Investments - Summary of Cost and Fair Value of Investments Classified as Available-for-sale (Details) - USD ($) $ in Thousands |
Dec. 31, 2019 |
Dec. 31, 2018 |
|---|---|---|
| Schedule Of Available For Sale Securities [Line Items] | ||
| Available-for-sale securities, at fair value | $ 771 | $ 601 |
| Available For Sale Securities | ||
| Schedule Of Available For Sale Securities [Line Items] | ||
| Cost | 696 | 666 |
| Gross Unrealized gains | 85 | 6 |
| Gross Unrealized losses | (10) | (71) |
| Available-for-sale securities, at fair value | $ 771 | $ 601 |