Segment Information (Long-Lived Assets by Geographic Region) (Detail) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	$ 27,735	$ 29,526
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	18,889	20,515
Europe
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	7,475	7,221
Rest of the World
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	$ 1,371	$ 1,790