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Short-term Investments - Additional Information (Detail) - US Treasury Securities - USD ($) $ in Thousands | Mar. 31, 2020 | Dec. 31, 2019
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Summary Of Investment Holdings [Line Items] |  |
Available-for-sale securities, amortized cost | $ 109,200 | $ 108,800
Available-for-sale securities, fair value | 109,900 | 108,900
Available-for-sale securities, unrealized loss position | $ 0 | $ 0

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