Information about Geographic Areas - Classification of Revenue by Geography (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	$ 35,234	$ 27,016	$ 34,592	$ 18,063	$ 25,232	$ 23,933	$ 22,627	$ 14,697	$ 114,905	$ 86,489	$ 62,667
Americas
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue									86,099	60,330	41,265
Europe & Middle East
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue									21,791	18,497	14,807
Asia Pacific
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue									$ 7,015	$ 7,662	$ 6,595