1. ORGANIZATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details 1) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	May 31, 2016	May 31, 2015	May 31, 2014
Stock-based compensation in the form of employee stock options and ESPP purchase rights included in:
Total stock-based compensation	$ 1,016	$ 997	$ 853
Effect on net (loss) income per share, Basic	$ .08	$ .08	$ .08
Effect on net (loss) income per share, Diluted	$ .08	$ .08	$ .07
Cost Of Sales
Stock-based compensation in the form of employee stock options and ESPP purchase rights included in:
Total stock-based compensation	$ 87	$ 70	$ 43
Selling, General and Administrative
Stock-based compensation in the form of employee stock options and ESPP purchase rights included in:
Total stock-based compensation	723	726	643
Research And Development
Stock-based compensation in the form of employee stock options and ESPP purchase rights included in:
Total stock-based compensation	$ 206	$ 201	$ 167