Components of Intangible Assets and Their Estimated Useful Lives at Acquisition Date (Detail) - Mobile Industrial Robots (MiR) - USD ($) $ in Thousands		6 Months Ended
	Apr. 25, 2018	Jul. 01, 2018
Business Acquisition [Line Items]
Total intangible assets, fair value	$ 79,660	$ 79,700
Total intangible assets, estimated useful life, years	7 years 4 months 24 days
Developed technology
Business Acquisition [Line Items]
Total intangible assets, fair value	$ 63,820
Total intangible assets, estimated useful life, years	7 years
Trademarks and tradenames
Business Acquisition [Line Items]
Total intangible assets, fair value	$ 12,060
Total intangible assets, estimated useful life, years	11 years
Customer Relationships
Business Acquisition [Line Items]
Total intangible assets, fair value	$ 3,770
Total intangible assets, estimated useful life, years	2 years 6 months
Customer backlog
Business Acquisition [Line Items]
Total intangible assets, fair value	$ 10
Total intangible assets, estimated useful life, years	2 months 12 days