CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2014
Income Statement [Abstract]
Product revenue	$ 286,217	$ 355,579	$ 348,318
Service revenue	148,548	155,674	147,199
Royalty revenue	41,193	41,842	57,648
Total revenue	475,958	553,095	553,165
Product cost of revenue	206,859	237,679	237,076
Service cost of revenue	64,347	70,730	75,930
Restructuring charges related to cost of revenue	0	0	539
Total cost of revenue	271,206	308,409	313,545
Gross margin	204,752	244,686	239,620
Operating expenses:
Research and development	48,703	58,618	64,375
Sales and marketing	108,735	113,954	118,771
General and administrative	53,793	56,513	57,865
Restructuring charges	4,006	1,666	10,675
Goodwill impairment	55,613	0	0
Total operating expenses	270,850	230,751	251,686
Gain on sale of assets	0	462	267
Income (loss) from operations	(66,098)	14,397	(11,799)
Other income and expense	(191)	13,836	1,296
Interest expense	(6,817)	(9,460)	(9,754)
Loss on debt extinguishment	(394)	(1,295)	0
Income (loss) before income taxes	(73,500)	17,478	(20,257)
Income tax provision	1,183	718	1,217
Net income (loss)	$ (74,683)	$ 16,760	$ (21,474)
Basic net income (loss) per share	$ (0.28)	$ 0.07	$ (0.09)
Diluted net income (loss) per share	$ (0.28)	$ 0.06	$ (0.09)
Weighted average shares:
Basic	262,730	254,665	247,024
Diluted	262,730	260,027	247,024