Summary of Significant Accounting Policies - Additional Information (Detail) (USD $)	12 Months Ended
	Sep. 26, 2014 Customer Unit Segment	Sep. 27, 2013 Unit	Sep. 28, 2012 Unit
Significant Accounting Policies [Line Items]
Number of reportable operating segments	2
Foreign currency gain (loss) before tax	$ (500,000)	$ 700,000	$ 400,000
Equity investments under equity method accounting	Equity investments in privately held companies in which the Company holds at least a 20% ownership interest or in which the Company has the ability to exercise significant influence are accounted for under the equity method of accounting. Equity investments in privately held companies in which the Company holds less than a 20% ownership interest and does not have the ability to exercise significant influence are accounted for under the cost method of accounting.
Equity investments under cost method	15,000,000	21,400,000
Carrying value of equity investments in privately-held companies	49,700,000	49,700,000
Impairment loss on equity investments in privately held companies	0	0	0
Impairment of a privately-held equity investment	7,725,000
Number of customers accounted for more than 10% of total accounts receivable	0
Impairment charges for long-lived assets and identifiable assets	0	0	0
Goodwill impairment charges	0	0	0
Number of reporting units tested for impairment of goodwill	4	4	4
Costs incurred and revenues recognized in excess of customer billings	57,200,000	68,100,000
Customer billings in excess of costs incurred and revenue recognized	52,600,000	33,800,000
Excise tax on sales of medical devices, percentage	2.30%
Minimum
Significant Accounting Policies [Line Items]
Finite-lived intangible asset, useful life	2 years
Maximum
Significant Accounting Policies [Line Items]
Finite-lived intangible asset, useful life	17 years
Land Improvements
Significant Accounting Policies [Line Items]
Property, plant and equipment, useful life	15 years
Building | Minimum
Significant Accounting Policies [Line Items]
Property, plant and equipment, useful life	20 years
Building | Maximum
Significant Accounting Policies [Line Items]
Property, plant and equipment, useful life	30 years
Machinery and Equipment | Minimum
Significant Accounting Policies [Line Items]
Property, plant and equipment, useful life	3 years
Machinery and Equipment | Maximum
Significant Accounting Policies [Line Items]
Property, plant and equipment, useful life	7 years
Assets Subject To Lease
Significant Accounting Policies [Line Items]
Property, plant and equipment, estimated useful lives	the lesser of estimated useful lives or remaining lease terms
Land Leasehold Rights And Leasehold Improvements
Significant Accounting Policies [Line Items]
Property, plant and equipment, estimated useful lives	the lesser of estimated useful lives or remaining lease terms
Augmenix
Significant Accounting Policies [Line Items]
Impairment of a privately-held equity investment	$ 1,400,000