Condensed Consolidated Statements of Operations and Comprehensive Loss - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Condensed Consolidated Statements of Operations and Comprehensive Loss [Abstract]
Net sales	$ 2,508	$ 1,863	$ 4,426	$ 3,493
Cost of goods sold	997	664	1,949	1,460
Gross profit	1,511	1,199	2,477	2,033
Operating expenses:
Selling, general and administrative	5,063	4,234	10,300	8,770
Research and development	1,174	885	2,121	1,749
Total operating expenses	6,237	5,119	12,421	10,519
Loss from operations	(4,726)	(3,920)	(9,944)	(8,486)
Other income (expense), net	(2)	0	(3)	0
Loss before income taxes	(4,728)	(3,920)	(9,947)	(8,486)
Income tax expense	(3)	(2)	(5)	(4)
Net loss	$ (4,731)	$ (3,922)	$ (9,952)	$ (8,490)
Basic loss per share (in dollars per share)	$ (0.72)	$ (3.10)	$ (2.04)	$ (11.31)
Diluted loss per share (in dollars per share)	$ (0.72)	$ (3.10)	$ (2.04)	$ (11.31)
Weighted average shares outstanding - basic (in shares)	6,532	1,264	4,887	906
Weighted average shares outstanding - diluted (in shares)	6,532	1,264	4,887	906
Other comprehensive loss:
Foreign currency translation adjustments	$ 0	$ (2)	$ (3)	$ (5)
Total comprehensive loss	$ (4,731)	$ (3,924)	$ (9,955)	$ (8,495)