Note 4 - Accounts Receivable, Transit Accounts Receivable and Transit Accounts Payable - Accounts Receivable (Details) - USD ($) $ in Thousands	Dec. 30, 2017	Dec. 31, 2016
Allowance for sales discounts and doubtful accounts	$ (967)	$ (1,402)
Accounts receivable, net	46,080	45,170
Billed Revenues [Member]
Accounts receivable, current	31,448	34,463
Unbilled Revenues [Member]
Accounts receivable, current	10,573	6,894
Work In Progress [Member]
Accounts receivable, current	$ 5,026	$ 5,215