Significant Accounting Policies (Tables)

6 Months Ended

Nov. 30, 2016

Accounting Policies [Abstract]

Schedule of Inventory, Current [Table Text Block]

	November 30, 2016		May 31, 2016
Raw materials	$	821,000	$	942,000
Work in progress		735,000		690,000
Finished products		325,000		231,000
Total	$	1,881,000	$	1,863,000

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

		Exercise Price Weighted Average
	Option Shares
Outstanding May 31, 2016	1,199,000	$	0.81
Exercised	(130,875)		0.43
Cancelled or expired	(5,000)		0.96
Granted	55,000		1.55
Outstanding November 30, 2016	1,118,125	$	0.89

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

	Six Months Ended November 30,				Three Months Ended November 30,
	2016		2015		2016		2015
Numerator:
Loss from continuing operations	$	(258,600)	$	(139,103)	$	(202,887)	$	(66,768)
Denominator for basic loss  Per common share		8,208,672		7,584,333		8,189,066		7,586,635
Effect of dilutive securities:
Options		--		--		--		--
Denominator for diluted loss  per common share		8,208,672		7,584,333		8,189,066		7,586,635
Basic net loss per common share	$	(0.03)	$	(0.02)	$	(0.02)	$	(0.01)
Diluted net loss per common share	$	(0.03)	$	(0.02)	$	(0.02)	$	(0.01)