Quarterly report pursuant to Section 13 or 15(d)

Property and Equipment - Additional Information (Detail)

v3.8.0.1
Property and Equipment - Additional Information (Detail) - USD ($)
$ in Millions
3 Months Ended
Mar. 31, 2018
Mar. 31, 2017
Property, Plant and Equipment [Line Items]    
Depreciation expense $ 0.1 $ 0.1