Debt - Interest Expense Recognized Related to Notes Prior to Capitalization of Interest (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 28, 2019	Dec. 29, 2018
1.75% Convertible Senior Notes Due June 1, 2018
Debt Instrument [Line Items]
Contractual interest expense		$ 1,094
Amortization of debt issuance costs		402
Amortization of debt discount		4,671
Total interest expense		6,167
2.125% Convertible Senior Notes Due September 1, 2024
Debt Instrument [Line Items]
Contractual interest expense	$ 8,553	2,613
Amortization of debt issuance costs	1,149	373
Amortization of debt discount	17,612	5,716
Total interest expense	$ 27,314	$ 8,702

Amount of noncash expense included in interest expense to amortize debt discount and premium associated with the related debt instruments. Excludes amortization of financing costs. Alternate captions include noncash interest expense.

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Amount of amortization expense attributable to debt issuance costs.

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Amount of the cost of borrowed funds accounted for as interest expense for debt.

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Represents the portion of interest incurred in the period on debt arrangements that was charged against earnings, excluding amortization of debt discount (premium) and financing costs.

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