Note 5 - Leases (Details Textual) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2019	Jun. 30, 2018
Operating Lease, Weighted Average Remaining Lease Term	4 years 328 days		4 years 328 days
Right-of-Use Asset Obtained in Exchange for Operating Lease Liability		$ 966,000	$ 966,000
Operating Lease, Payments	$ 72,000		143,000
Operating Lease, Cost	$ 103,000		$ 206,000