Note 8 - Leases (Details Textual) $ in Thousands	12 Months Ended
	Dec. 31, 2019 USD ($) ft²	Dec. 31, 2018 USD ($)
Operating Leases, Rent Expense, Net, Total	$ 1,700	$ 1,700
Operating Leases, Rent Expense, Sublease Rentals	$ 5,100	$ 5,100
Lessee, Operating Lease, Term of Contract	15 years
Area Under Operating Lease, Gross | ft²	335,372
Area Under Operating Lease, Net | ft²	254,710
Tenant Improvements	$ 21,200
Capital Lease Obligations, Total	$ 0