Summary of Significant Accounting Policies - Estimated Useful Lives of Property, Plant and Equipments (Detail) - USD ($)			3 Months Ended			12 Months Ended
	Oct. 15, 2020	Sep. 28, 2020	Sep. 30, 2023	Jul. 01, 2023	Apr. 01, 2023	Sep. 30, 2023	Sep. 24, 2022	Sep. 25, 2021
Property, Plant and Equipment [Line Items]
Manufacturing Equipment And Software			$ 380,000,000.0			$ 380,000,000.0	$ 394,800,000
Equipment Under Customer Usage Agreements			508,100,000			508,100,000	486,500,000
Buildings and Improvements, Gross			230,000,000.0			230,000,000.0	196,000,000.0
Leasehold Improvements, Gross			44,400,000			44,400,000	44,800,000
Land			41,100,000			41,100,000	40,900,000
Furniture and Fixtures, Gross			19,200,000			19,200,000	16,700,000
Finance Lease, Right-of-Use Asset			8,200,000			8,200,000	7,500,000
Property, Plant and Equipment, Gross			1,231,000,000			1,231,000,000	1,187,200,000
Less - accumulated depreciation and amortization			(714,000,000.0)			(714,000,000.0)	(705,600,000)
Property, plant and equipment, net			517,000,000.0			517,000,000.0	481,600,000	$ 564,700,000
Grants received from Department of defense	$ 119,300,000	$ 7,600,000
Department of defense funds received							75,000,000	21,500,000
Department of Defense funds received, not capitalized						7,600,000	1,300,000
Proceeds received from government grants for capacity expansion					$ 20,500,000	$ 20,500,000	$ 75,000,000.0	$ 21,500,000
Impairment charge				$ 186,900,000
Property, Plant and Equipment [Member] | Mobidiag
Property, Plant and Equipment [Line Items]
Impairment charge			12,100,000
Property, Plant and Equipment [Member] | ultrasound imaging assets
Property, Plant and Equipment [Line Items]
Impairment charge			$ 5,800,000
Equipment and Software [Member] | Minimum
Property, Plant and Equipment [Line Items]
Property, plant and equipment, estimated useful life			3 years			3 years
Equipment and Software [Member] | Maximum
Property, Plant and Equipment [Line Items]
Property, plant and equipment, estimated useful life			10 years			10 years
Equipment Under Customer Usage Agreements [Member] | Minimum
Property, Plant and Equipment [Line Items]
Property, plant and equipment, estimated useful life			3 years			3 years
Equipment Under Customer Usage Agreements [Member] | Maximum
Property, Plant and Equipment [Line Items]
Property, plant and equipment, estimated useful life			8 years			8 years
Building and Improvements [Member] | Minimum
Property, Plant and Equipment [Line Items]
Property, plant and equipment, estimated useful life			20 years			20 years
Building and Improvements [Member] | Maximum
Property, Plant and Equipment [Line Items]
Property, plant and equipment, estimated useful life			35 years			35 years
Furniture and Fixtures [Member] | Minimum
Property, Plant and Equipment [Line Items]
Property, plant and equipment, estimated useful life			5 years			5 years
Furniture and Fixtures [Member] | Maximum
Property, Plant and Equipment [Line Items]
Property, plant and equipment, estimated useful life			7 years			7 years