Quarterly report pursuant to Section 13 or 15(d)

Property and Equipment - Additional Information (Detail)

v3.7.0.1
Property and Equipment - Additional Information (Detail) - USD ($)
$ in Thousands
3 Months Ended 6 Months Ended
Jun. 30, 2017
Jun. 30, 2016
Jun. 30, 2017
Jun. 30, 2016
Dec. 31, 2016
Property, Plant and Equipment [Line Items]          
Gross property and equipment $ 12,334   $ 12,334   $ 11,726
Depreciation expense 134 $ 15 268 $ 69  
Asset Under Construction [Member]          
Property, Plant and Equipment [Line Items]          
Gross property and equipment $ 530   $ 530   $ 37