Revenue - Narrative (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Dec. 31, 2017	Jan. 01, 2016
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Retained earnings/(accumulated deficit)	$ 5,076	$ (6,819)
Amortization period for capitalized costs to obtain contract	2 years
Capitalized costs to obtain contract with customer	$ 1,000	500
Deferred revenue	15,087	13,891
Contract with Customer, Liability, Revenue Recognized	$ 12,700
Accounting Standards Update 2014-09
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Retained earnings/(accumulated deficit)		(6,819)
Deferred revenue		$ 13,891
Accounting Standards Update 2014-09 | Difference between Revenue Guidance in Effect before and after Topic 606
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Retained earnings/(accumulated deficit)			$ 600