Note 7 - Leases (Details Textual) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Lessee, Operating Lease, Number of Right-of-Use Leases	5		5
Lessee, Operating Lease, Number of Right-of-Use Leases, Terminated	1		1
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, Renewal Term (Year)	5 years		5 years
Operating Lease, Weighted Average Discount Rate, Percent	10.34%		10.34%
Operating Lease, Weighted Average Remaining Lease Term (Year)	2 years 211 days		2 years 211 days
Lessee, Finance Lease, Number of Leases	0		0
Short-term Lease Commitment, Amount	$ 0		$ 0
Operating Lease, Payments	$ 243,000	$ 253,000	$ 717,000	$ 740,000