Summary of Significant Accounting Policies	9 Months Ended
Summary of Significant Accounting Policies	Sep. 30, 2021
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. We are registered as an Irish public limited company. Our headquarters are in Dublin, Ireland and we have operations in St. Louis, Missouri, United States. Our lead product candidate, FT218, is an investigational once-nightly, extended-release formulation of sodium oxybate for the treatment of excessive daytime sleepiness (“EDS”) and cataplexy in adults with narcolepsy. We are primarily focused on the development and potential United States (“U.S.”) Food and Drug Administration (“FDA”) approval of FT218. In December 2020, we submitted a New Drug Application (“NDA”) to the FDA for FT218 to treat excessive daytime sleepiness and cataplexy in adults with narcolepsy. In February 2021, the NDA for FT218 was accepted by the FDA and was assigned a Prescription Drug User Fee Act (“PDUFA”) target action date of October 15, 2021. On October 15, 2021, we announced that the FDA informed us that the review of our NDA for FT218 was ongoing beyond its previously assigned target action date. Outside of our lead product candidate, we continue to evaluate opportunities to expand our product portfolio. As of September 30, 2021, we do not have any approved or commercialized products in our portfolio. Basis of Presentation. The unaudited condensed consolidated balance sheet as of September 30, 2021, which is derived from the prior year 2020 audited consolidated financial statements, and the interim unaudited condensed consolidated financial statements presented herein, have been prepared in accordance with accounting principles generally accepted in the U.S. (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 2020 Annual Report on Form 10-K filed with the SEC on March 9, 2021. 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. Reclassifications Certain reclassifications are made to prior year amounts whenever necessary to conform with the current year presentation. Certain adjustments have been made to the balances within Note 11: Other Assets and Liabilities for the year ended December 31, 2020 to condense line items of the same nature into a single line. Revenue. Prior to June 30, 2020, revenue was earned from the sales of pharmaceutical products. Product Sales Prior to June 30, 2020, we sold products primarily through wholesalers and considered these wholesalers to be our customers. Under ASC 606, revenue from product sales is recognized when the customer obtains control of our product, which occurs typically upon receipt by the customer. Our gross product sales were subject to a variety of price adjustments in arriving at reported net product sales. These adjustments included estimates of product returns, chargebacks, payment discounts, rebates, and other sales allowances and were estimated based on analysis of historical data for the product or comparable products, future expectations for such products and other judgments and analysis. For a complete discussion of the accounting for net product revenue, see Note 4: Revenue Recognition.