Segment Information - Financial Information by Segment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Segment Reporting Information [Line Items]
Total revenue	$ 469,624	$ 366,620	$ 291,609
Cost of revenue	156,880	106,268	78,878
Sales and marketing	165,421	149,773	156,814
Amortization of purchased intangibles	2,045	1,639	1,794
Unallocated corporate expenses	238,544	198,391	141,155
Loss from operations	(93,266)	(89,451)	(87,032)
Corporate
Segment Reporting Information [Line Items]
Total revenue	0	0	0
Cost of revenue	0	0	0
Sales and marketing	0	0	0
Amortization of purchased intangibles	0	0	0
Unallocated corporate expenses	238,544	198,391	141,155
Loss from operations	(238,544)	(198,391)	(141,155)
Business | Operating Segments
Segment Reporting Information [Line Items]
Total revenue	431,929	336,856	267,129
Cost of revenue	149,983	99,394	74,460
Sales and marketing	139,866	128,752	140,880
Amortization of purchased intangibles	2,045	1,639	1,794
Unallocated corporate expenses	0	0	0
Loss from operations	140,035	107,071	49,995
Consumer | Operating Segments
Segment Reporting Information [Line Items]
Total revenue	37,695	29,764	24,480
Cost of revenue	6,897	6,874	4,418
Sales and marketing	25,555	21,021	15,934
Amortization of purchased intangibles	0	0	0
Unallocated corporate expenses	0	0	0
Loss from operations	5,243	1,869	4,128
Hosted Services - Business
Segment Reporting Information [Line Items]
Total revenue	364,231	286,588	225,705
Hosted Services - Business | Corporate
Segment Reporting Information [Line Items]
Total revenue	0	0	0
Hosted Services - Business | Business | Operating Segments
Segment Reporting Information [Line Items]
Total revenue	364,231	286,588	225,705
Hosted Services - Business | Consumer | Operating Segments
Segment Reporting Information [Line Items]
Total revenue	0	0	0
Hosted Services - Consumer
Segment Reporting Information [Line Items]
Total revenue	37,695	29,764	24,480
Hosted Services - Consumer | Corporate
Segment Reporting Information [Line Items]
Total revenue	0	0	0
Hosted Services - Consumer | Business | Operating Segments
Segment Reporting Information [Line Items]
Total revenue	0	0	0
Hosted Services - Consumer | Consumer | Operating Segments
Segment Reporting Information [Line Items]
Total revenue	37,695	29,764	24,480
Professional Services - Business
Segment Reporting Information [Line Items]
Total revenue	67,698	50,268	41,424
Professional Services - Business | Corporate
Segment Reporting Information [Line Items]
Total revenue	0	0	0
Professional Services - Business | Business | Operating Segments
Segment Reporting Information [Line Items]
Total revenue	67,698	50,268	41,424
Professional Services - Business | Consumer | Operating Segments
Segment Reporting Information [Line Items]
Total revenue	$ 0	$ 0	$ 0