Note 3 - Revenue (Details Textual) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Jan. 01, 2019
Contract with Customer, Cumulative Catch-up Adjustment to Revenue, Change in Estimate of Transaction Price and Input Costs	$ 2,100,000
Contract with Customer, Asset, after Allowance for Credit Loss, Total	494,281	$ 512,952	$ 1,400,000
Contract with Customer, Liability, Total	$ 786,657	$ 2,275,236	$ 500,000