1. ORGANIZATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details 1) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	May. 31, 2015	May. 31, 2014	May. 31, 2013
Stock-based compensation in the form of employee stock options and ESPP purchase rights included in:
Total stock-based compensation	$ 997	$ 853	$ 601
Effect on net (loss) income per share, Basic	$ .08	$ .08	$ .06
Effect on net (loss) income per share, Diluted	$ .08	$ .07	$ .06
Cost Of Sales
Stock-based compensation in the form of employee stock options and ESPP purchase rights included in:
Total stock-based compensation	$ 70	$ 43	$ 36
Selling, General and Administrative
Stock-based compensation in the form of employee stock options and ESPP purchase rights included in:
Total stock-based compensation	726	643	446
Research And Development
Stock-based compensation in the form of employee stock options and ESPP purchase rights included in:
Total stock-based compensation	$ 201	$ 167	$ 119