Quarterly report pursuant to Section 13 or 15(d)

Financing Arrangements (Narrative) (Details)

v2.4.1.9
Financing Arrangements (Narrative) (Details) (USD $)
1 Months Ended
Aug. 31, 2014
Mar. 31, 2015
Dec. 31, 2014
Jul. 31, 2014
Aug. 12, 2014
Debt Instrument [Line Items]          
Additional final payment on borrowings (percent)       6.00%lgnd_LineOfCreditFacilityAdditionalPaymentOnBorrowingsPercentage  
Initial debt value   $ 198,219,000us-gaap_ConvertibleDebtNoncurrent $ 195,908,000us-gaap_ConvertibleDebtNoncurrent    
Long-term debt issuance costs   3,177,000us-gaap_UnamortizedDebtIssuanceExpense 3,388,000us-gaap_UnamortizedDebtIssuanceExpense    
Common stock, shares available to be issued 3,264,643us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights        
Exercise price of convertible bond hedge $ 75.05lgnd_ExercisePriceofConvertibleBondHedge        
Exercise price $ 125.08us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1        
Proceeds from issuance of warrants 11,600,000us-gaap_AdjustmentsToAdditionalPaidInCapitalWarrantIssued        
Current notes payable   348,000us-gaap_NotesPayableCurrent 334,000us-gaap_NotesPayableCurrent    
Common Stock          
Debt Instrument [Line Items]          
Share price         $ 55.59us-gaap_SharePrice
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_CommonStockMember
2019 convertible senior notes          
Debt Instrument [Line Items]          
Aggregate principal amount outstanding   245,000,000us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= lgnd_A2019ConvertibleSeniorNotesMember
245,000,000us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= lgnd_A2019ConvertibleSeniorNotesMember
   
Initial debt value   198,219,000us-gaap_ConvertibleDebtNoncurrent
/ us-gaap_DebtInstrumentAxis
= lgnd_A2019ConvertibleSeniorNotesMember
195,908,000us-gaap_ConvertibleDebtNoncurrent
/ us-gaap_DebtInstrumentAxis
= lgnd_A2019ConvertibleSeniorNotesMember
   
Convertible notes payable, Viking Therapeutics, Inc.          
Debt Instrument [Line Items]          
Interest rate   2.00%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= us-gaap_ConvertibleNotesPayableMember
     
Term of notes 2 years        
Current notes payable   348,000us-gaap_NotesPayableCurrent
/ us-gaap_DebtInstrumentAxis
= us-gaap_ConvertibleNotesPayableMember
334,000us-gaap_NotesPayableCurrent
/ us-gaap_DebtInstrumentAxis
= us-gaap_ConvertibleNotesPayableMember
   
Senior Notes          
Debt Instrument [Line Items]          
Payment for convertible bond hedges 48,100,000lgnd_PaymentsforConvertibleBondHedges
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SeniorNotesMember
       
Senior Notes | 2019 convertible senior notes          
Debt Instrument [Line Items]          
Interest rate 0.75%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= lgnd_A2019ConvertibleSeniorNotesMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SeniorNotesMember
       
Aggregate principal amount outstanding 245,000,000us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= lgnd_A2019ConvertibleSeniorNotesMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SeniorNotesMember
       
Net proceeds from note after debt issuance costs 239,300,000us-gaap_ProceedsFromDebtNetOfIssuanceCosts
/ us-gaap_DebtInstrumentAxis
= lgnd_A2019ConvertibleSeniorNotesMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SeniorNotesMember
       
Initial conversion rate 0.0133251us-gaap_DebtInstrumentConvertibleConversionRatio1
/ us-gaap_DebtInstrumentAxis
= lgnd_A2019ConvertibleSeniorNotesMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SeniorNotesMember
       
Initial conversion price $ 75.05us-gaap_DebtInstrumentConvertibleConversionPrice1
/ us-gaap_DebtInstrumentAxis
= lgnd_A2019ConvertibleSeniorNotesMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SeniorNotesMember
       
Premium percentage 35.00%lgnd_DebtInstrumentPremiumPercentageofConversionPrice
/ us-gaap_DebtInstrumentAxis
= lgnd_A2019ConvertibleSeniorNotesMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SeniorNotesMember
       
Proceeds from issuance of debt 245,000,000us-gaap_ProceedsFromIssuanceOfDebt
/ us-gaap_DebtInstrumentAxis
= lgnd_A2019ConvertibleSeniorNotesMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SeniorNotesMember
       
Debt discount rate 5.83%us-gaap_FairValueInputsDiscountRate
/ us-gaap_DebtInstrumentAxis
= lgnd_A2019ConvertibleSeniorNotesMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SeniorNotesMember
       
Initial debt value 192,500,000us-gaap_ConvertibleDebtNoncurrent
/ us-gaap_DebtInstrumentAxis
= lgnd_A2019ConvertibleSeniorNotesMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SeniorNotesMember
       
Debt issuance costs 5,700,000us-gaap_DebtIssuanceCosts
/ us-gaap_DebtInstrumentAxis
= lgnd_A2019ConvertibleSeniorNotesMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SeniorNotesMember
       
Equity component of convertible debt recorded as a reduction to additional paid-in capital 1,200,000us-gaap_AdjustmentsToAdditionalPaidInCapitalEquityComponentOfConvertibleDebt
/ us-gaap_DebtInstrumentAxis
= lgnd_A2019ConvertibleSeniorNotesMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SeniorNotesMember
       
Long-term debt issuance costs 4,500,000us-gaap_UnamortizedDebtIssuanceExpense
/ us-gaap_DebtInstrumentAxis
= lgnd_A2019ConvertibleSeniorNotesMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SeniorNotesMember
       
Term of notes 5 years        
Carrying value of the equity component of debt, net of issuance costs   $ 51,300,000us-gaap_DebtInstrumentConvertibleCarryingAmountOfTheEquityComponent
/ us-gaap_DebtInstrumentAxis
= lgnd_A2019ConvertibleSeniorNotesMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SeniorNotesMember
$ 51,300,000us-gaap_DebtInstrumentConvertibleCarryingAmountOfTheEquityComponent
/ us-gaap_DebtInstrumentAxis
= lgnd_A2019ConvertibleSeniorNotesMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SeniorNotesMember
   
Senior Notes | 2019 convertible senior notes | Debt Instrument, Redemption, Period One          
Debt Instrument [Line Items]          
Threshold trading days 20us-gaap_DebtInstrumentConvertibleThresholdTradingDays
/ us-gaap_DebtInstrumentAxis
= lgnd_A2019ConvertibleSeniorNotesMember
/ us-gaap_DebtInstrumentRedemptionPeriodAxis
= us-gaap_DebtInstrumentRedemptionPeriodOneMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SeniorNotesMember
       
Consecutive trading days 30 days        
Percentage of stock price trigger 130.00%us-gaap_DebtInstrumentConvertibleThresholdPercentageOfStockPriceTrigger
/ us-gaap_DebtInstrumentAxis
= lgnd_A2019ConvertibleSeniorNotesMember
/ us-gaap_DebtInstrumentRedemptionPeriodAxis
= us-gaap_DebtInstrumentRedemptionPeriodOneMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SeniorNotesMember
       
Senior Notes | 2019 convertible senior notes | Debt Instrument, Redemption, Period Two          
Debt Instrument [Line Items]          
Threshold trading days 5us-gaap_DebtInstrumentConvertibleThresholdTradingDays
/ us-gaap_DebtInstrumentAxis
= lgnd_A2019ConvertibleSeniorNotesMember
/ us-gaap_DebtInstrumentRedemptionPeriodAxis
= us-gaap_DebtInstrumentRedemptionPeriodTwoMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SeniorNotesMember
       
Consecutive trading days 10 days        
Maximum threshold percentage of debt trading price trigger 98.00%lgnd_DebtInstrumentConvertibleMaximumThresholdPercentageofDebtTradingPriceTrigger
/ us-gaap_DebtInstrumentAxis
= lgnd_A2019ConvertibleSeniorNotesMember
/ us-gaap_DebtInstrumentRedemptionPeriodAxis
= us-gaap_DebtInstrumentRedemptionPeriodTwoMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SeniorNotesMember