Document and Entity Information - USD ($)
12 Months Ended
Dec. 31, 2018
Feb. 25, 2019
Jun. 30, 2018
Document And Entity Information      
Entity Registrant Name Retrophin, Inc.    
Entity Central Index Key 0001438533    
Trading Symbol rtrx    
Entity Voluntary Filers No    
Entity Current Reporting Status Yes    
Current Fiscal Year End Date --12-31    
Entity Filer Category Large Accelerated Filer    
Entity Well-known Seasoned Issuer Yes    
Entity Common Stock, Shares Outstanding   41,412,835  
Entity Public Float     $ 912,685,763
Document Type 10-K    
Document Period End Date Dec. 31, 2018    
Amendment Flag false    
Document Fiscal Year Focus 2018    
Document Fiscal Period Focus FY    
Entity Emerging Growth Company false    
Entity Shell Company false    
Entity Small Business false