XML 48 R37.htm IDEA: XBRL DOCUMENT v3.21.1
Financial Instruments - Additional Information (Details) - USD ($)
3 Months Ended
Mar. 31, 2021
Mar. 31, 2020
Financial Instruments Owned At Fair Value [Abstract]    
Realized gains or losses on available-for-sale investments $ 0 $ 0
Investments in continuous unrealized loss position for more than 12 months 0 0
Other-than-temporary impairment losses $ 0 $ 0