Information about Geographic Areas - Additional Information (Detail) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015 USD ($)	Sep. 30, 2014 USD ($)	Sep. 30, 2015 USD ($) Segment	Sep. 30, 2014 USD ($)
Revenues from External Customers and Long-Lived Assets [Line Items]
Number of reportable segment | Segment			1
Total revenue	$ 15,693	$ 12,343	$ 40,352	$ 31,975
United States [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	$ 9,600	$ 7,000	$ 24,500	$ 19,200