Marketable Securities and Fair Value Measurements - Additional Information (Detail) - USD ($) |
9 Months Ended | |
|---|---|---|
Sep. 30, 2020 |
Sep. 30, 2019 |
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| Investments Debt And Equity Securities [Abstract] | ||
| Proceeds from sale of available-for-sale securities | $ 0 | $ 1,300,000 |
| X | ||||||||||
- References No definition available.
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| X | ||||||||||
- Definition Amount of cash inflow from sale of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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