Note 5 - Leases (Details Textual) $ in Thousands	3 Months Ended	9 Months Ended	12 Months Ended
	Dec. 01, 2019 USD ($)	Dec. 01, 2019 USD ($)	Dec. 01, 2019 USD ($)	Dec. 31, 2018 ft²
Lessee, Operating Lease, Liability, Payments, Remainder of Fiscal Year	$ 38	$ 38	$ 38
Lessee, Operating Lease, Liability, Payments, Due Year Two	152	152	$ 152
Operating Lease, Expense	$ 88	278
Operating Lease, Payments		$ 274
Operating Lease, Weighted Average Remaining Lease Term	5 years 328 days	5 years 328 days	5 years 328 days
Additional Manufacturing Facility [Member]
Area of Land | ft²				90,000
Construction in Progress Expenditures Incurred but Not yet Paid			$ 20,000
Purchase Obligation, Total	$ 1,170	$ 1,170	1,170
Construction in Progress, Gross	5,385	5,385	5,385
Accrued Liabilities [Member]
Lessee, Operating Lease, Liability, Payments, Remainder of Fiscal Year	199	199	199
Lessee, Operating Lease, Liability, Payments, Due Year Two	$ 463	$ 463	$ 463
Minimum [Member]
Lessee, Operating Lease, Renewal Term	1 year	1 year	1 year
Maximum [Member]
Lessee, Operating Lease, Renewal Term	10 years	10 years	10 years