Quarterly report pursuant to Section 13 or 15(d)

Document and Entity Information

v3.5.0.2
Document and Entity Information - shares
9 Months Ended
Sep. 30, 2016
Nov. 01, 2016
Document and Entity Information [Abstract]    
Entity Registrant Name LIGAND PHARMACEUTICALS INC  
Entity Central Index Key 0000886163  
Document Type 10-Q  
Document Period End Date Sep. 30, 2016  
Amendment Flag false  
Document Fiscal Year Focus 2016  
Document Fiscal Period Focus Q3  
Current Fiscal Year End Date --12-31  
Entity Filer Category Accelerated Filer  
Entity Common Stock, Shares Outstanding   20,900,189