Condensed Consolidated Statements of Operations (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2015	Dec. 31, 2014
Income Statement [Abstract]
Net revenues	$ 40,623	$ 36,747	$ 118,179	$ 127,964
Cost of revenues	18,241	14,842	52,805	52,815
Gross profit	22,382	21,905	65,374	75,149
Operating expenses:
Research and development	22,377	24,721	66,405	82,636
Selling, general and administrative	8,232	8,707	25,369	25,684
Amortization of purchased intangible assets	0	0	0	105
Restructuring	(29)	221	82	1,322
Total operating expenses	30,580	33,649	91,856	109,747
Operating loss	(8,198)	(11,744)	(26,482)	(34,598)
Realized gain on short-term investments and interest income, net	148	485	2,024	1,214
Other income (expense), net	21	(10)	54	(2,536)
Loss before income taxes	(8,029)	(11,269)	(24,404)	(35,920)
Income tax provision (benefit)	170	862	(740)	993
Net loss	$ (8,199)	$ (12,131)	$ (23,664)	$ (36,913)	[1]
Basic and diluted net loss per share (in dollars per share)	$ (0.10)	$ (0.15)	$ (0.29)	$ (0.47)
Shares used in calculating basic and diluted net loss per share (in shares)	83,191	78,920	82,186	78,442

[1] The Statement of Cash Flows for the nine months ended December 31, 2014 reflects immaterial revisions to correct $0.3 million of outstanding payables related to purchases of property and equipment previously included in net cash used for investing activities to net cash used for operating activities and $0.1 million of net realized gains on short-term investments previously classified as net cash used for operating activities to net cash provided by investing activities. As a result, net cash used for operating activities increased by $0.4 million and net cash used for investing activities decreased by the corresponding amount.