Intangible Assets (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 29, 2019	Jun. 30, 2018	Jun. 29, 2019	Jun. 30, 2018	Dec. 29, 2018
Finite-Lived Intangible Assets [Line Items]
Accumulated amortization, intangible assets	$ 120,600		$ 120,600		$ 114,500
Amortization of acquired intangible assets	3,403	$ 4,646	6,806	$ 10,409
Amortization of impairment charge relating to intangible assets	0	11,900	0	11,900
Research and development
Finite-Lived Intangible Assets [Line Items]
Amortization of acquired intangible assets	13	123	27	250
Amortization of acquired intangible assets
Finite-Lived Intangible Assets [Line Items]
Amortization of acquired intangible assets	$ 3,390	$ 4,523	$ 6,779	$ 10,159