Note 7 - Cash, Cash Equivalents and Investments (Details) - Fair Value Heirarchy (USD $) In Thousands, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Note 7 - Cash, Cash Equivalents and Investments (Details) - Fair Value Heirarchy [Line Items]
Available For Sale Securities	$ 173,824	$ 173,574
Fair Value, Inputs, Level 1 [Member]
Note 7 - Cash, Cash Equivalents and Investments (Details) - Fair Value Heirarchy [Line Items]
Available For Sale Securities	30,964	35,588
Fair Value, Inputs, Level 2 [Member]
Note 7 - Cash, Cash Equivalents and Investments (Details) - Fair Value Heirarchy [Line Items]
Available For Sale Securities	133,012	128,126
Fair Value, Inputs, Level 3 [Member]
Note 7 - Cash, Cash Equivalents and Investments (Details) - Fair Value Heirarchy [Line Items]
Available For Sale Securities	9,848	9,860
Money Market Funds [Member] | Fair Value, Inputs, Level 1 [Member]
Note 7 - Cash, Cash Equivalents and Investments (Details) - Fair Value Heirarchy [Line Items]
Available For Sale Securities	30,964	35,588
Money Market Funds [Member] | Fair Value, Inputs, Level 2 [Member]
Note 7 - Cash, Cash Equivalents and Investments (Details) - Fair Value Heirarchy [Line Items]
Available For Sale Securities	0	0
Money Market Funds [Member] | Fair Value, Inputs, Level 3 [Member]
Note 7 - Cash, Cash Equivalents and Investments (Details) - Fair Value Heirarchy [Line Items]
Available For Sale Securities	0	0
Money Market Funds [Member]
Note 7 - Cash, Cash Equivalents and Investments (Details) - Fair Value Heirarchy [Line Items]
Available For Sale Securities	30,964	35,588
US Government Agencies Short-term Debt Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Note 7 - Cash, Cash Equivalents and Investments (Details) - Fair Value Heirarchy [Line Items]
Available For Sale Securities	0	0
US Government Agencies Short-term Debt Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Note 7 - Cash, Cash Equivalents and Investments (Details) - Fair Value Heirarchy [Line Items]
Available For Sale Securities	133,012	128,126
US Government Agencies Short-term Debt Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Note 7 - Cash, Cash Equivalents and Investments (Details) - Fair Value Heirarchy [Line Items]
Available For Sale Securities	0	0
US Government Agencies Short-term Debt Securities [Member]
Note 7 - Cash, Cash Equivalents and Investments (Details) - Fair Value Heirarchy [Line Items]
Available For Sale Securities	133,012	128,126
Auction Rate Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Note 7 - Cash, Cash Equivalents and Investments (Details) - Fair Value Heirarchy [Line Items]
Available For Sale Securities	0	0
Auction Rate Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Note 7 - Cash, Cash Equivalents and Investments (Details) - Fair Value Heirarchy [Line Items]
Available For Sale Securities	0	0
Auction Rate Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Note 7 - Cash, Cash Equivalents and Investments (Details) - Fair Value Heirarchy [Line Items]
Available For Sale Securities	9,848	9,860
Auction Rate Securities [Member]
Note 7 - Cash, Cash Equivalents and Investments (Details) - Fair Value Heirarchy [Line Items]
Available For Sale Securities	$ 9,848	$ 9,860