Stockholders' Equity - Schedule of Reserve Share of Common Stock for Issuance (Details) - shares |
Dec. 31, 2016 |
Dec. 31, 2015 |
Jul. 31, 2015 |
|---|---|---|---|
| Class Of Stock [Line Items] | |||
| Shares of common stock reserved for issuance | 30,595,000 | 27,307,000 | |
| Twenty Fifteen Equity Incentive Plan | |||
| Class Of Stock [Line Items] | |||
| Shares of common stock reserved for issuance | 11,081,000 | 12,006,000 | 11,400,000 |
| Twenty Fifteen Employee Stock Purchase Plan | |||
| Class Of Stock [Line Items] | |||
| Shares of common stock reserved for issuance | 2,511,000 | 1,000,000 | |
| Employee Stock Option | |||
| Class Of Stock [Line Items] | |||
| Shares of common stock reserved for issuance | 12,897,000 | 12,795,000 | |
| Restricted Stock Units (RSUs) | |||
| Class Of Stock [Line Items] | |||
| Shares of common stock reserved for issuance | 4,106,000 | 1,506,000 |