Note 3 - Revenue From Contracts With Customers (Details Textual) $ in Thousands		6 Months Ended
	Jul. 01, 2018 USD ($)	Dec. 31, 2019 USD ($)
Adjustments to Additional Paid in Capital, Dividends in Excess of Retained Earnings	$ 0
Contract with Customer, Asset, after Allowance for Credit Loss, Total		$ 0
Contract with Customer, Liability, Total		$ 600
Number of Reportable Segments		2
Prepaid Expenses and Other Current Assets [Member]
Contract with Customer, Right to Recover Product, Total		$ 100
Accrued Expenses [Member]
Contract with Customer, Refund Liability, Total		$ 200