Stock Option Plans - Schedule of Weighted-average Assumptions to Estimate the Fair Value of the Options Granted (Details) |
12 Months Ended | ||
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Dec. 31, 2019 |
Dec. 31, 2018 |
Dec. 31, 2017 |
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| Share-based Payment Arrangement [Abstract] | |||
| Expected volatility | 108.00% | 109.00% | 111.00% |
| Expected term | 5 years 1 month 6 days | 5 years | 5 years |
| Risk-free interest rate | 2.21% | 2.62% | 1.81% |
| Expected dividend yield | 0.00% | 0.00% | 0.00% |
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- References 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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