Note 2 - Significant Accounting Policies (Details) - Amortized Cost, Unrealized Gains or Losses, and Estimated Fair Value of Cash, Cash Equivalents and Investments (USD $)
In Thousands, unless otherwise specified
 12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Note 2 - Significant Accounting Policies (Details) - Amortized Cost, Unrealized Gains or Losses, and Estimated Fair Value of Cash, Cash Equivalents and Investments [Line Items]    
Cash, Amortized Cost $ 6,351 $ 3,221
Cash, Fair Value 6,351 3,221
Money Market Funds, Amortized Cost 4,103 6,058
Money Market Funds, Fair Value 4,103 6,058
Debt securities, Amortized Cost 57,388 69,326
Debt securities, Gross Unrealized Gains 3 22
Debt securities, Gross Unrealized Losses (28) (7)
Debt securities, Fair Value 57,363 69,341
Total, Amortized Cost 63,739 72,547
Total, Gross Unrealized Gains 3 22
Total, Gross Unrealized Losses (28) (7)
Total, Fair Value 63,714 72,562
US Government Agencies Debt Securities [Member]    
Note 2 - Significant Accounting Policies (Details) - Amortized Cost, Unrealized Gains or Losses, and Estimated Fair Value of Cash, Cash Equivalents and Investments [Line Items]    
Debt securities, Amortized Cost 43,862 49,878
Debt securities, Gross Unrealized Gains 1 18
Debt securities, Gross Unrealized Losses (19) (6)
Debt securities, Fair Value 43,844 49,890
Total, Gross Unrealized Gains 1 18
Total, Gross Unrealized Losses (19) (6)
Corporate Debt Securities [Member]    
Note 2 - Significant Accounting Policies (Details) - Amortized Cost, Unrealized Gains or Losses, and Estimated Fair Value of Cash, Cash Equivalents and Investments [Line Items]    
Debt securities, Amortized Cost 9,423 13,390
Debt securities, Gross Unrealized Gains 2 4
Debt securities, Gross Unrealized Losses (9) (1)
Debt securities, Fair Value 9,416 13,393
Total, Gross Unrealized Gains 2 4
Total, Gross Unrealized Losses $ (9) $ (1)