Consolidated Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Statement Of Income And Comprehensive Income [Abstract]
Revenue	$ 271,141	$ 200,882	$ 147,094
Cost of revenue	83,028	63,535	46,810
Gross profit	188,113	137,347	100,284
Operating expenses:
Sales and marketing	123,330	87,731	69,608
Research and development	62,512	50,024	41,305
General and administrative	74,485	46,820	31,462
Total operating expenses	260,327	184,575	142,375
Operating loss	(72,214)	(47,228)	(42,091)
Other expense, net:
Interest income	2,007	4,499	1,842
Interest expense	(24,089)	(7,478)	(6,346)
Loss on extinguishment of convertible notes	(446)	(1,406)
Other expenses, net	(921)	(212)	(124)
Total other expense, net	(23,449)	(4,597)	(4,628)
Loss before income taxes	(95,663)	(51,825)	(46,719)
Benefit from (provision for) income taxes	2,267	(425)	(796)
Net loss	$ (93,396)	$ (52,250)	$ (47,515)
Net loss per share attributable to common stockholders:
Basic	$ (2.70)	$ (1.58)	$ (1.63)
Diluted	$ (2.70)	$ (1.58)	$ (1.63)
Weighted-average common shares outstanding:
Basic	34,581,144	33,161,656	29,107,267
Diluted	34,581,144	33,161,656	29,107,267
Other comprehensive income (loss):
Foreign currency translation adjustment	$ 8,557	$ (679)	$ (5,288)
Total other comprehensive income (loss)	8,557	(679)	(5,288)
Total comprehensive loss	$ (84,839)	$ (52,929)	$ (52,803)