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Convertible Instruments - Additional Information (Detail) (USD $)
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3 Months Ended | 12 Months Ended | 118 Months Ended | 3 Months Ended | 12 Months Ended | ||||||||||||
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Aug. 31, 2013
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May 31, 2013
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Aug. 31, 2013
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Aug. 31, 2013
US Phase III trial
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Aug. 31, 2013
US new drug application approval by the FDA
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Aug. 31, 2013
Investor
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May 31, 2013
Investor
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May 31, 2013
Minimum
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Aug. 31, 2013
Minimum
Investor
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May 31, 2013
Minimum
Investor
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May 31, 2013
Maximum
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Aug. 31, 2013
Maximum
Investor
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May 31, 2013
Maximum
Investor
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May 31, 2010
Series B convertible preferred stock
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Aug. 31, 2013
Series B convertible preferred stock
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May 31, 2010
Common Stock
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Apr. 30, 2010
Common Stock
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| Class of Stock [Line Items] | |||||||||||||||||
| Preferred Stock, Shares issued | 95,100 | 95,100 | 95,100 | 400,000 | |||||||||||||
| Preferred Stock, Share issuance price | $ 1.30 | $ 1.30 | $ 5.00 | ||||||||||||||
| Cash proceeds | $ 2,009,000 | ||||||||||||||||
| Preferred stock shares outstanding | 95,100 | 95,100 | 95,100 | 95,100 | |||||||||||||
| Number of common shares issued upon conversion of preferred stock | 10 | ||||||||||||||||
| Convertible note conversion price per share | $ 0.75 | $ 0.65 | $ 0.50 | ||||||||||||||
| Common stock shares authorized for issuance | 100,000,000 | 100,000,000 | 100,000,000 | 100,000,000 | |||||||||||||
| Constructive dividend to Preferred stock holders | 6,000,000 | ||||||||||||||||
| Liquidation preference on common shares | 5.00 | 5.00 | |||||||||||||||
| Dividends are payable to preferred stock holders | $ 0.25 | ||||||||||||||||
| Face amount of notes | 1,200,000 | 6,588,250 | 1,200,000 | ||||||||||||||
| Convertible note, conversion amount | 4,721,250 | 1,580,000 | |||||||||||||||
| Earliest date for repayment of principal on notes | Nov. 30, 2013 | ||||||||||||||||
| Latest date for repayment of principal on notes | Mar. 06, 2016 | ||||||||||||||||
| Interest rate on convertible notes | 5.00% | 10.00% | |||||||||||||||
| Interest on convertible notes payment start date | Apr. 01, 2013 | ||||||||||||||||
| Common stock warrant term | 2 years | 3 years | |||||||||||||||
| Warrants to purchase common shares, shares | 9,451,056 | ||||||||||||||||
| Warrants exercise price per share | 0.75 | 0.75 | 0.50 | 2.00 | |||||||||||||
| Amortization expense | $ 1,452,000 | $ 0 | $ 3,156,000 | ||||||||||||||