Statement of Earnings (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
Income Statement Abstract
Net revenues	$ 99,004	$ 89,910	$ 200,782	$ 174,785
Cost of goods sold	67,526	58,102	134,269	113,484
Gross profit	31,478	31,808	66,513	61,301
Operating expenses:
Research, development and engineering	6,504	6,597	13,437	13,609
Selling, general and administrative	10,186	10,454	21,315	20,876
Amortization of acquisition-related intangible assets	603	1,923	1,245	3,846
Restructuring charges	0	4	0	51
Total operating expenses	17,293	18,978	35,997	38,382
Operating income	14,185	12,830	30,516	22,919
Other income (expense):
Interest income	92	78	161	152
Interest expense	(293)	(395)	(577)	(815)
Other income (expense), net	1,661	(1,961)	1,267	818
Income before income tax provision	15,645	10,552	31,367	23,074
Provision for income tax	(4,698)	(3,671)	(10,444)	(9,667)
Net income	$ 10,947	$ 6,881	$ 20,923	$ 13,407
Net income per share
Basic	$ 0.35	$ 0.22	$ 0.67	$ 0.43
Diluted	$ 0.34	$ 0.22	$ 0.64	$ 0.42
Weighted average shares used in per share calculation
Basic (shares)	31,383	31,149	31,445	31,269
Diluted (shares)	32,545	31,623	32,669	31,755