Property and Equipment Net - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Property, Plant and Equipment [Line Items]
Property and equipment, depreciation and amortization expense	$ 1,100,000	$ 1,100,000	$ 700,000
Impairment of long-lived assets	150,000	$ 0	$ 0
Construction-in-progress
Property, Plant and Equipment [Line Items]
Impairment of long-lived assets	$ 200,000