CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (USD $) In Thousands, except Per Share data	3 Months Ended		6 Months Ended
	Oct. 01, 2011	Oct. 02, 2010	Oct. 01, 2011	Oct. 02, 2010
Net sales	$ 81,884	$ 59,554	$ 158,930	$ 118,025
Cost of sales	45,943	33,553	89,229	70,551
Gross profit	35,941	26,001	69,701	47,474
Operating expenses:
Selling, service and administration	14,884	15,046	31,380	27,891
Research, development and engineering	10,742	10,217	21,976	20,428
Legal settlement costs			550
Net operating expenses	25,626	25,263	53,906	48,319
Operating income (loss)	10,315	738	15,795	(845)
Non-operating (expense) income:
Gain on sale of previously impaired auction rate securities			2,729
Interest and other (expense) income, net	(406)	187	(543)	245
Total non-operating (expense) income	(406)	187	2,186	245
Income (loss) before income taxes	9,909	925	17,981	(600)
Provision for (benefit from) income taxes	1,372	1,536	3,531	(190)
Net income (loss)	$ 8,537	$ (611)	$ 14,450	$ (410)
Net income (loss) per share - basic	$ 0.30	$ (0.02)	$ 0.51	$ (0.01)
Net income (loss) per share - diluted	$ 0.29	$ (0.02)	$ 0.49	$ (0.01)
Weighted average number of shares - basic	28,747	28,010	28,609	27,901
Weighted average number of shares - diluted	29,426	28,010	29,326	27,901