Segment Information (Revenue by Geographic Region) (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	$ 40,424	$ 44,248	$ 83,569	$ 83,720
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	20,785	21,322	43,205	40,292
Europe
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	14,524	17,097	29,362	32,481
Rest of the World
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	$ 5,115	$ 5,829	$ 11,002	$ 10,947