Statement of Earnings (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Income Statement [Abstract]
Net revenues	$ 85,901	$ 68,461	$ 157,087	$ 149,318
Cost of goods sold	58,000	48,057	108,049	101,841
Gross profit	27,901	20,404	49,038	47,477
Operating expenses:
Research, development and engineering	7,453	7,035	15,140	13,965
Selling, general and administrative	10,583	9,508	20,626	20,298
Amortization of acquisition-related intangible assets	3,425	484	3,671	1,124
Total operating expenses	21,461	17,027	39,437	35,387
Operating income	6,440	3,377	9,601	12,090
Other income (expense):
Interest income	36	84	76	168
Interest expense	(480)	(234)	(693)	(491)
Other income (expense), net	(1,252)	206	(1,335)	907
Income before income tax provision	4,744	3,433	7,649	12,674
Provision for income tax	(1,361)	(1,076)	(2,287)	(4,310)
Net income	$ 3,383	$ 2,357	$ 5,362	$ 8,364
Net income per share:
Basic	$ 0.11	$ 0.08	$ 0.17	$ 0.27
Diluted	$ 0.11	$ 0.07	$ 0.17	$ 0.26
Cash dividends per common share	$ 0.03	$ 0	$ 0.06	$ 0
Weighted average shares used in per share calculation:
Basic	31,127	31,310	31,037	31,331
Diluted	31,849	31,975	31,737	32,192