Note 3 - Investments (Details Textual) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Proceeds from Sale and Maturity of Marketable Securities	$ 0	$ 440,000
Available-for-sale Securities, Current	656,000	2,840,000
Marketable Securities, Unrealized Gain (Loss)	(1,523,000)	995,000
Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, Tax	$ (835,000)	$ 382,000
Class of Warrant or Right, Number of Securities Called by Warrants or Rights	167,500