Inventory - Schedule of Inventory (Parenthetical) (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Inventory Disclosure [Abstract]
Inventory deemed not saleable	$ 8,000	$ 5,100
Cost of goods sold inventory restructuring	$ 36,474	$ 39,228	$ 18,078

Cost of goods and services sold restructuring inventory.

No definition available.

Name:	amrn_CostOfGoodsAndServicesSoldRestructuringInventory
Namespace Prefix:	amrn_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration