XML 55 R43.htm IDEA: XBRL DOCUMENT v3.21.1
Financial Statement Details - Interest and Interest and Investment Income, Net (Detail) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Financial Statement Details [Abstract]    
Interest income $ 1,725 $ 2,764
Unrealized gain (loss) from equity securities 1,577 (321)
Investment (amortization expense) accretion income, net (858) 3
Net realized (losses) on investments (9) (4)
Investment income, net $ 2,435 $ 2,442