Note 6 - Stock Compensation Plan - BSM Option Valuation Model Assumptions (Details) - Employee Stock Option [Member] - $ / shares |
9 Months Ended | |
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Sep. 30, 2016 |
Sep. 30, 2015 |
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Minimum [Member] | ||
Risk-free interest rate | 0.52% | 1.34% |
Volatility | 66.20% | 58.90% |
Maximum [Member] | ||
Risk-free interest rate | 1.38% | 1.94% |
Volatility | 75.40% | 67.80% |
Weighted-average volatility | 73.90% | 60.10% |
Dividend yield | 0.00% | 0.00% |
Contractual term (in years) | 1 year 292 days | 6 years |
Weighted-average grant date fair value per share (in dollars per share) | $ 0.17 | $ 0.91 |
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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 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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- Definition Weighted average expected volatility rate of share-based compensation awards. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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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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- 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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