Condensed Consolidated Statements of Operations (Unaudited) - USD ($)	3 Months Ended
	Jul. 31, 2016	Jul. 31, 2015
Income Statement [Abstract]
Revenues	$ 4,914,857	$ 7,337,682
Costs and expenses:
Cost of sales	4,189,240	5,934,477
Engineering	56,026	53,958
Selling, general and administrative	1,555,950	1,404,266
Total costs and expenses	5,801,216	7,392,701
Loss from operations	(886,359)	(55,019)
Other income (expense):
Interest expense	(38,793)	(62,644)
Other gain (loss)	(1,790)	408
Total other expense, net	(40,583)	(62,236)
Net loss	(926,942)	(117,255)
Dividend - Series A preferred stock		62,660
Net loss allocated to common shareholders	$ (926,942)	$ (179,915)
Net loss per share of common stock basic and diluted	$ (0.43)	$ (0.19)
Weighted average common shares outstanding basic and diluted	2,175,363	933,761