Note 12 - Share-based Compensation - Stock Option Assumptions (Details) - $ / shares |
12 Months Ended | |
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Dec. 31, 2021 |
Dec. 31, 2020 |
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| Expected dividend yield | 0.00% | 0.00% |
| Minimum [Member] | ||
| Common share fair value (in dollars per share) | $ 3.64 | $ 4.08 |
| Risk-free interest rate | 0.50% | 0.30% |
| Expected option life (years) (Year) | 5 years | 5 years |
| Expected stock price volatility | 94.70% | 94.40% |
| Maximum [Member] | ||
| Common share fair value (in dollars per share) | $ 10.04 | $ 6.91 |
| Risk-free interest rate | 1.30% | 1.30% |
| Expected option life (years) (Year) | 5 years 6 months | 5 years 2 months 12 days |
| Expected stock price volatility | 106.10% | 102.20% |
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- Definition Agreed-upon price for the exchange of the underlying asset relating to the share-based payment award. 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://fasb.org/us-gaap/role/ref/legacyRef
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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://fasb.org/us-gaap/role/ref/legacyRef
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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://fasb.org/us-gaap/role/ref/legacyRef
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- Definition Expected term of award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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