XML 14 R33.htm IDEA: XBRL DOCUMENT v3.19.3
Property and Equipment, net - Additional Information (Detail) - USD ($)
$ in Thousands
3 Months Ended 9 Months Ended
Sep. 30, 2019
Sep. 30, 2018
Sep. 30, 2019
Sep. 30, 2018
Property And Equipment [Abstract]        
Depreciation and amortization expense $ 44 $ 57 $ 139 $ 175