Note 2 - Fair Value of Financial Assets (Details) - USD ($)	Dec. 31, 2015	Dec. 31, 2014
Marketable Securities [Member] \| Fair Value, Inputs, Level 1 [Member]
Available-for-sale Securities, Current	$ 656,000	$ 2,840,000
Marketable Securities [Member]
Available-for-sale Securities, Current	656,000	2,840,000
Available-for-sale Securities, Current	$ 656,000	$ 2,840,000

Amount of investment in debt and equity securities categorized neither as trading securities nor held-to-maturity securities and intended be sold or mature one year or operating cycle, if longer.

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 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=49167202&loc=d3e26626-111562

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