Geographic Information - Schedule of Geographic Information (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Segment Reporting Information [Line Items]
Total revenue	$ 30,826	$ 31,184	$ 96,748	$ 88,289
UNITED STATES
Segment Reporting Information [Line Items]
Total revenue	26,654	26,992	82,342	75,603
CANADA
Segment Reporting Information [Line Items]
Total revenue	2,108	2,804	8,847	8,396
Non-US [Member]
Segment Reporting Information [Line Items]
Total revenue	$ 2,064	$ 1,388	$ 5,559	$ 4,290