Condensed Consolidated Statements of Operations (Unaudited) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Jun. 30, 2012	Jun. 30, 2011
Condensed Consolidated Statements of Operations [Abstract]
Net revenues	$ 41,294	$ 60,844
Cost of revenues	18,355	26,331
Gross profit	22,939	34,513
Operating expenses:
Research and development	34,771	28,368
Selling, general and administrative	12,470	12,556
Amortization of purchased intangible assets	650	1,099
Restructuring charges, net		913
Total operating expenses	47,891	42,936
Operating loss	(24,952)	(8,423)
Interest income (expense), net	1,679	1,281
Other income (expense), net	83	75
Loss before income taxes	(23,190)	(7,067)
Income tax expense (benefit)	200	(190)
Net loss	$ (23,390)	$ (6,877)
Basic and diluted net loss per share	$ (0.37)	$ (0.11)
Shares used in calculating basic and diluted net loss per share	62,409	63,878