Summary Of Operations And Significant Accounting Policies (Summary Of Financial Information By Segment) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Segment Reporting Information [Line Items]
Hosted services - Business									$ 132,310	$ 111,934	$ 91,262
Hosted services - Consumer									15,111	14,522	14,195
Professional services									9,988	6,633	4,405
Total revenue	42,475	39,670	38,505	36,759	36,509	34,347	31,851	30,382	157,409	133,089	109,862
Cost of revenue	10,128	9,036	8,492	7,923	8,047	8,368	8,685	8,095	35,579	33,195	29,640
Sales and marketing	12,795	12,713	13,017	11,089	10,738	9,907	9,379	8,860	49,614	38,884	32,835
Amortization of intangibles	119	11	11	77	76	11	11	11	218	109	259
Unallocated corporate expenses									61,657	41,266	32,788
Income from operations	2,440	2,589	424	4,888	6,076	5,106	3,374	5,079	10,341	19,635	14,340
Corporate [Member]
Segment Reporting Information [Line Items]
Unallocated corporate expenses									61,657	41,266	32,788
Income from operations									(61,657)	(41,266)	(32,788)
Business [Member]
Segment Reporting Information [Line Items]
Hosted services - Business									132,310	111,934	91,262
Professional services									9,988	6,633	4,405
Total revenue									142,298	118,567	95,667
Cost of revenue									33,450	29,793	25,863
Sales and marketing									44,087	32,690	26,184
Amortization of intangibles									218	109	43
Income from operations									64,543	55,975	43,577
Consumer [Member]
Segment Reporting Information [Line Items]
Hosted services - Consumer									15,111	14,522	14,195
Total revenue									15,111	14,522	14,195
Cost of revenue									2,129	3,402	3,777
Sales and marketing									5,527	6,194	6,651
Amortization of intangibles											216
Income from operations									$ 7,455	$ 4,926	$ 3,551