Summary of Significant Accounting Policies	3 Months Ended
Mar. 31, 2026
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies Use of Estimates The preparation of these unaudited condensed consolidated financial statements in conformity with U.S. GAAP requires the Company to make estimates and assumptions that affect the amounts reported in the unaudited condensed consolidated financial statements and accompanying notes. Actual results could differ from those estimates. On an ongoing basis, the Company evaluates its estimates and assumptions, including those related to revenue recognition, the useful lives of property and equipment, the recoverability of long-lived assets, the incremental borrowing rate for leases, and assumptions used for purposes of determining stock-based compensation, income taxes, the fair value of the warrant liability and discount and rebate liabilities, the valuation of embedded derivatives, and the net realizable value of inventory, among others. The Company bases its estimates on historical experience and on various other assumptions that it believes to be reasonable, the results of which form the basis for making judgments about the carrying value of assets and liabilities. Concentration of Credit Risk Financial instruments that potentially expose the Company to concentrations of credit risk consist principally of cash on deposit and investments with multiple financial institutions, the balances of which frequently exceed insured limits, and accounts receivable, which are concentrated amongst a limited number of customers. Investments The Company maintains investment securities that are classified as available-for-sale securities, primarily consisting of U.S. Treasury securities and corporate bonds. In accordance with Financial Accounting Standards Board (“FASB”) Accounting Standards Codification (“ASC”) Topic 825, Financial Instruments, the Company has historically elected the fair value option based on the Company's liquidity needs. For purchases of debt securities in previous periods, applying fair value accounting most accurately represented the Company's investment strategy due to the fact that excess cash was being invested for the purpose of funding future operations. In such circumstances, securities are carried at fair value with unrealized gains and losses included in fair value adjustment related to investments on the unaudited condensed consolidated statements of operations. As of March 31, 2026, and December 31, 2025, the Company held securities under the fair value option with an aggregate fair value of $82.6 million and $176.5 million, respectively, that contained an aggregate unrealized loss of less than $(0.1) million and an aggregate unrealized gain of $0.1 million, respectively, which is included on the unaudited condensed consolidated statements of operations. The Company did not elect to apply the fair value option to individual securities purchased in 2026 due to its strengthening financial position and decreased need for immediate liquidity. For such securities, unrealized gains and losses are included in net unrealized gains (losses) on available-for-sale securities on the unaudited condensed consolidated statements of comprehensive income (loss). Interest income is recognized as earned using an effective yield method giving effect to the amortization of premium and accretion of discount and is based on the economic life of the securities. Interest income is included in interest and other income, net, in the unaudited condensed consolidated statements of operations. As of March 31, 2026, securities for which the fair value option was not elected had an aggregate fair value and amortized cost basis of $58.6 million, with an aggregate unrealized loss of less than $(0.1) million included in the unaudited condensed consolidated statements of comprehensive income (loss). The fair value of these securities, along with those for which the fair value option was elected, are included in the investments, current, and investments, noncurrent, lines on the unaudited condensed consolidated balance sheets. We determined that none of these recently purchased available-for-sale securities were other-than-temporarily impaired as of March 31, 2026. Therefore, we believe that it is more likely than not that the investments will be held until maturity or a forecasted recovery of fair value. For securities held at March 31, 2026, approximately $105.0 million mature within one year and approximately $36.1 million mature in one to three years. Variable Interest Entities The primary beneficiary of a variable interest entity (“VIE”) is required to consolidate the assets and liabilities of the VIE. When the Company obtains a variable interest in another entity, it assesses at the inception of the relationship and upon occurrence of certain significant events whether the entity is a VIE and, if so, whether the Company is the primary beneficiary of the VIE based on its power to direct the activities of the VIE that most significantly impact the VIE's economic performance and the Company's obligation to absorb losses or the rights to receive benefits from the VIE that could potentially be significant to the VIE. To assess whether the Company has the power to direct the activities of the VIE that most significantly impact the VIE's economic performance, the Company considers all the facts and circumstances, including the Company's role in establishing the VIE and the Company's ongoing rights and responsibilities. The assessment includes identifying the activities that most significantly impact the VIE's economic performance and identifying which party, if any, has the power to direct those activities. In general, the parties that make the most significant decisions affecting the VIE (management and members of the Board of Directors) are deemed to have the power to direct the activities of a VIE. To assess whether the Company has the obligation to absorb losses of the VIE or the rights to receive benefits from the VIE that could potentially be significant to the VIE, the Company considers all of its economic interests that are deemed to be variable interests in the VIE. This assessment requires judgment in determining whether these interests, in the aggregate, are considered potentially significant to the VIE. As of March 31, 2026, and December 31, 2025, the Company identified Acer Therapeutics, Inc. (“Acer”) to be the Company's sole interest in a VIE. As Zevra is the final decision maker for all of Acer's research, development, and commercialization of drug candidates that it is producing, the Company directs the activities of Acer that most significantly impact its performance. Therefore, the Company is the primary beneficiary of this VIE for accounting purposes and consolidates the assets and liabilities of the VIE. Gain on Sale of PRV The Company received a transferable rare pediatric disease priority review voucher (“PRV”) in conjunction with the FDA approval of MIPLYFFA. On February 26, 2025, the Company and its subsidiary, Zevra Denmark A/S, entered into an asset purchase agreement with a buyer, pursuant to which the Company agreed to sell the PRV to the buyer for aggregate proceeds of $150.0 million, payable in cash, upon the closing of the sale. On April 1, 2025, the asset sale was consummated and title of the PRV transferred to the buyer, resulting in net proceeds of $148.3 million to the Company. The PRV did not have a carrying value at the time of sale. In accordance with ASC 610-20, Gains and Losses from the Derecognition of Nonfinancial Assets, the net proceeds from the sale were recorded as a gain on sale of PRV in the Company's unaudited condensed consolidated statements of operations in the three months ended June 30, 2025. Revenue Recognition The Company recognizes revenue in accordance with the provisions of ASC 606, Revenue from Contracts with Customers (“ASC 606”) and, as a result, follows the five-step model when recognizing revenue: 1) identifying a contract; 2) identifying the performance obligations; 3) determining the transaction price; 4) allocating the price to the performance obligations; and 5) recognizing revenue when the performance obligations have been fulfilled. Product Revenues, net Net revenues from product sales are recognized at the transaction price when the customer obtains control of the Company's product, which occurs at a point in time, typically upon receipt of the product by the customer. The Company's current single customer for product sales of MIPLYFFA and OLPRUVA is a specialty pharmacy provider. In accordance with ASC 606, the Company recognizes revenue when fulfilling its performance obligation by transferring control of promised goods or services to its customer, in an amount that reflects the consideration that the Company expects to receive in exchange for those goods or services. In determining when the customer obtains control of the product, the Company considers certain indicators, including whether the Company has a present right to payment from the customer, whether title and/or significant risks and rewards of ownership have transferred to the customer and whether customer acceptance has been received. The Company's net revenues represent total revenues adjusted for discounts and allowances, including estimated cash discounts, chargebacks, rebates, returns, copay assistance, data fees and wholesaler fees for services. These adjustments represent variable consideration under ASC 606 and are recorded as a reduction of revenue. These adjustments are established by management as its best estimate based on available information and will be adjusted to reflect known changes in the factors that impact such allowances. Adjustments for variable consideration are determined based on the contractual terms with customers, historical trends, communications with customers and the levels of inventory remaining in the distribution channel, as well as expectations about the market for the product and anticipated introduction of competitive products. All estimated reserve liabilities related to commercial products are recorded within the current portion of discount and rebate liabilities in the unaudited condensed consolidated balance sheets. Expanded Access Program Net revenue includes revenue from the sale of arimoclomol provided for the treatment of NPC under an expanded access program (“EAP”) in France, and in select territories outside Europe. An EAP is a program giving specific patients access to a drug that is not yet approved for commercial sale. Only drugs targeting serious or rare indications and for which there is currently no appropriate treatment are considered for expanded access programs. Further, to be considered for the expanded access program, the drug must have proven efficacy and safety and must either be undergoing price negotiations or seeking marketing approval. In accordance with ASC 606, the Company recognizes revenue when fulfilling its performance obligation under the global EAP by transferring control of promised goods or services to its customer, in an amount that reflects the consideration that the Company expects to receive in exchange for those goods or services. In determining when the customer obtains control of the product, the Company considers certain indicators, including whether the Company has a present right to payment from the customer, whether title and/or significant risks and rewards of ownership have transferred to the customer and whether customer acceptance has been received. Revenue is recognized net of sales deductions, including discounts, rebates, applicable distributor fees, and revenue-based taxes. The French Health Authorities and the manufacturer have agreed to a price for reimbursements under the EAP in France, but the final price depends on the terms and conditions negotiated with the French Health Authorities, following market authorization. Any excess in the price charged by the manufacturer compared to the price agreed with the health authorities once the medicinal product is authorized in France must be repaid. The potential repayment is considered in the clawback liability. An estimate of net revenue and clawback liability are recognized using the ‘expected value’ method. Accounting for net revenue and clawback liability requires determination of the most appropriate method for estimating the expected final price. This estimate also requires assumptions with respect to inputs into the method, including current pricing of comparable marketed products within the rare disease area in France. Management has considered the expected final sales price as well as the price of similar medicinal products. The Company is operating within a rare disease therapeutic area where there is unmet treatment need and hence a limited number of comparable commercialized medicinal products. The limited available relevant market information for directly comparable commercialized medicines within rare disease increases the uncertainty in management's estimate. Licensing Agreements The terms of the Company’s licensing agreements typically include one or more of the following: (i) upfront fees; (ii) milestone payments related to the achievement of development, regulatory, or commercial goals; and (iii) royalties on net sales of licensed products. Each of these payments may result in licensing revenues. As part of the accounting for these agreements, the Company must develop estimates and assumptions that require judgment to determine the underlying stand-alone selling price for each performance obligation, which determines how the transaction price is allocated among the performance obligations. Generally, the estimation of the stand-alone selling price may include such estimates as independent evidence of market price, forecasted revenues or costs, development timelines, discount rates, and probability of regulatory success. The Company evaluates each performance obligation to determine if it can be satisfied at a point in time or over time, and it measures the services delivered to the licensee, which are periodically reviewed based on the progress of the related program. The effect of any change made to an estimated input component and, therefore, revenue or expense recognized, would be recorded as a change in estimate. In addition, variable consideration (e.g., milestone payments) must be evaluated to determine if it is constrained and, therefore, excluded from the transaction price. Upfront Fees: If a license to the Company’s intellectual property is determined to be distinct from the other performance obligations identified in the arrangement, the Company recognizes revenues from the transaction price allocated to the license when the license is transferred to the licensee and the licensee is able to use and benefit from the license. For licenses that are bundled with other promises, the Company utilizes judgment to assess the nature of the combined performance obligation to determine whether the combined performance obligation is satisfied over time or at a point in time. Milestone Payments: At the inception of each arrangement that includes milestone payments (variable consideration), the Company evaluates whether the milestones are considered probable of being reached and estimates the amount to be included in the transaction price using the most likely amount method. If it is probable that a significant revenue reversal would not occur, the associated milestone value is included in the transaction price. Milestone payments that are not within the Company’s or the licensee’s control, such as non-operational developmental and regulatory approvals, are generally not considered probable of being achieved until those approvals are received. At the end of each reporting period, the Company re-evaluates the probability of achievement of milestones that are within its or the licensee’s control, such as operational developmental milestones and any related constraint, and, if necessary, adjusts its estimate of the overall transaction price. Any such adjustments are recorded on a cumulative catch-up basis, which would affect collaboration revenues and earnings in the period of adjustment. Revisions to the Company’s estimate of the transaction price may also result in negative licensing revenues and earnings in the period of adjustment. Acquired IPR&D and Milestones Expenses In an asset acquisition, payments incurred prior to regulatory approval to acquire rights to in-process research and development (“IPR&D”) projects are expensed as acquired IPR&D and milestones expense in the unaudited condensed consolidated statements of operations unless the project has an alternative future use. These costs include upfront and development milestone payments related to R&D collaborations, licensing arrangements, or other asset acquisitions that provide rights to develop, manufacture and/or sell pharmaceutical products. Where contingent development milestone payments are due to third parties, prior to regulatory approval, the payment obligations are expensed when the milestone results are achieved. Regulatory and commercial milestone payments made to third parties subsequent to regulatory approval are capitalized as intangible assets and amortized to intangible asset amortization over the remaining useful life of the related product. Embedded Derivative The Company evaluates its financial instruments to determine if such instruments are derivatives or contain features that qualify as embedded derivatives. For derivative instruments that are bifurcated from a host contract, the Company recognizes them as either assets or liabilities in the unaudited condensed consolidated balance sheets and measures them at fair value. Embedded derivatives are remeasured at each reporting date, with changes in fair value recognized in earnings within loss on derivative liability in the unaudited condensed consolidated statements of operations. The Company initially assesses the probability of triggering events for bifurcated embedded derivatives in determining fair value. The probability is assessed at each reporting period. Inventories The value of inventories is recorded at net realizable value. The Company determines the cost of its inventories, which include amounts related to materials and manufacturing overhead, on a first-in, first-out basis. Inventories that are not expected to be sold within 12 months are classified as inventories, noncurrent. The Company may scale-up and make commercial quantities of its product candidates prior to the date it anticipates that such product will receive final regulatory approval. The scale-up and commercial production of pre-launch inventory involves the risk that such products may not be approved for marketing on a timely basis, or ever. This risk notwithstanding, the Company may scale-up and build pre-launch inventory of products that have not received final regulatory approval when the Company believes such action is appropriate in relation to the commercial value of the product launch opportunity. We capitalize inventory costs associated with our products prior to regulatory approval when, based on management's judgment, future commercialization is considered probable and the future economic benefit is expected to be realized; otherwise, such costs are expensed as research and development. The determination to capitalize inventory costs is based on various factors, including status and expectations of the regulatory approval process, any known safety or efficacy concerns, potential labeling restrictions, and any other impediments to obtaining regulatory approval. The Company had no pre-approval inventory on its unaudited condensed consolidated balance sheets as of March 31, 2026, or December 31, 2025. Inventory used in clinical trials is also expensed as research and development expense when selected for such use. Inventory that can be used in the production of either clinical or commercial products is expensed as research and development costs when identified for use in a clinical manufacturing campaign. The cost of finished goods inventory that is shipped to a customer to support the Company’s patient assistance programs is expensed when those shipments take place. As of March 31, 2026, and December 31, 2025, the Company did not have pre-launch inventory that qualified for capitalization. The Company performs an assessment of the recoverability of capitalized inventory during each reporting period and writes down any excess and obsolete inventory to its net realizable value in the period in which the impairment is first identified. Such impairment charges, should they occur, are recorded as a component of cost of product revenue in the unaudited condensed consolidated statements of operations. The determination of whether inventory costs will be realizable requires the use of estimates by management. If actual market conditions are less favorable than projected by management, additional write downs of inventory may be required. Additionally, the Company’s products are subject to strict quality control and monitoring, which is performed throughout the manufacturing process. In the event that certain batches or units of product do not meet quality specifications, the Company will record a charge to cost of product revenue, to write down any unsaleable inventory to its estimated net realizable value. For the three months ended March 31, 2026, the Company recognized $0.5 million related to write-downs for unsaleable inventory. There was no write-down for unsaleable inventory for the three months ended March 31, 2025. Cost of Product Revenue The components of cost of product revenue are royalties and expenses directly attributable to revenue. To date, the Company has generated revenue from product sales of MIPLYFFA and OLPRUVA, reimbursements received under the global EAP, royalties or net sales milestone payments generated under the AZSTARYS License Agreement, and consulting agreements. Prior to our acquisition of the assets of Orphazyme A/S (“Orphazyme”) in May 2022, Orphazyme had entered into an asset purchase agreement with LadRx Corporation, which was assigned to XOMA (US) LLC, a wholly-owned subsidiary of XOMA Corporation (“XOMA”), in June 2023 (“XOMA License Agreement”). Under the XOMA License Agreement, XOMA is entitled to a mid-single digit percentage royalty with respect to net sales of MIPLYFFA as well as milestone payments based on future potential sales and regulatory milestones. On August 30, 2023, Acer and Relief Therapeutics SA (“Relief”) entered into an exclusive license agreement (the “Relief License Agreement”). Pursuant to the Relief License Agreement, Zevra is obligated to pay royalties of 10% of U.S. net sales of OLPRUVA up to a maximum of $45.0 million, plus specified regulatory milestones, for total payments to Relief of up to $56.5 million. On April 10, 2025, Relief sold the rights to this royalty to Soleus Capital Management L.P. Under the Aquestive Termination Agreement, Aquestive has the right to receive an amount equal to 10% of any value generated by AZSTARYS and any product candidates containing SDX. Accordingly, in connection with the Commave Settlement Agreement, Aquestive receives 10% of the Company's sales proceeds. Accounts and Other Receivables Accounts and other receivables consist of receivables from MIPLYFFA and OLPRUVA product sales, receivables under the AZSTARYS License Agreement, receivables related to the Commave Settlement Agreement, the global EAP, and income tax receivables and other receivables due to the Company. Receivables under the AZSTARYS License Agreement are recorded for amounts due to the Company related to royalties on product sales. Receivables under the global EAP are recorded for revenue from arimoclomol in France and select territories outside of Europe. The Company provides reserves against receivables for estimated losses that may result from a customer's inability to pay. Receivables are evaluated to determine if any reserve or allowance should be recorded based on consideration of the current economic environment, expectations of future economic conditions, specific circumstances and the Company’s own historical collection experience. Amounts determined to be uncollectible are charged or written-off against the reserve. Research and Development Major components of research and development costs include cash compensation, stock-based compensation, depreciation and amortization expense on research and development property and equipment, costs of preclinical studies, clinical trials and related clinical manufacturing, costs of drug development, costs of materials and supplies, facilities cost, overhead costs, regulatory and compliance costs, and fees paid to consultants and other entities that conduct certain research and development activities on the Company’s behalf. Costs incurred in research and development are expensed as incurred. The Company records nonrefundable advance payments it makes for future research and development activities as prepaid expenses. Prepaid expenses are recognized as expense in the unaudited condensed consolidated statements of operations as the Company receives the related goods or services. The Company enters into contractual agreements with third-party vendors who provide research and development, manufacturing, and other services in the ordinary course of business. Some of these contracts are subject to milestone-based invoicing and services are completed over an extended period of time. The Company records liabilities under these contractual commitments when an obligation has been incurred. This accrual process involves reviewing open contracts and purchase orders, communicating with the applicable personnel to identify services that have been performed and estimating the level of service performed and the associated cost when the Company has not yet been invoiced or otherwise notified of actual cost. The majority of the service providers invoice the Company monthly in arrears for services performed. The Company makes estimates of the accrued expenses as of each balance sheet date based on the facts and circumstances known. The Company periodically confirms the accuracy of the estimates with the service providers and make adjustments, if necessary. Patent Costs Patent costs, including related legal costs, are expensed as incurred and recorded within general and administrative expenses on the unaudited condensed consolidated statements of operations. Income Taxes The Company recognizes deferred tax assets and liabilities for the expected future tax consequences of temporary differences between the financial reporting and tax basis of assets and liabilities, as well as for operating loss and tax credit carryforwards. Deferred tax assets and liabilities are measured using the tax rates that are expected to apply to taxable income for the years in which those tax assets and liabilities are expected to be realized or settled. Valuation allowances are recorded to reduce deferred tax assets to the amount the Company believes is more likely than not to be realized. The Company is subject to taxation in the United States (including federal, state, and local jurisdictions) and the Kingdom of Denmark. Generally, the Company is subject to examination by tax jurisdictions from 2021 to 2024 tax years as the statute of limitation (excluding net operating loss carryforwards) are 3 to 4 years in the United States and Kingdom of Denmark. Tax liabilities may arise from interpretations and judgments made by the Company with regard to transfer pricing in the application of the relevant statutes, regulations, tax rulings and case law across the various jurisdictions. The Company uses significant judgment in (1) determining whether the technical merits of tax positions taken in the various jurisdictions are more-likely-than-not to be sustained based on applicable tax law and (2) measuring the related amount of tax liability that qualifies for recognition. The United States federal and state tax jurisdictions can audit the net operating loss carryforwards from the tax years in which the statute of limitation has expired but can only adjust the net operating loss carryforwards. No income tax returns are currently under examination by taxing authorities. Uncertain tax positions are recognized only when the Company believes it is more likely than not that the tax position will be upheld on examination by the taxing authorities based on the merits of the position. The Company recognizes interest and penalties, if any, related to unrecognized income tax uncertainties in income tax expense. On December 22, 2017, the U.S. government enacted H.R. 1, “An Act to provide for reconciliation pursuant to titles II and V of the concurrent resolution on the budget for fiscal year 2018” (“Tax Act”). Effective January 1, 2018, the Tax Act provides for a new global intangible low-taxed income (“GILTI”) provision. Under the GILTI provision, certain foreign subsidiary earnings in excess of an allowable return on the foreign subsidiary’s tangible assets are included in U.S. taxable income. The Company has not recorded any deferred taxes for future GILTI inclusions as any future inclusions are expected to be treated as a period expense. On July 4, 2025, the One Big Beautiful Bill Act (the “OBBB”), which includes a broad range of tax reform provisions, was signed into law in the United States. This includes a net Controlled Foreign Corporation (“CFC”) tested income (“NCTI”) provision, which is an update of the GILTI provision that was effective under H.R. 1. The Company has not recorded any deferred taxes for future NCTI inclusions as any future inclusions are expected to be treated as a period expense. The Company continues to assess the impact of the OBBB but currently does not expect the OBBB to have a material impact on the Company's estimated annual effective tax rate in 2026. Stock-Based Compensation The Company measures and recognizes compensation expense for all stock-based payment awards made to employees, officers and directors based on the estimated fair values of the awards as of the grant date. The Company records the value of the portion of the award that is ultimately expected to vest as expense over the requisite service period. The Company also accounts for equity instruments issued to non-employees using a fair value approach under ASC subtopic 505-50. The Company values equity instruments and stock options granted using the Black-Scholes-Merton (“BSM”) option pricing model. Earnings per Share The Company uses the two-class method to compute net income (loss) per common share because the Company has issued securities, other than common stock, that contractually entitle the holders to participate in dividends and earnings of the Company. The two-class method requires earnings for the period to be allocated between common stock and participating securities based upon their respective rights to receive distributed and undistributed earnings. Holders of each series of the Company’s convertible preferred stock, if applicable, and select warrants are entitled to participate in distributions, when and if declared by the board of directors, that are made to common stockholders and, as a result, are considered participating securities. Segment and Geographic Information Operating segments are defined as components of an enterprise (business activity from which it earns revenue and incurs expenses) for which discrete financial information is available and regularly reviewed by the chief operating decision maker (“CODM”) in deciding how to allocate resources and in assessing performance. The Company’s CODM is its Chief Executive Officer. The Company views its operations and manages its business as a single operating and reporting segment. See Note C for further information. Foreign Currency Assets and liabilities are translated into the reporting currency using the exchange rates in effect on the balance sheet dates. Equity accounts are translated at historical rates, except for the change in retained earnings during the year, which is the result of the income statement translation process. Revenue and expense accounts are translated using the weighted average exchange rate during the period. The cumulative translation adjustments associated with the net assets of foreign subsidiaries are recorded in accumulated other comprehensive income (loss) in the accompanying unaudited condensed consolidated statements of stockholders’ equity. Debt Issuance Costs Debt issuance costs incurred in connection with financing arrangements are recorded as a reduction of the related debt on the unaudited condensed consolidated balance sheets and amortized over the life of the respective financing arrangement using the effective interest method. Warrants The Company accounts for warrants as either equity-classified or liability-classified instruments based on an assessment of the warrant’s specific terms and applicable authoritative guidance in FASB ASC Topic 480, Distinguishing Liabilities from Equity (“ASC 480”) and FASB ASC Topic 815, Derivatives and Hedging (“ASC 815”). The assessment considers whether the warrants are freestanding financial instruments pursuant to ASC 480, meet the definition of a liability pursuant to ASC 480, and whether the warrants meet all of the requirements for equity classification under ASC 815, including whether the warrants are indexed to the Company's own stock and whether the warrant holders could potentially require “net cash settlement” in a circumstance outside of the issuing company’s control, among other conditions for equity classification. This assessment, which requires the use of professional judgment, is conducted at the time of warrant issuance and as of each subsequent quarterly period end date while the warrants are outstanding. For warrants that meet all criteria for equity classification, the warrants are required to be recorded as a component of additional paid-in capital on the unaudited condensed consolidated statements of changes in stockholders’ equity at the time of issuance. For warrants that do not meet all the criteria for equity classification, the warrants are required to be recorded at their initial fair value on the date of issuance, and on each balance sheet date thereafter. Changes in the estimated fair value of the warrants are recognized as a non-cash gain or loss in other expense, net, on the unaudited condensed consolidated statements of operations. The fair value of the warrants was estimated using the BSM option pricing model. New Accounting Pronouncements Recently Adopted In December 2023, the FASB issued Accounting Standards Update (“ASU”) No. 2023-09, Income Taxes (“Topic 740”): Improvements to Income Tax Disclosures. ASU 2023-09 establishes new income tax disclosure requirements in addition to modifying and eliminating certain existing requirements. Under the new guidance, entities must consistently categorize and provide greater disaggregation of information in the reconciliation of the effective tax rate to the statutory tax rate and must also further disaggregate income taxes paid. The Company adopted ASU 2023-09 for the year ended December 31, 2025 using a retrospective approach and included the required disclosures in the Notes to the Consolidated Financial Statements for income taxes. This standard update did not affect the Company’s results of operations. New Accounting Pronouncements Not Yet Adopted In November 2024, the FASB issued ASU No. 2024-03, Income Statement: Reporting Comprehensive Income-Expense Disaggregation Disclosures (“Subtopic 220-40”): Disaggregation of Income Statement Expenses. The new standard requires disclosure of specified information about certain costs and expenses. ASU 2024-03 is effective for fiscal years beginning after December 15, 2026 and for interim periods within fiscal years beginning after December 15, 2027. Early adoption is permitted. The Company is currently evaluating this guidance to determine the impact it may have on its consolidated financial statements disclosures.

On an ongoing basis, the Company evaluates its estimates and assumptions, including those related to revenue recognition, the useful lives of property and equipment, the recoverability of long-lived assets, the incremental borrowing rate for leases, and assumptions used for purposes of determining stock-based compensation, income taxes, the fair value of the warrant liability and discount and rebate liabilities, the valuation of embedded derivatives, and the net realizable value of inventory, among others. The Company bases its estimates on historical experience and on various other assumptions that it believes to be reasonable, the results of which form the basis for making judgments about the carrying value of assets and liabilities.

The Company maintains investment securities that are classified as available-for-sale securities, primarily consisting of U.S. Treasury securities and corporate bonds. In accordance with Financial Accounting Standards Board (“FASB”) Accounting Standards Codification (“ASC”) Topic 825, Financial Instruments, the Company has historically elected the fair value option based on the Company's liquidity needs. For purchases of debt securities in previous periods, applying fair value accounting most accurately represented the Company's investment strategy due to the fact that excess cash was being invested for the purpose of funding future operations. In such circumstances, securities are carried at fair value with unrealized gains and losses included in fair value adjustment related to investments on the unaudited condensed consolidated statements of operations. As of March 31, 2026, and December 31, 2025, the Company held securities under the fair value option with an aggregate fair value of $82.6 million and $176.5 million, respectively, that contained an aggregate unrealized loss of less than $(0.1) million and an aggregate unrealized gain of $0.1 million, respectively, which is included on the unaudited condensed consolidated statements of operations.

The Company did not elect to apply the fair value option to individual securities purchased in 2026 due to its strengthening financial position and decreased need for immediate liquidity. For such securities, unrealized gains and losses are included in net unrealized gains (losses) on available-for-sale securities on the unaudited condensed consolidated statements of comprehensive income (loss).

Interest income is recognized as earned using an effective yield method giving effect to the amortization of premium and accretion of discount and is based on the economic life of the securities. Interest income is included in interest and other income, net, in the unaudited condensed consolidated statements of operations. As of March 31, 2026, securities for which the fair value option was not elected had an aggregate fair value and amortized cost basis of $58.6 million, with an aggregate unrealized loss of less than $(0.1) million included in the unaudited condensed consolidated statements of comprehensive income (loss). The fair value of these securities, along with those for which the fair value option was elected, are included in the investments, current, and investments, noncurrent, lines on the unaudited condensed consolidated balance sheets. We determined that none of these recently purchased available-for-sale securities were other-than-temporarily impaired as of March 31, 2026. Therefore, we believe that it is more likely than not that the investments will be held until maturity or a forecasted recovery of fair value.

The primary beneficiary of a variable interest entity (“VIE”) is required to consolidate the assets and liabilities of the VIE. When the Company obtains a variable interest in another entity, it assesses at the inception of the relationship and upon occurrence of certain significant events whether the entity is a VIE and, if so, whether the Company is the primary beneficiary of the VIE based on its power to direct the activities of the VIE that most significantly impact the VIE's economic performance and the Company's obligation to absorb losses or the rights to receive benefits from the VIE that could potentially be significant to the VIE.

To assess whether the Company has the power to direct the activities of the VIE that most significantly impact the VIE's economic performance, the Company considers all the facts and circumstances, including the Company's role in establishing the VIE and the Company's ongoing rights and responsibilities. The assessment includes identifying the activities that most significantly impact the VIE's economic performance and identifying which party, if any, has the power to direct those activities. In general, the parties that make the most significant decisions affecting the VIE (management and members of the Board of Directors) are deemed to have the power to direct the activities of a VIE.

This assessment requires judgment in determining whether these interests, in the aggregate, are considered potentially significant to the VIE. As of March 31, 2026, and December 31, 2025, the Company identified Acer Therapeutics, Inc. (“Acer”) to be the Company's sole interest in a VIE. As Zevra is the final decision maker for all of Acer's research, development, and commercialization of drug candidates that it is producing, the Company directs the activities of Acer that most significantly impact its performance. Therefore, the Company is the primary beneficiary of this VIE for accounting purposes and consolidates the assets and liabilities of the VIE.

The Company received a transferable rare pediatric disease priority review voucher (“PRV”) in conjunction with the FDA approval of MIPLYFFA. On February 26, 2025, the Company and its subsidiary, Zevra Denmark A/S, entered into an asset purchase agreement with a buyer, pursuant to which the Company agreed to sell the PRV to the buyer for aggregate proceeds of $150.0 million, payable in cash, upon the closing of the sale. On April 1, 2025, the asset sale was consummated and title of the PRV transferred to the buyer, resulting in net proceeds of $148.3 million to the Company. The PRV did not have a carrying value at the time of sale. In accordance with ASC 610-20, Gains and Losses from the Derecognition of Nonfinancial Assets, the net proceeds from the sale were recorded as a gain on sale of PRV in the Company's unaudited condensed consolidated statements of operations in the three months ended June 30, 2025.

The Company recognizes revenue in accordance with the provisions of ASC 606, Revenue from Contracts with Customers (“ASC 606”) and, as a result, follows the five-step model when recognizing revenue: 1) identifying a contract; 2) identifying the performance obligations; 3) determining the transaction price; 4) allocating the price to the performance obligations; and 5) recognizing revenue when the performance obligations have been fulfilled.

In accordance with ASC 606, the Company recognizes revenue when fulfilling its performance obligation by transferring control of promised goods or services to its customer, in an amount that reflects the consideration that the Company expects to receive in exchange for those goods or services. In determining when the customer obtains control of the product, the Company considers certain indicators, including whether the Company has a present right to payment from the customer, whether title and/or significant risks and rewards of ownership have transferred to the customer and whether customer acceptance has been received. The Company's net revenues represent total revenues adjusted for discounts and allowances, including estimated cash discounts, chargebacks, rebates, returns, copay assistance, data fees and wholesaler fees for services. These adjustments represent variable consideration under ASC 606 and are recorded as a reduction of revenue. These adjustments are established by management as its best estimate based on available information and will be adjusted to reflect known changes in the factors that impact such allowances. Adjustments for variable consideration are determined based on the contractual terms with customers, historical trends, communications with customers and the levels of inventory remaining in the distribution channel, as well as expectations about the market for the product and anticipated introduction of competitive products. All estimated reserve liabilities related to commercial products are recorded within the current portion of discount and rebate liabilities in the unaudited condensed consolidated balance sheets.

Net revenue includes revenue from the sale of arimoclomol provided for the treatment of NPC under an expanded access program (“EAP”) in France, and in select territories outside Europe. An EAP is a program giving specific patients access to a drug that is not yet approved for commercial sale. Only drugs targeting serious or rare indications and for which there is currently no appropriate treatment are considered for expanded access programs. Further, to be considered for the expanded access program, the drug must have proven efficacy and safety and must either be undergoing price negotiations or seeking marketing approval.

In accordance with ASC 606, the Company recognizes revenue when fulfilling its performance obligation under the global EAP by transferring control of promised goods or services to its customer, in an amount that reflects the consideration that the Company expects to receive in exchange for those goods or services. In determining when the customer obtains control of the product, the Company considers certain indicators, including whether the Company has a present right to payment from the customer, whether title and/or significant risks and rewards of ownership have transferred to the customer and whether customer acceptance has been received. Revenue is recognized net of sales deductions, including discounts, rebates, applicable distributor fees, and revenue-based taxes.

The French Health Authorities and the manufacturer have agreed to a price for reimbursements under the EAP in France, but the final price depends on the terms and conditions negotiated with the French Health Authorities, following market authorization. Any excess in the price charged by the manufacturer compared to the price agreed with the health authorities once the medicinal product is authorized in France must be repaid. The potential repayment is considered in the clawback liability. An estimate of net revenue and clawback liability are recognized using the ‘expected value’ method. Accounting for net revenue and clawback liability requires determination of the most appropriate method for estimating the expected final price. This estimate also requires assumptions with respect to inputs into the method, including current pricing of comparable marketed products within the rare disease area in France. Management has considered the expected final sales price as well as the price of similar medicinal products. The Company is operating within a rare disease therapeutic area where there is unmet treatment need and hence a limited number of comparable commercialized medicinal products. The limited available relevant market information for directly comparable commercialized medicines within rare disease increases the uncertainty in management's estimate.

As part of the accounting for these agreements, the Company must develop estimates and assumptions that require judgment to determine the underlying stand-alone selling price for each performance obligation, which determines how the transaction price is allocated among the performance obligations. Generally, the estimation of the stand-alone selling price may include such estimates as independent evidence of market price, forecasted revenues or costs, development timelines, discount rates, and probability of regulatory success. The Company evaluates each performance obligation to determine if it can be satisfied at a point in time or over time, and it measures the services delivered to the licensee, which are periodically reviewed based on the progress of the related

Upfront Fees: If a license to the Company’s intellectual property is determined to be distinct from the other performance obligations identified in the arrangement, the Company recognizes revenues from the transaction price allocated to the license when the license is transferred to the licensee and the licensee is able to use and benefit from the license. For licenses that are bundled with other promises, the Company utilizes judgment to assess the nature of the combined performance obligation to determine whether the combined performance obligation is satisfied over time or at a point in time.

Milestone Payments: At the inception of each arrangement that includes milestone payments (variable consideration), the Company evaluates whether the milestones are considered probable of being reached and estimates the amount to be included in the transaction price using the most likely amount method. If it is probable that a significant revenue reversal would not occur, the associated milestone value is included in the transaction price. Milestone payments that are not within the Company’s or the licensee’s control, such as non-operational developmental and regulatory approvals, are generally not considered probable of being achieved until those approvals are received. At the end of each reporting period, the Company re-evaluates the probability of achievement of milestones that are within its or the licensee’s control, such as operational developmental milestones and any related constraint, and, if necessary, adjusts its estimate of the overall transaction price. Any such adjustments are recorded on a cumulative catch-up basis, which would affect collaboration revenues and earnings in the period of adjustment. Revisions to the Company’s estimate of the transaction price may also result in negative licensing revenues and earnings in the period of adjustment.

In an asset acquisition, payments incurred prior to regulatory approval to acquire rights to in-process research and development (“IPR&D”) projects are expensed as acquired IPR&D and milestones expense in the unaudited condensed consolidated statements of operations unless the project has an alternative future use. These costs include upfront and development milestone payments related to R&D collaborations, licensing arrangements, or other asset acquisitions that provide rights to develop, manufacture and/or sell pharmaceutical products. Where contingent development milestone payments are due to third parties, prior to regulatory approval, the payment obligations are expensed when the milestone results are achieved. Regulatory and commercial milestone payments made to third parties subsequent to regulatory approval are capitalized as intangible assets and amortized to intangible asset amortization over the remaining useful life of the related product.

The Company evaluates its financial instruments to determine if such instruments are derivatives or contain features that qualify as embedded derivatives. For derivative instruments that are bifurcated from a host contract, the Company recognizes them as either assets or liabilities in the unaudited condensed consolidated balance sheets and measures them at fair value. Embedded derivatives are remeasured at each reporting date, with changes in fair value recognized in earnings within loss on derivative liability in the unaudited condensed consolidated statements of operations. The Company initially assesses the probability of triggering events for bifurcated embedded derivatives in determining fair value. The probability is assessed at each reporting period.

The Company may scale-up and make commercial quantities of its product candidates prior to the date it anticipates that such product will receive final regulatory approval. The scale-up and commercial production of pre-launch inventory involves the risk that such products may not be approved for marketing on a timely basis, or ever. This risk notwithstanding, the Company may scale-up and build pre-launch inventory of products that have not received final regulatory approval when the Company believes such action is appropriate in relation to the commercial value of the product launch opportunity. We capitalize inventory costs associated with our products prior to regulatory approval when, based on management's judgment, future commercialization is considered probable and the future economic benefit is expected to be realized; otherwise, such costs are expensed as research and development. The determination to capitalize inventory costs is based on various factors, including status and expectations of the regulatory approval process, any known safety or efficacy concerns, potential labeling restrictions, and any other impediments to obtaining regulatory approval. The Company had no pre-approval inventory on its unaudited condensed consolidated balance sheets as of March 31, 2026, or December 31, 2025. Inventory used in clinical trials is also expensed as research and development expense when selected for such use. Inventory that can be used in the production of either clinical or commercial products is expensed as research and development costs when identified for use in a clinical manufacturing campaign. The cost of finished goods inventory that is shipped to a customer

The Company performs an assessment of the recoverability of capitalized inventory during each reporting period and writes down any excess and obsolete inventory to its net realizable value in the period in which the impairment is first identified. Such impairment charges, should they occur, are recorded as a component of cost of product revenue in the unaudited condensed consolidated statements of operations. The determination of whether inventory costs will be realizable requires the use of estimates by management. If actual market conditions are less favorable than projected by management, additional write downs of inventory may be required. Additionally, the Company’s products are subject to strict quality control and monitoring, which is performed throughout the manufacturing process. In the event that certain batches or units of product do not meet quality specifications, the Company will record a charge to cost of product revenue, to write down any unsaleable inventory to its estimated net realizable value. For the three months ended March 31, 2026, the Company recognized $0.5 million related to write-downs for unsaleable inventory. There was no write-down for unsaleable inventory for the three months ended March 31, 2025.

The components of cost of product revenue are royalties and expenses directly attributable to revenue. To date, the Company has generated revenue from product sales of MIPLYFFA and OLPRUVA, reimbursements received under the global EAP, royalties or net sales milestone payments generated under the AZSTARYS License Agreement, and consulting agreements.

Prior to our acquisition of the assets of Orphazyme A/S (“Orphazyme”) in May 2022, Orphazyme had entered into an asset purchase agreement with LadRx Corporation, which was assigned to XOMA (US) LLC, a wholly-owned subsidiary of XOMA Corporation (“XOMA”), in June 2023 (“XOMA License Agreement”). Under the XOMA License Agreement, XOMA is entitled to a mid-single digit percentage royalty with respect to net sales of MIPLYFFA as well as milestone payments based on future potential sales and regulatory milestones.

On August 30, 2023, Acer and Relief Therapeutics SA (“Relief”) entered into an exclusive license agreement (the “Relief License Agreement”). Pursuant to the Relief License Agreement, Zevra is obligated to pay royalties of 10% of U.S. net sales of OLPRUVA up to a maximum of $45.0 million, plus specified regulatory milestones, for total payments to Relief of up to $56.5 million. On April 10, 2025, Relief sold the rights to this royalty to Soleus Capital Management L.P.

Accounts and other receivables consist of receivables from MIPLYFFA and OLPRUVA product sales, receivables under the AZSTARYS License Agreement, receivables related to the Commave Settlement Agreement, the global EAP, and income tax receivables and other receivables due to the Company. Receivables under the AZSTARYS License Agreement are recorded for amounts due to the Company related to royalties on product sales. Receivables under the global EAP are recorded for revenue from arimoclomol in France and select territories outside of Europe. The Company provides reserves against receivables for estimated losses that may result from a customer's inability to pay. Receivables are evaluated to determine if any reserve or allowance should be recorded based on consideration of the current economic environment, expectations of future economic conditions, specific circumstances and the Company’s own historical collection experience. Amounts determined to be uncollectible are charged or written-off against the reserve.

Major components of research and development costs include cash compensation, stock-based compensation, depreciation and amortization expense on research and development property and equipment, costs of preclinical studies, clinical trials and related clinical manufacturing, costs of drug development, costs of materials and supplies, facilities cost, overhead costs, regulatory and compliance costs, and fees paid to consultants and other entities that conduct certain research and development activities on the Company’s behalf. Costs incurred in research and development are expensed as incurred.

The Company enters into contractual agreements with third-party vendors who provide research and development, manufacturing, and other services in the ordinary course of business. Some of these contracts are subject to milestone-based invoicing and services are completed over an extended period of time. The Company records liabilities under these contractual commitments when an obligation has been incurred. This accrual process involves reviewing open contracts and purchase orders, communicating with the applicable personnel to identify services that have been performed and estimating the level of service performed and the associated cost when the Company has not yet been invoiced or otherwise notified of actual cost. The majority of the service providers invoice the Company monthly in arrears for services performed. The Company makes estimates of the accrued expenses as of each balance sheet date based on the facts and circumstances known. The Company periodically confirms the accuracy of the estimates with the service providers and make adjustments, if necessary.

The Company recognizes deferred tax assets and liabilities for the expected future tax consequences of temporary differences between the financial reporting and tax basis of assets and liabilities, as well as for operating loss and tax credit carryforwards. Deferred tax assets and liabilities are measured using the tax rates that are expected to apply to taxable income for the years in which those tax assets and liabilities are expected to be realized or settled. Valuation allowances are recorded to reduce deferred tax assets to the amount the Company believes is more likely than not to be realized.

The Company is subject to taxation in the United States (including federal, state, and local jurisdictions) and the Kingdom of Denmark. Generally, the Company is subject to examination by tax jurisdictions from 2021 to 2024 tax years as the statute of limitation (excluding net operating loss carryforwards) are 3 to 4 years in the United States and Kingdom of Denmark. Tax liabilities may arise from interpretations and judgments made by the Company with regard to transfer pricing in the application of the relevant statutes, regulations, tax rulings and case law across the various jurisdictions. The Company uses significant judgment in (1) determining whether the technical merits of tax positions taken in the various jurisdictions are more-likely-than-not to be sustained based on applicable tax law and (2) measuring the related amount of tax liability that qualifies for recognition. The United States federal and state tax jurisdictions can audit the net operating loss carryforwards from the tax years in which the statute of limitation has expired but can only adjust the net operating loss carryforwards. No income tax returns are currently under examination by taxing authorities.

On December 22, 2017, the U.S. government enacted H.R. 1, “An Act to provide for reconciliation pursuant to titles II and V of the concurrent resolution on the budget for fiscal year 2018” (“Tax Act”). Effective January 1, 2018, the Tax Act provides for a new global intangible low-taxed income (“GILTI”) provision. Under the GILTI provision, certain foreign subsidiary earnings in excess of an allowable return on the foreign subsidiary’s tangible assets are included in U.S. taxable income. The Company has not recorded any deferred taxes for future GILTI inclusions as any future inclusions are expected to be treated as a period expense.

On July 4, 2025, the One Big Beautiful Bill Act (the “OBBB”), which includes a broad range of tax reform provisions, was signed into law in the United States. This includes a net Controlled Foreign Corporation (“CFC”) tested income (“NCTI”) provision, which is an update of the GILTI provision that was effective under H.R. 1. The Company has not recorded any deferred taxes for future NCTI inclusions as any future inclusions are expected to be treated as a period expense. The Company continues to assess the impact of the OBBB but currently does not expect the OBBB to have a material impact on the Company's estimated annual effective tax rate in 2026.

The Company measures and recognizes compensation expense for all stock-based payment awards made to employees, officers and directors based on the estimated fair values of the awards as of the grant date. The Company records the value of the portion of the award that is ultimately expected to vest as expense over the requisite service period. The Company also accounts for equity instruments issued to non-employees using a fair value approach under ASC subtopic 505-50. The Company values equity instruments and stock options granted using the Black-Scholes-Merton (“BSM”) option pricing model.

The Company uses the two-class method to compute net income (loss) per common share because the Company has issued securities, other than common stock, that contractually entitle the holders to participate in dividends and earnings of the Company. The two-class method requires earnings for the period to be allocated between common stock and participating securities based upon their respective rights to receive distributed and undistributed earnings. Holders of each series of the Company’s convertible preferred stock, if applicable, and select warrants are entitled to participate in distributions, when and if declared by the board of directors, that are made to common stockholders and, as a result, are considered participating securities.

Operating segments are defined as components of an enterprise (business activity from which it earns revenue and incurs expenses) for which discrete financial information is available and regularly reviewed by the chief operating decision maker (“CODM”) in deciding how to allocate resources and in assessing performance. The Company’s CODM is its Chief Executive Officer. The Company views its operations and manages its business as a single operating and reporting segment. See Note C for further information.

Assets and liabilities are translated into the reporting currency using the exchange rates in effect on the balance sheet dates. Equity accounts are translated at historical rates, except for the change in retained earnings during the year, which is the result of the income statement translation process. Revenue and expense accounts are translated using the weighted average exchange rate during the period. The cumulative translation adjustments associated with the net assets of foreign subsidiaries are recorded in accumulated other comprehensive income (loss) in the accompanying unaudited condensed consolidated statements of stockholders’ equity.

The Company accounts for warrants as either equity-classified or liability-classified instruments based on an assessment of the warrant’s specific terms and applicable authoritative guidance in FASB ASC Topic 480, Distinguishing Liabilities from Equity (“ASC 480”) and FASB ASC Topic 815, Derivatives and Hedging (“ASC 815”). The assessment considers whether the warrants are freestanding financial instruments pursuant to ASC 480, meet the definition of a liability pursuant to ASC 480, and whether the warrants meet all of the requirements for equity classification under ASC 815, including whether the warrants are indexed to the Company's own stock and whether the warrant holders could potentially require “net cash settlement” in a circumstance outside of the issuing company’s control, among other conditions for equity classification. This assessment, which requires the use of professional judgment, is conducted at the time of warrant issuance and as of each subsequent quarterly period end date while the warrants are outstanding.

For warrants that meet all criteria for equity classification, the warrants are required to be recorded as a component of additional paid-in capital on the unaudited condensed consolidated statements of changes in stockholders’ equity at the time of issuance. For warrants that do not meet all the criteria for equity classification, the warrants are required to be recorded at their initial fair value on the date of issuance, and on each balance sheet date thereafter. Changes in the estimated fair value of the warrants are recognized as a non-cash gain or loss in other expense, net, on the unaudited condensed consolidated statements of operations. The fair value of the warrants was estimated using the BSM option pricing model.

In December 2023, the FASB issued Accounting Standards Update (“ASU”) No. 2023-09, Income Taxes (“Topic 740”): Improvements to Income Tax Disclosures. ASU 2023-09 establishes new income tax disclosure requirements in addition to modifying and eliminating certain existing requirements. Under the new guidance, entities must consistently categorize and provide greater disaggregation of information in the reconciliation of the effective tax rate to the statutory tax rate and must also further disaggregate income taxes paid. The Company adopted ASU 2023-09 for the year ended December 31, 2025 using a retrospective approach and

In November 2024, the FASB issued ASU No. 2024-03, Income Statement: Reporting Comprehensive Income-Expense Disaggregation Disclosures (“Subtopic 220-40”): Disaggregation of Income Statement Expenses. The new standard requires disclosure of specified information about certain costs and expenses. ASU 2024-03 is effective for fiscal years beginning after December 15, 2026 and for interim periods within fiscal years beginning after December 15, 2027. Early adoption is permitted. The Company is currently evaluating this guidance to determine the impact it may have on its consolidated financial statements disclosures.