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Summary of Significant Accounting Policies - Stock-Based Compensation - Fair Value of Each Stock Option Granted (Details) (Stock Option Plan, USD $)
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12 Months Ended | ||
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Apr. 30, 2014
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Apr. 30, 2013
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Apr. 30, 2012
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Stock Option Plan
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| Expected life (years) | — | 3.0 to 5.75 | 3.0 to 3.3 |
| Expected volatility | 77.00% | 77.00% | |
| Expected dividend yield | |||
| Expected forfeiture rate | 5.00% | 5.00% | |
| Risk-free interest rate minimum | 0.50% | 0.50% | |
| Risk-free interest rate maximum | 0.60% | 0.60% | |
| Weighted average fair value of options granted during the year | $ 0.90 | $ 0.56 | |
| X | ||||||||||
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- Definition
No authoritative reference available. No definition available.
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- Definition
The estimated dividend rate (a percentage of the share price) to be paid (expected dividends) to holders of the underlying shares over the option's term. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition
Discloses use of the simplified method to calculate the expected term that stock option awards under the specified plan will exist before being exercised or terminated, the reason and justification for its use, and the periods for which the method was used if it was not used in all periods presented. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition
The estimated measure of the 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. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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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
The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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