Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 30, 2019	Mar. 31, 2018	Dec. 29, 2018
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
Income tax expense	$ 234	$ 597
Unrecognized tax benefits that could significantly change during the next twelve months	1,200
Unrecognized tax benefits, associated interest and penalties that could significantly change within the next twelve months	100
Total potential decrease in UTB	1,300
Deferred tax assets, valuation allowance	24,900
Federal
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
Operating loss carryforwards			$ 365,300
Tax credit carryforward, amount			51,500
State and Local Jurisdiction
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
Operating loss carryforwards			147,600
Tax credit carryforward, amount			61,200
Other Long-term Liabilities
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
Uncertain tax positions	$ 25,900		26,300
No Expiration Date
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
Tax credit carryforward, amount			$ 60,200