Note 7 - Leases (Details Textual) - USD ($)	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Lessee, Operating Lease, Number of Right-of-Use Leases	5
Lessee, Operating Lease, Number of Right-of-Use Leases, Subleased	1
Lessee, Operating Lease, Number Leases Exceeding One Year	3
Lessee, Operating Lease, Number Leases Exceeding Less than One Year	3
Operating Lease, Weighted Average Discount Rate, Percent	10.50%
Operating Lease, Weighted Average Remaining Lease Term	1 year 164 days
Short-term Lease Commitment, Amount	$ 4,000
Lessee, Finance Lease, Number of Leases	0
Operating Lease, Payments	$ 199,000	$ 146,000