Income taxes - Narrative (Details) - USD ($) $ in Thousands	Jan. 03, 2026	Dec. 28, 2024
Operating Loss Carryforwards [Line Items]
Deferred tax, operating loss carryforward	$ 1,400
Valuation allowances	5,458	$ 5,961
Deferred tax asset associated with equity method non-consolidated investee	900
U.S. federal
Operating Loss Carryforwards [Line Items]
NOL carryforwards	9,800
Valuation allowance for NOL carry-forwards not likely to be realized	6,700
State and Local Jurisdiction
Operating Loss Carryforwards [Line Items]
Tax credit carryforward	300
Valuation allowances	$ 100