Condensed Consolidated Statements of Operations (Unaudited) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2011	Dec. 31, 2010
Condensed Consolidated Statements of Operations [Abstract]
Net sales	$ 19,599	$ 19,614	$ 55,727	$ 51,260
Cost of sales	11,644	12,339	32,429	31,676
Gross profit	7,955	7,275	23,298	19,584
Selling, general, and administrative expenses	3,883	3,972	11,638	10,563
Engineering expense	2,127	1,462	6,475	4,317
Relocation expense				211
Operating income	1,945	1,841	5,185	4,493
Interest expense	80	167	316	550
Other expense - net	39	31	89	176
Income before incomes taxes	1,826	1,643	4,780	3,767
Income tax provision	767	690	2,008	1,582
Net income	$ 1,059	$ 953	$ 2,772	$ 2,185
Earnings per common share:
Basic net income per share	$ 0.11	$ 0.10	$ 0.29	$ 0.23
Diluted net income per share	$ 0.11	$ 0.10	$ 0.29	$ 0.23
Weighted-average basic shares outstanding	9,489,000	9,429,000	9,468,000	9,409,000
Weighted-average diluted shares outstanding	9,598,000	9,464,000	9,597,000	9,430,000