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 |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2019 |
Dec. 31, 2018 |
Dec. 31, 2017 |
|
| 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 | 10 | 10 | 10 |
| 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 | 1 | 1 | 2 |
| Warrants [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 | ||