Condensed Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Revenue	$ 104,935	$ 77,714	$ 164,802	$ 119,349
Cost of revenue	67,975	50,303	121,467	88,808
Gross profit	36,960	27,411	43,335	30,541
Operating expenses:
Technology and development	10,090	8,060	19,762	15,958
Marketing	10,132	8,486	20,591	17,697
General and administrative	12,466	9,526	26,833	19,912
Total operating expenses	32,688	26,072	67,186	53,567
Income (loss) from operations	4,272	1,339	(23,851)	(23,026)
Interest income	32	49	76	96
Other income, net	0	0	13	37
Total interest income and other income, net	32	49	89	133
Net income (loss)	4,304	1,388	(23,762)	(22,893)
Accretion of redeemable convertible preferred stock	(110,921)	65,082	(135,690)	59,869
Undistributed earnings attributable to participating securities	0	(52,805)	0	(29,397)
Net income (loss) attributable to common stock—basic	(106,617)	13,665	(159,452)	7,579
Net income (loss) attributable to common stock - diluted	$ (106,617)	$ 1,388	$ (159,452)	$ (22,893)
Net income (loss) per share attributable to common stock - basic (in dollars per share)	$ (7.15)	$ 0.95	$ (10.74)	$ 0.53
Net income (loss) per share attributable to common stock - diluted (in dollars per share)	$ (7.15)	$ 0.02	$ (10.74)	$ (0.33)
Weighted average shares used to compute net income (loss) per share attributable to common stock - basic	14,913,234	14,340,333	14,840,759	14,288,550
Weighted average shares used to compute net income (loss) per share attributable to common stock - diluted	14,913,234	74,080,026	14,840,759	69,710,552
Pro Forma
Operating expenses:
Pro forma net income (loss) per share attributable to common stock—basic and diluted (in dollars per share)	$ 0.06		$ (0.34)
Pro forma weighted-average shares used to compute net income (loss) per share attributable to common stock—basic and diluted	70,335,236		70,262,761