Deferred Revenue - Components of Deferred Revenue (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Deferred Revenue Arrangement [Line Items]
Total current	$ 24,002	$ 20,708
Total noncurrent	7,079	6,652
Total	31,081	27,360
Subscription [Member]
Deferred Revenue Arrangement [Line Items]
Total current	17,342	14,826
Total noncurrent	1,960	1,950
Professional Services - Implementation [Member]
Deferred Revenue Arrangement [Line Items]
Total current	3,457	2,974
Total noncurrent	4,612	4,327
Professional Services - Communications [Member]
Deferred Revenue Arrangement [Line Items]
Total current	3,203	2,908
Total noncurrent	$ 507	$ 375