Note 2 - Business Acquisitions - Fair Value of Contingent Consideration (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 30, 2017	Dec. 30, 2017	Dec. 31, 2016	Dec. 26, 2015
Adjustment to contingent consideration liability		$ 1,423
Kita Manufacturing Co. LTD. and Kita USA, Inc. [Member]
Balance for contingent consideration	$ 823
Settlement of contingent consideration
Adjustment to contingent consideration liability	1,423
Impact of currency exchange	7
Balance for contingent consideration	$ 2,253	$ 2,253