Note 10 - Quarterly Results of Operations (Unaudited) - Results of Operations (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended																12 Months Ended
	Dec. 31, 2017		Sep. 30, 2017		Jun. 30, 2017		Mar. 31, 2017		Dec. 31, 2016		Sep. 30, 2016		Jun. 30, 2016		Mar. 31, 2016		Dec. 31, 2017	Dec. 31, 2016
Net sales	$ 11,946		$ 10,427		$ 11,615		$ 11,190		$ 9,802		$ 11,036		$ 12,053		$ 11,683		$ 45,178	$ 44,574
Gross profit	(2,466)		2,333		2,732		2,237		1,976		1,835		2,062		2,541		4,836	8,414
Net (loss) income	$ (7,002)	[1]	$ (305)		$ 14		$ (416)		$ (301)	[1]	$ (2,080)		$ (1,392)		$ (1,485)		$ (7,709)	$ (5,258)
Basic (in dollars per share)	$ (0.49)	[2]	$ (0.02)	[2]		[2]	$ (0.03)	[2]	$ (0.02)	[2]	$ (0.15)	[2]	$ (0.10)	[2]	$ (0.10)	[2]	$ (0.54)	$ (0.37)
Diluted (in dollars per share)	$ (0.49)	[2]	$ (0.02)	[2]		[2]	$ (0.03)	[2]	$ (0.02)	[2]	$ (0.15)	[2]	$ (0.10)	[2]	$ (0.10)	[2]	$ (0.54)	$ (0.37)

[1] Includes proceeds received from the Continued Dumping and Subsidy Offset Act, net of taxes, of $0.4 million in the fourth quarter of 2017 and $1.1 million in fourth quarter of 2016.

[2] The sum of individual quarterly net loss per share may not agree to the total for the year due to each period's computation being based on the weighted average number of common shares outstanding during each period.