Stock Options - Range of Expected Volatilities for Options (Detail)	9 Months Ended
Aug. 31, 2013	Aug. 31, 2012
Service-Based Vesting Condition Options [Member]
Range of expected volatilities for options
Minimum expected volatility	108.75%	111.30%
Maximum expected volatility	114.99%	116.28%
Performance and Market-Based Vesting Condition Options [Member]
Range of expected volatilities for options
Minimum expected volatility		111.30%
Maximum expected volatility		113.50%

The estimated measure of the maximum 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.

No definition available.

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