Note 8 - Treasury Stock (Details Textual) - USD ($) $ / shares in Units, $ in Thousands			12 Months Ended			108 Months Ended
	Dec. 12, 2018	Aug. 01, 2018	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2016	Dec. 31, 2020	Dec. 31, 2013	Dec. 31, 2012
Stock Repurchase Program, Number of Shares Authorized to be Repurchased (in shares)					1,500,000		1,000,000	500,000
Stock Repurchase Program, Additional Shares Authorized (in shares)					500,000
Treasury Stock, Shares, Acquired (in shares)	50,000	100,000	4,833			1,314,694
Treasury Stock Acquired, Average Cost Per Share (in dollars per share)			$ 4.04			$ 4.85
Treasury Stock, Value, Acquired, Cost Method			$ 19	$ 259		$ 6,400
Stock Repurchase Program, Remaining Number of Shares Authorized to be Repurchased (in shares)			185,306			185,306