Inhibrx Biosciences (INBX) 10-K 28 Feb 24 2023 FY Annual report Financial data

Cover

Cover - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Feb. 21, 2024	Jun. 30, 2023
Cover [Abstract]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2023
Current Fiscal Year End Date	--12-31
Document Transition Report	false
Entity File Number	001-39452
Entity Registrant Name	INHIBRX, INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	82-4257312
Entity Address, Address Line One	11025 N. Torrey Pines Road
Entity Address, Address Line Two	Suite 200
Entity Address, City or Town	La Jolla
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	92037
City Area Code	(858)
Local Phone Number	795-4220
Title of 12(b) Security	Common Stock, par value $0.0001
Trading Symbol	INBX
Security Exchange Name	NASDAQ
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	true
Document Financial Statement Error Correction	false
Entity Shell Company	false
Entity Public Float			$ 892.9
Entity Common Stock, Shares Outstanding (in shares)		47,392,447
Documents Incorporated by Reference	None.
Amendment Flag	false
Entity Central Index Key	0001739614
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	FY

Audit Information

Audit Information	12 Months Ended
	Dec. 31, 2023
Audit Information [Abstract]
Auditor Firm ID	243
Auditor Name	BDO USA, P.C.
Auditor Location	San Diego, California

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Current assets:
Cash and cash equivalents	$ 277,924	$ 273,865
Prepaid expenses and other current assets	16,656	6,371
Total current assets	295,358	280,493
Property and equipment, net	6,419	2,501
Operating right-of-use asset	2,952	4,717
Other non-current assets	3,164	3,164
Total assets	307,893	290,875
Current liabilities:
Accounts payable	10,954	8,326
Accrued expenses	43,295	17,224
Deferred revenue	0	166
Current portion of lease liability	2,063	1,860
Total current liabilities	56,312	27,576
Long-term debt, including final payment fee	206,968	202,069
Non-current portion of lease liability	1,110	3,173
Total liabilities	264,390	232,818
Commitments and contingencies (Note 9)
Stockholders’ equity:
Preferred stock, $0.0001 par value, 15,000,000 shares authorized and no shares outstanding as of December 31, 2023 and December 31, 2022	0	0
Common stock, $0.0001 par value, 120,000,000 shares authorized as of December 31, 2023 and December 31, 2022; 47,369,511 and 43,564,283 shares issued and outstanding as of December 31, 2023 and December 31, 2022, respectively	5	4
Additional paid-in-capital	657,232	430,426
Accumulated deficit	(613,734)	(372,373)
Total stockholders’ equity	43,503	58,057
Total liabilities and stockholders’ equity	307,893	290,875
Nonrelated Party
Current assets:
Accounts receivable	778	243
Related Party
Current assets:
Accounts receivable	$ 0	$ 14

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2023	Dec. 31, 2022
Statement of Financial Position [Abstract]
Preferred stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Preferred stock, shares authorized (in shares)	15,000,000	15,000,000
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)	120,000,000	120,000,000
Common stock, shares issued (in shares)	47,369,511	43,564,283
Common stock, shares outstanding (in shares)	47,369,511	43,564,283

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Revenue:
Total revenue	$ 1,800	$ 2,192
Operating expenses:
Research and development	191,640	110,186
General and administrative	29,381	21,123
Total operating expenses	221,021	131,309
Loss from operations	(219,221)	(129,117)
Other income (expense):
Interest expense	(31,840)	(18,181)
Interest income	11,917	2,074
Other income (expense), net	(580)	1
Total other expense	(20,503)	(16,106)
Loss before provision for income taxes	(239,724)	(145,223)
Provision for income taxes	3	3
Loss from equity method investment	1,634	0
Net loss	$ (241,361)	$ (145,226)
Net loss per share, basic (in dollars per share)	$ (5.12)	$ (3.62)
Net loss per share, diluted (in dollars per share)	$ (5.12)	$ (3.62)
Weighted-average shares of common stock outstanding, basic (in shares)	47,130	40,108
Weighted-average shares of common stock outstanding, diluted (in shares)	47,130	40,108
License fee revenue
Revenue:
Total revenue	$ 1,800	$ 2,178
Grant revenue
Revenue:
Total revenue	$ 0	$ 14

Consolidated Statements of Stoc

Consolidated Statements of Stockholders’ Equity - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Accumulated Deficit
Beginning balance (in shares) at Dec. 31, 2021		38,991,000
Beginning balance at Dec. 31, 2021	$ 52,383	$ 4	$ 279,526	$ (227,147)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation expense	20,450		20,450
Issuance of shares upon exercise of stock options (in shares)		241,000
Issuance of shares upon exercise of stock options	2,757		2,757
Issuance of shares, net of issuance costs (in shares)		4,332,000
Issuance of shares, net of issuance costs	126,981		126,981
Issuance of warrants	712		712
Net loss	$ (145,226)			(145,226)
Ending balance (in shares) at Dec. 31, 2022	43,564,283	43,564,000
Ending balance at Dec. 31, 2022	$ 58,057	$ 4	430,426	(372,373)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation expense	$ 24,846		24,846
Issuance of shares upon exercise of stock options (in shares)	184,000	184,000
Issuance of shares upon exercise of stock options	$ 2,316		2,316
Issuance of common stock and pre-funded warrants in private placement, net of issuance costs (in shares)		3,621,000
Issuance of common stock and pre-funded warrants in private placement, net of issuance costs	199,645	$ 1	199,644
Net loss	$ (241,361)			(241,361)
Ending balance (in shares) at Dec. 31, 2023	47,369,511	47,369,000
Ending balance at Dec. 31, 2023	$ 43,503	$ 5	$ 657,232	$ (613,734)

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Cash flows from operating activities
Net loss	$ (241,361)	$ (145,226)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	1,191	1,225
Accretion of debt discount and non-cash interest expense	4,899	3,448
Stock-based compensation expense	24,846	20,450
Non-cash lease expense	1,765	1,621
Loss from equity method investment	1,634	0
Non-cash license revenue	(1,634)	0
Loss on disposal of fixed assets	3	19
Changes in operating assets and liabilities:
Accounts receivable	(535)	130
Receivables from related parties	14	491
Prepaid expenses and other current assets	(10,285)	612
Other non-current assets	0	(1,317)
Accounts payable	2,109	(705)
Accrued expenses	26,071	7,603
Operating lease liability	(1,860)	(1,674)
Deferred revenue, current portion	(166)	(1,868)
Deferred revenue, non-current portion	0	(110)
Net cash used in operating activities	(193,309)	(115,301)
Cash flows from investing activities
Purchase of fixed assets	(4,593)	(686)
Net cash used in investing activities	(4,593)	(686)
Cash flows from financing activities
Proceeds from issuance of common stock and pre-funded warrants in private placement	200,000	0
Issuance costs associated with issuance of common stock and pre-funded warrants in private placement	(355)	0
Proceeds from ATM offering	0	127,371
Costs associated with ATM offering	0	(390)
Proceeds from the issuance of debt	0	128,863
Payment of fees associated with debt	0	(50)
Proceeds from exercise of stock options	2,316	2,757
Net cash provided by financing activities	201,961	258,551
Net increase in cash	4,059	142,564
Cash and cash equivalents at beginning of period	273,865	131,301
Cash and cash equivalents at end of period	277,924	273,865
Supplemental disclosure of cash flow information
Cash paid for interest	26,717	13,090
Cash paid for income taxes	3	4
Supplemental schedule of non-cash investing and financing activities
Payable for purchase of fixed assets	519	0
Fair value of warrants issued to lender in conjunction with February 2022 Amendment (as defined in Note 3)	$ 0	$ 712

ORGANIZATION AND SUMMARY OF SIG

ORGANIZATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	12 Months Ended
	Dec. 31, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
ORGANIZATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	ORGANIZATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Organization Inhibrx, Inc., or the Company, or Inhibrx, is a clinical-stage biopharmaceutical company focused on developing a broad pipeline of novel biologic therapeutic candidates. The Company combines target biology with protein engineering, technologies, and research and development to design therapeutic candidates. The Company’s current pipeline is focused on oncology and orphan diseases. The Company is subject to risks and uncertainties common to early-stage companies in the biopharmaceutical industry, including, but not limited to, risks associated with preclinical studies, clinical trials and regulatory applications, development by competitors of new technological innovations, dependence on key personnel, protection of proprietary technology, compliance with government regulations and the ability to secure additional capital to fund operations. The Company’s therapeutic candidates currently under development will require significant additional research and development efforts, including clinical and preclinical testing and marketing approval prior to commercialization. These efforts require significant amounts of capital, adequate personnel and infrastructure and extensive compliance-reporting capabilities. Even if the Company’s development efforts are successful, it is uncertain when, if ever, the Company will realize significant revenue from product sales. Basis of Presentation The accompanying consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America, or GAAP, and applicable rules and regulations of the Securities and Exchange Commission, or the SEC, related to an annual report on the Form 10-K. Principles of Consolidation The consolidated financial statements include the accounts of the Company and its wholly-owned subsidiary and have been prepared in conformity with GAAP. All intercompany accounts and transactions have been eliminated in consolidation. Liquidity As of December 31, 2023, the Company had an accumulated deficit of $613.7 million and cash and cash equivalents of $277.9 million. From its inception and through December 31, 2023, the Company has devoted substantially all of its efforts to therapeutic drug discovery and development, conducting preclinical studies and clinical trials, enabling manufacturing activities in support of its therapeutic candidates, pre-commercialization activities, organizing and staffing the Company, establishing its intellectual property portfolio and raising capital to support and expand these activities. In August 2023, the Company received gross proceeds of $200.0 million before deducting $0.4 million of offering expenses payable by the Company in a private placement transaction, or the Private Placement, with certain institutional and other accredited investors, or Purchasers, in which the Company sold and issued 3,621,314 shares of the Company’s common stock and, with respect to certain Purchasers, pre-funded warrants to purchase 6,714,636 shares of the Company’s common stock. See Note 4 for further discussion of this equity offering. The Company believes that its existing cash and cash equivalents will be sufficient to fund the Company’s operations for at least 12 months from the date these consolidated financial statements are issued. The Company plans to finance its future cash needs through equity offerings, debt financings or other capital sources, including potential collaborations, licenses, strategic transactions and other similar arrangements. If the Company does raise additional capital through public or private equity or convertible debt offerings, the ownership interests of its existing stockholders will be diluted, and the terms of those securities may include liquidation or other preferences that adversely affect its stockholders’ rights. If the Company raises capital through additional debt financings, it may be subject to covenants limiting or restricting its ability to take specific actions, such as incurring additional debt or making certain capital expenditures. To the extent that the Company raises additional capital through strategic licensing, collaboration or other similar agreement, it may have to relinquish valuable rights to its therapeutic candidates, future revenue streams or research programs at an earlier stage of development or on less favorable terms than it would otherwise choose, or to grant licenses on terms that may not be favorable to the Company. There can be no assurance as to the availability or terms upon which such financing and capital might be available in the future. If the Company is unable to secure adequate additional funding, it will need to reevaluate its operating plan and may be forced to make reductions in spending, extend payment terms with suppliers, liquidate assets where possible, delay, scale back or eliminate some or all of its development programs, or relinquish rights to its technology on less favorable terms than it would otherwise choose. These actions could materially impact its business, financial condition, results of operations and prospects. The rules and regulations of the SEC or any other regulatory agencies may restrict the Company’s ability to conduct certain types of financing activities, or may affect the timing of and amounts it can raise by undertaking such activities. Use of Estimates The preparation of these consolidated financial statements in conformity with GAAP requires the Company to make estimates and judgments that affect the reported amounts of assets, liabilities, revenue and expense and the disclosure of contingent assets and liabilities in the Company’s financial statements and accompanying notes. The Company’s most significant estimates relate to evaluation of whether revenue recognition criteria have been met, accounting for development work and preclinical studies and clinical trials, determining the assumptions used in measuring stock-based compensation, the incremental borrowing rate estimated in relation to the Company’s operating lease, and valuation allowances for the Company’s deferred tax assets. The Company bases its estimates on historical experience, known trends and other market-specific or other relevant factors that it believes to be reasonable under the circumstances. Estimates are periodically reviewed in light of changes in circumstances, facts and experience. Changes in estimates are recorded in the period in which they become known. The Company’s actual results may differ from these estimates under different assumptions or conditions. Fair Value of Financial Instruments The Company’s financial instruments consist principally of accounts receivable, investments in debt securities, accounts payable, accrued expense, long-term debt, and warrants. The carrying amounts of financial instruments such as accounts receivable, accounts payable, accrued expense, and investments in debt securities classified as cash equivalents approximate their related fair values due to the short-term nature of these instruments. The carrying value of the Company’s debt approximates fair value due to its interest being reflective of current market rates for debt with similar terms and conditions. The Company’s warrants are equity-classified and carried at the instruments’ fair value upon classification into equity. Cash and Cash Equivalents Cash and cash equivalents are comprised of cash held in financial institutions including readily available checking, overnight sweep and money market accounts, and highly liquid investments in debt securities with an original maturity of three months or less. The Company’s investments in debt securities have consisted of U.S. Treasury Bills, which were recorded at their amortized cost, reflective of the amortization or accretion of premiums or discounts. As of December 31, 2023, the Company held no investments in debt securities. As of December 31, 2022, these investments were recorded at their amortized cost of $196.3 million, which was adjusted for the amortization or accretion of premiums or discounts. Concentrations of Credit Risk Financial instruments that subject the Company to significant concentrations of credit risk consist primarily of cash and cash equivalents. The Company maintains deposits in federally insured financial institutions in excess of federally insured limits by the Federal Deposit Insurance Corporation, or FDIC, of up to $250,000. The Company’s cash management and investment policy limits investment instruments to investment-grade securities with the objective to preserve capital and to maintain liquidity until the funds can be used in operations. The Company has not experienced any losses in such accounts and believes it is not exposed to significant risk on its cash balances due to the financial condition of the depository institutions in which those deposits are held. The Company continually evaluates its accounts receivable for all outstanding third-party balances to determine the potential exposure to a concentration of credit risk. The Company’s major third-party contracting parties, some of which account for significant balances in both accounts receivable and revenue, are generally large, credit-worthy biotechnology companies and government bodies. The Company assesses the collectability of accounts receivable through a review of its current aging, as well as an analysis of its historical collection rate, general economic conditions, and credit status of these third parties. As of December 31, 2023 and December 31, 2022, all outstanding accounts receivable were deemed to be fully collectible, and therefore, no allowance for doubtful accounts was recorded. Dividends As of December 31, 2023, the Company has never declared or paid any dividends on its common stock. Additionally, the Amended 2020 Loan Agreement limits, among other things, the Company’s ability to pay dividends and make certain other payments. Any future determination to pay dividends on the Company’s common stock will be at the discretion of the Company’s board of directors and will depend upon, among other factors, the results of operations, financial condition, capital requirements, contract restrictions, business prospects and other factors the Company’s board of directors may deem relevant. Property and Equipment, Net Property and equipment are stated at cost less accumulated depreciation. Depreciation is provided on a straight-line basis over the estimated useful lives of the assets. The Company estimates useful lives as follows: • laboratory and office equipment: three • furniture, fixtures and other: five years; and • computer software: three years. Amortization of leasehold improvements is provided on a straight-line basis over the shorter of their estimated useful lives or the lease term. The costs of additions and betterments are capitalized, and repairs and maintenance costs are expensed in the periods incurred. Impairment of Long-Lived Assets The Company reviews long-lived assets for impairment whenever events or circumstances indicate that the carrying amount of an asset may not be recoverable. An impairment loss is recognized when estimated undiscounted future cash flows expected to result from the use of the asset and its eventual disposition are less than its carrying amount. If such assets are considered impaired, the amount of the impairment loss recognized is measured as the amount by which the carrying value of the asset exceeds the fair value of the asset, fair value being determined based upon future cash flows or appraised values, depending on the nature of the asset. The Company recognized no impairment losses during any of the periods presented within its consolidated financial statements. Leases The Company has two existing leases for its corporate headquarters in La Jolla, California. Its first lease commenced in June 2018. In May 2019, the Company signed an amendment to its lease agreement to expand the Company’s facilities, which commenced in January 2020 and is accounted for as a separate lease. The Company’s two existing leases are classified as operating leases. For the long-term operating lease of its corporate headquarters, the Company recognized an operating right-of-use asset and lease liability on its consolidated balance sheet. The lease liability is determined as the present value of future lease payments using an estimated incremental borrowing rate that the Company would have to pay to borrow equivalent funds on a collateralized basis at the lease commencement date. The operating right-of-use asset is based on the liability adjusted for any prepaid or deferred rent. The lease term at the commencement date is determined by considering whether renewal options and termination options are reasonably assured of exercise. Agreements are reviewed at inception to determine if they contain a lease. Leases are reviewed and classified as operating or financing leases at commencement. The Company has elected to exclude from its consolidated balance sheets recognition of leases having a term of 12 months or less (short-term leases) and has elected not to separate lease components and non-lease components for its long-term operating leases. Rent expense for the operating leases are recognized on a straight-line basis over the lease term and is included in operating expense in the consolidated statements of operations for all periods presented. Investment in Phylaxis The Company uses the equity method of accounting for equity investments in companies if the investment provides the ability to exercise significant influence, but not control, over operating and financial policies of the investee. As discussed in Note 6, the Company received an equity investment in the form of a 10% equity interest as consideration in a series of agreements with Phylaxis (as defined below), which was later increased to 15% in the fourth quarter of 2023 following the achievement of a milestone. This equity interest is accounted for as an equity method investment and the Company’s proportionate share of the net income or loss of Phylaxis is included as loss in equity method investment in the consolidated statement of operations. Judgment regarding the level of influence over each equity method investment includes considering key factors such as the Company’s ownership interest, representation on the board of directors, legal form of the investee (e.g. limited liability corporation), participation in policy-making decisions, and material purchase and sale transactions. The investment had been reduced to zero prior to the beginning of 2021 as a result of the allocation of the Company’s share of prior losses of the investee. Following the Company’s increase in equity interest of 5% in the fourth quarter of 2023, the Company established an additional equity method investment and subsequently recorded its proportionate loss as loss in equity method investment in the consolidated statement of operations. Accordingly, the Company’s investment in Phylaxis as of December 31, 2023 and December 31, 2022 is zero. Fair Value Measurements The Company determines the fair value measurements of applicable assets and liabilities based on a three-tier fair value hierarchy established by accounting guidance and prioritizes the inputs used in measuring fair value. These tiers include: • Level 1 - Quoted prices in active markets for identical assets or liabilities. • Level 2 - Inputs other than Level 1 that are observable, either directly or indirectly, such as quoted prices for similar assets or liabilities; quoted prices in markets that are not active; or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities. • Level 3 - Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities. In certain cases, the inputs used to measure fair value may fall into different levels of the fair value hierarchy. In such cases, the level in the fair value hierarchy within which the fair value measurement in its entirety falls has been determined based on the lowest level input that is significant to the fair value measurement in its entirety. The Company’s assessment of the significance of a particular input to the fair value measurement in its entirety requires judgment and considers factors specific to the asset or liability. During the years ended December 31, 2023 and December 31, 2022, the Company’s investments in debt securities consisted of U.S. Treasury Bills, which are classified as Level 1 in the fair value hierarchy. Due to the short-term nature of these securities which are classified as cash equivalents, the amortized value approximated fair value and the Company did not remeasure these instruments at fair value. As of December 31, 2023, the Company held no investments in debt securities. The Company’s outstanding debt is classified as Level 2 in the fair value hierarchy. As of December 31, 2023 and December 31, 2022, the Company had no financial instruments measured at fair value on a recurring basis. Deferred Financing Costs and Other Debt-Related Costs Deferred financing costs are capitalized, recorded as an offset to the Company’s debt balances and amortized as interest expense over the term of the associated debt instrument using the effective interest method, pursuant to ASC Topic 835-30, Imputation of Interest . If the maturity of the debt is accelerated as a result of default or early debt repayment, the amortization would then be accelerated. Amounts paid related to debt financing activities are presented on the consolidated balance sheet as a direct deduction from the debt liability. Deferred Offering Costs The Company capitalizes costs that are directly associated with equity financings until such financings are consummated at which time such costs are recorded against the gross proceeds of the offering. Legal, accounting, and filing fees related directly to the Company’s Shelf Registration are capitalized as deferred offering costs. Deferred offering costs associated with the Shelf Registration are reclassified to additional paid-in capital when the Company completes offerings under the Shelf Registration. In October 2022, the Company completed an offering under the Shelf Registration and offset $3.0 million of offering costs against the proceeds. In August 2023, the Company completed a private placement offering, under which the Company offset $0.4 million of offering costs against the proceeds. There were no deferred offering costs as of December 31, 2023 or December 31, 2022. Financial Instruments with Characteristics of Both Liabilities and Equity The Company accounts for issued warrants either as a liability or equity in accordance with ASC 480-10, Accounting for Certain Financial Instruments with Characteristics of both Liabilities and Equity, or ASC 480-10, and ASC 815-40, Accounting for Derivative Financial Instruments Indexed to, and Potentially Settled in, a Company’s Own Stock , or ASC 815-40. Under ASC 480-10, warrants are considered a liability if they are mandatorily redeemable and they require settlement in cash, other assets, or a variable number of shares. If warrants do not meet liability classification under ASC 480-10, the Company considers the requirements of ASC 815-40 to determine whether the warrants should be classified as a liability or as equity. Under ASC 815-40, contracts that may require settlement for cash are liabilities, regardless of the probability of the occurrence of the triggering event. Liability-classified warrants are measured at fair value on the issuance date and at the end of each reporting period. Any change in the fair value of the warrants after the issuance date is recorded in other expense, net in the consolidated statements of operations as a gain or loss. If warrants do not require liability classification under ASC 815-40, in order to conclude warrants should be classified as equity, the Company assesses whether the warrants are indexed to its common stock and whether the warrants are classified as equity under ASC 815-40 or under another applicable GAAP standard. Equity-classified warrants are accounted for at fair value on the issuance date with no changes in fair value recognized after the issuance date. The Company’s outstanding warrants do not meet the requirements for liability classification under ASC-480-10 or ASC-815-40. Therefore, the Company’s outstanding warrants are classified as equity as of and for the years ended December 31, 2023 and December 31, 2022. Revenue Recognition The Company has generated revenue from its license and collaboration agreements with partners, as well as from grants from government agencies and private not-for-profit organizations. Collaborative Research, Development, and License Agreements The Company enters into collaborative agreements with partners which may include the transfer of licenses, options to license, and the performance of research and development activities. The terms associated with these agreements may include one or more of the following (1) license fees; (2) nonrefundable up-front fees; (3) payments for reimbursement of research costs; (4) payments associated with achieving specific development, regulatory, or commercial milestones; and (5) royalties based on specified percentages of net product sales, if any. Payments received from customers are included in deferred revenue, allocated between current and non-current on the consolidated balance sheet, until all revenue recognition criteria are met. Typically, license fees, non-refundable upfront fees, and funding of research activities are considered fixed, while milestone payments, including option exercise fees, are identified as variable consideration, which is constrained and excluded from the transaction price. The Company will recognize revenue for sales-based royalty if and when a subsequent sale occurs. The Company applies significant judgment when making estimates and assumptions under these agreements, including evaluating whether contractual obligations represent distinct performance obligations, including the assessment of whether options represent material rights, determining whether there are observable standalone prices and allocating transaction price to performance obligations within a contract, assessing whether any licenses are functional or symbolic, determining when performance obligations have been met, and assessing the recognition of variable consideration. The Company evaluates each performance obligation to determine if it can be satisfied and recognized as revenue at a point in time or over time. Typically, performance obligations consisting of a transfer of a license or the achievement of milestones are recognized at a point in time upon the transfer, while performance obligations consisting of research activities are recognized over time using an input method which is representative of the Company’s efforts to fulfill the performance obligation, based on costs incurred with third-parties or internal labor hours performed. Grant Revenue The Company has been awarded a grant from the Congressionally Directed Medical Research Program, or CDMRP, funded through the DoD, under which the Company’s internal costs specifically covered by the grant for a specified project are subject to reimbursement when incurred. Since there is no transfer of control of goods or services to the granting agency, revenue is recognized as the Company incurs expenses related to the grant in the gross amount of the reimbursement and costs associated with these reimbursements are reflected as a component of research and development expense in the consolidated statements of operations. Accrued Research and Development and Clinical Trial Costs Research and development costs are expensed as incurred based on estimates of the period in which services and efforts are expended, and include the cost of compensation and related expenses, as well as expenses for third parties who conduct research and development on the Company’s behalf, pursuant to development and consulting agreements in place. The Company’s preclinical studies and clinical trials are performed internally, by third party contract research organizations, or CROs, and/or clinical investigators. The Company also engages with contract development and manufacturing organizations, or CDMOs, for clinical supplies and manufacturing scale-up activities related to its therapeutic candidates. Invoicing from these third parties may be monthly based upon services performed or based upon milestones achieved. The Company accrues these expenses based upon estimates determined by reviewing cost information provided by CROs and CDMOs, other third-party vendors and internal clinical personnel, and contractual arrangements with CROs and CDMOs and the scope of work to be performed. Costs incurred related to the Company’s purchases of in-process research and development for early-stage products or products that are not commercially viable and ready for use, or have no alternative future use, are charged to expense in the period incurred. Costs incurred related to the licensing of products that have not yet received marketing approval to be marketed, or that are not commercially viable and ready for use, or have no alternative future use, are charged to expense in the period incurred. Income Taxes Income taxes are accounted for under the asset and liability method. Deferred income taxes are recorded for temporary differences between financial statement carrying amounts and the tax basis of assets and liabilities. Deferred tax assets and liabilities reflect the tax rates expected to be in effect for the years in which the differences are expected to reverse. A valuation allowance is provided if it is more likely than not that some or all of the deferred tax assets will not be realized. The Company also follows the provisions of accounting for uncertainty in income taxes which prescribes a model for the recognition and measurement of a tax position taken or expected to be taken in a tax return, and provides guidance on derecognition, classification, interest and penalties, disclosure and transition. The utilization of unused federal and state net operating losses, or NOLs, and research tax credit carryforwards to offset future taxable income may be subject to an annual limitation as a result of ownership changes that have occurred previously or may occur in the future. Under Sections 382 and 383 of the Internal Revenue Code, as amended, or IRC, a corporation that undergoes an “ownership change” may be subject to limitations on its ability to utilize its pre-change NOLs and other tax attributes otherwise available to offset future taxable income and/or tax liability. An ownership change is defined as a cumulative change of 50% or more in the ownership positions of certain stockholders during a rolling three-year period. The Company is in the process of completing a formal study to determine if any ownership changes within the meaning of IRC Section 382 and 383 had occurred and, pending finalization, has not identified any ownership changes as of December 31, 2023. It is possible that the Company may incur ownership changes in the future. If an ownership change occurs, the Company’s ability to use its NOL or tax credit carryforwards may be restricted, which could require the Company to pay federal or state income taxes earlier than would be required if such limitations were not in effect. Net Loss Per Share Basic net loss per share is computed by dividing net loss by the weighted average number of common stock outstanding during the same period. Diluted net loss per share is computed by dividing net loss by the weighted average number of common and common stock equivalents outstanding during the same period. The Company excludes common stock equivalents from the calculation of diluted net loss per share when the effect is anti-dilutive. The weighted average number of common stock used in the basic and diluted net loss per common stock calculations includes the weighted-average pre-funded warrants outstanding during the period as they are exercisable at any time for nominal cash consideration. For purposes of the diluted net loss per share calculation, other than pre-funded warrants as discussed above, warrants for purchase of common stock and stock options are considered to be potentially dilutive securities. Accordingly, for the years ended December 31, 2023 and December 31, 2022, there is no difference in the number of shares used to calculate basic and diluted shares outstanding. Potentially dilutive securities not included in the calculation of diluted net loss per share, because to do so would be anti-dilutive, as weighted based on the period outstanding during each year, are as follows (in thousands): YEAR ENDED DECEMBER 31, 2023 2022 Outstanding stock options 6,336 5,018 Warrant to purchase common stock 47 45 6,383 5,063 Fair Value of Stock-Based Awards The Company recognizes compensation costs related to stock options based on the estimated fair value of the awards on the date of grant. The Company estimates the grant date fair value, and the resulting stock-based compensation expense, using the Black-Scholes option pricing model. The grant date fair value of the stock-based awards is generally recognized on a straight-line basis over the requisite service period, which is generally the vesting period of the respective awards. The Company recognizes forfeitures as they occur. Other Comprehensive Income The Company has no material components of other comprehensive loss and accordingly, net loss is equal to comprehensive loss in all periods presented. Segment Information The Company operates under one segment which develops biologic therapeutic candidates. Operating segments are identified as components of an enterprise about which separate discrete financial information is available for evaluation by the chief operating decision-maker in making decisions regarding resource allocation and assessing performance. Recent Accounting Pronouncements From time to time, new accounting pronouncements are issued by the Financial Accounting Standards Board, or FASB, or other standard setting bodies. The Company believes that the impact of the recently issued accounting pronouncements that are not yet effective will not have a material impact on its consolidated financial condition or results of operations upon adoption. Adoption of New Accounting Pronouncements In June 2016, the FASB issued Accounting Standards Update, or ASU, 2016-13, Financial Instruments - Credit Losses: Measurement of Credit Losses on Financial Instruments (Topic 326), which intends to improve financial reporting by requiring earlier recognition of credit losses on certain financial assets, such as held-to-maturity debt securities. Subsequent to the issuance of ASU 2016-13, the FASB issued several additional ASUs to clarify implementation guidance, provide narrow-scope improvements and provide additional disclosure guidance. The Company adopted ASU 2016-13 as of January 1, 2023, which did not result in a material impact on its consolidated financial statements and related disclosures. Recently Issued but Not Yet Adopted Accounting Pronouncements In December 2023, the FASB issued ASU 2023-09, Improvements to Income Tax Disclosures , which requires more detailed income tax disclosures. The guidance requires entities to disclose disaggregated information about their effective tax rate reconciliation as well as expanded information on income taxes paid by jurisdiction. The disclosure requirements will be applied on a prospective basis, with the option to apply them retrospectively. The standard is effective for fiscal years beginning after December 15, 2024, with early adoption permitted. The Company is evaluating the disclosure requirements related to the new standard. In November 2023, the FASB issued ASU 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures, which is intended to improve reportable segment disclosure requirements, primarily through additional disclosures about significant segment expenses, including for single reportable segment entities. The standard is effective for fiscal years beginning after December 15, 2023, and interim periods within fiscal years beginning after December 15, 2024, with early adoption permitted. The amendments should be applied retrosp

OTHER FINANCIAL INFORMATION

OTHER FINANCIAL INFORMATION	12 Months Ended
	Dec. 31, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
OTHER FINANCIAL INFORMATION	OTHER FINANCIAL INFORMATION Prepaid Expense and Other Current Assets Prepaid expense and other current assets were comprised of the following (in thousands): AS OF DECEMBER 31, 2023 2022 Clinical drug substance and product manufacturing (1) $ 9,888 $ 1,171 Clinical trials (2) 5,409 4,294 Licenses 728 493 Outside research and development services (3) 265 232 Other 366 181 Prepaid expense and other current assets $ 16,656 $ 6,371 (1) Relates primarily to the Company’s usage of third-party CDMOs for clinical and development efforts. See “Accrued Research and Development Clinical Trial Costs” in Note 1 for further discussion of the components of research and development. (2) Relates primarily to the Company’s prepayments to third-party CROs for management of clinical trials and prepayments for drug supply to be used in combination with the Company’s therapeutics. See “Accrued Research and Development Clinical Trial Costs” in Note 1 for further discussion of the components of research and development. (3) Relates to the Company’s usage of third parties for other research and development efforts. See “Accrued Research and Development Clinical Trial Costs” in Note 1 for further discussion of the components of research and development. Property and Equipment, Net Property and equipment, net were comprised of the following (in thousands): AS OF DECEMBER 31, 2023 2022 Machinery and equipment $ 8,480 $ 7,023 Furniture, fixtures and other 540 524 Leasehold improvements 441 441 Computer software 53 53 Construction in process (1) 3,592 — Total property and equipment 13,106 8,041 Less: accumulated depreciation and amortization (6,687) (5,540) Property and equipment, net $ 6,419 $ 2,501 (1) As of December 31, 2023, consists of renovations to the Company’s office space and software not yet placed in service. Depreciation and amortization expense totaled $1.2 million for each of the years ended December 31, 2023 and December 31, 2022, and consisted of the following (in thousands): YEAR ENDED DECEMBER 31, 2023 2022 Research and development $ 992 $ 1,003 General and administrative 199 222 Total depreciation and amortization expense $ 1,191 $ 1,225 Accrued Expenses Accrued expenses were comprised of the following (in thousands): AS OF DECEMBER 31, 2023 2022 Clinical drug substance and product manufacturing (1) $ 22,805 $ 5,381 Clinical trials (2) 9,224 4,527 Compensation expense 6,506 3,374 Interest expense 2,348 2,124 Other outside research and development (3) 1,129 1,164 Professional fees 780 428 Other 503 226 Accrued expenses $ 43,295 $ 17,224 (1) Relates primarily to the Company’s usage of third-party CDMOs for clinical and development efforts. See Note 1 for further discussion of the components of research and development. (2) Relates primarily to the Company’s usage of third-party CROs for management of clinical trials. See Note 1 for further discussion of the components of research and development. (3) Relates to the Company’s usage of third parties for other research and development efforts. See “Accrued Research and Development Clinical Trial Costs” in Note 1 for further discussion of the components of research and development.

DEBT

DEBT	12 Months Ended
	Dec. 31, 2023
Debt Disclosure [Abstract]
DEBT	DEBT 2020 Loan Agreement In July 2020, the Company entered into a loan and security agreement, or the 2020 Loan Agreement, with Oxford Finance LLC, or Oxford, pursuant to which it received $10.0 million in gross proceeds, or Term A. The 2020 Loan Agreement was subsequently amended in November 2020, or the November 2020 Amendment, upon which a second tranche in an aggregate principal amount of $20.0 million was funded, or Term B, and in June 2021, or the June 2021 Amendment, upon which a third tranche in an aggregate principal amount of $40.0 million was funded, or Term C. In February 2022, the Company entered into an additional amendment, or the February 2022 Amendment, to the 2020 Loan Agreement, collectively, the Amended 2020 Loan Agreement, upon which the Company received gross proceeds of $40.0 million, or Term D. The February 2022 Amendment also provided for an increase in the interest rate and for three future tranches of debt to be funded upon the achievement of certain milestones. In June 2022, the Company received additional gross proceeds of $30.0 million, or Term E, following the initiation of part 4 of the Phase 1 clinical trial of INBRX-105, as well as an additional $30.0 million in gross proceeds, or Term F, following the receipt of positive topline data from the Phase 1 clinical trial of INBRX-101. In October 2022, the Company entered into an amendment to the Amended 2020 Loan Agreement, or the October 2022 Amendment. The October 2022 Amendment amended the milestone terms of the last remaining tranche, Term G, under the Amended 2020 Loan Agreement to provide for the funding of $30.0 million upon the announcement of the regulatory path for INBRX-101 rather than upon the initiation of a potentially registration-enabling clinical trial of INBRX-101. In October 2022, the Company met this milestone and drew the final tranche for additional gross proceeds of $30.0 million. The Company determined the November 2020, June 2021, February 2022, and October 2022 Amendments should be treated as modifications of the original 2020 Loan Agreement since the terms and resulting cash flows were not substantially changed upon each of the amendments. The Company will continue to amortize the existing debt discounts prior to modification through the Amended Maturity Date (as defined below). As of July 1, 2023, a LIBOR Transition Event, as defined in the Amended 2020 Loan Agreement, occurred, and pursuant to the Amended 2020 Loan Agreement, Oxford selected a LIBOR Replacement Rate, as defined in the Amended 2020 Loan Agreement, replacing the 30 day U.S. Dollar London InterBank Offered Rate with the 1-Month Chicago Mercantile Exchange term secured overnight financing rate, or 1-Month CME Term SOFR, causing an amendment to the interest rate of the Company’s outstanding loans. No other terms were changed. The Company has elected the optional expedient under ASC Topic 848-20 and therefore deemed the modification to not be substantial. As of December 31, 2023, the Company has $200.0 million in gross principal outstanding in term loans under the Amended 2020 Loan Agreement. The outstanding term loans will mature on January 1, 2027, or the Amended Maturity Date, and bear interest at a floating per annum rate equal to the greater of (1) 8.30% or (2) the sum of (i) the 1 Month CME Term SOFR on the last business day of the month that immediately precedes the month in which the interest will accrue, (ii) 0.10%, and (iii) 8.19%. Under the Amended 2020 Loan Agreement, the repayment schedule provides for interest-only payments through February 1, 2025, followed by 23 months of principal and interest payments. In the event of a qualifying financing event in which the Company raises at least $100.0 million in upfront licensing or partnership proceeds by February 2025, the interest-only period may be extended an additional 12 months through February 1, 2026, which would then be followed by 11 months of equal payments of principal plus interest, beginning on March 1, 2026. Upon the Amended Maturity Date, a final payment of 9.0% of the original principal amount will be due to Oxford. This final payment of $18.0 million is being accreted over the life of the Amended 2020 Loan Agreement using the effective interest method. The Company has the option to prepay the outstanding balance of the term loans in full prior to the Amended Maturity Date, subject to a prepayment fee ranging from 1.0% to 3.0%, depending upon the timing of the prepayment. The Company’s outstanding debt balance under the Amended 2020 Loan Agreement consisted of the following as of December 31, 2023 and December 31, 2022 (in thousands). AS OF DECEMBER 31, 2023 2022 Term A $ 10,900 $ 10,900 Term B 21,800 21,800 Term C 43,600 43,600 Term D 43,600 43,600 Term E 32,700 32,700 Term F 32,700 32,700 Term G 32,700 32,700 Less: debt discount (11,032) (15,931) Long-term debt, including debt discount and final payment fee $ 206,968 $ 202,069 As of December 31, 2023, and unless extended in accordance with the terms described above, the Company’s interest-only period will continue through February 2025, with principal payments beginning in March 2025. Future principal payments and final fee payments will be made as follows (in thousands): AS OF DECEMBER 31, 2023 2025 $ 86,956 2026 104,348 2027 26,696 Total future minimum payments 218,000 Less: unamortized debt discount (11,032) Total debt $ 206,968 The Company’s obligations under the Amended 2020 Loan Agreement are secured by a first priority security interest of substantially all of the Company’s assets with a positive lien on intellectual property. The Amended 2020 Loan Agreement includes customary events of default, including instances of a material adverse change in the Company’s operations, that may require prepayment of the outstanding term loans. Additionally, following the June 2021 Amendment, the Amended 2020 Loan Agreement requires the Company to maintain a minimum cash balance of $20.0 million. As of December 31, 2023, the Company is in compliance with all covenants under the Amended 2020 Loan Agreement and has not received any notification or indication from Oxford of an intent to declare the loan due prior to maturity. Concurrently with the February 2022 Amendment, the Company issued 40,000 warrants to Oxford to purchase shares of the Company’s common stock at an exercise price of $45.00. Upon issuance, the warrants were classified as equity and recorded at their fair value of $0.7 million. See Note 4 for further discussion of these warrants. Interest Expense

STOCKHOLDERS_ EQUITY

STOCKHOLDERS’ EQUITY	12 Months Ended
	Dec. 31, 2023
Equity [Abstract]
STOCKHOLDERS’ EQUITY	STOCKHOLDERS’ EQUITY Open Market Sale Agreement In September 2021, the Company entered into the Open Market Sale Agreement, or the Sales Agreement, with Jefferies LLC, or the Sales Agent, under which it may, from time to time, sell shares of its common stock having an aggregate offering price of up to $200.0 million through the Sales Agent, or the ATM Offering. Pursuant to the Sales Agreement, the Company paid the Sales Agent a commission for its services in acting as an agent in the sale of common stock in an amount equal to 3% of the gross sales price per share sold, which was amended to 2% of the total sales price per share sold during 2022. During the year ended December 31, 2022, the Company sold 4,332,354 shares pursuant to the Sales Agreement for net proceeds of $127.4 million, after deducting commissions of $2.6 million. In connection with the ATM Offerings during the year ended December 31, 2022, the Company incurred an additional $0.4 million of expenses which were offset against the proceeds of the offering. During the year ended December 31, 2023, the Company did not issue any shares under the Sales Agreement. Securities Purchase Agreement In August 2023, the Company entered into a Securities Purchase Agreement, as amended, or the Purchase Agreement, with the Purchasers, pursuant to which the Company sold and issued 3,621,314 shares of the Company’s common stock for $19.35 per share and, with respect to certain Purchasers, pre-funded warrants to purchase 6,714,636 shares of the Company’s common stock in the Private Placement. The purchase price of the pre-funded warrants was $19.3499 per pre-funded warrant, with an exercise price of $0.0001 per share. The Company received gross proceeds of $200.0 million from the Private Placement, before deducting $0.4 million of offering expenses payable by the Company. The pre-funded warrants are equity-classified and carried at the instruments’ fair value upon issuance. The pre-funded warrants are exercisable upon issuance pursuant to certain beneficial ownership limitations as defined in the Purchase Agreement and will expire when exercised in full. As of December 31, 2023, all pre-funded warrants are still outstanding. Warrants Issued in Connection with Amended 2020 Loan Agreement As of December 31, 2023, the following equity-classified warrants were outstanding, in addition to the pre-funded warrants discussed above: Expiration Date Shares of Common Stock Issuable Upon Exercise of Warrants Exercise Price per Share July 15, 2030 7,354 $ 17.00 February 18, 2032 40,000 $ 45.00 The Company’s warrants are equity-classified and carried at the instruments’ fair value upon classification into equity, with no subsequent remeasurements. Common Stock Reserved for Future Issuance Common stock reserved for future issuance as of December 31, 2023 and December 31, 2022 consist of the following (in thousands): AS OF DECEMBER 31, 2023 2022 Options to purchase common stock issued and outstanding 6,494 5,305 Shares available for future equity grants 533 162 Pre-funded warrants issued and outstanding 6,715 — Warrants issued and outstanding 47 47 Total common stock reserved for future issuance 13,789 5,514

EQUITY COMPENSATION PLAN

EQUITY COMPENSATION PLAN	12 Months Ended
	Dec. 31, 2023
Share-Based Payment Arrangement [Abstract]
EQUITY COMPENSATION PLAN	EQUITY COMPENSATION PLAN Stock Incentive Plan The Company’s share-based compensation plan, the Amended and Restated 2017 Employee, Director and Consultant Equity Incentive Plan, or the 2017 Plan, provides for the issuance of incentive stock options, restricted and unrestricted stock awards, and other stock-based awards. As of December 31, 2023, an aggregate of 7.8 million shares of common stock were authorized for issuance under the 2017 Plan, of which 0.5 million remain available for issuance. Stock Option Activity The Company recognizes compensation costs related to stock-based awards, including stock options, based on the estimated fair value of the awards on the date of grant. The Company grants options with an exercise price equal to the fair market value of the Company’s stock on the date of the option grant. The options are subject to four-year vesting with a one-year cliff and have a contractual term of 10 years. A summary of the Company’s stock option activity under its 2017 Plan for the year ended December 31, 2023 is as follows (in thousands, except for per share data and years): Number of Shares Weighted Average Exercise Price Weighted Average Remaining Contractual Term (In Years) Aggregate Intrinsic Value Outstanding as of December 31, 2022 5,305 $ 22.95 Granted 1,615 $ 22.98 Forfeited (242) $ 23.88 Exercised (184) $ 12.59 Outstanding as of December 31, 2023 6,494 $ 23.22 7.6 $ 96,548 Vested and exercisable as of December 31, 2023 3,322 $ 21.80 6.6 $ 54,101 The aggregate intrinsic value of stock options exercised during the years ended December 31, 2023 and December 31, 2022 was $2.1 million and $3.7 million, respectively. Aggregate intrinsic value of stock options exercised and outstanding is calculated using the fair value of common stock on the date of exercise and as of December 31, 2023, respectively. The total fair value of stock options vested during the years ended December 31, 2023 and December 31, 2022 was $24.9 million and $25.0 million, respectively. Stock-Based Compensation Expense Stock options are valued using the Black-Scholes Merton option pricing model on the date of grant. This option pricing model involves a number of estimates, including the expected lives of the stock options, the Company’s anticipated stock volatility, and interest rates. Stock-based compensation expense is recognized using the straight-line method over the vesting period. The weighted-average assumptions used by the Company to estimate the fair value of stock option grants using the Black-Scholes option pricing model, as well as the resulting weighted-average fair value for the years ended December 31, 2023 and December 31, 2022 were as follows. YEAR ENDED DECEMBER 31, 2023 2022 Risk-free interest rate 3.77 % 2.63 % Expected volatility 84.31 % 85.26 % Expected dividend yield — % — % Expected term 6.08 6.08 Weighted average fair value $ 16.88 $ 17.72 The Company determines the assumptions used in the option pricing model in the following manner: Risk-Free Interest Rate— For the determination of the risk-free interest rates, the Company utilizes the U.S. Treasury yield curve for instruments in effect at the time of measurement with a term commensurate with the expected term assumption. Expected Volatility— Due to the Company’s limited historical stock price volatility data indicative of the expected future volatility, the Company based its estimate of expected volatility on the estimated and expected volatilities of a guideline group of publicly traded companies. For these analyses, the Company selected companies with comparable characteristics including enterprise value, risk profiles, and with historical share price information sufficient to meet the expected life of the stock-based awards. The Company computes the historical volatility data using the daily closing prices for the selected companies’ shares during the equivalent period of the calculated expected term of its stock-based awards. The Company will continue to apply this process until a sufficient amount of historical information regarding the volatility of its own stock price becomes available, or until the volatility of the Company’s market-traded shares best represents its expected volatility. Expected Dividend— The expected dividend yield is assumed to be zero since the Company has never paid dividends and does not have current plans to pay any dividends on its common stock. Expected Term— The Company estimates the expected term of its stock options granted to employees and non-employee directors using the simplified method, whereby, the expected term equals the average of the vesting term and the original contractual term of the option. The Company utilizes this method since it does not have sufficient historical exercise data to provide a reasonable basis upon which to estimate the expected term. Fair Value—T he fair value of the Company’s common stock is determined based on its closing market price on the date of the grant. The Company’s board of directors intended all options granted to be exercisable at a price per share not less than the per share fair value of its common stock underlying those options on the grant date. Stock-based compensation expense for stock options consisted of the following (in thousands): YEAR ENDED DECEMBER 31, 2023 2022 Research and development $ 16,630 $ 14,513 General and administrative 8,216 5,937 Total stock-based compensation expense $ 24,846 $ 20,450

LICENSE AND GRANT REVENUES

LICENSE AND GRANT REVENUES	12 Months Ended
	Dec. 31, 2023
Collaborative Arrangement and Arrangement Other than Collaborative [Abstract]
LICENSE AND GRANT REVENUES	LICENSE AND GRANT REVENUES The following table summarizes the total revenue recorded in the Company’s consolidated statements of operations (in thousands): YEAR ENDED DECEMBER 31, 2023 2022 License fee revenue Phylaxis BioScience, LLC $ 1,634 $ 1,101 Chiesi Farmaceutici S.p.A. 166 877 2seventy bio, Inc. — 200 Total license fee revenue 1,800 2,178 Grant revenue Congressionally Directed Medical Research Program — 14 Total grant revenue — 14 Total revenue $ 1,800 $ 2,192 License and Collaboration Agreements Phylaxis Agreements In July 2020, the Company entered into a joint venture with Phylaxis BioScience, LLC, or Phylaxis. In connection with the joint venture, the Company entered into the following agreements: Contribution Agreement, License Agreement, Limited Liability Company Agreement, and Master Services Agreement, or collectively the Phylaxis Agreements, pursuant to which the Company licensed certain intellectual property and know-how to Phylaxis and agreed to provide services to develop certain compounds. The Company received $5.0 million in nonrefundable, upfront payments from Phylaxis under the Master Services Agreement, or the MSA. In addition, upon closing, the Company received a 10% equity interest in Phylaxis as consideration for the contribution of the license of the Company’s intellectual property and know-how. Pursuant to the terms of the Phylaxis Agreements, during the fourth quarter of 2023, the Company received an additional 5% equity interest in Phylaxis following the achievement of a milestone event. Under the License Agreement, the Company is also entitled to specified development and commercialization milestone payments of up to an aggregate of $225.0 million and $175.0 million, respectively. The Company is also entitled to share in a percentage of the profits of Phylaxis under the Limited Liability Company Agreement. The Company recognized the initial transaction price of $5.5 million, comprised of the $5.0 million in upfront payments and the fair value of the 10% equity interest of $0.5 million, over the period of performance of development services on the two compounds. During the third quarter of 2022, the Company fulfilled this performance obligation in full and recognized all remaining deferred revenue under this contract. During the fourth quarter of 2023, the Company transferred a second generation compound to Phylaxis, which was a milestone event under the agreements. Upon transfer, the Company received an additional 5% equity interest in Phylaxis, which has a fair value of $1.6 million. The Company recognized the fair value of the 5% equity interest as revenue and accounted for the investment under the equity method. In order to determine the fair value of the equity interest in Phylaxis upon this milestone, the Company utilized the investee’s independent valuations based on recent financings from third party investors at fair market value. During the years ended December 31, 2023 and December 31, 2022, the Company recognized $1.6 million and $1.1 million of revenue under the Phylaxis agreements. As of December 31, 2023 and December 31, 2022, the Company had no deferred revenue related to this agreement. Chiesi In May 2019, the Company entered into an Option Agreement, as amended by the First Amendment to Option Agreement, dated August 19, 2019, or the Chiesi Option Agreement, with Chiesi Farmaceutici S.p.A., or Chiesi, pursuant to which the Company granted to Chiesi an exclusive option to obtain an exclusive license to develop and commercialize INBRX-101 outside of the United States and Canada. Additionally, the Chiesi Option Agreement provided Chiesi with a right of negotiation for INBRX-101 development and commercialization rights in the United States and Canada in the event that the Company engages in discussions with any third parties for such rights during the term of the Chiesi Option Agreement. Under the terms of the Chiesi Option Agreement, the Company received a one-time, non-refundable option initiation payment of $10.0 million in August 2019. The Company identified one performance obligation as of the effective date of the Chiesi Option Agreement, which is to perform research and development services for Chiesi during the option period, which would continue (unless the Chiesi Option Agreement is terminated earlier by Chiesi or the Company) until 60 days following the last to occur of (i) the Company’s delivery to Chiesi of the trial phase data for the first Phase I Clinical Trial, (ii) the Company’s delivery to Chiesi of the finalized minutes from the definitive U.S. Food and Drug Administration, or FDA, scientific advice meeting conducted following completion of such Phase I Clinical Trial, and (iii) the Company’s delivery to Chiesi of the finalized minutes from the definitive parallel European Medicines Agency health technology assessment, or EMA-HTA, scientific advice meeting conducted following completion of such Phase I Clinical Trial. The Company determined that the option to grant a license in the future is not a material right. On July 24, 2023, the Company provided a copy of the European Medicines Agency, or EMA, scientific advice to Chiesi upon receipt, which fulfilled the necessary deliverables to Chiesi and triggered the start of its 60-day option period window. On September 18, 2023, the Company was notified that Chiesi declined to exercise its option, resulting in the expiration of the Chiesi Option Agreement (upon the lapse of the option period), and with the Company retaining global rights to develop and commercialize INBRX-101. The $10.0 million upfront payment was allocated to the single performance obligation. Revenue is recognized over time as services are performed during the option period, based on the Company’s effort to satisfy the performance obligation relative to the total expense estimated to be incurred during the option period. During the years ended December 31, 2023 and December 31, 2022, the Company recognized $0.1 million and $0.9 million in revenue related to this agreement, respectively. As of December 31, 2023, the Company has no deferred revenue related to this agreement. As of December 31, 2022, the Company had $0.1 million current deferred revenue related to this agreement. 2seventy bio, Inc. In June 2020, the Company entered into an Option and License Agreement with bluebird, pursuant to which the Company granted to bluebird exclusive worldwide rights to develop binders and cell therapy products containing single domain antibodies, or sdAbs, directed to specified targets, consisting of two initial programs and up to an additional 8 programs. The Company retains all rights to the specific sdAbs outside of the cell therapy field. In November 2021, this agreement, or the 2020 2seventy Agreement, was assigned to 2seventy bio, Inc., or 2seventy, in connection with bluebird’s internal restructuring and subsequent spin-out of 2seventy. In June 2020, the Company received a non-refundable upfront option fee of $0.2 million in connection with each of the two initial programs, or $0.4 million in aggregate, and is entitled to an upfront option fee for each additional program, on a program-by-program basis. In June 2022, 2seventy selected a third program and paid a non-refundable upfront option fee of $0.2 million in exchange for a development license. Under each of the three programs, the Company has granted an option in which 2seventy may acquire an exclusive license with respect to all binders and cell therapy products developed under this agreement, which entitles the Company to additional fees upon exercise of the option. In connection with each program for which 2seventy exercises its option, 2seventy will be required to pay the Company a one-time, non-refundable, non-creditable fee in the low-single-digit millions. The Company is also entitled to receive certain developmental milestone payments of up to an aggregate of $51.5 million per therapeutic, as well as percentage tiered royalties on future product sales with rates in the mid-single-digits. Due to the uncertainty in the achievement of the developmental milestones and future sales, the variable consideration associated with the future milestone payments has been fully constrained (excluded) from the transaction price until such time that the Company concludes that it is probable that a significant reversal of previously recognized revenue will not occur. These estimates will be re-assessed at each reporting period. As of December 31, 2023, 2seventy has exercised one of its options and declined one of its options as related to the two initial programs, while the third program option remains outstanding. As of the effective date of the 2020 2seventy Agreement, the Company identified one performance obligation, which was the transfer of the exclusive development license to bluebird for the two initial programs. The Company determined that the option granted for an exclusive license in the future was not a material right. For the eight programs not identified upon execution of the contract, the Company evaluated the customer option for additional purchases and determined that those options for additional programs did not constitute material rights nor variable consideration. As additional programs are identified, the Company re-assesses its performance obligations and transaction price accordingly. In June 2022, pursuant to the terms regarding the addition of new programs in the 2020 2seventy Agreement, the Company received a $0.2 million upfront option fee related to the selection of a third program and transferred the related know-how and development license. The Company recognized the $0.2 million of revenue at the point in time in which the program was added and the program term began. During the year ended December 31, 2022, the Company recognized $0.2 million of revenue related to this agreement. The Company did not recognize any revenue related to this agreement during the year ended December 31, 2023. Government Grants Grant revenue was recognized in accordance with the Company’s stated methodology discussed in Note 1. CDMRP funded through the DoD In February 2021, the Company was awarded a grant from the DoD in the amount of approximately $0.3 million for the development of sdAb based therapeutics targeting SARS-CoV-2 Spike protein for the treatment of COVID-19, or the 2021 DoD grant. Work under the grant began in February 2021 and continued through February 2022. Revenue from this grant is based upon internal and subcontractor costs incurred by the Company that are specifically covered by the grants, and where applicable, an additional facilities and administrative rate that provided funding for overhead expenses. Revenue is recognized when the Company incurs these covered expenses related to the grant’s continued progression. The Company submits requests for reimbursement to the DoD for only those expenses which have been incurred by the Company in each period, resulting in reimbursement in arrears. During the year ended December 31, 2022, $14,000 was recognized as revenue under the grant. All work was completed during the year ended December 31, 2022. No revenue was recognized under the grant during the year ended December 31, 2023.

INCOME TAXES

INCOME TAXES	12 Months Ended
	Dec. 31, 2023
Income Tax Disclosure [Abstract]
INCOME TAXES	INCOME TAXES The components of income tax expense (benefit) were as follows for the years ended December 31, 2023 and December 31, 2022, respectively (in thousands): YEAR ENDED DECEMBER 31, 2023 2022 Current expense: State $ 3 $ 3 Total current expense $ 3 $ 3 The provision for the years ended December 31, 2023 and December 31, 2022 was related to state income taxes. A reconciliation of income tax expense to the amount computed by applying the statutory federal income tax rate to the loss from operations is summarized for the years ended December 31, 2023 and December 31, 2022 as follows (in thousands): YEAR ENDED DECEMBER 31, 2023 2022 Expected income tax benefit at federal statutory rate $ (50,684) $ (30,497) State income tax expense (benefit), net of federal benefit (3,568) (2,495) Permanent items 1,524 583 R&D credits (2,322) (1,261) Unrecognized tax benefits (FIN 48) 1,054 751 Return to provision true-ups (420) (135) Valuation allowance 54,419 33,057 Income tax expense $ 3 $ 3 Income taxes are accounted for under the asset and liability method. Deferred income taxes are recorded for temporary differences between financial statement carrying amounts and the tax basis of assets and liabilities. Deferred tax assets and liabilities reflect the tax rates expected to be in effect for the years in which the differences are expected to reverse. A valuation allowance is provided if it is more likely than not that some or all of the deferred tax assets will not be realized. The components of net deferred income taxes were as follows (in thousands): AS OF DECEMBER 31, 2023 2022 Deferred income tax assets Net operating loss carryforward $ 68,254 $ 52,970 Research and development credits 12,648 9,728 Intangibles 3,289 3,684 Accruals 1,412 696 Stock compensation 8,581 5,130 Capitalized research and development costs 51,772 19,585 Deferred revenue — 37 Operating lease liabilities 697 1,118 Other 10 — Gross deferred tax assets 146,663 92,948 Less: Valuation allowance (146,005) (91,586) Total deferred tax assets 658 1,362 Deferred income tax liabilities Fixed assets (10) (35) Operating lease right-of-use assets (648) (1,048) Other — (279) Total deferred tax liabilities (658) (1,362) Net deferred tax assets (liabilities) $ — $ — As of December 31, 2023, the Company had unused federal and state NOL carryforwards of approximately $305.1 million and $65.3 million, respectively. The federal NOL carryforwards may be carried forward indefinitely but are only available to offset up to 80% of pre-NOL taxable income each year. The state NOL carryforwards will begin to expire in 2038, if not utilized. As of December 31, 2023, the Company also had federal and state research tax credit carryforwards of $12.4 million and $6.2 million, respectively. The federal research tax credit carryforwards begin to expire in 2038, while the state carryforwards have no expiration. The utilization of NOL and research tax credit carryforwards to offset future taxable income may be subject to an annual limitation as a result of ownership changes that have occurred previously or may occur in the future. Under Sections 382 and 383 of the IRC, a corporation that undergoes an “ownership change” may be subject to limitations on its ability to utilize its pre-change NOLs and other tax attributes otherwise available to offset future taxable income and/or tax liability. An ownership change is defined as a cumulative change of 50% or more in the ownership positions of certain stockholders during a rolling three-year period. The Company is in the process of completing a formal study to determine if any ownership changes within the meaning of IRC Section 382 and 383 had occurred and, pending the finalization of the study, has not identified any ownership changes as of December 31, 2023. It is possible that the Company may incur additional ownership changes in the future. If an ownership change has occurred, the Company’s ability to use its NOL or tax credit carryforwards may be restricted, which could require the Company to pay federal or state income taxes earlier than would be required if such limitations were not in effect. The Company has established a full valuation allowance against its deferred tax assets due to uncertainties that preclude it from determining that it is more likely than not that the Company will be able to generate sufficient taxable income to realize such assets. Management assesses the available positive and negative evidence to estimate if sufficient future taxable income will be generated to utilize the existing deferred tax assets. A significant piece of objective negative evidence evaluated was the cumulative loss incurred over the three-year period ended December 31, 2023. Such objective evidence limits the ability to consider other subjective evidence such as the Company’s projections for future growth. Based on this evaluation, as of December 31, 2023, a valuation allowance of $146.0 million has been recorded in order to measure only the portion of the deferred tax asset that more likely than not will be realized. The amount of the deferred tax asset considered realizable, however, could be adjusted if objective negative evidence in the form of cumulative losses is no longer present and additional weight may be given to subjective evidence, such as estimates of future taxable income during carryforward periods and the Company’s projections for growth. The Company recognizes liabilities for uncertain tax positions based on a two-step process. The first step is to evaluate the tax position for recognition by determining if the weight of available evidence indicates that it is more likely than not that the position will be sustained on audit, including resolution of related appeals or litigation processes, if any. The second step is to measure the tax benefit as the largest amount that is more than 50% likely of being realized upon settlement. While the Company believes that it has appropriate support for the positions taken on its tax returns, the Company regularly assesses the potential outcome of examinations by tax authorities in determining the adequacy of its provision for income taxes. The following table summarizes the activity related to the Company’s unrecognized tax benefits (in thousands): AS OF DECEMBER 31, 2023 2022 Beginning balance $ 3,597 $ 2,846 Increases related to current year tax positions 1,054 751 Ending balance $ 4,651 $ 3,597 As of December 31, 2023, the Company had gross unrecognized tax benefits of $4.7 million, none of which would affect the effective tax rate due to the existence of a full valuation allowance. The Company does not expect any significant increases or decreases to its unrecognized tax benefits within the next 12 months. The Company’s policy is to recognize the interest expense and/or penalties related to income tax matters as a component of income tax expense. The Company had no accrual for interest or penalties on its consolidated balance sheets as of December 31, 2023 or December 31, 2022, and has not recognized interest and/or penalties in its consolidated statements of operations for the years ended December 31, 2023 and December 31, 2022 as the unrecognized tax benefits relate to tax positions for which no cash tax liability has been reduced.

LEASES

LEASES	12 Months Ended
	Dec. 31, 2023
Leases [Abstract]
LEASES	LEASES Operating Leases In September 2017, the Company entered into a seven-year lease agreement as its sole location in La Jolla, California. The lease expires in June 2025 with an option to extend the lease an additional five years, which is not included in the right-of-use asset and lease liabilities. The lease contained an initial base rent of approximately $0.1 million per month with 2% annual escalations, plus a percentage of taxes and operating expenses incurred by the lessor in connection with the ownership and management of the property, the latter of which to be determined annually. In May 2019, the Company executed an amendment to its lease agreement to expand its facilities and began occupying this space in January 2020. The amended lease terminates coterminously with the initial lease agreement and contains an initial base rent of approximately $30,000 per month with 2% annual escalations, plus a percentage of taxes and operating expenses incurred by the lessor in connection with the ownership and management of the property, the latter of which is to be determined annually. The operating right-of-use asset and operating lease liability as of December 31, 2023 and December 31, 2022 are as follows (in thousands): AS OF DECEMBER 31, 2023 2022 Operating right-of-use asset $ 2,952 $ 4,717 Operating lease liability Current 2,063 1,860 Non-current 1,110 3,173 Total operating lease liability $ 3,173 $ 5,033 During the years ended December 31, 2023 and December 31, 2022, the Company recognized operating lease expense of $3.7 million and $3.4 million, respectively. During each of the years ended December 31, 2023 and December 31, 2022, the Company paid $2.2 million for amounts included in the measurement of the operating lease liability in each period. As of December 31, 2023 and December 31, 2022, the Company’s operating lease had a remaining term of 1.5 and 2.5 years, respectively. The Company discounts its lease payments using its incremental borrowing rate as of the commencement of the lease. The Company has determined a weighted-average discount rate of 8.2% as of December 31, 2023 and December 31, 2022. Future minimum rental commitments for the Company’s operating leases reconciled to the operating lease liability are as follows (in thousands): AS OF DECEMBER 31, 2023 2024 $ 2,247 2025 1,137 Total future minimum lease payments $ 3,384 Less: imputed interest (211) Present value of operating lease liability 3,173 Less: current portion of operating lease liability (2,063) Non-current portion of operating lease liability $ 1,110

COMMITMENTS AND CONTINGENCIES

COMMITMENTS AND CONTINGENCIES	12 Months Ended
	Dec. 31, 2023
Commitments and Contingencies Disclosure [Abstract]
COMMITMENTS AND CONTINGENCIES	COMMITMENTS AND CONTINGENCIES Litigation Other than as described below, the Company is not party to any material legal proceedings. From time to time, it may be involved in legal proceedings or subject to claims incident to the ordinary course of business. Regardless of the outcome, such proceedings or claims can have an adverse impact on the Company because of defense and settlement costs, diversion of resources and other factors, and there can be no assurances that favorable outcomes will be obtained. I-Mab Litigation On March 1, 2022, I-Mab Biopharma, or I-Mab, filed a lawsuit against the Company and Brendan Eckelman, the Company’s co-founder and Chief Scientific Officer, in the United States District Court for the District of Delaware, C.A. No. 22-00276-CJB, asserting claims for misappropriation of trade secrets related to Dr. Eckelman’s service as an expert witness for Tracon Pharmaceuticals, Inc., or Tracon, in Tracon’s arbitration against I-Mab. The case is currently in the discovery process. Inhibrx is unable to reasonably estimate possible damages or a range of possible damages in this matter given the uncertainty and therefore has not recorded a liability on its books as of December 31, 2023. Indemnification In the ordinary course of business, the Company enters into agreements that may include indemnification provisions. Pursuant to such agreements, the Company may indemnify, hold harmless and defend an indemnified party for losses suffered or incurred by the indemnified party. In some cases, the indemnification obligation will continue after the termination of the agreement. The maximum potential amount of future payments the Company could be required to make under these provisions is not determinable. In addition, the Company has entered into indemnification agreements with its directors and certain officers that may require the Company, among other things, to indemnify them against certain liabilities that may arise by reason of their status or service as directors or officers. To date, no demands have been made upon the Company to provide indemnification under these agreements, and thus, there are no indemnification claims that the Company is aware of that could have a material effect on the Company’s consolidated balance sheets, consolidated statements of operations, or consolidated statements of cash flows. Purchase Commitments The Company has several ongoing contracts with CROs for preclinical studies and clinical trials and with CDMOs for clinical supplies and manufacturing scale-up activities. While these contracts are generally cancellable, some may contain specific activities that involve one or more noncancellable commitments, including minimum purchase commitments, binding annual forecasts, and capital equipment investments. Additionally, depending on the timing and reasoning of the exit, certain termination penalties may apply and can range from cost of work performed to date and up to twelve months of future committed manufacturing costs. As of December 31, 2023 and December 31, 2022, the noncancellable portion of these contracts total in aggregate, excluding amounts paid or incurred at each respective date, approximately $62.8 million and $74.8 million, respectively. The noncancellable purchase commitments as of December 31, 2023 relate to the purchase of raw materials and future contract manufacturing of drug supply for INBRX-101. During the years ended December 31, 2023 and December 31, 2022, the Company incurred $44.5 million and $0.3 million of expenses related to its non-cancellable purchase agreements, respectively. Other Commitments Additionally, as of December 31, 2023 and December 31, 2022, Mark P. Lappe, the Company’s Chief Executive Officer, Brendan P. Eckelman, the Company’s Chief Scientific Officer, and Kelly D. Deck, the Company’s Chief Financial Officer, and certain other members of management have agreements that provide for severance compensation in the event of termination or a change in control. Contingencies In connection with its proposed Merger (as defined below), the Company engaged legal counsel under a contingent fee arrangement. Under this agreement, the Company is obligated to pay a fee of $20.0 million, contingent upon the consummation of the proposed transaction. In the event the Merger is not completed, the Company does not owe any fees to its legal counsel. The Company will incur these costs in full upon the consummation of the Merger, if and when it is completed, and has not incurred any portion of this fee as of December 31, 2023.

SUBSEQUENT EVENTS

SUBSEQUENT EVENTS	12 Months Ended
	Dec. 31, 2023
Subsequent Events [Abstract]
SUBSEQUENT EVENTS	SUBSEQUENT EVENTS The Company evaluated subsequent events to assess the need for potential recognition or disclosure in this report. Based upon this evaluation, it was determined that no additional subsequent events required recognition or disclosure in these consolidated financial statements, other than disclosures related to those outlined below. Merger and Spin-Off On January 22, 2024, the Company, Aventis Inc., or Parent, a wholly owned indirect subsidiary of Sanofi, and Art Acquisition Sub, Inc., or the Merger Sub, a wholly owned subsidiary of Parent, entered into an Agreement and Plan of Merger, or the Merger Agreement. Pursuant to the terms of the Merger Agreement, Parent will acquire all outstanding shares of the Company via the merger of Merger Sub with and into the Company, or the Merger, with the Company surviving the Merger as a wholly owned subsidiary of Parent, and in turn each shareholder will receive (i) $30.00 per share in cash, (ii) one contingent value right per share, representing the right to receive a contingent payment of $5.00 in cash upon the achievement of a regulatory milestone, and (iii) one SEC-registered, publicly listed, share of Inhibrx Biosciences, Inc., or New Inhibrx, for every four shares of Inhibrx common stock held. In addition, in connection with the transaction, Parent will (1) assume and retire the Company’s outstanding third-party debt, (2) cause New Inhibrx to be funded with $200.0 million in cash, and (3) retain an equity interest in New Inhibrx of approximately 8%. In connection with and as a condition to the Merger, the Company and New Inhibrx entered into a Separation and Distribution Agreement, dated as of January 22, 2024, or the Separation and Distribution Agreement, pursuant to which, immediately prior to the effective time of the Merger: (i) the Company will effect a pre-closing reorganization, which will result in (x) the Company owning, assuming or retaining all assets and liabilities primarily related to INBRX-101, or the 101 Business, and (y) New Inhibrx owning, assuming or retaining all other assets and liabilities of the Company and its subsidiaries; and (ii) thereafter, the Company will distribute to its stockholders as of the record date on a pro rata basis, 92% of the issued and outstanding shares of New Inhibrx common stock, at a ratio of one share of New Inhibrx common stock for every four shares of the Company’s issued and outstanding common stock held on the record date. Following the spin-off, New Inhibrx will be a separate public company and the Company will retain 8% of the issued and outstanding shares of New Inhibrx common stock as of the effective time of the spin-off. The boards of directors of both the Company and Sanofi have unanimously approved the spin-off and the Merger. Parent will pay transaction consideration totaling approximately $2.2 billion in aggregate value. Parent will also make payments at the closing of the Merger to settle the Company’s third-party debt. Following the closing of the Merger, New Inhibrx will continue to operate under the Inhibrx name. Parent’s acquisition of the Company is subject to the completion of the New Inhibrx spin-off transaction and other customary closing conditions, including receipt of regulatory approvals and approval by the Company’s shareholders. The companies currently expect the transaction to close in the second quarter of 2024. The Merger Agreement contains certain termination rights for each of the Company and Parent. Upon termination of the Merger Agreement in accordance with its terms, under certain circumstances, the Company will be required to pay Parent a termination fee in an amount equal to $54.5 million, including if the Merger Agreement is terminated due to (i) the Company accepting a Superior Proposal (as defined in the Merger Agreement) or (ii) the Board changing its recommendation that stockholders vote to approve the Merger Agreement. This termination fee will also be payable by the Company if the Merger Agreement is terminated under certain circumstances and prior to such termination, a proposal to acquire the 101 Business or more than 50% of the Company’s stock or assets is made or publicly announced and not publicly withdrawn and the Company enters into a definitive agreement for, or completes, any transaction involving the acquisition of the 101 Business or more than 50% of its stock or assets within twelve months of such termination. The Merger Agreement also provides that Parent will be required to pay the Company a reverse termination fee of $92.1 million if the Merger is not consummated due to the failure of certain conditions to be satisfied as a result of failure to obtain antitrust clearance.

Pay vs Performance Disclosure

Pay vs Performance Disclosure - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Pay vs Performance Disclosure
Net loss	$ (241,361)	$ (145,226)

Insider Trading Arrangements

Insider Trading Arrangements	3 Months Ended
	Dec. 31, 2023
Trading Arrangements, by Individual
Rule 10b5-1 Arrangement Adopted	false
Non-Rule 10b5-1 Arrangement Adopted	false
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false

ORGANIZATION AND SUMMARY OF S_2

ORGANIZATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)	12 Months Ended
	Dec. 31, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	Basis of Presentation
Principles of Consolidation	Principles of Consolidation
Liquidity	Liquidity As of December 31, 2023, the Company had an accumulated deficit of $613.7 million and cash and cash equivalents of $277.9 million. From its inception and through December 31, 2023, the Company has devoted substantially all of its efforts to therapeutic drug discovery and development, conducting preclinical studies and clinical trials, enabling manufacturing activities in support of its therapeutic candidates, pre-commercialization activities, organizing and staffing the Company, establishing its intellectual property portfolio and raising capital to support and expand these activities. In August 2023, the Company received gross proceeds of $200.0 million before deducting $0.4 million of offering expenses payable by the Company in a private placement transaction, or the Private Placement, with certain institutional and other accredited investors, or Purchasers, in which the Company sold and issued 3,621,314 shares of the Company’s common stock and, with respect to certain Purchasers, pre-funded warrants to purchase 6,714,636 shares of the Company’s common stock. See Note 4 for further discussion of this equity offering. The Company believes that its existing cash and cash equivalents will be sufficient to fund the Company’s operations for at least 12 months from the date these consolidated financial statements are issued. The Company plans to finance its future cash needs through equity offerings, debt financings or other capital sources, including potential collaborations, licenses, strategic transactions and other similar arrangements. If the Company does raise additional capital through public or private equity or convertible debt offerings, the ownership interests of its existing stockholders will be diluted, and the terms of those securities may include liquidation or other preferences that adversely affect its stockholders’ rights. If the Company raises capital through additional debt financings, it may be subject to covenants limiting or restricting its ability to take specific actions, such as incurring additional debt or making certain capital expenditures. To the extent that the Company raises additional capital through strategic licensing, collaboration or other similar agreement, it may have to relinquish valuable rights to its therapeutic candidates, future revenue streams or research programs at an earlier stage of development or on less favorable terms than it would otherwise choose, or to grant licenses on terms that may not be favorable to the Company. There can be no assurance as to the availability or terms upon which such financing and capital might be available in the future. If the Company is unable to secure adequate additional funding, it will need to reevaluate its operating plan and may be forced to make reductions in spending, extend payment terms with suppliers, liquidate assets where possible, delay, scale back or eliminate some or all of its development programs, or relinquish rights to its technology on less favorable terms than it would otherwise choose. These actions could materially impact its business, financial condition, results of operations and prospects.
Use of Estimates	Use of Estimates The preparation of these consolidated financial statements in conformity with GAAP requires the Company to make estimates and judgments that affect the reported amounts of assets, liabilities, revenue and expense and the disclosure of contingent assets and liabilities in the Company’s financial statements and accompanying notes. The Company’s most significant estimates relate to evaluation of whether revenue recognition criteria have been met, accounting for development work and preclinical studies and clinical trials, determining the assumptions used in measuring stock-based compensation, the incremental borrowing rate estimated in relation to the Company’s operating lease, and valuation allowances for the Company’s deferred tax assets. The Company bases its estimates on historical experience, known trends and other market-specific or other relevant factors that it believes to be reasonable under the circumstances. Estimates are periodically reviewed in light of changes in circumstances, facts and experience. Changes in estimates are recorded in the period in which they become known. The Company’s actual results may differ from these estimates under different assumptions or conditions.
Fair Value of Financial Instruments	Fair Value of Financial Instruments The Company’s financial instruments consist principally of accounts receivable, investments in debt securities, accounts payable, accrued expense, long-term debt, and warrants. The carrying amounts of financial instruments such as accounts receivable, accounts payable, accrued expense, and investments in debt securities classified as cash equivalents approximate their related fair values due to the short-term nature of these instruments. The carrying value of the Company’s debt approximates fair value due to its interest being reflective of current market rates for debt with similar terms and conditions. The Company’s warrants are equity-classified and carried at the instruments’ fair value upon classification into equity.
Cash and Cash Equivalents	Cash and Cash Equivalents Cash and cash equivalents are comprised of cash held in financial institutions including readily available checking, overnight sweep and money market accounts, and highly liquid investments in debt securities with an original maturity of three months or less. The Company’s investments in debt securities have consisted of U.S. Treasury Bills, which were recorded at their amortized cost, reflective of the amortization or accretion of premiums or discounts.
Concentrations of Credit Risk	Concentrations of Credit Risk Financial instruments that subject the Company to significant concentrations of credit risk consist primarily of cash and cash equivalents. The Company maintains deposits in federally insured financial institutions in excess of federally insured limits by the Federal Deposit Insurance Corporation, or FDIC, of up to $250,000. The Company’s cash management and investment policy limits investment instruments to investment-grade securities with the objective to preserve capital and to maintain liquidity until the funds can be used in operations. The Company has not experienced any losses in such accounts and believes it is not exposed to significant risk on its cash balances due to the financial condition of the depository institutions in which those deposits are held.
Dividends	Dividends As of December 31, 2023, the Company has never declared or paid any dividends on its common stock.
Property and Equipment, Net	Property and Equipment, Net Property and equipment are stated at cost less accumulated depreciation. Depreciation is provided on a straight-line basis over the estimated useful lives of the assets. The Company estimates useful lives as follows: • laboratory and office equipment: three • furniture, fixtures and other: five years; and • computer software: three years.
Impairment of Long-Lived Assets	Impairment of Long-Lived Assets
Leases	Leases The Company has two existing leases for its corporate headquarters in La Jolla, California. Its first lease commenced in June 2018. In May 2019, the Company signed an amendment to its lease agreement to expand the Company’s facilities, which commenced in January 2020 and is accounted for as a separate lease. The Company’s two existing leases are classified as operating leases. For the long-term operating lease of its corporate headquarters, the Company recognized an operating right-of-use asset and lease liability on its consolidated balance sheet. The lease liability is determined as the present value of future lease payments using an estimated incremental borrowing rate that the Company would have to pay to borrow equivalent funds on a collateralized basis at the lease commencement date. The operating right-of-use asset is based on the liability adjusted for any prepaid or deferred rent. The lease term at the commencement date is determined by considering whether renewal options and termination options are reasonably assured of exercise. Agreements are reviewed at inception to determine if they contain a lease. Leases are reviewed and classified as operating or financing leases at commencement. The Company has elected to exclude from its consolidated balance sheets recognition of leases having a term of 12 months or less (short-term leases) and has elected not to separate lease components and non-lease components for its long-term operating leases.
Investment in Phylaxis	Investment in Phylaxis The Company uses the equity method of accounting for equity investments in companies if the investment provides the ability to exercise significant influence, but not control, over operating and financial policies of the investee. As discussed in Note 6, the Company received an equity investment in the form of a 10% equity interest as consideration in a series of agreements with Phylaxis (as defined below), which was later increased to 15% in the fourth quarter of 2023 following the achievement of a milestone. This equity interest is accounted for as an equity method investment and the Company’s proportionate share of the net income or loss of Phylaxis is included as loss in equity method investment in the consolidated statement of operations. Judgment regarding the level of influence over each equity method investment includes considering key factors such as the Company’s ownership interest, representation on the board of directors, legal form of the investee (e.g. limited liability corporation), participation in policy-making decisions, and material purchase and sale transactions.
Fair Value Measurements	Fair Value Measurements The Company determines the fair value measurements of applicable assets and liabilities based on a three-tier fair value hierarchy established by accounting guidance and prioritizes the inputs used in measuring fair value. These tiers include: • Level 1 - Quoted prices in active markets for identical assets or liabilities. • Level 2 - Inputs other than Level 1 that are observable, either directly or indirectly, such as quoted prices for similar assets or liabilities; quoted prices in markets that are not active; or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities. • Level 3 - Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities. In certain cases, the inputs used to measure fair value may fall into different levels of the fair value hierarchy. In such cases, the level in the fair value hierarchy within which the fair value measurement in its entirety falls has been determined based on the lowest level input that is significant to the fair value measurement in its entirety. The Company’s assessment of the significance of a particular input to the fair value measurement in its entirety requires judgment and considers factors specific to the asset or liability.
Deferred Financing Costs and Other Debt-Related Costs and Deferred Offering Costs	Deferred Financing Costs and Other Debt-Related Costs Deferred financing costs are capitalized, recorded as an offset to the Company’s debt balances and amortized as interest expense over the term of the associated debt instrument using the effective interest method, pursuant to ASC Topic 835-30, Imputation of Interest . If the maturity of the debt is accelerated as a result of default or early debt repayment, the amortization would then be accelerated. Amounts paid related to debt financing activities are presented on the consolidated balance sheet as a direct deduction from the debt liability. Deferred Offering Costs The Company capitalizes costs that are directly associated with equity financings until such financings are consummated at which time such costs are recorded against the gross proceeds of the offering.
Financial Instruments with Characteristics of Both Liabilities and Equity	Financial Instruments with Characteristics of Both Liabilities and Equity The Company accounts for issued warrants either as a liability or equity in accordance with ASC 480-10, Accounting for Certain Financial Instruments with Characteristics of both Liabilities and Equity, or ASC 480-10, and ASC 815-40, Accounting for Derivative Financial Instruments Indexed to, and Potentially Settled in, a Company’s Own Stock , or ASC 815-40. Under ASC 480-10, warrants are considered a liability if they are mandatorily redeemable and they require settlement in cash, other assets, or a variable number of shares. If warrants do not meet liability classification under ASC 480-10, the Company considers the requirements of ASC 815-40 to determine whether the warrants should be classified as a liability or as equity. Under ASC 815-40, contracts that may require settlement for cash are liabilities, regardless of the probability of the occurrence of the triggering event. Liability-classified warrants are measured at fair value on the issuance date and at the end of each reporting period. Any change in the fair value of the warrants after the issuance date is recorded in other expense, net in the consolidated statements of operations as a gain or loss. If warrants do not require liability classification under ASC 815-40, in order to conclude warrants should be classified as equity, the Company assesses whether the warrants are indexed to its common stock and whether the warrants are classified as equity under ASC 815-40 or under another applicable GAAP standard. Equity-classified warrants are accounted for at fair value on the issuance date with no changes in fair value recognized after the issuance date. The Company’s outstanding warrants do not meet the requirements for liability classification under ASC-480-10 or ASC-815-40. Therefore, the Company’s outstanding warrants are classified as equity as of and for the years ended December 31, 2023 and December 31, 2022.
Revenue Recognition	Revenue Recognition The Company has generated revenue from its license and collaboration agreements with partners, as well as from grants from government agencies and private not-for-profit organizations. Collaborative Research, Development, and License Agreements The Company enters into collaborative agreements with partners which may include the transfer of licenses, options to license, and the performance of research and development activities. The terms associated with these agreements may include one or more of the following (1) license fees; (2) nonrefundable up-front fees; (3) payments for reimbursement of research costs; (4) payments associated with achieving specific development, regulatory, or commercial milestones; and (5) royalties based on specified percentages of net product sales, if any. Payments received from customers are included in deferred revenue, allocated between current and non-current on the consolidated balance sheet, until all revenue recognition criteria are met. Typically, license fees, non-refundable upfront fees, and funding of research activities are considered fixed, while milestone payments, including option exercise fees, are identified as variable consideration, which is constrained and excluded from the transaction price. The Company will recognize revenue for sales-based royalty if and when a subsequent sale occurs. The Company applies significant judgment when making estimates and assumptions under these agreements, including evaluating whether contractual obligations represent distinct performance obligations, including the assessment of whether options represent material rights, determining whether there are observable standalone prices and allocating transaction price to performance obligations within a contract, assessing whether any licenses are functional or symbolic, determining when performance obligations have been met, and assessing the recognition of variable consideration. The Company evaluates each performance obligation to determine if it can be satisfied and recognized as revenue at a point in time or over time. Typically, performance obligations consisting of a transfer of a license or the achievement of milestones are recognized at a point in time upon the transfer, while performance obligations consisting of research activities are recognized over time using an input method which is representative of the Company’s efforts to fulfill the performance obligation, based on costs incurred with third-parties or internal labor hours performed. Grant Revenue The Company has been awarded a grant from the Congressionally Directed Medical Research Program, or CDMRP, funded through the DoD, under which the Company’s internal costs specifically covered by the grant for a specified project are subject to reimbursement when incurred. Since there is no transfer of control of goods or services to the granting agency, revenue is recognized as the Company incurs expenses related to the grant in the gross amount of the reimbursement and costs associated with these reimbursements are reflected as a component of research and development expense in the consolidated statements of operations.
Accrued Research and Development and Clinical Trial Costs	Accrued Research and Development and Clinical Trial Costs
Income Taxes	Income Taxes Income taxes are accounted for under the asset and liability method. Deferred income taxes are recorded for temporary differences between financial statement carrying amounts and the tax basis of assets and liabilities. Deferred tax assets and liabilities reflect the tax rates expected to be in effect for the years in which the differences are expected to reverse. A valuation allowance is provided if it is more likely than not that some or all of the deferred tax assets will not be realized. The Company also follows the provisions of accounting for uncertainty in income taxes which prescribes a model for the recognition and measurement of a tax position taken or expected to be taken in a tax return, and provides guidance on derecognition, classification, interest and penalties, disclosure and transition. The utilization of unused federal and state net operating losses, or NOLs, and research tax credit carryforwards to offset future taxable income may be subject to an annual limitation as a result of ownership changes that have occurred previously or may occur in the future. Under Sections 382 and 383 of the Internal Revenue Code, as
Net Loss Per Share	Net Loss Per Share Basic net loss per share is computed by dividing net loss by the weighted average number of common stock outstanding during the same period. Diluted net loss per share is computed by dividing net loss by the weighted average number of common and common stock equivalents outstanding during the same period. The Company excludes common stock equivalents from the calculation of diluted net loss per share when the effect is anti-dilutive. The weighted average number of common stock used in the basic and diluted net loss per common stock calculations includes the weighted-average pre-funded warrants outstanding during the period as they are exercisable at any time for nominal cash consideration. For purposes of the diluted net loss per share calculation, other than pre-funded warrants as discussed above, warrants for purchase of common stock and stock options are considered to be potentially dilutive securities. Accordingly, for the years ended December 31, 2023 and December 31, 2022, there is no difference in the number of shares used to calculate basic and diluted shares outstanding.
Fair Value of Stock-Based Awards	Fair Value of Stock-Based Awards
Other Comprehensive Income	Other Comprehensive Income
Segment Information	Segment Information
Recent Accounting Pronouncements	Recent Accounting Pronouncements From time to time, new accounting pronouncements are issued by the Financial Accounting Standards Board, or FASB, or other standard setting bodies. The Company believes that the impact of the recently issued accounting pronouncements that are not yet effective will not have a material impact on its consolidated financial condition or results of operations upon adoption. Adoption of New Accounting Pronouncements In June 2016, the FASB issued Accounting Standards Update, or ASU, 2016-13, Financial Instruments - Credit Losses: Measurement of Credit Losses on Financial Instruments (Topic 326), which intends to improve financial reporting by requiring earlier recognition of credit losses on certain financial assets, such as held-to-maturity debt securities. Subsequent to the issuance of ASU 2016-13, the FASB issued several additional ASUs to clarify implementation guidance, provide narrow-scope improvements and provide additional disclosure guidance. The Company adopted ASU 2016-13 as of January 1, 2023, which did not result in a material impact on its consolidated financial statements and related disclosures. Recently Issued but Not Yet Adopted Accounting Pronouncements In December 2023, the FASB issued ASU 2023-09, Improvements to Income Tax Disclosures , which requires more detailed income tax disclosures. The guidance requires entities to disclose disaggregated information about their effective tax rate reconciliation as well as expanded information on income taxes paid by jurisdiction. The disclosure requirements will be applied on a prospective basis, with the option to apply them retrospectively. The standard is effective for fiscal years beginning after December 15, 2024, with early adoption permitted. The Company is evaluating the disclosure requirements related to the new standard. In November 2023, the FASB issued ASU 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures, which is intended to improve reportable segment disclosure requirements, primarily through additional disclosures about significant segment expenses, including for single reportable segment entities. The standard is effective for fiscal years beginning after December 15, 2023, and interim periods within fiscal years beginning after December 15, 2024, with early adoption permitted. The amendments should be applied retrospectively to all prior periods presented in the financial statements. The Company is evaluating the disclosure requirements related to the new standard.

ORGANIZATION AND SUMMARY OF S_3

ORGANIZATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Tables)	12 Months Ended
	Dec. 31, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Schedule of Potential Dilutive Securities Excluded from Diluted Loss Per Share	Potentially dilutive securities not included in the calculation of diluted net loss per share, because to do so would be anti-dilutive, as weighted based on the period outstanding during each year, are as follows (in thousands): YEAR ENDED DECEMBER 31, 2023 2022 Outstanding stock options 6,336 5,018 Warrant to purchase common stock 47 45 6,383 5,063

OTHER FINANCIAL INFORMATION (Ta

OTHER FINANCIAL INFORMATION (Tables)	12 Months Ended
	Dec. 31, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Schedule of Prepaid Expense and Other Current Assets	Prepaid expense and other current assets were comprised of the following (in thousands): AS OF DECEMBER 31, 2023 2022 Clinical drug substance and product manufacturing (1) $ 9,888 $ 1,171 Clinical trials (2) 5,409 4,294 Licenses 728 493 Outside research and development services (3) 265 232 Other 366 181 Prepaid expense and other current assets $ 16,656 $ 6,371 (1) Relates primarily to the Company’s usage of third-party CDMOs for clinical and development efforts. See “Accrued Research and Development Clinical Trial Costs” in Note 1 for further discussion of the components of research and development. (2) Relates primarily to the Company’s prepayments to third-party CROs for management of clinical trials and prepayments for drug supply to be used in combination with the Company’s therapeutics. See “Accrued Research and Development Clinical Trial Costs” in Note 1 for further discussion of the components of research and development. (3) Relates to the Company’s usage of third parties for other research and development efforts. See “Accrued Research and Development Clinical Trial Costs” in Note 1 for further discussion of the components of research and development.
Schedule of Property and Equipment	Property and equipment, net were comprised of the following (in thousands): AS OF DECEMBER 31, 2023 2022 Machinery and equipment $ 8,480 $ 7,023 Furniture, fixtures and other 540 524 Leasehold improvements 441 441 Computer software 53 53 Construction in process (1) 3,592 — Total property and equipment 13,106 8,041 Less: accumulated depreciation and amortization (6,687) (5,540) Property and equipment, net $ 6,419 $ 2,501 (1) As of December 31, 2023, consists of renovations to the Company’s office space and software not yet placed in service. Depreciation and amortization expense totaled $1.2 million for each of the years ended December 31, 2023 and December 31, 2022, and consisted of the following (in thousands): YEAR ENDED DECEMBER 31, 2023 2022 Research and development $ 992 $ 1,003 General and administrative 199 222 Total depreciation and amortization expense $ 1,191 $ 1,225
Schedule of Accrued Expenses	Accrued Expenses Accrued expenses were comprised of the following (in thousands): AS OF DECEMBER 31, 2023 2022 Clinical drug substance and product manufacturing (1) $ 22,805 $ 5,381 Clinical trials (2) 9,224 4,527 Compensation expense 6,506 3,374 Interest expense 2,348 2,124 Other outside research and development (3) 1,129 1,164 Professional fees 780 428 Other 503 226 Accrued expenses $ 43,295 $ 17,224 (1) Relates primarily to the Company’s usage of third-party CDMOs for clinical and development efforts. See Note 1 for further discussion of the components of research and development. (2) Relates primarily to the Company’s usage of third-party CROs for management of clinical trials. See Note 1 for further discussion of the components of research and development. (3) Relates to the Company’s usage of third parties for other research and development efforts. See “Accrued Research and Development Clinical Trial Costs” in Note 1 for further discussion of the components of research and development.

DEBT (Tables)

DEBT (Tables)	12 Months Ended
	Dec. 31, 2023
Debt Disclosure [Abstract]
Schedule of Long-term Debt	The Company’s outstanding debt balance under the Amended 2020 Loan Agreement consisted of the following as of December 31, 2023 and December 31, 2022 (in thousands). AS OF DECEMBER 31, 2023 2022 Term A $ 10,900 $ 10,900 Term B 21,800 21,800 Term C 43,600 43,600 Term D 43,600 43,600 Term E 32,700 32,700 Term F 32,700 32,700 Term G 32,700 32,700 Less: debt discount (11,032) (15,931) Long-term debt, including debt discount and final payment fee $ 206,968 $ 202,069
Schedule of Maturities of Long-term Debt	Future principal payments and final fee payments will be made as follows (in thousands): AS OF DECEMBER 31, 2023 2025 $ 86,956 2026 104,348 2027 26,696 Total future minimum payments 218,000 Less: unamortized debt discount (11,032) Total debt $ 206,968

STOCKHOLDERS_ EQUITY (Tables)

STOCKHOLDERS’ EQUITY (Tables)	12 Months Ended
	Dec. 31, 2023
Equity [Abstract]
Schedule of Warrants Issued	As of December 31, 2023, the following equity-classified warrants were outstanding, in addition to the pre-funded warrants discussed above: Expiration Date Shares of Common Stock Issuable Upon Exercise of Warrants Exercise Price per Share July 15, 2030 7,354 $ 17.00 February 18, 2032 40,000 $ 45.00
Schedule of Common Stock Reserved For Future Issuance	Common stock reserved for future issuance as of December 31, 2023 and December 31, 2022 consist of the following (in thousands): AS OF DECEMBER 31, 2023 2022 Options to purchase common stock issued and outstanding 6,494 5,305 Shares available for future equity grants 533 162 Pre-funded warrants issued and outstanding 6,715 — Warrants issued and outstanding 47 47 Total common stock reserved for future issuance 13,789 5,514

EQUITY COMPENSATION PLAN (Table

EQUITY COMPENSATION PLAN (Tables)	12 Months Ended
	Dec. 31, 2023
Share-Based Payment Arrangement [Abstract]
Schedule of Stock Options Activity	A summary of the Company’s stock option activity under its 2017 Plan for the year ended December 31, 2023 is as follows (in thousands, except for per share data and years): Number of Shares Weighted Average Exercise Price Weighted Average Remaining Contractual Term (In Years) Aggregate Intrinsic Value Outstanding as of December 31, 2022 5,305 $ 22.95 Granted 1,615 $ 22.98 Forfeited (242) $ 23.88 Exercised (184) $ 12.59 Outstanding as of December 31, 2023 6,494 $ 23.22 7.6 $ 96,548 Vested and exercisable as of December 31, 2023 3,322 $ 21.80 6.6 $ 54,101
Schedule of Weighted-Average Assumptions Used to Estimate Fair Value	The weighted-average assumptions used by the Company to estimate the fair value of stock option grants using the Black-Scholes option pricing model, as well as the resulting weighted-average fair value for the years ended December 31, 2023 and December 31, 2022 were as follows. YEAR ENDED DECEMBER 31, 2023 2022 Risk-free interest rate 3.77 % 2.63 % Expected volatility 84.31 % 85.26 % Expected dividend yield — % — % Expected term 6.08 6.08 Weighted average fair value $ 16.88 $ 17.72
Schedule of Stock-Based Compensation Expense	Stock-based compensation expense for stock options consisted of the following (in thousands): YEAR ENDED DECEMBER 31, 2023 2022 Research and development $ 16,630 $ 14,513 General and administrative 8,216 5,937 Total stock-based compensation expense $ 24,846 $ 20,450

LICENSE AND GRANT REVENUES (Tab

LICENSE AND GRANT REVENUES (Tables)	12 Months Ended
	Dec. 31, 2023
Collaborative Arrangement and Arrangement Other than Collaborative [Abstract]
Schedule of License and Grant Revenue	The following table summarizes the total revenue recorded in the Company’s consolidated statements of operations (in thousands): YEAR ENDED DECEMBER 31, 2023 2022 License fee revenue Phylaxis BioScience, LLC $ 1,634 $ 1,101 Chiesi Farmaceutici S.p.A. 166 877 2seventy bio, Inc. — 200 Total license fee revenue 1,800 2,178 Grant revenue Congressionally Directed Medical Research Program — 14 Total grant revenue — 14 Total revenue $ 1,800 $ 2,192

INCOME TAXES (Tables)

INCOME TAXES (Tables)	12 Months Ended
	Dec. 31, 2023
Income Tax Disclosure [Abstract]
Schedule of Components of Income Tax Expense (Benefit)	The components of income tax expense (benefit) were as follows for the years ended December 31, 2023 and December 31, 2022, respectively (in thousands): YEAR ENDED DECEMBER 31, 2023 2022 Current expense: State $ 3 $ 3 Total current expense $ 3 $ 3
Schedule of Effective Income Tax Rate Reconciliation	A reconciliation of income tax expense to the amount computed by applying the statutory federal income tax rate to the loss from operations is summarized for the years ended December 31, 2023 and December 31, 2022 as follows (in thousands): YEAR ENDED DECEMBER 31, 2023 2022 Expected income tax benefit at federal statutory rate $ (50,684) $ (30,497) State income tax expense (benefit), net of federal benefit (3,568) (2,495) Permanent items 1,524 583 R&D credits (2,322) (1,261) Unrecognized tax benefits (FIN 48) 1,054 751 Return to provision true-ups (420) (135) Valuation allowance 54,419 33,057 Income tax expense $ 3 $ 3
Schedule of Deferred Tax Assets and Liabilities	The components of net deferred income taxes were as follows (in thousands): AS OF DECEMBER 31, 2023 2022 Deferred income tax assets Net operating loss carryforward $ 68,254 $ 52,970 Research and development credits 12,648 9,728 Intangibles 3,289 3,684 Accruals 1,412 696 Stock compensation 8,581 5,130 Capitalized research and development costs 51,772 19,585 Deferred revenue — 37 Operating lease liabilities 697 1,118 Other 10 — Gross deferred tax assets 146,663 92,948 Less: Valuation allowance (146,005) (91,586) Total deferred tax assets 658 1,362 Deferred income tax liabilities Fixed assets (10) (35) Operating lease right-of-use assets (648) (1,048) Other — (279) Total deferred tax liabilities (658) (1,362) Net deferred tax assets (liabilities) $ — $ —
Schedule of Unrecognized Tax Benefits Roll Forward	The following table summarizes the activity related to the Company’s unrecognized tax benefits (in thousands): AS OF DECEMBER 31, 2023 2022 Beginning balance $ 3,597 $ 2,846 Increases related to current year tax positions 1,054 751 Ending balance $ 4,651 $ 3,597

LEASES (Tables)

LEASES (Tables)	12 Months Ended
	Dec. 31, 2023
Leases [Abstract]
Schedule of Operating Lease, by Balance Sheet Location	The operating right-of-use asset and operating lease liability as of December 31, 2023 and December 31, 2022 are as follows (in thousands): AS OF DECEMBER 31, 2023 2022 Operating right-of-use asset $ 2,952 $ 4,717 Operating lease liability Current 2,063 1,860 Non-current 1,110 3,173 Total operating lease liability $ 3,173 $ 5,033
Schedule of Operating Lease Maturity	Future minimum rental commitments for the Company’s operating leases reconciled to the operating lease liability are as follows (in thousands): AS OF DECEMBER 31, 2023 2024 $ 2,247 2025 1,137 Total future minimum lease payments $ 3,384 Less: imputed interest (211) Present value of operating lease liability 3,173 Less: current portion of operating lease liability (2,063) Non-current portion of operating lease liability $ 1,110

ORGANIZATION AND SUMMARY OF S_4

ORGANIZATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Narrative (Details)	1 Months Ended	3 Months Ended	12 Months Ended
	Aug. 31, 2023 USD ($) shares	Dec. 31, 2023 USD ($) lease	Dec. 31, 2023 USD ($) segment lease	Dec. 31, 2022 USD ($)	Oct. 31, 2022 USD ($)	Dec. 31, 2020 USD ($)	Jul. 31, 2020 USD ($)
Property, Plant and Equipment [Line Items]
Accumulated deficit		$ 613,734,000	$ 613,734,000	$ 372,373,000
Cash and cash equivalents		277,924,000	277,924,000	273,865,000
Proceeds from issuance of common stock and pre-funded warrants in private placement			355,000	0
Debt securities, amortized cost		$ 0	$ 0	196,300,000
Number of operating leases held | lease		2	2
Deferred offering costs		$ 0	$ 0	0	$ 3,000,000
Number of operating segments | segment			1
Phylaxis BioScience, LLC
Property, Plant and Equipment [Line Items]
Equity interest percentage (as a percent)		15%	15%				10%
Equity method investment		$ 0	$ 0	$ 0		$ 0	$ 500,000
Equity method investment, ownership percentage, increase during period (as a percent)		5%
Furniture, fixtures and other
Property, Plant and Equipment [Line Items]
Property and equipment useful life (in years)		5 years	5 years
Computer software
Property, Plant and Equipment [Line Items]
Property and equipment useful life (in years)		3 years	3 years
Minimum | Machinery and equipment
Property, Plant and Equipment [Line Items]
Property and equipment useful life (in years)		3 years	3 years
Maximum | Machinery and equipment
Property, Plant and Equipment [Line Items]
Property and equipment useful life (in years)		5 years	5 years
Private Placement
Property, Plant and Equipment [Line Items]
Sale of stock, proceeds received	$ 200,000,000
Proceeds from issuance of common stock and pre-funded warrants in private placement	$ 400,000
Sale of stock, shares issued/sold (in shares) | shares	3,621,314
Private Placement | Warrants, Pre-Funded
Property, Plant and Equipment [Line Items]
Shares of common stock issuable upon exercise of warrants (in shares) | shares	6,714,636

ORGANIZATION AND SUMMARY OF S_5

ORGANIZATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Potential Dilutive Securities (Details) - shares shares in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Antidilutive securities excluded from earnings per share computation (in shares)	6,383	5,063
Outstanding stock options
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Antidilutive securities excluded from earnings per share computation (in shares)	6,336	5,018
Warrant to purchase common stock
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Antidilutive securities excluded from earnings per share computation (in shares)	47	45

OTHER FINANCIAL INFORMATION - P

OTHER FINANCIAL INFORMATION - Prepaid Expense and Other Current Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Clinical drug substance and product manufacturing	$ 9,888	$ 1,171
Clinical trials	5,409	4,294
Licenses	728	493
Outside research and development services	265	232
Other	366	181
Prepaid expense and other current assets	$ 16,656	$ 6,371

OTHER FINANCIAL INFORMATION -_2

OTHER FINANCIAL INFORMATION - Property and Equipment (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 13,106	$ 8,041
Less: accumulated depreciation and amortization	(6,687)	(5,540)
Property and equipment, net	6,419	2,501
Machinery and equipment
Property, Plant and Equipment [Line Items]
Total property and equipment	8,480	7,023
Furniture, fixtures and other
Property, Plant and Equipment [Line Items]
Total property and equipment	540	524
Leasehold improvements
Property, Plant and Equipment [Line Items]
Total property and equipment	441	441
Computer software
Property, Plant and Equipment [Line Items]
Total property and equipment	53	53
Construction in process
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 3,592	$ 0

OTHER FINANCIAL INFORMATION - D

OTHER FINANCIAL INFORMATION - Depreciation and Amortization Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Property, Plant and Equipment [Line Items]
Depreciation and amortization	$ 1,191	$ 1,225
Research and development
Property, Plant and Equipment [Line Items]
Depreciation and amortization	992	1,003
General and administrative
Property, Plant and Equipment [Line Items]
Depreciation and amortization	$ 199	$ 222

OTHER FINANCIAL INFORMATION - A

OTHER FINANCIAL INFORMATION - Accrued Expenses (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Clinical drug substance and product manufacturing	$ 22,805	$ 5,381
Clinical trials	9,224	4,527
Compensation expense	6,506	3,374
Interest expense	2,348	2,124
Other outside research and development	1,129	1,164
Professional fees	780	428
Other	503	226
Accrued expenses	$ 43,295	$ 17,224

DEBT - Narrative (Details)

DEBT - Narrative (Details) $ / shares in Units, shares in Thousands	1 Months Ended						12 Months Ended
	Oct. 31, 2022 USD ($)	Jun. 30, 2022 USD ($)	Feb. 28, 2022 USD ($) tranche $ / shares shares	Jun. 30, 2021 USD ($)	Nov. 30, 2020 USD ($)	Jul. 31, 2020 USD ($)	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)
Debt Instrument [Line Items]
Proceeds from the issuance of debt							$ 0	$ 128,863,000
Reclassification of warrant liabilities into equity								712,000
2020 Loan Agreement | Secured Debt
Debt Instrument [Line Items]
Total long-term debt							$ 200,000,000
Annual interest rate (as a percent)							8.30%
Equal payments of principal and interest period if interest only period is extended (in months)							23 months
Upfront licensing or partnership proceeds raised							$ 100,000,000
Equal payments of principal period if interest only period is extended (in months)							11 months
Percentage of principal amount for final payment (as a percent)							9%
Periodic payment terms, final payment amount							$ 18,000,000
Minimum cash balance							20,000,000
Debt interest expense							31,800,000	18,200,000
Amortization of debt discount and accretion							$ 4,900,000	3,400,000
2020 Loan Agreement | Secured Debt | Warrants Issued Concurrently With 2022 Loan Agreement
Debt Instrument [Line Items]
Warrants issued (in shares) | shares			40
Warrant price (in dollars per share) | $ / shares			$ 45
Reclassification of warrant liabilities into equity			$ 700,000
2020 Loan Agreement | Secured Debt | Minimum
Debt Instrument [Line Items]
Prepayment fee (as a percent)							1%
2020 Loan Agreement | Secured Debt | Maximum
Debt Instrument [Line Items]
Prepayment fee (as a percent)							3%
2020 Loan Agreement | Secured Debt | Secured Overnight Financing Rate (SOFR) | Debt Instrument Rate One
Debt Instrument [Line Items]
Basis spread on variable rate (as a percent)							0.10%
2020 Loan Agreement | Secured Debt | Secured Overnight Financing Rate (SOFR) | Debt Instrument Rate Two
Debt Instrument [Line Items]
Basis spread on variable rate (as a percent)							8.19%
2020 Term A | Secured Debt
Debt Instrument [Line Items]
Proceeds from the issuance of debt						$ 10,000,000
Total long-term debt							$ 10,900,000	10,900,000
2020 Term B | Secured Debt
Debt Instrument [Line Items]
Proceeds from the issuance of debt					$ 20,000,000
Total long-term debt							21,800,000	21,800,000
2020 Term C | Secured Debt
Debt Instrument [Line Items]
Proceeds from the issuance of debt				$ 40,000,000
Total long-term debt							43,600,000	43,600,000
2020 Term D | Secured Debt
Debt Instrument [Line Items]
Proceeds from the issuance of debt			$ 40,000,000
Number of additional tranches available upon contingent events | tranche			3
Total long-term debt							43,600,000	43,600,000
2020 Term E | Secured Debt
Debt Instrument [Line Items]
Proceeds from the issuance of debt		$ 30,000,000
Total long-term debt							32,700,000	32,700,000
2020 Term F | Secured Debt
Debt Instrument [Line Items]
Proceeds from the issuance of debt		$ 30,000,000
Total long-term debt							32,700,000	32,700,000
2020 Term G | Secured Debt
Debt Instrument [Line Items]
Proceeds from the issuance of debt	$ 30,000,000
Term loan aggregate amount	$ 30,000,000
Total long-term debt							$ 32,700,000	$ 32,700,000

DEBT - Outstanding Debt Balance

DEBT - Outstanding Debt Balance 2020 Loan Agreement (Details) - Secured Debt - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
2020 Loan Agreement
Debt Instrument [Line Items]
Term loan	$ 218,000
Less: debt discount	(11,032)	$ (15,931)
Total debt	206,968	202,069
2020 Term A
Debt Instrument [Line Items]
Term loan	10,900	10,900
2020 Term B
Debt Instrument [Line Items]
Term loan	21,800	21,800
2020 Term C
Debt Instrument [Line Items]
Term loan	43,600	43,600
2020 Term D
Debt Instrument [Line Items]
Term loan	43,600	43,600
2020 Term E
Debt Instrument [Line Items]
Term loan	32,700	32,700
2020 Term F
Debt Instrument [Line Items]
Term loan	32,700	32,700
2020 Term G
Debt Instrument [Line Items]
Term loan	$ 32,700	$ 32,700

DEBT - Future Minimum Payments

DEBT - Future Minimum Payments (Details) - 2020 Loan Agreement - Secured Debt - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Debt Instrument [Line Items]
2025	$ 86,956
2026	104,348
2027	26,696
Total future minimum payments	218,000
Less: unamortized debt discount	(11,032)	$ (15,931)
Total debt	$ 206,968	$ 202,069

STOCKHOLDERS_ EQUITY - Narrativ

STOCKHOLDERS’ EQUITY - Narrative (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended		12 Months Ended
	Aug. 31, 2023	Sep. 30, 2021	Dec. 31, 2023	Dec. 31, 2022
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Costs associated with the ATM offering			$ 0	$ 390
Proceeds from issuance of common stock and pre-funded warrants in private placement			$ 355	$ 0
Sales Agreement
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate offering price		$ 200,000
Commission (as a percent)		3%		2%
Sale of stock, shares issued/sold (in shares)			0	4,332,354
Sale of stock, proceeds received				$ 127,400
Costs associated with the ATM offering				2,600
Costs associated with the ATM offering, additional				$ 400
Private Placement
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Sale of stock, shares issued/sold (in shares)	3,621,314
Sale of stock, proceeds received	$ 200,000
Sale of stock, price per share (in dollars per share)	$ 19.35
Proceeds from issuance of common stock and pre-funded warrants in private placement	$ 400
Private Placement | Warrants, Pre-Funded
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares of common stock issuable upon exercise of warrants (in shares)	6,714,636
Purchase price (in dollars per share)	$ 19.3499
Exercise price (in dollars per share)	$ 0.0001

STOCKHOLDERS_ EQUITY - Warrants

STOCKHOLDERS’ EQUITY - Warrants Issued in Connection with Amended 2020 Loan Agreement (Details)	Dec. 31, 2023 $ / shares shares
July 15, 2030
Class of Warrant or Right [Line Items]
Shares of Common Stock Issuable Upon Exercise of Warrants (in shares) | shares	7,354
Exercise Price per Share (in dollars per share) | $ / shares	$ 17
February 18, 2032
Class of Warrant or Right [Line Items]
Shares of Common Stock Issuable Upon Exercise of Warrants (in shares) | shares	40,000
Exercise Price per Share (in dollars per share) | $ / shares	$ 45

STOCKHOLDERS_ EQUITY - Common S

STOCKHOLDERS’ EQUITY - Common Stock Reserved for Future Issuance (Details) - shares shares in Thousands	Dec. 31, 2023	Dec. 31, 2022
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for issuance (in shares)	13,789	5,514
Options to purchase common stock issued and outstanding
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for issuance (in shares)	6,494	5,305
Shares available for future equity grants
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for issuance (in shares)	533	162
Pre-funded warrants issued and outstanding
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for issuance (in shares)	6,715	0
Warrants issued and outstanding
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for issuance (in shares)	47	47

EQUITY COMPENSATION PLAN - Narr

EQUITY COMPENSATION PLAN - Narrative (Details) - USD ($) shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized (in shares)	7.8
Available shares reserved for issuance (in shares)	0.5
Aggregate intrinsic value of options exercised	$ 2.1	$ 3.7
Total fair value of stock options	$ 24.9	$ 25
Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period (in years)	4 years
Contractual term (in years)	10 years
Unrecognized stock-based compensation expense	$ 51.8
Weighted-average period of recognition (in years)	2 years 6 months
Stock Option | Cliff Vesting
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period (in years)	1 year

EQUITY COMPENSATION PLAN - Stoc

EQUITY COMPENSATION PLAN - Stock Option Activity (Details) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2023 USD ($) $ / shares shares
Number of Shares
Outstanding, beginning balance (in shares) | shares	5,305
Granted (in shares) | shares	1,615
Forfeited (in shares) | shares	(242)
Exercised (in shares) | shares	(184)
Outstanding, ending balance (in shares) | shares	6,494
Vested and exercisable (in shares) | shares	3,322
Weighted Average Exercise Price
Outstanding, beginning balance (in dollars per share) | $ / shares	$ 22.95
Granted (in dollars per share) | $ / shares	22.98
Forfeited (in dollars per share) | $ / shares	23.88
Exercised (in dollars per share) | $ / shares	12.59
Outstanding, ending balance (in dollars per share) | $ / shares	23.22
Vested and exercisable (in dollars per share) | $ / shares	$ 21.80
Weighted Average Remaining Contractual Term (in years)	7 years 7 months 6 days
Weighted Average Remaining Contractual Term, Vested and Exercisable (in years)	6 years 7 months 6 days
Aggregate Intrinsic Value | $	$ 96,548
Aggregate Intrinsic Value, Vested and Exercisable | $	$ 54,101

EQUITY COMPENSATION PLAN - Fair

EQUITY COMPENSATION PLAN - Fair Value of Stock Option Grants (Details) - $ / shares	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average fair value (in dollars per share)	$ 16.88	$ 17.72
Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rate (as a percent)	3.77%	2.63%
Expected volatility (as a percent)	84.31%	85.26%
Expected dividend yield (as a percent)	0%	0%
Expected term (in years)	6 years 29 days	6 years 29 days

EQUITY COMPENSATION PLAN - St_2

EQUITY COMPENSATION PLAN - Stock-based Compensation Expense (Details) - Stock Option - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	$ 24,846	$ 20,450
Research and development
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	16,630	14,513
General and administrative
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	$ 8,216	$ 5,937

LICENSE AND GRANT REVENUES - Re

LICENSE AND GRANT REVENUES - Revenue Summary (Details) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Collaborative Arrangements And Noncollaborative Arrangement Transactions Line Items
Total revenue	$ 1,800,000	$ 2,192,000
License fee revenue
Collaborative Arrangements And Noncollaborative Arrangement Transactions Line Items
Total revenue	1,800,000	2,178,000
License fee revenue | Phylaxis BioScience, LLC
Collaborative Arrangements And Noncollaborative Arrangement Transactions Line Items
Total revenue	1,634,000	1,101,000
License fee revenue | Chiesi Farmaceutici S.p.A.
Collaborative Arrangements And Noncollaborative Arrangement Transactions Line Items
Total revenue	166,000	877,000
License fee revenue | 2seventy bio, Inc.
Collaborative Arrangements And Noncollaborative Arrangement Transactions Line Items
Total revenue	0	200,000
Grant revenue
Collaborative Arrangements And Noncollaborative Arrangement Transactions Line Items
Total revenue	0	14,000
Grant revenue | Congressionally Directed Medical Research Program
Collaborative Arrangements And Noncollaborative Arrangement Transactions Line Items
Total revenue	$ 0	$ 14,000

LICENSE AND GRANT REVENUES - Li

LICENSE AND GRANT REVENUES - License and Collaboration Agreements (Details)		1 Months Ended				3 Months Ended	12 Months Ended
	Jul. 24, 2023	Jun. 30, 2022 USD ($) program	Jun. 30, 2020 USD ($) program performanceObligation	Aug. 31, 2019 USD ($)	May 31, 2019 performanceObligation	Dec. 31, 2023 USD ($) option	Dec. 31, 2023 USD ($) option	Dec. 31, 2022 USD ($)	Dec. 31, 2020 USD ($)	Jul. 31, 2020 USD ($)
Collaborative Arrangements And Noncollaborative Arrangement Transactions Line Items
Deferred revenue						$ 0	$ 0	$ 166,000
Total revenue							1,800,000	2,192,000
License fee revenue
Collaborative Arrangements And Noncollaborative Arrangement Transactions Line Items
Total revenue							$ 1,800,000	2,178,000
Phylaxis BioScience, LLC
Collaborative Arrangements And Noncollaborative Arrangement Transactions Line Items
Equity interest percentage (as a percent)						15%	15%			10%
Equity method investment, ownership percentage, increase during period (as a percent)						5%
Equity method investment						$ 0	$ 0	0	$ 0	$ 500,000
Phylaxis BioScience, LLC
Collaborative Arrangements And Noncollaborative Arrangement Transactions Line Items
Payments received pursuant to agreement										5,000,000
Development milestone payment receivable										225,000,000
Commercialization milestone payment receivable										175,000,000
Collaborative arrangement, payment received, net										$ 5,500,000
Equity method investment						1,600,000	1,600,000
Phylaxis BioScience, LLC | License fee revenue
Collaborative Arrangements And Noncollaborative Arrangement Transactions Line Items
Revenue recognized related to performance obligation							1,600,000	1,100,000
Deferred revenue						0	0	0
Total revenue							1,634,000	1,101,000
Chiesi Farmaceutici S.p.A.
Collaborative Arrangements And Noncollaborative Arrangement Transactions Line Items
Deferred revenue						$ 0	0
Nonrefundable, upfront payment				$ 10,000,000
Number of performance obligations | performanceObligation					1
Term of research and development services option period (in days)					60 days
Term of option period due from deliverables (in days)	60 days
Deferred revenue								100,000
Chiesi Farmaceutici S.p.A. | License fee revenue
Collaborative Arrangements And Noncollaborative Arrangement Transactions Line Items
Revenue recognized related to performance obligation							100,000	900,000
Total revenue							$ 166,000	877,000
2seventy bio, Inc. | Initial Programs
Collaborative Arrangements And Noncollaborative Arrangement Transactions Line Items
Nonrefundable, upfront payment			$ 400,000
Number of performance obligations | performanceObligation			1
Number of programs related to collaborative agreement | program		3	2
Number of options exercised | option						1	1
Number of options declined | option						1	1
2seventy bio, Inc. | Additional Programs
Collaborative Arrangements And Noncollaborative Arrangement Transactions Line Items
Number of programs related to collaborative agreement | program			8
2seventy bio, Inc. | Initial Programs, Program 1
Collaborative Arrangements And Noncollaborative Arrangement Transactions Line Items
Nonrefundable, upfront payment			$ 200,000
2seventy bio, Inc. | Initial Programs, Program 2
Collaborative Arrangements And Noncollaborative Arrangement Transactions Line Items
Nonrefundable, upfront payment			200,000
2seventy bio, Inc. | Initial Programs, Program 3
Collaborative Arrangements And Noncollaborative Arrangement Transactions Line Items
Nonrefundable, upfront payment		$ 200,000
2seventy bio, Inc. | 2020 Option And License Agreement
Collaborative Arrangements And Noncollaborative Arrangement Transactions Line Items
Development milestone payment receivable			$ 51,500,000
2seventy bio, Inc. | License fee revenue
Collaborative Arrangements And Noncollaborative Arrangement Transactions Line Items
Total revenue							$ 0	$ 200,000

LICENSE AND GRANT REVENUES - Go

LICENSE AND GRANT REVENUES - Government Grants (Details) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Feb. 28, 2021
Collaborative Arrangements And Noncollaborative Arrangement Transactions Line Items
Total revenue	$ 1,800,000	$ 2,192,000
Grant revenue
Collaborative Arrangements And Noncollaborative Arrangement Transactions Line Items
Total revenue	0	14,000
Congressionally Directed Medical Research Program
Collaborative Arrangements And Noncollaborative Arrangement Transactions Line Items
Grant award			$ 300,000
Congressionally Directed Medical Research Program | Grant revenue
Collaborative Arrangements And Noncollaborative Arrangement Transactions Line Items
Total revenue	$ 0	$ 14,000

INCOME TAXES - Components of In

INCOME TAXES - Components of Income Tax Expense (Benefit) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Income Tax Disclosure [Abstract]
State	$ 3	$ 3
Provision for income taxes	$ 3	$ 3

INCOME TAXES - Reconciliation o

INCOME TAXES - Reconciliation of Income Tax Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Income Tax Disclosure [Abstract]
Expected income tax benefit at federal statutory rate	$ (50,684)	$ (30,497)
State income tax expense (benefit), net of federal benefit	(3,568)	(2,495)
Permanent items	1,524	583
R&D credits	(2,322)	(1,261)
Unrecognized tax benefits (FIN 48)	1,054	751
Return to provision true-ups	(420)	(135)
Valuation allowance	54,419	33,057
Provision for income taxes	$ 3	$ 3

INCOME TAXES - Components of Ne

INCOME TAXES - Components of Net Deferred Income Taxes (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Deferred income tax assets
Net operating loss carryforward	$ 68,254	$ 52,970
Research and development credits	12,648	9,728
Intangibles	3,289	3,684
Accruals	1,412	696
Stock compensation	8,581	5,130
Capitalized research and development costs	51,772	19,585
Deferred revenue	0	37
Operating lease liabilities	697	1,118
Other	10	0
Gross deferred tax assets	146,663	92,948
Less: Valuation allowance	(146,005)	(91,586)
Total deferred tax assets	658	1,362
Deferred income tax liabilities
Fixed assets	(10)	(35)
Operating lease right-of-use assets	(648)	(1,048)
Other	0	(279)
Total deferred tax liabilities	(658)	(1,362)
Net deferred tax assets (liabilities)	0	0
Net deferred tax assets (liabilities)	$ 0	$ 0

INCOME TAXES - Narrative (Detai

INCOME TAXES - Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Tax Credit Carryforward [Line Items]
Deferred tax asset valuation allowance	$ 146,005,000	$ 91,586,000
Gross unrecognized tax benefits	4,651,000	3,597,000	$ 2,846,000
Accrual for interest and penalties	0	0
Recognized interest and penalties	0	$ 0
Federal
Tax Credit Carryforward [Line Items]
Net operating loss carryforwards	305,100,000
Federal | Research Tax Credit Carryforward
Tax Credit Carryforward [Line Items]
Tax credit carryforward	12,400,000
State
Tax Credit Carryforward [Line Items]
Net operating loss carryforwards	65,300,000
State | Research Tax Credit Carryforward
Tax Credit Carryforward [Line Items]
Tax credit carryforward	$ 6,200,000

INCOME TAXES - Unrecognized Tax

INCOME TAXES - Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Unrecognized Tax Benefits [Roll Forward]
Beginning balance	$ 3,597	$ 2,846
Increases related to current year tax positions	1,054	751
Ending balance	$ 4,651	$ 3,597

LEASES - Narrative (Details)

LEASES - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	May 31, 2019	Sep. 30, 2017
Leases [Abstract]
Lease agreement term (in years)				7 years
Lease extension term (in years)				5 years
Initial base rent per month			$ 30	$ 100
Annual escalations (as a percent)			2%	2%
Operating lease expense	$ 3,700	$ 3,400
Payments included in measurement of lease liability	$ 2,200	$ 2,200
Remaining term of operating lease (in years)	1 year 6 months	2 years 6 months
Weighted-average discount rate (as a percent)	8.20%	8.20%

LEASES - Schedule of Right-Of-U

LEASES - Schedule of Right-Of-Use Asset and Operating Lease Liability (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Leases [Abstract]
Operating right-of-use asset	$ 2,952	$ 4,717
Operating lease liability
Current	2,063	1,860
Non-current	1,110	3,173
Present value of operating lease liability	$ 3,173	$ 5,033

LEASES - Schedule of Operating

LEASES - Schedule of Operating Lease Liability Maturity (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Leases [Abstract]
2024	$ 2,247
2025	1,137
Total future minimum lease payments	3,384
Less: imputed interest	(211)
Present value of operating lease liability	3,173	$ 5,033
Less: current portion of operating lease liability	(2,063)	(1,860)
Non-current portion of lease liability	$ 1,110	$ 3,173

COMMITMENTS AND CONTINGENCIES (

COMMITMENTS AND CONTINGENCIES (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Commitments and Contingencies Disclosure [Abstract]
Purchase commitment, future period (in months)	12 months
Purchase commitment	$ 62.8	$ 74.8
Purchase commitment, expenses incurred	44.5	$ 0.3
Legal Merger Contingency Fee
Loss Contingencies [Line Items]
Contingency accrual	$ 20

SUBSEQUENT EVENTS (Details)

SUBSEQUENT EVENTS (Details) - Subsequent Event $ / shares in Units, $ in Millions	Jan. 22, 2024 USD ($) right $ / shares
Subsequent Event [Line Items]
Sale of stock, price per share (in dollars per share) | $ / shares	$ 30
Sale of stock, right per share, contingency | right	1
Sale of stock, price per share, contingency (in dollars per share) | $ / shares	$ 5
Exchange ratio	4
Payments for merger	$ 200
Ownership percentage	8%
Exchange ratio, pro-rate basis (as a percent)	92%
Exchange ratio, pro-rate basis, post spin-off transaction (as a percent)	8%
Consideration transferred	$ 2,200
Termination fee	$ 54.5
Consummation threshold	50%
Reverse termination fee	$ 92.1