Marketable Securities - Additional Information (Detail) - USD ($) |
3 Months Ended | 12 Months Ended |
---|---|---|
Mar. 31, 2020 |
Dec. 31, 2019 |
|
Marketable Securities [Line Items] | ||
Realized gains or losses on marketable securities | $ 0 | $ 0 |
Investments that matured beyond five years | $ 0 | $ 0 |
Minimum [Member] | ||
Marketable Securities [Line Items] | ||
Available-for-sales Securities, non-current, maturity period | 1 year | |
Maximum [Member] | ||
Marketable Securities [Line Items] | ||
Available-for-sales Securities, non-current, maturity period | 5 years |