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 9 Months Ended
Sep. 30, 2017
Sep. 30, 2016
Sep. 30, 2017
Sep. 30, 2016
Property, Plant and Equipment [Abstract]        
Total depreciation expense recorded $ 0.1 $ 0.1 $ 0.4 $ 0.4