Commitments and Contingencies - Facility and Equipment Leases (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 27, 2020	Sep. 29, 2019	Sep. 27, 2020		Sep. 29, 2019
Loss Contingencies [Line Items]
Operating lease expense	$ 3,524	$ 2,700	$ 10,458		$ 7,890
Sublease income (expense)	(111)	(20)	(166)		(330)
Rent expense	3,413	2,680	10,292		7,560
Operating cash flows for operating leases1	7,117	2,849	14,314		11,411
Right-of-use assets obtained in exchange for lease obligations	$ 8,362	$ 8,939	$ 21,786	[1]	$ 103,744	[1]
Weighted-average remaining lease term (in years) - operating leases	7 years 6 months	7 years	7 years 6 months		7 years
Weighted-average discount rate - operating leases	9.00%	9.00%	9.00%		9.00%
Minimum
Loss Contingencies [Line Items]
Lessee, operating lease, renewal term	1 year		1 year
Maximum
Loss Contingencies [Line Items]
Lessee, operating lease, renewal term	10 years		10 years

[1] Amounts for the nine months ended September 29, 2019 include the transition adjustment for the adoption of Accounting Standards Update ("ASU") No. 2016-02, Leases (Topic 842), as amended ("ASC 842") and additional Right-of-Use ("ROU") asset additions.