Note I - Stock Based Compensation (Detail) - Options valuation assumptions	6 Months Ended
Oct. 31, 2012	Oct. 31, 2011
Expected term (years)	5 years	5 years
Risk-free interest rate	0.78%	1.77%
Volatility	50.00%	50.00%

- Definition

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.

+ References+ Details