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Property, Plant and Equipment - Additional Information (Detail) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Property, Plant and Equipment [Line Items]      
Depreciation expense $ 0.2   $ 0.1
Maximum      
Property, Plant and Equipment [Line Items]      
Depreciation expense   $ 0.1