Stock-Based Compensation - Employee Stock Purchase Plan (Details) - USD ($) |
12 Months Ended | ||
|---|---|---|---|
Jun. 05, 2017 |
Dec. 31, 2019 |
Dec. 31, 2018 |
|
| Employee Stock Purchase Plan | |||
| Percentage of purchase price to fair market value | 85.00% | ||
| Maximum payroll deduction amount per calendar year | $ 25,000 | ||
| Issuance of common stock in connection with employee stock purchase plan | $ 3,382,000 | $ 3,121,000 | |
| Available for future issuance under 2017 Employee Stock Purchase Plan (in shares) | 812,964 | ||
| Minimum | |||
| Employee Stock Purchase Plan | |||
| Percentage of payroll deduction | 1.00% | ||
| Maximum | |||
| Employee Stock Purchase Plan | |||
| Percentage of payroll deduction | 15.00% | ||
| Maximum shares of common stock issued under ESPP (in shares) | 1,000,000 | ||
| Common Stock | |||
| Employee Stock Purchase Plan | |||
| Maximum shares of common stock issued under ESPP (in shares) | 123,365 | 63,671 | |
| Employee Stock | |||
| Employee Stock Purchase Plan | |||
| Issuance of common stock in connection with employee stock purchase plan | $ 3,400,000 | ||