Note 4 - Marketable Securities (Details) - Available-for-sale marketable securities (USD $)	9 Months Ended
	Sep. 30, 2013	Dec. 31, 2012
Available-for-sale marketable securities [Abstract]
Cost basis	$ 255,000
Unrealized gains included in accumulated other comprehensive income	612,000
Fair value	$ 867,000	$ 293,000	[1]

[1] The condensed consolidated balance sheet as of December 31, 2012 has been prepared using information from the audited consolidated balance sheet as of that date.