Note 5 - Leases (Details Textual) - USD ($)	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Operating Lease, Weighted Average Remaining Lease Term	5 years 73 days
Right-of-Use Asset Obtained in Exchange for Operating Lease Liability	$ 966,000
Operating Lease, Payments	71,000
Operating Lease, Cost	$ 103,000