Note 5 - Inventory - Summary of Inventory (Details) - USD ($)	Mar. 31, 2018	Jan. 01, 2018	Dec. 31, 2017
Raw materials and supplies	$ 265,000		$ 298,000
Finished goods	352,000		346,000
Less allowance for excess and obsolete inventory and lower of cost or estimated net realizable value adjustments	(138,000)		(140,000)
Total inventory, net	$ 479,000	$ 479	$ 504,000