10. STOCKHOLDERS' EQUITY, COMPREHENSIVE INCOME AND STOCK-BASED COMPENSATION (Details Narrative) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	May 31, 2019	May 31, 2018	May 31, 2017
Total intrinsic values of options exercised	$ 338	$ 1,058	$ 810
Weighted average contractual life of the options exercisable and expected to be exercisable	3 years 5 months 16 days
Exercisable options to purchase (in thousands)	2,314	2,312	2,422
Weighted average exercise prices	$ 2.14	$ 1.89	$ 1.63
Restricted Stock Units granted (in thousands)	0	64	74
Market value on the date of the grant		$ 3.93	$ 1.68
RSUs vested (in thousands)	16	16	42
RSUs unvested (in thousands)	23	47	32
Intrinsic value of RSUs, nonvested	$ 40	$ 122	$ 145
2016 Equity Incentive Plan
Unrecognized stock-based compensation	1,182
Estimated forfeitures of unvested stock based awards, amount	$ 3
Weighted average period for recognition of costs	3 years
Shares reserved for issuance (in thousands)	2,238
Authorized shares (in thousands)	4,277	4,718
Outstanding shares (in thousands)	3,129	2,906
Employee Stock Purchase Plan
Unrecognized stock-based compensation	$ 179	$ 306
Weighted average period for recognition of costs	1 year 2 months 12 days
Stock-based compensation related to the ESPP	$ 255	290	115
Maximum calendar year contribution per employee	$ 25	$ 25	$ 25
Maximum number of shares a participant may purchase (in thousands)	3
ESPP purchase right granted (in thousands)	379	359	1
ESPP shares issued (in thousands)	125	237	151
Total shares issued under ESPP plan (in thousands)	1,481
ESPP Shares available for issuance (in thousands)	369
2006 Equity Incentive Plan
Shares remained available under plan (in thousands)	1,438
Board Of Directors
Restricted Stock Units granted (in thousands)	0	0	83
Market value on the date of the grant			$ 1.86
Stock Option and RSU
Stock-based compensation expense related to stock options and RSUs	$ 650	$ 706	$ 884
RSUs cancelled (in thousands)	8	33