Note 8 - Fair Value Measurements (Details) - Fair Value Heirarchy (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Note 8 - Fair Value Measurements (Details) - Fair Value Heirarchy [Line Items]
Available For Sale Securities	$ 115,323	$ 113,235
Fair Value, Inputs, Level 1 [Member]
Note 8 - Fair Value Measurements (Details) - Fair Value Heirarchy [Line Items]
Available For Sale Securities	15,741	15,959
Fair Value, Inputs, Level 2 [Member]
Note 8 - Fair Value Measurements (Details) - Fair Value Heirarchy [Line Items]
Available For Sale Securities	87,884	85,521
Fair Value, Inputs, Level 3 [Member]
Note 8 - Fair Value Measurements (Details) - Fair Value Heirarchy [Line Items]
Available For Sale Securities	11,698	11,755
Money Market Funds [Member] | Fair Value, Inputs, Level 1 [Member]
Note 8 - Fair Value Measurements (Details) - Fair Value Heirarchy [Line Items]
Available For Sale Securities	15,741	15,959
Money Market Funds [Member]
Note 8 - Fair Value Measurements (Details) - Fair Value Heirarchy [Line Items]
Available For Sale Securities	15,741	15,959
US Government Agencies Short-term Debt Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Note 8 - Fair Value Measurements (Details) - Fair Value Heirarchy [Line Items]
Available For Sale Securities	87,884	85,521
US Government Agencies Short-term Debt Securities [Member]
Note 8 - Fair Value Measurements (Details) - Fair Value Heirarchy [Line Items]
Available For Sale Securities	87,884	85,521
Auction Rate Preferred Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Note 8 - Fair Value Measurements (Details) - Fair Value Heirarchy [Line Items]
Available For Sale Securities	11,698	11,755
Auction Rate Preferred Securities [Member]
Note 8 - Fair Value Measurements (Details) - Fair Value Heirarchy [Line Items]
Available For Sale Securities	$ 11,698	$ 11,755