Condensed Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Statement of Comprehensive Income [Abstract]
Net revenue	$ 35,243	$ 1,309	$ 76,752	$ 3,874
Cost of goods sold	13,434	632	31,792	1,952
Gross profit	21,809	677	44,960	1,922
Operating Expenses
Research and development	7,748	4,855	21,030	13,948
General and administrative	5,773	5,162	18,963	13,539
Sales and marketing	17,057	15,707	47,846	32,371
Total operating expenses	30,578	25,724	87,839	59,858
Loss from operations	(8,769)	(25,047)	(42,879)	(57,936)
Other Income (Expense)
Interest income	35	627	742	2,500
Interest and other expense	(434)	(586)	(1,429)	(1,747)
Other income (expense), net	(399)	41	(687)	753
Loss before income tax expense	(9,168)	(25,006)	(43,566)	(57,183)
Income tax expense	0	0	1	1
Net loss	(9,168)	(25,006)	(43,567)	(57,184)
Foreign currency translation adjustment	99	(112)	(186)	(165)
Comprehensive loss	$ (9,069)	$ (25,118)	$ (43,753)	$ (57,349)
Net loss per share, basic and diluted (USD per share)	$ (0.24)	$ (0.89)	$ (1.20)	$ (2.05)
Weighted-average shares used to compute basic and diluted net loss per share (shares)	38,830,924	28,098,564	36,312,984	27,958,376