Quarterly report pursuant to Section 13 or 15(d)

Lease Obligations (Narrative) (Details)

v2.4.1.9
Lease Obligations (Narrative) (Details) (USD $)
3 Months Ended 12 Months Ended
Mar. 31, 2015
Mar. 31, 2014
Dec. 31, 2013
Dec. 31, 2014
Operating Leased Assets [Line Items]        
Lease expiration year, minimum 2015      
Lease expiration year, maximum 2019      
Percentage of increase in annual base rent, minimum 3.00%lgnd_OperatingLeasesOfLesseeContingentRentalsBasisSpreadOnVariableRateMinimum      
Percentage of increase in annual base rent, maximum 3.50%lgnd_OperatingLeasesOfLesseeContingentRentalsBasisSpreadOnVariableRateMaximum      
Lease exit costs $ 223,000us-gaap_BusinessExitCosts1 $ 204,000us-gaap_BusinessExitCosts1    
Rent expense, net sublease income 900,000us-gaap_OperatingLeasesRentExpenseNet 900,000us-gaap_OperatingLeasesRentExpenseNet    
Adjustment for accretion and changes in lease assumptions 200,000lgnd_OperatingLeaseAdjustmentForAccretionAndChangesInLeaseAssumptions 200,000lgnd_OperatingLeaseAdjustmentForAccretionAndChangesInLeaseAssumptions    
Rent expense 200,000us-gaap_LeaseAndRentalExpense 200,000us-gaap_LeaseAndRentalExpense    
Deferred rent 318,000us-gaap_DeferredRentCreditNoncurrent     327,000us-gaap_DeferredRentCreditNoncurrent
Contract Termination        
Operating Leased Assets [Line Items]        
Lease exit costs $ 2,600,000us-gaap_BusinessExitCosts1
/ us-gaap_RestructuringCostAndReserveAxis
= us-gaap_ContractTerminationMember
  $ 3,300,000us-gaap_BusinessExitCosts1
/ us-gaap_RestructuringCostAndReserveAxis
= us-gaap_ContractTerminationMember