Condensed Consolidated Statements of Cash Flows (USD $)	9 Months Ended
	Feb. 29, 2012 Unaudited	Feb. 28, 2011 Unaudited
Operating activities:
Net income	$ 1,336,071	$ 693,713
Adjustments to reconcile net income to net cash flows from operating activities:
Depreciation and amortization	383,677	351,205
Stock options issued for services	26,502	30,463
Deferred income taxes		(8,000)
Changes in other assets and liabilities:
Accounts receivable	(1,310,962)	3,040,534
Inventory	(2,639,345)	(346,493)
Costs and estimated earnings in excess of billings	(1,300,691)	(2,044,058)
Other current assets	159,594	73,883
Accounts payables	1,278,865	373,795
Accrued commissions	258,537	(9,271)
Billings in excess of costs and estimated earnings	636,400	(167,298)
Other current liabilities	387,084	(390,299)
Net operating activities	(784,268)	1,598,174
Investing activities:
Acquisition of property and equipment	(940,391)	(268,034)
Other investing activities	(4,231)	(4,268)
Net investing activities	(944,622)	(272,302)
Financing activities:
Principal repayments on long-term debt	(4,114)	(4,113)
Proceeds from issuance of common stock, net	230,666	9,650
Acquisition of treasury stock	(49,767)	(30,418)
Net financing activities	176,785	(24,881)
Net change in cash and cash equivalents	(1,552,105)	1,300,991
Cash and cash equivalents - beginning	2,193,534	197,587
Cash and cash equivalents - ending	$ 641,429	$ 1,498,578