Condensed Consolidated Statements of Income (Unaudited) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Sep. 30, 2012	Oct. 02, 2011	Sep. 30, 2012	Oct. 02, 2011
Condensed Consolidated Statements of Income [Abstract]
Net revenues	$ 117,867	$ 136,275	$ 248,238	$ 280,756
Cost of revenues	38,980	43,345	82,293	88,213
Gross profit	78,887	92,930	165,945	192,543
Operating expenses:
Engineering and development	38,024	35,065	77,482	69,917
Sales and marketing	19,739	18,509	38,625	38,230
General and administrative	8,139	8,854	16,812	18,017
Total operating expenses	65,902	62,428	132,919	126,164
Operating income	12,985	30,502	33,026	66,379
Interest and other income, net	954	1,080	2,032	2,128
Income from continuing operations before income taxes	13,939	31,582	35,058	68,507
Income taxes	2,159	5,075	4,837	7,804
Income from continuing operations	11,780	26,507	30,221	60,703
Income from discontinued operations, net of income taxes	94	2,147	39	377
Net income	$ 11,874	$ 28,654	$ 30,260	$ 61,080
Income from continuing operations per share:
Basic	$ 0.13	$ 0.26	$ 0.32	$ 0.58
Diluted	$ 0.13	$ 0.26	$ 0.31	$ 0.58
Income from discontinued operations per share:
Basic		$ 0.02		$ 0.01
Diluted		$ 0.02
Net income per share:
Basic	$ 0.13	$ 0.28	$ 0.32	$ 0.59
Diluted	$ 0.13	$ 0.28	$ 0.31	$ 0.58
Number of shares used in per share calculations:
Basic	93,762	103,273	95,584	103,976
Diluted	93,949	103,562	96,159	104,676