SHAREHOLDERS' EQUITY (Tables)

12 Months Ended

May 31, 2017

Stockholders' Equity Note [Abstract]

Share-based Compensation, Activity [Table Text Block]

	NUMBER OF STOCK OPTIONS	PRICE RANGE PER SHARE	WEIGHTED AVERAGE EXERCISE PRICE
Options outstanding at May 31, 2015	1,148,000	$ 0.38-$ 0.85	$0.60
Options granted	345,000	$ 1.04-$ 1.20	$1.17
Options exercised	(269,625)	$ 0.38-$ 0.84	$0.41
Options canceled or expired	(24,375)	$ 0.43-$ 1.04	$0.74
Options outstanding at May 31, 2016	1,199,000	$ 0.43-$ 1.20	$0.81
Options granted	55,000	$ 1.52-$ 1.61	$1.55
Options exercised	(341,500)	$ 0.43-$ 1.04	$0.46
Options canceled or expired	(15,500)	$ 0.43-$ 1.04	$0.90
Options outstanding at May 31, 2017	897,000	$ 0.71-$ 1.61	$0.98

Schedule of Nonvested Share Activity [Table Text Block]

		STOCK OPTIONS WEIGHTED AVERAGE AVERAGE GRANT DATE FAIR VALUE
	NUMBER OF SHARES
Nonvested shares at May 31, 2016	673,250	$	0.99
Granted	55,000	$	1.55
Vested/Issued	(196,750)	$	0.96
Forfeited	(14,250)	$	0.92
Nonvested shares at May 31, 2017	517,250	$	0.96

Schedule of Share-based Compensation, Shares Authorized under Stock Option Plans, by Exercise Price Range [Table Text Block]

		WEIGHTED  AVERAGE  REMAINING  CONTRACTUAL LIFE IN YEARS
			WEIGHTED  AVERAGE EXERCISE  PRICE	NUMBER  EXERCISABLE AT MAY 31, 2017
	NUMBER  OUTSTANDING 05/31/2017				WEIGHTED  AVERAGE EXERCISE PRICE
RANGE OF EXERCISE PRICES
$ 0.71-$ 0.84	488,500	5.43	$0.79	287,000	$0.76
$ 0.85-$ 1.04	78,500	1.90	$0.99	24,000	$0.96
$ 1.20-$ 1.61	330,000	8.86	$1.26	68,750	$1.20