CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (unaudited) - USD ($) shares in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Income Statement [Abstract]
Revenue		$ 75,139,000	$ 62,696,000	$ 143,780,000	$ 121,187,000
Cost of revenue	[1],[2]	19,047,000	17,691,000	36,577,000	35,754,000
Gross profit		56,092,000	45,005,000	107,203,000	85,433,000
Operating expenses:
Research and development	[2]	22,407,000	16,292,000	43,213,000	34,232,000
Sales and marketing	[1],[2]	29,689,000	19,879,000	55,739,000	37,300,000
General and administrative	[2]	19,746,000	13,400,000	40,302,000	26,418,000
Restructuring		0	28,000	(66,000)	33,000
Total operating expenses		71,842,000	49,599,000	139,188,000	97,983,000
Loss from operations		(15,750,000)	(4,594,000)	(31,985,000)	(12,550,000)
Interest expense		3,647,000	7,591,000	7,306,000	14,685,000
Other non-operating income (expense), net		575,000	(282,000)	2,554,000	351,000
Loss before income taxes		(18,822,000)	(12,467,000)	(36,737,000)	(26,884,000)
Provision for (benefit from) income taxes		(344,000)	(4,000)	(482,000)	296,000
Net loss		$ (18,478,000)	$ (12,463,000)	$ (36,255,000)	$ (27,180,000)
Net loss per share, basic and diluted		$ (0.14)	$ (0.12)	$ (0.28)	$ (0.27)
Weighted-average shares used in computing basic and diluted net loss per share		131,099	101,623	128,943	101,419

[1] Includes amortization of acquisition intangible assets as follows: Three Months Ended June 30, Six Months Ended June 30, (in thousands) 2019 2018 2019 2018 Cost of revenue $1,403 $488 $1,891 $976 Sales and marketing 766 604 1,303 1,208 Amortization of acquisition intangible assets $2,169 $1,092 $3,194 $2,184

[2] Includes stock-based compensation, net of amounts capitalized as follows: Three Months Ended June 30, Six Months Ended June 30, (in thousands) 2019 2018 2019 2018 Cost of revenue $991 $646 $2,087 $1,304 Research and development 5,629 2,966 10,395 6,413 Sales and marketing 3,016 1,147 5,796 1,915 General and administrative 5,518 3,993 11,987 7,660 Stock-based compensation, net of amounts capitalized $15,154 $8,752 $30,265 $17,292