Stock-Based Compensation - Estimated Fair Value of Stock Options (Details) |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2020 |
Dec. 31, 2019 |
Dec. 31, 2018 |
|
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||
| Expected dividend yield | 0.00% | 0.00% | |
| Minimum | |||
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||
| Risk-free interest rate | 0.30% | 1.70% | 2.72% |
| Volatility | 54.40% | 52.90% | 44.87% |
| Expected term (in years) | 5 years 3 months 18 days | 6 years 1 month 6 days | 6 years 1 month 2 days |
| Maximum | |||
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||
| Risk-free interest rate | 1.50% | 2.59% | 2.92% |
| Volatility | 59.70% | 55.07% | 54.61% |
| Expected term (in years) | 6 years 1 month 6 days | 6 years 1 month 13 days | 6 years 1 month 9 days |
| X | ||||||||||
- 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
|
| X | ||||||||||
- 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
|
| X | ||||||||||
- 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
|
| X | ||||||||||
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
|
| X | ||||||||||
- 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
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|