Income Taxes - Tax Effects of Temporary Differences in Deferred Tax Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
NOL carryforwards	$ 203,928	$ 132,841
Research and development credits	28,535	23,118
Liability related to sale of future royalties	49,228	49,217
Deferred revenue	18,286	0
Disallowed interest expense	13,474	0
Other	5,807	3,088
Total	319,258	208,264
Valuation allowance	(317,828)	(206,397)
Net deferred assets	1,430	1,867
Property and equipment	(1,430)	(1,867)
Net deferred assets and liabilities	$ 0	$ 0

Deferred Tax Asset, Disallowed Interest Expense

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Deferred Tax Assets, Deferred Revenue

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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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Amount, after allocation of valuation allowances and deferred tax liability, of deferred tax asset attributable to deductible differences and carryforwards, without jurisdictional netting.

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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 allowance, of deferred tax asset attributable to deductible temporary differences, classified as other.

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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 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 from property, plant, and equipment.

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