Note 10 - Stock-based Compensation - Stock Option Fair Value Assumptions (Details) - USD ($) |
12 Months Ended | ||
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Dec. 31, 2017 |
Dec. 31, 2016 |
Dec. 31, 2015 |
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Statement Line Items [Line Items] | |||
Risk-free interest rate | 1.32% | 0.68% | 1.17% |
Expected dividend yield | |||
Expected volatility | 98.00% | 110.00% | 106.00% |
Expected life of options (years) | 5 | 5 | 5 |
Grant date fair value (2016 and 2015 values have been recast to US dollars -note 3(b)) | $ 0.87 | $ 2.30 | $ 4.36 |
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- References No definition available.
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- Definition The expected volatility of the share price used to calculate the fair value of the share options granted. Expected volatility is a measure of the amount by which a price is expected to fluctuate during a period. The measure of volatility used in option pricing models is the annualised standard deviation of the continuously compounded rates of return on the share over a period of time. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition The option life of share options granted. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition The implied yield currently available on zero-coupon government issues of the country in whose currency the exercise price for share options granted is expressed, with a remaining term equal to the expected term of the option being valued (based on the option's remaining contractual life and taking into account the effects of expected early exercise). [Refer: Government [member]] Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition The amount of an expected dividend used to calculate the fair value of share options granted. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition The weighted average fair value of share options granted during the period at the measurement date. [Refer: Weighted average [member]] Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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