v3.8.0.1
Document and Entity Information - shares
3 Months Ended
Mar. 31, 2018
Apr. 30, 2018
Document Information [Line Items]    
Document Type 10-Q  
Amendment Flag false  
Document Period End Date Mar. 31, 2018  
Document Fiscal Year Focus 2018  
Document Fiscal Period Focus Q1  
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 Large Accelerated Filer  
American Depositary Shares    
Document Information [Line Items]    
Entity Common Stock, Shares Outstanding   293,218,435
Ordinary Shares    
Document Information [Line Items]    
Entity Common Stock, Shares Outstanding   365,705