Share-based Compensation - Additional Information (Details1) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2026	Sep. 30, 2025	Sep. 30, 2026	Sep. 30, 2025
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share-based compensation expense	$ 26,747,000	$ 24,664,000	$ 94,216,000	$ 72,441,000
Avadel Pharmaceuticals Plc
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share-based compensation expense	0		18,400,000
Location, Statement of Income, Balance [Axis]: us-gaap:CostOfGoodsAndServicesSold
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share-based compensation expense	1,834,000	1,621,000	5,519,000	4,882,000
Location, Statement of Income, Balance [Axis]: us-gaap:ResearchAndDevelopmentExpense
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share-based compensation expense	6,953,000	6,435,000	23,640,000	18,836,000
Location, Statement of Income, Balance [Axis]: us-gaap:ResearchAndDevelopmentExpense \| Avadel Pharmaceuticals Plc
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share-based compensation expense			6,700,000
Location, Statement of Income, Balance [Axis]: us-gaap:ResearchAndDevelopmentExpense \| Avadel Pharmaceuticals Plc \| Maximum
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share-based compensation expense	100,000
Location, Statement of Income, Balance [Axis]: us-gaap:SellingGeneralAndAdministrativeExpense
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share-based compensation expense	17,960,000	$ 16,608,000	65,057,000	$ 48,723,000
Location, Statement of Income, Balance [Axis]: us-gaap:SellingGeneralAndAdministrativeExpense \| Avadel Pharmaceuticals Plc \| Former Alkermes CEO
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share-based compensation expense	$ 500,000		$ 18,900,000