CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (unaudited) - USD ($) shares in Thousands, $ in Thousands		3 Months Ended
		Mar. 31, 2019	Mar. 31, 2018
Income Statement [Abstract]
Revenue		$ 68,641	$ 58,491
Cost of revenue	[1],[2]	17,530	18,063
Gross profit		51,111	40,428
Operating expenses:
Research and development	[2]	20,806	17,940
Sales and marketing	[1],[2]	26,050	17,421
General and administrative	[2]	20,556	13,018
Restructuring		(66)	5
Total operating expenses		67,346	48,384
Loss from operations		(16,235)	(7,956)
Interest expense		3,659	7,094
Other non-operating income (expense), net		1,979	633
Loss before income taxes		(17,915)	(14,417)
Provision for (benefit from) income taxes		(138)	300
Net loss		$ (17,777)	$ (14,717)
Net loss per share, basic and diluted		$ (0.14)	$ (0.15)
Weighted-average shares used in computing basic and diluted net loss per share		126,786	101,212

[1] Includes amortization of acquisition intangible assets as follows: Three Months Ended March 31, (in thousands) 2019 2018 Cost of revenue $488 $488 Sales and marketing 537 604 Amortization of acquisition intangible assets $1,025 $1,092

[2] Includes stock-based compensation, net of amounts capitalized as follows: Three Months Ended March 31, (in thousands) 2019 2018 Cost of revenue $1,096 $658 Research and development 4,766 3,447 Sales and marketing 2,780 768 General and administrative 6,469 3,667 Stock-based compensation, net of amounts capitalized $15,111 $8,540