Note 3 - Marketable Securities (Details) - Fair Value, Financial Assets Measured by Level within The Fair Value Hierarchy (USD $) In Thousands, unless otherwise specified	3 Months Ended	12 Months Ended
	Mar. 31, 2014	Dec. 31, 2013
Note 3 - Marketable Securities (Details) - Fair Value, Financial Assets Measured by Level within The Fair Value Hierarchy [Line Items]
Cost	$ 4,616	$ 5,119
Unrealized Gain	1	2
Estimated Fair Value	4,617	5,121
Asset-backed Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Note 3 - Marketable Securities (Details) - Fair Value, Financial Assets Measured by Level within The Fair Value Hierarchy [Line Items]
Cost	442	455
Unrealized Gain	1	1
Estimated Fair Value	443	456
Corporate Debt Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Note 3 - Marketable Securities (Details) - Fair Value, Financial Assets Measured by Level within The Fair Value Hierarchy [Line Items]
Cost	164	164
Unrealized Gain	0	1
Estimated Fair Value	164	165
US Treasury Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Note 3 - Marketable Securities (Details) - Fair Value, Financial Assets Measured by Level within The Fair Value Hierarchy [Line Items]
Cost	4,010	4,500
Unrealized Gain	0	0
Estimated Fair Value	$ 4,010	$ 4,500