Note 10 - Borrowed Funds - Outstanding Advances (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Amount	$ 11,012,000	$ 21,768,507
Amount	$ 3,000,000	$ 17,000,000
Federal Home Loan Bank advances	1.50%	1.35%
Federal Home Loan Bank advances	$ 19,000,000	$ 18,000,000
Federal Home Loan Bank, Advances, Activity for Year, Average Balance of Agreements Outstanding	$ 8,795,890	$ 13,846,575
Average rate, federal Home Loan Bank advances	1.50%	1.20%
Investment securities underlying the repurchase agreements at year end: Carrying value	$ 11,706,765	$ 22,363,793
Investment securities underlying the repurchase agreements at year end: Estimated fair value	11,710,458	22,484,092
Loans pledged to the Federal Home Loan Bank at year-end: Carrying value - loans	63,305,452	68,406,154
Loans pledged to the Federal Home Loan Bank at year-end: Carrying value - investment securities		4,749,970
Loans pledged to the Federal Reserve Bank at year-end: Carrying value	$ 50,682,236	40,717,623
Federal Home Loan Bank Advances at 1.13% Due in 2018[Member]
Interest Rate	1.13%
Label 7	Jan. 16, 2018
Amount		1,000,000
Federal Home Loan Bank Advances at 1.25% Due in 2018 [Member]
Interest Rate	1.25%
Label 7	Jan. 30, 2018
Amount		2,000,000
Federal Home Loan Bank Advances at 1.14% Due in 2018 [Member]
Interest Rate	1.14%
Label 7	Feb. 12, 2018
Amount		2,000,000
Federal Home Loan Bank Advances at 1.17% Due in 2018 [Member]
Interest Rate	1.17%
Label 7	Mar. 15, 2018
Amount		2,000,000
Federal Home Loan Bank Advances at 1.26% Due in 2018 [Member]
Interest Rate	1.26%
Label 7	May 24, 2018
Amount		2,000,000
Federal Home Loan Bank Advances at 1.69% Due in 2018 [Member]
Interest Rate	169.00%
Label 7	Jun. 28, 2018
Amount		3,000,000
Federal Home Loan Bank Advances at 1.32% Due in 2018 [Member]
Interest Rate	132.00%
Label 7	Aug. 13, 2018
Amount		2,000,000
Federal Home Loan Bank Advances at 1.25% Due in 2019 [Member]
Interest Rate	125.00%
Label 7	Sep. 23, 2019
Amount	$ 2,000,000	2,000,000
Federal Home Loan Bank Advances at 1.99% Due in 2019 [Member]
Interest Rate	199.00%
Label 7	Nov. 22, 2019
Amount	$ 1,000,000	$ 1,000,000
Securities Sold under Agreements to Repurchase [Member]
Securities sold under repurchase agreements	1.07%	0.65%
Securities sold under repurchase agreements	$ 22,173,010	$ 30,786,064
Short-term Debt, Average Outstanding Amount	$ 17,479,418	$ 24,702,931
Average rate, securities sold under repurchase agreements	0.83%	0.66%
Borrowings from FRB and Commercial Banks [Member]
Short-term Debt, Average Outstanding Amount	$ 249,047	$ 78,082
Average rate, securities sold under repurchase agreements	1.93%	1.64%