Note 1 - Nature of operations (Details)	3 Months Ended
Mar. 31, 2021
Details
Entity Incorporation, State or Country Code	DE
Entity Incorporation, Date of Incorporation	Jul. 29, 1994

Two-character EDGAR code representing the state or country of incorporation.

No definition available.

Name:	dei_EntityIncorporationStateCountryCode
Namespace Prefix:	dei_
Data Type:	dei:edgarStateCountryItemType
Balance Type:	na
Period Type:	duration