Acumen Pharmaceuticals (ABOS) 10-Q12 Nov 242024 Q3 Quarterly reportFinancial data

Company Profile

Cover

Cover - shares	9 Months Ended
Cover - shares	Sep. 30, 2024	Nov. 07, 2024
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2024
Document Transition Report	false
Entity File Number	001-40551
Entity Registrant Name	Acumen Pharmaceuticals, Inc.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	36-4108129
Entity Address, Address Line One	1210-1220 Washington Street
Entity Address, Address Line Two	Suite 210
Entity Address, City or Town	Newton
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	02465
City Area Code	617
Local Phone Number	344-4190
Title of 12(b) Security	Common stock, par value $0.0001 per share
Trading Symbol	ABOS
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		60,079,778
Current Fiscal Year End Date	--12-31
Amendment Flag	false
Entity Central Index Key	0001576885
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	Q3

Condensed Balance Sheets

Condensed Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Current assets
Cash and cash equivalents	$ 33,184	$ 66,886
Marketable securities, short-term	167,159	176,636
Prepaid expenses and other current assets	7,289	3,093
Total current assets	207,632	246,615
Marketable securities, long-term	58,552	62,553
Right-of-use asset	296	381
Restricted cash	236	233
Property and equipment, net	89	122
Other assets	170	221
Total assets	266,975	310,125
Current liabilities
Accounts payable	2,342	1,379
Accrued clinical trial expenses	12,517	4,387
Accrued expenses and other current liabilities	4,926	6,339
Finance lease liability, short-term	0	756
Operating lease liability, short-term	129	110
Total current liabilities	19,914	12,971
Operating lease liability, long-term	185	284
Debt, long-term	29,674	29,897
Total liabilities	49,773	43,152
Commitments and contingencies (Note 10)
Stockholders’ equity
Preferred stock, $0.0001 par value; 10,000,000 shares authorized and no shares issued and outstanding as of September 30, 2024 and December 31, 2023	0	0
Common stock, $0.0001 par value; 300,000,000 shares authorized as of September 30, 2024 and December 31, 2023; 60,079,778 and 57,910,461 shares issued and outstanding as of September 30, 2024 and December 31, 2023, respectively	6	6
Additional paid-in capital	504,651	489,453
Accumulated deficit	(287,973)	(222,798)
Accumulated other comprehensive income	518	312
Total stockholders’ equity	217,202	266,973
Total liabilities and stockholders’ equity	$ 266,975	$ 310,125

Condensed Balance Sheets (Paren

Condensed Balance Sheets (Parenthetical) - $ / shares	Sep. 30, 2024	Dec. 31, 2023
Statement of Financial Position [Abstract]
Preferred stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Preferred stock, shares authorized (in shares)	10,000,000	10,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Common stock, shares authorized (in shares)	300,000,000	300,000,000
Common stock, shares issued (in shares)	60,079,778	57,910,461
Common stock, shares outstanding (in shares)	60,079,778	57,910,461

Condensed Statements of Operati

Condensed Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Operating expenses
Research and development	$ 27,247	$ 11,179	$ 59,229	$ 29,025
General and administrative	5,018	4,860	15,191	13,627
Total operating expenses	32,265	16,039	74,420	42,652
Loss from operations	(32,265)	(16,039)	(74,420)	(42,652)
Other income (expense)
Interest income	3,504	3,124	11,325	6,840
Interest expense	(1,027)	0	(3,031)	0
Change in fair value of embedded derivatives	(10)	0	1,040	0
Other income (expense), net	33	(42)	(89)	(62)
Total other income	2,500	3,082	9,245	6,778
Net loss	(29,765)	(12,957)	(65,175)	(35,874)
Other comprehensive gain (loss)
Unrealized gain on marketable securities	682	137	206	242
Comprehensive loss	$ (29,083)	$ (12,820)	$ (64,969)	$ (35,632)
Net loss per common share, basic (in dollars per share)	$ (0.50)	$ (0.24)	$ (1.09)	$ (0.79)
Net loss per common share, diluted (in dollars per share)	$ (0.50)	$ (0.24)	$ (1.09)	$ (0.79)
Weighted-average shares outstanding, basic (in shares)	60,079,778	54,229,630	59,990,844	45,474,953
Weighted-average shares outstanding diluted (in shares)	60,079,778	54,229,630	59,990,844	45,474,953

Condensed Statements of Changes

Condensed Statements of Changes in Stockholders’ Equity - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Deficit	Accumulated Other Comprehensive Income
Beginning balance (in shares) at Dec. 31, 2022		41,025,062
Beginning balance at Dec. 31, 2022	$ 188,775	$ 4	$ 359,949	$ (170,427)	$ (751)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock for cash, net of issuance costs (in shares)		16,774,193
Issuance of common stock for cash, net of issuance costs	122,294	$ 2	122,292
Stock options exercised for cash (in shares)		111,206
Stock options exercised for cash	325		325
Unrealized gain on marketable securities	242				242
Stock-based compensation	4,511		4,511
Net loss	(35,874)			(35,874)
Ending balance (in shares) at Sep. 30, 2023		57,910,461
Ending balance at Sep. 30, 2023	280,273	$ 6	487,077	(206,301)	(509)
Beginning balance (in shares) at Jun. 30, 2023		41,025,062
Beginning balance at Jun. 30, 2023	168,874	$ 4	362,860	(193,344)	(646)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock for cash, net of issuance costs (in shares)		16,774,193
Issuance of common stock for cash, net of issuance costs	122,294	$ 2	122,292
Stock options exercised for cash (in shares)		111,206
Stock options exercised for cash	325		325
Unrealized gain on marketable securities	137				137
Stock-based compensation	1,600		1,600
Net loss	(12,957)			(12,957)
Ending balance (in shares) at Sep. 30, 2023		57,910,461
Ending balance at Sep. 30, 2023	$ 280,273	$ 6	487,077	(206,301)	(509)
Beginning balance (in shares) at Dec. 31, 2023	57,910,461	57,910,461
Beginning balance at Dec. 31, 2023	$ 266,973	$ 6	489,453	(222,798)	312
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock for cash, net of issuance costs (in shares)		2,068,246
Issuance of common stock for cash, net of issuance costs	7,938		7,938
Issuance of common stock for restricted stock units, net of shares withheld for taxes (in shares)		101,071
Issuance of common stock for restricted stock units, net of shares withheld for taxes	(32)		(32)
Unrealized gain on marketable securities	206				206
Stock-based compensation	7,292		7,292
Net loss	$ (65,175)			(65,175)
Ending balance (in shares) at Sep. 30, 2024	60,079,778	60,079,778
Ending balance at Sep. 30, 2024	$ 217,202	$ 6	504,651	(287,973)	518
Beginning balance (in shares) at Jun. 30, 2024		60,079,778
Beginning balance at Jun. 30, 2024	243,947	$ 6	502,313	(258,208)	(164)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Unrealized gain on marketable securities	682				682
Stock-based compensation	2,338		2,338
Net loss	$ (29,765)			(29,765)
Ending balance (in shares) at Sep. 30, 2024	60,079,778	60,079,778
Ending balance at Sep. 30, 2024	$ 217,202	$ 6	$ 504,651	$ (287,973)	$ 518

Condensed Statements of Chang_2

Condensed Statements of Changes in Stockholders’ Equity (Parenthetical) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Common Stock
Issuance of common stock for cash, net of issuance costs	$ 7,706	$ 87	$ 7,706

Condensed Statements of Cash Fl

Condensed Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
Condensed Statements of Cash Flows - USD ($) $ in Thousands	Sep. 30, 2024	Sep. 30, 2023
Cash flows from operating activities
Net loss	$ (65,175)	$ (35,874)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation	49	42
Stock-based compensation expense	7,292	4,511
Amortization of premiums and accretion of discounts on marketable securities, net	(4,599)	(1,344)
Change in fair value of embedded derivatives	(1,040)	0
Amortization of right-of-use asset	85	103
Realized gains on marketable securities	(97)	0
Non-cash interest expense	823	0
Other non-cash expense	230	0
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	(4,196)	(436)
Other assets	51	(38)
Accounts payable	963	(278)
Accrued clinical trial expenses	8,130	(1,151)
Accrued expenses and other current liabilities	(1,413)	(182)
Finance lease liability	(23)	0
Operating lease liability	(80)	(103)
Net cash used in operating activities	(59,000)	(34,750)
Cash flows from investing activities
Purchases of marketable securities	(155,631)	(178,857)
Proceeds from maturities and sales of marketable securities	174,011	55,997
Proceeds from sale of property and equipment	0	3
Purchases of property and equipment	(16)	(7)
Net cash provided by (used in) investing activities	18,364	(122,864)
Cash flows from financing activities
Proceeds from issuance of common stock, net of issuance costs	7,938	122,294
Payment for financing lease	(739)	0
Payments for deferred offering costs	(230)	0
Repurchase of common shares to pay employee withholding taxes	(32)	0
Proceeds from exercise of stock options	0	325
Net cash provided by financing activities	6,937	122,619
Net change in cash and cash equivalents and restricted cash	(33,699)	(34,995)
Cash and cash equivalents and restricted cash at the beginning of the period	67,119	130,101
Cash and cash equivalents and restricted cash at the end of the period	33,420	95,106
Supplemental disclosure of cash flow information
Cash paid for income taxes	0	0
Cash paid for interest	2,235	0
Supplemental disclosure of noncash investing and financing activities
Proceeds from sale of property and equipment in other current assets	$ 0	$ 4

DESCRIPTION OF ORGANIZATION AND

DESCRIPTION OF ORGANIZATION AND BUSINESS OPERATIONS	9 Months Ended
DESCRIPTION OF ORGANIZATION AND BUSINESS OPERATIONS	Sep. 30, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
DESCRIPTION OF ORGANIZATION AND BUSINESS OPERATIONS	DESCRIPTION OF ORGANIZATION AND BUSINESS OPERATIONS Acumen Pharmaceuticals, Inc. (“Acumen” or the “Company”) was incorporated in 1996 in the state of Delaware. Acumen is a clinical-stage biopharmaceutical company developing a novel disease-modifying approach to target what the Company believes to be a key underlying cause of Alzheimer’s disease (“AD”). Alzheimer’s disease is a progressive neurodegenerative disease of the brain that leads to loss of memory and cognitive functions and ultimately results in death. The Company’s scientific founders pioneered research on soluble amyloid-beta oligomers (“AßOs”), which are globular assemblies of the amyloid-beta (“Aß”) peptide that are distinct from Aß monomers and amyloid plaques. Based on decades of research and supporting evidence, AßOs have gained increasing scientific acceptance as a primary toxin involved in the initiation and propagation of AD pathology. The Company is currently focused on advancing a targeted immunotherapy drug candidate, sabirnetug, in its Phase 2 ALTITUDE-AD clinical trial following the results of INTERCEPT-AD, its Phase 1 clinical trial of sabirnetug in “early AD” patients (patients with mild cognitive impairment or mild dementia due to Alzheimer’s disease), which were first reported in July 2023. Sabirnetug is a recombinant humanized immunoglobulin gamma 2 (“IgG2”) monoclonal antibody (“mAb”) that was designed to selectively target AßOs, has demonstrated functional and protective effects in in vitro assays, and has previously demonstrated in vivo safety and pharmacologic activity in multiple animal species, including transgenic mouse models for AD. The Company has amended the ALTITUDE-AD clinical trial protocol from a Phase 2/3 study to a Phase 2 standalone study. The Company is subject to the uncertainty of whether its intellectual property will develop into successful commercial products. Liquidity and Capital Resources The Company has incurred operating losses since inception and expects to continue to incur significant operating losses for the foreseeable future and may never become profitable. As of September 30, 2024 and December 31, 2023, the Company had an accumulated deficit of $288.0 million and $222.8 million, respectively, and working capital of $187.7 million and $233.6 million, respectively. Management believes that the Company has sufficient cash to continue operating activities for beyond 12 months from issuance of these condensed financial statements. Future capital requirements will depend upon many factors, including the timing and extent of spending on research and development and market acceptance of the Company’s products, if approved for commercial sale. The Company expects that it will need to obtain additional financing to complete clinical trials and launch and commercialize any product candidates for which it receives regulatory approval. Until such time, if ever, as the Company can generate revenue sufficient to achieve profitability, the Company expects to finance its operations through a combination of equity offerings, debt financings, collaborations, strategic alliances and licensing arrangements. There can be no assurance that any such financing will be available on terms acceptable to the Company, or at all. To the extent that the Company raises additional capital through the sale of equity or convertible debt securities, the ownership interest of its stockholders will be diluted, and the terms of these securities may include liquidation or other preferences that adversely affect the rights of common stockholders. Debt financing and preferred equity financing, if available, may involve agreements that include covenants limiting or restricting the Company’s ability to take specific actions, such as incurring additional debt, making acquisitions or capital expenditures or declaring dividends. If the Company is unable to maintain sufficient financial resources, its business, financial condition and results of operations will be materially and adversely affected. The Company may be required to delay, limit, reduce or terminate its product discovery and development activities or future commercialization efforts. The Company completed its INTERCEPT-AD clinical trial in the second quarter of 2023. This trial enrolled 65 patients and 62 participants received at least one dose of study drug. INTERCEPT-AD was a U.S.-based, multi-center, randomized, double-blind, placebo-controlled clinical trial with overlapping single ascending dose and multiple ascending dose cohorts evaluating patients with early AD. In July 2023, the Company announced topline results from INTERCEPT-AD, which demonstrated that sabirnetug met the primary and secondary objectives of this study in 62 participants with early AD. The Company announced the dosing of the first patient in our Phase 2 ALTITUDE-AD clinical trial in May 2024, and expects to complete enrollment in the first half of 2025.

BASIS OF PRESENTATION AND SUMMA

BASIS OF PRESENTATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	9 Months Ended
	Sep. 30, 2024
Accounting Policies [Abstract]
BASIS OF PRESENTATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	BASIS OF PRESENTATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Basis of Presentation The accompanying unaudited condensed financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”) for interim financial information, the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the information and notes required by U.S. GAAP for complete financial statements. In the opinion of management, the unaudited condensed financial statements reflect all adjustments, which include only normal recurring adjustments, necessary to present fairly the Company’s financial position and results of its operations and its cash flows for the periods presented. Certain information and note disclosures normally included in the Company’s annual financial statements prepared in accordance with U.S. GAAP have been condensed or omitted. These unaudited condensed financial statement results are not necessarily indicative of results to be expected for the full fiscal year or any future period. A description of the Company’s significant accounting policies is included in the Company’s Annual Report. There have been no material changes in the Company’s significant accounting policies to those previously disclosed in the Company’s Annual Report. Use of Estimates The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the unaudited condensed financial statements, as well as the reported amounts of expenses during the reporting periods. These estimates and assumptions are based on the Company’s historical experience, and on various other factors that management believes are reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities and the recording of expenses that are not readily apparent from other sources. Actual results may differ from these estimates under different assumptions or conditions. To the extent there are material differences between the estimates and actual results, the Company’s future results of operations will be affected. The more significant estimates and assumptions by management include, among others: the valuation allowance of deferred tax assets resulting from net operating losses, the valuation of stock options and the valuation of embedded derivatives within the Company’s long-term debt. Cash and Cash Equivalents and Restricted Cash The Company considers all highly liquid investments with an original maturity of three months or less at the date of purchase to be cash equivalents. All of the Company’s cash equivalents have liquid markets and high credit ratings. The Company had $32.8 million and $66.2 million in cash equivalents as of September 30, 2024 and December 31, 2023, respectively. Restricted cash primarily consists of deposited cash collateral for the Company’s credit card program. The following table provides a reconciliation of cash, cash equivalents and restricted cash from the balance sheets to the statements of cash flows (in thousands): September 30, 2024 December 31, 2023 Cash and cash equivalents $ 33,184 $ 66,886 Restricted cash 236 233 Total cash, cash equivalents and restricted cash $ 33,420 $ 67,119 Recently Issued Accounting Pronouncements From time to time, new accounting pronouncements are issued by the Financial Accounting Standards Board (“FASB”) or other standard setting bodies that the Company adopts as of the specified effective date. Unless otherwise discussed below, the Company does not believe that the adoption of recently issued standards have or may have a material impact on its financial statements and disclosures. In November 2023, the FASB issued Accounting Standards Update (“ASU”) 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures. The standard is intended to improve financing reporting by requiring disclosure of incremental segment information on an annual and interim basis for all public entities to enable investors to develop more decision-useful financial analyses. The standard is effective for fiscal years beginning after December 31, 2023, and interim periods within fiscal years beginning after December 15, 2024. Upon adoption, the standard should be applied retrospectively to all prior periods presented in the financial statements. The Company is evaluating the potential impact of this adoption on its financial statements and related disclosures. In December 2023, the FASB issued ASU 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures. The standard is intended to enhance the existing income tax disclosures to provide information to better assess how an entity’s operations and related tax risks and tax planning and operational opportunities affect its tax rate and prospects for future cash flows. The standard is effective for annual periods beginning after December 15, 2024. Upon adoption, the standard should be applied on a prospective basis, although retrospective application is permitted. Early adoption is also permitted. The Company is evaluating the potential impact of this adoption on the financial statements and related disclosures. In November 2024, the FASB issued ASU 2024-03, Income Statement – Reporting Comprehensive Income – Expense Disaggregation Disclosures (Subtopic 220-40): Disaggregation of Income Statement Expenses. The standard is intended to require more detailed disclosures about specified categories of expenses, including employee compensation, depreciation and amortization, included in certain expense captions presented on the face of the income statement. The ASU is effective for fiscal years beginning after December 15, 2026, and for interim periods within fiscal years beginning after December 31, 2027. Early adoption is permitted. The amendments may be applied either (1) prospectively to financial statements issued for reporting periods after the effective date of this ASU or (2) retrospectively to all prior periods presented in the financial statements. The Company is evaluating the potential impact of this adoption on the financial statements and related disclosures.

MARKETABLE SECURITIES

MARKETABLE SECURITIES	9 Months Ended
MARKETABLE SECURITIES	Sep. 30, 2024
Marketable Securities [Abstract]
MARKETABLE SECURITIES	MARKETABLE SECURITIES The Company’s marketable securities consisted of the following (in thousands): September 30, 2024 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Available-for-sale securities, short-term Corporate debt securities $ 139,840 $ 300 $ (18) $ 140,122 Government and agency - U.S. 26,979 58 — 27,037 Total available-for-sale securities, short-term 166,819 358 (18) 167,159 Available-for-sale securities, long-term Corporate debt securities 58,374 179 (1) 58,552 Total available-for-sale securities, long-term 58,374 179 (1) 58,552 Total available-for-sale securities $ 225,193 $ 537 $ (19) $ 225,711 December 31, 2023 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Available-for-sale securities, short-term Corporate debt securities $ 144,184 $ 97 $ (191) $ 144,090 Government and agency - U.S. 32,470 82 (6) 32,546 Total available-for-sale securities, short-term 176,654 179 (197) 176,636 Available-for-sale securities, long-term Corporate debt securities 57,240 320 (15) 57,545 Government and agency - U.S. 4,985 23 — 5,008 Total available-for-sale securities, long-term 62,225 343 (15) 62,553 Total available-for-sale securities $ 238,879 $ 522 $ (212) $ 239,189 The following tables summarize the amount of unrealized losses, defined as the amount by which the amortized cost exceeds fair value, and the related fair value of available-for-sale marketable securities with unrealized losses, which have been segregated into two categories: those that have been in a continuous unrealized loss position for less than 12 months and those that have been in a continuous unrealized loss position for 12 or more months (in thousands): September 30, 2024 Less than 12 Months Greater than 12 Months Total Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses Corporate debt securities $ 13,351 $ (6) $ 12,336 $ (13) $ 25,687 $ (19) Total $ 13,351 $ (6) $ 12,336 $ (13) $ 25,687 $ (19) December 31, 2023 Less than 12 Months Greater than 12 Months Total Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses Corporate debt securities $ 78,995 $ (152) $ 12,074 $ (54) $ 91,069 $ (206) Government and agency - U.S. 5,585 (6) — — 5,585 (6) Total $ 84,580 $ (158) $ 12,074 $ (54) $ 96,654 $ (212) As of September 30, 2024, the Company’s available-for-sale securities classified as short-term mature in one year or less and the Company’s available-for-sale securities classified as long-term mature within two years . As noted in the table above, although some of the Company’s available-for-sale marketable securities as of September 30, 2024 have been in an unrealized loss position for more than 12 months, the Company does not intend to sell these securities and it is not more likely than not that the Company will be required to sell the investments before recovery of their amortized cost bases, which may be at maturity. No credit losses were recognized on the Company’s available-for-sale securities during the three and nine months ended September 30, 2024 and 2023. The Company recorded realized gains of $0.1 million during the three and nine months ended September 30, 2024 and no realized gains or losses during the three and nine months ended September 30, 2023 .

FAIR VALUE MEASUREMENTS

FAIR VALUE MEASUREMENTS	9 Months Ended
FAIR VALUE MEASUREMENTS	Sep. 30, 2024
Fair Value Disclosures [Abstract]
FAIR VALUE MEASUREMENTS	FAIR VALUE MEASUREMENTS The Company’s financial assets and liabilities subject to fair value measurement on a recurring basis and the level of inputs used for such measurements were as follows (in thousands): Fair value measurements at reporting date using Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Fair Value at September 30, 2024 Assets included in: Cash and cash equivalents Money market securities $ 32,832 $ — $ — $ 32,832 Marketable securities Corporate debt securities — 198,674 — 198,674 Government and agency - U.S. — 27,037 — 27,037 Total fair value $ 32,832 $ 225,711 $ — $ 258,543 Liabilities included in: Debt, long-term Embedded derivatives liability $ — $ — $ 1,520 $ 1,520 Total fair value $ — $ — $ 1,520 $ 1,520 Fair value measurements at reporting date using Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Fair Value at December 31, 2023 Assets included in: Cash and cash equivalents Money market securities $ 66,207 $ — $ — $ 66,207 Marketable securities Corporate debt securities — 201,635 — 201,635 Government and agency - U.S. — 37,554 — 37,554 Total fair value $ 66,207 $ 239,189 $ — $ 305,396 Liabilities included in: Debt, long-term Embedded derivatives liability $ — $ — $ 2,560 $ 2,560 Total fair value $ — $ — $ 2,560 $ 2,560 The carrying values reported in the Company’s condensed balance sheets for cash (excluding cash equivalents, which are recorded at fair value on a recurring basis), restricted cash, accounts payable, accrued clinical trial expenses and accrued expenses and other current liabilities are reasonable estimates of their fair values due to the short-term nature of these items. The carrying amount of the Company’s long-term debt approximates fair value due to its variable market interest rate and management’s opinion that current rates and terms that would be available to the Company with the same maturity and security structure would be essentially equivalent to that of the Company’s long-term debt. Certain features of the Company’s term loan facility (the “Term Loan”) were determined to be embedded derivatives requiring separate measurement from the loan host instrument. For additional information regarding the Term Loan, see Note 6. Debt . The fair value of the Company’s money market funds is determined using quoted market prices in active markets for identical assets. The fair value for the available-for-sale marketable securities is determined based on valuation models using inputs that are observable either directly or indirectly (Level 2 inputs), such as quoted prices for similar assets or liabilities, yield curve, volatility factors, credit spreads, default rates, loss severity, current market and contractual prices for the underlying instruments or debt, broker and dealer quotes, as well as other relevant economic measures. The following table presents changes in Level 3 liabilities measured at fair value for the nine months ended September 30, 2024 (in thousands): Balance, December 31, 2023 $ 2,560 Change in fair value of embedded derivatives (1,040) Balance, September 30, 2024 $ 1,520 As of September 30, 2024 and December 31, 2023, the fair value of the embedded derivatives in the Term Loan has been estimated using the Monte Carlo model. A summary of the weighted-average significant unobservable inputs (Level 3 inputs) used in measuring the embedded derivatives in the Term Loan as of September 30, 2024 and December 31, 2023 is as follows: September 30, 2024 December 31, 2023 Conversion price $2.53 $2.53 Expected term (in years) 4.0 4.7 Expected equity volatility 102.1% 106.7% Risk-free interest rate 3.6% 3.9% Discount for lack of marketability 11.0% 11.5% Expected dividend yield 0% 0%

SUPPLEMENTAL FINANCIAL INFORMAT

SUPPLEMENTAL FINANCIAL INFORMATION	9 Months Ended
SUPPLEMENTAL FINANCIAL INFORMATION	Sep. 30, 2024
Supplemental Financial Information [Abstract]
SUPPLEMENTAL FINANCIAL INFORMATION	SUPPLEMENTAL FINANCIAL INFORMATION Prepaid expenses and other current assets consisted of the following (in thousands): September 30, 2024 December 31, 2023 Research and development service agreements $ 5,359 $ 1,680 Prepaid insurance 1,011 807 Other receivables 268 — Prepaid raw materials 143 98 Interest receivable 51 225 Other 457 283 Total prepaid expenses and other current assets $ 7,289 $ 3,093 Other assets consisted of the following (in thousands): September 30, 2024 December 31, 2023 Research and development $ 122 $ 221 Other 48 — Total other assets $ 170 $ 221 Accrued expenses and other current liabilities consisted of the following (in thousands): September 30, 2024 December 31, 2023 Compensation and other employee liabilities $ 2,778 $ 3,692 Research and development 1,706 2,186 Interest 241 249 Other 201 212 Total accrued expenses and other current liabilities $ 4,926 $ 6,339

DEBT

DEBT	9 Months Ended
DEBT	Sep. 30, 2024
Debt Disclosure [Abstract]
DEBT	DEBT On November 10, 2023, the Company entered into a Loan and Security Agreement with K2 HealthVentures LLC (the “Loan Agreement”). The Loan Agreement provided the Company with a term loan facility (the “Term Loan”) in the aggregate principal amount of $50 million, of which the Company borrowed $30 million in the first tranche upon closing. The remaining $20 million is available for borrowing upon the Company’s request based on review of certain information and discretionary approval from the lenders. The Loan Agreement bears interest per annum at the greater of (i) 9.65% or (ii) the sum of the prime rate last quoted in The Wall Street Journal plus 1.15% for such interest period and the principal amount of the Term Loan outstanding under the Loan Agreement. The Term Loan matures on November 1, 2027, and can be extended to November 1, 2028 if the Company achieves certain financing milestones. The Loan Agreement provides for a final payment fee of an additional $1.6 million (the “Final Payment”) due upon repayment of the Term Loan. The principal and interest of the Term Loan are to be repaid in equal monthly installments beginning on July 1, 2026 through the maturity of the Loan Agreement. The Loan Agreement allows prepayment of the entire Term Loan or a portion of the Term Loan of more than $5.0 million, provided that any partial prepayment will leave outstanding borrowings of at least $15.0 million. The lenders can elect to convert up to $2.5 million of the Term Loan (the “Conversion Amount”) into the Company’s common stock at a conversion price of $2.53 (the “Conversion Option”). If the lenders elect to convert the Conversion Amount upon the Next Qualified Financing, as defined in the Loan Agreement, whereby the Company receives aggregate gross proceeds of at least $20 million, the conversion price will equal the lowest effective cash price per share of securities issued in such Qualified Financing (the “Share-Settled Redemption”). The Conversion Option and Share-Settled Redemption within the Loan Agreement are required to be bifurcated as a single compound embedded derivative (the “Embedded Derivatives”) at fair value, with subsequent changes in fair value recognized in the statements of operations and comprehensive loss. In accordance with the Loan Agreement, the Company issued an equity-classified warrant to purchase 730,769 shares of common stock (the “Loan Warrant”), with an initial allocated fair value of $1.1 million. See additional discussion in Note 8. Stockholders’ Equity. The initial recognition of the direct fees of $0.5 million, the Final Payment of $1.6 million, the initial fair value of the Embedded Derivatives of $1.2 million and the fair value of the Loan Warrant of $1.1 million for the Loan Agreement resulted in a discount of $4.4 million, which is being amortized to interest expense over the term of the Loan Agreement using the effective interest method. Outstanding debt consisted of the following (in thousands): September 30, 2024 December 31, 2023 Principal value of Term Loan, including Final Payment of $1,635 $ 31,635 $ 31,635 Fair value of bifurcated embedded derivatives 1,520 2,560 Unamortized debt discount (3,481) (4,298) Total debt, long-term $ 29,674 $ 29,897 The following table provides the components of interest expense (in thousands): Three Months Ended Nine Months Ended Interest expense based on the coupon interest rate of the outstanding debt $ 739 $ 2,204 Accretion of debt discount 284 817 Total interest expense related to debt $ 1,023 $ 3,021 For the three and nine months ended September 30, 2024, the effective interest rate for the Term Loan was 13.7% and 13.5%, respectively. As of September 30, 2024, the aggregate principal payments due for the Term Loan by year are as follows (in thousands): Year ended December 31, 2026 $ 10,104 Year ended December 31, 2027 21,531 Total principal payments due for Term Loan $ 31,635 The obligations of the Company under the Loan Agreement are secured by substantially all of the assets of the Company, excluding the Company’s intellectual property.

STOCKHOLDERS_ EQUITY

STOCKHOLDERS’ EQUITY	9 Months Ended
STOCKHOLDERS’ EQUITY	Sep. 30, 2024
Stockholders' Equity Note [Abstract]
STOCKHOLDERS’ EQUITY	STOCKHOLDERS’ EQUITY Authorized Shares As of September 30, 2024, the total number of shares of capital stock authorized to be issued per the Company’s Amended and Restated Certificate of Incorporation is 310,000,000, with 10,000,000 shares designated as preferred stock with a par value of $0.0001 per share, and 300,000,000 shares designated as common stock with a par value of $0.0001 per share. Each share of common stock is entitled to one vote. Shelf Registration and Equity Offerings On July 1, 2022, the Company filed a shelf registration statement on Form S-3 (the “2022 Registration Statement”). Pursuant to the 2022 Registration Statement, the Company may offer and sell securities having an aggregate public offering price of up to $200.0 million. On July 21, 2023, the Company issued 16,774,193 shares of common stock at a price of $7.75 per share (the “Offering”). The net proceeds from the Offering, after underwriting discounts and commissions and other offering expenses, were $121.9 million. In connection with the filing of the 2022 Registration Statement, the Company also entered into a sales agreement (the “Sales Agreement”) with BofA Securities, Inc. (“BofA”) and Stifel, Nicolaus & Company, Incorporated (“Stifel”) as sales agents, pursuant to which the Company may issue and sell shares of its common stock for an aggregate offering price of up to $50.0 million under an at-the-market offering program (the “ATM”), which is included in the $200.0 million of securities that may be offered pursuant to the 2022 Registration Statement. On April 23, 2023, the Company entered into an amendment to the Sales Agreement (as amended, the “Amended Sales Agreement”) to add BTIG, LLC (“BTIG”) as a sales agent under the Amended Sales Agreement (BTIG, together with BofA and Stifel, the “Sales Agents”). Pursuant to the Amended Sales Agreement, the Company will pay the Sales Agents a commission rate of up to 3.0% of the gross proceeds from the sale of any shares of common stock under the ATM. The Company is not obligated to make any sales of shares of its common stock under the ATM. During the nine months ended September 30, 2024, the Company issued and sold 2,068,246 shares of common stock under the ATM for net proceeds of $7.9 million, or $3.84 per share. The Company has issued shares of common stock for aggregate gross proceeds of $12.2 million under the ATM since the program’s inception. On March 27, 2024, the Company filed a shelf registration statement on Form S-3 (the “2024 Registration Statement”). Pursuant to the 2024 Registration Statement, the Company may offer and sell securities having an aggregate public offering price of up to $200.0 million. Common Stock Warrant

STOCK-BASED COMPENSATION

STOCK-BASED COMPENSATION	9 Months Ended
STOCK-BASED COMPENSATION	Sep. 30, 2024
Share-Based Payment Arrangement [Abstract]
STOCK-BASED COMPENSATION	STOCK-BASED COMPENSATION 2021 Equity Incentive Plan The 2021 Equity Incentive Plan (the “2021 Plan”), which provides for the grant of incentive stock options to employees and the grant of nonstatutory stock options, stock appreciation rights, restricted stock awards, restricted stock unit awards, performance awards and other forms of stock awards to employees, directors and consultants, became effective on June 30, 2021. The 2021 Plan is a successor to the Company’s Amended and Restated Stock Performance Plan that was adopted by the Company’s Board of Directors (the “Board”) and stockholders on April 8, 2013 (as amended from time to time, most recently on November 20, 2020, the “2013 Plan”). The maximum number of shares of common stock that may be issued upon the exercise of incentive stock options under the 2021 Plan is 12,000,000 shares. Following the effectiveness of the 2021 Plan, no further grants may be made under the 2013 Plan; however, any outstanding equity awards granted under the 2013 Plan continue to be governed by the terms of the 2013 Plan. As of September 30, 2024, there were 3,227,248 options outstanding under the 2013 Plan. The number of shares of common stock reserved for issuance under the 2021 Plan automatically increases on January 1 of each calendar year through January 1, 2031, in an amount equal to 5% of the total number of shares of common stock outstanding on December 31 of the fiscal year before the date of each automatic increase, or a lesser number of shares determined by the Board prior to the applicable January 1. On January 1, 2024, the number of shares of common stock reserved for issuance under the 2021 Plan automatically increased by 2,895,523 shares. As of September 30, 2024, a total of 14,668,721 shares were authorized for issuance under the 2021 Plan and 2,535,928 shares remained available for issuance under the 2021 Plan. The Company recorded stock-based compensation expense in the following expense categories of its condensed statements of operations for the periods shown (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2024 2023 2024 2023 General and administrative $ 1,436 $ 1,127 $ 4,678 $ 3,143 Research and development 902 473 2,614 1,368 Total stock-based compensation $ 2,338 $ 1,600 $ 7,292 $ 4,511 Stock Options The Black-Scholes option-pricing model was used to estimate the fair value of stock options granted during the nine months ended September 30, 2024 and 2023 with the following weighted average assumptions: Nine Months Ended September 30, 2024 2023 Risk-free interest rate 3.81% - 5.10% 3.47% - 4.43% Expected term (in years) 0.9 - 6.1 5.5 - 6.1 Expected volatility 92% - 103% 90% - 98% Expected dividend yield 0% 0% The weighted average grant date fair value of options granted during the nine months ended September 30, 2024 and 2023 was $2.93 per share and $4.53 per share, respectively. Stock options granted after December 31, 2017 generally vest monthly over a range of 12 to 48 months or vest monthly over a total of 48 months following a one-year cliff and all have a 10-year contractual term. Beginning in 2022, the Company has also issued annual option awards to its Board that vest in full on the first anniversary of the grant date. Stock options granted prior to December 31, 2017 were either fully vested upon grant or generally vested monthly over a range of three The following table reflects summarized stock option activity: Stock Options Weighted Average Exercise Price Weighted Average Remaining Contractual Life (in years) Aggregate Intrinsic Value (in thousands) Outstanding as of December 31, 2023 7,523,947 $ 4.01 Granted 2,961,850 $ 3.71 Forfeited (57,871) $ 7.36 Expired (53,555) $ 9.10 Outstanding as of September 30, 2024 10,374,371 $ 3.88 7.7 $ 4,461 Vested and exercisable as of September 30, 2024 5,664,870 $ 3.48 6.8 $ 4,186 As of September 30, 2024, total unrecognized compensation costs related to unvested stock option awards were approximately $15.1 million, which the Company expects to recognize over a weighted-average period of approximately 2.5 years. Restricted Stock Units In each of January 2024 and 2023, the Company granted a restricted stock unit (“RSU”) award to each of its then-current employees. These RSU awards vest in equal annual installments on the first three Number of Shares Weighted Average Grant Date Fair Value Unvested as of December 31, 2023 328,500 $ 6.11 Granted 1,204,640 $ 4.15 Vested (109,493) $ 6.11 Forfeited (12,317) $ 4.59 Unvested as of September 30, 2024 1,411,330 $ 4.45 As of September 30, 2024, total unrecognized compensation costs related to unvested RSUs were approximately $4.6 million, which the Company expects to recognize over a weighted-average period of approximately 2.1 years. Employee Stock Purchase Plan

COMMITMENTS AND CONTINGENCIES

COMMITMENTS AND CONTINGENCIES	9 Months Ended
COMMITMENTS AND CONTINGENCIES	Sep. 30, 2024
Commitments and Contingencies Disclosure [Abstract]
COMMITMENTS AND CONTINGENCIES	COMMITMENTS AND CONTINGENCIES The Company is not a party to any material legal proceedings and is not aware of any pending or threatened claims. From time to time, the Company may be subject to various legal proceedings and claims that arise in the ordinary course of its business activities. In November 2023, the Company entered into a Non-exclusive Collaboration and License Agreement (the “Halozyme License Agreement”) with Halozyme, Inc. (“Halozyme”). Under the terms of the Halozyme License Agreement, Halozyme granted the Company a non-exclusive license to Halozyme’s drug delivery technology for the development of a subcutaneous formulation of sabirnetug (such combination, the “Halozyme Product”). In January 2024, the Company paid a seven-figure upfront license payment for the Halozyme Product, which was included in accrued expenses and other current liabilities as of December 31, 2023. Additionally, the Company will make milestone payments tied to achievement of certain development and commercialization milestone events with respect to the Halozyme Product, as well as milestone payments based on achievement of certain net sales levels of the Halozyme Product. The Company will also make single-digit royalty payments based on worldwide net sales of the Halozyme Product. The upfront license payment and milestones are recorded as in-process research and development expense when incurred. In November 2022, the Company entered into a License Agreement (“Lonza License Agreement”) with Lonza Sales AG (“Lonza”). Under the terms of the Lonza License Agreement, Lonza granted the Company a worldwide non-exclusive license to use Lonza’s glutamine synthetase gene expression system to manufacture and commercialize sabirnetug (the “Lonza Product”). Under the terms of the Lonza License Agreement, in consideration of the licenses and consents granted to the Company, the Company paid an upfront fee of 1.0 million Swiss Francs. The Company is also required to pay certain royalties upon commercialization and annual payments on a country-by-country basis in respect of the manufacturing and sale of the Lonza Product, which include (i) a royalty of less than 1% on net sales where Lonza manufactures the Lonza Product, (ii) an annual royalty payment in Swiss Francs in the low six-digits and a royalty of less than 1% on net sales where the Company manufactures the Lonza Product and (iii) an annual payment in Swiss Francs in the mid-six-digits per sublicense and a royalty on net sales in the low single digits where a third party manufactures the Lonza Product. These payment obligations expire 10 years from the first commercial sales of the Lonza Product in such country of sale.

NET LOSS PER SHARE

NET LOSS PER SHARE	9 Months Ended
NET LOSS PER SHARE	Sep. 30, 2024
Earnings Per Share [Abstract]
NET LOSS PER SHARE	NET LOSS PER SHARE Basic net loss per share of common stock is computed by dividing net loss by the weighted-average number of shares of common stock outstanding during the period. Basic and diluted net loss per share was the same for each period presented as the inclusion of all potential common stock outstanding would have been anti-dilutive. Potentially dilutive securities not included in the calculation of diluted net loss per common share, because to do so would be anti-dilutive, were as follows for the periods presented: September 30, 2024 2023 Shares issuable upon exercise of stock options 10,374,371 7,400,147 Shares issuable upon conversion election for Term Loan 988,142 — Shares issuable upon exercise of warrant 730,769 — Unvested RSUs 1,411,330 328,500 Total 13,504,612 7,728,647

Pay vs Performance Disclosure

Pay vs Performance Disclosure - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
Pay vs Performance Disclosure - USD ($) $ in Thousands	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Pay vs Performance Disclosure
Net loss	$ (29,765)	$ (12,957)	$ (65,175)	$ (35,874)

Insider Trading Arrangements

Insider Trading Arrangements	3 Months Ended	9 Months Ended
Insider Trading Arrangements	Sep. 30, 2024 shares	Sep. 30, 2024 shares
Trading Arrangements, by Individual
Non-Rule 10b5-1 Arrangement Adopted	false
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false
Matthew Zuga [Member]
Trading Arrangements, by Individual
Material Terms of Trading Arrangement		On August 30, 2024, Matthew Zuga, our Chief Financial Officer and Chief Business Officer, entered into a Rule 10b5-1 trading plan that provides that Mr. Zuga, acting through a broker, may sell the number of shares of common stock sufficient to cover the taxes solely associated with the vesting of up to 128,334 restricted stock unit (“RSU”) awards granted to Mr. Zuga as equity compensation, which sales may occur from January 3, 2025 to December 31, 2027. On September 24, 2024, Mr. Zuga entered into a separate 10b5-1 trading plan that provides that Mr. Zuga, acting through a broker, may sell (1) up to 83,110 shares of common stock, which sales may occur from January 23, 2025 through January 16, 2026; (2) 594,663 shares of common stock received upon the exercise of option awards granted to Mr. Zuga as equity incentive compensation, which sales may occur from January 23, 2025 through January 16, 2026; and (3) 46,501 shares of common stock received upon the vesting of RSU awards granted to Mr. Zuga as equity incentive compensation, which sales may occur from January 23, 2025 to January 16, 2026.
Name	Matthew Zuga
Title	Chief Financial Officer and Chief Business Officer
Rule 10b5-1 Arrangement Adopted	true
Adoption Date	August 30, 2024
Arrangement Duration	1092 days
Aggregate Available	128,334	128,334
Russell Barton [Member]
Trading Arrangements, by Individual
Material Terms of Trading Arrangement		On August 31, 2024, Russell Barton, our Chief Operating Officer, entered into a Rule 10b5-1 trading plan that provides that Mr. Barton, acting through a broker, may sell the number of shares of common stock sufficient to cover the taxes associated with the vesting of up to 90,800 RSU awards granted to Mr. Barton as equity compensation, which sales may occur from January 3, 2025 to December 31, 2027.
Name	Russell Barton
Title	Chief Operating Officer
Rule 10b5-1 Arrangement Adopted	true
Adoption Date	August 31, 2024
Expiration Date	December 31, 2027
Arrangement Duration	1092 days
Aggregate Available	90,800	90,800
Eric Siemers [Member]
Trading Arrangements, by Individual
Material Terms of Trading Arrangement		On September 3, 2024, Eric Siemers, M.D., our Chief Medical Officer, entered into a Rule 10b5-1 trading plan that provides that Dr. Siemers, acting through a broker, may sell the number of shares of common stock sufficient to cover the taxes associated with the vesting of up to 111,800 RSU awards granted to Dr. Siemers as equity compensation, which sales may occur from January 3, 2025 to December 31, 2027.
Name	Eric Siemers
Title	Chief Medical Officer
Rule 10b5-1 Arrangement Adopted	true
Adoption Date	September 3, 2024
Expiration Date	December 31, 2027
Arrangement Duration	1092 days
Aggregate Available	111,800	111,800
Matthew Zuga, Common Stock, Taxes, Vesting Of Restricted Stock Units [Member] \| Matthew Zuga [Member]
Trading Arrangements, by Individual
Expiration Date	December 31, 2027
Matthew Zuga, Common Stock, Vesting Of Restricted Stock Unit [Member] \| Matthew Zuga [Member]
Trading Arrangements, by Individual
Rule 10b5-1 Arrangement Adopted	true
Adoption Date	September 24, 2024
Expiration Date	January 16, 2026
Arrangement Duration	358 days
Aggregate Available	46,501	46,501
Matthew Zuga, Common Stock, Exercise Of Option Awards [Member] \| Matthew Zuga [Member]
Trading Arrangements, by Individual
Rule 10b5-1 Arrangement Adopted	true
Adoption Date	September 24, 2024
Expiration Date	January 16, 2026
Arrangement Duration	358 days
Aggregate Available	594,663	594,663
Matthew Zuga, Common Stock [Member] \| Matthew Zuga [Member]
Trading Arrangements, by Individual
Rule 10b5-1 Arrangement Adopted	true
Adoption Date	September 24, 2024
Expiration Date	January 16, 2026
Arrangement Duration	358 days
Aggregate Available	83,110	83,110

BASIS OF PRESENTATION AND SUM_2

BASIS OF PRESENTATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)	9 Months Ended
	Sep. 30, 2024
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying unaudited condensed financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”) for interim financial information, the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the information and notes required by U.S. GAAP for complete financial statements. In the opinion of management, the unaudited condensed financial statements reflect all adjustments, which include only normal recurring adjustments, necessary to present fairly the Company’s financial position and results of its operations and its cash flows for the periods presented. Certain information and note disclosures normally included in the Company’s annual financial statements prepared in accordance with U.S. GAAP have been condensed or omitted. These unaudited condensed financial statement results are not necessarily indicative of results to be expected for the full fiscal year or any future period.
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the unaudited condensed financial statements, as well as the reported amounts of expenses during the reporting periods. These estimates and assumptions are based on the Company’s historical experience, and on various other factors that management believes are reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities and the recording of expenses that are not readily apparent from other sources. Actual results may differ from these estimates under different assumptions or conditions. To the extent there are material differences between the estimates and actual results, the Company’s future results of operations will be affected. The more significant estimates and assumptions by management include, among others: the valuation allowance of deferred tax assets resulting from net operating losses, the valuation of stock options and the valuation of embedded derivatives within the Company’s long-term debt.
Cash and Cash Equivalents and Restricted Cash	Cash and Cash Equivalents and Restricted Cash Restricted cash primarily consists of deposited cash collateral for the Company’s credit card program.
Recently Issued Accounting Pronouncements	Recently Issued Accounting Pronouncements From time to time, new accounting pronouncements are issued by the Financial Accounting Standards Board (“FASB”) or other standard setting bodies that the Company adopts as of the specified effective date. Unless otherwise discussed below, the Company does not believe that the adoption of recently issued standards have or may have a material impact on its financial statements and disclosures. In November 2023, the FASB issued Accounting Standards Update (“ASU”) 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures. The standard is intended to improve financing reporting by requiring disclosure of incremental segment information on an annual and interim basis for all public entities to enable investors to develop more decision-useful financial analyses. The standard is effective for fiscal years beginning after December 31, 2023, and interim periods within fiscal years beginning after December 15, 2024. Upon adoption, the standard should be applied retrospectively to all prior periods presented in the financial statements. The Company is evaluating the potential impact of this adoption on its financial statements and related disclosures. In December 2023, the FASB issued ASU 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures. The standard is intended to enhance the existing income tax disclosures to provide information to better assess how an entity’s operations and related tax risks and tax planning and operational opportunities affect its tax rate and prospects for future cash flows. The standard is effective for annual periods beginning after December 15, 2024. Upon adoption, the standard should be applied on a prospective basis, although retrospective application is permitted. Early adoption is also permitted. The Company is evaluating the potential impact of this adoption on the financial statements and related disclosures. In November 2024, the FASB issued ASU 2024-03, Income Statement – Reporting Comprehensive Income – Expense Disaggregation Disclosures (Subtopic 220-40): Disaggregation of Income Statement Expenses. The standard is intended to require more detailed disclosures about specified categories of expenses, including employee compensation, depreciation and amortization, included in certain expense captions presented on the face of the income statement. The ASU is effective for fiscal years beginning after December 15, 2026, and for interim periods within fiscal years beginning after December 31, 2027. Early adoption is permitted. The amendments may be applied either (1) prospectively to financial statements issued for reporting periods after the effective date of this ASU or (2) retrospectively to all prior periods presented in the financial statements. The Company is evaluating the potential impact of this adoption on the financial statements and related disclosures.

BASIS OF PRESENTATION AND SUM_3

BASIS OF PRESENTATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Tables)	9 Months Ended
	Sep. 30, 2024
Accounting Policies [Abstract]
Schedule of Cash, Cash Equivalents and Restricted Cash	The following table provides a reconciliation of cash, cash equivalents and restricted cash from the balance sheets to the statements of cash flows (in thousands): September 30, 2024 December 31, 2023 Cash and cash equivalents $ 33,184 $ 66,886 Restricted cash 236 233 Total cash, cash equivalents and restricted cash $ 33,420 $ 67,119

MARKETABLE SECURITIES (Tables)

MARKETABLE SECURITIES (Tables)	9 Months Ended
MARKETABLE SECURITIES (Tables)	Sep. 30, 2024
Marketable Securities [Abstract]
Summary of Marketable Securities	The Company’s marketable securities consisted of the following (in thousands): September 30, 2024 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Available-for-sale securities, short-term Corporate debt securities $ 139,840 $ 300 $ (18) $ 140,122 Government and agency - U.S. 26,979 58 — 27,037 Total available-for-sale securities, short-term 166,819 358 (18) 167,159 Available-for-sale securities, long-term Corporate debt securities 58,374 179 (1) 58,552 Total available-for-sale securities, long-term 58,374 179 (1) 58,552 Total available-for-sale securities $ 225,193 $ 537 $ (19) $ 225,711 December 31, 2023 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Available-for-sale securities, short-term Corporate debt securities $ 144,184 $ 97 $ (191) $ 144,090 Government and agency - U.S. 32,470 82 (6) 32,546 Total available-for-sale securities, short-term 176,654 179 (197) 176,636 Available-for-sale securities, long-term Corporate debt securities 57,240 320 (15) 57,545 Government and agency - U.S. 4,985 23 — 5,008 Total available-for-sale securities, long-term 62,225 343 (15) 62,553 Total available-for-sale securities $ 238,879 $ 522 $ (212) $ 239,189
Summary of Unrealized Losses	The following tables summarize the amount of unrealized losses, defined as the amount by which the amortized cost exceeds fair value, and the related fair value of available-for-sale marketable securities with unrealized losses, which have been segregated into two categories: those that have been in a continuous unrealized loss position for less than 12 months and those that have been in a continuous unrealized loss position for 12 or more months (in thousands): September 30, 2024 Less than 12 Months Greater than 12 Months Total Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses Corporate debt securities $ 13,351 $ (6) $ 12,336 $ (13) $ 25,687 $ (19) Total $ 13,351 $ (6) $ 12,336 $ (13) $ 25,687 $ (19) December 31, 2023 Less than 12 Months Greater than 12 Months Total Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses Corporate debt securities $ 78,995 $ (152) $ 12,074 $ (54) $ 91,069 $ (206) Government and agency - U.S. 5,585 (6) — — 5,585 (6) Total $ 84,580 $ (158) $ 12,074 $ (54) $ 96,654 $ (212)

FAIR VALUE MEASUREMENTS (Tables

FAIR VALUE MEASUREMENTS (Tables)	9 Months Ended
FAIR VALUE MEASUREMENTS (Tables)	Sep. 30, 2024
Fair Value Disclosures [Abstract]
Summary of Fair Value, Assets and Liabilities Measured on Recurring Basis	The Company’s financial assets and liabilities subject to fair value measurement on a recurring basis and the level of inputs used for such measurements were as follows (in thousands): Fair value measurements at reporting date using Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Fair Value at September 30, 2024 Assets included in: Cash and cash equivalents Money market securities $ 32,832 $ — $ — $ 32,832 Marketable securities Corporate debt securities — 198,674 — 198,674 Government and agency - U.S. — 27,037 — 27,037 Total fair value $ 32,832 $ 225,711 $ — $ 258,543 Liabilities included in: Debt, long-term Embedded derivatives liability $ — $ — $ 1,520 $ 1,520 Total fair value $ — $ — $ 1,520 $ 1,520 Fair value measurements at reporting date using Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Fair Value at December 31, 2023 Assets included in: Cash and cash equivalents Money market securities $ 66,207 $ — $ — $ 66,207 Marketable securities Corporate debt securities — 201,635 — 201,635 Government and agency - U.S. — 37,554 — 37,554 Total fair value $ 66,207 $ 239,189 $ — $ 305,396 Liabilities included in: Debt, long-term Embedded derivatives liability $ — $ — $ 2,560 $ 2,560 Total fair value $ — $ — $ 2,560 $ 2,560
Schedule of the Fair Value using Level 3 Significant Unobservable Inputs	The following table presents changes in Level 3 liabilities measured at fair value for the nine months ended September 30, 2024 (in thousands): Balance, December 31, 2023 $ 2,560 Change in fair value of embedded derivatives (1,040) Balance, September 30, 2024 $ 1,520
Schedule of Estimate of Fair Value in Embedded Derivatives in Term Loan	As of September 30, 2024 and December 31, 2023, the fair value of the embedded derivatives in the Term Loan has been estimated using the Monte Carlo model. A summary of the weighted-average significant unobservable inputs (Level 3 inputs) used in measuring the embedded derivatives in the Term Loan as of September 30, 2024 and December 31, 2023 is as follows: September 30, 2024 December 31, 2023 Conversion price $2.53 $2.53 Expected term (in years) 4.0 4.7 Expected equity volatility 102.1% 106.7% Risk-free interest rate 3.6% 3.9% Discount for lack of marketability 11.0% 11.5% Expected dividend yield 0% 0%

SUPPLEMENTAL FINANCIAL INFORM_2

SUPPLEMENTAL FINANCIAL INFORMATION (Tables)	9 Months Ended
SUPPLEMENTAL FINANCIAL INFORMATION (Tables)	Sep. 30, 2024
Supplemental Financial Information [Abstract]
Summary of Prepaid Expenses and Other Current Assets	Prepaid expenses and other current assets consisted of the following (in thousands): September 30, 2024 December 31, 2023 Research and development service agreements $ 5,359 $ 1,680 Prepaid insurance 1,011 807 Other receivables 268 — Prepaid raw materials 143 98 Interest receivable 51 225 Other 457 283 Total prepaid expenses and other current assets $ 7,289 $ 3,093
Schedule of Other Assets	Other assets consisted of the following (in thousands): September 30, 2024 December 31, 2023 Research and development $ 122 $ 221 Other 48 — Total other assets $ 170 $ 221
Summary of Accrued Expenses and Other Current Liabilities	Accrued expenses and other current liabilities consisted of the following (in thousands): September 30, 2024 December 31, 2023 Compensation and other employee liabilities $ 2,778 $ 3,692 Research and development 1,706 2,186 Interest 241 249 Other 201 212 Total accrued expenses and other current liabilities $ 4,926 $ 6,339

DEBT (Tables)

DEBT (Tables)	9 Months Ended
DEBT (Tables)	Sep. 30, 2024
Debt Disclosure [Abstract]
Summary of Outstanding Debt and Interest Expense	Outstanding debt consisted of the following (in thousands): September 30, 2024 December 31, 2023 Principal value of Term Loan, including Final Payment of $1,635 $ 31,635 $ 31,635 Fair value of bifurcated embedded derivatives 1,520 2,560 Unamortized debt discount (3,481) (4,298) Total debt, long-term $ 29,674 $ 29,897 The following table provides the components of interest expense (in thousands): Three Months Ended Nine Months Ended Interest expense based on the coupon interest rate of the outstanding debt $ 739 $ 2,204 Accretion of debt discount 284 817 Total interest expense related to debt $ 1,023 $ 3,021
Summary of Aggregate Principal Payments	As of September 30, 2024, the aggregate principal payments due for the Term Loan by year are as follows (in thousands): Year ended December 31, 2026 $ 10,104 Year ended December 31, 2027 21,531 Total principal payments due for Term Loan $ 31,635

STOCK-BASED COMPENSATION (Table

STOCK-BASED COMPENSATION (Tables)	9 Months Ended
STOCK-BASED COMPENSATION (Tables)	Sep. 30, 2024
Share-Based Payment Arrangement [Abstract]
Summary of Share-Based Compensation Expense Related to Stock Options	The Company recorded stock-based compensation expense in the following expense categories of its condensed statements of operations for the periods shown (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2024 2023 2024 2023 General and administrative $ 1,436 $ 1,127 $ 4,678 $ 3,143 Research and development 902 473 2,614 1,368 Total stock-based compensation $ 2,338 $ 1,600 $ 7,292 $ 4,511
Summary of Assumptions Used for Valuation of Fair Value of Stock Options	The Black-Scholes option-pricing model was used to estimate the fair value of stock options granted during the nine months ended September 30, 2024 and 2023 with the following weighted average assumptions: Nine Months Ended September 30, 2024 2023 Risk-free interest rate 3.81% - 5.10% 3.47% - 4.43% Expected term (in years) 0.9 - 6.1 5.5 - 6.1 Expected volatility 92% - 103% 90% - 98% Expected dividend yield 0% 0%
Summary of Stock Option Activity	The following table reflects summarized stock option activity: Stock Options Weighted Average Exercise Price Weighted Average Remaining Contractual Life (in years) Aggregate Intrinsic Value (in thousands) Outstanding as of December 31, 2023 7,523,947 $ 4.01 Granted 2,961,850 $ 3.71 Forfeited (57,871) $ 7.36 Expired (53,555) $ 9.10 Outstanding as of September 30, 2024 10,374,371 $ 3.88 7.7 $ 4,461 Vested and exercisable as of September 30, 2024 5,664,870 $ 3.48 6.8 $ 4,186
Summary of Nonvested Restricted Stock Units Activity	Number of Shares Weighted Average Grant Date Fair Value Unvested as of December 31, 2023 328,500 $ 6.11 Granted 1,204,640 $ 4.15 Vested (109,493) $ 6.11 Forfeited (12,317) $ 4.59 Unvested as of September 30, 2024 1,411,330 $ 4.45

NET LOSS PER SHARE (Tables)

NET LOSS PER SHARE (Tables)	9 Months Ended
NET LOSS PER SHARE (Tables)	Sep. 30, 2024
Earnings Per Share [Abstract]
Summary of Antidilutive Securities Excluded from Computation of Loss Per Share	Potentially dilutive securities not included in the calculation of diluted net loss per common share, because to do so would be anti-dilutive, were as follows for the periods presented: September 30, 2024 2023 Shares issuable upon exercise of stock options 10,374,371 7,400,147 Shares issuable upon conversion election for Term Loan 988,142 — Shares issuable upon exercise of warrant 730,769 — Unvested RSUs 1,411,330 328,500 Total 13,504,612 7,728,647

DESCRIPTION OF ORGANIZATION A_2

DESCRIPTION OF ORGANIZATION AND BUSINESS OPERATIONS (Details) $ in Thousands	Sep. 30, 2024 USD ($)	Dec. 31, 2023 USD ($)	Jul. 31, 2023 participant	Jun. 30, 2023 participant patient
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Accumulated deficit \| $	$ 287,973	$ 222,798
Working capital \| $	$ 187,700	$ 233,600
Number of patients enrolled in trail \| patient				65
Number of patients enrolled in trial with one dose of study drug received \| participant				62
Number of participants enrolled in trial with one dose of study drug received with primary and secondary objectives met \| participant			62

BASIS OF PRESENTATION AND SUM_4

BASIS OF PRESENTATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Additional Information (Details) - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023
Accounting Policies [Abstract]
Cash equivalents	$ 32.8	$ 66.2

BASIS OF PRESENTATION AND SUM_5

BASIS OF PRESENTATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Schedule of Cash, Cash Equivalents and Restricted Cash (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023	Sep. 30, 2023	Dec. 31, 2022
Accounting Policies [Abstract]
Cash and cash equivalents	$ 33,184	$ 66,886
Restricted cash	236	233
Total cash, cash equivalents and restricted cash	$ 33,420	$ 67,119	$ 95,106	$ 130,101

MARKETABLE SECURITIES - Summary

MARKETABLE SECURITIES - Summary of Marketable Securities (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Amortized Cost
Amortized Cost	$ 166,819	$ 176,654
Amortized Cost	58,374	62,225
Amortized Cost	225,193	238,879
Gross Unrealized Gains
Gross Unrealized Gains	358	179
Gross Unrealized Gains	179	343
Gross Unrealized Gains	537	522
Gross Unrealized Losses
Gross Unrealized Losses	(18)	(197)
Gross Unrealized Losses	(1)	(15)
Gross Unrealized Losses	(19)	(212)
Fair Value
Fair Value	167,159	176,636
Fair Value	58,552	62,553
Fair Value	225,711	239,189
Corporate debt securities
Amortized Cost
Amortized Cost	139,840	144,184
Amortized Cost	58,374	57,240
Gross Unrealized Gains
Gross Unrealized Gains	300	97
Gross Unrealized Gains	179	320
Gross Unrealized Losses
Gross Unrealized Losses	(18)	(191)
Gross Unrealized Losses	(1)	(15)
Fair Value
Fair Value	140,122	144,090
Fair Value	58,552	57,545
Government and agency - U.S.
Amortized Cost
Amortized Cost	26,979	32,470
Amortized Cost		4,985
Gross Unrealized Gains
Gross Unrealized Gains	58	82
Gross Unrealized Gains		23
Gross Unrealized Losses
Gross Unrealized Losses	0	(6)
Gross Unrealized Losses		0
Fair Value
Fair Value	$ 27,037	32,546
Fair Value		$ 5,008

MARKETABLE SECURITIES - Summa_2

MARKETABLE SECURITIES - Summary of Unrealized Loss on Investments (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Less than 12 Months
Fair Value	$ 13,351	$ 84,580
Unrealized Losses	(6)	(158)
Greater than 12 Months
Fair Value	12,336	12,074
Unrealized Losses	(13)	(54)
Total
Fair Value	25,687	96,654
Unrealized Losses	(19)	(212)
Corporate debt securities
Less than 12 Months
Fair Value	13,351	78,995
Unrealized Losses	(6)	(152)
Greater than 12 Months
Fair Value	12,336	12,074
Unrealized Losses	(13)	(54)
Total
Fair Value	25,687	91,069
Unrealized Losses	$ (19)	(206)
Government and agency - U.S.
Less than 12 Months
Fair Value		5,585
Unrealized Losses		(6)
Greater than 12 Months
Fair Value		0
Unrealized Losses		0
Total
Fair Value		5,585
Unrealized Losses		$ (6)

MARKETABLE SECURITIES - Additio

MARKETABLE SECURITIES - Additional Information (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Marketable Securities [Line Items]
Debt securities, available-for-sale, noncurrent, term (in years)			2 years
Debt securities, available-for-sale, allowance for credit loss	$ 0	$ 0	$ 0	$ 0
Debt securities, available-for-sale, realized gain (loss)	$ 100,000	$ 0	$ 100,000	$ 0
Maximum
Marketable Securities [Line Items]
Debt securities, available-for-sale, current, term (in years)			1 year
Minimum
Marketable Securities [Line Items]
Debt securities, available-for-sale, unrealized loss position period (in months)			12 months

FAIR VALUE MEASUREMENTS - Summa

FAIR VALUE MEASUREMENTS - Summary of Fair Value, Assets and Liabilities Measured on Recurring Basis (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Marketable securities
Total fair value	$ 258,543	$ 305,396
Debt, long-term
Embedded derivatives liability	1,520	2,560
Total fair value	1,520	2,560
Corporate debt securities
Marketable securities
Marketable securities	198,674	201,635
Government and agency - U.S.
Marketable securities
Marketable securities	27,037	37,554
Quoted Prices in Active Markets for Identical Assets (Level 1)
Marketable securities
Total fair value	32,832	66,207
Debt, long-term
Embedded derivatives liability	0	0
Total fair value	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) \| Corporate debt securities
Marketable securities
Marketable securities	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) \| Government and agency - U.S.
Marketable securities
Marketable securities	0	0
Significant Other Observable Inputs (Level 2)
Marketable securities
Total fair value	225,711	239,189
Debt, long-term
Embedded derivatives liability	0	0
Total fair value	0	0
Significant Other Observable Inputs (Level 2) \| Corporate debt securities
Marketable securities
Marketable securities	198,674	201,635
Significant Other Observable Inputs (Level 2) \| Government and agency - U.S.
Marketable securities
Marketable securities	27,037	37,554
Significant Unobservable Inputs (Level 3)
Marketable securities
Total fair value	0	0
Debt, long-term
Embedded derivatives liability	1,520	2,560
Total fair value	1,520	2,560
Significant Unobservable Inputs (Level 3) \| Corporate debt securities
Marketable securities
Marketable securities	0	0
Significant Unobservable Inputs (Level 3) \| Government and agency - U.S.
Marketable securities
Marketable securities	0	0
Money market securities
Cash and cash equivalents
Cash and cash equivalents	32,832	66,207
Money market securities \| Quoted Prices in Active Markets for Identical Assets (Level 1)
Cash and cash equivalents
Cash and cash equivalents	32,832	66,207
Money market securities \| Significant Other Observable Inputs (Level 2)
Cash and cash equivalents
Cash and cash equivalents	0	0
Money market securities \| Significant Unobservable Inputs (Level 3)
Cash and cash equivalents
Cash and cash equivalents	$ 0	$ 0

FAIR VALUE MEASUREMENTS - Sched

FAIR VALUE MEASUREMENTS - Schedule of the Fair Value using Level 3 Significant Unobservable Inputs (Details) - Embedded Derivative Financial Instruments $ in Thousands	9 Months Ended
	Sep. 30, 2024 USD ($)
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	$ 2,560
Change in fair value of embedded derivatives	(1,040)
Ending balance	$ 1,520

FAIR VALUE MEASUREMENTS - Sch_2

FAIR VALUE MEASUREMENTS - Schedule of Estimate of Fair Value in Embedded Derivatives in Term Loan (Details)	Sep. 30, 2024 $ / shares	Dec. 31, 2023 $ / shares
Conversion price
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	2.53	2.53
Expected term (in years)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	4	4.7
Expected equity volatility
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	1.021	1.067
Risk-free interest rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	0.036	0.039
Discount for lack of marketability
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	0.110	0.115
Expected dividend yield
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	0	0

SUPPLEMENTAL FINANCIAL INFORM_3

SUPPLEMENTAL FINANCIAL INFORMATION - Summary of Prepaid Expenses and Other Current Assets (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Supplemental Financial Information [Abstract]
Research and development service agreements	$ 5,359	$ 1,680
Prepaid insurance	1,011	807
Other receivables	268	0
Prepaid raw materials	143	98
Interest receivable	51	225
Other	457	283
Total prepaid expenses and other current assets	$ 7,289	$ 3,093

SUPPLEMENTAL FINANCIAL INFORM_4

SUPPLEMENTAL FINANCIAL INFORMATION - Summary of Other Assets (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Supplemental Financial Information [Abstract]
Research and development	$ 122	$ 221
Other	48	0
Total other assets	$ 170	$ 221

SUPPLEMENTAL FINANCIAL INFORM_5

SUPPLEMENTAL FINANCIAL INFORMATION - Summary of Accrued Expenses and Other Current Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Supplemental Financial Information [Abstract]
Compensation and other employee liabilities	$ 2,778	$ 3,692
Research and development	1,706	2,186
Interest	241	249
Other	201	212
Total accrued expenses and other current liabilities	$ 4,926	$ 6,339

DEBT- Additional Information (D

DEBT- Additional Information (Details) - USD ($)		3 Months Ended	9 Months Ended
DEBT- Additional Information (Details) - USD ($)	Nov. 10, 2023	Sep. 30, 2024	Sep. 30, 2024	Dec. 31, 2023
Debt Instrument, Redemption [Line Items]
Fair value of bifurcated embedded derivatives		$ 1,520,000	$ 1,520,000	$ 2,560,000
Common Stock Warrants \| Common Stock
Debt Instrument, Redemption [Line Items]
Warrants (in shares)	730,769
Term Loan \| Secured Debt
Debt Instrument, Redemption [Line Items]
Borrowing capacity	$ 50,000,000
Interest rate	9.65%
Variable interest rate	1.15%
Final payment fee	$ 1,600,000	1,635,000	1,635,000
Minimum required payment (more than)	5,000,000
Minimum required payment, outstanding debt requirement (at least)	15,000,000
Conversion, if-converted amount	$ 2,500,000
Conversion price (in dollars per share)	$ 2.53
Direct fees	$ 500,000
Fair value of bifurcated embedded derivatives	1,200,000	$ 1,520,000	$ 1,520,000	$ 2,560,000
Discount	4,400,000
Effective interest rate during period		13.70%	13.50%
Term Loan \| Secured Debt \| Common Stock Warrants
Debt Instrument, Redemption [Line Items]
Warrant, fair value	$ 1,100,000
Term Loan \| Secured Debt \| Common Stock Warrants \| Common Stock
Debt Instrument, Redemption [Line Items]
Warrants (in shares)	730,769
Term Loan, First Tranche \| Secured Debt
Debt Instrument, Redemption [Line Items]
Borrowing capacity	$ 30,000,000
Term Loan, Second Tranche \| Secured Debt
Debt Instrument, Redemption [Line Items]
Borrowing capacity	20,000,000
Covenant, proceeds from issuance of debt required (at least)	$ 20,000,000

DEBT - Summary of Outstanding D

DEBT - Summary of Outstanding Debt (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023	Nov. 10, 2023
Debt Instrument, Redemption [Line Items]
Fair value of bifurcated embedded derivatives	$ 1,520	$ 2,560
Total debt, long-term	29,674	29,897
Term Loan \| Secured Debt
Debt Instrument, Redemption [Line Items]
Principal value of Term Loan, including Final Payment of $1,635	31,635	31,635
Fair value of bifurcated embedded derivatives	1,520	2,560	$ 1,200
Unamortized debt discount	(3,481)	(4,298)
Total debt, long-term	29,674	$ 29,897
Final payment fee	$ 1,635		$ 1,600

DEBT - Summary of Interest Expe

DEBT - Summary of Interest Expense, Debt (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Debt Instrument [Line Items]
Total interest expense related to debt	$ 1,027	$ 0	$ 3,031	$ 0
Term Loan \| Secured Debt
Debt Instrument [Line Items]
Interest expense based on the coupon interest rate of the outstanding debt	739		2,204
Accretion of debt discount	284		817
Total interest expense related to debt	$ 1,023		$ 3,021

DEBT - Summary of Aggregate Pri

DEBT - Summary of Aggregate Principal Payments (Details) - Term Loan - Secured Debt - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Debt Instrument [Line Items]
Year ended December 31, 2026	$ 10,104
Year ended December 31, 2027	21,531
Total principal payments due for Term Loan	$ 31,635	$ 31,635

STOCKHOLDERS_ EQUITY (Details)

STOCKHOLDERS’ EQUITY (Details)		9 Months Ended	27 Months Ended
STOCKHOLDERS’ EQUITY (Details)	Jul. 21, 2023 USD ($) $ / shares shares	Sep. 30, 2024 USD ($) votingRight $ / shares shares	Sep. 30, 2024 USD ($) votingRight $ / shares shares	Dec. 31, 2023 $ / shares shares	Nov. 10, 2023 $ / shares shares	Jul. 01, 2022 USD ($)
Class of Stock [Line Items]
Common stock and preferred stock, shares authorized (in shares)		310,000,000	310,000,000
Preferred stock, shares authorized (in shares)		10,000,000	10,000,000	10,000,000
Preferred stock, par value (in dollars per share) \| $ / shares		$ 0.0001	$ 0.0001	$ 0.0001
Common stock, shares authorized (in shares)		300,000,000	300,000,000	300,000,000
Common stock, par value (in dollars per share) \| $ / shares		$ 0.0001	$ 0.0001	$ 0.0001
Common stock, number of voting rights \| votingRight		1	1
Sale of stock, commission rate to sales agents						3%
Common Stock Warrants
Class of Stock [Line Items]
Exercise price (in dollars per share) \| $ / shares					$ 1.95
Class of warrants or rights term (in years)					10 years
Common Stock Warrants \| Common Stock
Class of Stock [Line Items]
Warrants (in shares)					730,769
2022 Registration Statement
Class of Stock [Line Items]
Sale of stock, maximum authorized amount \| $						$ 200,000,000
Offering
Class of Stock [Line Items]
Sale of stock, number of shares issued in transaction (in shares)	16,774,193
Sale of stock, price per share (in dollars per share) \| $ / shares	$ 7.75
Sale of stock, consideration received on transaction \| $	$ 121,900,000
At The Market Offering
Class of Stock [Line Items]
Sale of stock, maximum authorized amount \| $						$ 50,000,000
Sale of stock, number of shares issued in transaction (in shares)		2,068,246
Sale of stock, price per share (in dollars per share) \| $ / shares		$ 3.84	$ 3.84
Sale of stock, consideration received on transaction \| $		$ 7,900,000	$ 12,200,000

STOCK-BASED COMPENSATION - Addi

STOCK-BASED COMPENSATION - Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Jan. 01, 2024	Dec. 31, 2023
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options outstanding (in shares)	10,374,371			7,523,947
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average grant date fair value of options granted (in dollars per share)	$ 2.93	$ 4.53
Expected dividend yield	0%	0%
Option, cost not yet recognized, amount	$ 15.1
Weighted average period of recognition (in years)	2 years 6 months
Stock Options \| Granted after December 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	48 months
Cliff period (in years)	1 year
Contractual term (in years)	10 years
Stock Options \| Granted prior to December 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Contractual term (in years)	10 years
Stock Options \| Minimum \| Granted after December 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	12 months
Stock Options \| Minimum \| Granted prior to December 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	3 months
Stock Options \| Maximum \| Granted after December 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	48 months
Stock Options \| Maximum \| Granted prior to December 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	24 months
RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	3 years
Weighted average period of recognition (in years)	2 years 1 month 6 days
Non option, cost not yet recognized, amount	$ 4.6
RSUs \| Share-Based Payment Arrangement, Tranche One
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage	33.33%
RSUs \| Share-Based Payment Arrangement, Tranche Two
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage	33.33%
RSUs \| Share-Based Payment Arrangement, Tranche Three
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage	33.33%
Employee Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Outstanding stock maximum	1%
Common stock, capital shares reserved for future issuance (in shares)			579,105
Number of shares authorized (in shares)	1,769,088
Shares of common stock outstanding maximum (in shares)	800,000
Shares issued in period (in shares)	0
2021 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum threshold common stock issuable on exercise of incentive stock options (in shares)	12,000,000
Common stock, capital shares reserved for future issuance (in shares)			2,895,523
2021 Equity Incentive Plan \| Common Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Outstanding stock maximum	5%
Number of shares authorized (in shares)	14,668,721
Shares available for future grant (in shares)	2,535,928
2013 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options outstanding (in shares)	3,227,248

STOCK-BASED COMPENSATION - Summ

STOCK-BASED COMPENSATION - Summary of Share-Based Compensation Expense Related to Stock Options (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total stock-based compensation	$ 2,338	$ 1,600	$ 7,292	$ 4,511
General and administrative
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total stock-based compensation	1,436	1,127	4,678	3,143
Research and development
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total stock-based compensation	$ 902	$ 473	$ 2,614	$ 1,368

STOCK-BASED COMPENSATION - Su_2

STOCK-BASED COMPENSATION - Summary of Assumptions Used for Valuation of Fair Value of Stock (Details) - Stock Options	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Risk-free interest rate, minimum	3.81%	3.47%
Risk-free interest rate, maximum	5.10%	4.43%
Expected volatility, minimum	92%	90%
Expected volatility, maximum	103%	98%
Expected dividend yield	0%	0%
Minimum
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Expected term (in years)	10 months 24 days	5 years 6 months
Maximum
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Expected term (in years)	6 years 1 month 6 days	6 years 1 month 6 days

STOCK-BASED COMPENSATION - Su_3

STOCK-BASED COMPENSATION - Summary of Stock Option Activity (Details) $ / shares in Units, $ in Thousands	9 Months Ended
	Sep. 30, 2024 USD ($) $ / shares shares
Stock Options
Beginning balance (in shares) \| shares	7,523,947
Granted (in shares) \| shares	2,961,850
Forfeited (in shares) \| shares	(57,871)
Expired (in shares) \| shares	(53,555)
Ending balance (in shares) \| shares	10,374,371
Vested and exercisable (in shares) \| shares	5,664,870
Weighted Average Exercise Price
Beginning balance (in dollars per share) \| $ / shares	$ 4.01
Granted (in dollars per share) \| $ / shares	3.71
Forfeited (in dollars per share) \| $ / shares	7.36
Expired (in dollars per share) \| $ / shares	9.10
Ending balance (in dollars per share) \| $ / shares	3.88
Vested and exercisable (in dollars per share) \| $ / shares	$ 3.48
Weighted Average Remaining Contractual Life (in years)
Outstanding balance (in years)	7 years 8 months 12 days
Vested and exercisable (in years)	6 years 9 months 18 days
Aggregate Intrinsic Value (in thousands)
Ending balance, aggregate intrinsic value \| $	$ 4,461
Vested and exercisable, aggregate intrinsic value \| $	$ 4,186

STOCK-BASED COMPENSATION - Su_4

STOCK-BASED COMPENSATION - Summary of Restricted Stock Units Activity (Details) - RSUs	9 Months Ended
	Sep. 30, 2024 $ / shares shares
Number of Shares
Unvested beginning balance (in shares) \| shares	328,500
Granted (in shares) \| shares	1,204,640
Vested (in shares) \| shares	(109,493)
Forfeited (in shares) \| shares	(12,317)
Unvested ending balance (in shares) \| shares	1,411,330
Weighted Average Grant Date Fair Value
Unvested beginning balance (in dollars per share) \| $ / shares	$ 6.11
Granted (in dollars per share) \| $ / shares	4.15
Vested (in dollars per share) \| $ / shares	6.11
Forfeited (in dollars per share) \| $ / shares	4.59
Unvested ending balance (in dollars per share) \| $ / shares	$ 4.45

COMMITMENTS AND CONTINGENCIES (

COMMITMENTS AND CONTINGENCIES (Details) - License Agreements SFr in Millions	1 Months Ended
	Nov. 30, 2022 CHF (SFr)
Other Commitments [Line Items]
Payment of upfront fees	SFr 1
Royalty percentage	1%
Payment obligation, term (in years)	10 years

NET LOSS PER SHARE (Details)

NET LOSS PER SHARE (Details) - shares	9 Months Ended
NET LOSS PER SHARE (Details) - shares	Sep. 30, 2024	Sep. 30, 2023
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)	13,504,612	7,728,647
Shares issuable upon exercise of stock options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)	10,374,371	7,400,147
Shares issuable upon conversion election for Term Loan
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)	988,142	0
Shares issuable upon exercise of warrant
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)	730,769	0
Unvested RSUs
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)	1,411,330	328,500