2. STOCK-BASED COMPENSATION (Details Narrative) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Nov. 30, 2013	Nov. 30, 2012	Nov. 30, 2013	Nov. 30, 2012
Stock-based compensation costs capitalized as part of inventory	$ 0	$ 67	$ 0	$ 67
Stock-based compensation related to stock options	193	83	328	192
Intrinsic value of options exercised	110	0	153	42
Weighted average remaining contractual life of the options exercisable and expected to be exercisable			4 years 5 months 26 days
1996 Stock Option Plan and 2006 Equity Incentive Plan
Unrecognized stock-based compensation cost related to unvested stock-based awards	1,218		1,218
Estimated forfeitures of unvested stock based awards	3		3
Weighted average remaining period of the underlying options			2 years 10 months 24 days
Employee Stock Purchase Plan
Stock-based compensation related to the ESPP	54	16	62	34
Weighted average remaining period of the underlying options			1 year 2 months 12 days
Compensation cost related to options to purchase the Company's common stock under the ESPP but not yet recognized	$ 315		$ 315