Significant Inputs and Assumptions Used in Binomial Lattice Model for Derivative Liability (Detail) - $ / shares |
6 Months Ended | ||||||||
|---|---|---|---|---|---|---|---|---|---|
Sep. 15, 2016 |
Jun. 23, 2015 |
May 31, 2015 |
Apr. 30, 2015 |
Feb. 06, 2015 |
Sep. 26, 2014 |
Nov. 30, 2016 |
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| Fair Value Inputs, Liabilities, Quantitative Information [Line Items] | |||||||||
| Contractual conversion rate | $ 0.78 | $ 0.67 | |||||||
| Adjusted conversion price | $ 0.675 | ||||||||
| Contractual term to maturity (years) | 5 years | 4 years 9 months 15 days | |||||||
| Expected volatility | 106.00% | 103.00% | |||||||
| Risk-free rate | 1.20% | 1.81% | |||||||
| Derivative Liability | |||||||||
| Fair Value Inputs, Liabilities, Quantitative Information [Line Items] | |||||||||
| Quoted market price on valuation date | $ 0.90 | $ 0.99 | $ 0.96 | $ 0.79 | |||||
| Contractual conversion rate | 1.00 | 1.00 | 1.00 | 1.00 | |||||
| Adjusted conversion price | [1] | $ 0.6750 | $ 0.6750 | $ 1.0000 | $ 0.9759 | ||||
| Contractual term to maturity (years) | 1 month 13 days | 5 months 27 days | 2 years | ||||||
| Expected volatility | 48.00% | 124.00% | 123.00% | ||||||
| Contractual interest rate | 1.20% | 2.00% | 5.00% | ||||||
| Risk-free rate | 0.001% | 0.045% | 0.59% | ||||||
| Risk adjusted rate | 2.80% | 2.80% | 2.78% | 2.69% | |||||
| Probability of event of default | 5.00% | 5.00% | 5.00% | 5.00% | |||||
| Derivative Liability | Minimum | |||||||||
| Fair Value Inputs, Liabilities, Quantitative Information [Line Items] | |||||||||
| Contractual term to maturity (years) | 2 months 5 days | ||||||||
| Expected volatility | 90.00% | ||||||||
| Contractual interest rate | 1.50% | ||||||||
| Risk-free rate | 0.041% | ||||||||
| Derivative Liability | Maximum | |||||||||
| Fair Value Inputs, Liabilities, Quantitative Information [Line Items] | |||||||||
| Contractual term to maturity (years) | 1 year 3 months 29 days | ||||||||
| Expected volatility | 114.00% | ||||||||
| Contractual interest rate | 5.00% | ||||||||
| Risk-free rate | 0.48% | ||||||||
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