Balance Sheet Details (Tables)

12 Months Ended

Dec. 27, 2020

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Schedule of Accounts, Notes, Loans and Financing Receivable

Receivables including amounts due under long-term contracts are summarized as follows (in millions):

	December 27, 2020		December 29, 2019
Billed, current	$	97.0	$	86.6
Unbilled, current	177.1		179.7
Total current accounts receivable	274.1		266.3
Allowance for doubtful accounts	(1.8)		(1.9)
Total accounts receivable and unbilled receivables, net	$	272.3	$	264.4

U.S. Government contract receivables where the Company is the prime contractor included in accounts receivable, net (in millions):

	December 27, 2020		December 29, 2019
Billed	$	19.5	$	16.6
Unbilled	77.9		86.4
Total U.S. Government contract receivables	$	97.4	$	103.0

Schedule of Inventory

Inventoried costs (in millions): 

	December 27, 2020		December 29, 2019
Raw materials	$	47.3	$	39.1
Work in process	30.1		20.3
Finished goods	3.8		1.7
Total inventoried costs	$	81.2	$	61.1

Property, Plant and Equipment

Assets are depreciated predominately using the straight-line method, with the following lives:

	Years
Buildings and improvements	15 – 39
Machinery and equipment	3 – 20
Computer equipment and software	1 – 10
Vehicles, furniture, and office equipment	5
Leasehold improvements	Shorter of useful life or length of lease

Property, plant and equipment, net (in millions)

	December 27, 2020		December 29, 2019
Finance lease right of use assets	$	40.6	$	39.6
Land and buildings	$	19.1	$	12.2
Computer equipment and software	37.0		32.7
Machinery and equipment	105.3		78.7
Furniture and office equipment	7.9		7.1
Leasehold improvements	15.0		12.3
Construction in progress	18.2		16.0
Property and equipment	243.1		198.6
Accumulated depreciation and amortization	(99.3)		(81.7)
Total property and equipment, net	$	143.8	$	116.9