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Stock options and warrants (Schedule of Fair Value Assumptions) (Details) (Stock Options [Member])
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9 Months Ended | |
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Sep. 30, 2013
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Sep. 30, 2012
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| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||
| Dividend yield | 0.00% | 0.00% |
| Expected term | 5 years | 5 years |
| Forfeiture rate | 15.00% | 15.00% |
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Minimum [Member]
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| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||
| Expected price volatility | 127.00% | 121.00% |
| Risk free interest rate | 0.65% | 0.60% |
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Maximum [Member]
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| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||
| Expected price volatility | 128.00% | 145.00% |
| Risk free interest rate | 0.76% | 1.03% |
| X | ||||||||||
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- Definition
The forfeiture rate assumption that is used in valuing an option on its own shares. No definition available.
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| X | ||||||||||
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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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| X | ||||||||||
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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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| X | ||||||||||
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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 risk-free interest rate assumption that is used in valuing an option on its own shares. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Details
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