Note 10 - Commitments and Contingencies (Details Textual) - USD ($)	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019
Letters of Credit Outstanding, Amount	$ 230,000
Office Space [Member]
Operating Lease, Expense	$ 29,000	$ 29,000

Amount of operating lease expense. Excludes sublease income.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 45
-Paragraph 4
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=121603541&loc=SL77918638-209977

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