Statements of Consolidated Operations (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Mar. 31, 2012	Mar. 31, 2011	Mar. 31, 2010
Statements of Consolidated Operations [Abstract]
Net sales	$ 84,942	$ 78,200	$ 69,027
Cost of sales	49,728	47,248	48,376
Gross profit	35,214	30,952	20,651
Selling, general and administrative expenses	15,661	14,361	20,554
Engineering expense	12,531	6,923	6,003
Relocation expense		211	817
Operating income (loss)	7,022	9,457	(6,723)
Interest expense	396	694	891
Other expense - net	109	213	458
Income (loss) before income taxes	6,517	8,550	(8,072)
Income tax provision (benefit)	2,741	3,524	(2,029)
Net income (loss)	$ 3,776	$ 5,026	$ (6,043)
Earnings (loss) per common share:
Basic net income (loss) per share:	$ 0.40	$ 0.53	$ (0.64)
Diluted net income (loss) per share:	$ 0.39	$ 0.53	$ (0.64)
Weighted-average basic shares outstanding	9,473,000	9,414,000	9,388,000
Weighted-average diluted shares outstanding	9,593,000	9,443,000	9,388,000