Statement of Earnings (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Jun. 30, 2012	Jun. 30, 2011
Income Statement [Abstract]
Net revenues	$ 80,857	$ 101,778
Cost of goods sold	53,668	66,743
Gross profit	27,189	35,035
Operating expenses:
Research, development and engineering	6,649	6,933
Selling, general and administrative	11,187	11,129
Amortization of acquisition-related intangible assets	640	642
Total operating expenses	18,476	18,704
Operating income	8,713	16,331
Other income (expense):
Interest income	84	69
Interest expense	(257)	(284)
Other income (expense), net	701	(394)
Income before income tax provision	9,241	15,722
Provision for income tax	(3,234)	(5,746)
Net income	$ 6,007	$ 9,976
Net income per share:
Basic	$ 0.19	$ 0.32
Diluted	$ 0.19	$ 0.30
Weighted average shares used in per share calculation:
Basic	31,351	31,508
Diluted	32,378	32,806