Condensed Consolidated Statements of Operations (Unaudited) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013	Dec. 31, 2012
Income Statement [Abstract]
Net revenues	$ 54,844	$ 51,698	$ 164,379	$ 139,316
Cost of revenues	21,644	22,958	65,383	61,874
Gross profit	33,200	28,740	98,996	77,442
Operating expenses:
Research and development	29,870	82,711	120,926	151,865
Selling, general and administrative	10,930	12,675	29,602	38,676
Gain on sale of TPack	0	0	(19,699)	0
Amortization	62	338	254	1,589
Restructuring charges, net	38	6,218	1,130	6,218
Total operating expenses	40,900	101,942	132,213	198,348
Operating loss	(7,700)	(73,202)	(33,217)	(120,906)
Interest income (expense), net	525	892	4,679	3,316
Other income (expense), net	92	1,366	309	1,539
Loss before income taxes	(7,083)	(70,944)	(28,229)	(116,051)
Income tax expense	201	618	581	458
Net loss	$ (7,284)	$ (71,562)	$ (28,810)	$ (116,509)
Basic and diluted net loss per share (in dollars per share)	$ (0.10)	$ (1.08)	$ (0.40)	$ (1.81)
Shares used in calculating basic and diluted net loss per share (in shares)	73,989	66,113	71,986	64,489