Consolidated Statements of Operations (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	May 31, 2012	May 31, 2011	May 31, 2010
Consolidated Statements Of Operations
Product sales	$ 15,521	$ 13,737	$ 8,934
Cancellation charges	0	0	2,740
Total net sales	15,521	13,737	11,674
Cost of sales	9,314	8,225	5,571
Gross profit	6,207	5,512	6,103
Operating expenses:
Selling, general and administrative	6,526	5,964	6,094
Research and development	4,188	4,567	4,758
Gain on bankruptcy claim	0	(832)	(3,993)
Total operating expenses	10,714	9,699	6,859
Loss from operations	(4,507)	(4,187)	(756)
Interest income	0	3	5
Interest expense	(4)	0	0
Gain on sale of long-term investment	990	0	0
Other income, net	117	762	131
Loss before income tax benefit	(3,404)	(3,422)	(620)
Income tax benefit	15	49	139
Net loss	$ (3,389)	$ (3,373)	$ (481)
Net loss per share - basic	$ (0.38)	$ (0.38)	$ (0.06)
Shares used in per share calculation - basic	9,016	8,776	8,563
Net loss per share - diluted	$ (0.38)	$ (0.38)	$ (0.06)
Shares used in per share calculation - diluted	9,016	8,776	8,563