CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (UNAUDITED) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Income Statement [Abstract]
Net sales	$ 23,897	$ 17,671	$ 43,692	$ 35,590
Cost of sales	14,250	10,686	25,019	23,039
Gross profit	9,647	6,985	18,673	12,551
Selling, general, and administrative expenses	3,311	3,707	6,627	7,668
Engineering expense	1,915	2,221	3,742	4,046
Operating income	4,421	1,057	8,304	837
Interest expense	8	8	16	16
Other expense – net	26	33	94	62
Income before incomes taxes	4,387	1,016	8,194	759
Income tax provision	1,464	376	2,885	281
Net income	$ 2,923	$ 640	$ 5,309	$ 478
Earnings per common share:
Basic net income per share	$ 0.30	$ 0.07	$ 0.54	$ 0.05
Diluted net income per share	$ 0.29	$ 0.06	$ 0.53	$ 0.05
Weighted-average basic shares outstanding	9,876,000	9,766,000	9,859,000	9,741,000
Weighted-average diluted shares outstanding	10,177,000	9,962,000	10,094,000	9,937,000