Property and Equipment - Components of Property and Equipment (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 118,376	$ 114,073
Less: accumulated depreciation and amortization	(57,534)	(51,342)
Property and equipment, net	60,842	62,731
Hosting equipment
Property Plant And Equipment [Line Items]
Property and equipment, gross	36,410	35,018
Leasehold improvements
Property Plant And Equipment [Line Items]
Property and equipment, gross	26,727	25,396
Capitalized internal-use software
Property Plant And Equipment [Line Items]
Property and equipment, gross	26,553	25,773
Computer equipment and software
Property Plant And Equipment [Line Items]
Property and equipment, gross	12,766	11,879
Furniture and fixtures
Property Plant And Equipment [Line Items]
Property and equipment, gross	8,752	8,014
Construction in progress
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 7,168	$ 7,993