Consolidated Condensed Statements Of Operations (USD $) In Thousands, except Per Share data	3 Months Ended		6 Months Ended
	Sep. 24, 2011	Sep. 25, 2010	Sep. 24, 2011	Sep. 25, 2010
Consolidated Condensed Statements Of Operations [Abstract]
Net sales	$ 101,602	$ 100,598	$ 193,844	$ 182,513
Cost of sales	47,247	43,818	91,780	78,998
Gross margin	54,355	56,780	102,064	103,515
Operating expenses:
Research and development	19,682	15,450	38,449	30,542
Selling, general and administrative	16,760	15,372	31,366	29,383
Restructuring and other costs, net		401		401
Impairment of non-marketable securities		500		500
Provision for litigation expenses and settlements				135
Patent agreement, net		(4,000)		(4,000)
Total operating expenses	36,442	27,723	69,815	56,961
Income from operations	17,913	29,057	32,249	46,554
Interest income, net	112	233	266	461
Other income (expense), net	(27)	(14)	(44)	18
Income before income taxes	17,998	29,276	32,471	47,033
Provision (benefit) for income taxes	6,751	(1,598)	12,046	(1,443)
Net income	$ 11,247	$ 30,874	$ 20,425	$ 48,476
Basic income per share:	$ 0.17	$ 0.45	$ 0.31	$ 0.72
Diluted income per share:	$ 0.17	$ 0.42	$ 0.30	$ 0.67
Basic weighted average common shares outstanding:	64,426	68,513	65,763	67,576
Diluted weighted average common shares outstanding:	67,265	72,878	68,657	71,971