Note 3 - Marketable Securities (Details) - Fair Value, Financial Assets Measured by Level within The Fair Value Hierarchy (USD $) In Thousands, unless otherwise specified	9 Months Ended	12 Months Ended
	Sep. 30, 2013	Dec. 31, 2012
Note 3 - Marketable Securities (Details) - Fair Value, Financial Assets Measured by Level within The Fair Value Hierarchy [Line Items]
Cost	$ 4,283	$ 4,850
Unrealized Gain	0	4
Estimated Fair Value	4,283	4,854
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	467	952
Unrealized Gain	0	3
Estimated Fair Value	467	955
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	316	698
Unrealized Gain	0	1
Estimated Fair Value	316	699
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	3,500	3,200
Unrealized Gain	0	0
Estimated Fair Value	$ 3,500	$ 3,200