Employee Stock Plans - Stock-Based Compensation Expense Included in Condensed Consolidated Statements of Operations (Detail) - USD ($) $ in Millions		3 Months Ended
		Mar. 26, 2021	Mar. 26, 2021	Mar. 27, 2020
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation		$ 3.5	$ 3.5	$ 3.1
Income tax benefit			(0.8)	(0.9)
Stock-based compensation expense, net of tax			2.7	2.2
Cost of Revenues [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation	[1]		0.5	0.4
Research and Development [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation			0.1	0.1
Sales and Marketing [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation			0.3	0.3
General and Administrative [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation			$ 2.6	$ 2.3

[1] Stock-based compensation expense capitalized in inventory for the three months ended March 26, 2021 and March 27, 2020 was not significant.