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Balance Sheet Components - Summary of Contractual Maturities Available-for-Sale Investments and Term Deposit (Detail) - USD ($) $ in Thousands | Dec. 31, 2019 | Dec. 31, 2018
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Available For Sale Securities Debt Maturities [Abstract] |  |
Within one year | $ 407,491 |
After one year through four years | 50,047 |
Total debt investments | 457,538 |
Bond and mutual funds | 10,816 |
Equity investments | 255 |
Total investments | $ 468,609 | $ 587,964

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