Description of Business and Basis of Presentation - Summary of Unaudited Consolidated Statement of Cash Flows Reflecting Adoption of Topic 606 (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Operating activities:
Net loss	$ (35,878)	$ (33,340)
Accounts receivable, net	(14,011)	(17,270)
Prepaid expenses and other assets	(168)	(1,868)
Deferred commissions	(1,172)	(3,833)
Deferred revenue	37,011	35,692
Net cash used in operating activities	$ 20,270	3,922
As Previously Reported | Adoption of New Standard
Operating activities:
Net loss		(38,100)
Accounts receivable, net		(17,620)
Prepaid expenses and other assets		(2,229)
Deferred revenue		37,331
Net cash used in operating activities		3,922
Adjustments | Adoption of New Standard
Operating activities:
Net loss		4,760
Accounts receivable, net		350
Prepaid expenses and other assets		361
Deferred commissions		(3,833)
Deferred revenue		$ (1,639)