Cash, Cash Equivalents and Restricted Cash - (Details) - USD ($)
$ in Thousands
Jun. 27, 2020
Dec. 31, 2019
Jun. 29, 2019
Dec. 31, 2018
Cash and Cash Equivalents [Line Items]        
Total cash and cash equivalents $ 50,552 $ 46,829    
Restricted cash 628 628    
Total cash 51,180 47,457 $ 35,570 $ 50,274
Cash        
Cash and Cash Equivalents [Line Items]        
Total cash and cash equivalents 50,552 46,815    
Money market funds        
Cash and Cash Equivalents [Line Items]        
Total cash and cash equivalents $ 0 $ 14