Note 2 - Basis of Presentation and Revenue Recognition Policy (Details Textual) - USD ($)	Mar. 31, 2021	Dec. 31, 2020
Contract with Customer, Liability, Current	$ 113,000	$ 209,000	[1]

[1] The condensed consolidated balance sheet as of December 31, 2020 has been prepared using information from the audited consolidated balance sheet as of that date.