Annual report pursuant to Section 13 and 15(d)

Document and Entity Information

v2.4.0.8
Document and Entity Information (USD $)
In Millions, except Share data, unless otherwise specified
12 Months Ended
Dec. 31, 2013
Dec. 12, 2014
Jun. 30, 2013
Document and Entity Information [Abstract]      
Entity Registrant Name LIGAND PHARMACEUTICALS INC    
Entity Central Index Key 0000886163    
Document Type 10-K/A    
Document Period End Date Dec. 31, 2013    
Amendment Flag true    
Amendment Description Correcting certain coding errors in certain dates included in XBRL    
Document Fiscal Year Focus 2013    
Document Fiscal Period Focus FY    
Current Fiscal Year End Date --12-31    
Entity Filer Category Accelerated Filer    
Entity Common Stock, Shares Outstanding   19,645,775  
Entity Public Float     $ 676.8
Entity Voluntary Filers No    
Entity Well-known Seasoned Issuer Yes    
Entity Current Reporting Status Yes