Note 4 - Loans and Allowance for Loan Losses - Analysis of Changes in the Allowance for Loan Losses (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Balance at beginning of period	$ 5,520	$ 4,485	$ 4,465	$ 4,198
Loan charge-offs	(60)	(37)	(156)	(175)
Recoveries	60	13	161	83
Net loan recoveries (charge-offs)	0	(24)	5	(92)
Provision charged to operations	525	180	1,575	535
Balance	6,045	4,641	6,045	4,641
Individually evaluated for impairment	579		579		$ 579
Collectively evaluated for impairment	5,466		5,466		3,886
Individually evaluated for impairment	7,118		7,118		7,849
Collectively evaluated for impairment	527,028		527,028		510,867
Total ending loans balance	534,146		534,146
Commercial Portfolio Segment [Member]
Balance at beginning of period	1,832	1,717	1,756	1,232
Loan charge-offs	(1)	0	(2)	0
Recoveries	8	0	8	28
Net loan recoveries (charge-offs)	7	0	6	28
Provision charged to operations	10	84	87	541
Balance	1,849	1,801	1,849	1,801
Individually evaluated for impairment	579		579		579
Collectively evaluated for impairment	1,270		1,270		1,177
Individually evaluated for impairment	4,645		4,645		4,909
Collectively evaluated for impairment	118,758		118,758		94,955
Total ending loans balance	123,403		123,403
Commercial Real Estate Portfolio Segment [Member]
Balance at beginning of period	3,045	2,165	2,130	2,414
Loan charge-offs	0	0	0	0
Recoveries	0	0	19	0
Net loan recoveries (charge-offs)	0	0	19	0
Provision charged to operations	548	94	1,444	(155)
Balance	3,593	2,259	3,593	2,259
Individually evaluated for impairment	0		0		0
Collectively evaluated for impairment	3,593		3,593		2,130
Individually evaluated for impairment	2,473		2,473		2,940
Collectively evaluated for impairment	300,931		300,931		299,144
Total ending loans balance	303,404		303,404
Residential Portfolio Segment [Member]
Balance at beginning of period	401	368	334	314
Loan charge-offs	0	0	0	(29)
Recoveries	0	0	25	0
Net loan recoveries (charge-offs)	0	0	25	(29)
Provision charged to operations	(21)	(23)	21	60
Balance	380	345	380	345
Individually evaluated for impairment	0		0		0
Collectively evaluated for impairment	380		380		334
Individually evaluated for impairment	0		0		0
Collectively evaluated for impairment	79,808		79,808		87,172
Total ending loans balance	79,808		79,808
Consumer Portfolio Segment [Member]
Total ending loans balance	303,404		303,404
Consumer Portfolio Segment [Member] | Home Equity Loan [Member]
Balance at beginning of period	101	98	104	115
Loan charge-offs	0	0	0	0
Recoveries	0	1	1	2
Net loan recoveries (charge-offs)	0	1	1	2
Provision charged to operations	(1)	2	(5)	(16)
Balance	100	101	100	101
Individually evaluated for impairment	0		0		0
Collectively evaluated for impairment	100		100		104
Individually evaluated for impairment	0		0		0
Collectively evaluated for impairment	23,749		23,749		25,856
Total ending loans balance	23,749		23,749
Consumer Portfolio Segment [Member] | Other Loan [Member]
Balance at beginning of period	141	137	141	123
Loan charge-offs	(59)	(37)	(154)	(146)
Recoveries	52	12	108	53
Net loan recoveries (charge-offs)	(7)	(25)	(46)	(93)
Provision charged to operations	(11)	23	28	105
Balance	123	$ 135	123	$ 135
Individually evaluated for impairment	0		0		0
Collectively evaluated for impairment	123		123		141
Individually evaluated for impairment	0		0		0
Collectively evaluated for impairment	3,782		3,782		$ 3,740
Total ending loans balance	$ 3,782		$ 3,782