Summary of Significant Accounting Policies	3 Months Ended
Summary of Significant Accounting Policies	Mar. 31, 2023
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies Nature of Operations. Avadel Pharmaceuticals plc (Nasdaq: AVDL) (“Avadel,” the “Company,” “we,” “our,” or “us”) is a biopharmaceutical company. The Company is registered as an Irish public limited company. The Company’s headquarters are in Dublin, Ireland with operations in Dublin, Ireland and St. Louis, Missouri, United States (“U.S.”). The Company’s lead product, LUMRYZ, formally known as FT218, is an extended-release formulation of sodium oxybate indicated to be taken once at bedtime for the treatment of cataplexy or excessive daytime sleepiness (“EDS”) in adults with narcolepsy. On May 1, 2023, LUMRYZ was approved by the U.S. Food and Drug Administration (“FDA”). In approving LUMRYZ, the FDA approved a risk evaluation and mitigation strategy (“REMS”) for LUMRYZ to help ensure that the benefits of the drug in the treatment of cataplexy and EDS in narcolepsy outweigh the risks of serious adverse outcomes resulting from inappropriate prescribing, misuse, abuse, and diversion of the drug. Under this REMS, healthcare providers must be specially certified, pharmacies, practitioners, or health care settings that dispense the drug must be specially certified and the drug must be dispensed to patients with documentation of safe use conditions. The FDA also granted Orphan Drug Exclusivity (“ODE”) to LUMRYZ for a period of seven years until May 1, 2030. Outside of LUMRYZ, the Company continues to evaluate opportunities to expand its product portfolio. As of the date of this Quarterly Report, the Company does not have any other commercialized products in its portfolio. Liquidity and Going Concern. The accompanying unaudited condensed consolidated financial statements are prepared in accordance with accounting principles generally accepted in the U.S. (“U.S. GAAP”) applicable to a going concern, which contemplates the realization of assets and the satisfaction of liabilities in the normal course of business. The Company has a recent history of generating losses and negative cash flows from operations, an accumulated shareholders’ deficit as of the date of these unaudited condensed consolidated financial statements and approximately $83,391 of cash and cash equivalents and $17,532 of marketable securities available for use to fund its operations, debt service and capital requirements. The Company’s ability to generate revenue is expected to start following the commercial launch of LUMRYZ in the U.S., which is dependent, in part, on the Company’s ability to successfully complete its commercialization efforts and on market acceptance of LUMRYZ in the U.S. On March 29, 2023, the Company and Avadel CNS Pharmaceuticals, LLC, an indirect wholly-owned subsidiary of the Company (“Avadel CNS”) entered into a royalty purchase agreement with RTW Investments, L.P. that could provide the Company up to $75,000 of royalty financing in two tranches. The first tranche of $30,000 is available subject to the Company’s first shipment of LUMRYZ. The second tranche is available to use, at the Company’s election, upon achieving quarterly net revenue of $25,000. The second tranche will expire on August 31, 2024, if the quarterly net revenue target is not reached and if it is not used by the Company by that time. At March 31, 2023, the Company had outstanding $117,375 aggregate principal amount of its 4.50% exchangeable senior notes due October 2023 (the “October 2023 Notes”). Over the course of April 3 and April 4, 2023, Avadel Finance Cayman Limited, a Cayman Islands exempted company and an indirect wholly-owned subsidiary of the Company (the “Issuer”), completed an exchange of $96,188 of its $117,375 October 2023 Notes for $106,268 of a new series 6.0% exchangeable notes due April 2027 (the “April 2027 Notes”) (the “2023 Exchange Transaction”). The remaining $21,187 aggregate principal amount of the October 2023 Notes will maintain a maturity date of October 2, 2023. On April 3, 2023, the Company completed the sale of ordinary shares, nominal value $0.01 per share (“Ordinary Shares”) in the form of American Depositary Shares (“ADSs”) and Series B Non-Voting Convertible Preferred Shares (“Series B Preferred Shares”) in an underwritten public offering. The Company received net proceeds from the equity financing of $135,125, of which $40,000 was received on March 31, 2023 and $95,125 was received on April 3, 2023. The $40,000 of net proceeds received prior to the completed public offering was included in the unaudited condensed consolidated balance sheet as proceeds received in advance of Series B Preferred Shares issuance at March 31, 2023. As a result of the 2023 Exchange Transaction and the public offering, the Company has concluded that cash on hand provides sufficient capital to meet the Company’s operating, debt service and capital requirements for the next twelve months following the date of this Quarterly Report. At-the-Market Offering Program On February 5, 2020, the Company entered into an Open Market Sale AgreementSM (the “Sales Agreement”) with Jefferies LLC (“Jefferies”) with respect to an at-the-market offering program (“ATM Program”) under which the Company may offer and sell its ADSs (such ADSs sold under the ATM Program, “ATM ADSs”) through Jefferies as its sales agent. The Company agreed to pay Jefferies a commission up to 3.0% of the aggregate gross sales proceeds of such ATM ADSs. The initial aggregate offering price of the ATM Program was up to $50,000 of ADSs pursuant to its prospectus, dated February 14, 2020, included with the Company’s Registration Statement on Form S-3 (File No. 333-236258) (the “2020 Prospectus”). In August 2022, the Company filed an additional prospectus, dated September 12, 2022, included with the Company’s new Registration Statement on Form S-3 (File No. 333-267198) (the “2022 Prospectus”), in order to allocate up to $100,000 in additional ADSs to the ATM Program. The 2020 Shelf Registration expired on February 14, 2023. Pursuant to the Sales Agreement, the Company had issued and sold 1,564 ADSs during the quarter ended March 31, 2023, resulting in net proceeds to the Company of approximately $11,913. The Company may offer and sell up to an additional $96,064 of ADSs under the ATM Program that remain available for sale pursuant to the 2022 Prospectus. Basis of Presentation. The unaudited condensed consolidated balance sheet as of March 31, 2023, which is derived from the prior year 2022 audited consolidated financial statements, and the interim unaudited condensed consolidated financial statements presented herein, have been prepared in accordance with U.S. GAAP, the requirements of Form 10-Q and Article 10 of Regulation S-X and, consequently, do not include all information or footnotes required by U.S. GAAP for complete financial statements or all the disclosures normally made in an Annual Report on Form 10-K. Accordingly, the unaudited condensed consolidated financial statements included herein should be read in conjunction with the audited consolidated financial statements and footnotes included in the Company’s 2022 Annual Report on Form 10-K filed with the United States Securities and Exchange Commission (“SEC”) on March 29, 2023. The unaudited condensed consolidated financial statements include the accounts of the Company and subsidiaries and reflect all adjustments (consisting only of normal recurring adjustments) that are, in the opinion of management, necessary for a fair presentation of the Company’s financial position, results of operations and cash flows for the dates and periods presented. All intercompany accounts and transactions have been eliminated. Results for interim periods are not necessarily indicative of the results to be expected during the remainder of the current year or for any future period.