Stock Based Compensation - Summary of Stock Option Grants (Detail) |
12 Months Ended | |
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Dec. 31, 2018 |
Dec. 31, 2017 |
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| Share-based Compensation Arrangement by Share-based Payment Award, Stock Options/Shares Outstanding, Weighted-Average Exercise Price, and Additional Disclosures [Abstract] | ||
| Risk-free interest rate | 2.79% | 2.03% |
| Expected volatility | 49.66% | 47.00% |
| Expected dividend yield | 0.00% | 0.00% |
| Expected term (in years) | 5 years 8 months 23 days | 6 years 29 days |
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- Definition Share-based compensation arrangement by share-based payment award, stock options/shares outstanding, weighted-average exercise price, and additional disclosures. 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 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://fasb.org/us-gaap/role/ref/legacyRef
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