CONSOLIDATED STATEMENTS OF OPERATIONS (USD $) In Thousands, except Per Share data	3 Months Ended		6 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Net revenues	$ 176,948	$ 158,255	$ 352,548	$ 328,940
Cost of revenues	77,982	72,296	159,524	153,533
Gross profit	98,966	85,959	193,024	175,407
Operating expenses:
Research, development and engineering	17,651	15,206	34,557	30,107
Selling, general and administrative	44,418	36,742	86,534	75,428
Total operating expenses	62,069	51,948	121,091	105,535
Operating income	36,897	34,011	71,933	69,872
Interest and other income (expense), net	(58)	1,017	583	635
Income before income taxes	36,839	35,028	72,516	70,507
Income tax expense	9,318	9,599	18,264	19,132
Net income	$ 27,521	$ 25,429	$ 54,252	$ 51,375
Earnings per common share:
Basic	$ 0.62	$ 0.54	$ 1.19	$ 1.08
Diluted	$ 0.6	$ 0.52	$ 1.16	$ 1.05
Shares used in computing basic earnings per common share	44,556	47,087	45,664	47,607
Shares used in computing diluted earnings per common share	45,717	48,524	46,950	49,148
Cash dividends declared per common share	$ 0.05	$ 0.05	$ 0.10	$ 0.10