Investments - Additional Information (Details) |
3 Months Ended | 9 Months Ended | |||
---|---|---|---|---|---|
Sep. 30, 2020
USD ($)
|
Sep. 30, 2019
USD ($)
|
Sep. 30, 2020
USD ($)
|
Sep. 30, 2019
USD ($)
|
Dec. 31, 2019
USD ($)
Investment
|
|
Schedule Of Available For Sale Securities [Line Items] | |||||
Available-for-sale investments | $ 0 | $ 0 | $ 73,065,000 | ||
Realized gains or losses | $ 0 | $ 0 | $ 0 | ||
Maximum | |||||
Schedule Of Available For Sale Securities [Line Items] | |||||
Realized gains or losses | $ 100,000 | ||||
US Treasury Bonds | |||||
Schedule Of Available For Sale Securities [Line Items] | |||||
Available-for-sale investments | $ 73,065,000 | ||||
Number of investments in unrealized loss position for less than 12 months | Investment | 4 | ||||
Investments in unrealized loss position for less than 12 months, fair value | $ 18,000,000 |