Information about Geographic Areas - Classification of Revenue by Geography (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	$ 23,085	$ 18,063
Americas
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	15,828	12,211
Europe & Middle East
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	5,758	4,415
Asia Pacific
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	$ 1,499	$ 1,437