Note 3 - Available-for-Sale Marketable Securities (Details) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Marketable Securities [Member]
Cost basis	$ 502,000	$ 327,000
Gain previously recognized on warrants	380,000	380,000
Gain (loss) included in accumulated other comprehensive income (loss)	(226,000)	2,133,000
Available-for-sale Securities, Current	656,000	2,840,000
Available-for-sale Securities, Current	$ 656,000	$ 2,840,000