Intangible Assets (Details) - USD ($)	3 Months Ended
	Mar. 30, 2019	Mar. 31, 2018	Dec. 29, 2018
Finite-Lived Intangible Assets [Line Items]
Impairment of acquired intangible assets	$ 0	$ 0
Accumulated amortization, intangible assets	117,200,000		$ 114,500,000
Amortization of acquired intangible assets	3,403,000	5,763,000
Research and development
Finite-Lived Intangible Assets [Line Items]
Amortization of acquired intangible assets	14,000	127,000
Amortization of acquired intangible assets
Finite-Lived Intangible Assets [Line Items]
Amortization of acquired intangible assets	$ 3,389,000	$ 5,636,000