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Debt - Carrying amount of Notes (Details) - 1.375% Convertible Senior Notes - USD ($)
$ in Thousands
12 Months Ended
Dec. 28, 2019
Dec. 29, 2018
Liability component    
Principal $ 400,000 $ 400,000
Unamortized debt discount (27,580) (39,298)
Unamortized debt issuance costs (4,163) (5,931)
Net carrying amount 368,257 354,771
Equity component    
Net carrying amount $ 57,735 $ 57,735
Effective interest rate 4.75%  
Amortization period of debt discount and debt issuance costs 2 years 2 months 12 days