Segment Information (Summary of Financial Information by Segment) (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Revenue:
Revenue	$ 61,660	$ 54,074	$ 119,901	$ 104,993
Cost of revenue	16,036	15,134	29,990	28,915
Sales and marketing	25,392	23,392	49,523	45,092
Amortization of purchased intangibles	424	470	848	942
Unallocated corporate expenses	27,624	21,839	51,177	41,730
Loss from operations	(7,816)	(6,761)	(11,637)	(11,686)
Corporate
Revenue:
Unallocated corporate expenses	27,624	21,839	51,177	41,730
Loss from operations	(27,624)	(21,839)	(51,177)	(41,730)
Business \| Operating Segments
Revenue:
Revenue	56,708	49,614	110,269	96,363
Cost of revenue	15,086	14,206	28,004	27,112
Sales and marketing	23,339	21,242	45,062	40,785
Amortization of purchased intangibles	424	470	848	942
Loss from operations	17,859	13,696	36,355	27,524
Consumer \| Operating Segments
Revenue:
Revenue	4,952	4,460	9,632	8,630
Cost of revenue	950	928	1,986	1,803
Sales and marketing	2,053	2,150	4,461	4,307
Loss from operations	1,949	1,382	3,185	2,520
Hosted Services - Business
Revenue:
Revenue	48,331	43,927	95,759	85,420
Hosted Services - Business \| Business \| Operating Segments
Revenue:
Revenue	48,331	43,927	95,759	85,420
Hosted Services - Consumer
Revenue:
Revenue	4,952	4,460	9,632	8,630
Hosted Services - Consumer \| Consumer \| Operating Segments
Revenue:
Revenue	4,952	4,460	9,632	8,630
Professional Services
Revenue:
Revenue	8,377	5,687	14,510	10,943
Professional Services \| Business \| Operating Segments
Revenue:
Revenue	$ 8,377	$ 5,687	$ 14,510	$ 10,943

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The aggregate expense charged against earnings to allocate the cost of intangible assets (nonphysical assets not used in production) in a systematic and rational manner to the periods expected to benefit from such assets. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6388964&loc=d3e16225-109274

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3602-108585

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
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-Section 50
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The aggregate cost of goods produced and sold and services rendered during the reporting period.

+ References

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 210.5-03.2)
-URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688

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+ References

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+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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The aggregate total amount of expenses directly related to the marketing or selling of products or services.

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