Income Taxes - Significant Components of Deferred Tax Assets and Liabilities (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Deferred tax assets:
Net operating loss carryforwards	$ 423,776	$ 391,385
Research and other credits	66,666	61,707
Deferred revenue	29,758us-gaap_DeferredTaxAssetsDeferredIncome	35,588us-gaap_DeferredTaxAssetsDeferredIncome
Stock-based compensation	21,948	25,962
Sale of future royalties	20,153	28,057
Capitalized research expenses	14,795	17,687
Reserves and accruals	8,288	14,685
Property, plant and equipment	8,264	8,580
Other	2,218us-gaap_DeferredTaxAssetsOther	2,539us-gaap_DeferredTaxAssetsOther
Deferred tax assets before valuation allowance	595,866us-gaap_DeferredTaxAssetsGross	586,190us-gaap_DeferredTaxAssetsGross
Valuation allowance for deferred tax assets	(595,690)	(586,040)
Total deferred tax assets	176us-gaap_DeferredTaxAssetsNet	150us-gaap_DeferredTaxAssetsNet
Total deferred tax liabilities	0us-gaap_DeferredTaxLiabilities	0us-gaap_DeferredTaxLiabilities
Net deferred tax assets	$ 176us-gaap_DeferredTaxAssetsLiabilitiesNet	$ 150us-gaap_DeferredTaxAssetsLiabilitiesNet

Deferred tax assets, capitalized research expenses.

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Deferred tax assets depreciation property and equipment.

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Deferred Tax Assets From Sale Of Future Royalties

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Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences from deferred income.

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Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences and carryforwards.

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-Glossary Deferred Tax Asset

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Amount after allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences and carryforwards, net of deferred tax liability attributable to taxable temporary differences.

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Amount after allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences and carryforwards.

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Amount before allocation of valuation allowances of deferred tax asset attributable to deductible operating loss carryforwards.

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Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences not separately disclosed.

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Amount before allocation of valuation allowances of deferred tax asset attributable to deductible research tax credit carryforwards.

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Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences from share-based compensation.

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Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences from reserves and accruals.

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Amount of deferred tax assets for which it is more likely than not that a tax benefit will not be realized.

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Amount of deferred tax liability attributable to taxable temporary differences net of deferred tax asset attributable to deductible temporary differences and carryforwards after valuation allowances.

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