Equillium (EQ) 10-Q 8 Aug 24 2024 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2024	Aug. 05, 2024
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2024
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	Q2
Entity Registrant Name	EQUILLIUM, INC.
Entity Central Index Key	0001746466
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Common Stock, Shares Outstanding		35,424,388
Entity Shell Company	false
Entity Small Business	true
Entity Emerging Growth Company	false
Trading Symbol	EQ
Title of 12(b) Security	Common Stock, par value $0.0001 per share
Security Exchange Name	NASDAQ
Entity File Number	001-38692
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	82-1554746
Entity Address, Address Line One	2223 Avenida de la Playa
Entity Address, Address Line Two	Suite 105
Entity Address, City or Town	La Jolla
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	92037
City Area Code	858
Local Phone Number	240-1200
Document Quarterly Report	true
Document Transition Report	false

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Current assets:
Cash and cash equivalents	$ 11,057	$ 23,216
Estimated Fair Value	22,242	17,650
Accounts receivable	5,893	3,735
Prepaid expenses and other current assets	2,695	4,748
Total current assets	41,887	49,349
Operating lease right-of-use assets	592	796
Property and equipment, net	329	315
Other assets	53	70
Total assets	42,861	50,530
Current liabilities:
Accounts payable	4,486	4,707
Accrued expenses	6,903	6,697
Current portion of deferred revenue	8,430	15,729
Current portion of operating lease liabilities	350	440
Total current liabilities	20,169	27,573
Long-term operating lease liabilities	259	384
Total liabilities	20,428	27,957
Commitments and contingencies
Stockholders' equity:
Common stock, $0.0001 par value; 200,000,000 shares authorized as of June 30, 2024 and December 31, 2023; 35,424,388 and 35,254,752 shares issued and outstanding as of June 30, 2024 and December 31, 2023, respectively	3	3
Additional paid-in capital	210,185	208,170
Accumulated other comprehensive income	251	140
Accumulated deficit	(188,006)	(185,740)
Total stockholders' equity	22,433	22,573
Total liabilities and stockholders' equity	$ 42,861	$ 50,530

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) - $ / shares	Jun. 30, 2024	Dec. 31, 2023
Statement of Financial Position [Abstract]
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares authorized	200,000,000	200,000,000
Common stock, shares issued	35,424,388	35,254,752
Common stock, shares outstanding	35,424,388	35,254,752

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations and Comprehensive Income (Loss) (Unaudited) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Income Statement [Abstract]
Revenue	$ 13,853,000	$ 9,124,000	$ 24,542,000	$ 18,003,000
Operating expenses:
Research and development	10,808,000	9,610,000	20,551,000	18,882,000
General and administrative	3,145,000	3,105,000	6,883,000	6,820,000
Total operating expenses	13,953,000	12,715,000	27,434,000	25,702,000
Loss from operations	(100,000)	(3,591,000)	(2,892,000)	(7,699,000)
Other income, net:
Interest expense		(259,000)		(491,000)
Interest income	371,000	627,000	811,000	1,266,000
Other income (expense), net	197,000	(112,000)	(185,000)	(291,000)
Total other income, net	568,000	256,000	626,000	484,000
Income (loss) before income taxes	468,000	(3,335,000)	(2,266,000)	(7,215,000)
Income tax expense	0	8,000	0	68,000
Net income (loss)	468,000	(3,343,000)	(2,266,000)	(7,283,000)
Other comprehensive income (loss), net:
Unrealized (loss) gain on available-for-sale securities, net	(6,000)	(36,000)	(28,000)	59,000
Foreign currency translation (loss) gain	(166,000)	71,000	139,000	205,000
Total other comprehensive (loss) income, net	(172,000)	35,000	111,000	264,000
Comprehensive income (loss)	$ 296,000	$ (3,308,000)	$ (2,155,000)	$ (7,019,000)
Net income (loss) share, basic	$ 0.01	$ (0.1)	$ (0.06)	$ (0.21)
Net income (loss) per share, diluted	$ 0.01	$ (0.1)	$ (0.06)	$ (0.21)
Weighted-average number of common shares outstanding, basic	35,292,035	34,449,769	35,273,394	34,432,057
Weighted-average number of common shares outstanding, diluted	36,589,774	34,449,769	35,273,394	34,432,057

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Stockholders' Equity (Unaudited) - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Income	Accumulated Deficit
Balance at Dec. 31, 2022	$ 31,942	$ 3	$ 204,268	$ 76	$ (172,405)
Balance, Shares at Dec. 31, 2022		34,414,149
Stock-based compensation expense	1,038		1,038
Other comprehensive income	229			229
Net Income (Loss)	(3,940)				(3,940)
Balance at Mar. 31, 2023	29,269	$ 3	205,306	305	(176,345)
Balance, Shares at Mar. 31, 2023		34,414,149
Balance at Dec. 31, 2022	31,942	$ 3	204,268	76	(172,405)
Balance, Shares at Dec. 31, 2022		34,414,149
Other comprehensive income	264
Net Income (Loss)	(7,283)
Balance at Jun. 30, 2023	26,981	$ 3	206,326	340	(179,688)
Balance, Shares at Jun. 30, 2023		34,568,500
Balance at Mar. 31, 2023	29,269	$ 3	205,306	305	(176,345)
Balance, Shares at Mar. 31, 2023		34,414,149
Issuance of common stock under employee stock purchase plan	86		86
Issuance of common stock under employee stock purchase plan, Shares		154,351
Stock-based compensation expense	934		934
Other comprehensive income	35			35
Net Income (Loss)	(3,343)				(3,343)
Balance at Jun. 30, 2023	26,981	$ 3	206,326	340	(179,688)
Balance, Shares at Jun. 30, 2023		34,568,500
Balance at Dec. 31, 2023	22,573	$ 3	208,170	140	(185,740)
Balance, Shares at Dec. 31, 2023		35,254,752
Stock-based compensation expense	972		972
Other comprehensive income	283			283
Net Income (Loss)	(2,734)				(2,734)
Balance at Mar. 31, 2024	21,094	$ 3	209,142	423	(188,474)
Balance, Shares at Mar. 31, 2024		35,254,752
Balance at Dec. 31, 2023	22,573	$ 3	208,170	140	(185,740)
Balance, Shares at Dec. 31, 2023		35,254,752
Other comprehensive income	111
Net Income (Loss)	(2,266)
Balance at Jun. 30, 2024	22,433	$ 3	210,185	251	(188,006)
Balance, Shares at Jun. 30, 2024		35,424,388
Balance at Mar. 31, 2024	21,094	$ 3	209,142	423	(188,474)
Balance, Shares at Mar. 31, 2024		35,254,752
Issuance of common stock under employee stock purchase plan	91		91
Issuance of common stock under employee stock purchase plan, Shares		169,636
Stock-based compensation expense	952		952
Other comprehensive income	(172)			(172)
Net Income (Loss)	468				468
Balance at Jun. 30, 2024	$ 22,433	$ 3	$ 210,185	$ 251	$ (188,006)
Balance, Shares at Jun. 30, 2024		35,424,388

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023
Operating activities:
Net loss	$ (2,266)	$ (7,283)
Adjustments to reconcile net loss to cash used in operating activities:
Depreciation	67	62
Stock-based compensation	1,924	1,972
Net unrealized loss on foreign currency transactions	159	270
Amortization of term loan discount and issuance costs		180
Amortization of investments, net	(519)	(597)
Deferred revenue	(7,298)	(4,882)
Changes in operating assets and liabilities:
Accounts receivable	(2,159)	(905)
Prepaid expenses and other current assets	2,008	(2,421)
Accounts payable	(203)	(930)
Accrued expenses	228	332
Right-of-use assets and lease liabilities, net	(11)	(8)
Net cash used in operating activities	(8,070)	(14,210)
Investing activities:
Purchases of property and equipment	(81)
Purchases of short-term investments	(17,601)	(37,181)
Maturities of short-term investments	13,500	27,000
Net cash used in investing activities	(4,182)	(10,181)
Financing activities:
Repayment of notes payable		(9,133)
Net cash provided by (used in) financing activities	91	(9,047)
Effect of exchange rate changes on cash and cash equivalents	2	(45)
Net decrease in cash and cash equivalents	(12,159)	(33,483)
Cash and cash equivalents at beginning of period	23,216	59,107
Cash and cash equivalents at end of period	11,057	25,624
Follow-on Offering
Financing activities:
Proceeds from issuance of common stock under employee stock purchase plan	$ 91	$ 86

Pay vs Performance Disclosure

Pay vs Performance Disclosure - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2024	Mar. 31, 2024	Jun. 30, 2023	Mar. 31, 2023	Jun. 30, 2024	Jun. 30, 2023
Pay vs Performance Disclosure
Net Income (Loss)	$ 468	$ (2,734)	$ (3,343)	$ (3,940)	$ (2,266)	$ (7,283)

Insider Trading Arrangements

Insider Trading Arrangements	3 Months Ended	6 Months Ended
	Jun. 30, 2024 shares	Jun. 30, 2024 shares
Trading Arrangements, by Individual
Material Terms of Trading Arrangement		Trading Arrangements During the three-months ended June 30, 2024, one of our officers (as defined in Rule 16a-1(f) under the Exchange Act) adopted or terminated the contracts, instructions or written plans for the purchase or sale of our securities set forth in the table below: Type of Trading Arrangement Total Shares Name and Position Action Adoption/Termination Rule (1) Non-Rule (2) Stock to be Expiration Date Penny Tom , SVP Finance and Principal Accounting Officer Adoption June 14, 2024 X 265,523 June 14, 2025 (1) Contract, instruction or written plan intended to satisfy the affirmative defense conditions of Rule 10b5-1(c) under the Exchange Act. (2) “ No n-Rule 10b5-1 trading arrangement” as defined in Item 408(c) of Regulation S-K under the Exchange Act.
Name	Penny Tom
Title	SVP Finance and Principal Accounting Officer
Rule 10b5-1 Arrangement Adopted	true
Non-Rule 10b5-1 Arrangement Adopted	false
Adoption Date	June 14, 2024
Aggregate Available	265,523	265,523
Expiration Date	June 14, 2025

Organization and Accounting Pro

Organization and Accounting Pronouncements	6 Months Ended
	Jun. 30, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization and Accounting Pronouncements	1. Organization and Accounting Pronouncements Description of Business Equillium, Inc. (the Company) was incorporated in the state of Delaware on March 16, 2017 . The Company is a clinical-stage biotechnology company leveraging a deep understanding of immunobiology to develop novel therapeutics to treat severe autoimmune and inflammatory (immuno-inflammatory) disorders with high unmet medical need. The Company’s strategy is focused on advancing the clinical development of its product candidates, including potentially pursuing additional indications and acquiring new product candidates and platforms to expand its pipeline. The Company intends to commercialize its product candidates either independently or through partnerships or otherwise monetize its pipeline through strategic transactions. The Company's current clinical-stage product candidates consist of EQ101 and itolizumab (EQ001). EQ101 is a clinical-stage, first-in-class, selective tri-specific inhibitor of IL-2, IL-9 and IL-15, key disease-driving, clinically validated cytokine targets aimed at addressing unmet needs across a range of immuno-inflammatory indications. Itolizumab (EQ001) is a clinical-stage, first-in-class anti-CD6 monoclonal antibody that selectively targets the CD6-ALCAM signaling pathway to downregulate pathogenic T effector cells while preserving T regulatory cells critical for maintaining a balanced immune response. This pathway plays a central role in modulating the activity and trafficking of T cells that drive a number of immuno-inflammatory diseases. The Company is also engaged in the discovery and optimization of additional peptide-based product candidates that selectively target multiple cytokines and is currently advancing the development of EQ302, a preclinical-stage, first-in-class, selective bi-specific inhibitor of IL-15 and IL-21 for oral delivery. The Company’s novel and differentiated pipeline of first-in-class immunology assets has the potential to address unmet medical needs in numerous areas, including dermatology, gastroenterology, rheumatology, hematology, transplant science, oncology and pulmonology. The Company is focused on developing EQ101, EQ302 and itolizumab (EQ001) as potential best-in-class, disease modifying treatments for multiple severe immuno-inflammatory disorders. From inception through June 30, 2024, the Company has devoted substantially all of its efforts to organizing and staffing the Company, business planning, raising capital, in-licensing rights to itolizumab (EQ001), conducting non-clinical research, including the initial preclinical development of EQ302, filing three Investigational New Drug applications (INDs), conducting clinical development of EQ101, EQ102 and itolizumab (EQ001), conducting chemistry, manufacturing and controls (CMC) activities in preparation for a potential biologics license application (BLA) filing for itolizumab, conducting formulation development work of our product candidates, conducting business development activities such as the acquisition of Bioniz Therapeutics, Inc. (Bioniz), the Asset Purchase Agreement with Ono Pharmaceutical Co., Ltd. (Ono) and other transactions not completed, initiating a stock repurchase program, and the general and administrative activities associated with operating a public company. In addition, the Company has not generated revenues from product sales, milestone payments, or royalties, and the sales and income potential of its business is unproven. Liquidity and Business Risks As of June 30, 2024, the Company had $ 33.3 million in cash, cash equivalents and short-term investments. The Company has incurred significant operating losses and negative cash flows from operations. The Company expects to use its cash, cash equivalents, and short-term investments primarily for clinical development, non-clinical research, CMC activities, formulation and device development activities, product supply, potential acquisition of new products, potential repurchases of shares of its common stock under its stock repurchase program, legal and other regulatory compliance, employee compensation and related expenses, insurance premiums, working capital and other general overhead costs. The Company does not expect to generate any revenues from product sales unless and until the Company successfully completes development and obtains regulatory approval of any of its product candidates, which is unlikely to happen within the next 12 months, if ever. Accordingly, until such time as the Company can generate significant revenue from sales of its product candidates, if ever, the Company expects to finance its cash needs through a combination of equity offerings, debt financings, and collaboration and license agreements, such as its Asset Purchase Agreement with Ono. However, the Company may not be able to secure additional financing or enter into such other arrangements in a timely manner or on favorable terms, if at all. As a result of the conflict between Russia and Ukraine, the conflict in the Middle East, bank failures, inflationary pressures on the economy and monetary policy responses taken by government agencies and other macroeconomic factors, the global credit and financial markets have experienced extreme volatility, including diminished liquidity and credit availability, declines in consumer confidence, declines in economic growth and uncertainty about economic stability. There can be no assurance that further deterioration in credit and financial markets and confidence in economic conditions will not occur. If equity and credit markets deteriorate, it may make any necessary debt or equity financing more difficult to obtain, more costly and/or more dilutive. The Company’s failure to raise capital or enter into such other arrangements when needed would have a negative impact on the Company’s financial condition and could force the Company to delay, reduce or terminate its research and development programs or other operations, or grant rights to develop and market product candidates that the Company would otherwise prefer to develop and market itself. If Ono does not exercise its option, management believes that the Company’s cash, cash equivalents and short-term investments as of June 30, 2024, will be sufficient to fund operations for at least the next 12 months from the date this Quarterly Report on Form 10-Q is filed with the Securities and Exchange Commission (SEC), based on certain assumptions. Specifically, management’s projected cash runway assumes Ono continues to fund itolizumab (EQ001) development costs through October 2024, the Company pauses further development of a pre-filled syringe presentation for itolizumab (EQ001) and the Company pauses further CMC studies and other activities in preparation for a potential BLA filing for itolizumab (EQ001) without incurring additional costs. It also assumes no further repurchases of stock under the Company’s stock repurchase program, the reduction of certain discretionary compensation expenses and the elimination of non-essential discretionary expenditures, including travel. If Ono exercises its option, management believes that the Company’s cash, cash equivalents and short-term investments as of June 30, 2024, including the proceeds received from the exercise of Ono’s option, will be sufficient to fund the Company’s operations for at least the next 12 months from the date of this filing without implementing or taking into account any of the aforementioned actions or assumptions. Basis of Presentation The accompanying condensed consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles (GAAP) and the rules and regulations of the SEC related to a quarterly report on Form 10-Q. Any reference in these notes to applicable guidance is meant to refer to GAAP as found in the Accounting Standards Codification (ASC) and Accounting Standards Updates (ASU) promulgated by the Financial Accounting Standards Board (FASB). Certain information and note disclosures normally included in annual financial statements prepared in accordance with GAAP have been condensed or omitted pursuant to those rules and regulations. The condensed consolidated financial statements reflect all adjustments which, in the opinion of management, are necessary for a fair statement of the results for the periods presented. All such adjustments are of a normal and recurring nature. The operating results presented in these condensed consolidated financial statements are not necessarily indicative of the results that may be expected for any future periods. These condensed consolidated financial statements should be read in conjunction with the audited financial statements and the notes thereto for the year ended December 31, 2023 included in the Company’s Annual Report on Form 10-K filed with the SEC on March 25, 2024. Reclassifications Certain reclassifications have been made to prior-year amounts to conform to the current period presentation. Principles of Consolidation The accompanying condensed consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries. All intercompany transactions and balances have been eliminated in consolidation. Foreign Currency Translation The Company’s wholly-owned subsidiary in Australia uses its local currency as its functional currency. Assets and liabilities are translated into U.S. dollars at quarter-end exchange rates and revenues and expenses are translated at average exchange rates during the quarter and year-to-date periods. Foreign currency translation adjustments for the reported periods are included in accumulated other comprehensive (loss) income, net in the Company’s condensed consolidated statements of comprehensive loss, and the cumulative effect is included in accumulated other comprehensive income in the stockholders’ equity section of the Company’s condensed consolidated balance sheets. Recently Issued and Adopted Accounting Pronouncements In October 2021, the FASB issued ASU 2021-08 , Business Combinations (Topic 805): Accounting for Contract Assets and Contract Liabilities from Contracts with Customers, which requires an acquirer to recognize and measure contract assets and liabilities acquired in a business combination in accordance with Revenue from Contracts with Customers (Topic 606) rather than adjust them to fair value at the acquisition date. This update is effective beginning with the Company’s 2024 fiscal year annual reporting period. The Company adopted ASU 2021-08 on January 1, 2024 on a prospective basis. The adoption of this standard did no t have a material impact on the Company’s condensed consolidated financial statements. In November 2023, the FASB issued ASU 2023-07 , Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures, which updates reportable segment disclosure requirements primarily through enhanced disclosures about significant segment expenses. The amendments are effective for fiscal years beginning after December 15, 2023, and for interim periods within fiscal years beginning after December 15, 2024. Early adoption is permitted. The amendments should be applied retrospectively to all prior periods presented in the financial statements. The Company is currently assessing the impact this standard will have on the Company’s condensed consolidated financial statements. In December 2023, the FASB issued ASU 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures. ASU 2023-09 requires annual disclosures of specific categories in the rate reconciliation, additional information for reconciling items that meet a quantitative threshold and a disaggregation of income taxes paid, net of refunds. ASU 2023-09 also eliminates certain existing disclosure requirements related to uncertain tax positions and unrecognized deferred tax liabilities. ASU 2023-09 is effective for the Company beginning with the Company's Annual Report on Form 10-K for the year ending December 31, 2025. Early adoption is permitted. ASU 2023-09 should be applied prospectively. Retrospective adoption is permitted. The Company is currently assessing the impact this standard will have on the Company’s condensed consolidated financial statements. No other new accounting pronouncements or legislation issued or effective as of June 30, 2024 have had, or are expected to have, a material impact on the Company’s condensed consolidated financial statements.

Summary of Significant Accounti

Summary of Significant Accounting Policies	6 Months Ended
	Jun. 30, 2024
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies Use of Estimates The preparation of the Company’s condensed consolidated financial statements requires the Company to make estimates and assumptions that impact the reported amounts of assets, liabilities and expenses and the disclosure of contingent assets and liabilities in the condensed consolidated financial statements and accompanying notes. Significant estimates in the Company’s condensed consolidated financial statements relate to accrued research and development expense, expected refunds from the Australian Taxation Office for eligible research and development activities, revenue recognition and the valuation of equity awards. Management evaluates its estimates on an ongoing basis. Although estimates are based on the Company’s historical experience, knowledge of current events, and actions it may undertake in the future, actual results may ultimately materially differ from these estimates and assumptions. Concentration of Credit Risk and Off-Balance Sheet Ris k Financial instruments which potentially subject the Company to significant concentration of credit risk consist of cash and cash equivalents and short-term investments. The Company maintains deposits in federally insured financial institutions in which the majority of deposits are in excess of federally insured limits. The Company has not experienced any losses in such accounts, and management believes that the Company is not exposed to significant credit risk due to the financial position of the depository institutions in which those deposits are held. The Company’s investment policy includes guidelines for the quality of the related institutions and financial instruments and defines allowable investments that the Company may invest in, which the Company believes minimizes the exposure to concentration of credit risk. Comprehensive Loss The Company is required to report all components of comprehensive loss, including net loss, in the condensed consolidated financial statements in the period in which they are recognized. Comprehensive loss is defined as the change in equity during a period from transactions and other events and circumstances from non-owner sources, including unrealized gains and losses on investments and foreign currency translation gains and losses. Other comprehensive income, net includes unrealized gains or losses on short-term investments as well as foreign currency translation gains or losses. Cash and Cash Equivalents Cash and cash equivalents include cash in readily available checking and savings accounts, and money market funds. The Company considers all highly liquid investments with an original maturity of three months or less from the date of purchase to be cash equivalents. At June 30, 2024 and December 31, 2023, the Company's cash and cash equivalents were primarily comprised of money market funds. Short-Term Investments Available-for-sale securities are carried at fair value, with the unrealized gains and losses reported in comprehensive loss. The amortized cost of available-for-sale debt securities is adjusted for amortization of premiums and accretion of discounts to maturity. Such amortization and accretion are included in interest income. Realized gains and losses and declines in value judged to be other-than-temporary, if any, on available-for-sale securities are included in other income or expense. The cost of securities sold is based on the specific identification method. Interest and dividends on securities classified as available-for-sale are included in interest income. Accounts Receivable Accounts receivable includes trade accounts receivables from the Ono Asset Purchase Agreement (see Note 8). Reimbursable costs that have not been invoiced as of the balance sheet date are recorded as unbilled accounts receivable. As of June 30, 2024 and December 31, 2023, the Company had unbilled accounts receivable totaling $ 5.9 million and $ 3.7 million, respectively, classified as accounts receivable on its condensed consolidated balance sheet. The Company makes judgments as to its ability to collect outstanding receivables and provide an allowance for receivables when collection becomes doubtful. Allowance for credit risk for accounts receivable is established based on various factors including credit profiles of the Company’s customers, historical payments and current economic trends. The Company reviews its allowance for accounts receivable by assessing individual accounts receivable over a specific aging and amount. The estimate of expected credit losses is based on information about past events, current economic conditions, and forecasts of future economic conditions that affect the collectability. Accounts receivable is written-off on a case by case basis, net of any amounts that may be collected. As of June 30, 2024 and December 31, 2023, no credit losses have been recorded by the Company. Prepaid Expenses and Other Current Assets Prepaid expenses and other current assets consisted of the following (in thousands): June 30, December 31, 2024 2023 Australian research and development tax incentive $ 692 $ 2,054 Prepaid clinical development 556 1,008 Prepaid insurance 250 532 Other receivables 407 497 Prepaid other 473 422 Other current assets 317 235 Total prepaid expenses and other current assets $ 2,695 $ 4,748 Property and Equipment Property and equipment is stated at cost and depreciated using the straight-line method over the estimated useful lives of the assets (generally three to five years ). Lea ses The Company determines if an arrangement is a lease at inception. Lease right-of-use assets represent the Company's right to use an underlying asset for the lease term and lease liabilities represent the Company's obligation to make lease payments arising from the lease. For opera ting leases with an initial term greater than 12 months, the Company recognizes operating lease right-of-use assets and operating lease liabilities based on the present value of lease payments over the lease term at the commencement date. Operating lease right-of-use assets are comprised of the lease liability plus any lease payments made and excludes lease incentives. Lease terms include options to renew or terminate the lease when the Company is reasonably certain that the renewal option will be exercised or when it is reasonably certain that the termination option will not be exercised. For the Company's operating leases, if the interest rate used to determine the present value of future lease payments is not readily determinable, the Company estimates its incremental borrowing rate as the discount rate for the lease. The Company's incremental borrowing rate is estimated to approximate the interest rate on a collateralized basis with similar terms and payments, and in similar economic environments. Lease expense for lease payments is recognized on a straight-line basis over the lease term. The Company has elected the practical expedient to not separate lease and non-lease components. Impairment of Long-Lived Assets Long-lived assets consist primarily of property and equipment. An impairment loss is recorded if and when events and circumstances indicate that assets might be impaired and the undiscounted cash flows estimated to be generated by those assets are less than the carrying amount of those assets. While the Company’s current and historical operating losses and negative cash flows are indicators of impairment, management believes that future cash flows to be received support the carrying value of its long-lived assets and, accordingly, has not recognized any impairment losses since inception. Accrued Research and Development Expense The Company is required to estimate its expenses resulting from its obligations under contracts with vendors, consultants and contract research organizations, in connection with conducting research and development activities. The financial terms of these contracts are subject to negotiations, which vary from contract to contract and may result in payment flows that do not match the periods over which materials or services are provided under such contracts. The Company reflects research and development expenses in its condensed consolidated financial statements by matching those expenses with the period in which services and efforts are expended. The Company accounts for these expenses according to the progress of the preclinical or clinical study as measured by the timing of various aspects of the study or related activities. The Company determines accrual estimates through review of the underlying contracts along with preparation of financial models taking into account discussions with research and other key personnel as to the progress of studies, or other services being conducted. During the course of a study, the Company adjusts its rate of expense recognition if actual results differ from its estimates. The Company classifies its estimates for accrued research and development expenses as accrued expenses on the accompanying condensed consolidated balance sheet. Australian Research and Develop ment Tax Incentive Equillium Australia Pty Ltd (Equillium Australia), a wholly-owned subsidiary of Equillium, Inc., is eligible under the Australian Research and Development Tax Incentive Program (the Tax Incentive) to obtain a cash refund from the Australian Taxation Office (ATO) for eligible research and development expenditures. The cash refund is received by Equillium Australia upon filing of a Tax Incentive claim in connection with Equillium Australia’s annual income tax return. The Tax Incentive is a self-assess program whereby Equillium Australia must assess each year (i) if the entity is eligible, (ii) if the specific research and development activities are eligible and (iii) if the individual research and development expenditures have nexus to such research and development activities. Equillium Australia evaluates its eligibility under the Tax Incentive as of each balance sheet date based on the most current and relevant data available. Equillium Australia is able to continue to claim refunds under the Tax Incentive for as long as it remains eligible and continues to incur eligible research and development expenditures. Although Equillium Australia believes that it has complied with all relevant conditions of eligibility under the program for all periods claimed, the ATO has the right to review Equillium Australia’s qualifying programs and related expenditures for a period of up to four years. Additionally, the period open for review is indefinite if the ATO suspects fraud. If such a review were to occur, the ATO may have different interpretations of certain eligibility requirements. If the ATO disagreed with Equillium Australia’s assessments and any related subsequent appeals, it could require adjustment to and potential repayment of current or previous years’ claims already received. If Equillium Australia was unable to demonstrate a reasonably arguable position taken on such claims, the ATO could also assess penalties and interest on potential adjustment amounts. The Company has not provided any allowance for any such potential adjustments, should they occur in the future. The estimated Tax Incentive refund amounts are recognized as a reduction to research and development expense when there is reasonable assurance that the Tax Incentive refund amounts will be received, the relevant expenditure has been incurred, and the amount can be reliably measured. During the three months ended June 30, 2024 and 2023, the Company recorded $ 0.4 million and $ 0.5 million, respectively, as a reduction to research and development expenses related to the Tax Incentive. During the six months ended June 30, 2024 and 2023, the Company recorded $ 1.4 million and $ 1.2 million, respectively, as a reduction to research and development expenses related to the Tax Incentive. The Company classifies its estimate for the Tax Incentive as prepaid expenses and other current assets on the accompanying condensed consolidated balance sheet. As of June 30, 2024 and December 31, 2023, the Company recorded $ 0.7 million and $ 2.1 million within prepaid and other current assets attributed to the Tax Incentive, respectively. Revenue Recognition The Company recognizes revenue in a manner that depicts the transfer of control of a product or a service to a customer and reflects the amount of the consideration the Company is entitled to receive in exchange for such product or service. In doing so, the Company follows a five-step approach: (i) identify the contract with a customer, (ii) identify the performance obligations in the contract, (iii) determine the transaction price, (iv) allocate the transaction price to the performance obligations, and (v) recognize revenue when (or as) the customer obtains control of the product or service. The Company considers the terms of a contract and all relevant facts and circumstances when applying the revenue recognition standard. The Company applies the revenue recognition standard, including the use of any practical expedients, consistently to contracts with similar characteristics and in similar circumstances. A customer is a party that has entered into a contract with the Company, where the purpose of the contract is to obtain a product or a service that is an output of the Company’s ordinary activities in exchange for consideration. To be considered a contract, (i) the contract must be approved (in writing, orally, or in accordance with other customary business practices), (ii) each party’s rights regarding the product or the service to be transferred can be identified, (iii) the payment terms for the product or the service to be transferred can be identified, (iv) the contract must have commercial substance (that is, the risk, timing or amount of future cash flows is expected to change as a result of the contract), and (v) it is probable that the Company will collect substantially all of the consideration to which it is entitled to receive in exchange for the transfer of the product or the service. A performance obligation is defined as a promise to transfer a product or a service to a customer. The Company identifies each promise to transfer a product or a service (or a bundle of products or services, or a series of products and services that are substantially the same and have the same pattern of transfer) that is distinct. A product or a service is distinct if both (i) the customer can benefit from the product or the service either on its own or together with other resources that are readily available to the customer and (ii) the Company’s promise to transfer the product or the service to the customer is separately identifiable from other promises in the contract. Each distinct promise to transfer a product or a service is a unit of accounting for revenue recognition. If a promise to transfer a product or a service is not separately identifiable from other promises in the contract, such promises should be combined into a single performance obligation. The transaction price is the amount of consideration the Company is entitled to receive in exchange for the transfer of control of a product or a service to a customer. To determine the transaction price, the Company considers the existence of any significant financing component, the effects of any variable elements, noncash considerations and consideration payable to the customer. If a significant financing component exists, the transaction price is adjusted for the time value of money. If an element of variability exists, the Company must estimate the consideration it expects to receive and uses that amount as the basis for recognizing revenue as the product or the service is transferred to the customer. There are two methods for determining the amount of variable consideration: (i) the expected value method, which is the sum of probability-weighted amounts in a range of possible consideration amounts, and (ii) the mostly likely amount method, which identifies the single most likely amount in a range of possible consideration amounts. If a contract has multiple performance obligations, the Company allocates the transaction price to each distinct performance obligation in an amount that reflects the consideration the Company is entitled to receive in exchange for satisfying each distinct performance obligation. For each distinct performance obligation, revenue is recognized when (or as) the Company transfers control of the product or the service applicable to such performance obligation. In those instances where the Company first receives consideration in advance of satisfying its performance obligation, the Company classifies such consideration as deferred revenue until (or as) the Company satisfies such performance obligation. In those instances where the Company first satisfies its performance obligation prior to its receipt of consideration, the consideration is recorded as accounts receivable. The Company expenses incremental costs of obtaining and fulfilling a contract as and when incurred if the expected amortization period of the asset that would be recognized is one year or less, or if the amount of the asset is immaterial. Otherwise, such costs are capitalized as co ntract assets if they are incremental to the contract and amortized to expense proportionate to revenue recognition of the underlying contract. Contract Assets The Company does not have material amounts of contract assets since revenue is recognized as control of goods is transferred or as services are performed. There are a small number of research and development services that may occur over a period of time, but that period of time is generally very short in duration. Any contract assets that may arise are recorded in accounts receivable in the Company’s condensed consolidated balance sheet net of an allowance for credit losses. The Company's contract assets include trade accounts receivables from the Ono Asset Purchase Agreement (see Note 8). Reimbursable costs that have not been invoiced as of the balance sheet date are recorded as unbilled accounts receivable. As of June 30, 2024 and December 31, 2023, the Company had unbilled accounts receivable totaling $ 5.9 million and $ 3.7 million, respectively, classified as accounts receivable on its condensed consolidated balance sheets. Contract Liabilities The Company’s contract liabilities consist of advance payments and deferred revenue. The Company classifies advance payments and deferred revenue as current or noncurrent based on the timing of when it expects to recognize revenue. Generally, all contract liabilities are expected to be recognized within one year and are included in deferred revenue in the Company’s condensed consolidated balance sheet. The noncurrent portion of deferred revenue is included and separately disclosed in the Company’s condensed consolidated balance sheet. Acquired In-Process Research and Dev elopment Expense The Company has acquired, and may continue to acquire, the rights to develop new product candidates. Payments to acquire a new product candidate, as well as future milestone payments associated with asset acquisitions in which contingent payments are resolved are immediately expensed as acquired in-process research and development provided that the product candidate has not achieved regulatory approval for marketing and, absent obtaining such approval, has no alternative future use. Research and Development Research and developm ent expenses include salaries and related overhead expenses, non-cash stock-based compensation expense, external research and development expenses incurred under arrangements with third parties, costs of services performed by consultants and contract research organizations, regulatory costs including those related to preparing and filing INDs with the FDA, pharmacovigilance costs related to drug safety monitoring and reporting, and external expenses related to CMC, formulation and device development, and supply of drug product. Research and development costs are expensed as incurred. Patent C osts The Company expenses all costs as incurred in connection with patent applications (including direct application fees, and the legal and consulting expenses rela ted to making such applications) and such costs are included in general and administrative expenses in the condensed consolidated statement of operations. Stock-Based Compensation The Company measures employee and non-employee stock-based awards, including stock options and stock purchase rights, at grant-date fair value and records compensation expense on a straight-line basis over the vesting period of the award. The Company uses the Black-Scholes option pricing model to value its stock option awards. Estimating the fair value of stock option awards requires management to apply judgment and make estimates of certain assumptions, including the volatility of the Company’s common stock, the expected term of the Company’s stock options, the expected dividend yield and the fair value of the Company’s common stock on the measurement date. As a result, if factors change and management uses different assumptions, stock-based compensation expense could be materially different for future awards. Incom e Taxes The Company accounts for income taxes under the asset and liability method, which requires the recognition of deferred tax assets and liabilities for the expected future tax consequences of events that have been included in the condensed consolidated financial statements. Under this method, deferred tax assets and liabilities are determined on the basis of the differences between the condensed consolidated financial statements and tax basis of assets and liabilities using enacted tax rates in effect for the year in which the differences are expected to reverse. The effect of a change in tax rates on deferred tax assets and liabilities is recognized in income in the period that includes the enactment date. The Company recognizes deferred tax assets to the extent that the Company believes these assets are more likely than not to be realized. In making such a determination, management considers all available positive and negative evidence, including future reversals of existing taxable temporary differences, projected future taxable income, tax-planning strategies, and results of recent operations. If management determines that the Company would be able to realize its deferred tax assets in the future in excess of their net recorded amount, management would make an adjustment to the deferred tax asset valuation allowance, which would reduce the provision for income taxes. Pursuant to the Internal Revenue Code of 1986, as amended (IRC), specifically Sections 382 and 383, the Company’s ability to use tax attribute carryforwards to offset future taxable income is limited if the Company experiences a cumulative change in ownership of more than 50% within a three-year testing period. The Company has not completed an ownership change analysis pursuant to IRC Section 382 subsequent to June 30, 2023 and may also experience ownership changes in the future as a result of subsequent shifts in stock ownership. If ownership changes within the meaning of IRC Section 382 are identified as having occurred, the amount of remaining tax attribute carryforwards available to offset future taxable income and income tax expense in future years may be significantly restricted or eliminated, including those acquired through Bioniz. Further, the Company’s deferred tax assets associated with such tax attributes could be significantly reduced or eliminated upon realization of an ownership change within the meaning of IRC Section 382. If eliminated, the related asset would be removed from the deferred tax asset schedule, with a corresponding reduction in the valuation allowance. Additionally, limitations on the utilization of the Company’s tax attribute carryforwards can increase the amount of taxable income and current income tax expense recognized. Due to the existence of the valuation allowance, ownership change limitations that are not significant may not impact the Company's effective tax rate. The Tax Cuts and Jobs Act of 2017 amended IRC Section 174 to eliminate the immediate expensing of research and experimental (R&E) expenditures for amounts paid or incurred in tax years beginning after December 31, 2021. The rules of IRC Section 174, as amended, require taxpayers to charge their R&E expenditures and software development costs (collectively, R&E expenditures) to a capital account. Capitalized costs are required to be amortized over five or fifteen years for research performed within the United States or foreign jurisdictions, respectively. The Company records uncertain tax positions on the basis of a two-step process whereby (1) management determines whether it is more likely than not that the tax positions will be sustained on the basis of the technical merits of the position and (2) for those tax positions that meet the more- likely-than-not recognition threshold, management recognizes the largest amount of tax benefit that is more than 50 percent likely to be realized upon ultimate settlement with the related tax authority. The Company recognizes interest and penalties related to unrecognized tax benefits within income tax expense. Any accrued interest and penalties are included within the related tax liability. Net Income (Loss) per Share Basic net income (loss) per share is calculated by dividing the net income (loss) by the weighted-average number of common shares outstanding for the period. Diluted net income (loss) per share is calculated by dividing the net income (loss) by the sum of the weighted average number of common shares outstanding and potentially dilutive common shares outstanding for the period. The Company’s potentially dilutive securities include outstanding options under the Company’s 2018 Equity Incentive Plan, 2024 Inducement Plan and outstanding warrants to purchase common stock. Potentially dilutive common shares are only included when their effect is dilutive. In loss periods, basic and diluted loss per share are identical since the effect of potentially dilutive securities is anti-dilutive and therefore excluded. Potentially dilutive common shares from options and warrants are determined using the average share price for each period under the treasury stock method. In addition, proceeds from exercises of options and warrants and the average amount of unrecognized compensation expenses are assumed to be used to repurchase shares. The following table presents the weighted-average number of common shares used to calculate basic and diluted net income (loss) per share: Three Months Ended Six Months Ended 2024 2023 2024 2023 Weighted-average number of common shares used in calculating basic net income (loss) per share 35,292,035 34,449,769 35,273,394 34,432,057 Weighted average number of common shares used in calculating diluted net income (loss) per share 36,589,774 34,449,769 35,273,394 34,432,057 Anti-dilutive shares: Common stock options 7,886,188 7,317,199 9,183,927 7,317,199 Common stock warrants 1,366,141 1,366,141 1,366,141 1,366,141 Potentially dilutive shares excluded from calculation due to antidilutive effect 9,252,329 8,683,340 10,550,068 8,683,340

Fair Value of Financial Instrum

Fair Value of Financial Instruments	6 Months Ended
	Jun. 30, 2024
Fair Value Disclosures [Abstract]
Fair Value of Financial Instruments	3. Fair Value of Financial Instruments The following tables summarize the Company’s assets that require fair value measurements on a recurring basis and their respective input levels based on the fair value hierarchy (in thousands): Fair Value Measurements Using Quoted Prices in Significant Significant Active Markets Other Unobservable June 30, for Identical Observable Inputs 2024 Assets (Level 1) Inputs (Level 2) (Level 3) Short-term investments: U.S. treasury securities $ 22,242 $ 22,242 $ - $ - Total $ 22,242 $ 22,242 $ - $ - Fair Value Measurements Using Quoted Prices in Significant Significant Active Markets Other Unobservable December 31, for Identical Observable Inputs 2023 Assets (Level 1) Inputs (Level 2) (Level 3) Short-term investments: U.S. treasury securities $ 17,650 $ 17,650 $ - $ - Total $ 17,650 $ 17,650 $ - $ - U.S. treasury securities are valued using Level 1 inputs. Level 1 securities are valued at unadjusted quoted prices in active markets that are observable at the measurement date for identical, unrestricted assets or liabilities. Fair values determined by Level 2 inputs, which utilize data points that are observable such as quoted prices, interest rates and yield curves, require the exercise of judgment and use of estimates, that if changed, could significantly affect the Company’s financial position and results of operations. Investments in agency securities are valued using Level 2 inputs. Level 2 securities are initially valued at the transaction price and subsequently valued and reported utilizing inputs other than quoted prices that are observable either directly or indirectly, such as quotes from third-party pricing vendors. The carrying amounts of the Company’s financial instruments, including cash and cash equivalents, prepaid and other current assets, accounts payable, and accrued liabilities, approximate fair value due to their short maturities. None of the Company’s non-financial assets or liabilities are recorded at fair value on a non-recurring basis. The Company did no t hold any Level 1, 2 or 3 financial liabilities that are recorded at fair value on a recurring basis as of June 30, 2024 or December 31, 2023.

Certain Financial Statement Cap

Certain Financial Statement Caption Information	6 Months Ended
	Jun. 30, 2024
Certain Financial Statement Caption Information [Abstract]
Certain Financial Statement Caption Information	4. Certain Financial Statement Caption Information Short-Term Investments The following table summarizes the Company’s short-term investments (in thousands): Maturity Amortized Unrealized Unrealized Estimated (in years) Cost Gains Losses Fair Value June 30, 2024 U.S. treasury securities 1 or less $ 22,252 - $ ( 10 ) $ 22,242 Total $ 22,252 $ - $ ( 10 ) $ 22,242 December 31, 2023 U.S. treasury securities 1 or less $ 17,632 18 - $ 17,650 Total $ 17,632 $ 18 $ - $ 17,650 All of the Company’s available-for-sale securities are available to the Company for use in its current operations. As a result, the Company categorizes all of these securities as current assets even though the stated maturity of some individual securities may be one year or more beyond the balance sheet date. All of the Company’s securities have a maturity within two years of the balance sheet date. There were no impairments considered other-than-temporary during the periods presented, as it is management’s intention and ability to hold the securities until a recovery of the cost basis or recovery of fair value. Unrealized gains and losses are included in accumulated other comprehensive income in the Company's condensed consolidated balance sheets. Accrued Expenses Accrued expenses consisted of the following (in thousands): June 30, December 31, 2024 2023 Accrued payroll and other employee benefits $ 1,991 $ 3,054 Clinical development 3,436 1,850 Biocon and its subsidiaries chemistry, manufacturing and controls services - related party 363 719 Biocon clinical development related to ulcerative colitis study - related party 272 415 Non-clinical research 441 228 Other accruals 400 431 Total accrued expenses $ 6,903 $ 6,697

Acquisition

Acquisition	6 Months Ended
	Jun. 30, 2024
Business Combination, Asset Acquisition, and Joint Venture Formation [Abstract]
Acquisition	5. Acquisition On February 14, 2022, the Company entered into an Agreement and Plan of Merger with Project JetFuel Merger Sub, Inc., a Delaware corporation and wholly owned subsidiary of the Company (Merger Sub), Bioniz and Kevin Green, solely in his capacity as representative of the securityholders of Bioniz (the Securityholders’ Representative). As consideration for the acquisition of Bioniz, the Company agreed to (a) issue up to an aggregate of 5,699,492 shares of the Company’s common stock (Merger Shares), and (b) make contingent payments up to an aggregate of $ 57.5 million based on the achievement of certain regulatory events for the Bioniz product candidates commencing on first U.S. approval, and up to an aggregate of $ 250 million based on the achievement of certain commercialization events for product candidate BNZ-1 (now referred to as EQ101) as set forth in the Merger Agreement. The Merger Shares may be adjusted downward after the closing, pursuant to procedures set forth in the Merger Agreement, including with respect to indemnification claims and in connection with the finalization of transaction expenses, debt, net exercise taxes and working capital amounts at closing. At closing, the Company delivered to the transfer agent 4,820,230 shares of its common stock for issuance to former stockholders of Bioniz per the terms of the Merger Agreement. Up to an additional 879,252 shares of the Company's common stock, pending any adjustments per the terms of the Merger Agreement, were to be issued to former stockholders of Bioniz 18 months after closing. On August 14, 2023, the Company issued 849,133 shares of the Company's common stock to the former stockholders of Bioniz, net of final adjustments per the terms of the Merger Agreement. The fair value of the fewer shares issued was not deemed material and, therefore, there was no adjustment to in-process research and development recorded on the condensed consolidated statement of operations and comprehensive loss for the year ended December 31, 2023, or to additional paid-in capital on the condensed consolidated balance sheet as of December 31, 2023. The acquisition of Bioniz expanded the Company's pipeline of novel immunomodulatory drug candidates, adding a first-in-class clinical-stage asset, BNZ-1, now referred to as EQ101, and a proprietary product discovery platform. The Company determined the acquisition constituted an acquisition of assets instead of a business combination as substantially all of the fair value of the gross assets acquired was concentrated in a group of similar identifiable assets, and therefore, the acquisition was not considered a business. As the Company is recording the transaction as an asset acquisition under ASC 805, the contingent payments will be recognized upon achievement and at that time will be expensed to in-process research and development.

Notes Payable

Notes Payable	6 Months Ended
	Jun. 30, 2024
Debt Disclosure [Abstract]
Notes Payable	6. Notes Payable On September 30, 2019 (the Effective Date), the Company entered into a Loan and Security Agreement (the Loan Agreement) with two lenders (the Lenders) pursuant to which the Company borrowed $ 10.0 million from the Lenders (the Term Loan), which represented the maximum amount the Company was permitted to borrow under the terms of the Loan Agreement. The Term Loan was set to mature on June 1, 2024 (the Maturity Date) and was initially being repaid through interest-only payments, which originally extended through June 30, 2021, followed by 36 equal monthly payments of principal and interest. The Term Loan interest was at a floating per annum rate equal to the greater of (i) 8.25 % and (ii) the sum of (a) the prime rate reported in The Wall Street Journal on the last business day of the month that immediately preceded the month in which the interest was being accrued, plus (b) 3.00 %. On April 23, 2021, the Loan Agreement was amended to (i) change the final payment percentage from 4.5 % to 5.0 % and (ii) extend the interest-only payment period based on achieving the following milestones: (a) the Company achieving positive data in the Company's Phase 1b acute graft-versus-host disease (aGVHD) trial of itolizumab (EQ001) supporting a formal decision to advance into Phase 2 or Phase 3 development, and as confirmed by the Company's Board of Directors in written board minutes (the Interest-Only Extension Milestone) and (b) the Company initiating a pivotal Phase 3 aGVHD trial (the Interest-Only Extension II Milestone). In May 2021, the Company achieved the Interest-Only Extension Milestone, and in March 2022, the Company obtained confirmation from the Lenders that the Interest-Only Extension II Milestone had been achieved, which extended the interest-only payments through September 30, 2022, followed by 24 equal monthly principal payments and interest. In February 2022, the Company entered into a Third Amendment to the Loan Agreement (the Third Amendment) which added Bioniz as a secured party to the loan. Under the Loan Agreement, the Company was required to make a final payment of 5.00 % of the original principal amount of the Term Loan drawn payable on the earlier of (i) the Maturity Date, (ii) the acceleration of the Term Loan in the event of a default, or (iii) the prepayment of the Term Loan (the Final Payment). The Company could prepay all, but not less than all, of the Term Loan upon 30 days’ advance written notice to the lender, provided that the Company was obligated to pay a prepayment fee equal to (i) 3.00 % of the principal amount of the Term Loan prepaid on or before the first anniversary of the applicable funding date, (ii) 2.00 % of the principal amount of the Term Loan prepaid between the first and second anniversary of the funding date, and (iii) 1.00 % of the principal amount of the Term Loan prepaid thereafter, and prior to the Maturity Date (each, a Prepayment Fee). In connection with entering into the Loan Agreement, the Company issued to the Lenders warrants exercisable for 80,428 shares of the Company’s common stock (the Warrants). The Warrants are exercisable in whole or in part, immediately, and have a per share exercise price of $ 3.73 , which was the closing price of the Company’s common stock reported on the Nasdaq Global Market (prior to the Company’s transfer to the Nasdaq Capital Market on September 15, 2023) on the day prior to the Effective Date. The Warrants will terminate on the earlier of September 30, 2029 or the closing of certain merger or consolidation transactions. On May 25, 2023, the Company prepaid in full all amounts owed under, and terminated, the Loan Agreement. In connection with the prepayment and termination of the Loan Agreement, the Company paid a total of approximately $ 6.8 million, which consisted of (i) the remaining principal amount and interest outstanding of approximately $ 6.2 million as of the date of the repayment, (ii) a Prepayment Fee of approximately $ 62,000 , (iii) the Final Payment of approximately $ 0.5 million, and (iv) the remainder for transaction expenses. Following the termination of the Loan Agreement, the Company had no further obligations.

Leases

Leases	6 Months Ended
	Jun. 30, 2024
Leases [Abstract]
Leases	7. Leases The Company’s leases relate primarily to office and laboratory facilities located in La Jolla, California and previously in South San Francisco, California. The Company’s lease of office space in South San Francisco expired in February 2023 and the Company did not renew that lease. The Company’s lease of laboratory space in La Jolla expires in February 2025 , and the Company's leases of office space in La Jolla expire in 2027 . The terms of the Company’s non-cancelable operating lease arrangements typically contain fixed lease payments which increase over the term of the lease at fixed rates, and include rent holidays and provide for additional renewal periods. Lease expense is recognized over the term of the lease on a straight-line basis. All of the Company’s leases are classified as operating leases. The Company has determined that periods covered by options to extend the Company’s leases are excluded from the lease term as the Company is not reasonably certain the Company will exercise such options. Operating lease expense, including expenses related to short-term leases, was $ 0.1 million and $ 0.3 million for the three and six months ended June 30, 2024, respectively, and $ 0.1 million and $ 0.3 million for the three and six months ended June 30, 2023, respectively. The Company records its right-of-use (ROU) assets within other assets (long term) and its operating lease liabilities within other current and long-term liabilities. Additional information related to the Company’s leases as of and for the six months ended June 30, 2024, is as follows (in thousands, except lease term and discount rate): June 30, 2024 Balance sheet information Right-of-use assets $ 592 Lease liabilities, current $ 350 Lease liabilities, non-current 259 Total lease liabilities $ 609 Other information Weighted average remaining lease term 1.96 Weighted average discount rate 8.25 % Supplemental cash flow information Operating cash flows from operating leases $ 245 Right-of-use assets obtained in exchange for lease obligations $ — Maturities of lease liabilities as of June 30, 2024 were as follows (in thousands): Year ending December 31, 2024 (remaining six months) $ 247 2025 219 2026 169 2027 28 Total undiscounted lease payments 663 Less: imputed interest ( 54 ) Total lease liabilities $ 609 As of June 30, 2024, the Company does not have any leases that have not yet commenced that create significant rights and obligations.

Partnerships

Partnerships	6 Months Ended
	Jun. 30, 2024
Collaboration And License Agreement [Abstract]
Partnerships	8. Partnerships Asset Purchase Agreement with Ono Pharmaceutical Co., Ltd. On December 5, 2022, the Company and Ono, a Japan kabushiki kaisha, entered into an Asset Purchase Agreement pursuant to which the Company granted Ono the exclusive right, but not the obligation, to acquire the Company’s rights to itolizumab (the Option). These rights include all therapeutic indications and the rights to commercialize itolizumab in the United States, Canada, Australia, and New Zealand. In exchange for the Option, Ono paid the Company a one-time, upfront payment of an amount equal to JPY 3.5 billion, or $ 26.4 million. If Ono exercises the Option, Ono will pay the Company a one-time payment of an amount equal to JPY 5.0 billion, or approximately $ 35.0 million based on the currency exchange rate quoted by MUFG Bank, Ltd. on August 5, 2024. The Company is also eligible to receive up to $ 101.4 million upon the achievement of certain clinical, regulatory and commercialization milestones as well as continued reimbursement of itolizumab-related expenses and a markup on full time equivalent costs. The Company is responsible for conducting all research and development of itolizumab, which is being funded by Ono on a quarterly basis from July 1, 2022, through the option period. Unless terminated early, the option period will expire 90 days following the delivery of topline data from the EQUALISE clinical study in lupus nephritis (LN) and the results of the interim analysis from the Phase 3 EQUATOR clinical study in aGVHD. In April 2024, the Company delivered topline data from the EQUALISE clinical study in LN to Ono, and on August 1, 2024 we delivered the results of the interim analysis from the Phase 3 EQUATOR clinical study in aGVHD to Ono, which results in the expiration of Ono's option period on October 30, 2024. The Asset Purchase Agreement can be terminated at any time by Ono upon written notice, provided that in limited circumstances Ono will be obligated to continue to reimburse the Company for research and development costs and expenses of itolizumab for a certain period of time following such termination. If Ono does not timely exercise its Option, the Asset Purchase Agreement and the Option will automatically terminate. The Asset Purchase Agreement also contains customary termination rights for both parties for material breach and an outside date (subject to limited adjustments) that permits either party to terminate the Asset Purchase Agreement if the closing has not occurred by December 31, 2025. The Asset Purchase Agreement contains customary representations and warranties with respect to both the Company and Ono. Additionally, the Company is subject to customary obligations and covenants, including affirmative and negative operating covenants on the Company with respect to its business as it applies to the development and exploitation of itolizumab, exclusivity obligations that prohibit the Company, except in limited circumstances, including in connection with the sale of the Company, from pursuing a direct or indirect sale, license or other disposition of all or any portion of the Company's itolizumab program or any of the assets to be purchased pursuant to the Asset Purchase Agreement and indemnification obligations, which, except in limited circumstances, are subject to customary caps and deductibles. The Company applied ASC 808, Collaborative Arrangements, to the Asset Purchase Agreement and determined that the agreement is applicable to such guidance. The Company concluded that Ono represented a customer and applied relevant guidance from ASC 606, Revenue Recognition , (ASC 606) to evaluate the appropriate accounting for the Asset Purchase Agreement. In accordance with this guidance, the Company identified its performance obligations, including its grant of a license to Ono to certain of its intellectual property subject to certain conditions and the conduct of research and development services. The Company determined that its grant of a license to Ono to certain of its intellectual property subject to certain conditions was not distinct from other performance obligations because such grant is dependent on the conduct and results of the research and development services. Accordingly, the Company determined that all performance obligations should be accounted for as one combined performance obligation, and that the combined performance obligation is transferred over the expected term of the conduct of the research and development services. The Company also assessed, in connection with the upfront and non-creditable payment of JPY 3.5 billion or $ 25.8 million, invoiced on December 5, 2022, that there was not a significant financing component in the Asset Purchase Agreement. The Company received payment of $ 26.4 million related to this upfront payment in December 2022 which included a foreign currency realized gain of $ 0.6 million as the initial invoice for the upfront payment was denominated in JPY. The Company also assessed the effects of any variable elements under the Asset Purchase Agreement. Such assessment evaluated, among other things, the likelihood of receiving (i) option fees and (ii) various clinical, regulatory and commercial milestone payments. Based on its assessment, the Company concluded that, based on the likelihood of these variable components occurring, there was not a significant variable element included in the transaction price. Accordingly, the Company has not assigned a transaction price to any option fees or milestone payments under the Asset Purchase Agreement given the substantial uncertainty related to their achievement. In accordance with ASC 606, the Company determined that the initial transaction price under the Asset Purchase Agreement equals $ 102.6 million, consisting of the upfront and non-creditable payment of $ 25.8 million and the aggregate estimated research and development funding of $ 76.8 million over the estimated option period. The upfront payment of $ 25.8 million was recorded as deferred revenue and is being recognized as revenue over time in conjunction with the Company’s conduct of research and development services as the research and development services are the primary component of the combined performance obligations. Revenue associated with the upfront payment will be recognized based on actual research and development costs incurred as a percentage of the estimated total research and development costs to be incurred over the expected term of the option period. Reimbursable research and development costs will be recognized as revenue as incurred. The Company’s policy is to periodically review the estimated aggregate research and development funding over the estimated option period when facts and circumstances change. The Company’s review in the second quarter of 2024 resulted in a revised estimate of the aggregate research and development funding over the estimated option period from $ 76.8 million to $ 70.8 million and an update to the transaction price from $ 102.6 million to $ 96.6 million. The lower estimate of the aggregate research and development funding is primarily driven by a shortening of the option period as a result of delivery of the interim analysis of the EQUATOR clinical study to Ono earlier than previously anticipated. The effect of this change in estimate was to increase revenue related to the amortization of the upfront payment in each of the three and six-month periods ended June 30, 2024 by $ 1.3 million. The Company recognized revenue of $ 13.9 million and $ 24.5 million under the Asset Purchase Agreement during the three and six months ended June 30, 2024, respectively. The Company recognized revenue of $ 9.1 million and $ 18.0 million under the Asset Purchase Agreement during the three and six months ended June 30, 2023, respectively. Such revenue was comprised of $ 9.2 million and $ 17.2 million associated with development funding for the three and six months ended June 30, 2024, respectively, and $ 4.7 million and $ 7.3 million associated with the amortization of the upfront payment for the three and six months ended June 30, 2024, respectively. As of June 30, 2024, aggregate deferred revenue related to the Asset Purchase Agreement was $ 8.4 million, which was classified as short-term on the condensed consolidated balance sheet. As of June 30, 2024, the Company has received $ 53.1 million in cash related to aggregate development funding from Ono. Biocon Collaboration and License Agreement In May 2017, the Company entered into a collaboration and license agreement (which was amended in September 2018, April 2019, December 2019, April 2021 and November 2022), clinical supply agreement, investor rights agreement, and common stock purchase agreement (collectively License Agreements) with Biocon SA (subsequently assigned to Biocon Limited, or together, Biocon). Pursuant to the License Agreements, Biocon granted the Company an exclusive license to develop, make, have made, use, sell, have sold, offer for sale, import and otherwise exploit itolizumab and any pharmaceutical composition or preparation containing or comprising itolizumab that uses Biocon technology or Biocon know-how (collectively a Biocon Product) in the United States, Canada, Australia and New Zealand (collectively Equillium Territory). The Company also has the right to sublicense through multiple tiers to third parties, provided such sublicenses comply with the terms of the License Agreements and the Company provides Biocon a copy of each sublicense agreement within 30 days of execution. If the Company grants a third party a sublicense of its rights to develop and commercialize Biocon Products in Australia or New Zealand, the Company will be required to pay Biocon a high double-digit percentage of any upfront payment the Company receives from such sublicensee for such sublicense, as well as a high double-digit percentage of any additional payments the Company receives from such sublicensee for such sublicense, including but not limited to royalty payments on net sales of Biocon Products by such sublicensee. Under the License Agreements, the Company granted back to Biocon a license to use its technology and know-how related to itolizumab and Biocon Products in certain countries outside of the Equillium Territory. Pursuant to the License Agreements, Biocon agreed to be the Company’s exclusive supplier of itolizumab clinical drug product. Biocon will provide clinical drug product at no cost for up to three concurrent orphan indications until the Company’s first U.S. regulatory approval and all other clinical drug product at Biocon’s cost. In consideration of the rights granted to the Company by Biocon, the Company issued Biocon a total of 2,316,134 shares of its common stock. In addition, the Company is obligated to pay Biocon up to an aggregate of $ 30 million in regulatory milestone payments upon the achievement of certain regulatory approvals and up to an aggregate of $ 565 million in sales milestone payments upon the achievement of first commercial sale of product and specified levels of product sales. The Company is also required to pay royalties on tiers of aggregate annual net sales of Biocon Products by the Company, the Company's affiliates and the Company's sublicensees in the United States and Canada at percentages from the mid-single digits to sub-teen double-digits and on tiers of aggregate annual net sales of Biocon Products by the Company and the Company's affiliates (but not the Company's sublicensees) in Australia and New Zealand, in each case, subject to adjustments in certain circumstances. Biocon is also required to pay the Company royalties at comparable percentages for sales of itolizumab (EQ001) outside of the Equillium Territory if the approvals in such geographies included or referenced the Company’s data including data from certain of the Company’s clinical studies, subject to adjustments in certain circumstances. Should Ono exercise its option to acquire the Company's rights to itolizumab (EQ001), as described below, the aforementioned milestone payments and royalties potentially owed to Biocon would become Ono’s responsibility, and the potential royalties on sales of itolizumab outside of the Equillium Territory would be become Ono’s right. Under the License Agreements, net sales are calculated on a country-by-country basis and are subject to adjustments, including whether the Biocon Product is sold in the form of a combination product. As of June 30, 2024, the Company has not made or received payments in connection with the milestones or royalties within the agreement.

Stockholders' Equity

Stockholders' Equity	6 Months Ended
	Jun. 30, 2024
Equity [Abstract]
Stockholders’ Equity	9. Stockholders’ Equity As of June 30, 2024 , the Company’s authorized capital stock consisted of 200,000,000 shares of common stock, par value $ 0.0001 per share, and 10,000,000 shares of preferred stock, par value $ 0.0001 per share. The Company had 35,424,388 and 35,254,752 shares of common stock outstanding as of June 30, 2024 and December 31, 2023, respectively. 2023 ATM Facility In October 2023, the Company entered into an at-the-market facility with Jefferies LLC (Jefferies), under which the Company may offer and sell shares of its common stock having an aggregate offering price of up to $ 21.95 million from time to time through Jefferies acting as the Company’s sales agent (the 2023 ATM Facility). As of the filing of this Quarterly Report on Form 10-Q, the Company has no t sold any shares under the 2023 ATM Facility. Authorization of Stock Repurchase Program In July 2023, the Company’s board of directors authorized a stock repurchase program pursuant to which the Company may repurchase up to $ 7.5 million of shares of its common stock through December 31, 2024. Under the program, the Company may repurchase shares of common stock during the term of the program through open market transactions or such other transactions as the Company’s board of directors or designated committee thereof may approve from time to time. The timing and amount of repurchases, if any, will depend on a variety of factors, including the price of the Company’s common stock, alternative investment opportunities, the Company’s cash resources, restrictions under any of the Company’s agreements, corporate and regulatory requirements and market conditions. As of June 30, 2024, the Company had repurchased 298,385 shares of its common stock under the stock repurchase program for a total of $ 0.3 million. There have been no repurchases of common stock under the stock repurchase program during the six months ended June 30, 2024 or since June 30, 2024 and through the date of the filing of this Quarterly Report on Form 10-Q. The Company expects to fund any future repurchase of shares of its common stock, if any, under the program with existing cash and cash equivalents. 2024 Inducement Plan On March 6, 2024, upon the recommendation of the Compensation Committee of the Company’s board of directors, the Company’s board of directors adopted and approved the Company’s 2024 Inducement Plan (the Inducement Plan) to reserve 1,500,000 shares of the Company's common stock to be used exclusively for grants of equity awards to individuals that were not previously employees or directors of the Company (or who are returning to employment following a bona fide period of non-employment), as an inducement material to the individual’s entry into employment with the Company, pursuant to Nasdaq Listing Rule 5635(c)(4). The Inducement Plan was adopted and approved without stockholder approval pursuant to Nasdaq Listing Rule 5635(c)(4). In addition, the Company's board of directors adopted and approved forms of Stock Option Grant Notice, Option Agreement and Notice of Exercise for use with the Inducement Plan. The terms and conditions of the Inducement Plan are substantially similar to the Company’s stockholder-approved 2018 Equity Incentive Plan (the 2018 Plan). As of June 30, 2024, there have been options to purchase 17,200 shares of the Company’s common stock granted from the Inducement Plan. These options were granted during the three months ended June 30, 2024. Repricing of Outstanding Options On August 7, 2023, the Company’s board of directors approved an option repricing, which was effective on August 14, 2023 (the Effective Date). The repricing applies to outstanding options to purchase shares of the Company’s common stock that, as of the Effective Date, were held by the Company’s employees, officers and certain non-employee directors (the Outstanding Options), to the extent such Outstanding Options have an exercise price in excess of the closing trading price of the Company’s common stock on the Effective Date, and were granted under the Company’s 2017 Equity Incentive Plan or 2018 Plan. As of the Effective Date, 6,628,589 of the Outstanding Options were repriced such that the exercise price per share for such Outstanding Options was reduced to the closing trading price of the Company’s common stock on the Effective Date, except that a premium exercise price will apply for certain exercises, as further described below. The Outstanding Options that were repriced on the Effective Date (the Repriced Options) included the Outstanding Options held by the Company’s executive officers and certain non-employee directors. If a Repriced Option is exercised prior to the Retention Period End Date (as defined below), or the optionholder’s employment or service terminates under certain circumstances prior to the Retention Period End Date, the optionholder will be required to pay a premium price equivalent to the original exercise price per share of the Repriced Options. The “Retention Period End Date” means the earliest of (i) the date 18 months following the Effective Date, (ii) a Change in Control (as defined in the 2018 Plan), and (iii) the optionholder’s termination of Continuous Service (as defined in the 2018 Plan) as a result of death, disability or certain other not for Cause (as defined in the 2018 Plan) terminations. In addition to the amendment to the exercise prices of the Repriced Options, any Repriced Options that were previously Incentive Stock Options were amended to become Nonstatutory Stock Options (each as defined in the 2018 Plan). There were no changes to the number of shares, the vesting schedule or the expiration date of the Repriced Options. The effect of the repricing resulted in a total incremental non-cash stock-based compensation expense of $ 1.3 million, which was calculated using the Black-Scholes option-pricing model, of which $ 0.8 million of the incremental non-cash stock-based compensation expense is associated with vested Repriced Options and will be recognized on a straight-line basis through the Retention Period End Date. The remaining $ 0.5 million of the incremental non-cash stock-based compensation expense is associated with unvested Repriced Options and will be recognized as follows: (a) if the Retention Period is greater than the remaining original vesting period of the Repriced Option, the incremental cost will be amortized on a straight-line basis through the Retention Period End Date or (b) if the Retention Period is less than the remaining original vesting term of the Repriced Option, the incremental cost will be amortized on a straight-line basis over the remaining original vesting period. During the three and six months ended June 30, 2024, the Company recognized incremental stock-based compensation expense totaling $ 0.2 million and $ 0.4 million, respectively, associated with the repricing which is included in general and administrative and research and development expense on the condensed consolidated statement of operations and comprehensive loss. Stock Options The following table summarizes stock option activity during the six months ended June 30, 2024: Outstanding Options Weighted- Weighted Aggregate (a) Balances as of December 31, 2023 7,031,075 $ 0.90 Granted 2,210,700 $ 0.79 Exercised - $ - Forfeitures and cancellations ( 57,848 ) $ 0.76 Balances as of June 30, 2024 9,183,927 $ 0.87 7.61 $ 19 Options exercisable as of June 30, 2024 4,813,600 $ 0.96 6.51 $ 8 (a) Aggregate intrinsic value in this table was calculated as the positive difference, if any, between the closing price per share of the Company’s common stock on June 28, 2024 of $ 0.69 and the price of the underlying options. At June 30, 2024, unamortized stock compensation for stock options was $ 4.7 million, with a weighted-average recognition period of 2.71 years. Stock-Based Compensation Expense The non-cash stock-based compensation expense for all stock awards, net of forfeitures recognized as they occur, that was recognized in the condensed consolidated statements of operations is as follows (in thousands): Three Months Ended Six Months Ended 2024 2023 2024 2023 Research and development $ 368 $ 377 $ 738 $ 787 General and administrative 584 557 1,186 1,185 Total $ 952 $ 934 $ 1,924 $ 1,972 Common Stock Reserved for Future Issuance Common stock reserved for future issuance is as follows: June 30, December 31, 2024 2023 Stock options issued and outstanding 9,183,927 7,031,075 Warrants for common stock 1,366,141 1,366,141 Awards available under the 2018 Equity Incentive Plan 203,549 576,464 Awards available under the 2024 Inducement Plan 1,482,800 - Employee stock purchase plan 1,153,022 979,383 Total 13,389,439 9,953,063

Income Taxes

Income Taxes	6 Months Ended
	Jun. 30, 2024
Income Tax Disclosure [Abstract]
Income Taxes	10. Income Taxes The Company is subject to income tax in the United States (U.S.) as well as other tax jurisdictions in which it conducts business. Earnings from non-U.S. activities are subject to local country income tax. The Company does not provide for U.S. deferred income taxes on the undistributed earnings of its foreign subsidiaries as such earnings are reinvested indefinitely. The Company’s tax provision for interim periods is determined using an estimate of its annual effective tax rate, adjusted for discrete items arising in that quarter. In each quarter, the Company updates its estimate of the annual effective tax rate, and if the estimated annual tax rate changes, the Company makes a cumulative adjustment in that quarter. The Company’s quarterly tax provision, and its quarterly estimate of its annual effective tax rate, are subject to significant volatility due to several factors, including the Company’s ability to accurately predict its pre-tax income and loss in multiple jurisdictions. There was no income tax expense recorded for the three and six-month periods ended June 30, 2024. Income tax expense was $ 8,000 and $ 0.1 million for the three and six months ended June 30, 2023, respectively. The Company’s 2023 income tax expense was primarily attributable to domestic cash tax expense resulting from differences between book and tax treatment of certain items. The Company does not record a deferred tax provision as there is a full valuation allowance offsetting the Company’s net deferred tax assets.

Related Party Transactions

Related Party Transactions	6 Months Ended
	Jun. 30, 2024
Related Party Transactions [Abstract]
Related Party Transactions	11. Related Party Transactions On April 7, 2022, the Company entered into an agreement with Biocon, who is a holder of more than 5% of the Company’s common stock, to collaborate on and co-fund a Phase 2 clinical study of itolizumab in subjects with ulcerative colitis that is being conducted by Biocon in India. The Company expects its share of the total clinical study costs will be approximately $ 1.5 million. During each of the three-month periods ended June 30, 2024 and 2023, the Company recognized $ 0.2 million and $ 0.1 million, respectively, of research and development expense related to its portion of the total clinical study costs. During each of the six-month periods ended June 30, 2024 and 2023, the Company recognized $ 0.4 million and $ 0.2 million, respectively, of research and development expense related to its portion of the total clinical study costs. As of June 30, 2024 and December 31, 2023, the Company had accrued expenses totaling $ 0.3 million and $ 0.4 million, respectively, and $ 0.3 million and no amounts invoiced, respectively, by and payable to Biocon related to the Company’s portion of the total clinical study costs. In February 2020, the Company entered into a master services agreement with Syngene International Limited (Syngene), a wholly-owned subsidiary of Biocon, for CMC services associated with itolizumab development (the Syngene MSA). In July 2023, the Company issued a signed work order under the Syngene MSA totaling $ 5.4 million for CMC activities related to the development of a pre-filled syringe product presentation for itolizumab. Of the total work order value, $ 0.7 million is a firm commitment as of June 30, 2024. In addition, the Company is working with Biocon on several CMC projects in preparation for a potential BLA filing related to itolizumab and has entered into several purchase orders totaling approximately $ 6.1 million to support these CMC projects. During the three and six months ended June 30, 2024, the Company recognized research and development expenses totaling $ 1.1 million and $ 2.1 million, respectively, related to these CMC agreements. During the three and six months ended June 30, 2023, there were no material research and development expenses recognized related to these CMC agreements. As of June 30, 2024 and December 31, 2023, the Company had accrued expenses totaling $ 0.4 million and $ 0.7 million, respectively, and $ 1.2 million and an immaterial amount, respectively, was invoiced by and payable to Biocon and Syngene. Aforementioned expenses associated with work performed by Biocon or its affiliates related to itolizumab development during the Ono option period are reimbursed by Ono pursuant to the terms of the Asset Purchase Agreement. The Company classifies its accruals related to these activities as accrued expenses on the accompanying condensed consolidated balance sheets. The Company classifies amounts invoiced by and payable to Biocon and Syngene as accounts payable on the accompanying condensed consolidated balance sheets.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 2024
Accounting Policies [Abstract]
Recently Issued and Adopted Accounting Pronouncements	Recently Issued and Adopted Accounting Pronouncements In October 2021, the FASB issued ASU 2021-08 , Business Combinations (Topic 805): Accounting for Contract Assets and Contract Liabilities from Contracts with Customers, which requires an acquirer to recognize and measure contract assets and liabilities acquired in a business combination in accordance with Revenue from Contracts with Customers (Topic 606) rather than adjust them to fair value at the acquisition date. This update is effective beginning with the Company’s 2024 fiscal year annual reporting period. The Company adopted ASU 2021-08 on January 1, 2024 on a prospective basis. The adoption of this standard did no t have a material impact on the Company’s condensed consolidated financial statements. In November 2023, the FASB issued ASU 2023-07 , Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures, which updates reportable segment disclosure requirements primarily through enhanced disclosures about significant segment expenses. The amendments are effective for fiscal years beginning after December 15, 2023, and for interim periods within fiscal years beginning after December 15, 2024. Early adoption is permitted. The amendments should be applied retrospectively to all prior periods presented in the financial statements. The Company is currently assessing the impact this standard will have on the Company’s condensed consolidated financial statements. In December 2023, the FASB issued ASU 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures. ASU 2023-09 requires annual disclosures of specific categories in the rate reconciliation, additional information for reconciling items that meet a quantitative threshold and a disaggregation of income taxes paid, net of refunds. ASU 2023-09 also eliminates certain existing disclosure requirements related to uncertain tax positions and unrecognized deferred tax liabilities. ASU 2023-09 is effective for the Company beginning with the Company's Annual Report on Form 10-K for the year ending December 31, 2025. Early adoption is permitted. ASU 2023-09 should be applied prospectively. Retrospective adoption is permitted. The Company is currently assessing the impact this standard will have on the Company’s condensed consolidated financial statements. No other new accounting pronouncements or legislation issued or effective as of June 30, 2024 have had, or are expected to have, a material impact on the Company’s condensed consolidated financial statements.
Use of Estimates	Use of Estimates The preparation of the Company’s condensed consolidated financial statements requires the Company to make estimates and assumptions that impact the reported amounts of assets, liabilities and expenses and the disclosure of contingent assets and liabilities in the condensed consolidated financial statements and accompanying notes. Significant estimates in the Company’s condensed consolidated financial statements relate to accrued research and development expense, expected refunds from the Australian Taxation Office for eligible research and development activities, revenue recognition and the valuation of equity awards. Management evaluates its estimates on an ongoing basis. Although estimates are based on the Company’s historical experience, knowledge of current events, and actions it may undertake in the future, actual results may ultimately materially differ from these estimates and assumptions.
Concentration of Credit Risk and Off-Balance Sheet Risk	Concentration of Credit Risk and Off-Balance Sheet Ris k Financial instruments which potentially subject the Company to significant concentration of credit risk consist of cash and cash equivalents and short-term investments. The Company maintains deposits in federally insured financial institutions in which the majority of deposits are in excess of federally insured limits. The Company has not experienced any losses in such accounts, and management believes that the Company is not exposed to significant credit risk due to the financial position of the depository institutions in which those deposits are held. The Company’s investment policy includes guidelines for the quality of the related institutions and financial instruments and defines allowable investments that the Company may invest in, which the Company believes minimizes the exposure to concentration of credit risk.
Comprehensive Loss	Comprehensive Loss The Company is required to report all components of comprehensive loss, including net loss, in the condensed consolidated financial statements in the period in which they are recognized. Comprehensive loss is defined as the change in equity during a period from transactions and other events and circumstances from non-owner sources, including unrealized gains and losses on investments and foreign currency translation gains and losses. Other comprehensive income, net includes unrealized gains or losses on short-term investments as well as foreign currency translation gains or losses.
Cash and Cash Equivalents	Cash and Cash Equivalents Cash and cash equivalents include cash in readily available checking and savings accounts, and money market funds. The Company considers all highly liquid investments with an original maturity of three months or less from the date of purchase to be cash equivalents. At June 30, 2024 and December 31, 2023, the Company's cash and cash equivalents were primarily comprised of money market funds.
Short-Term Investments	Short-Term Investments Available-for-sale securities are carried at fair value, with the unrealized gains and losses reported in comprehensive loss. The amortized cost of available-for-sale debt securities is adjusted for amortization of premiums and accretion of discounts to maturity. Such amortization and accretion are included in interest income. Realized gains and losses and declines in value judged to be other-than-temporary, if any, on available-for-sale securities are included in other income or expense. The cost of securities sold is based on the specific identification method. Interest and dividends on securities classified as available-for-sale are included in interest income.
Accounts Receivable	Accounts Receivable Accounts receivable includes trade accounts receivables from the Ono Asset Purchase Agreement (see Note 8). Reimbursable costs that have not been invoiced as of the balance sheet date are recorded as unbilled accounts receivable. As of June 30, 2024 and December 31, 2023, the Company had unbilled accounts receivable totaling $ 5.9 million and $ 3.7 million, respectively, classified as accounts receivable on its condensed consolidated balance sheet. The Company makes judgments as to its ability to collect outstanding receivables and provide an allowance for receivables when collection becomes doubtful. Allowance for credit risk for accounts receivable is established based on various factors including credit profiles of the Company’s customers, historical payments and current economic trends. The Company reviews its allowance for accounts receivable by assessing individual accounts receivable over a specific aging and amount. The estimate of expected credit losses is based on information about past events, current economic conditions, and forecasts of future economic conditions that affect the collectability. Accounts receivable is written-off on a case by case basis, net of any amounts that may be collected. As of June 30, 2024 and December 31, 2023, no credit losses have been recorded by the Company.
Prepaid Expenses and Other Current Assets	Prepaid Expenses and Other Current Assets Prepaid expenses and other current assets consisted of the following (in thousands): June 30, December 31, 2024 2023 Australian research and development tax incentive $ 692 $ 2,054 Prepaid clinical development 556 1,008 Prepaid insurance 250 532 Other receivables 407 497 Prepaid other 473 422 Other current assets 317 235 Total prepaid expenses and other current assets $ 2,695 $ 4,748
Property and Equipment	Property and Equipment Property and equipment is stated at cost and depreciated using the straight-line method over the estimated useful lives of the assets (generally three to five years ).
Leases	Lea ses The Company determines if an arrangement is a lease at inception. Lease right-of-use assets represent the Company's right to use an underlying asset for the lease term and lease liabilities represent the Company's obligation to make lease payments arising from the lease. For opera ting leases with an initial term greater than 12 months, the Company recognizes operating lease right-of-use assets and operating lease liabilities based on the present value of lease payments over the lease term at the commencement date. Operating lease right-of-use assets are comprised of the lease liability plus any lease payments made and excludes lease incentives. Lease terms include options to renew or terminate the lease when the Company is reasonably certain that the renewal option will be exercised or when it is reasonably certain that the termination option will not be exercised. For the Company's operating leases, if the interest rate used to determine the present value of future lease payments is not readily determinable, the Company estimates its incremental borrowing rate as the discount rate for the lease. The Company's incremental borrowing rate is estimated to approximate the interest rate on a collateralized basis with similar terms and payments, and in similar economic environments. Lease expense for lease payments is recognized on a straight-line basis over the lease term. The Company has elected the practical expedient to not separate lease and non-lease components.
Impairment of Long-Lived Assets	Impairment of Long-Lived Assets Long-lived assets consist primarily of property and equipment. An impairment loss is recorded if and when events and circumstances indicate that assets might be impaired and the undiscounted cash flows estimated to be generated by those assets are less than the carrying amount of those assets. While the Company’s current and historical operating losses and negative cash flows are indicators of impairment, management believes that future cash flows to be received support the carrying value of its long-lived assets and, accordingly, has not recognized any impairment losses since inception.
Accrued Research and Development Expense	Accrued Research and Development Expense The Company is required to estimate its expenses resulting from its obligations under contracts with vendors, consultants and contract research organizations, in connection with conducting research and development activities. The financial terms of these contracts are subject to negotiations, which vary from contract to contract and may result in payment flows that do not match the periods over which materials or services are provided under such contracts. The Company reflects research and development expenses in its condensed consolidated financial statements by matching those expenses with the period in which services and efforts are expended. The Company accounts for these expenses according to the progress of the preclinical or clinical study as measured by the timing of various aspects of the study or related activities. The Company determines accrual estimates through review of the underlying contracts along with preparation of financial models taking into account discussions with research and other key personnel as to the progress of studies, or other services being conducted. During the course of a study, the Company adjusts its rate of expense recognition if actual results differ from its estimates. The Company classifies its estimates for accrued research and development expenses as accrued expenses on the accompanying condensed consolidated balance sheet.
Australian Research and Development Tax Incentive	Australian Research and Develop ment Tax Incentive Equillium Australia Pty Ltd (Equillium Australia), a wholly-owned subsidiary of Equillium, Inc., is eligible under the Australian Research and Development Tax Incentive Program (the Tax Incentive) to obtain a cash refund from the Australian Taxation Office (ATO) for eligible research and development expenditures. The cash refund is received by Equillium Australia upon filing of a Tax Incentive claim in connection with Equillium Australia’s annual income tax return. The Tax Incentive is a self-assess program whereby Equillium Australia must assess each year (i) if the entity is eligible, (ii) if the specific research and development activities are eligible and (iii) if the individual research and development expenditures have nexus to such research and development activities. Equillium Australia evaluates its eligibility under the Tax Incentive as of each balance sheet date based on the most current and relevant data available. Equillium Australia is able to continue to claim refunds under the Tax Incentive for as long as it remains eligible and continues to incur eligible research and development expenditures. Although Equillium Australia believes that it has complied with all relevant conditions of eligibility under the program for all periods claimed, the ATO has the right to review Equillium Australia’s qualifying programs and related expenditures for a period of up to four years. Additionally, the period open for review is indefinite if the ATO suspects fraud. If such a review were to occur, the ATO may have different interpretations of certain eligibility requirements. If the ATO disagreed with Equillium Australia’s assessments and any related subsequent appeals, it could require adjustment to and potential repayment of current or previous years’ claims already received. If Equillium Australia was unable to demonstrate a reasonably arguable position taken on such claims, the ATO could also assess penalties and interest on potential adjustment amounts. The Company has not provided any allowance for any such potential adjustments, should they occur in the future. The estimated Tax Incentive refund amounts are recognized as a reduction to research and development expense when there is reasonable assurance that the Tax Incentive refund amounts will be received, the relevant expenditure has been incurred, and the amount can be reliably measured. During the three months ended June 30, 2024 and 2023, the Company recorded $ 0.4 million and $ 0.5 million, respectively, as a reduction to research and development expenses related to the Tax Incentive. During the six months ended June 30, 2024 and 2023, the Company recorded $ 1.4 million and $ 1.2 million, respectively, as a reduction to research and development expenses related to the Tax Incentive. The Company classifies its estimate for the Tax Incentive as prepaid expenses and other current assets on the accompanying condensed consolidated balance sheet. As of June 30, 2024 and December 31, 2023, the Company recorded $ 0.7 million and $ 2.1 million within prepaid and other current assets attributed to the Tax Incentive, respectively.
Revenue Recognition	Revenue Recognition The Company recognizes revenue in a manner that depicts the transfer of control of a product or a service to a customer and reflects the amount of the consideration the Company is entitled to receive in exchange for such product or service. In doing so, the Company follows a five-step approach: (i) identify the contract with a customer, (ii) identify the performance obligations in the contract, (iii) determine the transaction price, (iv) allocate the transaction price to the performance obligations, and (v) recognize revenue when (or as) the customer obtains control of the product or service. The Company considers the terms of a contract and all relevant facts and circumstances when applying the revenue recognition standard. The Company applies the revenue recognition standard, including the use of any practical expedients, consistently to contracts with similar characteristics and in similar circumstances. A customer is a party that has entered into a contract with the Company, where the purpose of the contract is to obtain a product or a service that is an output of the Company’s ordinary activities in exchange for consideration. To be considered a contract, (i) the contract must be approved (in writing, orally, or in accordance with other customary business practices), (ii) each party’s rights regarding the product or the service to be transferred can be identified, (iii) the payment terms for the product or the service to be transferred can be identified, (iv) the contract must have commercial substance (that is, the risk, timing or amount of future cash flows is expected to change as a result of the contract), and (v) it is probable that the Company will collect substantially all of the consideration to which it is entitled to receive in exchange for the transfer of the product or the service. A performance obligation is defined as a promise to transfer a product or a service to a customer. The Company identifies each promise to transfer a product or a service (or a bundle of products or services, or a series of products and services that are substantially the same and have the same pattern of transfer) that is distinct. A product or a service is distinct if both (i) the customer can benefit from the product or the service either on its own or together with other resources that are readily available to the customer and (ii) the Company’s promise to transfer the product or the service to the customer is separately identifiable from other promises in the contract. Each distinct promise to transfer a product or a service is a unit of accounting for revenue recognition. If a promise to transfer a product or a service is not separately identifiable from other promises in the contract, such promises should be combined into a single performance obligation. The transaction price is the amount of consideration the Company is entitled to receive in exchange for the transfer of control of a product or a service to a customer. To determine the transaction price, the Company considers the existence of any significant financing component, the effects of any variable elements, noncash considerations and consideration payable to the customer. If a significant financing component exists, the transaction price is adjusted for the time value of money. If an element of variability exists, the Company must estimate the consideration it expects to receive and uses that amount as the basis for recognizing revenue as the product or the service is transferred to the customer. There are two methods for determining the amount of variable consideration: (i) the expected value method, which is the sum of probability-weighted amounts in a range of possible consideration amounts, and (ii) the mostly likely amount method, which identifies the single most likely amount in a range of possible consideration amounts. If a contract has multiple performance obligations, the Company allocates the transaction price to each distinct performance obligation in an amount that reflects the consideration the Company is entitled to receive in exchange for satisfying each distinct performance obligation. For each distinct performance obligation, revenue is recognized when (or as) the Company transfers control of the product or the service applicable to such performance obligation. In those instances where the Company first receives consideration in advance of satisfying its performance obligation, the Company classifies such consideration as deferred revenue until (or as) the Company satisfies such performance obligation. In those instances where the Company first satisfies its performance obligation prior to its receipt of consideration, the consideration is recorded as accounts receivable. The Company expenses incremental costs of obtaining and fulfilling a contract as and when incurred if the expected amortization period of the asset that would be recognized is one year or less, or if the amount of the asset is immaterial. Otherwise, such costs are capitalized as co ntract assets if they are incremental to the contract and amortized to expense proportionate to revenue recognition of the underlying contract.
Contract Assets	Contract Assets The Company does not have material amounts of contract assets since revenue is recognized as control of goods is transferred or as services are performed. There are a small number of research and development services that may occur over a period of time, but that period of time is generally very short in duration. Any contract assets that may arise are recorded in accounts receivable in the Company’s condensed consolidated balance sheet net of an allowance for credit losses. The Company's contract assets include trade accounts receivables from the Ono Asset Purchase Agreement (see Note 8). Reimbursable costs that have not been invoiced as of the balance sheet date are recorded as unbilled accounts receivable. As of June 30, 2024 and December 31, 2023, the Company had unbilled accounts receivable totaling $ 5.9 million and $ 3.7 million, respectively, classified as accounts receivable on its condensed consolidated balance sheets.
Contract Liabilities	Contract Liabilities The Company’s contract liabilities consist of advance payments and deferred revenue. The Company classifies advance payments and deferred revenue as current or noncurrent based on the timing of when it expects to recognize revenue. Generally, all contract liabilities are expected to be recognized within one year and are included in deferred revenue in the Company’s condensed consolidated balance sheet. The noncurrent portion of deferred revenue is included and separately disclosed in the Company’s condensed consolidated balance sheet.
Acquired In-Process Research and Development Expense	Acquired In-Process Research and Dev elopment Expense The Company has acquired, and may continue to acquire, the rights to develop new product candidates. Payments to acquire a new product candidate, as well as future milestone payments associated with asset acquisitions in which contingent payments are resolved are immediately expensed as acquired in-process research and development provided that the product candidate has not achieved regulatory approval for marketing and, absent obtaining such approval, has no alternative future use.
Research and Development	Research and Development Research and developm ent expenses include salaries and related overhead expenses, non-cash stock-based compensation expense, external research and development expenses incurred under arrangements with third parties, costs of services performed by consultants and contract research organizations, regulatory costs including those related to preparing and filing INDs with the FDA, pharmacovigilance costs related to drug safety monitoring and reporting, and external expenses related to CMC, formulation and device development, and supply of drug product. Research and development costs are expensed as incurred.
Patent Costs	Patent C osts The Company expenses all costs as incurred in connection with patent applications (including direct application fees, and the legal and consulting expenses rela ted to making such applications) and such costs are included in general and administrative expenses in the condensed consolidated statement of operations.
Stock-Based Compensation	Stock-Based Compensation The Company measures employee and non-employee stock-based awards, including stock options and stock purchase rights, at grant-date fair value and records compensation expense on a straight-line basis over the vesting period of the award. The Company uses the Black-Scholes option pricing model to value its stock option awards. Estimating the fair value of stock option awards requires management to apply judgment and make estimates of certain assumptions, including the volatility of the Company’s common stock, the expected term of the Company’s stock options, the expected dividend yield and the fair value of the Company’s common stock on the measurement date. As a result, if factors change and management uses different assumptions, stock-based compensation expense could be materially different for future awards.
Income Taxes	Incom e Taxes The Company accounts for income taxes under the asset and liability method, which requires the recognition of deferred tax assets and liabilities for the expected future tax consequences of events that have been included in the condensed consolidated financial statements. Under this method, deferred tax assets and liabilities are determined on the basis of the differences between the condensed consolidated financial statements and tax basis of assets and liabilities using enacted tax rates in effect for the year in which the differences are expected to reverse. The effect of a change in tax rates on deferred tax assets and liabilities is recognized in income in the period that includes the enactment date. The Company recognizes deferred tax assets to the extent that the Company believes these assets are more likely than not to be realized. In making such a determination, management considers all available positive and negative evidence, including future reversals of existing taxable temporary differences, projected future taxable income, tax-planning strategies, and results of recent operations. If management determines that the Company would be able to realize its deferred tax assets in the future in excess of their net recorded amount, management would make an adjustment to the deferred tax asset valuation allowance, which would reduce the provision for income taxes. Pursuant to the Internal Revenue Code of 1986, as amended (IRC), specifically Sections 382 and 383, the Company’s ability to use tax attribute carryforwards to offset future taxable income is limited if the Company experiences a cumulative change in ownership of more than 50% within a three-year testing period. The Company has not completed an ownership change analysis pursuant to IRC Section 382 subsequent to June 30, 2023 and may also experience ownership changes in the future as a result of subsequent shifts in stock ownership. If ownership changes within the meaning of IRC Section 382 are identified as having occurred, the amount of remaining tax attribute carryforwards available to offset future taxable income and income tax expense in future years may be significantly restricted or eliminated, including those acquired through Bioniz. Further, the Company’s deferred tax assets associated with such tax attributes could be significantly reduced or eliminated upon realization of an ownership change within the meaning of IRC Section 382. If eliminated, the related asset would be removed from the deferred tax asset schedule, with a corresponding reduction in the valuation allowance. Additionally, limitations on the utilization of the Company’s tax attribute carryforwards can increase the amount of taxable income and current income tax expense recognized. Due to the existence of the valuation allowance, ownership change limitations that are not significant may not impact the Company's effective tax rate. The Tax Cuts and Jobs Act of 2017 amended IRC Section 174 to eliminate the immediate expensing of research and experimental (R&E) expenditures for amounts paid or incurred in tax years beginning after December 31, 2021. The rules of IRC Section 174, as amended, require taxpayers to charge their R&E expenditures and software development costs (collectively, R&E expenditures) to a capital account. Capitalized costs are required to be amortized over five or fifteen years for research performed within the United States or foreign jurisdictions, respectively. The Company records uncertain tax positions on the basis of a two-step process whereby (1) management determines whether it is more likely than not that the tax positions will be sustained on the basis of the technical merits of the position and (2) for those tax positions that meet the more- likely-than-not recognition threshold, management recognizes the largest amount of tax benefit that is more than 50 percent likely to be realized upon ultimate settlement with the related tax authority. The Company recognizes interest and penalties related to unrecognized tax benefits within income tax expense. Any accrued interest and penalties are included within the related tax liability.
Net Income (Loss) per Share	Net Income (Loss) per Share Basic net income (loss) per share is calculated by dividing the net income (loss) by the weighted-average number of common shares outstanding for the period. Diluted net income (loss) per share is calculated by dividing the net income (loss) by the sum of the weighted average number of common shares outstanding and potentially dilutive common shares outstanding for the period. The Company’s potentially dilutive securities include outstanding options under the Company’s 2018 Equity Incentive Plan, 2024 Inducement Plan and outstanding warrants to purchase common stock. Potentially dilutive common shares are only included when their effect is dilutive. In loss periods, basic and diluted loss per share are identical since the effect of potentially dilutive securities is anti-dilutive and therefore excluded. Potentially dilutive common shares from options and warrants are determined using the average share price for each period under the treasury stock method. In addition, proceeds from exercises of options and warrants and the average amount of unrecognized compensation expenses are assumed to be used to repurchase shares. The following table presents the weighted-average number of common shares used to calculate basic and diluted net income (loss) per share: Three Months Ended Six Months Ended 2024 2023 2024 2023 Weighted-average number of common shares used in calculating basic net income (loss) per share 35,292,035 34,449,769 35,273,394 34,432,057 Weighted average number of common shares used in calculating diluted net income (loss) per share 36,589,774 34,449,769 35,273,394 34,432,057 Anti-dilutive shares: Common stock options 7,886,188 7,317,199 9,183,927 7,317,199 Common stock warrants 1,366,141 1,366,141 1,366,141 1,366,141 Potentially dilutive shares excluded from calculation due to antidilutive effect 9,252,329 8,683,340 10,550,068 8,683,340

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	6 Months Ended
	Jun. 30, 2024
Accounting Policies [Abstract]
Summary of Weighted-Average Number of Common Shares Used to Calculate Basic and Diluted Net Income Loss Per Share	The following table presents the weighted-average number of common shares used to calculate basic and diluted net income (loss) per share: Three Months Ended Six Months Ended 2024 2023 2024 2023 Weighted-average number of common shares used in calculating basic net income (loss) per share 35,292,035 34,449,769 35,273,394 34,432,057 Weighted average number of common shares used in calculating diluted net income (loss) per share 36,589,774 34,449,769 35,273,394 34,432,057 Anti-dilutive shares: Common stock options 7,886,188 7,317,199 9,183,927 7,317,199 Common stock warrants 1,366,141 1,366,141 1,366,141 1,366,141 Potentially dilutive shares excluded from calculation due to antidilutive effect 9,252,329 8,683,340 10,550,068 8,683,340
Schedule of Prepaid Expenses and Other Current Assets	Prepaid expenses and other current assets consisted of the following (in thousands): June 30, December 31, 2024 2023 Australian research and development tax incentive $ 692 $ 2,054 Prepaid clinical development 556 1,008 Prepaid insurance 250 532 Other receivables 407 497 Prepaid other 473 422 Other current assets 317 235 Total prepaid expenses and other current assets $ 2,695 $ 4,748

Fair Value of Financial Instr_2

Fair Value of Financial Instruments (Tables)	6 Months Ended
	Jun. 30, 2024
Fair Value Disclosures [Abstract]
Summary of Assets that Require Fair Value Measurements on Recurring Basis and Their Respective Input Levels Based on Fair Value Hierarchy	The following tables summarize the Company’s assets that require fair value measurements on a recurring basis and their respective input levels based on the fair value hierarchy (in thousands): Fair Value Measurements Using Quoted Prices in Significant Significant Active Markets Other Unobservable June 30, for Identical Observable Inputs 2024 Assets (Level 1) Inputs (Level 2) (Level 3) Short-term investments: U.S. treasury securities $ 22,242 $ 22,242 $ - $ - Total $ 22,242 $ 22,242 $ - $ - Fair Value Measurements Using Quoted Prices in Significant Significant Active Markets Other Unobservable December 31, for Identical Observable Inputs 2023 Assets (Level 1) Inputs (Level 2) (Level 3) Short-term investments: U.S. treasury securities $ 17,650 $ 17,650 $ - $ - Total $ 17,650 $ 17,650 $ - $ -

Certain Financial Statement C_2

Certain Financial Statement Caption Information (Tables)	6 Months Ended
	Jun. 30, 2024
Certain Financial Statement Caption Information [Abstract]
Schedule of Company's Short-Term Investments	The following table summarizes the Company’s short-term investments (in thousands): Maturity Amortized Unrealized Unrealized Estimated (in years) Cost Gains Losses Fair Value June 30, 2024 U.S. treasury securities 1 or less $ 22,252 - $ ( 10 ) $ 22,242 Total $ 22,252 $ - $ ( 10 ) $ 22,242 December 31, 2023 U.S. treasury securities 1 or less $ 17,632 18 - $ 17,650 Total $ 17,632 $ 18 $ - $ 17,650
Schedule of Accrued Expenses	Accrued expenses consisted of the following (in thousands): June 30, December 31, 2024 2023 Accrued payroll and other employee benefits $ 1,991 $ 3,054 Clinical development 3,436 1,850 Biocon and its subsidiaries chemistry, manufacturing and controls services - related party 363 719 Biocon clinical development related to ulcerative colitis study - related party 272 415 Non-clinical research 441 228 Other accruals 400 431 Total accrued expenses $ 6,903 $ 6,697

Leases (Tables)

Leases (Tables)	6 Months Ended
	Jun. 30, 2024
Leases [Abstract]
Summary of Additional Information Related to Leases	Additional information related to the Company’s leases as of and for the six months ended June 30, 2024, is as follows (in thousands, except lease term and discount rate): June 30, 2024 Balance sheet information Right-of-use assets $ 592 Lease liabilities, current $ 350 Lease liabilities, non-current 259 Total lease liabilities $ 609 Other information Weighted average remaining lease term 1.96 Weighted average discount rate 8.25 % Supplemental cash flow information Operating cash flows from operating leases $ 245 Right-of-use assets obtained in exchange for lease obligations $ —
Schedule of Maturities of Lease Liabilities	Maturities of lease liabilities as of June 30, 2024 were as follows (in thousands): Year ending December 31, 2024 (remaining six months) $ 247 2025 219 2026 169 2027 28 Total undiscounted lease payments 663 Less: imputed interest ( 54 ) Total lease liabilities $ 609

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	6 Months Ended
	Jun. 30, 2024
Equity [Abstract]
Summary of Stock Option Activity	The following table summarizes stock option activity during the six months ended June 30, 2024: Outstanding Options Weighted- Weighted Aggregate (a) Balances as of December 31, 2023 7,031,075 $ 0.90 Granted 2,210,700 $ 0.79 Exercised - $ - Forfeitures and cancellations ( 57,848 ) $ 0.76 Balances as of June 30, 2024 9,183,927 $ 0.87 7.61 $ 19 Options exercisable as of June 30, 2024 4,813,600 $ 0.96 6.51 $ 8 (a) Aggregate intrinsic value in this table was calculated as the positive difference, if any, between the closing price per share of the Company’s common stock on June 28, 2024 of $ 0.69 and the price of the underlying options.
Summary of Non-cash Stock-based Compensation Expense	The non-cash stock-based compensation expense for all stock awards, net of forfeitures recognized as they occur, that was recognized in the condensed consolidated statements of operations is as follows (in thousands): Three Months Ended Six Months Ended 2024 2023 2024 2023 Research and development $ 368 $ 377 $ 738 $ 787 General and administrative 584 557 1,186 1,185 Total $ 952 $ 934 $ 1,924 $ 1,972
Summary of Reserved Shares of Common Stock for Future Issuance	Common stock reserved for future issuance is as follows: June 30, December 31, 2024 2023 Stock options issued and outstanding 9,183,927 7,031,075 Warrants for common stock 1,366,141 1,366,141 Awards available under the 2018 Equity Incentive Plan 203,549 576,464 Awards available under the 2024 Inducement Plan 1,482,800 - Employee stock purchase plan 1,153,022 979,383 Total 13,389,439 9,953,063

Organization and Accounting P_2

Organization and Accounting Pronouncements - Additional Information (Details) $ in Millions	6 Months Ended
	Jun. 30, 2024 USD ($)
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
State of incorporation	DE
Cash, Cash equivalents and short-term investments	$ 33.3
Date of incorporation	Mar. 16, 2017
Accounting Standards Update 2021-08 [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Change in accounting principle, accounting standards update, adopted [true false]	true
Change in accounting principle, accounting standards update, adoption date	Jan. 01, 2024
Change in accounting principle, accounting standards update, immaterial effect [true false]	true
Accounting Standards Update [Extensible Enumeration]	Accounting Standards Update 2021-08 [Member]
Accounting Standards Update 2023-07 [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Accounting Standards Update [Extensible Enumeration]	Accounting Standards Update 2023-07 [Member]

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023	Dec. 31, 2023
Summary Of Significant Accounting Policies [Line Items]
Allowance for credit losses	$ 0		$ 0		$ 0
Accounts receivable	5,893		$ 5,893		3,735
Research and experimental expenditures capitalized cost amortization period			5 years
Prepaid expenses and other current assets tax incentive			$ 700		$ 2,100
Australian Taxation Office | Australian Research and Development Tax Incentive Program
Summary Of Significant Accounting Policies [Line Items]
Research and development tax incentive	$ 400	$ 500	$ 1,400	$ 1,200
Foreign
Summary Of Significant Accounting Policies [Line Items]
Research and experimental expenditures capitalized cost amortization period			15 years
Minimum
Summary Of Significant Accounting Policies [Line Items]
Property and equipment, useful lives	3 years		3 years
Percentage of tax benefit to be realized upon ultimate settlement with tax authority			50%
Maximum
Summary Of Significant Accounting Policies [Line Items]
Property and equipment, useful lives	5 years		5 years

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Schedule of Prepaid Expenses and Other Current Assets (Details) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Summary Of Significant Accounting Policies [Abstract]
Australian research and development tax incentive	$ 692	$ 2,054
Prepaid clinical development	556	1,008
Prepaid insurance	250	532
Other receivables	407	497
Prepaid other	473	422
Other current assets	317	235
Total prepaid expenses and other current assets	$ 2,695	$ 4,748

Summary of Significant Accoun_6

Summary of Significant Accounting Policies - Summary of Weighted-Average Number of Common Shares Used to Calculate Basic and Diluted Net Income Loss Per Share (Details) - shares	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Weighted-average number of common shares used in calculating basic net income (loss) per share	35,292,035	34,449,769	35,273,394	34,432,057
Weighted average number of common shares used in calculating diluted net income (loss) per share	36,589,774	34,449,769	35,273,394	34,432,057
Antidilutive securities not included in calculation of diluted net loss per share	9,252,329	8,683,340	10,550,068	8,683,340
Employee Stock Option [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities not included in calculation of diluted net loss per share	7,886,188	7,317,199	9,183,927	7,317,199
Common Stock Warrants
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities not included in calculation of diluted net loss per share	1,366,141	1,366,141	1,366,141	1,366,141

Fair Value of Financial Instr_3

Fair Value of Financial Instruments - Summary of Assets that Require Fair Value Measurements on Recurring Basis and Their Respective Input Levels Based on Fair Value Hierarchy (Details) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total short-term investments	$ 22,242	$ 17,650
U.S. Treasury Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total short-term investments	22,242	17,650
Level 1
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total short-term investments	22,242	17,650
Level 1 | U.S. Treasury Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total short-term investments	$ 22,242	$ 17,650

Fair Value of Financial Instr_4

Fair Value of Financial Instruments - Additional Information (Details) - USD ($)	Jun. 30, 2024	Dec. 31, 2023
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Financial liabilities	$ 0	$ 0

Certain Financial Statement C_3

Certain Financial Statement Caption Information - Schedule of Company's Short-Term Investments (Details) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	$ 22,252	$ 17,632
Unrealized Gains		18
Unrealized losses	(10)	0
Estimated Fair Value	22,242	17,650
U.S. Treasury Securities Maturing in One Year or Less
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	22,252	17,632
Unrealized Gains		18
Unrealized losses	(10)	0
Estimated Fair Value	$ 22,242	$ 17,650
U.S. Treasury Securities Maturing in One Year or Less | Maximum
Schedule Of Available For Sale Securities [Line Items]
Maturity (in years)	1 year	1 year

Certain Financial Statement C_4

Certain Financial Statement Caption Information - Additional Information (Details)	6 Months Ended
	Jun. 30, 2024 USD ($)
Schedule Of Available For Sale Securities [Line Items]
Other than temporary impairment loss investments available for sale securities	$ 0
Minimum
Schedule Of Available For Sale Securities [Line Items]
Available for sale Securities debt maturities period	1 year
Maximum
Schedule Of Available For Sale Securities [Line Items]
Available for sale Securities debt maturities period	2 years

Certain Financial Statement C_5

Certain Financial Statement Caption Information - Schedule of Accrued Expenses (Details) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Accrued Liabilities, Current [Abstract]
Accrued payroll and other employee benefits	$ 1,991	$ 3,054
Clinical development	3,436	1,850
Biocon chemistry, manufacturing and controls services	363	719
Biocon clinical development related to ulcerative colitis study	272	415
Non-clinical research	441	228
Other accruals	400	431
Total accrued expenses	$ 6,903	$ 6,697

Acquisition - Additional Inform

Acquisition - Additional Information (Details) - Bioniz - USD ($) $ in Thousands	Aug. 14, 2023	Feb. 14, 2022	Dec. 31, 2023
Business Acquisition [Line Items]
Business acquisition, common stock shares issued		4,820,230
Business acquisition, term for finalization after the closing		18 months
Shares of common stock issued	849,133
Adjustment to additional paid-in capital			$ 0
18 Months after Closing
Business Acquisition [Line Items]
Business acquisition, common stock shares issued		879,252
Achievement of Regulatory Events
Business Acquisition [Line Items]
Contingent payments		$ 57,500
Achievement of Commercialization Events
Business Acquisition [Line Items]
Contingent payments		$ 250,000
Maximum
Business Acquisition [Line Items]
Business acquisition, common stock shares issued		5,699,492

Notes Payable - Additional Info

Notes Payable - Additional Information (Details)		1 Months Ended		6 Months Ended
	May 25, 2023 USD ($)	May 31, 2021 Installment	Sep. 30, 2019 USD ($) Installment $ / shares shares	Jun. 30, 2024	Dec. 31, 2023 USD ($)	Apr. 23, 2021
Short Term Debt [Line Items]
Term Loan maturity date			Jun. 01, 2024
Line of Credit
Short Term Debt [Line Items]
Debt instrument, frequency of periodic payment			monthly
Debt instrument, interest rate, basis for effective rate			prime rate
Percentage of final principal payment			5%
Required notice period for debt prepayment			30 days
Debt prepayment fee as percent on year one			3%
Debt prepayment fee as percent on year two			2%
Debt prepayment fee as percent from year three			1%
Line of Credit | Prime Rate
Short Term Debt [Line Items]
Debt instrument, basis spread on variable rate			3%
Line of Credit | Minimum
Short Term Debt [Line Items]
Debt instrument, interest rate, stated percentage			8.25%
Loan Agreement
Short Term Debt [Line Items]
Line of credit facility frequency of payments principal and interest | Installment		24
Debt instrument, frequency of periodic payment				monthly
Debt instrument, prepayment and termination amount	$ 6,800,000
Repayment of remaining principal amount and interest outstanding	6,200,000
Debt instrument, prepayment fee	62,000
Debt instrument, final payment fee	$ 500,000
Long term loan obligation					$ 0
Loan Agreement | Minimum
Short Term Debt [Line Items]
Debt instrument, interest rate, effective percentage						4.50%
Loan Agreement | Maximum
Short Term Debt [Line Items]
Debt instrument, interest rate, effective percentage						5%
Term Loan
Short Term Debt [Line Items]
Borrowings under loan agreement			$ 10,000,000
Line of credit facility frequency of payments principal and interest | Installment			36
Lenders warrants exercisable for shares | shares			80,428
Warrants exercisable, per share exercise price | $ / shares			$ 3.73

Leases - Additional Information

Leases - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Lessee, Lease, Description [Line Items]
Operating lease expense	$ 0.1	$ 0.1	$ 0.3	$ 0.3
Office Space
Lessee, Lease, Description [Line Items]
Lease expiration year			2027
Lease expired date			2023-02
Laboratory Space
Lessee, Lease, Description [Line Items]
Lease expired date			2025-02

Leases - Summary of Additional

Leases - Summary of Additional Information Related to Leases (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2024	Dec. 31, 2023	Jun. 30, 2023
Assets and Liabilities, Lessee [Abstract]
Right-of-use assets	$ 592	$ 796
Lease liabilities, current	350	440
Lease liabilities, non-current	259	$ 384
Total lease liabilities	$ 609		$ 609
Other information
Weighted average remaining lease term	1 year 11 months 15 days
Weighted average discount rate	8.25%
Supplemental cash flow information
Operating cash flows from operating leases	$ 245
Right-of-use assets obtained in exchange for lease obligations	$ 0

Leases - Schedule of Maturities

Leases - Schedule of Maturities of Lease Liabilities (Details) - USD ($) $ in Thousands	Jun. 30, 2024	Jun. 30, 2023
Lessee, Operating Lease, Liability, to be Paid, Fiscal Year Maturity [Abstract]
2024 (remaining six months)	$ 247
2025	219
2026	169
2027	28
Total undiscounted lease payments	663
Less: imputed interest	(54)
Total lease liabilities	$ 609	$ 609

Partnerships - Additional Infor

Partnerships - Additional Information (Details) $ in Thousands, ¥ in Billions	1 Months Ended		3 Months Ended		6 Months Ended		31 Months Ended
	Dec. 31, 2022 USD ($)	May 31, 2017 USD ($)	Jun. 30, 2024 USD ($)	Jun. 30, 2023 USD ($)	Jun. 30, 2024 USD ($)	Jun. 30, 2023 USD ($)	Nov. 30, 2019 shares	Dec. 31, 2023 USD ($)	Aug. 03, 2023 USD ($)	Mar. 16, 2023 USD ($)	Mar. 16, 2023 JPY (¥)	Dec. 05, 2022 USD ($)	Dec. 05, 2022 JPY (¥)
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Recognized revenue			$ 13,853	$ 9,124	$ 24,542	$ 18,003
Deferred revenue current			8,430		8,430			$ 15,729
Ono | Upfront Payment Amortization
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Recognized revenue			1,300		1,300
Ono | Maximum
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Estimated research and development funding			76,800		76,800
Updation of estimated research and development funding			102,600		102,600
Ono | Minimum
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Estimated research and development funding			70,800		70,800
Updation of estimated research and development funding			96,600		$ 96,600
Ono | Asset Purchase Agreement
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Upfront non-refundable and non-creditable payment receivable, upon exchange of option												$ 26,400	¥ 3.5
One-time payment receivable, upon exercises the option										$ 35,000	¥ 5
Option period expiry condition					the option period will expire 90 days following the delivery of topline data from the EQUALISE clinical study in lupus nephritis (LN) and the results of the interim analysis from the Phase 3 EQUATOR clinical study in aGVHD. In April 2024, the Company delivered topline data from the EQUALISE clinical study in LN to Ono, and on August 1, 2024 we delivered the results of the interim analysis from the Phase 3 EQUATOR clinical study in aGVHD to Ono, which results in the expiration of Ono's option period on October 30, 2024.
Upfront non-refundable and non-creditable payment invoiced												25,800	¥ 3.5
Upfront payment received	$ 26,400
Foreign curreny realized gain	$ 600
Initial transaction price												102,600
Upfront and non-creditable payment invoiced												25,800
Estimated research and development funding												76,800
Deferred revenue												$ 25,800
Recognized revenue			13,900	$ 9,100	$ 24,500	$ 18,000
Deferred revenue current			8,400		8,400
Proceeds from research and development fees					53,100
Ono | Asset Purchase Agreement | Research and Development Services
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Recognized revenue			9,200		17,200
Ono | Asset Purchase Agreement | Upfront Payment Amortization
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Recognized revenue			$ 4,700		$ 7,300
Ono | Asset Purchase Agreement | Maximum
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Eligible to receive payment on achievement of certain development milestones									$ 101,400
Biocon
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Common stock shares issued | shares							2,316,134
Biocon | Collaboration and License Agreement
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Regulatory milestone payments		$ 30,000
Sales milestone payments		$ 565,000

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands		1 Months Ended		3 Months Ended		6 Months Ended
	Aug. 07, 2023	Oct. 31, 2023	Jul. 31, 2023	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023	Mar. 06, 2024	Dec. 31, 2023
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock, shares authorized				200,000,000		200,000,000			200,000,000
Common stock, par value				$ 0.0001		$ 0.0001			$ 0.0001
Preferred stock, shares authorized				10,000,000		10,000,000
Preferred stock, par value				$ 0.0001		$ 0.0001
Common stock, shares outstanding				35,424,388		35,424,388			35,254,752
Number of shares available for issuance				13,389,439		13,389,439			9,953,063
Total non-cash stock-based compensation expense				$ 952	$ 934	$ 1,924	$ 1,972
Unamortized stock compensation for stock options				4,700		$ 4,700
Weighted-average recognition period of stock option unamortized						2 years 8 months 15 days
Repriced Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Vested and Expected to Vest, Outstanding, Number	0
Total non-cash stock-based compensation expense	$ 1,300
Repriced Options | General and Administrative and Research and Development Expense
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total non-cash stock-based compensation expense				$ 200		$ 400
Vested Repricing Option
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total non-cash stock-based compensation expense	800
Unvested Repriced Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total non-cash stock-based compensation expense	$ 500
2018 Equity Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares available for issuance				17,200		17,200
2018 Equity Incentive Plan | Repriced Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Repricing of outstanding options	6,628,589
2024 Inducement Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares available for issuance								1,500,000
Stock Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Repricing of outstanding options				9,183,927		9,183,927			7,031,075
Common Stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock repurchased			$ 7,500			$ 300
Common stock repurchased, Shares						298,385
Common Stock | Two Thousand Twenty Three ATM Facility Member
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Issuance of common stock, Shares						0
Common stock shares maximum aggregate offering price		$ 21,950
Common Stock Warrants
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares available for issuance				1,366,141		1,366,141			1,366,141

Stockholders' Equity - Summary

Stockholders' Equity - Summary of Stock Option Activity (Details) - Stock Options $ / shares in Units, $ in Thousands	6 Months Ended
	Jun. 30, 2024 USD ($) $ / shares shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of Outstanding Options, Beginning Balance | shares	7,031,075
Number of Outstanding Options, Granted | shares	2,210,700
Number of Outstanding Options, Exercised | shares	0
Number of Outstanding Options, Forfeitures and Cancellations | shares	(57,848)
Number of Outstanding Options, Ending Balance | shares	9,183,927
Number of Outstanding Options, Exercisable | shares	4,813,600
Weighted- Average Exercise Price Per Share, Beginning Balance | $ / shares	$ 0.9
Weighted- Average Exercise Price Per Share, Granted | $ / shares	0.79
Weighted- Average Exercise Price Per Share, Exercised | $ / shares	0
Weighted- Average Exercise Price Per Share, Forfeitures and Cancellations | $ / shares	0.76
Weighted- Average Exercise Price Per Share, Ending Balance | $ / shares	0.87
Weighted- Average Exercise Price Per Share, Exercisable | $ / shares	$ 0.96
Weighted Average Remaining Contractual Term, Options Outstanding	7 years 7 months 9 days
Weighted Average Remaining Contractual Term, Options Exercisable	6 years 6 months 3 days
Aggregate Intrinsic Value, Options Outstanding | $	$ 19
Aggregate Intrinsic Value, Options Exercisable | $	$ 8

Stockholders' Equity - Summar_2

Stockholders' Equity - Summary of Stock Option Activity (Parenthetical) (Details)	Jun. 30, 2024 $ / shares
Stock Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Closing stock price per share	$ 0.69

Stockholders' Equity - Summar_3

Stockholders' Equity - Summary of Total Non-cash Stock-based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total non-cash stock-based compensation expense	$ 952	$ 934	$ 1,924	$ 1,972
Research and Development Expense
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total non-cash stock-based compensation expense	368	377	738	787
General and Administrative Expense
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total non-cash stock-based compensation expense	$ 584	$ 557	$ 1,186	$ 1,185

Stockholders' Equity - Summar_4

Stockholders' Equity - Summary of Common Stock Reserved for Future Issuance (Details) - shares	Jun. 30, 2024	Dec. 31, 2023
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total common stock reserved for future issuance	13,389,439	9,953,063
Stock Options Issued and Outstanding
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total common stock reserved for future issuance	9,183,927	7,031,075
Warrants for Common Stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total common stock reserved for future issuance	1,366,141	1,366,141
Awards Available Under 2018 Equity Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total common stock reserved for future issuance	203,549	576,464
Awards available under the 2024 Inducement Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total common stock reserved for future issuance	1,482,800	0
Employee Stock Purchase Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total common stock reserved for future issuance	1,153,022	979,383

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Income Tax Disclosure [Abstract]
Income tax expense	$ 0	$ 8,000	$ 0	$ 68,000

Related Party Transactions - Ad

Related Party Transactions - Additional Information (Details) - USD ($)	1 Months Ended	3 Months Ended		6 Months Ended
	Jul. 31, 2023	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023	Dec. 31, 2023
Related Party Transaction [Line Items]
Accrued expenses		$ 6,903,000		$ 6,903,000		$ 6,697,000
Accounts payable		4,486,000		4,486,000		4,707,000
Pre-BLA CMC Projects
Related Party Transaction [Line Items]
Several purchase orders				6,100,000
Research and development expense		1,100,000	$ 0	2,100,000	$ 0
Biocon
Related Party Transaction [Line Items]
Expected clinical study costs				1,500,000
Research and development expense related to clinical study costs		200,000	$ 100,000	400,000	$ 200,000
Accrued expenses related to clinical study costs		300,000		300,000		400,000
Accounts payable		300,000		300,000		0
Syngene International Limited | Master Services Agreement
Related Party Transaction [Line Items]
Related party transaction, amount for CMC activities and projects	$ 5,400,000
Firm commitment amount				700,000
Biocon and Syngene
Related Party Transaction [Line Items]
Accrued expenses		400,000		400,000		$ 700,000
Accounts payable		$ 1,200,000		$ 1,200,000