Summary of Significant Accounting Policies - Schedule of Potentially Dilutive Shares that were Excluded from Computation of Diluted Net Income (Loss) per Share of Common Stock (Detail) - shares shares in Millions |
3 Months Ended | 9 Months Ended | ||
|---|---|---|---|---|
Sep. 30, 2020 |
Sep. 30, 2019 |
Sep. 30, 2020 |
Sep. 30, 2019 |
|
| Stock-based awards [Member] | ||||
| Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items] | ||||
| Potential common shares excluded from computation of net income (loss) per share | 1 | 37 | 0 | 61 |
| Convertible senior notes [Member] | ||||
| Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items] | ||||
| Potential common shares excluded from computation of net income (loss) per share | 0 | 5 | 1 | 5 |