SHAREHOLDERS` EQUITY (Tables)

12 Months Ended

May 31, 2018

Stockholders' Equity Note [Abstract]

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

	NUMBER OF STOCK OPTIONS	PRICE RANGE PER SHARE	WEIGHTED AVERAGE EXERCISE PRICE
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
Options granted	287,000	$ 2.41-$3.90	$	3.63
Options exercised	(34,750)	$ 0.71-$ 1.04	$	0.80
Options canceled or expired	(10,625)	$ 0.71-$ 2.41	$	1.44
Options outstanding at May 31, 2018	1,138,625	$ 0.71-$ 3.90	$	1.65

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, 2017	517,250	$	0.96
Granted	287,000	$	3.63
Vested/Exercised	(212,125)	$	1.00
Forfeited	(9,125)	$	1.56
Nonvested shares at May 31, 2018	583,000	$	2.34

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, 2018
	NUMBER  OUTSTANDING 05/31/2018				WEIGHTED  AVERAGE EXERCISE PRICE
RANGE OF EXERCISE PRICES
$ 0.71-$ 0.84	460,625	4.66	$0.80	371,750	$0.79
$ 0.85-$ 1.04	65,000	2.22	$0.99	32,625	$0.98
$ 1.20-$ 1.61	330,000	8.32	$1.26	151,250	$1.23
$ 2.41-$ 3.90	283,000	8.69	$3.65	--	--