Property and Equipment - Components of Property and Equipment (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Property Plant And Equipment [Line Items]
Total	$ 142,967	$ 134,045
Less: accumulated depreciation and amortization	(81,967)	(74,888)
Property and equipment, net	61,000	59,157	[1]
Hosting equipment
Property Plant And Equipment [Line Items]
Total	36,410	37,222
Capitalized internal-use software
Property Plant And Equipment [Line Items]
Total	33,103	31,593
Leasehold improvements
Property Plant And Equipment [Line Items]
Total	29,066	28,113
Computer equipment and licensed software and patents
Property Plant And Equipment [Line Items]
Total	17,955	16,316
Furniture and fixtures
Property Plant And Equipment [Line Items]
Total	9,902	9,581
Construction in progress
Property Plant And Equipment [Line Items]
Total	$ 16,531	$ 11,220

[1] See Note 1 for a summary of adjustments.