Equillium (EQ) 10-K 25 Mar 24 2023 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Mar. 20, 2024	Jun. 30, 2023
Cover [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2023
Document Fiscal Year Focus	2023
Entity Current Reporting Status	Yes
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Document Fiscal Period Focus	FY
Trading Symbol	EQ
Entity Registrant Name	EQUILLIUM, INC.
Entity Central Index Key	0001746466
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	false
Document Financial Statement Error Correction	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		35,254,752
Entity Public Float			$ 16
Title of 12(b) Security	Common Stock, par value $0.0001 per share
Entity File Number	001-38692
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	82-1554746
Entity Interactive Data Current	Yes
Security Exchange Name	NASDAQ
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 Annual Report	true
Document Transition Report	false
Documents Incorporated by Reference	DOCUMENTS INCORPORATED BY REFERENCE Part III of this Annual Report on Form 10-K incorporates by reference certain information from the registrant’s definitive Proxy Statement for its 2024 annual meeting of stockholders, which the registrant intends to file pursuant to Regulation 14A with the Securities and Exchange Commission not later than 120 days after the registrant’s fiscal year end of December 31, 2023. Except with respect to information specifically incorporated by reference in this Form 10-K, the Proxy Statement is not deemed to be filed as part of this Form 10-K.
Auditor Name	KPMG LLP
Auditor Location	San Diego, California, United States
Auditor Firm ID	185

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Current assets:
Cash and cash equivalents	$ 23,216	$ 59,107
Short-term investments	17,650	11,916
Accounts receivable	3,735	2,838
Prepaid expenses and other current assets	4,748	2,874
Total current assets	49,349	76,735
Operating lease right-of-use assets	796	1,191
Property and equipment, net	315	391
Other assets	70	104
Total assets	50,530	78,421
Current liabilities:
Accounts payable	4,707	3,977
Accrued expenses	6,697	7,239
Current portion of deferred revenue	15,729	14,700
Current portion of notes payable		5,714
Current portion of operating lease liabilities	440	408
Total current liabilities	27,573	32,038
Long-term notes payable		3,239
Long-term deferred revenue		10,378
Long-term operating lease liabilities	384	824
Total liabilities	27,957	46,479
Commitments and contingencies
Stockholders' equity:
Common stock, $0.0001 par value; 200,000,000 shares authorized as of December 31, 2023 and 2022; 35,254,752 and 34,414,149 shares issued and outstanding as of December 31, 2023 and 2022, respectively	3	3
Additional paid-in capital	208,170	204,268
Accumulated other comprehensive income	140	76
Accumulated deficit	(185,740)	(172,405)
Total stockholders' equity	22,573	31,942
Total liabilities and stockholders' equity	$ 50,530	$ 78,421

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2023	Dec. 31, 2022
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	35,254,752	34,414,149
Common stock, shares outstanding	35,254,752	34,414,149

Consolidated Statements of Oper

Consolidated Statements of Operations and Comprehensive Loss - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Income Statement [Abstract]
Revenue	$ 36,084,000	$ 15,759,000
Operating expenses:
Research and development	37,039,000	37,547,000
Acquired in-process research and development	0	23,049,000
General and administrative	13,567,000	17,239,000
Total operating expenses	50,606,000	77,835,000
Loss from operations	(14,522,000)	(62,076,000)
Other income (expense), net:
Interest expense	(491,000)	(1,053,000)
Interest income	2,334,000	420,000
Other (expense) income, net	(76,000)	281,000
Total other income (expense), net	1,767,000	(352,000)
Net loss before income tax expense	(12,755,000)	(62,428,000)
Income tax expense	580,000	0
Net loss	(13,335,000)	(62,428,000)
Other comprehensive income, net:
Unrealized gain (loss) on available-for-sale securities, net	108,000	(38,000)
Foreign currency translation (loss) gain	(44,000)	252,000
Total other comprehensive income, net	64,000	214,000
Comprehensive loss	$ (13,271,000)	$ (62,214,000)
Net loss per share, basic	$ (0.38)	$ (1.85)
Net loss per share, diluted	$ (0.38)	$ (1.85)
Weighted-average number of common shares outstanding, basic	34,726,384	33,727,945
Weighted-average number of common shares outstanding, diluted	34,726,384	33,727,945

Consolidated Statements of Stoc

Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Bioniz	Common Stock	Common Stock Bioniz	Additional Paid-in Capital	Additional Paid-in Capital Bioniz	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit
Balance at Dec. 31, 2021	$ 66,505		$ 2		$ 176,618		$ (138)	$ (109,977)
Balance, Shares at Dec. 31, 2021			29,455,668
Issuance of common stock		$ 22,542		$ 1		$ 22,541
Issuance of common stock, Shares				4,820,230
Issuance of common stock under employee stock purchase plan	215				215
Issuance of common stock under employee stock purchase plan, Shares			138,251
Vesting of restricted stock liability	53				53
Stock-based compensation expense	4,841				4,841
Comprehensive income	214						214
Net loss	(62,428)							(62,428)
Balance at Dec. 31, 2022	31,942		$ 3		204,268		76	(172,405)
Balance, Share at Dec. 31, 2022			34,414,149
Issuance of common stock, Shares				849,133
Issuance of common stock under employee stock purchase plan	165				165
Issuance of common stock under employee stock purchase plan, Shares			289,855
Common stock repurchased	(260)		$ (300)		(260)
Common stock repurchased, Shares			(298,385)
Stock-based compensation expense	3,997				3,997
Comprehensive income	64						64
Net loss	(13,335)							(13,335)
Balance at Dec. 31, 2023	$ 22,573		$ 3		$ 208,170		$ 140	$ (185,740)
Balance, Share at Dec. 31, 2023			35,254,752

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Operating activities:
Net loss	$ (13,335,000)	$ (62,428,000)
Adjustments to reconcile net loss to cash used in operating activities:
Acquired in-process research and development	0	23,049,000
Depreciation	126,000	118,000
Stock-based compensation	3,997,000	4,841,000
Net unrealized loss on foreign currency transactions	58,000	260,000
Amortization of term loan discount and issuance costs	180,000	203,000
Amortization of premium and accretion of discounts on investments	(914,000)	127,000
Deferred revenue	(9,349,000)	25,078,000
Changes in operating assets and liabilities:
Accounts receivable	(897,000)	(2,838,000)
Prepaid expenses and other current assets	(1,805,000)	(158,000)
Accounts payable	723,000	2,508,000
Accrued expenses	(554,000)	432,000
Right-of-use assets and lease liabilities, net	(13,000)	75,000
Net cash used in operating activities	(21,783,000)	(8,733,000)
Investing activities:
Purchases of property and equipment	(50,000)	(279,000)
Purchases of short-term investments	(54,712,000)	(14,962,000)
Maturities of short-term investments	50,000,000	33,225,000
Net cash (used in) provided by investing activities	(4,762,000)	18,684,000
Financing activities:
Repayment of notes payable	(9,133,000)	(1,429,000)
Common stock repurchased	(260,000)
Net cash used in financing activities	(9,228,000)	(1,215,000)
Effect of exchange rate changes on cash and cash equivalents	(118,000)	5,000
Net (decrease) increase in cash and cash equivalents	(35,891,000)	8,741,000
Cash and cash equivalents at beginning of period	59,107,000	50,366,000
Cash and cash equivalents at end of period	23,216,000	59,107,000
Supplemental cash flow information:
Cash paid for interest	946,000	847,000
Cash paid for income taxes	580,000
Bioniz
Investing activities:
Cash acquired in Bioniz acquisition		700,000
Supplemental cash flow information:
Fair value of Bioniz assets acquired		23,049,000
Issuance of common stock for Bioniz acquisition		(22,542,000)
Bioniz net liabilities assumed		507,000
Follow-on Offering
Financing activities:
Proceeds from issuance of common stock under employee stock purchase plan	$ 165,000	$ 214,000

Pay vs Performance Disclosure

Pay vs Performance Disclosure - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Pay vs Performance Disclosure
Net Income (Loss)	$ (13,335)	$ (62,428)

Insider Trading Arrangements

Insider Trading Arrangements	3 Months Ended
	Dec. 31, 2023 shares
Trading Arrangements, by Individual
Material Terms of Trading Arrangement	Trading Arrangements During the three-months ended December 31, 2023, one of our executive officers adopted a trading plan for the orderly disposition 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 Christine Zedelmayer , Chief Operating Officer Adoption December 12, 2023 X 322,823 December 12, 2024 (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	Christine Zedelmayer
Title	Chief Operating Officer
Rule 10b5-1 Arrangement Adopted	true
Non-Rule 10b5-1 Arrangement Adopted	false
Adoption Date	December 12, 2023
Termination Date	December 12, 2023
Aggregate Available	322,823
Expiration Date	December 12, 2024

Organization and Accounting Pro

Organization and Accounting Pronouncements	12 Months Ended
	Dec. 31, 2023
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. 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 first in-class, selective, tri-specific synthetic peptide engineered to specifically inhibit 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 first-in-class monoclonal antibody that selectively targets the immune checkpoint receptor CD6, which plays a central role in the modulation of effector T cell (T eff cell) activity and trafficking that drives a number of immuno-inflammatory diseases across multiple therapeutic areas. 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 preclinical development of EQ302, a potential first-in-class, orally delivered, bi-specific inhibitor of IL-15 and IL-21. 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 December 31, 2023, 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, filing three Investigational New Drug applications (INDs), conducting clinical development of the Company’s 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 December 31, 2023, the Company had $ 40.9 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, manufacturing and 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. Management believes that the Company’s cash, cash equivalents and short-term investments as of December 31, 2023, will be sufficient to fund operations for at least the next 12 months from the date this Annual Report on Form 10-K is filed with the Securities and Exchange Commission (SEC). Basis of Presentation The accompanying consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles (GAAP) and the rules and regulations of the SEC. 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 reclassifications have been made to prior-year amounts to conform to the current period presentation. Principles of Consolidation The accompanying 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 year-to-date periods. Foreign currency translation adjustments for the reported periods are included in accumulated other comprehensive income in the Company’s consolidated statements of comprehensive loss, and the cumulative effect is included in the stockholders’ equity section of the Company’s consolidated balance sheets. Recently Issued and Recently 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 accounting standards update will be effective for the Company beginning in the first quarter of fiscal 2024. The Company does not expect this accounting standards update to have a material impact on its 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 consolidated financial statements. No other new accounting pronouncements or legislation issued or effective as of December 31, 2023 have had, or are expected to have, a material impact on our consolidated financial statements.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2023
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies Use of Estimates The preparation of the Company’s 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 consolidated financial statements and accompanying notes. Significant estimates in the Company’s consolidated financial statements relate to accrued research and development expense, 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 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 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 Income (Loss) The Company is required to report all components of comprehensive loss, including net loss, in the 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 December 31, 2023 and 2022, 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 9). Reimbursable costs that have not been invoiced as of the balance sheet date are recorded as unbilled accounts receivable. As of December 31, 2023, and 2022, the Company had unbilled accounts receivable totaling $ 3.7 million and $ 2.8 million, respectively, classified as accounts receivable on its 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 each of December 31, 2023, and 2022, 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): December 31, 2023 2022 Australian research and development tax incentive $ 2,054 $ 1,006 Prepaid clinical development 1,008 449 Prepaid insurance 532 709 Other receivables 497 269 Prepaid other 422 433 Other current assets 235 8 Total prepaid expenses and other current assets $ 4,748 $ 2,874 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 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 operating 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 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 development 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 consolidated balance sheet. Australian Research and Development Tax Incentive The Company is eligible under the Australian Research and Development Tax Incentive Program, or the Tax Incentive, to obtain a cash refund from the Australian Taxation Office for eligible research and development expenditures. To be eligible, the filing entity must have revenue of less than AUD $ 20.0 million during the reimbursable period and cannot be controlled by income tax exempt entities. The Tax Incentive is recognized as a reduction to research and development expense when there is reasonable assurance that the Tax Incentive will be received, the relevant expenditure has been incurred, and the amount can be reliably measured. The Company classifies its estimate for the Tax Incentive as prepaid expenses and other current assets on the accompanying consolidated balance sheet. As of December 31, 2023 and 2022, the Company recorded $ 2.1 million and $ 1.0 million within prepaid expenses 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 contract 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 consolidated balance sheet net of an allowance for credit losses. The Company's contract assets includes trade accounts receivables from the Ono Asset Purchase Agreement (see Note 9). Reimbursable costs that have not been invoiced as of the balance sheet date are recorded as unbilled accounts receivable. As of December 31, 2023 and 2022, the Company had unbilled accounts receivable totaling $ 3.7 million and $ 2.8 million, respectively, classified as accounts receivable on its consolidated balance sheet. 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 consolidated balance sheet. The noncurrent portion of deferred revenue is included and separately disclosed in the Company’s consolidated balance sheet. Acquired In-Process Research and Development 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 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, and regulatory costs including those related to preparing and filing INDs with the FDA. Research and development costs are expensed as incurred. Patent Costs The Company expenses all costs as incurred in connection with patent applications (including direct application fees, and the legal and consulting expenses related to making such applications) and such costs are included in general and administrative expenses in the consolidated statement of operations. Stock-based Compensation The Company measures employee and nonemployee stock-based awards, including stock options and 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 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 consolidated financial statements. Under this method, deferred tax assets and liabilities are determined on the basis of the differences between the 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 completed an ownership change analysis through June 30, 2023 pursuant to IRC Section 382 and determined that the Company’s ability to offset taxable income in 2023 is not expected to be impacted by ownership changes occurring prior to that date. If ownership changes within the meaning of IRC Section 382 occur in the future, 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 Loss per Share Basic net loss per share is calculated by dividing the net loss by the weighted-average number of common shares outstanding for the period. Diluted net loss per share is computed by dividing the net loss by the weighted average number of common shares and common share equivalents outstanding for the period. Common stock equivalents are only included when their effect is dilutive. The Company’s potentially dilutive securities include outstanding options under the Company’s equity incentive plan and outstanding warrants to purchase common stock, each of which have been excluded from the computation of diluted net loss per share as they would be anti-dilutive to the net loss per share. For all periods presented, there is no difference in the number of shares used to calculate basic and diluted shares outstanding due to the Company’s net loss position. Potentially dilutive securities not included in the calculation of diluted net loss per share attributable to common stockholders because to do so would be anti-dilutive are as follows (in common stock equivalent shares): Year Ended 2023 2022 Common stock options 7,031,075 5,102,501 Common stock warrants 1,366,141 1,366,141 Total 8,397,216 6,468,642

Fair Value of Financial Instrum

Fair Value of Financial Instruments	12 Months Ended
	Dec. 31, 2023
Fair Value Disclosures [Abstract]
Fair Value of Financial Instruments	3. Fair Value of Financial Instruments The accounting guidance defines fair value, establishes a consistent framework for measuring fair value and expands disclosure for each major asset and liability category measured at fair value on either a recurring or nonrecurring basis. Fair value is defined as an exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. As such, fair value is a market-based measurement that should be determined based on assumptions that market participants would use in pricing an asset or liability. As a basis for considering such assumptions, the accounting guidance establishes a three-tier fair value hierarchy, which prioritizes the inputs used in measuring fair value as follows: Level 1 —Unadjusted quoted prices in active markets that are accessible at the measurement date for identical, unrestricted assets or liabilities. Level 2 —Quoted prices for similar assets and liabilities in active markets, quoted prices in markets that are not active, or inputs which are observable, either directly or indirectly, for substantially the full term of the asset or liability. Level 3 —Prices or valuation techniques that require inputs that are both significant to the fair value measurement and unobservable (i.e., supported by little or no market activity). Financial assets measured at fair value on a recurring basis consist of the Company’s cash equivalents and short-term investments. Cash equivalents consisted of money market funds and short-term investments consisted of U.S. treasury securities and certificates of deposit. The Company obtains pricing information from its investment manager and generally determines the fair value of investment securities using standard observable inputs, including reported trades, broker/dealer quotes, and bid and/or offers. 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 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 $ - $ - Fair Value Measurements Using Quoted Prices in Significant Significant Active Markets Other Unobservable December 31, for Identical Observable Inputs 2022 Assets (Level 1) Inputs (Level 2) (Level 3) Short-term investments: U.S. treasury securities $ 11,916 $ 11,916 $ - $ - Total $ 11,916 $ 11,916 $ - $ - U.S. treasury securities and certificates of deposit 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 expenses and other current assets, accounts payable, and accrued liabilities, approximate their fair value due to their short maturities. At December 31, 2022, the carrying amount of the Company’s notes payable was $ 9.0 million, which approximated their fair value as the terms of the notes are consistent with the market terms of transactions with similar profiles (Level 2 inputs). The notes payable were paid off during 2023 and were no longer outstanding as of December 31, 2023. 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 December 31, 2023 or 2022.

Short-Term Investments

Short-Term Investments	12 Months Ended
	Dec. 31, 2023
Investments, Debt and Equity Securities [Abstract]
Short-Term Investments	4. 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 December 31, 2023 U.S. treasury securities 1 or less $ 17,632 $ 18 $ - $ 17,650 Total $ 17,632 $ 18 $ - $ 17,650 December 31, 2022 U.S. treasury securities 1 or less $ 12,006 - ( 90 ) $ 11,916 Total $ 12,006 $ - $ ( 90 ) $ 11,916 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 (loss).

Property and Equipment

Property and Equipment	12 Months Ended
	Dec. 31, 2023
Property, Plant and Equipment [Abstract]
Property and Equipment	5. Property and Equipment Property and equipment consisted of the following (in thousands): December 31, 2023 2022 Furniture & fixtures $ 60 $ 60 Machinery & lab equipment 584 534 Computer equipment 15 26 Leasehold improvements 20 20 Less accumulated depreciation and amortization ( 364 ) ( 249 ) Property and equipment, net $ 315 $ 391 Depreciation expense related to property and equipment was approximately $ 126,000 and $ 118,000 for the years ended December 31, 2023 and 2022, respectively. During the year ended December 31, 2023 and 2022, the Company disposed of fully depreciated property and equipment totaling approximately $ 11,000 and $ 16,000 , respectively. No material gains or losses on the disposal of property and equipment have been recorded for the years ended December 31, 2023 or 2022.

Acquisition

Acquisition	12 Months Ended
	Dec. 31, 2023
Business Combination and Asset Acquisition [Abstract]
Acquisition	6. 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 the 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 consolidated statement of operations and comprehensive loss for the year ended December 31, 2023, or to additional paid-in capital on the 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. Transaction costs of approximately $ 0.4 million associated with the acquisition were included in the Company’s research and development expense during the year ended December 31, 2022. A summary of the purchase price allocation is as follows (in thousands): Amount Assets acquired: Cash $ 700 Prepaid expenses and other current assets 28 Fixed assets 6 Total assets acquired 734 Liabilities assumed: Accounts payable 265 Accrued expenses 976 Total liabilities assumed 1,241 Net liabilities acquired $ 507 Issuance of common stock for Bioniz acquisition 22,542 Acquired in-process research and development $ 23,049

Leases

Leases	12 Months Ended
	Dec. 31, 2023
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 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, were $ 0.5 million and $ 0.6 million for the years ended December 31, 2023 and 2022, respectively. The Company records its right-of-use-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 year ended December 31, 2023, is as follows (in thousands, except lease term and discount rate): December 31, 2023 Balance sheet information Right-of-use assets $ 796 Lease liabilities, current $ 440 Lease liabilities, non-current 384 Total lease liabilities $ 824 Other information Weighted average remaining lease term 2.28 years Weighted average discount rate 8.25 % Supplemental cash flow information Operating cash outflows from operating leases $ 499 Right-of-use assets obtained in exchange for lease obligations $ — Maturities of lease liabilities as of December 31, 2023, were as follows (in thousands): Year ending December 31, 2024 $ 492 2025 219 2026 169 2027 28 Total undiscounted lease payments 908 Less: imputed interest ( 84 ) Total lease liabilities $ 824 As of December 31, 2023, the Company does not have any leases that have not yet commenced that create significant rights and obligations.

Accrued Expenses

Accrued Expenses	12 Months Ended
	Dec. 31, 2023
Accrued Liabilities, Current [Abstract]
Accrued Expenses	8. Accrued Expenses Accrued expenses consisted of the following (in thousands): December 31, 2023 2022 Accrued payroll and other employee benefits $ 3,054 $ 2,975 Clinical development 2,265 3,253 Non-clinical research 947 465 Other accruals 431 472 Accrued interest - 74 Total accrued expenses $ 6,697 $ 7,239

Partnerships

Partnerships	12 Months Ended
	Dec. 31, 2023
Collaboration And License Agreement [Abstract]
Partnerships	9. 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 $ 33.1 million based on the currency exchange rate quoted by MUFG Bank, Ltd. on March 21, 2024. The Company is also eligible to receive up to $ 101.4 million upon the achievement of certain development and commercialization milestones. 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 three months following the delivery of topline data from the EQUALISE clinical study in lupus nephritis and interim data from the EQUATOR Phase 3 clinical study in acute graft-versus-host disease. 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 costs incurred as a percentage of the estimated total costs expected to be incurred over the expected term of the research and development services. Reimbursable research and development costs will be recognized as revenue as incurred. The Company recognized revenue of $ 36.1 million and $ 15.8 million under the Asset Purchase Agreement during the years ended December 31, 2023 and 2022, respectively. Such revenue was comprised of $ 27.0 million associated with development funding and $ 9.1 million associated with the amortization of the upfront payment during the year ended December 31, 2023. Such revenue was comprised of $ 11.8 million associated with development funding and $ 4.0 million associated with the amortization of the upfront payment during the year ended December 31, 2022. As of December 31, 2023, aggregate deferred revenue related to the Asset Purchase Agreement was $ 15.7 million, which was all classified as current on the consolidated balance sheet. As of December 31, 2023, the Company has received $ 38.0 million in cash related to aggregate development funding payments 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 addition, the Company has agreed to co-fund an ongoing Phase 2 clinical study of itolizumab in subjects with ulcerative colitis being conducted by Biocon in India. 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 December 31, 2023, the Company has not made or received payments in connection with the milestones or royalties within the agreement.

Notes Payable

Notes Payable	12 Months Ended
	Dec. 31, 2023
Debt Disclosure [Abstract]
Notes Payable	10 . 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 represents the maximum amount the Company is 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 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 the 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 due and owing 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. As of December 31, 2023, the Company had no further obligations under the Loan Agreement. The aggregate carrying amounts of the Term Loan is comprised of the following (in thousands): December 31, 2023 2022 Principal $ - $ 8,571 Add: accreted liability for final payment fee - 430 Less: unamortized discount - ( 48 ) Total $ - $ 8,953

Stockholders_ Equity

Stockholders’ Equity	12 Months Ended
	Dec. 31, 2023
Equity [Abstract]
Stockholders’ Equity	11. Stockholders’ Equity As of December 31, 2023, 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 35,254,752 and 34,414,149 shares of common stock outstanding as of December 31, 2023 and 2022, respectively. 2023 ATM Facility In October 2023, we entered into an at-the-market facility with Jefferies LLC, or Jefferies, under which we may offer and sell shares of our common stock having an aggregate offering price of up to $ 21.95 million from time to time through Jefferies acting as our sales agent, or the 2023 ATM Facility. As of the filing of this Annual Report on form 10-K, we have 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 December 31, 2023, the Company has 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 the Company’s common stock under the stock repurchase program since December 31, 2023 and through the date of the filing of this Annual Report on Form 10-K. 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. 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 Equity Incentive Plan (the 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 year ended December 31, 2023, the Company recognized incremental stock-based compensation expense totaling $ 0.3 million associated with the repricing which is included in general and administrative and research and development expense on the consolidated statement of operations and comprehensive loss. 2018 Equity Incentive Plan In October 2018, the Company adopted the 2018 Equity Incentive Plan (the 2018 Plan) which replaced the Company’s legacy 2017 Equity Incentive Plan (the 2017 Plan). The 2018 Plan provides for the grant of incentive stock options, non-statutory stock options, stock appreciation rights, restricted stock awards, restricted stock unit awards, performance stock awards, performance cash awards and other forms of stock awards. As of December 31, 2023, the 2018 Plan had a maximum of 576,464 total shares available for issuance. The number of shares of common stock reserved for issuance under the 2018 Plan will automatically increase on January 1 of each calendar year through January 1, 2028, in an amount equal to 5.0% of the total number of shares of the Company’s capital stock outstanding on the last day of the calendar month before the date of each automatic increase, or a lesser number of shares determined by the Board. Options granted under the 2018 Plan are exercisable at various dates as determined upon grant and will expire no more than ten years from their date of grant. The exercise price of each option shall be determined by the Board based on the estimated fair value of the Company’s stock on the date of the option grant. The exercise price shall not be less than 100 % of the fair market value of the Company’s common stock at the time the option is granted. Most option grants generally vest 25 % on the first anniversary of the original vesting commencement date, with the balance vesting monthly over the remaining three years . Stock Options The following summarizes stock option activity for the year ended December 31, 2023: Outstanding Options Weighted- Weighted Aggregate (a) Balances as of December 31, 2022 5,102,501 $ 4.11 Granted 2,446,300 $ 0.99 Exercised - $ - Forfeitures and cancellations ( 517,726 ) $ 2.17 Balances as of December 31, 2023 (b) 7,031,075 $ 0.90 7.57 $ 27 Options exercisable as of December 31, 2023 (b) 3,737,311 $ 1.01 6.63 $ 5 (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 December 31, 2023, of $ 0.72 and the price of the underlying options. (b) The weighted -average exercise price per share of the options outstanding and exercisable as of December 31, 2023, includes the impact of the repricing of 6,628,589 options on August 14, 2023, at $ 0.785 per share. There were no stock options exercised for the years ended December 31, 2023 and 2022. The fair value of stock options that vested in the years ended December 31, 2023 and 2022 was $ 4.1 million and $ 4.5 million, respectively. The weighted-average grant-date fair value of options granted was $ 0.69 and $ 2.49 for the years ended December 31, 2023 and 2022, respectively. As of December 31, 2023, unrecognized compensation expense related to unvested stock options was $ 5.3 million and is expected to be recognized over a weighted-average period of 2.52 years. 2018 Employee Stock Purchase Plan In October 2018, the Company adopted the 2018 Equity Stock Purchase Plan (ESPP) whereby eligible employees may elect to withhold up to 15 % of their earnings to purchase shares of the Company’s common stock at a price per share equal to the lower of (i) 85 % of the fair market value of a share of the Company’s common stock on the first date of an offering or (ii) 85 % of the fair market value of a share of the Company’s common stock on the date of the purchase right (purchase right). Initially, 343,275 shares of the Company’s common stock were approved for issuance under the ESPP pursuant to purchase rights granted to the Company’s employees or to employees of any of the Company’s designated affiliates. The number of shares of the Company’s common stock reserved for issuance will automatically increase on January 1 of each calendar year through January 1, 2028, by the lesser of (1) 1.0% of the total number of shares of the Company’s common stock outstanding on the last day of the calendar month before the date of the automatic increase, and (2) 343,275 shares; provided that before the date of any such increase, the Board may determine that such increase will be less than the amount set forth in clauses (1) and (2) . As of December 31, 2023, the Company had issued 597,272 shares of common stock under the ESPP, 289,855 of which were issued during the year ended December 31, 2023. The Company had 979,383 shares available for future issuance under the ESPP as of December 31, 2023. Stock-based Compensation Expense Total non-cash stock-based compensation expense for all stock awards and purchase rights, net of forfeitures recognized as they occur, that was recognized in the consolidated statement of operations is as follows (in thousands): Year Ended 2023 2022 Research and development $ 1,549 $ 1,799 General and administrative 2,448 3,042 Total $ 3,997 $ 4,841 The weighted-average assumptions used in the Black-Scholes option pricing model to determine the fair value of the employee and nonemployee stock option grants were as follows: Year Ended 2023 2022 Risk-free interest rate 3.93 % 1.93 % Expected volatility 78.22 % 81.60 % Expected term (in years) 6.04 5.84 Expected dividend yield 0 % 0 % Risk-free interest rate. The risk-free rate assumption is based on the U.S. Treasury instruments, the terms of which were consistent with the expected term of the Company’s stock options. Expected volatility. Due to the Company’s limited operating history and lack of company-specific historical or implied volatility as a private company, the expected volatility assumption was determined by examining the historical volatilities of a group of industry peers whose share prices are publicly available. Expected term. The expected term of stock options represents the weighted-average period the stock options are expected to be outstanding. The Company uses the simplified method for estimating the expected term as provided by the SEC. The simplified method calculates the expected term as the average of the time-to-vesting and the contractual life of the options. Expected dividend yield. The expected dividend assumption is based on the Company’s history and expectation of dividend payouts. The Company has not paid and does no t intend to pay dividends. Forfeitures . The Company reduces stock-based compensation expense for actual forfeitures during the period. Common Stock Reserved for Future Issuance Common stock reserved for future issuance consists of the following as of December 31, 2023 and 2022: December 31, 2023 2022 Stock options issued and outstanding 7,031,075 5,102,501 Warrants for common stock 1,366,141 1,366,141 Awards available under the 2018 Equity Incentive Plan 576,464 784,331 Employee stock purchase plan 979,383 925,963 Total 9,953,063 8,178,936

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2023
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	12. Commitments and Contingencies Leases and Other Commitments As of December 31, 2023, the Company leased certain office and laboratory space in La Jolla, California under non-cancelable operating leases, including a lease for laboratory space that expires in February 2025 and leases for office space that expire in February 2027. The Company previously leased office space in South San Francisco, California under a lease that expired in February 2023. The Company enters into service agreements with indemnification clauses in the ordinary course of business. Pursuant to such clauses, the Company indemnifies, defends, holds harmless, and agrees to reimburse the indemnified party for losses suffered or incurred by third party claims arising out of the indemnified party’s performance of service. The Company has not incurred costs to defend lawsuits pursuant to these indemnification clauses. Litigation As of December 31, 2023, there was no litigation against the Company.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2023
Income Tax Disclosure [Abstract]
Income Taxes	13. Income Taxes The components of loss before income tax provision (benefit) for the years ended December 31, 2023 and 2022 consisted of the following (in thousands): Year Ended 2023 2022 U.S. ( 7,659 ) ( 60,403 ) Foreign ( 5,096 ) ( 2,025 ) $ ( 12,755 ) $ ( 62,428 ) During the year ended December 31, 2023, the Company recorded a current federal tax expense of $ 564,000 and a current state expense of $ 16,000 . The Company has no t recorded a current or deferred tax expense or benefit for the year ended December 31, 2022. The following is a reconciliation of the expected statutory federal income tax provision to our actual income tax provision for the years ended December 31, 2023 and 2022 (in thousands): Year Ended 2023 2022 Income taxes at statutory rates $ ( 2,679 ) $ ( 13,110 ) State income tax, net of federal benefit 1,802 ( 1,681 ) Stock-based compensation ( 728 ) 533 Officers compensation 1,379 - Permanent items 55 95 Research and orphan drug credits ( 619 ) ( 1,493 ) Foreign rate differential 448 243 Acquired in-process research and development - 4,840 Change in valuation allowance 922 10,573 $ 580 $ - The tax effects of temporary differences that give rise to significant portions of the deferred tax assets and deferred tax liabilities as of December 31, 2023 and 2022 are as follows (in thousands): December 31, 2023 2022 Deferred tax assets: Net operating loss carryforward $ 19,562 $ 28,222 Credits 8,314 9,289 Capitalized research expenditures 4,235 7,086 Deferred revenue 12,748 - Equity compensation 1,801 1,829 Other 781 1,196 Total deferred tax assets 47,441 47,622 Valuation allowance ( 47,213 ) ( 46,317 ) Total deferred tax assets, net of allowance $ 228 $ 1,305 Deferred tax liabilities: Operating lease right-of-use asset ( 167 ) ( 284 ) Deferred revenue - ( 945 ) Other ( 61 ) ( 76 ) Total deferred tax liabilities $ ( 228 ) $ ( 1,305 ) The Company has established a valuation allowance against its net deferred tax assets due to the uncertainty surrounding the realization of such assets. The Company periodically evaluates the recoverability of the deferred tax assets. At such time as it is determined that it is more likely than not that deferred assets are realizable, the valuation allowance will be reduced. The Company has recorded a full valuation allowance of $ 47.2 million as of December 31, 2023 , as it does not believe it is more likely than not that certain deferred tax assets will be realized primarily due to the generation of pre-tax book losses in the current year, the lack of feasible tax-planning strategies, the limited existing taxable temporary differences, and the subjective nature of forecasting future taxable income into the future. The Company increased its valuation allowance by approximately $ 0.9 million during the year ended December 31, 2023. At December 31, 2023 , the Company had federal and California tax loss carryforwards of approximately $ 76.9 million and $ 76.5 million, respectively. The federal net operating loss carryover includes $ 76.9 million of net operating losses generated subsequent to 2017. Federal net operating losses generated after December 31, 2017, carryover indefinitely but the deductibility of such federal net operating losses is limited to 80 % of taxable income. The federal net operating losses of $ 76.9 million were generated after December 31, 2017 and may be carried over indefinitely, but the deductibility of such losses is limited to 80 % of federal taxable income. The state net operating loss carryforwards, begin to expire in 2037 unless previously utilized. The Company has $ 4.8 million of Australian net operating loss carryforwards as of December 31, 2023, that are carried forward indefinitely. At December 31, 2023 , the Company had federal and state tax credit carryforwards of approximately $ 6.1 million and $ 2.8 million, respectively, after reduction for uncertain tax positions. The Company has not performed a formal research and development credit study with respect to these credits. The federal credits will begin to expire in 2040 , if unused, and the state credits carryforward indefinitely. 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 completed an ownership change analysis through June 30, 2023, pursuant to IRC Section 382 and determined that the Company’s ability to offset taxable income in 2023 is not expected to be impacted by ownership changes occurring prior to that date. If ownership changes within the meaning of IRC Section 382 occur in the future, 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 following table summarizes the reconciliation of the unrecognized tax benefits activity during the years ended December 31, 2023 and 2022 (in thousands): Year Ended 2023 2022 Unrecognized tax benefits – beginning $ 5,879 $ 5,487 Gross increases – tax positions in prior period 83 - Gross decreases – tax positions in prior period - - Gross increase – current-period tax positions 113 392 Gross decrease – current-period tax positions - - Settlements - - Lapse of statute of limitations - - Unrecognized tax benefits – ending $ 6,075 $ 5,879 The unrecognized tax benefit amounts are reflected in the determination of the Company’s deferred tax assets. If recognized, none of these amounts would affect the Company’s effective tax rate, since it would be offset by an equal corresponding adjustment in the deferred tax asset valuation allowance. The Company does not foresee material changes to its liability for uncertain tax benefits within the next twelve months. The Company’s policy is to recognize interest and/or penalties related to income tax matters in income tax expense. The Company had no accrual for interest or penalties on the Company's consolidated balance sheet as of December 31, 2023, and has not recognized interest and/or penalties in the consolidated statement of operations for the year ended December 31, 2023. All tax years for both federal and state purposes remain open and subject to examination by tax jurisdictions. The Company is subject to taxation in the United States, various U.S. state jurisdictions and Australia. The 2017 tax reform act amended the IRC, effective for amounts paid or incurred in tax years beginning after December 31, 2021, to eliminate the immediate expensing of research and experimental (R&E) expenditures and 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 years ( 15 years for expenditures attributable to foreign research). Income tax expense was $ 0.6 million for the year ended December 31, 2023. 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. There was no income tax expense for the year ended December 31, 2022.

Retirement Plan

Retirement Plan	12 Months Ended
	Dec. 31, 2023
Retirement Benefits [Abstract]
Retirement Plan	14. Retirement Plan The Company sponsors an employee savings plan that qualifies as a deferred salary arrangement under Section 401(k) of the IRC. Participating employees may defer up to the Internal Revenue Service annual contribution limit. The Company did no t make any contributions for the years ended December 31, 2023 or 2022.

Subsequent Events

Subsequent Events	12 Months Ended
	Dec. 31, 2023
Subsequent Events [Abstract]
Subsequent Events	15. Subsequent Events On March 6, 2024, upon the recommendation of the Compensation Committee of the Board, the Board 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 Board 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 Plan.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2023
Accounting Policies [Abstract]
Recently Issued and Recently Adopted Accounting Pronouncements	Recently Issued and Recently 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 accounting standards update will be effective for the Company beginning in the first quarter of fiscal 2024. The Company does not expect this accounting standards update to have a material impact on its 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 consolidated financial statements. No other new accounting pronouncements or legislation issued or effective as of December 31, 2023 have had, or are expected to have, a material impact on our consolidated financial statements.
Use of Estimates	Use of Estimates The preparation of the Company’s 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 consolidated financial statements and accompanying notes. Significant estimates in the Company’s consolidated financial statements relate to accrued research and development expense, 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 Risk 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 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 Income (Loss) The Company is required to report all components of comprehensive loss, including net loss, in the 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 December 31, 2023 and 2022, 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 9). Reimbursable costs that have not been invoiced as of the balance sheet date are recorded as unbilled accounts receivable. As of December 31, 2023, and 2022, the Company had unbilled accounts receivable totaling $ 3.7 million and $ 2.8 million, respectively, classified as accounts receivable on its 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 each of December 31, 2023, and 2022, 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): December 31, 2023 2022 Australian research and development tax incentive $ 2,054 $ 1,006 Prepaid clinical development 1,008 449 Prepaid insurance 532 709 Other receivables 497 269 Prepaid other 422 433 Other current assets 235 8 Total prepaid expenses and other current assets $ 4,748 $ 2,874
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	Leases 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 operating 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 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 development 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 consolidated balance sheet.
Australian Research and Development Tax Incentive	Australian Research and Development Tax Incentive The Company is eligible under the Australian Research and Development Tax Incentive Program, or the Tax Incentive, to obtain a cash refund from the Australian Taxation Office for eligible research and development expenditures. To be eligible, the filing entity must have revenue of less than AUD $ 20.0 million during the reimbursable period and cannot be controlled by income tax exempt entities. The Tax Incentive is recognized as a reduction to research and development expense when there is reasonable assurance that the Tax Incentive will be received, the relevant expenditure has been incurred, and the amount can be reliably measured. The Company classifies its estimate for the Tax Incentive as prepaid expenses and other current assets on the accompanying consolidated balance sheet. As of December 31, 2023 and 2022, the Company recorded $ 2.1 million and $ 1.0 million within prepaid expenses 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 contract 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 consolidated balance sheet net of an allowance for credit losses. The Company's contract assets includes trade accounts receivables from the Ono Asset Purchase Agreement (see Note 9). Reimbursable costs that have not been invoiced as of the balance sheet date are recorded as unbilled accounts receivable. As of December 31, 2023 and 2022, the Company had unbilled accounts receivable totaling $ 3.7 million and $ 2.8 million, respectively, classified as accounts receivable on its consolidated balance sheet.
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 consolidated balance sheet. The noncurrent portion of deferred revenue is included and separately disclosed in the Company’s consolidated balance sheet.
Acquired In-Process Research and Development Expense	Acquired In-Process Research and Development 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 development 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, and regulatory costs including those related to preparing and filing INDs with the FDA. Research and development costs are expensed as incurred.
Patent Costs	Patent Costs The Company expenses all costs as incurred in connection with patent applications (including direct application fees, and the legal and consulting expenses related to making such applications) and such costs are included in general and administrative expenses in the consolidated statement of operations.
Stock-Based Compensation	Stock-based Compensation The Company measures employee and nonemployee stock-based awards, including stock options and 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	Income 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 consolidated financial statements. Under this method, deferred tax assets and liabilities are determined on the basis of the differences between the 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 completed an ownership change analysis through June 30, 2023 pursuant to IRC Section 382 and determined that the Company’s ability to offset taxable income in 2023 is not expected to be impacted by ownership changes occurring prior to that date. If ownership changes within the meaning of IRC Section 382 occur in the future, 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 Loss per Share	Net Loss per Share Basic net loss per share is calculated by dividing the net loss by the weighted-average number of common shares outstanding for the period. Diluted net loss per share is computed by dividing the net loss by the weighted average number of common shares and common share equivalents outstanding for the period. Common stock equivalents are only included when their effect is dilutive. The Company’s potentially dilutive securities include outstanding options under the Company’s equity incentive plan and outstanding warrants to purchase common stock, each of which have been excluded from the computation of diluted net loss per share as they would be anti-dilutive to the net loss per share. For all periods presented, there is no difference in the number of shares used to calculate basic and diluted shares outstanding due to the Company’s net loss position. Potentially dilutive securities not included in the calculation of diluted net loss per share attributable to common stockholders because to do so would be anti-dilutive are as follows (in common stock equivalent shares): Year Ended 2023 2022 Common stock options 7,031,075 5,102,501 Common stock warrants 1,366,141 1,366,141 Total 8,397,216 6,468,642

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2023
Accounting Policies [Abstract]
Schedule of Prepaid Expenses and Other Current Assets	Prepaid expenses and other current assets consisted of the following (in thousands): December 31, 2023 2022 Australian research and development tax incentive $ 2,054 $ 1,006 Prepaid clinical development 1,008 449 Prepaid insurance 532 709 Other receivables 497 269 Prepaid other 422 433 Other current assets 235 8 Total prepaid expenses and other current assets $ 4,748 $ 2,874
Summary of Potentially Dilutive Securities Not Included in Calculation of Diluted Net Loss Per Share	Potentially dilutive securities not included in the calculation of diluted net loss per share attributable to common stockholders because to do so would be anti-dilutive are as follows (in common stock equivalent shares): Year Ended 2023 2022 Common stock options 7,031,075 5,102,501 Common stock warrants 1,366,141 1,366,141 Total 8,397,216 6,468,642

Fair Value of Financial Instr_2

Fair Value of Financial Instruments (Tables)	12 Months Ended
	Dec. 31, 2023
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 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 $ - $ - Fair Value Measurements Using Quoted Prices in Significant Significant Active Markets Other Unobservable December 31, for Identical Observable Inputs 2022 Assets (Level 1) Inputs (Level 2) (Level 3) Short-term investments: U.S. treasury securities $ 11,916 $ 11,916 $ - $ - Total $ 11,916 $ 11,916 $ - $ -

Short-Term Investments (Tables)

Short-Term Investments (Tables)	12 Months Ended
	Dec. 31, 2023
Investments, Debt and Equity Securities [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 December 31, 2023 U.S. treasury securities 1 or less $ 17,632 $ 18 $ - $ 17,650 Total $ 17,632 $ 18 $ - $ 17,650 December 31, 2022 U.S. treasury securities 1 or less $ 12,006 - ( 90 ) $ 11,916 Total $ 12,006 $ - $ ( 90 ) $ 11,916

Property and Equipment (Tables)

Property and Equipment (Tables)	12 Months Ended
	Dec. 31, 2023
Property, Plant and Equipment [Abstract]
Schedule of Property and Equipment	Property and equipment consisted of the following (in thousands): December 31, 2023 2022 Furniture & fixtures $ 60 $ 60 Machinery & lab equipment 584 534 Computer equipment 15 26 Leasehold improvements 20 20 Less accumulated depreciation and amortization ( 364 ) ( 249 ) Property and equipment, net $ 315 $ 391

Acquisition (Tables)

Acquisition (Tables)	12 Months Ended
	Dec. 31, 2023
Business Combination and Asset Acquisition [Abstract]
Summary of Purchase Price Allocation	A summary of the purchase price allocation is as follows (in thousands): Amount Assets acquired: Cash $ 700 Prepaid expenses and other current assets 28 Fixed assets 6 Total assets acquired 734 Liabilities assumed: Accounts payable 265 Accrued expenses 976 Total liabilities assumed 1,241 Net liabilities acquired $ 507 Issuance of common stock for Bioniz acquisition 22,542 Acquired in-process research and development $ 23,049

Leases (Tables)

Leases (Tables)	12 Months Ended
	Dec. 31, 2023
Leases [Abstract]
Summary of Additional Information Related to Leases	Additional information related to the Company’s leases as of and for the year ended December 31, 2023, is as follows (in thousands, except lease term and discount rate): December 31, 2023 Balance sheet information Right-of-use assets $ 796 Lease liabilities, current $ 440 Lease liabilities, non-current 384 Total lease liabilities $ 824 Other information Weighted average remaining lease term 2.28 years Weighted average discount rate 8.25 % Supplemental cash flow information Operating cash outflows from operating leases $ 499 Right-of-use assets obtained in exchange for lease obligations $ —
Schedule of Maturities of Lease Liabilities	Maturities of lease liabilities as of December 31, 2023, were as follows (in thousands): Year ending December 31, 2024 $ 492 2025 219 2026 169 2027 28 Total undiscounted lease payments 908 Less: imputed interest ( 84 ) Total lease liabilities $ 824

Accrued Expenses (Tables)

Accrued Expenses (Tables)	12 Months Ended
	Dec. 31, 2023
Accrued Liabilities, Current [Abstract]
Schedule of Accrued Expenses	Accrued expenses consisted of the following (in thousands): December 31, 2023 2022 Accrued payroll and other employee benefits $ 3,054 $ 2,975 Clinical development 2,265 3,253 Non-clinical research 947 465 Other accruals 431 472 Accrued interest - 74 Total accrued expenses $ 6,697 $ 7,239

Notes Payable (Tables)

Notes Payable (Tables)	12 Months Ended
	Dec. 31, 2023
Debt Disclosure [Abstract]
Schedule of Aggregate Carrying Amounts of Term Loan	The aggregate carrying amounts of the Term Loan is comprised of the following (in thousands): December 31, 2023 2022 Principal $ - $ 8,571 Add: accreted liability for final payment fee - 430 Less: unamortized discount - ( 48 ) Total $ - $ 8,953

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	12 Months Ended
	Dec. 31, 2023
Equity [Abstract]
Summary of Stock Option Activity	The following summarizes stock option activity for the year ended December 31, 2023: Outstanding Options Weighted- Weighted Aggregate (a) Balances as of December 31, 2022 5,102,501 $ 4.11 Granted 2,446,300 $ 0.99 Exercised - $ - Forfeitures and cancellations ( 517,726 ) $ 2.17 Balances as of December 31, 2023 (b) 7,031,075 $ 0.90 7.57 $ 27 Options exercisable as of December 31, 2023 (b) 3,737,311 $ 1.01 6.63 $ 5 (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 December 31, 2023, of $ 0.72 and the price of the underlying options. (b) The weighted -average exercise price per share of the options outstanding and exercisable as of December 31, 2023, includes the impact of the repricing of 6,628,589 options on August 14, 2023, at $ 0.785 per share.
Summary of Non-cash Stock-based Compensation Expense	Total non-cash stock-based compensation expense for all stock awards and purchase rights, net of forfeitures recognized as they occur, that was recognized in the consolidated statement of operations is as follows (in thousands): Year Ended 2023 2022 Research and development $ 1,549 $ 1,799 General and administrative 2,448 3,042 Total $ 3,997 $ 4,841
Summary of Weighted-Average Assumptions Used to Determine Fair Value of Stock Option Grants	The weighted-average assumptions used in the Black-Scholes option pricing model to determine the fair value of the employee and nonemployee stock option grants were as follows: Year Ended 2023 2022 Risk-free interest rate 3.93 % 1.93 % Expected volatility 78.22 % 81.60 % Expected term (in years) 6.04 5.84 Expected dividend yield 0 % 0 %
Summary of Reserved Shares of Common Stock for Future Issuance	Common stock reserved for future issuance consists of the following as of December 31, 2023 and 2022: December 31, 2023 2022 Stock options issued and outstanding 7,031,075 5,102,501 Warrants for common stock 1,366,141 1,366,141 Awards available under the 2018 Equity Incentive Plan 576,464 784,331 Employee stock purchase plan 979,383 925,963 Total 9,953,063 8,178,936

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2023
Income Tax Disclosure [Abstract]
Summary of Components of Loss Before Income Tax Provision (Benefit)	The components of loss before income tax provision (benefit) for the years ended December 31, 2023 and 2022 consisted of the following (in thousands): Year Ended 2023 2022 U.S. ( 7,659 ) ( 60,403 ) Foreign ( 5,096 ) ( 2,025 ) $ ( 12,755 ) $ ( 62,428 )
Summary of Reconciliation of Expected Statutory Federal Income Tax Provision to Actual Income Tax Provision	The following is a reconciliation of the expected statutory federal income tax provision to our actual income tax provision for the years ended December 31, 2023 and 2022 (in thousands): Year Ended 2023 2022 Income taxes at statutory rates $ ( 2,679 ) $ ( 13,110 ) State income tax, net of federal benefit 1,802 ( 1,681 ) Stock-based compensation ( 728 ) 533 Officers compensation 1,379 - Permanent items 55 95 Research and orphan drug credits ( 619 ) ( 1,493 ) Foreign rate differential 448 243 Acquired in-process research and development - 4,840 Change in valuation allowance 922 10,573 $ 580 $ -
Significant Components of Deferred Tax Assets and Liabilities	The tax effects of temporary differences that give rise to significant portions of the deferred tax assets and deferred tax liabilities as of December 31, 2023 and 2022 are as follows (in thousands): December 31, 2023 2022 Deferred tax assets: Net operating loss carryforward $ 19,562 $ 28,222 Credits 8,314 9,289 Capitalized research expenditures 4,235 7,086 Deferred revenue 12,748 - Equity compensation 1,801 1,829 Other 781 1,196 Total deferred tax assets 47,441 47,622 Valuation allowance ( 47,213 ) ( 46,317 ) Total deferred tax assets, net of allowance $ 228 $ 1,305 Deferred tax liabilities: Operating lease right-of-use asset ( 167 ) ( 284 ) Deferred revenue - ( 945 ) Other ( 61 ) ( 76 ) Total deferred tax liabilities $ ( 228 ) $ ( 1,305 )
Summary of Reconciliation of Unrecognized Tax Benefits	The following table summarizes the reconciliation of the unrecognized tax benefits activity during the years ended December 31, 2023 and 2022 (in thousands): Year Ended 2023 2022 Unrecognized tax benefits – beginning $ 5,879 $ 5,487 Gross increases – tax positions in prior period 83 - Gross decreases – tax positions in prior period - - Gross increase – current-period tax positions 113 392 Gross decrease – current-period tax positions - - Settlements - - Lapse of statute of limitations - - Unrecognized tax benefits – ending $ 6,075 $ 5,879

Organization and Accounting P_2

Organization and Accounting Pronouncements - Additional Information (Details) $ in Millions	12 Months Ended
	Dec. 31, 2023 USD ($)
Organization, Consolidation and Presentation of Financial Statements [Abstract]
State of incorporation	DE
Date of incorporation	Mar. 16, 2017
Cash, Cash equivalents and short-term investments	$ 40.9

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Summary Of Significant Accounting Policies [Line Items]
Research and experimental expenditures capitalized cost amortization period	5 years
Allowance for credit losses	$ 0	$ 0
Prepaid expenses and other current assets tax incentive	$ 2,100	1,000
Cumulative change in ownership percentage	50%
Cumulative change in ownership period	3 years
Accounts receivable	$ 3,735	$ 2,838
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
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
Maximum | Australian Taxation Office | Australian Research and Development Tax Incentive Program
Summary Of Significant Accounting Policies [Line Items]
Revenue for availability of research and development tax incentive	$ 20,000

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Schedule of Prepaid Expenses and Other Current Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Accounting Policies [Abstract]
Australian research and development tax incentive	$ 2,054	$ 1,006
Prepaid clinical development	1,008	449
Prepaid insurance	532	709
Other receivables	497	269
Prepaid other	422	433
Other current assets	235	8
Total prepaid expenses and other current assets	$ 4,748	$ 2,874

Summary of Significant Accoun_6

Summary of Significant Accounting Policies - Summary of Potentially Dilutive Securities Not Included in Calculation of Diluted Net Loss Per Share (Details) - shares	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities not included in calculation of diluted net loss per share	8,397,216	6,468,642
Common Stock Options
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities not included in calculation of diluted net loss per share	7,031,075	5,102,501
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

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	Dec. 31, 2023	Dec. 31, 2022
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total short-term investments	$ 17,650	$ 11,916
U.S. Treasury Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total short-term investments	17,650	11,916
Level 1
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total short-term investments	17,650	11,916
Level 1 | U.S. Treasury Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total short-term investments	$ 17,650	$ 11,916

Fair Value of Financial Instr_4

Fair Value of Financial Instruments - Additional Information (Details) - USD ($)	Dec. 31, 2023	Dec. 31, 2022
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Carrying amount of notes payable		$ 9,000,000
Financial liabilities	$ 0	$ 0

Short-Term Investments - Schedu

Short-Term Investments - Schedule of Company's Short-Term Investments (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	$ 17,632	$ 12,006
Unrealized Gains	18
Unrealized losses		(90)
Short-term investments	17,650	11,916
U.S. Treasury Securities Maturing in One Year or Less
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	17,632	12,006
Unrealized Gains	18
Unrealized losses		(90)
Short-term investments	$ 17,650	$ 11,916
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

Short-Term Investments - Additi

Short-Term Investments - Additional information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Schedule Of Available For Sale Securities [Line Items]
Other than temporary impairment loss investments available for sale securities	$ 0	$ 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

Property and Equipment - Schedu

Property and Equipment - Schedule of Property and Equipment (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Property Plant And Equipment [Line Items]
Less accumulated depreciation and amortization	$ (364)	$ (249)
Property and equipment, net	315	391
Furniture & Fixtures
Property Plant And Equipment [Line Items]
Property and equipment, gross	60	60
Machinery & Lab Equipment
Property Plant And Equipment [Line Items]
Property and equipment, gross	584	534
Computer Equipment
Property Plant And Equipment [Line Items]
Property and equipment, gross	15	26
Leasehold Improvements
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 20	$ 20

Property and Equipment - Additi

Property and Equipment - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Property, Plant and Equipment [Abstract]
Depreciation expense	$ 126,000	$ 118,000
Disposal of property and equipment	11,000	16,000
Gains (losses) on disposal of property and equipment	$ 0	$ 0

Acquisition - Additional Inform

Acquisition - Additional Information (Details) - Bioniz - USD ($) $ in Thousands			12 Months Ended
	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
Transaction costs			$ 400
Maximum
Business Acquisition [Line Items]
Business acquisition, common stock shares issued		5,699,492
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

Acquisition - Summary of Purcha

Acquisition - Summary of Purchase Price Allocation (Details) - Bioniz $ in Thousands	Feb. 14, 2022 USD ($)
Assets acquired:
Cash	$ 700
Prepaid expenses and other current assets	28
Fixed assets	6
Total assets acquired	734
Liabilities assumed:
Accounts payable	265
Accrued expenses	976
Total liabilities assumed	1,241
Net liabilities acquired	507
Issuance of common stock for Bioniz acquisition	22,542
Acquired in-process research and development	$ 23,049

Leases - Additional Information

Leases - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Lessee, Lease, Description [Line Items]
Operating lease expense	$ 0.5	$ 0.6
Laboratory Space
Lessee, Lease, Description [Line Items]
Lease expiration year	2025
Office Space
Lessee, Lease, Description [Line Items]
Lease expiration year	2027
Lease expired date	2023-02

Leases - Summary of Additional

Leases - Summary of Additional Information Related to Leases (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Balance sheet information
Right-of-use assets	$ 796	$ 1,191
Lease liabilities, current	440	408
Lease liabilities, non-current	384	$ 824
Total lease liabilities	$ 824
Other information
Weighted average remaining lease term	2 years 3 months 10 days
Weighted average discount rate	8.25%
Supplemental cash flow information
Operating cash outflows from operating leases	$ 499
Right-of-use assets obtained in exchange for lease obligations	$ 0

Leases - Schedule of Maturities

Leases - Schedule of Maturities of Lease Liabilities (Details) $ in Thousands	Dec. 31, 2023 USD ($)
Lessee, Operating Lease, Liability, to be Paid, Fiscal Year Maturity [Abstract]
2024	$ 492
2025	219
2026	169
2027	28
Total undiscounted lease payments	908
Less: imputed interest	(84)
Total lease liabilities	$ 824

Accrued Expenses - Schedule of

Accrued Expenses - Schedule of Accrued Expenses (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Accrued Liabilities, Current [Abstract]
Accrued payroll and other employee benefits	$ 3,054	$ 2,975
Clinical development	2,265	3,253
Non-clinical research	947	465
Other accruals	431	472
Accrued interest		74
Total accrued expenses	$ 6,697	$ 7,239

Partnerships - Additional Infor

Partnerships - Additional Information (Details) ¥ in Billions	1 Months Ended		12 Months Ended		31 Months Ended
	Dec. 31, 2022 USD ($)	May 31, 2017 USD ($)	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Nov. 30, 2019 shares	Mar. 21, 2024 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]
Deferred revenue current	$ 14,700,000		$ 15,729,000	$ 14,700,000
Recognized revenue			36,084,000	15,759,000
Ono | Asset Purchase Agreement
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
One-time payment receivable, upon exercises the option							$ 33,100,000	¥ 5
Upfront non-refundable and non-creditable payment receivable, upon exchange of option									$ 26,400,000	¥ 3.5
Foreign curreny realized gain	600,000
Upfront payment received	$ 26,400,000
Upfront non-refundable and non-creditable payment invoiced									25,800,000	¥ 3.5
Upfront and non-creditable payment invoiced									25,800,000
Estimated research and development funding									76,800,000
Initial transaction price									102,600,000
Deferred revenue									$ 25,800,000
Deferred revenue current			15,700,000
Proceeds from research and development fees			38,000,000
Recognized revenue			$ 36,100,000	15,800,000
Option period expiry condition			the option period will expire three months following the delivery of topline data from the EQUALISE clinical study in lupus nephritis and interim data from the EQUATOR Phase 3 clinical study in acute graft-versus-host disease.
Ono | Asset Purchase Agreement | Maximum | Subsequent Event
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Eligible to receive payment on achievement of certain development milestones						$ 101,400,000
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		$ 30,000,000
Sales milestone payments		$ 565,000,000
Research and Development Services | Ono | Asset Purchase Agreement
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Recognized revenue			$ 27,000,000	11,800,000
Upfront Payment Amortization | Ono | Asset Purchase Agreement
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Recognized revenue			$ 9,100,000	$ 4,000,000

Notes Payable - Additional Info

Notes Payable - Additional Information (Details)		1 Months Ended		12 Months Ended
	May 25, 2023 USD ($)	May 31, 2021 Installment	Sep. 30, 2019 USD ($) Installment $ / shares shares	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	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%
Long term loan obligation				$ 0	$ 8,953,000
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
Long term loan obligation				$ 0
Debt instrument, final payment fee	$ 500,000
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

Notes Payable - Schedule of Agg

Notes Payable - Schedule of Aggregate Carrying Amounts of Term Loan (Details) - Line of Credit - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Debt Instrument [Line Items]
Principal	$ 0	$ 8,571
Add: accreted liability for final payment fee	0	430
Less: unamortized discount	0	(48)
Total	$ 0	$ 8,953

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Details) - USD ($)		1 Months Ended			12 Months Ended		82 Months Ended
	Aug. 07, 2023	Oct. 31, 2023	Jul. 31, 2023	Oct. 31, 2018	Dec. 31, 2023	Dec. 31, 2022	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					35,254,752	34,414,149	35,254,752
Stock Repurchased During Period, Value					$ 260,000
Share-Based Payment Arrangement, Expense					$ 3,997,000	$ 4,841,000
Number of shares available for issuance					9,953,063	8,178,936	9,953,063
Fair value of stock options vested					$ 4,100,000	$ 4,500,000
Weighted-average grant-date fair value of options granted					$ 0.69	$ 2.49
Unrecognized compensation expense related to unvested stock options					$ 5,300,000		$ 5,300,000
Expected recognition period of unrecognized compensation expense					2 years 6 months 7 days
Dividends paid					$ 0
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
Share-Based Payment Arrangement, Expense	$ 1,300,000
Vested Repricing Option
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-Based Payment Arrangement, Expense					800,000
Unvested Repriced Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-Based Payment Arrangement, Expense					$ 500,000
Common Stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock Repurchased During Period, Shares					298,385
Stock Repurchased During Period, Value			$ 7,500,000		$ 300,000
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
2023 ATM Facility | Common Stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock shares maximum aggregate offering price		$ 21,950,000
Issuance of common stock, Shares					0
General and Administrative and Research and Development Expense | Repriced Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-Based Payment Arrangement, Expense					$ 300,000
2018 Equity Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Repricing of outstanding options					7,031,075	5,102,501	7,031,075
Number of shares available for issuance					576,464		576,464
Equity incentive plan description					The number of shares of common stock reserved for issuance under the 2018 Plan will automatically increase on January 1 of each calendar year through January 1, 2028, in an amount equal to 5.0% of the total number of shares of the Company’s capital stock outstanding on the last day of the calendar month before the date of each automatic increase, or a lesser number of shares determined by the Board.
Stock option exercised					0	0
2018 Equity Incentive Plan | Common Stock Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Minimum options exercise price as percentage of fair market value of common stock					100%
Remaining vesting period					3 years
2018 Equity Incentive Plan | Common Stock Options | Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Award expiration period					10 years
2018 Equity Incentive Plan | Repriced Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Repricing of outstanding options	6,628,589
2018 Equity Incentive Plan | Tranche One | Common Stock Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting percentage					25%
2018 Employee Stock Purchase Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares authorized for issuance under purchase rights granted to employees				343,275
Employee stock purchase plan description					Equity Stock Purchase Plan (ESPP) whereby eligible employees may elect to withhold up to 15% of their earnings to purchase shares of the Company’s common stock at a price per share equal to the lower of (i) 85% of the fair market value of a share of the Company’s common stock on the first date of an offering or (ii) 85% of the fair market value of a share of the Company’s common stock on the date of the purchase right (purchase right). Initially, 343,275 shares of the Company’s common stock were approved for issuance under the ESPP pursuant to purchase rights granted to the Company’s employees or to employees of any of the Company’s designated affiliates. The number of shares of the Company’s common stock reserved for issuance will automatically increase on January 1 of each calendar year through January 1, 2028, by the lesser of (1) 1.0% of the total number of shares of the Company’s common stock outstanding on the last day of the calendar month before the date of the automatic increase, and (2) 343,275 shares; provided that before the date of any such increase, the Board may determine that such increase will be less than the amount set forth in clauses (1) and (2)
Withhold Percentage of employees earnings to purchase shares of common stock				15%
Minimum stock price per share as percentage of fair market value of common stock				85%
Number of shares issued					289,855		597,272
Number of shares available for future issuance under employee stock purchase plan					979,383
2018 Employee Stock Purchase Plan | Purchase Right
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Minimum stock price per share as percentage of fair market value of common stock				85%

Stockholders' Equity - Summary

Stockholders' Equity - Summary of Stock Option Activity (Details) - 2018 Equity Incentive Plan - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of Outstanding Options, Beginning Balance	5,102,501
Number of Outstanding Options, Granted	2,446,300
Number of Outstanding Options, Exercised	0	0
Number of Outstanding Options, Forfeitures and Cancellations	(517,726)
Number of Outstanding Options, Ending Balance	7,031,075	5,102,501
Number of Outstanding Options, Exercisable	3,737,311
Weighted- Average Exercise Price Per Share, Beginning Balance	$ 4.11
Weighted- Average Exercise Price Per Share, Granted	0.99
Exercise price of options per share	0
Weighted- Average Exercise Price Per Share, Forfeitures and Cancellations	2.17
Weighted- Average Exercise Price Per Share, Ending Balance	0.9	$ 4.11
Weighted- Average Exercise Price Per Share, Exercisable	$ 1.01
Weighted Average Remaining Contractual Term, Options Outstanding	7 years 6 months 25 days
Weighted Average Remaining Contractual Term, Options Exercisable	6 years 7 months 17 days
Aggregate Intrinsic Value, Options Outstanding	$ 27
Aggregate Intrinsic Value, Options Exercisable	$ 5

Stockholders' Equity - Summar_2

Stockholders' Equity - Summary of Stock Option Activity (Parenthetical) (Details)	Dec. 31, 2023 $ / shares shares
Impact Repricing
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Repricing of outstanding options | shares	6,628,589
Repricing of outstanding option per share	$ 0.785
Stock Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Closing stock price per share	$ 0.72

Stockholders' Equity - Summar_3

Stockholders' Equity - Summary of Total Non-cash Stock-based Compensation Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total non-cash stock-based compensation expense	$ 3,997	$ 4,841
Research and Development Expense
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total non-cash stock-based compensation expense	1,549	1,799
General and Administrative Expense
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total non-cash stock-based compensation expense	$ 2,448	$ 3,042

Stockholders' Equity - Summar_4

Stockholders' Equity - Summary of Weighted-Average Assumptions Used to Determine Fair Value of Stock Option Grants (Details)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Equity [Abstract]
Risk-free interest rate	3.93%	1.93%
Expected volatility	78.22%	81.60%
Expected term (in years)	6 years 14 days	5 years 10 months 2 days
Expected dividend yield	0%	0%

Stockholders' Equity - Summar_5

Stockholders' Equity - Summary of Common Stock Reserved for Future Issuance (Details) - shares	Dec. 31, 2023	Dec. 31, 2022
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total common stock reserved for future issuance	9,953,063	8,178,936
Stock Options Issued and Outstanding
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total common stock reserved for future issuance	7,031,075	5,102,501
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	576,464	784,331
Employee Stock Purchase Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total common stock reserved for future issuance	979,383	925,963

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Details)	12 Months Ended
	Dec. 31, 2023 USD ($)
Commitments and Contingencies [Line Items]
Litigation expense	$ 0

Income Taxes - Summary of Compo

Income Taxes - Summary of Components of Loss Before Income Tax Provision (Benefit) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Income Tax Disclosure [Abstract]
U.S.	$ (7,659)	$ (60,403)
Foreign	(5,096)	(2,025)
Net loss before income tax expense	$ (12,755)	$ (62,428)

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2018
Tax Credit Carryforward [Line Items]
Current federal tax expense	$ 564,000
Current state expense	16,000
Current income tax expense (benefit)		$ 0
Deferred income tax expense (benefit)		0
Deferred tax assets, Valuation allowance	47,213,000	46,317,000
Increase in valuation allowance	$ 900,000
Federal and state net operating loss carry forwards, Expiration year	2037
Federal net operating loss carryover			$ 76,900,000
Operating loss carryforwards, Limitation of use	Federal net operating losses generated after December 31, 2017, carryover indefinitely but the deductibility of such federal net operating losses is limited to 80% of taxable income.
Tax credit carry forwards	$ 8,314,000	9,289,000
Tax credit carryforward, Expiration year	2040
Cumulative change in ownership percentage	50%
Cumulative change in ownership period	3 years
Research and experimental expenditures capitalized cost amortization period	5 years
Income tax expense	$ 580,000	0
Maximum
Tax Credit Carryforward [Line Items]
Operating loss carryforwards limitation rate on taxable income	80%
Federal
Tax Credit Carryforward [Line Items]
Federal net operating loss carryover	$ 76,900,000
Tax credit carry forwards	$ 6,100,000
Federal | Maximum
Tax Credit Carryforward [Line Items]
Operating loss carryforwards limitation rate on taxable income	80%
Foreign
Tax Credit Carryforward [Line Items]
Research and experimental expenditures capitalized cost amortization period	15 years
State
Tax Credit Carryforward [Line Items]
Tax credit carry forwards	$ 2,800,000
California
Tax Credit Carryforward [Line Items]
Foreign tax loss carry forwards	76,900,000	$ 76,500,000
Australia
Tax Credit Carryforward [Line Items]
Federal net operating loss carryover	$ 4,800,000

Income Taxes - Reconciliation o

Income Taxes - Reconciliation of Expected Statutory Federal Income Tax Provision to Actual Income Tax Provision (Details) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Income Tax Expense (Benefit), Effective Income Tax Rate Reconciliation, Amount [Abstract]
Income taxes at statutory rates	$ (2,679,000)	$ (13,110,000)
State income tax, net of federal benefit	1,802,000	(1,681,000)
Stock-based compensation	(728,000)	533,000
Officers compensation	1,379,000
Permanent items	55,000	95,000
Research and orphan drug credits	619,000	1,493,000
Foreign rate differential	448,000	243,000
Acquired in-process research and development		4,840,000
Change in valuation allowance	922,000	10,573,000
Income tax expense (benefit)	$ 580,000	$ 0

Income Taxes - Summary of Net D

Income Taxes - Summary of Net Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Deferred tax assets:
Net operating loss carryforward	$ 19,562	$ 28,222
Credits	8,314	9,289
Capitalized research expenditures	4,235	7,086
Deferred revenue	12,748
Equity compensation	1,801	1,829
Other	781	1,196
Total deferred tax assets	47,441	47,622
Valuation allowance	(47,213)	(46,317)
Total deferred tax assets, net of allowance	228	1,305
Deferred tax liabilities:
Operating lease right-of-use asset	(167)	(284)
Deferred revenue		(945)
Other	(61)	(76)
Total deferred tax liabilities	$ (228)	$ (1,305)

Income Taxes - Summary of Recon

Income Taxes - Summary of Reconciliation of Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Income Tax Disclosure [Abstract]
Unrecognized tax benefits – beginning	$ 5,879	$ 5,487
Gross increases – tax positions in prior period	83
Gross increase – current-period tax positions	113	392
Unrecognized tax benefits – ending	$ 6,075	$ 5,879

Retirement Plan - Additional In

Retirement Plan - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Retirement Benefits [Abstract]
Employer's matching contributions to 401(k) plan	$ 0	$ 0

Subsequent Events - Additional

Subsequent Events - Additional Information (Details) - shares	Mar. 06, 2024	Dec. 31, 2023	Dec. 31, 2022
Subsequent Event [Line Items]
Number of shares available for issuance		9,953,063	8,178,936
Subsequent Event | 2024 Inducement Plan
Subsequent Event [Line Items]
Number of shares available for issuance	1,500,000