Quarterly report pursuant to Section 13 or 15(d)

Sales to Major Customers (Details)

v3.10.0.1
Sales to Major Customers (Details)
$ in Millions
3 Months Ended 6 Months Ended
Jun. 30, 2018
USD ($)
Jul. 01, 2017
Jun. 30, 2018
USD ($)
customer
Jul. 01, 2017
customer
Segment Reporting, Asset Reconciling Item        
Number of major customers | customer     2 2
Sales Revenue, Net | Customer Concentration Risk | Major Customer One        
Segment Reporting, Asset Reconciling Item        
Percent of consolidated revenue 12.00% 16.00% 16.00% 20.00%
Sales Revenue, Net | Customer Concentration Risk | Major Customer Two        
Segment Reporting, Asset Reconciling Item        
Percent of consolidated revenue 14.00% 18.00% 15.00% 18.00%
Sales Revenue, Net | Customer Concentration Risk | Two Major Customers        
Segment Reporting, Asset Reconciling Item        
Accounts receivable from major customers | $ $ 31.5   $ 31.5