Short-term Investments - Additional Information (Detail) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Summary Of Investment Holdings [Line Items]
Short-term investments	$ 0	$ 108,919
US Treasury Securities
Summary Of Investment Holdings [Line Items]
Available-for-sale securities, amortized cost		108,800
Available-for-sale securities, fair value		108,900
Available-for-sale securities, unrealized loss position		$ 0

Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amount of investments including trading securities, available-for-sale securities, held-to-maturity securities, and short-term investments classified as other and current.

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