Income Taxes - Deferred Tax Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Deferred tax assets:
Net operating loss carryforwards	$ 230,775	$ 115,370
Tax credits	20,973	17,853
Stock based compensation	28,268	23,768
Other	26,889	31,227
Total deferred tax assets	306,905	188,218
Valuation allowance	(162,892)	(67,890)
Total deferred tax assets net of valuation allowance	144,013	120,328
Deferred tax liabilities:
Fixed assets	(4,997)	(5,011)
Intangible assets	(81,877)	(89,106)
Convertible debt	(57,430)	(26,506)
Indefinite lived intangible assets	(89,701)	(89,701)
Total deferred tax liabilities	(234,005)	(210,324)
Net deferred tax liabilities	$ (89,992)	$ (89,996)