Commitments and Contingencies - Commitments (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Jan. 02, 2020
Purchase and Capital commitments
Purchase commitment	$ 123,383
Amgen, Inc
Purchase and Capital commitments
Maximum cash and development services commitment	1,250	$ 1,250,000
Remaining portion of development funding cap	1,019,009
Minimum Purchase Commitments For Supply Purchased
Purchase and Capital commitments
Purchase commitment	101,236
Inventories
Purchase and Capital commitments
Purchase commitment	22,147
Capital Addition Purchase Commitments
Purchase and Capital commitments
Purchase commitment	$ 44,972