Note 4 - Investments - Available-for-Sale Marketable Securities (Details) - USD ($)	6 Months Ended	12 Months Ended
	Jun. 30, 2015	Dec. 31, 2014
Marketable Securities [Member]
Cost basis	$ 342,000	$ 327,000
Gains previously recognized on warrants	380,000	380,000
Gains included in accumulated other comprehensive income	773,000	2,133,000
Available-for-sale Securities, Current	1,495,000	2,840,000
Available-for-sale Securities, Current	$ 1,495,000	$ 2,840,000	[1]

[1] The condensed consolidated balance sheet as of December 31, 2014 has been prepared using information from the audited consolidated balance sheet as of that date.