Summary of Significant Accounting Policies (Tables)

3 Months Ended

Aug. 31, 2015

Accounting Policies [Abstract]

Schedule of Inventory, Current [Table Text Block]

	August 31, 2015		May 31, 2015
Raw materials	$	1,026,000	$	958,000
Work in progress		834,000		831,000
Finished products		249,000		238,000
Total	$	2,109,000	$	2,027,000

Schedule of Share-based Compensation, Stock Options, Activity [Table Text Block]

		Exercise Price Weighted Average
	Option Shares
Outstanding  May 31, 2015	1,148,000	$	0.60
Exercised	(17,773)		0.42
Forfeited	(20,375)		0.69
Outstanding August 31, 2015	1,109,852	$	0.60

Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]

	Three Months  Ended  August 31,
	2015		2014
Numerator:
Loss from continuing operations	$	(72,335)	$	(219,268)
Denominator for basic net loss per common share		7,582,056		7,547,839
Effect of dilutive securities:
Options		--		--
Denominator for diluted net loss per common share		7,582,056		7,547,839
Basic net loss per common share	$	(0.01)	$	(0.03)
Diluted net loss per common share	$	(0.01)	$	(0.03)