Deferred Revenue - Components of Deferred Revenue (Details) - USD ($)
$ in Thousands
Dec. 31, 2015
Dec. 31, 2014
Deferred Revenue Arrangement [Line Items]    
Total current $ 26,590 $ 20,708
Total noncurrent 7,522 6,652
Total 34,112 27,360
Subscription [Member]    
Deferred Revenue Arrangement [Line Items]    
Total current 18,029 14,826
Total noncurrent 1,163 1,950
Professional Services - Implementation [Member]    
Deferred Revenue Arrangement [Line Items]    
Total current 5,254 2,974
Total noncurrent 5,367 4,327
Professional Services - Communications [Member]    
Deferred Revenue Arrangement [Line Items]    
Total current 3,307 2,908
Total noncurrent $ 992 $ 375