Description of Operations and Summary of Significant Accounting Policies - Summary of Select Unaudited Condensed Consolidated Statement of Cash Flows Reflect Adoption of Accounting Standards (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Cash flows from operating activities
Net loss	$ (8,099)	$ (7,139)	[1]
Adjustments to reconcile net loss to net cash provided by operating activities:
Amortization of deferred costs	3,936	3,268	[1]
Foreign exchange gain	(114)	(174)	[1]
Change in operating assets and liabilities
Deferred costs	(2,908)	(2,672)	[1]
Net cash provided by operating activities	$ 9,776	11,918	[1]
Foreign currency effect on cash, cash equivalents and restricted cash		(135)
Net decrease in cash, cash equivalents and restricted cash		(4,103)
Cash, cash equivalents and restricted cash
End of period		37,904
ASU 2014-09 | As Previously Reported
Cash flows from operating activities
Net loss		(6,547)
Adjustments to reconcile net loss to net cash provided by operating activities:
Foreign exchange gain		(175)
Change in operating assets and liabilities
Net cash provided by operating activities		11,913
Foreign currency effect on cash, cash equivalents and restricted cash		(130)
Net decrease in cash, cash equivalents and restricted cash		(4,103)
Cash, cash equivalents and restricted cash
End of period		37,904
ASU 2014-09 | Adjustments
Cash flows from operating activities
Net loss		(592)
Adjustments to reconcile net loss to net cash provided by operating activities:
Amortization of deferred costs		3,268
Foreign exchange gain		1
Change in operating assets and liabilities
Deferred costs		(2,672)
Net cash provided by operating activities		5
Foreign currency effect on cash, cash equivalents and restricted cash		$ (5)

[1] See Note 1 for a summary of adjustments