CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands		12 Months Ended
		Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Income Statement [Abstract]
Revenue		$ 443,786	$ 375,610	$ 307,421
Cost of revenue	[1],[2],[3]	86,421	83,917	76,524
Gross profit		357,365	291,693	230,897
Operating expenses:
Research and development	[2],[3]	139,262	112,989	90,545
Sales and marketing	[1],[2],[3]	224,008	172,376	123,573
General and administrative	[2],[3]	106,667	87,909	83,288
Restructuring		0	0	(66)
Total operating expenses		469,937	373,274	297,340
Loss from operations		(112,572)	(81,581)	(66,443)
Interest expense		9,261	10,257	14,157
Other non-operating (income) expense, net		934	(1,436)	(3,962)
Loss before income taxes		(122,767)	(90,402)	(76,638)
Provision for (benefit from) income taxes		482	1,179	(2,779)
Net loss		$ (123,249)	$ (91,581)	$ (73,859)
Net loss per share, basic and diluted		$ (0.84)	$ (0.65)	$ (0.56)
Weighted-average shares used in computing basic and diluted net loss per share		147,045	139,887	131,568

[1] Includes amortization of acquisition intangible assets as follows:

[2] Includes stock-based compensation, net of amounts capitalized as follows:

[3] Includes transaction expenses associated with the proposed merger with Zendesk. See Note 1 for additional information.