17. SELECTED QUARTERLY CONSOLIDATED FINANCIAL DATA (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	May 31, 2013	Feb. 28, 2013	Nov. 30, 2012	Aug. 31, 2012	May 31, 2012	Feb. 29, 2012	Nov. 30, 2011	Aug. 31, 2011	May 31, 2013	May 31, 2012	May 31, 2011
Selected Quarterly Consolidated Financial Data Details
Net sales	$ 3,262	$ 3,340	$ 5,054	$ 4,832	$ 4,676	$ 2,855	$ 3,860	$ 4,130	$ 16,488	$ 15,521	$ 13,737
Gross profit	1,292	765	2,263	2,456	2,169	1,108	1,128	1,802	6,776	6,207	5,512
Net loss	$ (854)	$ (1,458)	$ (811)	$ (296)	$ (779)	$ (1,361)	$ (1,373)	$ 124	$ (3,419)	$ (3,390)	$ (3,389)
Net loss per share basic and diluted	$ (0.08)	$ (0.16)	$ (0.09)	$ (0.03)	$ (0.09)	$ (0.15)	$ (0.15)	$ 0.01	$ (0.36)	$ (0.38)	$ (0.39)