Stock-Based Compensation (Stock-based Compensation Expense) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 28, 2019	Sep. 29, 2018	Sep. 28, 2019	Sep. 29, 2018
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation	$ 5,680	$ 2,708	$ 13,335	$ 9,908
Cost of products sold
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation	453	219	982	652
Research and development
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation	1,658	926	4,029	2,970
Selling, general, and administrative
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation	$ 3,569	$ 1,563	$ 8,324	$ 6,286