Information about Geographic Areas - Classification of Revenue by Geography (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	$ 24,999	$ 34,592	$ 48,084	$ 52,656
Americas
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	17,005	27,341	32,833	39,552
Europe & Middle East
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	6,392	5,237	12,150	9,653
Asia Pacific
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	$ 1,602	$ 2,014	$ 3,101	$ 3,451