Note 4 - Accounts Receivable, Transit Accounts Receivable and Transit Accounts Payable - Accounts Receivable (Details) - USD ($) $ in Thousands	Sep. 28, 2019	Dec. 29, 2018
Allowance for sales discounts and doubtful accounts	$ (1,545)	$ (1,443)
Accounts receivable, net	57,470	52,335
Billed Revenues [Member]
Accounts receivable, current	25,889	32,323
Unbilled Revenues [Member]
Accounts receivable, current	17,191	10,383
Work In Progress [Member]
Accounts receivable, current	3,758	2,252
Accounts Receivable Subject to Arbitration [Member]
Accounts receivable, current	$ 12,177	$ 8,820