Note 3 - Securities - Summary of Securities (Details) - USD ($)	Mar. 31, 2019	Dec. 31, 2018
Debt securities, amortized cost	$ 99,809,000	$ 99,639,000
Debt securities, gross unrealized gains	206,000	86,000
Debt securities, gross unrealized losses	(1,023,000)	(2,007,000)
Debt securities, fair value	98,992,000	97,718,000
US Treasury and Government [Member]
Debt securities, amortized cost	4,529,000	4,532,000
Debt securities, gross unrealized gains
Debt securities, gross unrealized losses	(57,000)	(87,000)
Debt securities, fair value	4,472,000	4,445,000
US Government-sponsored Enterprises Debt Securities [Member]
Debt securities, amortized cost	14,083,000	17,052,000
Debt securities, gross unrealized gains	24,000	30,000
Debt securities, gross unrealized losses	(164,000)	(299,000)
Debt securities, fair value	13,943,000	16,783,000
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Debt securities, amortized cost	30,905,000	27,666,000
Debt securities, gross unrealized gains	42,000
Debt securities, gross unrealized losses	(142,000)	(490,000)
Debt securities, fair value	30,805,000	27,176,000
Collateralized Mortgage Obligations [Member]
Debt securities, amortized cost	21,866,000	19,440,000
Debt securities, gross unrealized gains	19,000	34,000
Debt securities, gross unrealized losses	(613,000)	(810,000)
Debt securities, fair value	21,272,000	18,664,000
US States and Political Subdivisions Debt Securities [Member]
Debt securities, amortized cost	19,921,000	22,943
Debt securities, gross unrealized gains	101,000	13,000
Debt securities, gross unrealized losses	(15,000)	(224,000)
Debt securities, fair value	20,007,000	22,732,000
Corporate Debt Securities [Member]
Debt securities, amortized cost	8,505,000	8,006,000
Debt securities, gross unrealized gains	20,000	9,000
Debt securities, gross unrealized losses	(32,000)	(97,000)
Debt securities, fair value	$ 8,493,000	$ 7,918,000