cumulatively increased on January 1, 2020 and will be increased 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 committee of the board of directors. The number of shares available for future issuance under the 2019 ESPP was 935,186 shares as of June 30, 2023. Stock-Based Compensation Expense In connection with all share-based payment awards, total stock-based compensation expense recognized was as follows (in thousands): Three Months Ended Six Months Ended 2023 2022 2023 2022 Research and development $ 97 $ 275 $ 266 $ 841 General and administrative 331 319 701 1,262 Total stock-based compensation expense $ 428 $ 594 $ 967 $ 2,103 Fair Value of Stock Options The fair value of stock option awards was estimated using the Black-Scholes option-pricing model. The expected term of these awards was determined using the simplified method, which uses the midpoint between the vesting date and the contractual term. The risk-free interest rate was determined by reference to the U.S. Treasury yield curve for time periods approximately equal to the remaining contractual term of the stock awards. The expected dividend was zero as the Company had not paid any dividends on its common stock. Finally, as the Company does not have long-term trading history of its common stock, the expected volatility was derived from the average historical stock volatilities of several public companies within the industry that the Company considers to be comparable to the Company's business over a period equivalent to the expected term of the stock-based awards. The Black-Scholes option pricing model assumptions are included in the table below. No options were granted during the three months ended June 30, 2023. Three Months Ended Six Months Ended 2023 2022 2023 2022 Risk-free interest rate — 2.89 % 3.95 % 2.01 % Expected option life (in years) — 5.75 6.11 6.08 Expected dividend yield — — % — % — % Expected volatility — 95.3 % 90.1 % 91.9 % Stock Option Activity The following table summarizes the Company’s stock option activity for the six months ended June 30, 2023: Number of Shares Weighted Weighted Intrinsic Outstanding as of January 1, 2023 6,536,977 $ 5.05 Granted 611,500 0.68 Exercised — — Canceled (1,746,381) 4.22 Outstanding as of June 30, 2023 5,402,096 $ 4.82 6.44 $ — Exercisable as of June 30, 2023 3,995,701 $ 5.66 5.61 $ — Vested or expected to vest as of June 30, 2023 5,402,096 $ 4.82 6.44 $ — No options were exercised during the six months ended June 30, 2023. The weighted-average grant date fair value of the options granted during the six months ended June 30, 2023 and 2022 was $0.52 and $1.09 per share, respectively. As of June 30, 2023, there was $2.2 million of unrecognized compensation expense that is expected to be recognized over a weighted-average period of approximately 1.9 years. Restricted Stock Units The fair values of restricted stock units are based on the market value of the Company's common stock on the date of grant. The following table summarizes the Company's restricted stock unit activity for the six months ended June 30, 2023: Number of Shares Weighted Average Outstanding as of January 1, 2023 75,233 $ 5.04 Granted — — Vested (37,525) 3.88 Forfeited (9,375) 5.00 Outstanding as of June 30, 2023 28,333 $ 6.59

NET LOSS PER SHARE

NET LOSS PER SHARE	6 Months Ended
	Jun. 30, 2023
Earnings Per Share [Abstract]
NET LOSS PER SHARE	NET LOSS PER SHARE Basic and diluted net loss per share attributable to common stockholders was calculated as follows (in thousands, except share and per share amounts): Three Months Ended Six Months Ended 2023 2022 2023 2022 Numerator: Net loss $ (3,413) $ (21,306) $ (7,389) $ (40,345) Denominator: Weighted average common shares outstanding, basic and diluted 73,688,558 52,616,279 73,678,881 47,052,105 Net loss per share, basic and diluted $ (0.05) $ (0.40) $ (0.10) $ (0.86) 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: Six Months Ended 2023 2022 Options to purchase common stock 5,402,096 7,790,334 Unvested restricted stock units 28,333 182,593 Shares issuable under employee stock purchase plan — 65,790 5,430,429 8,038,717

COMMITMENTS AND CONTINGENCIES

COMMITMENTS AND CONTINGENCIES	6 Months Ended
	Jun. 30, 2023
Commitments and Contingencies Disclosure [Abstract]
COMMITMENTS AND CONTINGENCIES	COMMITMENTS AND CONTINGENCIES Leases The Company leases a facility containing 19,200 square feet of laboratory and office space, which is located at 840 Memorial Drive, Cambridge, Massachusetts. The lease expires in April 2024, subject to an option to extend the lease for an additional three years. The lease agreement and most recent amendment contained escalating rent payments. In December 2022, the Company initiated activities to vacate its corporate offices in Cambridge, Massachusetts, and the activities were completed in January 2023. As a result, the Company performed a recoverability test by comparing the future cash flows attributable to the asset group to the carrying value of the corresponding long-lived, right-of-use asset for its facility lease. Based on this evaluation, the Company determined that the long-lived asset with a carrying value of $2.1 million was no longer recoverable and recorded a right-of-use asset impairment of $2.1 million in December 2022. The impairment was determined by comparing the fair value of the impacted asset group to their carrying value as of the impairment measurement date, as required under ASC 360, Property, Plant, and Equipment. The Company continues to amortize the lease liability over the lease term while its lease agreement remains in place. The following table contains a summary of the lease costs recognized under ASC 842 and other information pertaining to the Company’s operating leases for the three and six months ended June 30, 2023 and 2022 (in thousands, except weighted average figures): Three Months Ended Six Months Ended Operating leases 2023 2022 2023 2022 Lease cost Operating lease cost $ 37 $ 401 $ 84 $ 803 Variable lease cost 173 160 369 353 Total lease cost $ 210 $ 561 $ 453 $ 1,156 Other information Operating cash flows used for operating leases $ — $ 578 $ 192 $ 1,181 Weighted average remaining lease term (years) 0.8 1.8 0.8 1.8 Weighted average discount rate (percentage) 9.0 % 9.0 % 9.0 % 9.0 % For the three and six months ended June 30, 2023, the Company recorded $0.2 million and $0.5 million in operating lease expense, respectively, and made lease payments of $0.0 million and $0.2 million, respectively, with such amounts reflected in the condensed consolidated statements of cash flows in operating activities. Future minimum lease payments and lease liabilities as of June 30, 2023 and December 31, 2022 were as follows (in thousands): As of Maturity of lease liabilities June 30, December 31, 2023 $ 870 $ 1,722 2024 580 580 Total future minimum lease payments $ 1,450 $ 2,302 Less: imputed interest (59) (141) Total lease liability $ 1,391 $ 2,161 Reported as: Current portion of operating lease liability $ 1,391 $ 1,592 Operating lease liability — 569 Total lease liability $ 1,391 $ 2,161 Other Commitments From time to time, the Company enters 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 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 non-cancelable obligations of service providers, up to the date of cancellation. Legal Proceedings From time to time, the Company may be involved in various claims, threatened or actual, and legal proceedings relating to claims arising out of our operations or products, if any.

RELATED-PARTY TRANSACTIONS

RELATED-PARTY TRANSACTIONS	6 Months Ended
	Jun. 30, 2023
Related Party Transactions [Abstract]
RELATED-PARTY TRANSACTIONS	RELATED-PARTY TRANSACTIONSThere were no material related-party transactions in the periods reported.

SUBSEQUENT EVENTS

SUBSEQUENT EVENTS	6 Months Ended
	Jun. 30, 2023
Subsequent Events [Abstract]
SUBSEQUENT EVENTS	SUBSEQUENT EVENTSThe Company has evaluated subsequent events for financial statement purposes occurring through the date these condensed consolidated financial statements were issued.

SUMMARY OF SIGNIFICANT ACCOUN_2

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)	6 Months Ended
	Jun. 30, 2023
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying condensed consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (“GAAP”). Any reference in these notes to applicable guidance is meant to refer to the authoritative United States generally accepted accounting principles as found in the Accounting Standards Codification (“ASC”) and Accounting Standards Update (“ASU”) of the Financial Accounting Standards Board (“FASB”). Furthermore, the accompanying condensed consolidated financial statements are unaudited and certain information and footnote disclosures normally included in financial statements prepared in accordance with GAAP have been condensed or omitted from this report, as is permitted by such rules and regulations. The unaudited interim financial statements have been prepared on the same basis as the audited annual financial statements as of and for the year ended December 31, 2022. The accompanying interim condensed consolidated financial statements reflect all adjustments, consisting of normal recurring adjustments, necessary for the fair presentation of the Company’s financial position as of June 30, 2023, the results of its operations for the three and six months ended June 30, 2023 and 2022, its cash flows for the six months ended June 30, 2023 and 2022, and its statements of stockholders’ equity (deficit) for the three and six months ended June 30, 2023 and 2022.
Principles of Consolidation	Principles of Consolidation The accompanying condensed consolidated financial statements include the accounts of the Company and its wholly owned subsidiary. All intercompany accounts and transactions have been eliminated in consolidation.
Use of Estimates	Use of Estimates The preparation of the condensed consolidated financial statements in accordance with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, equity, expenses and disclosure of contingent assets and liabilities at the date of the condensed consolidated financial statements and the Company’s ability to continue as a going concern. The Company bases its estimates on historical experience, known trends and other market-specific or relevant factors that it believes to be reasonable under the circumstances. On an ongoing basis, management evaluates its estimates as there are changes in circumstances, facts and experience. Actual results may differ from those estimates or assumptions.
Cash and Cash Equivalents	Cash and Cash Equivalents Cash and cash equivalents include cash held in banks and amounts held in interest-bearing money market accounts. Cash equivalents are carried at cost, which approximates their fair market value. The Company considers all highly liquid investments with a remaining maturity when purchased of three months or less to be cash equivalents.
Concentrations of Credit Risk	Concentrations of Credit Risk The Company has no off-balance sheet risk, such as foreign exchange contracts, option contracts, or other foreign hedging arrangements. Financial instruments that potentially expose the Company to concentrations of credit risk consist primarily of cash equivalents. The Company’s cash equivalents as of June 30, 2023 consisted of bank deposits and money market funds that invest in U.S. treasury securities. The Company's investment policy includes guidelines on the quality of the institutions and financial instruments and defines the allowable investments that the Company believes minimizes the exposure to concentrations of credit risk. The Company has not experienced any credit losses and does not believe that it is subject to significant credit risk.
Fair Value Measurements	Fair Value Measurements Certain assets and liabilities of the Company are carried at fair value. 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 — Quoted prices in active markets for identical assets or liabilities. • Level 2 — Observable inputs (other than Level 1 quoted prices), such as quoted prices in active markets for similar assets or liabilities, quoted prices in markets that are not active for identical or similar assets or liabilities, or other inputs that are observable or can be corroborated by observable market data. • Level 3 — Unobservable inputs that are supported by little or no market activity that are significant to determining the fair value of the assets or liabilities, including pricing models, discounted cash flow methodologies and similar techniques.
Property and Equipment - Long-Lived Assets Impairment	Property and Equipment Property and equipment are recorded at cost. Depreciation and amortization is calculated using the straight-line method over the estimated useful lives of the assets. Upon disposal, retirement or sale, the cost of assets disposed of and the related accumulated depreciation are removed from the accounts and any resulting gain or loss is included in the results of operations. Expenditures for repairs and maintenance that do not improve or extend the lives of the respective assets are charged to expense as incurred. Long-Lived Assets Impairment 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 and eventual disposition 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.
Leases	Leases The Company determines whether a contract is, or contains, a lease at inception and classifies leases as operating or financing considering factors such as the length of the lease term, the present value of the lease payments, the nature of the asset being leased, and the potential for ownership of the asset to transfer during the lease term. Leases with terms greater than one-year are recognized on the consolidated balance sheets as right-of-use assets and lease liabilities and are measured at the present value of the fixed payments due over the expected lease term less the present value of any incentives, rebates or abatements received from the lessor. Options to extend a lease are included in the expected lease term if exercise of the option is deemed reasonably certain. Costs determined to be variable and not based on an index or rate are not included in the measurement of the lease liability and are expensed as incurred. The interest rate implicit in lease contracts is typically not readily determinable. As such, the Company utilizes the appropriate incremental borrowing rate, which is the rate incurred to borrow on a collateralized basis an amount equal to the lease payments in the same currency, for a similar term, and in a similar economic environment. The Company records expense to recognize fixed lease payments on a straight-line basis over the expected lease term. The Company has elected the practical expedient not to separate lease and non-lease components for real estate leases.
Segment Information	Segment InformationOperating segments are identified as components of an enterprise about which separate discrete financial information is available for evaluation by the Chief Executive Officer, who is the chief operating decision maker, in making decisions on how to allocate resources and assess performance. The Company operates in one reportable business segment.
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. For the three and six months ended June 30, 2022, the Company’s only element of other comprehensive loss was unrealized gains (losses) on marketable securities. For the three and six months ended June 30, 2023, there were no elements of other comprehensive loss.
Net Loss Per Share	Net Loss Per ShareBasic net loss per share attributable to common stockholders is calculated by dividing net loss by the weighted average shares outstanding during the period. Diluted net income (loss) per share is calculated by adjusting weighted average shares outstanding for the dilutive effect of common stock equivalents outstanding for the period. All common stock equivalents have been excluded from the calculation of diluted net loss per share, as their effect would be anti-dilutive for all periods presented.
Newly Adopted Accounting Pronouncements	Newly Adopted Accounting Pronouncements In June 2016, the FASB issued ASU 2016-13, Financial Instruments – Credit Losses (Topic 326) . The new standard adjusts the accounting for assets held at amortized cost basis, including marketable securities accounted for as available-for-sale. The standard eliminates the probable initial recognition threshold and requires an entity to reflect its current estimate of all expected credit losses. The allowance for credit losses is a valuation account that is deducted from the amortized cost basis of the financial assets to present the net amount expected to be collected. The adoption of this standard on January 1, 2023 did not have a material impact on its condensed consolidated financial statements.

FAIR VALUE MEASUREMENTS (Tables

FAIR VALUE MEASUREMENTS (Tables)	6 Months Ended
	Jun. 30, 2023
Fair Value Disclosures [Abstract]
Schedule of Assets Measured at Fair Value	The following tables present the Company’s assets that are measured at fair value on a recurring basis and indicate the level within the fair value hierarchy (in thousands): Fair Value Measurements at June 30, 2023 using: Level 1 Level 2 Level 3 Total Assets: Cash equivalents: Money market funds $ 8,726 $ — $ — $ 8,726 Total $ 8,726 $ — $ — $ 8,726 Fair Value Measurements at December 31, 2022 using: Level 1 Level 2 Level 3 Total Assets: Cash equivalents: Money market funds $ 14,649 $ — $ — $ 14,649 Total $ 14,649 $ — $ — $ 14,649

PROPERTY AND EQUIPMENT (Tables)

PROPERTY AND EQUIPMENT (Tables)	6 Months Ended
	Jun. 30, 2023
Property, Plant and Equipment [Abstract]
Summary of Property and Equipment	Property and equipment consist of the following (in thousands): June 30, December 31, Laboratory equipment $ — $ 3,506 Leasehold improvements — 564 Office and computer equipment 87 303 Furniture and fixtures — 122 Property and equipment 87 4,495 Less: accumulated depreciation and amortization (72) (3,802) Property and equipment, net $ 15 $ 693

ACCRUED EXPENSES AND OTHER CU_2

ACCRUED EXPENSES AND OTHER CURRENT LIABILITIES (Tables)	6 Months Ended
	Jun. 30, 2023
Payables and Accruals [Abstract]
Schedule of Accrued Expenses and Other Current Liabilities	Accrued expenses and other current liabilities consisted of the following (in thousands): June 30, December 31, Accrued employee compensation and benefits $ 470 $ 808 Accrued external research and development expenses 843 4,791 Accrued professional fees 441 824 Accrued employee termination benefits — 1,221 Other — 205 Total accrued expenses and other current liabilities $ 1,754 $ 7,849

STOCKHOLDERS' EQUITY (DEFICIT)

STOCKHOLDERS' EQUITY (DEFICIT) (Tables)	6 Months Ended
	Jun. 30, 2023
Equity [Abstract]
Schedule of Stock-based Compensation Expense Recognized	In connection with all share-based payment awards, total stock-based compensation expense recognized was as follows (in thousands): Three Months Ended Six Months Ended 2023 2022 2023 2022 Research and development $ 97 $ 275 $ 266 $ 841 General and administrative 331 319 701 1,262 Total stock-based compensation expense $ 428 $ 594 $ 967 $ 2,103
Schedule of Fair Value Assumptions for Stock Options	The Black-Scholes option pricing model assumptions are included in the table below. No options were granted during the three months ended June 30, 2023. Three Months Ended Six Months Ended 2023 2022 2023 2022 Risk-free interest rate — 2.89 % 3.95 % 2.01 % Expected option life (in years) — 5.75 6.11 6.08 Expected dividend yield — — % — % — % Expected volatility — 95.3 % 90.1 % 91.9 %
Schedule of Stock Option Activity	The following table summarizes the Company’s stock option activity for the six months ended June 30, 2023: Number of Shares Weighted Weighted Intrinsic Outstanding as of January 1, 2023 6,536,977 $ 5.05 Granted 611,500 0.68 Exercised — — Canceled (1,746,381) 4.22 Outstanding as of June 30, 2023 5,402,096 $ 4.82 6.44 $ — Exercisable as of June 30, 2023 3,995,701 $ 5.66 5.61 $ — Vested or expected to vest as of June 30, 2023 5,402,096 $ 4.82 6.44 $ —
Schedule of Restricted Stock Unit Activity	The following table summarizes the Company's restricted stock unit activity for the six months ended June 30, 2023: Number of Shares Weighted Average Outstanding as of January 1, 2023 75,233 $ 5.04 Granted — — Vested (37,525) 3.88 Forfeited (9,375) 5.00 Outstanding as of June 30, 2023 28,333 $ 6.59

NET LOSS PER SHARE (Tables)

NET LOSS PER SHARE (Tables)	6 Months Ended
	Jun. 30, 2023
Earnings Per Share [Abstract]
Schedule of Earnings Per Share, Basic and Diluted	Basic and diluted net loss per share attributable to common stockholders was calculated as follows (in thousands, except share and per share amounts): Three Months Ended Six Months Ended 2023 2022 2023 2022 Numerator: Net loss $ (3,413) $ (21,306) $ (7,389) $ (40,345) Denominator: Weighted average common shares outstanding, basic and diluted 73,688,558 52,616,279 73,678,881 47,052,105 Net loss per share, basic and diluted $ (0.05) $ (0.40) $ (0.10) $ (0.86)
Schedule of Antidilutive Securities Excluded from Computation of Earnings 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: Six Months Ended 2023 2022 Options to purchase common stock 5,402,096 7,790,334 Unvested restricted stock units 28,333 182,593 Shares issuable under employee stock purchase plan — 65,790 5,430,429 8,038,717

COMMITMENTS AND CONTINGENCIES (

COMMITMENTS AND CONTINGENCIES (Tables)	6 Months Ended
	Jun. 30, 2023
Commitments and Contingencies Disclosure [Abstract]
Schedule of Lease Costs	The following table contains a summary of the lease costs recognized under ASC 842 and other information pertaining to the Company’s operating leases for the three and six months ended June 30, 2023 and 2022 (in thousands, except weighted average figures): Three Months Ended Six Months Ended Operating leases 2023 2022 2023 2022 Lease cost Operating lease cost $ 37 $ 401 $ 84 $ 803 Variable lease cost 173 160 369 353 Total lease cost $ 210 $ 561 $ 453 $ 1,156 Other information Operating cash flows used for operating leases $ — $ 578 $ 192 $ 1,181 Weighted average remaining lease term (years) 0.8 1.8 0.8 1.8 Weighted average discount rate (percentage) 9.0 % 9.0 % 9.0 % 9.0 %
Schedule of Future Minimum Lease Payments	Future minimum lease payments and lease liabilities as of June 30, 2023 and December 31, 2022 were as follows (in thousands): As of Maturity of lease liabilities June 30, December 31, 2023 $ 870 $ 1,722 2024 580 580 Total future minimum lease payments $ 1,450 $ 2,302 Less: imputed interest (59) (141) Total lease liability $ 1,391 $ 2,161 Reported as: Current portion of operating lease liability $ 1,391 $ 1,592 Operating lease liability — 569 Total lease liability $ 1,391 $ 2,161

NATURE OF BUSINESS (Details)

NATURE OF BUSINESS (Details) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2023	Mar. 31, 2023	Jun. 30, 2022	Mar. 31, 2022	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Accumulated deficit	$ (425,816)				$ (425,816)		$ (418,427)
Cash and cash equivalents	8,884				8,884		$ 17,147
Net loss	(3,413)	$ (3,976)	$ (21,306)	$ (19,039)	(7,389)	$ (40,345)
Net cash used in operations	$ (8,800)				$ (8,761)	$ (35,529)

SUMMARY OF SIGNIFICANT ACCOUN_3

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details)	6 Months Ended
	Jun. 30, 2023 segment
Accounting Policies [Abstract]
Number of operating segments	1

FAIR VALUE MEASUREMENTS (Detail

FAIR VALUE MEASUREMENTS (Details) - Fair Value, Recurring - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Assets, Fair Value Disclosure [Abstract]
Money market funds	$ 8,726	$ 14,649
Total	8,726	14,649
Level 1
Assets, Fair Value Disclosure [Abstract]
Money market funds	8,726	14,649
Total	8,726	14,649
Level 2
Assets, Fair Value Disclosure [Abstract]
Money market funds	0	0
Total	0	0
Level 3
Assets, Fair Value Disclosure [Abstract]
Money market funds	0	0
Total	$ 0	$ 0

PROPERTY AND EQUIPMENT - Summar

PROPERTY AND EQUIPMENT - Summary of Property and Equipment (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Property, Plant and Equipment [Line Items]
Property and equipment	$ 87	$ 4,495
Less: accumulated depreciation and amortization	(72)	(3,802)
Property and equipment, net	15	693
Laboratory equipment
Property, Plant and Equipment [Line Items]
Property and equipment	0	3,506
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property and equipment	0	564
Office and computer equipment
Property, Plant and Equipment [Line Items]
Property and equipment	87	303
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Property and equipment	$ 0	$ 122

PROPERTY AND EQUIPMENT - Narrat

PROPERTY AND EQUIPMENT - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Property, Plant and Equipment [Abstract]
Depreciation and amortization	$ 0	$ 100	$ 21	$ 159
Property and equipment disposed of			500
Gain on the sale of property and equipment			$ 68	$ 0

ACCRUED EXPENSES AND OTHER CU_3

ACCRUED EXPENSES AND OTHER CURRENT LIABILITIES (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2023	Dec. 31, 2022
Payables and Accruals [Abstract]
Accrued employee compensation and benefits	$ 470	$ 808
Accrued external research and development expenses	843	4,791
Accrued professional fees	441	824
Accrued employee termination benefits	0	1,221
Other	0	205
Total accrued expenses and other current liabilities	1,754	$ 7,849
Payments for employee termination	$ 1,200

STOCKHOLDERS' EQUITY (DEFICIT_2

STOCKHOLDERS' EQUITY (DEFICIT) - Narrative (Details) - USD ($) $ / shares in Units, $ in Millions		6 Months Ended
	Apr. 29, 2019	Jun. 30, 2023	Jun. 30, 2022
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares initially reserved for future issuance (in shares)	237,181
Annual percent increase in authorized shares available for issuance under share based payment arrangements	1%
Exercise of common stock options (in shares)		0
Weighted-average grand date fair value of options granted in the period (USD per share)		$ 0.52	$ 1.09
Unrecognized compensation expense related to unvested stock options		$ 2.2
ESPP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for future issuance (in shares)		935,186
Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense, recognition period		1 year 10 months 24 days
RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense, recognition period		7 months 6 days
Unrecognized compensation expense related to unvested stock RSUs		$ 0.1
Stock Option And Incentive Plan 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum award term		10 years
Number of shares initially reserved for future issuance (in shares)	905,000
Annual percent increase in authorized shares available for issuance under share based payment arrangements	4%
Common stock reserved for future issuance (in shares)		6,407,936
Stock Option And Incentive Plan 2019 | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period		4 years
Stock Option And Incentive Plan 2019 | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period		3 years

STOCKHOLDERS' EQUITY (DEFICIT_3

STOCKHOLDERS' EQUITY (DEFICIT) - Summary of Stock Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total stock-based compensation expense	$ 428	$ 594	$ 967	$ 2,103
Research and development
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total stock-based compensation expense	97	275	266	841
General and administrative
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total stock-based compensation expense	$ 331	$ 319	$ 701	$ 1,262

STOCKHOLDERS' EQUITY (DEFICIT_4

STOCKHOLDERS' EQUITY (DEFICIT) - Stock Option Valuation Fair Value Measurement Inputs (Details) - Stock options	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rate	0%	2.89%	3.95%	2.01%
Expected option life (in years)	0 years	5 years 9 months	6 years 1 month 9 days	6 years 29 days
Expected dividend yield	0%	0%	0%	0%
Expected volatility	0%	95.30%	90.10%	91.90%

STOCKHOLDERS' EQUITY (DEFICIT_5

STOCKHOLDERS' EQUITY (DEFICIT) - Summary of Stock Option Activity (Details) $ / shares in Units, $ in Thousands	6 Months Ended
	Jun. 30, 2023 USD ($) $ / shares shares
Number of Shares
Outstanding at beginning of period (in shares) | shares	6,536,977
Granted (in shares) | shares	611,500
Exercised (in shares) | shares	0
Canceled (in shares) | shares	(1,746,381)
Outstanding at end of period (in shares) | shares	5,402,096
Shares exercisable (in shares) | shares	3,995,701
Shares vested or expected to vest (in shares) | shares	5,402,096
Weighted Average Exercise Price
Weighted average exercise price of shares outstanding at beginning of period (USD per share) | $ / shares	$ 5.05
Weighted-average exercise price of shares granted (USD per share) | $ / shares	0.68
Weighted-average exercise price of shares exercised (USD per share) | $ / shares	0
Weighted-average exercise price of shares canceled (USD per share) | $ / shares	4.22
Weighted average exercise price of shares outstanding at end of period (USD per share) | $ / shares	4.82
Weighted-average exercise price of shares exercisable (USD per share) | $ / shares	5.66
Weighted-average exercise price of shares vested or expected to vest (USD per share) | $ / shares	$ 4.82
Weighted Average Remaining Life (in Years)
Weighted average remaining life of shares outstanding (in years)	6 years 5 months 8 days
Weighted average remaining life of shares exercisable (in years)	5 years 7 months 9 days
Weighted average remaining life of shares vested or expected to vest (in years)	6 years 5 months 8 days
Intrinsic value of shares outstanding | $	$ 0
Intrinsic value of shares exercisable | $	0
Intrinsic value of shares vested or expected to vest | $	$ 0

STOCKHOLDERS' EQUITY (DEFICIT_6

STOCKHOLDERS' EQUITY (DEFICIT) - Summary of Restricted Stock Units (Details) - RSUs	6 Months Ended
	Jun. 30, 2023 $ / shares shares
Number of Shares
Outstanding at beginning of period (in shares) | shares	75,233
Granted (in shares) | shares	0
Vested (in shares) | shares	(37,525)
Forfeited (in shares) | shares	(9,375)
Outstanding at end of period (in shares) | shares	28,333
Weighted Average Grant Date Fair Value per Share
Weighted average exercise price of RSUs outstanding at beginning of period (USD per share) | $ / shares	$ 5.04
Weighted-average exercise price of RSUs granted (USD per share) | $ / shares	0
Weighted-average exercise price of RSUs vested (USD per share) | $ / shares	3.88
Weighted-average exercise price of RSUs forfeited (USD per share) | $ / shares	5
Weighted average exercise price of RSUs outstanding at end of period (USD per share) | $ / shares	$ 6.59

NET LOSS PER SHARE - Schedule o

NET LOSS PER SHARE - Schedule of Earnings Per Share, Basic and Diluted (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2023	Mar. 31, 2023	Jun. 30, 2022	Mar. 31, 2022	Jun. 30, 2023	Jun. 30, 2022
Numerator:
Net loss	$ (3,413)	$ (3,976)	$ (21,306)	$ (19,039)	$ (7,389)	$ (40,345)
Denominator:
Weighted average common shares outstanding, basic (in shares)	73,688,558		52,616,279		73,678,881	47,052,105
Weighted average common shares outstanding, diluted (in shares)	73,688,558		52,616,279		73,678,881	47,052,105
Net loss per share, basic (USD per share)	$ (0.05)		$ (0.40)		$ (0.10)	$ (0.86)
Net loss per share, diluted (USD per share)	$ (0.05)		$ (0.40)		$ (0.10)	$ (0.86)

NET LOSS PER SHARE - Schedule_2

NET LOSS PER SHARE - Schedule of Anti-dilutive Securities (Details) - shares	6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of diluted net loss per share (in shares)	5,430,429	8,038,717
Options to purchase common stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of diluted net loss per share (in shares)	5,402,096	7,790,334
Unvested restricted stock units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of diluted net loss per share (in shares)	28,333	182,593
Shares issuable under employee stock purchase plan
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of diluted net loss per share (in shares)	0	65,790

COMMITMENTS AND CONTINGENCIES -

COMMITMENTS AND CONTINGENCIES - Narrative (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023 USD ($) ft²	Jun. 30, 2022 USD ($)	Jun. 30, 2023 USD ($) ft²	Jun. 30, 2022 USD ($)	Dec. 31, 2022 USD ($)
Other Commitments [Line Items]
Leased facility area (in square feet) | ft²	19,200		19,200
Lease extension term	3 years		3 years
Operating Lease, Impairment Loss			$ 2,100
Lease cost	$ 210	$ 561	453	$ 1,156
Operating cash flows used for operating leases	0	$ 578	192	$ 1,181
Abbey Group Dispute
Other Commitments [Line Items]
Claim for damages	$ 1,000		$ 1,000
Cumulative Effect, Period of Adoption, Adjustment | Accounting Standards Update 2016-02
Other Commitments [Line Items]
Operating lease right-of-use asset					$ 2,100

COMMITMENTS AND CONTINGENCIES_2

COMMITMENTS AND CONTINGENCIES - Schedule of Lease Costs (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Commitments and Contingencies Disclosure [Abstract]
Operating lease cost	$ 37	$ 401	$ 84	$ 803
Variable lease cost	173	160	369	353
Total lease cost	210	561	453	1,156
Operating cash flows used for operating leases	$ 0	$ 578	$ 192	$ 1,181
Weighted average remaining lease term (years)	9 months 18 days	1 year 9 months 18 days	9 months 18 days	1 year 9 months 18 days
Weighted average discount rate (percentage)	9%	9%	9%	9%

COMMITMENTS AND CONTINGENCIES_3

COMMITMENTS AND CONTINGENCIES - Schedule of Future Minimum Lease Payments (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Lessee, Operating Lease, Liability, Payment, Due [Abstract]
2023	$ 870
2024	580	$ 1,722
2024		580
Total future minimum lease payments	1,450	2,302
Less: imputed interest	(59)	(141)
Total lease liability	1,391	2,161
Current portion of operating lease liability	1,391	1,592
Operating lease liability	$ 0	$ 569