Information about Geographic Areas - Classification of Revenue by Geography (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	$ 27,688	$ 23,085
Americas
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	18,927	15,828
Europe & Middle East
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	7,200	5,758
Asia Pacific
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	$ 1,561	$ 1,499