Note 11 - Deferred Income Tax Assets (Details) - USD ($)	Dec. 31, 2015	Dec. 31, 2014
Foreign tax credits	$ 66,000	$ 16,000
Inventory reserve	107,000	158,000
Accrued expenses and inventory	311,000	312,000
Current deferred income tax assets, net	484,000	486,000
Non-current deferred income taxes:
Property and equipment	(681,000)	(755,000)
Intangible assets	(3,000)	(3,000)
Marketable securities	78,000	758,000
Marketable securities	(78,000)	(758,000)
Basis diffence in investments	(129,000)	(129,000)
Foreign exchange	(45,000)	$ (35,000)
Other	(12,000)
State income taxes	(75,000)	$ (72,000)
Non-current deferred income tax liabilities	(867,000)	(1,752,000)
Net deferred income tax liability	$ (383,000)	$ (1,266,000)