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
Net revenues	$ 181,365	$ 175,600
Cost of revenues	83,669	81,542
Gross profit	97,696	94,058
Operating expenses:
Research, development and engineering	19,696	16,906
Selling, general and administrative	45,904	42,116
Total operating expenses	65,600	59,022
Operating income	32,096	35,036
Interest and other income, net	12	641
Income before income taxes	32,108	35,677
Income tax expense	8,545	8,946
Net income	$ 23,563	$ 26,731
Earnings per common share:
Basic	$ 0.57	$ 0.57
Diluted	$ 0.55	$ 0.56
Shares used in computing basic earnings per common share	41,660	46,688
Shares used in computing diluted earnings per common share	42,570	48,060
Cash dividends declared per common share	$ 0.10	$ 0.05