CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (Unaudited) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2012	Dec. 31, 2011
Net revenues	$ 197,402	$ 183,236	$ 558,047	$ 535,784
Cost of revenues	95,238	87,024	260,959	246,548
Gross profit	102,164	96,212	297,088	289,236
Operating expenses:
Research, development and engineering	20,248	16,829	59,525	51,386
Selling, general and administrative	45,442	41,976	134,476	128,510
Restructuring and other related charges	1,868	0	1,868	0
Total operating expenses	67,558	58,805	195,869	179,896
Operating income	34,606	37,407	101,219	109,340
Interest and other income, net	177	406	464	989
Income before income taxes	34,783	37,813	101,683	110,329
Income tax expense	6,577	6,915	23,990	25,179
Net income	$ 28,206	$ 30,898	$ 77,693	$ 85,150
Earnings per common share:
Basic	$ 0.68	$ 0.73	$ 1.87	$ 1.91
Diluted	$ 0.66	$ 0.71	$ 1.82	$ 1.86
Shares used in computing basic earnings per common share	41,745	42,541	41,629	44,623
Shares used in computing diluted earnings per common share	42,618	43,640	42,579	45,857
Cash dividends declared per common share	$ 0.10	$ 0.05	$ 0.30	$ 0.15