Note 6 - Leases (Details Textual) $ in Thousands	1 Months Ended	12 Months Ended
	Aug. 31, 2020 USD ($) ft²	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Mar. 31, 2017 ft²
Short-term and Variable Lease, Cost		$ 400
Lease, Cost, Total		1,800	$ 1,600
Operating Lease, Payments		$ 3,000	2,500
Operating Lease, Weighted Average Remaining Lease Term (Year)		1 year 10 months 24 days
Operating Lease, Weighted Average Discount Rate, Percent		7.62%
Sublease Income		$ 2,900	1,000
Proceeds from Lease Payment, Operating Activity		$ 2,800	$ 900
The 1020 Marsh Road Facility [Member]
Area of Real Estate Property (Square Foot) | ft²				34,500
Lessee, Operating Lease, Term of Contract (Month)				87 months
Lessee, Operating Lease, Number of Renewal Options				1
Lessee, Operating Lease, Renewal Term (Year)				5 years
Office Space in North Carolina [Member]
Area of Real Estate Property (Square Foot) | ft²	4,128
Lessee, Operating Lease, Term of Contract (Month)	63 months
Lessee, Operating Lease, Monthly Payments	$ 9
Lessee, Operating Lease, Abatement Term (Month)	3 months