Note 17 - Fair Value and Interest Rate Risk - Financial Assets Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Available-for-sale securities	$ 25,576	$ 24,428
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Available-for-sale securities	7,224	10,441
Corporate Debt Securities [Member]
Available-for-sale securities	13,804	8,961
Subordinated Notes [Member]
Available-for-sale securities	4,548	5,026
Fair Value, Measurements, Recurring [Member]
Available-for-sale securities	25,576	24,428
Fair Value, Measurements, Recurring [Member] | Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Available-for-sale securities	7,224	10,441
Fair Value, Measurements, Recurring [Member] | Corporate Debt Securities [Member]
Available-for-sale securities	13,804	8,961
Fair Value, Measurements, Recurring [Member] | Subordinated Notes [Member]
Available-for-sale securities	4,548	5,026
Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring [Member]
Available-for-sale securities
Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring [Member] | Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Available-for-sale securities
Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring [Member] | Corporate Debt Securities [Member]
Available-for-sale securities
Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring [Member] | Subordinated Notes [Member]
Available-for-sale securities
Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring [Member]
Available-for-sale securities	25,576	22,428
Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring [Member] | Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Available-for-sale securities	7,224	10,441
Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring [Member] | Corporate Debt Securities [Member]
Available-for-sale securities	13,804	8,961
Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring [Member] | Subordinated Notes [Member]
Available-for-sale securities	4,548	3,026
Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member]
Available-for-sale securities		2,000
Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member] | Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Available-for-sale securities
Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member] | Corporate Debt Securities [Member]
Available-for-sale securities
Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member] | Subordinated Notes [Member]
Available-for-sale securities		$ 2,000