Note 6 - Right of Use Assets and Lease Liability (Details Textual) - USD ($)	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Jan. 01, 2019
Operating Lease, Weighted Average Discount Rate, Percent	5.00%
Lessee, Operating Lease, Liability, Payments, Due, Total	$ 505,000
Lessee, Operating Lease, Liability, Undiscounted Excess Amount	$ 27,000
Operating Lease, Weighted Average Remaining Lease Term	2 years 109 days
Lease, Cost, Total	$ 109,000
Operating Lease, Cost	88,000
Short-term Lease, Cost	10,000
Variable Lease, Cost	11,000	$ 10,000
Operating Leases, Rent Expense, Net, Total		$ 92,000
Operating Lease, Payments	109,000
Operating Lease, Liability, Total	478,000
Other Assets [Member]
Operating Lease, Right-of-Use Asset	478,000
Other Liabilities [Member]
Operating Lease, Liability, Total	$ 478,000
Accounting Standards Update 2016-02 [Member]
Operating Lease, Right-of-Use Asset			$ 565,000
Operating Lease, Liability, Total			$ 565,000