CONDENSED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
CONDENSED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS
Revenue	$ 10,938	$ 6,042	$ 20,980	$ 11,339
Cost of goods sold	2,102	1,376	4,396	2,572
Gross profit	8,836	4,666	16,584	8,767
Operating expenses:
Selling and marketing	10,733	6,506	20,601	12,251
Research and development	1,735	1,743	3,465	3,336
General and administrative	2,005	801	3,350	1,688
Total operating expenses	14,473	9,050	27,416	17,275
Operating loss	(5,637)	(4,384)	(10,832)	(8,508)
Other expense (income):
Interest income	(348)	(46)	(408)	(64)
Interest expense	550	422	1,935	796
Other expense (income), net	17	(4)	(2)	(3)
Total other expense	219	372	1,525	729
Loss before income taxes	(5,856)	(4,756)	(12,357)	(9,237)
Income taxes			0
Net loss	(5,856)	(4,756)	(12,357)	(9,237)
Total comprehensive loss	$ (5,856)	$ (4,756)	$ (12,357)	$ (9,237)
Net loss per share, basic and diluted	$ (0.43)	$ (4.14)	$ (1.66)	$ (8.04)
Weighted average common shares used to compute net loss per share, basic and diluted	13,543,558	1,150,092	7,448,955	1,149,333