Income Taxes (Narrative) (Details) - USD ($) $ in Millions |
12 Months Ended | ||
---|---|---|---|
Dec. 29, 2017 |
Dec. 30, 2016 |
Jan. 01, 2016 |
|
Income Tax Examination [Line Items] | |||
Tax Cuts and Jobs Act of 2017, reduction in deferred tax asset | $ 184.8 | ||
Tax Cuts and Jobs Act of 2017, change in valuation allowance | 184.8 | ||
Valuation allowance increase (decrease) | (210.1) | $ 92.7 | $ 7.9 |
Federal [Member] | |||
Income Tax Examination [Line Items] | |||
Net operating loss carryforwards | 1,105.0 | ||
Research and development tax credits | 83.0 | ||
State and Local Jurisdiction [Member] | |||
Income Tax Examination [Line Items] | |||
Net operating loss carryforwards | 424.0 | ||
State and Local Jurisdiction [Member] | Research Tax Credit Carryforward [Member] | |||
Income Tax Examination [Line Items] | |||
Research and development tax credits | $ 28.0 |