Income Taxes (Details 1) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Deferred assets:
Net operating loss carryforwards	$ 193,747	$ 196,421
Research and AMT credit carryforwards	28,288	30,092
Fixed assets and intangibles	13,237	17,293
Accrued expenses	1,579	1,474
Contingent liabilities	579	582
Deferred revenue	771us-gaap_DeferredTaxAssetsDeferredIncome	760us-gaap_DeferredTaxAssetsDeferredIncome
Present value of royalties	11,686	12,175
Organon termination asset	(111)lgnd_DeferredTaxAssetsTerminationAsset	(4,073)lgnd_DeferredTaxAssetsTerminationAsset
Organon termination liability	111	4,073
Royalty obligation	0lgnd_DeferredTaxAssetsRoyaltyObligation	0lgnd_DeferredTaxAssetsRoyaltyObligation
Deferred rent	730	1,634
Lease termination costs	0	0
Capital loss carryforwards	0	148
Other	5,780us-gaap_DeferredTaxAssetsOther	3,701us-gaap_DeferredTaxAssetsOther
Deferred tax assets	256,397us-gaap_DeferredTaxAssetsGross	264,280us-gaap_DeferredTaxAssetsGross
Valuation allowance for deferred tax assets	(240,420)	(249,470)
Net deferred tax assets	15,977us-gaap_DeferredTaxAssetsNet	14,810us-gaap_DeferredTaxAssetsNet
Deferred tax liabilities:
Retrophin fair value adjustment	(1,396)	(859)
Convertible debt	(1,436)	0
Identified intangibles	(13,146)	(13,984)
Identified indefinite lived intangibles	(3,048)	(2,639)
Total	$ (3,049)us-gaap_DeferredTaxLiabilities	$ (2,672)us-gaap_DeferredTaxLiabilities

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