2. STOCK-BASED COMPENSATION (Details Narrative) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Feb. 28, 2015	Feb. 28, 2014	Feb. 28, 2015	Feb. 28, 2014
Stock-based compensation costs capitalized as part of inventory	$ 53	$ 0	$ 53	$ 0
Stock-based compensation expense related to stock options	183	205	589	533
Intrinsic value of options exercised	30	162	466	315
Weighted average remaining contractual life of the options exercisable and expected to be exercisable			4 years 6 months 4 days
Employee Stock Purchase Plan
Stock-based compensation related to the ESPP	37	30	104	92
Compensation cost related to options to purchase the Company's common stock under the ESPP but not yet recognized	111		111
Weighted average period for recognition of costs			1 year 2 months 12 days
ESPP purchase rights granted	0	0	170,000	163,000
ESPP shares issued	0	0	43,000	75,000
ESPP shares available for issuance	311,000		311,000
1996 Stock Option Plan and 2006 Equity Incentive Plan
Unrecognized stock-based compensation	1,540		1,540
Estimated forfeitures of unvested stock based awards, amount	$ 4		$ 4
Weighted average period for recognition of costs			2 years 8 months 12 days