Statement of Earnings (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
Income Statement [Abstract]
Net revenues	$ 63,812	$ 80,041	$ 213,130	$ 280,823
Cost of goods sold	44,753	56,889	146,364	191,158
Gross profit	19,059	23,152	66,766	89,665
Operating expenses:
Research, development and engineering	6,532	6,368	19,933	19,805
Selling, general and administrative	9,490	10,827	30,582	32,142
Amortization of acquisition-related intangible assets	559	640	1,683	1,885
Total operating expenses	16,581	17,835	52,198	53,832
Operating income	2,478	5,317	14,568	35,833
Other income (expense):
Interest income	113	85	281	246
Interest expense	(228)	(282)	(719)	(859)
Other income (expense), net	(392)	862	515	2,129
Income before income tax provision	1,971	5,982	14,645	37,349
Provision for income tax	(782)	(311)	(5,092)	(10,755)
Net income	$ 1,189	$ 5,671	$ 9,553	$ 26,594
Net income per share:
Basic	$ 0.04	$ 0.18	$ 0.31	$ 0.85
Diluted	$ 0.04	$ 0.18	$ 0.30	$ 0.82
Cash dividends per common share	$ 0.03	$ 0	$ 0.03	$ 0
Weighted average shares used in per share calculation:
Basic	31,005	31,203	31,222	31,335
Diluted	31,487	32,238	31,917	32,505