Equity Incentive Plans, Employee Stock Purchase Plan and Stock-Based Compensation - Schedule of Fair Value of ESPP Shares Using Option Pricing Model (Details) |
12 Months Ended | ||
---|---|---|---|
Dec. 31, 2021 |
Dec. 31, 2020 |
Dec. 31, 2019 |
|
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] | |||
Expected volatility, Minimum | 80.90% | 73.20% | 72.70% |
Expected volatility, Maximum | 84.90% | 87.40% | 74.90% |
Risk-free interest rate, Minimum | 0.60% | 0.20% | 1.40% |
Risk-free interest rate, Maximum | 1.30% | 1.60% | 2.60% |
Expected dividend | 0.00% | ||
2018 Employee Stock Purchase Plan | |||
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] | |||
Expected term (in years) | 6 months | 6 months | 6 months |
Expected volatility, Minimum | 65.90% | 63.00% | 63.00% |
Expected volatility, Maximum | 111.40% | 111.40% | 83.20% |
Risk-free interest rate | 0.10% | ||
Risk-free interest rate, Minimum | 0.10% | 1.90% | |
Risk-free interest rate, Maximum | 1.90% | 2.50% |