CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Income Statement [Abstract]
Revenue	$ 67,301
Revenue		$ 55,380
Cost of goods sold	6,790	4,833
Gross profit	60,511	50,547
Operating expenses:
Sales and marketing	68,251	44,497
Research and development	7,279	5,376
General and administrative	20,984	12,639
Total operating expenses	96,514	62,512
Loss from operations	(36,003)	(11,965)
Interest and other income (expense), net:
Interest income	2,551	769
Interest expense	(4,949)	(5,108)
Other expense, net	(2)	(1,149)
Net loss	(38,403)	(17,453)
Other comprehensive income (loss):
Unrealized gain of marketable securities	44	10
Changes in foreign currency translation	(19)	27
Comprehensive loss	$ (38,378)	$ (17,416)
Net loss per share, basic and diluted (in dollars per share)	$ (1.55)	$ (2.20)
Weighted-average number of common shares used to compute basic and diluted net loss per share (in shares)	24,705,980	7,950,284