Property and Equipment by Geographic Area (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Revenues from External Customers and Long-Lived Assets [Line Items]
Total property and equipment, net	$ 63,301	$ 61,655
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Total property and equipment, net	47,219	46,605
India
Revenues from External Customers and Long-Lived Assets [Line Items]
Total property and equipment, net	4,217	4,176
EMEA
Revenues from External Customers and Long-Lived Assets [Line Items]
Total property and equipment, net	8,148	7,120
Other international
Revenues from External Customers and Long-Lived Assets [Line Items]
Total property and equipment, net	$ 3,717	$ 3,754