Income Taxes - Schedule of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Deferred tax assets:
Net operating loss and other carryforwards	$ 53,632	$ 97,391
Tax credits	31,699	35,489
Deferred revenue	5,597	11,672
Stock based compensation	24,531	34,700
Contingent consideration	26,041	26,543
Employee compensation	3,212	6,116
Legal reserve		2,707
Rebate and returns reserve	8,215	7,582
Capitalized R&D	11,295	10,025
Other	12,368	4,096
Total deferred tax assets	176,590	236,321
Valuation allowance	(98,609)	(63,225)
Total deferred tax assets net of valuation allowance	77,981	173,096
Deferred tax liabilities:
Intangible assets	(91,991)	(245,500)
Convertible debt	(8,449)	(16,003)
Total deferred tax liabilities	(100,440)	(261,503)
Net deferred tax liability	$ (22,459)	$ (88,407)