1. ORGANIZATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details 2) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	May 31, 2017	May 31, 2016	May 31, 2015
Stock-based compensation in the form of employee stock options, RSUs and ESPP purchase rights included in:
Total stock-based compensation	$ 999	$ 1,016	$ 997
Effect on net loss per share, Basic	$ 0.06	$ 0.08	$ 0.08
Effect on net loss per share, Diluted	$ 0.06	$ 0.08	$ 0.08
Cost Of Sales
Stock-based compensation in the form of employee stock options, RSUs and ESPP purchase rights included in:
Total stock-based compensation	$ 91	$ 87	$ 70
Selling, General and Administrative
Stock-based compensation in the form of employee stock options, RSUs and ESPP purchase rights included in:
Total stock-based compensation	714	723	726
Research And Development
Stock-based compensation in the form of employee stock options, RSUs and ESPP purchase rights included in:
Total stock-based compensation	$ 194	$ 206	$ 201