SHAREHOLDERS' EQUITY (Details) - Non-vested Stock Options Activity	12 Months Ended
	May 31, 2021 $ / shares shares
Non-vested Stock Options Activity [Abstract]
Non-vested shares, number of shares | shares	822,584
Non-vested shares, weighted average grant date fair value | $ / shares	$ 3.78
Granted, number of shares | shares	430,616
Granted, weighted average grant date fair value | $ / shares	$ 6.73
Vested, number of shares | shares	(409,459)
Vested, weighted average grant date fair value | $ / shares	$ 3.36
Forfeited, number of shares | shares	(50,500)
Forfeited, weighted average grant date fair value | $ / shares	$ 4.80
Non-vested shares, number of shares | shares	793,241
Non-vested shares, weighted average grant date fair value | $ / shares	$ 5.54