Note 7 - Cash, Cash Equivalents and Investments (Details) - Fair Value Heirarchy (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Note 7 - Cash, Cash Equivalents and Investments (Details) - Fair Value Heirarchy [Line Items]
Available For Sale Securities	$ 175,621	$ 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	26,028	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	139,750	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	9,843	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	26,028	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	26,028	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	139,750	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	139,750	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	9,843	9,860
Auction Rate Securities [Member]
Note 7 - Cash, Cash Equivalents and Investments (Details) - Fair Value Heirarchy [Line Items]
Available For Sale Securities	$ 9,843	$ 9,860