Consolidated Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Statement Of Income And Comprehensive Income [Abstract]
Revenue	$ 200,882	$ 147,094	$ 104,352
Cost of revenue	63,535	46,810	31,503
Gross profit	137,347	100,284	72,849
Operating expenses:
Sales and marketing	87,731	69,608	46,998
Research and development	50,024	41,305	22,241
General and administrative	46,820	31,462	22,895
Total operating expenses	184,575	142,375	92,134
Operating loss	(47,228)	(42,091)	(19,285)
Other income (expense), net:
Interest income	4,499	1,842	475
Interest expense	(7,478)	(6,346)	(691)
Loss on extinguishment of convertible notes	(1,406)
Other expenses, net	(212)	(124)	(86)
Total other income (expense), net	(4,597)	(4,628)	(302)
Loss before income taxes	(51,825)	(46,719)	(19,587)
Provision for income taxes	(425)	(796)	(47)
Net loss	$ (52,250)	$ (47,515)	$ (19,634)
Net loss per share attributable to common stockholders:
Basic	$ (1.58)	$ (1.63)	$ (0.70)
Diluted	$ (1.58)	$ (1.63)	$ (0.70)
Weighted-average common shares outstanding:
Basic	33,161,656	29,107,267	27,862,375
Diluted	33,161,656	29,107,267	27,862,375
Other comprehensive income (loss):
Foreign currency translation adjustment, net of taxes	$ (679)	$ (5,288)	$ 523
Total other comprehensive income (loss)	(679)	(5,288)	523
Total comprehensive loss	$ (52,929)	$ (52,803)	$ (19,111)