Note 10 - Deposits - Deposits (Details) - USD ($)	Dec. 31, 2018	Dec. 31, 2017
Demand, weighted average rate	0.82%	0.00%
Demand, balance	$ 142,996,945	$ 94,727,683
Demand, percentage of deposits	19.10%	15.60%
NOW, weighted average rate	1.09%	0.35%
NOW, balance	$ 165,581,134	$ 139,458,528
NOW, percentage of deposits	22.10%	23.00%
Money market, weighted average rate	0.90%	0.73%
Money market, balance	$ 168,845,437	$ 187,064,098
Money market, percentage of deposits	22.50%	30.80%
Savings, weighted average rate	0.30%	0.20%
Savings, balance	$ 39,663,846	$ 30,848,154
Savings, percentage of deposits	5.30%	5.50%
Weighted average rate	1.17%	0.62%
Deposits	$ 749,618,822	$ 607,364,350
Percentage of deposits	100.00%	100.00%
Certificates, weighted average rate	1.79%	1.20%
Certificates, balance	$ 232,531,460	$ 155,265,887
Certificates, percentage of deposits	31.00%	25.60%
Deposits not Including Time Deposits [Member]
Weighted average rate	0.89%	0.42%
Deposits	$ 517,087,362	$ 452,098,463
Percentage of deposits	69.00%	74.40%
Certificates of Deposit, 0 to 0.99% [Member]
Certificates, weighted average rate	0.69%	0.69%
Certificates, balance	$ 46,485,328	$ 46,771,850
Certificates, percentage of deposits	6.20%	7.70%
Certificates Of Deposit 1 To 1.99% [Member]
Certificates, weighted average rate	1.45%	1.39%
Certificates, balance	$ 71,697,342	$ 104,284,007
Certificates, percentage of deposits	9.60%	17.30%
Certificates Of Deposit 2 To 3.99% [Member]
Certificates, weighted average rate	2.46%	2.00%
Certificates, balance	$ 114,348,790	$ 4,210,030
Certificates, percentage of deposits	15.20%	0.70%