Annual report pursuant to Section 13 and 15(d)

Property and Equipment - Additional Information (Detail)

v3.20.1
Property and Equipment - Additional Information (Detail) - USD ($)
12 Months Ended
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Property Plant And Equipment [Abstract]      
Depreciation $ 73,000 $ 91,000 $ 108,000
Net book value of property and equipment written off $ 100,000