Description of Business and Summary of Significant Accounting Policies - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Disaggregation of Revenue [Line Items]
Revenue	$ 249,838	$ 218,876	$ 222,779
Hosted Services - Business
Disaggregation of Revenue [Line Items]
Revenue	197,474	178,686	183,551
Hosted Services - Consumer
Disaggregation of Revenue [Line Items]
Revenue	19,553	17,450	16,258
Professional Services
Disaggregation of Revenue [Line Items]
Revenue	$ 32,811	$ 22,740	$ 22,970

Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss).

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.1)
-URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688

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Balance Type:	credit
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