Note 7 - Leases (Details Textual) - USD ($)	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020	Jan. 01, 2019
Operating Lease, Right-of-Use Asset	$ 693,000		$ 730,000
Operating Lease, Payments	76,000	$ 74,000
Operating Lease, Cost	$ 109,000	$ 103,000
Accounting Standards Update 2016-02 [Member]
Operating Lease, Right-of-Use Asset				$ 966,000