CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2016
Income Statement [Abstract]
Net revenue	$ 1,792,892	$ 1,779,748	$ 1,413,698
Cost of goods sold	898,311	1,022,959	813,873
Gross profit	894,581	756,789	599,825
Selling and marketing	256,092	285,453	198,309
General and administrative	247,828	211,409	192,452
Research and development	196,373	137,915	119,807
Business reorganization	14,742	0	71,285
Depreciation and amortization	43,969	30,707	28,800
Total operating expenses	759,004	665,484	610,653
Income (loss) from operations	135,577	91,305	(10,828)
Interest and other, net	1,048	(15,690)	(30,205)
Gain on long-term investments, net	0	1,350	2,683
Income (loss) before income taxes	136,625	76,965	(38,350)
(Benefit from) provision for income taxes	(36,908)	9,662	(30,048)
Net income (loss)	$ 173,533	$ 67,303	$ (8,302)
Earnings (loss) per share:
Basic earnings (loss) per share (in dollars per share)	$ 1.57	$ 0.73	$ (0.10)
Diluted earnings (loss) per share (in dollars per share)	$ 1.54	$ 0.72	$ (0.10)