STOCK-BASED COMPENSATION (Details 3) - Outstanding Options Stock Option Transactions [Member] $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Aug. 31, 2021 USD ($) $ / shares shares
Options outstanding, beginning (in thousands) | shares	2,766
Options granted (in thousands) | shares	206
Options cancelled and adjusted (in thousands) | shares	(6)
Options exercised (in thousands) | shares	(641)
Options outstanding, ending (in thousands) | shares	2,325
Options fully vested and expected to vest (in thousands) | shares	2,290
Weighted average exercise price outstanding, beginning | $ / shares	$ 2.16
Weighted average exercise price Options granted | $ / shares	2.93
Weighted average exercise price Options cancelled | $ / shares	1.95
Weighted average exercise price Options exercised | $ / shares	2.46
Weighted average exercise price outstanding, ending | $ / shares	2.14
Weighted average exercise price fully vested and expected to vest | $ / shares	$ 2.14
Aggregate intrinsic value, beginning | $	$ 807
Aggregate intrinsic value, ending | $	12,365
Aggregate intrinsic value for options fully vested and expected to vest | $	$ 12,177