Note 7 - Leases - Lease Balance Classifications Within the Consolidated Balance Sheets and Lease Activity (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 27, 2020	Jun. 29, 2019	Dec. 28, 2019
Balance	$ 23,591
Right-of-use assets obtained in exchange for new lease obligations during the period	1,635	$ 298
Reduction in the carrying amount of right-of-use assets during the period	(2,976)	(2,907)
Adjustments for present value and foreign currency effects	54
Balance	22,304
Balance	26,124
Lease liabilities incurred for new lease obligations during the period	1,635
Accretion of lease liabilities	800
Operating cash used by payments on lease liabilities	(3,812)	$ (4,613)
Adjustments for present value, foreign currency, and restructuring liability effects	55
Balance	24,802
Less: Current portion of operating lease liabilities	(4,979)		$ (4,686)
Long-term operating lease liabilities, net of current portion	$ 19,823		$ 21,438