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Fair Value of Financial Instruments - Additional Information (Detail) - USD ($) | Dec. 31, 2020 | Dec. 31, 2019
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Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] |  |
Transfer of assets between Level 1 to Level 2 |  | $ 0
Transfer of assets between Level 2 to Level 1 |  | 0
Transfer of liabilities between Level 1 to Level 2 |  | 0
Transfer of liabilities between Level 2 to Level 1 |  | $ 0
Level 1 | Corporate notes and commercial paper |  |
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] |  |
Available-for-sale securities matured | $ 300,000 |

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