Note 5 - Leases (Details Textual) $ in Thousands	1 Months Ended	3 Months Ended
	Dec. 31, 2018 USD ($) ft²	May 30, 2021 USD ($)
Operating Lease, Expense		$ 15
Operating Lease, Payments		$ 13
Operating Lease, Weighted Average Remaining Lease Term (Year)		14 years 73 days
Additional Manufacturing Facility [Member]
Area of Land (Square Foot) | ft²	90,000
Construction in Progress Estimated Cost	$ 18,800
Purchase Obligation, Total		$ 752
Construction in Progress, Gross		16,346
Accrued Liabilities, Current [Member]
Lessee, Operating Lease, Liability, to be Paid, Year One		$ 157
Minimum [Member]
Lessee, Operating Lease, Renewal Term (Year)		1 year
Maximum [Member]
Lessee, Operating Lease, Renewal Term (Year)		10 years