v3.7.0.1
Document and Entity Information - shares
3 Months Ended
Mar. 31, 2017
May 05, 2017
Document And Entity Information [Abstract]    
Document Type 10-Q  
Amendment Flag false  
Document Period End Date Mar. 31, 2017  
Document Fiscal Year Focus 2017  
Document Fiscal Period Focus Q1  
Trading Symbol OREX  
Entity Registrant Name Orexigen Therapeutics, Inc.  
Entity Central Index Key 0001382911  
Current Fiscal Year End Date --12-31  
Entity Filer Category Smaller Reporting Company  
Entity Common Stock, Shares Outstanding   15,227,802