| Document and Entity Information | Nov. 14, 2019 |
| Cover [Abstract] | |
| Entity Tax Identification Number | 00-0000000 |
| Amendment Flag | false |
| Entity Central Index Key | 0000897448 |
| Document Type | 8-K |
| Document Period End Date | Nov. 14, 2019 |
| Entity Registrant Name | AMARIN CORP PLC\UK |
| Entity Incorporation, State or Country Code | X0 |
| Entity File Number | 0-21392 |
| Entity Address, Address Line One | 77 Sir John Rogerson’s Quay |
| Entity Address, Address Line Two | Block C |
| Entity Address, Address Line Three | Grand Canal Docklands |
| Entity Address, City or Town | Dublin |
| Entity Address, Postal Zip Code | 2 |
| Entity Address, Country | IE |
| City Area Code | +353 1 |
| Local Phone Number | 6699 020 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | American Depositary Shares (ADS(s)), each ADS representing the right to receive one (1) Ordinary Share of Amarin Corporation plc |
| Trading Symbol | AMRN |
| Security Exchange Name | NASDAQ |
| Entity Emerging Growth Company | false |
