Note 4 - Accounts Receivable, Transit Accounts Receivable and Transit Accounts Payable - Accounts Receivable (Details) - USD ($) $ in Thousands	Jun. 29, 2019	Dec. 29, 2018
Allowance for sales discounts and doubtful accounts	$ (1,492)	$ (1,443)
Accounts receivable, net	58,230	52,335
Billed Revenues [Member]
Accounts receivable, current	32,270	32,323
Unbilled Revenues [Member]
Accounts receivable, current	12,620	10,383
Work In Progress [Member]
Accounts receivable, current	3,628	2,252
Accounts Receivable Subject to Arbitration [Member]
Accounts receivable, current	$ 11,204	$ 8,820