Property and Equipment, Net - Property and Equipment, Net (Detail) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Revenues from External Customers and Long-Lived Assets [Line Items]
Property and equipment, net	$ 25,826	$ 266,557
United States [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Property and equipment, net	16,133	262,844
India [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Property and equipment, net	5,255	967
United Kingdom [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Property and equipment, net	3,223	1,713
All Other Countries [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Property and equipment, net	$ 1,215	$ 1,033