Note 5 - Revenue Recognition (Details Textual) - USD ($)	3 Months Ended
	Mar. 31, 2020	Dec. 31, 2019
Period of Payment Terms Offered to Customers Distributions and Resellers Domestically (Day)	30 days
Period of Payment Terms Offered to Customers Distributors and Resllers Internationally (Day)	45 days
Contract with Customer, Asset, after Allowance for Credit Loss, Current, Total	$ 1,032,000	$ 1,566,000
Contract with Customer, Liability, Current	$ 284,000	$ 516,000