Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Statement [Abstract]
Net sales	$ 19,846	$ 30,998	$ 64,403
Cost of sales	15,025	23,321	35,111
Gross profit	4,821	7,677	29,292
Operating expenses:
Product development	2,940	3,537	2,810
Selling, general, and administrative	11,315	20,113	16,830
Loss on impairment	185	857	0
Restructuring	1,662	0	0
Total operating expenses	16,102	24,507	19,640
(Loss) income from operations	(11,281)	(16,830)	9,652
Other expense (income):
Interest expense	2	0	85
Other expenses (income)	99	18	(53)
(Loss) income from continuing operations before income taxes	(11,382)	(16,848)	9,620
(Benefit from) provision for income taxes	(115)	27	149
Net (loss) income from continuing operations	(11,267)	(16,875)	9,471
Discontinued operations:
Loss from discontinued operations	0	0	(167)
Loss on sale of discontinued operations	0	(12)	(534)
(Loss) income from discontinued operations before income taxes	0	(12)	(701)
Benefit from income taxes	0	0	(10)
(Loss) from discontinued operations	0	(12)	(691)
Net (loss) income	$ (11,267)	$ (16,887)	$ 8,780
Net (loss) income per share - basic:
Net income (loss) from continuing operations (in dollars per share)	$ (0.95)	$ (1.45)	$ 0.91
Net (loss) income from discontinued operations (in dollars per share)	0.00	0.00	(0.07)
Net income (loss) (in dollars per share)	(0.95)	(1.45)	0.84
Net (loss) income per share - diluted:
Net income (loss) from continuing operations (in dollars per share)	(0.95)	(1.45)	0.88
Net (loss) income from discontinued operations (in dollars per share)	0.00	0.00	(0.06)
Net income (loss) (in dollars per share)	$ (0.95)	$ (1.45)	$ 0.82
Weighted average common shares outstanding:
Basic (in shares)	11,806	11,673	10,413
Diluted (in shares)	11,806	11,673	10,752