Equity Incentive Plans - Schedule of Fair Value of Stock Option Grants Valuation Assumptions by Block-Scholes Option Pricing Model (Details) - $ / shares |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2018 |
Dec. 31, 2017 |
Dec. 31, 2016 |
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| Share Based Compensation Arrangement By Share Based Payment Award [Line Items] | |||
| Expected term (in years) | 6 years | ||
| Expected volatility | 55.00% | 55.00% | |
| Expected dividend yield | 0.00% | ||
| Risk-free interest rate, minimum | 2.60% | 1.85% | 0.75% |
| Risk-free interest rate, maximum | 3.00% | 2.29% | 1.77% |
| Minimum | |||
| Share Based Compensation Arrangement By Share Based Payment Award [Line Items] | |||
| Fair value of common stock | $ 23.72 | $ 3.06 | $ 0.85 |
| Expected term (in years) | 5 years | 2 years | |
| Expected volatility | 64.00% | ||
| Maximum | |||
| Share Based Compensation Arrangement By Share Based Payment Award [Line Items] | |||
| Fair value of common stock | $ 47.39 | $ 19.56 | $ 3.06 |
| Expected term (in years) | 6 years | 10 years | |
| Expected volatility | 67.00% | ||
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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 maximum risk-free interest rate assumption that is used in valuing an option on its own shares. No definition available.
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- Definition The minimum risk-free interest rate assumption that is used in valuing an option on its own shares. No definition available.
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- 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.
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- Definition Price of a single share of a number of saleable stocks of a company. 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://fasb.org/us-gaap/role/ref/legacyRef
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