Income Taxes - Reconciliation (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Reconciliation between the amount of reported income tax and the amount computed using U.S. Statutory rate
Pre-tax loss	$ (151,949)	$ (117,313)	$ (128,530)
Loss at Statutory Rates	(31,909)	(39,887)	(43,700)
Difference in Foreign Tax Rates		326	150
Research and Development Credits	(2,056)	(2,847)	(5,203)
State Taxes	(6,406)	(6,283)	(7,268)
Income Tax Rate Change		99,528
Other	(1,175)	(321)	2,111
Milestone Abandonment	(6,220)
Intangible Impairment	19,105
Recognition of APIC NOLs		(5,729)
Impact of Pass-through Entities	(913)	(2,775)
Change in Valuation Allowance	28,809	(66,294)	$ 53,910
Income Tax (Benefit) Provision	$ (765)	$ (24,282)

Amount represents income tax reconciliation impact of pass through entities.

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Amount represents income tax reconciliation of additional paid in capital and net operating losses.

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Amount represents income tax reconciliation of Milestone Abandonment.

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Amount of income (loss) from continuing operations, including income (loss) from equity method investments, before deduction of income tax expense (benefit), and income (loss) attributable to noncontrolling interest.

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Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

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Amount of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to increase (decrease) in the valuation allowance for deferred tax assets.

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