Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Revenue	$ 779,796	$ 486,920	$ 370,036
Cost of revenue	635,693	367,496	258,216
Gross profit	144,103	119,424	111,820
Operating expenses
Technology and development	69,765	53,797	42,532
Marketing	76,710	44,061	32,251
General and administrative	76,874	65,500	53,009
Total operating expenses	223,349	163,358	127,792
Loss from operations	(79,246)	(43,934)	(15,972)
Interest income	7,146	5,416	882
Interest expense	(8,928)	(3,681)	0
Other income, net	223	221	88
Net loss	(80,805)	(41,978)	(15,002)
Accretion of redeemable convertible preferred stock	0	0	(175,915)
Net loss attributable to common stock—basic	(80,805)	(41,978)	(190,917)
Net loss attributable to common stock—diluted	$ (80,805)	$ (41,978)	$ (190,917)
Net loss per share attributable to common stock—basic and diluted (in dollars per share)	$ (0.88)	$ (0.49)	$ (4.47)
Weighted average shares of common stock—basic and diluted (in shares)	91,583,533	85,669,039	42,722,114
Net loss	$ (80,805)	$ (41,978)	$ (190,917)
Other comprehensive income:
Foreign currency translation adjustments	33	0	0
Unrealized gain on available-for-sale securities	9	0	0
Total comprehensive loss	(80,763)	(41,978)	(190,917)
Service
Revenue	539,288	441,927	359,545
Cost of revenue	390,504	320,883	247,832
Product
Revenue	240,508	44,993	10,491
Cost of revenue	$ 245,189	$ 46,613	$ 10,384