Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Statement [Abstract]
Net sales	$ 12,705	$ 18,107	$ 19,846
Cost of sales	10,731	14,695	15,025
Gross profit	1,974	3,412	4,821
Operating expenses:
Product development	1,284	2,597	2,940
Selling, general, and administrative	7,449	9,789	11,315
Loss on impairment	0	0	185
Restructuring	196	111	1,662
Total operating expenses	8,929	12,497	16,102
Loss from operations	(6,955)	(9,085)	(11,281)
Other expenses:
Interest expense	317	8	2
Other expenses	91	7	99
Loss from operations before income taxes	(7,363)	(9,100)	(11,382)
Provision for (benefit from) income taxes	10	11	(115)
Net loss	$ (7,373)	$ (9,111)	$ (11,267)
Denominator:
Net loss	$ (0.60)	$ (0.76)	$ (0.95)
Weighted average common shares outstanding:
Basic and diluted (in shares)	12,309	11,997	11,806