Note 6 - Financial Instruments and Fair Value (Details) - Investment in Auction Rate Securities - Fair Value (Auction Rate Securities [Member], USD $) In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Note 6 - Financial Instruments and Fair Value (Details) - Investment in Auction Rate Securities - Fair Value [Line Items]
Investment in auction rate securities	$ 6,905us-gaap_AvailableForSaleSecurities	$ 6,905us-gaap_AvailableForSaleSecurities
Fair Value, Inputs, Level 3 [Member]
Note 6 - Financial Instruments and Fair Value (Details) - Investment in Auction Rate Securities - Fair Value [Line Items]
Investment in auction rate securities	$ 6,905	$ 6,905

Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 25

-Paragraph 1

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=51813488&loc=d3e22054-111558

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 50

-Paragraph 5

-Subparagraph (aa)

-URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27232-111563

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 45

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=49167202&loc=d3e26610-111562

Name:	us-gaap_AvailableForSaleSecurities
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant