Stock-based Compensation - Purchase Plan (Details) - Purchase Plan $ in Millions |
9 Months Ended | |
|---|---|---|
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Sep. 30, 2018
USD ($)
item
shares
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Sep. 30, 2017 |
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| Additional disclosures | ||
| Award offering period | 24 months | |
| Number of purchase periods per award offering period | item | 4 | |
| Award purchase period | 6 months | |
| Purchase price expressed as a percentage of fair market value of common stock on the purchase date | 85.00% | |
| Purchase price expressed as a percentage of fair market value of common stock on the first day of the offering period | 85.00% | |
| Shares reserved for future issuance | shares | 1,790,451 | |
| Unrecognized compensation cost related to purchase plan | $ | $ 1.6 | |
| Weighted-average assumptions relating to Purchase Plan | ||
| Risk-free interest rate (as a percent) | 2.40% | 0.60% |
| Expected term (in years) | 1 year 3 months 18 days | 1 year 9 months 18 days |
| Dividend yield (as a percent) | 0.00% | 0.00% |
| Expected volatility (as a percent) | 66.20% | 64.60% |
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- Definition Represents the offering period for awards under the equity-based compensation plan. No definition available.
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- Definition Represents the purchase period for awards under the equity-based compensation plan. No definition available.
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- Definition Represents the number of purchase periods per award offering period under the equity-based compensation plan. No definition available.
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- Definition Represents the purchase price expressed as a percentage of the fair market value of common stock on the first day of the offering period. No definition available.
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- Definition Aggregate number of common shares reserved for future issuance. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Unrecognized cost of unvested share-based awards, other than options, awarded to employees as compensation. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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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://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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- References No definition available.
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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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- Definition Purchase price of common stock expressed as a percentage of its fair value. No definition available.
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- Details
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