CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (unaudited) - USD ($) shares in Thousands, $ in Thousands		3 Months Ended
		Mar. 31, 2021	Mar. 31, 2020
Income Statement [Abstract]
Revenue		$ 102,298	$ 88,265
Cost of revenue	[1],[2]	20,772	19,944
Gross profit		81,526	68,321
Operating expenses:
Research and development	[1]	32,983	26,557
Sales and marketing	[1],[2]	52,036	42,091
General and administrative	[1]	23,322	21,932
Total operating expenses		108,341	90,580
Loss from operations		(26,815)	(22,259)
Interest expense		2,299	3,086
Other non-operating (income) expense, net		315	(1,236)
Loss before income taxes		(29,429)	(24,109)
Provision for income taxes		218	141
Net loss		$ (29,647)	$ (24,250)
Net loss per share, basic and diluted		$ (0.20)	$ (0.18)
Weighted-average shares used in computing basic and diluted net loss per share		144,692	136,911

[1] ⁽¹⁾       Includes stock-based compensation, net of amounts capitalized as follows:       Three Months Ended March 31,   (in thousands)   2021   2020   Cost of revenue   $ 1,482   $ 960   Research and development     9,497     6,457   Sales and marketing     5,778     4,343   General and administrative     6,842     5,742   Stock-based compensation, net of amounts capitalized   $ 23,599   $ 17,502  

[2] ⁽²⁾      Includes amortization of acquisition intangible assets as follows:       Three Months Ended March 31,   (in thousands)   2021   2020   Cost of revenue   $ 1,490   $ 2,010   Sales and marketing     1,133     1,358   Amortization of acquisition intangible assets   $ 2,623   $ 3,368