Note 4 - Other Assets (Details Textual) - USD ($)	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017
Prepaid Rent [Member]
Amortization of Deferred Charges, Total	$ 115,000	$ 115,000

The amount of amortization of deferred charges applied against earnings during the period.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.3)
-URI http://asc.fasb.org/extlink&oid=115205541&loc=SL114868664-224227

Name:	us-gaap_AmortizationOfDeferredCharges
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration