Note 4 - Accounts Receivable, Transit Accounts Receivable and Transit Accounts Payable - Accounts Receivable (Details) - USD ($) $ in Thousands	Mar. 30, 2019	Dec. 29, 2018
Allowance for sales discounts and doubtful accounts	$ (1,431)	$ (1,443)
Accounts receivable, net	58,613	52,335
Billed Revenues [Member]
Accounts receivable, current	30,344	32,323
Unbilled Revenues [Member]
Accounts receivable, current	17,180	10,383
Work In Progress [Member]
Accounts receivable, current	2,954	2,252
Accounts Receivable Subject to Arbitration [Member]
Accounts receivable, current	$ 9,566	$ 8,820