Note 7 - Cash, Cash Equivalents and Investments (Details) - Unrealized Gains And Losses On Investments (USD $) In Thousands, unless otherwise specified	3 Months Ended	12 Months Ended
	Mar. 31, 2014	Dec. 31, 2013
Note 7 - Cash, Cash Equivalents and Investments (Details) - Unrealized Gains And Losses On Investments [Line Items]
Adjusted Cost	$ 175,991	$ 173,931
Unrealized Gains	32	26
Unrealized Losses	(402)	(383)
Total Fair Value	175,621	173,574
Fair Value of Investments in Unrealized Loss Position	43,843	52,740
Money Market Funds [Member]
Note 7 - Cash, Cash Equivalents and Investments (Details) - Unrealized Gains And Losses On Investments [Line Items]
Adjusted Cost	26,028	35,588
Unrealized Gains	0	0
Total Fair Value	26,028	35,588
US Government Agencies Short-term Debt Securities [Member]
Note 7 - Cash, Cash Equivalents and Investments (Details) - Unrealized Gains And Losses On Investments [Line Items]
Adjusted Cost	139,743	128,123
Unrealized Gains	32	26
Unrealized Losses	(25)	(23)
Total Fair Value	139,750	128,126
Fair Value of Investments in Unrealized Loss Position	34,000	42,880
Auction Rate Securities [Member]
Note 7 - Cash, Cash Equivalents and Investments (Details) - Unrealized Gains And Losses On Investments [Line Items]
Adjusted Cost	10,220	10,220
Unrealized Losses	(377)	(360)
Total Fair Value	9,843	9,860
Fair Value of Investments in Unrealized Loss Position	$ 9,843	$ 9,860