XML 56 R37.htm IDEA: XBRL DOCUMENT v3.20.1
Short-term Investments - Narrative (Details)
3 Months Ended
Mar. 31, 2020
USD ($)
investment
Mar. 31, 2019
USD ($)
Investments, Debt and Equity Securities [Abstract]    
Realized gain on investments $ 50,000 $ 18,000
Realized loss on investments 525,000 53,000
Equity securities, unrealized gain (loss) $ (5,100,000) $ 0
Number of securities in a gross unrealized loss position | investment 25  
Number of securities in a gross unrealized loss position for more than twelve months | investment 2  
Unrealized loss $ 560,000