STOCKHOLDERS EQUITY AND STOCK-BASED COMPENSATION (Details 4) - Outstanding Options Stock Option Transactions - USD ($)	12 Months Ended
	May 31, 2022	May 31, 2021	May 31, 2020
Options outstanding, beginning (in thousands)	2,766	3,153	3,107
Options granted (in thousands)	303	297	738
Options terminated (in thousands)	(105)	(455)	(457)
Options exercised (in thousands)	(1,367)	(229)	(235)
Options outstanding, ending (in thousands)	1,597	2,766	3,153
Options fully vested and expected to vest (in thousands)	1,570
Weighted average exercise price outstanding, beginning	$ 2.16	$ 2.17	$ 2.20
Weighted average exercise price granted	5.37	1.78	1.61
Weighted average exercise price terminated	1.59	2.31	1.98
Weighted average exercise price exercised	2.28	1.54	1.22
Weighted average exercise price outstanding, ending	2.70	$ 2.16	$ 2.17
Weighted average exercise price fully vested and expected to vest	$ 2.69
Aggregate intrinsic value, beginning	$ 807,000	$ 102,000	$ 283,000
Aggregate intrinsic value, ending	9,290,000	$ 807,000	$ 102,000
Aggregate intrinsic value for options fully vested and expected to vest	$ 9,138