Quarterly report pursuant to Section 13 or 15(d)

Stock Options - Range of Expected Volatilities for Options (Detail)

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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%