2. STOCK-BASED COMPENSATION (Details Narrative) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Aug. 31, 2015	Aug. 31, 2014
Stock-based compensation costs capitalized as part of inventory	$ 0	$ 51
Stock-based compensation expense related to stock options	286	162
Intrinsic value of options exercised	$ 60	407
Weighted average remaining contractual life of the options exercisable and expected to be exercisable	4 years 8 months 12 days
Employee Stock Purchase Plan
Stock-based compensation related to the ESPP	$ 33	$ 35
Compensation cost related to purchase rights under the ESPP but not yet recognized	$ 101
Weighted average period for recognition of costs	1 year 2 months 12 days
ESPP purchase rights granted	0	0
1996 Stock Option Plan and 2006 Equity Incentive Plan
Unrecognized stock-based compensation	$ 1,610
Estimated forfeitures of unvested stock based awards, amount	$ 4
Weighted average period for recognition of costs	2 years 8 months 12 days
Restricted Stock Units
Restricted Stock Units granted	35,000
Market value on the date of the grant	$ 2.16