Segment Information (Summary of Financial Information by Segment) (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Revenue:
Hosted services – Business		$ 46,378	$ 44,553	$ 131,798	$ 137,240
Hosted services – Consumer		4,355	4,044	12,985	12,048
Professional services		5,760	5,921	16,703	17,374
Total revenue		56,493	54,518	161,486	166,662
Cost of revenue	[1],[2],[3]	14,541	14,837	43,456	48,210
Sales and marketing	[2],[3]	21,603	22,067	66,695	67,831
Amortization of purchased intangibles		470	1,013	1,412	2,954
Unallocated corporate expenses		20,124	19,180	61,854	58,802
Loss from operations		(245)	(2,579)	(11,931)	(11,135)
Corporate [Member]
Revenue:
Unallocated corporate expenses		20,124	19,180	61,854	58,802
Loss from operations		(20,124)	(19,180)	(61,854)	(58,802)
Business [Member] | Operating Segments [Member]
Revenue:
Hosted services – Business		46,378	44,553	131,798	137,240
Professional services		5,760	5,921	16,703	17,374
Total revenue		52,138	50,474	148,501	154,614
Cost of revenue		13,681	14,215	40,794	46,145
Sales and marketing		19,554	20,278	60,338	62,606
Amortization of purchased intangibles		470	1,013	1,412	2,954
Loss from operations		18,433	14,968	45,957	42,909
Consumer [Member] | Operating Segments [Member]
Revenue:
Hosted services – Consumer		4,355	4,044	12,985	12,048
Total revenue		4,355	4,044	12,985	12,048
Cost of revenue		860	622	2,662	2,065
Sales and marketing		2,049	1,789	6,357	5,225
Loss from operations		$ 1,446	$ 1,633	$ 3,966	$ 4,758

[1] Amounts include amortization expense as follows: Cost of revenue $639 thousand and $697 thousand thousand for the three months ended September 30, 2017 and 2016, respectively.Amounts include amortization expense as follows: Cost of revenue $2,556 thousand and $2,091 thousand thousand for the three months ended September 30, 2017 and 2016, respectively.

[2] Amounts include depreciation expense as follows: Cost of revenue $1,715 thousand and $1,756 thousand for the three months ended September 30, 2017 and 2016, respectively, Sales and marketing $417 thousand and $212 thousand for the three months ended September 30, 2017 and 2016, respectively, General and administrative $321 thousand and $435 thousand for the three months ended September 30, 2017 and 2016, respectively, and Product development $726 thousand and $247 thousand for the three months ended September 30, 2017 and 2016, respectively. Amounts include depreciation expense as follows: Cost of revenue $5,350 thousand and $$6,469 thousand for the three months ended September 30, 2017 and 2016, respectively, Sales and marketing $1,206 thousand and $1,012 thousand for the three months ended September 30, 2017 and 2016, respectively, General and administrative $911 thousand and $1,215 thousand for the three months ended September 30, 2017 and 2016, respectively, and Product development $1,550 thousand and $749 thousand for the three months ended September 30, 2017 and 2016, respectively.

[3] Amounts include stock compensation expense as follows: Cost of revenue $108 thousand and $121 thousand for the three months ended September 30, 2017 and 2016, respectively, Sales and marketing $576 thousand and $502 thousand for the three months ended September 30, 2017 and 2016, respectively, General and administrative $622 thousand and $759 thousand for the three months ended September 30, 2017 and 2016, respectively and Product development $537 thousand and $873 thousand for the three months ended September 30, 2017 and 2016, respectively. Amounts include stock compensation expense as follows: Cost of revenue $301 thousand and $342 thousand for the nine months ended September 30, 2017 and 2016, respectively, Sales and marketing $1,984 thousand and $1,936 thousand for the nine months ended September 30, 2017 and 2016, respectively, General and administrative $2,058 thousand and $2,552 thousand for the nine months ended September 30, 2017 and 2016, respectively and Product development $1,760 thousand and $2,770 thousand for the nine months ended September 30, 2017 and 2016, respectively.