Note 5 - Leases (Details Textual) $ in Thousands	1 Months Ended	3 Months Ended		6 Months Ended
	Aug. 31, 2020 USD ($) ft²	Jun. 30, 2023 USD ($)	Jun. 30, 2022 USD ($)	Jun. 30, 2023 USD ($)	Jun. 30, 2022 USD ($)	Mar. 31, 2017 ft²
Short-term and Variable Lease, Cost				$ 200
Lease, Cost				1,000	$ 900
Operating Lease, Payments				$ 1,500
Operating Lease, Weighted Average Remaining Lease Term (Year)		1 year 4 months 24 days		1 year 4 months 24 days
Operating Lease, Weighted Average Discount Rate, Percent		7.60%		7.60%
Sublease Income		$ 700	$ 700	$ 1,400	$ 1,400
Proceeds from Lease Payment, Operating Activity				$ 1,400
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