Stock Options and Warrants - Estimated Fair Value of Options and Warrants Determined Using Black-Scholes Option Valuation Model with Weighted-Average Assumptions (Detail) - USD ($) |
12 Months Ended | |||
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Feb. 06, 2015 |
Sep. 26, 2014 |
May. 31, 2015 |
May. 31, 2014 |
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| Share Based Compensation Arrangements By Share Based Payment Award Options [Line Items] | ||||
| Risk free rate, minimum | 0.73% | 0.52% | ||
| Risk free rate, maximum | 1.10% | 1.85% | ||
| Dividend yield | $ 0 | $ 0 | ||
| Volatility, minimum | 74.36% | 78.73% | ||
| Volatility, maximum | 81.16% | 92.92% | ||
| Expected term | 5 years | 5 years | ||
| Minimum | ||||
| Share Based Compensation Arrangements By Share Based Payment Award Options [Line Items] | ||||
| Expected term | 2 years 6 months | 2 years 6 months | ||
| Grant-date fair value | $ 0.33 | $ 0.40 | ||
| Maximum | ||||
| Share Based Compensation Arrangements By Share Based Payment Award Options [Line Items] | ||||
| Expected term | 3 years 6 months | 3 years 6 months | ||
| Grant-date fair value | $ 0.60 | $ 0.67 | ||
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- Definition Share Based Compensation Arrangements By Share Based Payment Award Options [Line Items] No definition available.
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- Definition 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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- Definition The estimated measure of the minimum 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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- Definition The maximum risk-free interest rate assumption that is used in valuing an option on its own shares. No definition available.
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- Definition The minimum risk-free interest rate assumption that is used in valuing an option on its own shares. No definition available.
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- Definition Disclosure of the weighted average expected dividend for an entity using a valuation technique with different dividend rates during the contractual term. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Price of a single share of a number of saleable stocks of a company. No definition available.
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- Definition Expected term of share-based compensation awards, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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