Deferred Revenue and Performance Obligations - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Deferred Revenue Arrangement [Line Items]
Percentage of revenue expected to be recognized from remaining performance obligation			90.00%
Revenue, remaining performance obligation, expected timing of satisfaction, period	24 months		24 months
Subscription
Deferred Revenue Arrangement [Line Items]
Recognition of deferred revenue	$ 46.2	$ 32.6	$ 96.8	$ 81.1
Revenue expected to be recognized from remaining performance obligation	223.8		223.8
Professional Services
Deferred Revenue Arrangement [Line Items]
Recognition of deferred revenue	3.2	$ 2.0	5.9	$ 4.3
Revenue expected to be recognized from remaining performance obligation	$ 17.2		$ 17.2