Income Taxes - Schedule of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Deferred tax assets:
Reserves and accrued expenses	$ 121,509	$ 186,120
Inventories	5,094	8,967
Net operating loss carryforwards	71,774	87,010
R&D credits	9,570	7,933
Foreign tax credits	0	9,203
Valuation allowance	(25,690)	(26,009)
Total deferred tax assets	182,257	273,224
Deferred tax liabilities:
Reserves and accrued expenses	39,566	13,915
Amortizable intangible assets	935,874	1,400,792
Plant and equipment	5,748	6,102
Total deferred tax liabilities	$ 981,188	$ 1,420,809