Consolidated Statements of Operations (Unaudited) (USD $)	3 Months Ended		6 Months Ended
	Oct. 31, 2013	Oct. 31, 2012	Oct. 31, 2013	Oct. 31, 2012
Income Statement [Abstract]
Revenues	$ 7,410,229	$ 6,959,023	$ 14,776,959	$ 14,957,508
Costs and expenses:
Cost of sales	5,841,266	5,771,958	11,646,310	12,076,405
Engineering	299,692	189,728	619,019	395,836
Selling, general and administrative	1,630,267	2,189,278	3,670,000	4,543,495
Gain on asset disposal	103,000		103,000
Total costs and expenses	7,668,225	8,150,964	15,832,329	17,015,736
Loss from operations	(257,996)	(1,191,941)	(1,055,370)	(2,058,228)
Other income (expense):
Interest expense, net	(91,578)	(71,368)	(175,995)	(142,750)
Currency gain (loss)	11,382	15,552	11,543	(22,496)
Total other expense, net	(80,196)	(55,816)	(164,452)	(165,246)
Loss before income tax expense	(338,192)	(1,247,757)	(1,219,822)	(2,223,474)
Income tax expense
Net loss	$ (338,192)	$ (1,247,757)	$ (1,219,822)	$ (2,223,474)
Net loss per share of common stock
Basic	$ (0.18)	$ (0.70)	$ (0.67)	$ (1.25)
Diluted	$ (0.18)	$ (0.70)	$ (0.67)	$ (1.25)