Accrued Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Payables and Accruals [Abstract]
Accrued data center equipment and software purchases	$ 4,410	$ 232
Accrued transaction processing fees	1,687	1,790
Accrued professional services	1,419	1,518
Acquisition hold back	150	2,500
Deferred rent	1,197	1,066
Other	1,699	1,716
Total accrued liabilities	$ 10,562	$ 8,822