Consolidated Statements of Operations - USD ($) shares in Thousands		12 Months Ended
		Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Net revenue		$ 326,801,000	$ 291,611,000	$ 201,597,000
Cost of net revenue	[1]	129,141,000	120,653,000	81,667,000
Gross profit		197,660,000	170,958,000	119,930,000
Operating expenses:
Product development	[1]	64,196,000	46,071,000	30,608,000
Sales, marketing and support	[1]	102,874,000	83,428,000	59,740,000
General and administrative	[1]	100,541,000	80,134,000	62,989,000
Total operating expenses	[1]	267,611,000	209,633,000	153,337,000
Loss from operations		(69,951,000)	(38,675,000)	(33,407,000)
Interest expense		(2,986,000)	(11,295,000)	(6,462,000)
Change in fair value of redeemable convertible preferred stock warrant liability		0	(9,591,000)	(2,200,000)
Loss on debt extinguishment		(1,742,000)	(178,000)	0
Other income (expense), net		5,727,000	(3,189,000)	3,509,000
Loss before income taxes		(68,952,000)	(62,928,000)	(38,560,000)
Income tax provision (benefit)		(192,000)	1,150,000	(13,000)
Net loss		$ (68,760,000)	$ (64,078,000)	$ (38,547,000)
Net loss per share, basic and diluted (in dollars per share)		$ (0.84)	$ (1.71)	$ (1.98)
Weighted-average number of shares outstanding used to compute net loss per share attributable to common stockholders, basic and diluted (in shares)		81,979	37,540	19,500
Cost of net revenue
Operating expenses:
Stock-based compensation expense		$ 1,397,000	$ 429,000	$ 200,000
Product development
Operating expenses:
Stock-based compensation expense		11,130,000	5,813,000	2,411,000
Sales, marketing and support
Operating expenses:
Stock-based compensation expense		5,471,000	3,570,000	2,364,000
General and administrative
Operating expenses:
Stock-based compensation expense		$ 19,596,000	$ 20,419,000	$ 5,883,000

[1] (1) Includes stock-based compensation as follows (in thousands):Year Ended December 31,201920182017Cost of net revenue$1,397  $429  $200  Product development11,130  5,813  2,411  Sales, marketing and support5,471  3,570  2,364  General and administrative19,596  20,419  5,883