Stockholders' Equity (Deficit) - Schedule of Reserved Shares of Common Stock for Issuance (Details) shares in Thousands |
Dec. 31, 2018
shares
|
|---|---|
| Class Of Stock [Line Items] | |
| Total reserved shares of common stock | 33,296 |
| Equity Incentive Plan | |
| Class Of Stock [Line Items] | |
| Common stock awards granted under equity incentive plans | 20,057 |
| Common stock awards available for grant under equity incentive plan | 13,239 |