Lease - Lease Information (Details) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 27, 2019 USD ($)	Sep. 27, 2019 USD ($)
Leases [Abstract]
Operating lease cost	$ 2,641	$ 6,868
Variable lease cost	837	2,360
Total lease cost	3,478	9,228
Cash paid for amounts included in the measurement of operating lease liabilities	2,655	6,937
Right-of-Use assets obtained in exchange for operating lease obligations	$ 0	$ 10,305
Weighted-average remaining lease term (years), Operating leases	7 years 2 months 12 days	7 years 2 months 12 days
Weighted-average discount rate, Operating leases	6.80%	6.80%