CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (USD $) In Thousands, except 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 sales	$ 17,671	$ 15,464	$ 35,590	$ 35,032
Cost of sales	10,686	10,051	23,039	22,814
Gross profit	6,985	5,413	12,551	12,218
Selling, general, and administrative expenses	3,707	3,808	7,668	6,541
Engineering expense	2,221	1,910	4,046	3,729
Operating income (loss)	1,057	(305)	837	1,948
Interest expense	8	15	16	33
Other expense – net	33	30	62	51
Income (loss) before incomes taxes	1,016	(350)	759	1,864
Income tax provision (benefit)	376	(133)	281	708
Net income (loss)	$ 640	$ (217)	$ 478	$ 1,156
Earnings (loss) per common share:
Basic net income (loss) per share	$ 0.07	$ (0.02)	$ 0.05	$ 0.12
Diluted net income (loss) per share	$ 0.06	$ (0.02)	$ 0.05	$ 0.12
Weighted-average basic shares outstanding	9,766,000	9,644,000	9,741,000	9,608,000
Weighted-average diluted shares outstanding	9,962,000	9,644,000	9,937,000	9,705,000