Quarterly report pursuant to Section 13 or 15(d)

Legal Proceedings (Details)

v3.20.2
Legal Proceedings (Details)
 1 Months Ended 3 Months Ended 9 Months Ended 12 Months Ended
Apr. 11, 2018
USD ($)
Aug. 31, 2020
USD ($)
Sep. 26, 2020
USD ($)
Sep. 28, 2019
USD ($)
Sep. 26, 2020
USD ($)
Sep. 28, 2019
USD ($)
Dec. 31, 2019
USD ($)
Sep. 07, 2020
USD ($)
Jul. 31, 2020
USD ($)
Dec. 31, 2018
USD ($)
Loss Contingencies [Line Items]                    
Non-cash litigation settlement         $ 0 $ (1,700,000)        
Lufthansa Technik AG | AES                    
Loss Contingencies [Line Items]                    
Loss contingency, claim of loss                 $ 50,000  
Loss contingency, estimate of possible loss               $ 25,000    
Loss contingency, damages paid, value   $ 1,300,000                
Germany | Lufthansa Technik AG | Patent Infringement | AES                    
Loss Contingencies [Line Items]                    
Damages sought $ 6,200,000                  
Litigation settlement, amount awarded to other party, excluding interest             $ 3,200,000      
Loss contingency accrual             4,500,000     $ 1,000,000.0
Loss contingency accrual, incremental reserve       $ 1,700,000   $ 1,700,000 3,500,000      
Litigation settlement, amount awarded to other party         $ 4,700,000          
Germany | Indirect Sales | Patent Infringement | AES                    
Loss Contingencies [Line Items]                    
Estimate of possible loss, excluding interest             11,600,000      
Interest rate accrued above bank rate until final payment         0.05          
Non-cash litigation settlement         $ 16,500,000   $ 16,100,000      
Germany | Indirect Sales | Patent Infringement | AES | Selling, General and Administrative                    
Loss Contingencies [Line Items]                    
Litigation settlement interest     $ 100,000   $ 400,000