Note 12 - Unaudited Quarterly Financial Data - Selected Quarterly Data (Details) - USD ($)	3 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014
Net sales	$ 1,677,000	$ 2,155,000	$ 5,443,000	$ 4,605,000	$ 3,411,000	$ 5,261,000	$ 6,178,000	$ 7,073,000
Gross margin	446,000	638,000	1,305,000	1,021,000	697,000	1,064,000	1,150,000	1,341,000
Net earnings (loss) from continuing operations	(435,000)	(334,000)	177,000	6,000	(63,000)	(2,319,000)	(53,000)	(11,000)
Discontinued operations, net of $0 income taxes	0	0	14,000	73,000	$ 173,000	(3,595,000)	279,000	82,000
Net earnings (loss)	$ (435,000)	$ (334,000)	$ 191,000	$ 79,000		$ (5,914,000)	$ 226,000	$ 71,000
Continuing operations (in dollars per share)	$ (0.04)	$ (0.03)	$ 0.02	$ 0	$ 0	$ (0.20)	$ 0	$ 0
Discontinued operations (in dollars per share)	0	0	0	0.01	0.01	(0.30)	0.02	0.01
Net income (loss) per share (in dollars per share)	(0.04)	(0.03)	0.02	0.01	0.01	(0.50)	0.02	0.01
Continuing operations (in dollars per share)	(0.04)	(0.03)	0.02	0	0	(0.20)	0	0
Discontinued operations (in dollars per share)	0	0	0	0.01	0.01	(0.30)	0.02	0.01
Net earnings (loss) per share (in dollars per share)	$ (0.04)	$ (0.03)	$ 0.02	$ 0.01	$ 0.01	$ (0.50)	$ 0.02	$ 0.01
Net loss from continuing operations	$ (435,000)	$ (334,000)	$ 177,000	$ 6,000	$ (63,000)	$ (2,319,000)	$ (53,000)	$ (11,000)