SHAREHOLDERS' EQUITY (Details) - Non-vested Stock Options Activity	12 Months Ended
	May 31, 2020 $ / shares shares
Non-vested Stock Options Activity [Abstract]
Non-vested shares, number of shares | shares	769,584
Non-vested shares, weighted average grant date fair value | $ / shares	$ 2.49
Granted, number of shares | shares	517,500
Granted, weighted average grant date fair value | $ / shares	$ 4.47
Vested, number of shares | shares	(407,750)
Vested, weighted average grant date fair value | $ / shares	$ 2.25
Forfeited, number of shares | shares	(56,750)
Forfeited, weighted average grant date fair value | $ / shares	$ 3.55
Non-vested shares, number of shares | shares	822,584
Non-vested shares, weighted average grant date fair value | $ / shares	$ 3.78