Note 9 - Fair Value Measurements - Carrying Amounts and Estimated Fair Values of Financial Instruments (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Total , Estimated fair value	$ 112,329	$ 101,595
Reported Value Measurement [Member]
Cash and cash equivalents	68,851	62,646
Total , Estimated fair value	112,329	101,595
Loans, net	471,418	456,580
FHLB stock	2,685	2,438
Accrued interest receivable	2,059	2,312
Deposits	616,159	582,353
Repurchase agreements	4,325	7,547
Note payable		2,375
Junior subordinated deferrable interest debentures	10,310	10,310
Accrued interest payable	58	59
Estimate of Fair Value Measurement [Member]
Cash and cash equivalents	68,851	62,646
Total , Estimated fair value	112,329	101,595
Loans, net	471,540	459,618
Accrued interest receivable	2,059	2,312
Deposits	616,173	582,336
Repurchase agreements	4,325	7,547
Note payable		2,375
Junior subordinated deferrable interest debentures	7,680	7,762
Accrued interest payable	58	59
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 1 [Member]
Cash and cash equivalents	68,851	62,646
Accrued interest receivable	11	7
Deposits	569,729	532,750
Accrued interest payable	9	9
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 2 [Member]
Total , Estimated fair value	112,329	101,595
Accrued interest receivable	463	398
Deposits	46,444	49,586
Repurchase agreements	4,325	7,547
Accrued interest payable	36	36
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 3 [Member]
Loans, net	471,540	459,618
Accrued interest receivable	1,585	1,907
Note payable		2,375
Junior subordinated deferrable interest debentures	7,680	7,762
Accrued interest payable	$ 13	$ 14