Balance Sheet Details - Accounts Receivable and Unbilled Receivables (Details) - USD ($) $ in Millions	Dec. 26, 2021	Dec. 27, 2020
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total current accounts receivable	$ 285.1	$ 274.1
Allowance for doubtful accounts	(0.4)	(1.8)
Total accounts receivable and unbilled receivables, net	284.7	272.3
U.S. Government
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total U.S. Government contract receivables	104.9	97.4
Billed
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total current accounts receivable	94.2	97.0
Billed | U.S. Government
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total U.S. Government contract receivables	11.3	19.5
Unbilled
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total current accounts receivable	190.9	177.1
Unbilled | U.S. Government
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total U.S. Government contract receivables	$ 93.6	$ 77.9