Deferred Solution and Other Costs (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Deferred solution costs	$ 6,505	$ 6,295
Deferred commissions	2,741	2,544
Deferred solution and other costs, current portion	9,246	8,839
Deferred solution costs	5,291	4,741
Deferred commissions	7,682	6,384
Deferred solution and other costs, net of current portion	$ 12,973	$ 11,125