Geographic Information - Schedule of Geographic Information (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Segment Reporting Information [Line Items]
Total revenue	$ 30,305	$ 34,024	$ 59,435	$ 65,922
UNITED STATES
Segment Reporting Information [Line Items]
Total revenue	27,253	29,227	52,354	55,686
CANADA
Segment Reporting Information [Line Items]
Total revenue	2,272	2,989	5,147	6,740
Non-US [Member]
Segment Reporting Information [Line Items]
Total revenue	$ 780	$ 1,808	$ 1,934	$ 3,496