Property and Equipment, Net - Schedule of Property and Equipment, Net (Detail) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 138,883	$ 132,728
Less accumulated depreciation	(53,230)	(49,079)
Property and equipment, net	85,653	83,649
Computer Equipment and Purchased Software [Member]
Property, Plant and Equipment [Line Items]
Total property and equipment	12,843	13,028
Employee Related Computer Equipment [Member]
Property, Plant and Equipment [Line Items]
Total property and equipment	17,007	13,829
Furniture and Fixtures [Member]
Property, Plant and Equipment [Line Items]
Total property and equipment	18,330	14,319
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Total property and equipment	74,347	56,618
Equipment under Finance Lease [Member]
Property, Plant and Equipment [Line Items]
Total property and equipment	3,453	3,450
Internal Use Software [Member]
Property, Plant and Equipment [Line Items]
Total property and equipment	9,175	7,770
Construction in Progress [Member]
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 3,728	$ 23,714