Quarterly report pursuant to Section 13 or 15(d)

Summary of Significant Accounting Policies (Details Textual)

v3.19.2
Summary of Significant Accounting Policies (Details Textual) - USD ($)
$ in Thousands
6 Months Ended
Jun. 29, 2019
Jun. 30, 2018
Dec. 31, 2018
Dec. 29, 2018
Summary of Significant Accounting Policies [Line Items]        
Operating lease, right-of-use assets $ 13,592      
Operating lease, right-of-use liabilities 13,734      
Contract asset, current 1,956     $ 2,851
Contract Liabilities, current 451     $ 138
Research and development costs charged to expense $ 7,778 $ 6,301    
Accounting Standards Update 2016-02 [Member]        
Summary of Significant Accounting Policies [Line Items]        
Operating lease, right-of-use assets     $ 13,918  
Operating lease, right-of-use liabilities     13,918  
Cumulative-effect adjustment recognized in retained earnings     $ 134