XML 49 R38.htm IDEA: XBRL DOCUMENT v3.20.2
Short-term Investments - Narrative (Details)
3 Months Ended 9 Months Ended
Sep. 30, 2020
USD ($)
investment
Sep. 30, 2019
USD ($)
Sep. 30, 2020
USD ($)
investment
Sep. 30, 2019
USD ($)
Investments, Debt and Equity Securities [Abstract]        
Realized gain on investments $ 105,000 $ 155,000 $ 741,000 $ 330,000
Realized loss on investments 101,000 11,000 1,300,000 93,000
Net unrealized gain (loss) on available-for-sale equity securities $ 1,315,980 $ 0 $ 624,522 $ 0
Number of securities in a gross unrealized loss position | investment 11   11  
Number of securities in a gross unrealized loss position for more than twelve months | investment 0   0