v3.8.0.1
Document and Entity Information - shares
9 Months Ended
Sep. 30, 2017
Oct. 31, 2017
Document Information [Line Items]    
Document Type 10-Q  
Amendment Flag false  
Document Period End Date Sep. 30, 2017  
Document Fiscal Year Focus 2017  
Document Fiscal Period Focus Q3  
Trading Symbol AMRN  
Entity Registrant Name AMARIN CORP PLC\UK  
Entity Central Index Key 0000897448  
Current Fiscal Year End Date --12-31  
Entity Filer Category Accelerated Filer  
American Depositary Shares    
Document Information [Line Items]    
Entity Common Stock, Shares Outstanding   270,509,836
Ordinary Shares    
Document Information [Line Items]    
Entity Common Stock, Shares Outstanding   369,628