Note 2 - Cash, Cash Equivalents and Marketable Investments (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
Disclosure Text Block Supplement [Abstract]
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax	$ 8,000	$ 13,000

Amount before tax of unrealized loss in accumulated other comprehensive income (AOCI) on investments in debt and equity securities classified as available-for-sale.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27161-111563

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