Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Statement [Abstract]
Net sales	$ 18,107	$ 19,846	$ 30,998
Cost of sales	14,695	15,025	23,321
Gross profit	3,412	4,821	7,677
Operating expenses:
Product development	2,597	2,940	3,537
Selling, general, and administrative	9,789	11,315	20,113
Loss on impairment	0	185	857
Restructuring	111	1,662	0
Total operating expenses	12,497	16,102	24,507
Loss from operations	(9,085)	(11,281)	(16,830)
Other expenses:
Interest expense	8	2	0
Other expenses	7	99	18
Loss from continuing operations before income taxes	(9,100)	(11,382)	(16,848)
Provision for (Benefit from) income taxes	11	(115)	27
Net loss from continuing operations	(9,111)	(11,267)	(16,875)
Discontinued operations:
Loss on sale of discontinued operations	0	0	(12)
Loss from discontinued operations before income taxes	0	0	(12)
Benefit from income taxes	0	0	0
Loss from discontinued operations	0	0	(12)
Net loss	$ (9,111)	$ (11,267)	$ (16,887)
Denominator:
Net loss from continuing operations - basic and diluted (in dollars per share)	$ (0.76)	$ (0.95)	$ (1.45)
Net loss from discontinued operations - basic and diluted (in dollars per share)	0.00	0.00	0.00
Net loss - basic and diluted (in dollars per share)	$ (0.76)	$ (0.95)	$ (1.45)
Weighted average common shares outstanding:
Basic and diluted (in shares)	11,997	11,806	11,673