Note 7 - Leases (Details Textual) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Lessee, Operating Lease, Number of Right-of-Use Leases	5		5
Lessee, Operating Lease, Number of Right-of-Use Leases, Subleased	1		1
Lessee, Operating Lease, Number Leases Exceeding One Year	3		3
Lessee, Operating Lease, Number Leases Exceeding Less than One Year	3		3
Lessee, Operating Lease, Renewal Term	5 years		5 years
Operating Lease, Weighted Average Discount Rate, Percent	10.50%		10.50%
Operating Lease, Weighted Average Remaining Lease Term	1 year 116 days		1 year 116 days
Short-term Lease Commitment, Amount	$ 1,000		$ 1,000
Lessee, Finance Lease, Number of Leases	0		0
Operating Lease, Payments	$ 200,000	$ 222,000	$ 399,000	$ 368,000