Note 7 - Cash, Cash Equivalents and Investments (Details) (USD $)	3 Months Ended			3 Months Ended	12 Months Ended	3 Months Ended	12 Months Ended			12 Months Ended	3 Months Ended
	Mar. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Mar. 31, 2014 Temporary [Member]	Dec. 31, 2013 Temporary [Member]	Mar. 31, 2014 Other Than Temporary [Member]	Dec. 31, 2013 Other Than Temporary [Member]	Mar. 31, 2014 Government Backed Securities [Member]	Mar. 31, 2013 Government Backed Securities [Member]	Dec. 31, 2013 Auction Rate [Member]	Mar. 31, 2014 Auction Rate Securities Backed By Student-Loan Notes [Member]	Mar. 31, 2014 Government Backed Securities [Member]	Dec. 31, 2013 Government Backed Securities [Member]
Note 7 - Cash, Cash Equivalents and Investments (Details) [Line Items]
Auction Rate Securities, Noncurrent	$ 9,843,000	$ 9,860,000	$ 9,860,000					$ 0	$ 25,000			$ 9,800,000	$ 9,900,000
Other than Temporary Impairment Losses, Investments				377,000	360,000	30,000	30,000			390,000	407,000
Deferred Compensation Plan Assets	2,570,000	607,000
Deferred Compensation Liability, Current and Noncurrent	2,600,000	600,000
Deferred Compensation Plan Assets Change in Fair Value Expense	36,000
Deferred Compensation Plan Liabilities, Operating Expense	$ 13,000