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10. Stock-Based Compensation (Details 3) - $ / shares | 12 Months Ended
--- | ---
Dec. 31, 2018 | Dec. 31, 2017
Risk-free interest rate | 2.25% | 1.32%
Expected volatility | 92.20% | 68.50%
Market value per share on grant date | $ 1.05 | $ 1.43
Fair value per share on grant date | $ 1.04 | $ 1.42
SARs |  |
Risk-free interest rate | 2.60% |
Expected volatility | 125.00% |
Market value per share on grant date | $ .61 |
Fair value per share on grant date | $ 1.08 |

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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. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (f)(2)(ii) -URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901 + Details
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- Definition The risk-free interest rate assumption that is used in valuing an option on its own shares. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (f)(2)(iv) -URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901 + Details
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