Note 10 - Financial Instruments (Details Textual) Pure in Thousands, $ in Thousands	Jun. 30, 2021 USD ($)	Dec. 31, 2020 USD ($)
Number of Derivative Instruments Held	0	0
Fair Value, Recurring [Member]
Financial and Nonfinancial Liabilities, Fair Value Disclosure	$ 0	$ 0

Fair value of financial and nonfinancial obligations.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123874694&loc=d3e19207-110258

Name:	us-gaap_LiabilitiesFairValueDisclosure
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant