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Income Taxes (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
Income Taxes (Narrative) (Details) - USD ($) $ in Thousands	Dec. 28, 2018	Dec. 29, 2017	Dec. 30, 2016	Jan. 01, 2016
Income Tax Disclosure [Abstract]
Deferred tax assets	$ 244,111	$ 0
Valuation allowance	58,112	418,958
Valuation allowance increase (decrease)	(360,800)	(210,100)
Income Tax Examination [Line Items]
Unrecognized tax benefits	76,060	79,342	$ 61,809	$ 88,638
Unrecognized tax benefits that would reduce income tax provision and effective tax rate	$ 46,000
Federal [Member]
Income Tax Examination [Line Items]
Net operating loss carryforwards		614,000
Research and development tax credits		102,000
State and Local Jurisdiction [Member]
Income Tax Examination [Line Items]
Net operating loss carryforwards		453,000
State and Local Jurisdiction [Member] \| Research Tax Credit Carryforward [Member]
Income Tax Examination [Line Items]
Research and development tax credits		$ 34,000