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Investments in Marketable Securities - Additional Information (Detail) $ in Thousands | 3 Months Ended | 12 Months Ended
--- | --- | ---
Mar. 31, 2020 USD ($) | Dec. 31, 2019 USD ($)
Schedule of Available-for-sale Securities [Line Items] |  |
Available-for-sale, securities in unrealized loss positions, accumulated loss | $ 1,046 | $ 22
Allowance for credit losses | $ 0 |
Weighted average contractual maturity | 1 year 9 months 18 days | 1 year 8 months 12 days
Fitch, AA+ Rating [Member] | Moody's, Aaa Rating [Member] | Standard & Poor's, AA+ Rating [Member] |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Weighted average contractual maturity | 1 year 9 months 18 days |
Fitch, A Rating [Member] | Moody's, A1 Rating [Member] | Weighted Average Credit A Rating [Member] |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Available-for-sale, securities number of positions | 54 |
Available-for-sale, securities in unrealized loss positions, accumulated loss | $ 1,000 |
Percentage of amortized cost | 0.60% |

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