Note 5 - Leases (Details Textual) $ in Thousands	3 Months Ended	6 Months Ended	9 Months Ended
	Sep. 01, 2019 USD ($)	Sep. 01, 2019 USD ($)	Sep. 01, 2019 USD ($)	Dec. 31, 2018 ft²
Lessee, Operating Lease, Liability, Payments, Remainder of Fiscal Year	$ 78	$ 78	$ 78
Lessee, Operating Lease, Liability, Payments, Due Year Two	61	61	$ 61
Operating Lease, Expense	$ 95	190
Operating Lease, Payments		$ 189
Operating Lease, Weighted Average Remaining Lease Term	6 years 328 days	6 years 328 days	6 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	$ 2,234	$ 2,234	2,234
Construction in Progress, Gross	3,934	3,934	3,934
Accrued Liabilities [Member]
Lessee, Operating Lease, Liability, Payments, Remainder of Fiscal Year	395	395	395
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