Employee Benefit Plans (Schedule of Total Stock-Based Compensation Expense Resulting from Stock Options, Restricted Stock Awards, and the Employee Stock Purchase Plan) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Oct. 01, 2017	Sep. 30, 2018	Oct. 01, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation	$ 9,554	$ 5,583	$ 26,674	$ 16,412
Cost of revenue
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation	853	499	2,571	1,477
Research and development
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation	1,907	1,056	5,431	3,748
Sales and marketing
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation	2,728	1,654	7,847	4,339
General and administrative
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation	$ 4,066	$ 2,374	$ 10,825	$ 6,848