XML 32 R51.htm IDEA: XBRL DOCUMENT v3.20.1
Available-for-Sale Securities - Additional Information (Details) - USD ($)
12 Months Ended
Dec. 31, 2019
Dec. 31, 2018
Investments Debt And Equity Securities [Abstract]    
Unrealized gain on short and long-term investments $ 2,299 $ (2,308)
Other-than-temporary impairment $ 0