v3.26.1
Income Taxes (Narrative) (Details) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 27, 2025
Dec. 28, 2024
Operating Loss Carryforwards.    
U.S. federal statutory tax 21.00% 21.00%
Valuation allowance $ 81,786 $ 77,145
Increase (Decrease) in valuation allowance 4,600 $ 11,300
Unrecognized Tax Benefits 0  
Federal    
Operating Loss Carryforwards.    
Net operating loss carryforwards 300,300  
Net operating loss carryforwards, which will expire from 2029 through 2037 104,200  
Net operating loss carryforwards, which will be carried forward indefinitely 196,100  
Tax credit carryforwards 2,800  
State and Local Jurisdiction [Member]    
Operating Loss Carryforwards.    
Net operating loss carryforwards 106,600  
Tax credit carryforwards 2,500  
Foreign Tax Authority [Member] | State Administration of Taxation, China [Member]    
Operating Loss Carryforwards.    
Net operating loss carryforwards 500  
Net operating loss carryforwards expired $ 2,100