Statement of Earnings (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Income Statement [Abstract]
Net revenues	$ 86,435	$ 85,901	$ 174,515	$ 157,087
Cost of goods sold	60,265	58,000	123,345	108,049
Gross profit	26,170	27,901	51,170	49,038
Operating expenses:
Research, development and engineering	6,948	7,453	14,198	15,140
Selling, general and administrative	10,713	10,583	21,477	20,626
Amortization of acquired intangible assets	1,419	3,425	3,126	3,671
Total operating expenses	19,080	21,461	38,801	39,437
Operating income	7,090	6,440	12,369	9,601
Other income (expense):
Interest income	49	36	96	76
Interest expense	(322)	(480)	(732)	(693)
Other income (expense), net	2,165	(1,252)	2,373	(1,335)
Income before income tax provision	8,982	4,744	14,106	7,649
Provision for income tax	(3,235)	(1,361)	(4,784)	(2,287)
Net income	$ 5,747	$ 3,383	$ 9,322	$ 5,362
Net income per share:
Basic	$ 0.18	$ 0.11	$ 0.30	$ 0.17
Diluted	$ 0.18	$ 0.11	$ 0.29	$ 0.17
Cash dividends per common share	$ 0.035	$ 0.03	$ 0.065	$ 0.06
Weighted average shares used in per share calculation:
Basic	31,499	31,127	31,439	31,037
Diluted	32,235	31,849	32,142	31,737