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2. STOCK-BASED COMPENSATION (Details 2) (Employee Stock Purchase Plan, USD $)	9 Months Ended
	Feb. 29, 2012
Minimum
Expected term (in years)	6 months
Volatility	0.79%
Expected dividend	$ 0
Risk-free Interest Rates	0.10%
Estimated Forfeiture Rate	0.00%
Weighted Average Grant Date Fair Value	$ 0.40
Maximum
Expected term (in years)	2 years
Volatility	0.98%
Expected dividend	$ 0
Risk-free Interest Rates	1.10%
Estimated Forfeiture Rate	0.00%
Weighted Average Grant Date Fair Value	$ 0.40

The estimated measure of the percentage by which a share price is expected to fluctuate during a period. Volatility also may be defined as a probability-weighted measure of the dispersion of returns about the mean. The volatility of a share price is the standard deviation of the continuously compounded rates of return on the share over a specified period. That is the same as the standard deviation of the differences in the natural logarithms of the stock prices plus dividends, if any, over the period.

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