Condensed Consolidated Statements of Operations (Unaudited) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Nov. 30, 2011	Nov. 30, 2010	Nov. 30, 2011	Nov. 30, 2010
Condensed Consolidated Statements Of Operations
Net sales	$ 3,860	$ 3,577	$ 7,990	$ 5,746
Cost of sales	2,732	2,223	5,060	3,448
Gross profit	1,128	1,354	2,930	2,298
Operating expenses:
Selling, general and administrative	1,528	1,495	3,129	3,013
Research and development	1,039	1,196	2,121	2,338
Gain on bankruptcy claim	0	0	0	(155)
Total operating expenses	2,567	2,691	5,250	5,196
Loss from operations	(1,439)	(1,337)	(2,320)	(2,898)
Interest income	0	1	0	3
Gain on sale of long-term investment	0	0	990	0
Other income, net	58	579	46	623
Loss before income tax (benefit) expense	(1,381)	(757)	(1,284)	(2,272)
Income tax (benefit) expense	(8)	10	(35)	11
Net loss	$ (1,373)	$ (767)	$ (1,249)	$ (2,283)
Net loss per share - basic	$ (0.15)	$ (0.09)	$ (0.14)	$ (0.26)
Net loss per share - diluted	$ (0.15)	$ (0.09)	$ (0.14)	$ (0.26)
Shares used in per share calculations:
Basic	8,980	8,731	8,956	8,699
Diluted	8,980	8,731	8,956	8,699