Amounts Recognized in Consolidated Financial Statements of Operations with Respect to Stock Based Compensation Plan (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 28, 2020	Sep. 30, 2019	Sep. 28, 2020	Sep. 30, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense recognized	$ 4,479	$ 4,662	$ 11,961	$ 12,190
Cost of goods sold
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense recognized	1,173	937	2,643	2,210
Selling and marketing
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense recognized	557	574	1,299	1,408
General and administrative
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense recognized	2,705	3,089	7,872	8,421
Research and development
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense recognized	$ 44	$ 62	$ 147	$ 151