Acquisitions - Summary of Estimated Fair Values of Assets Acquired and Liabilities Assumed (Detail) - USD ($) $ in Millions	Jun. 30, 2018	Sep. 08, 2017	Jul. 25, 2017	Jun. 24, 2017	Jun. 25, 2016
Business Acquisition [Line Items]
Goodwill	$ 372.8			$ 206.8	$ 206.8
Conexant Systems, LLC [Member]
Business Acquisition [Line Items]
Cash			$ 4.3
Accounts receivable			11.7
Inventory			51.0
Other current assets			3.5
Property and equipment			3.2
Acquired intangible assets			145.7
Other assets			0.9
Total identifiable assets acquired			220.3
Accounts payable			14.2
Accrued compensation			1.3
Other accrued liabilities			9.3
Other long-term liabilities			3.0
Net identifiable assets acquired			192.5
Goodwill			153.7
Net assets acquired			$ 346.2
Marvell Technology Group Ltd [Member]
Business Acquisition [Line Items]
Inventory		$ 28.4
Property and equipment		5.0
Acquired intangible assets		48.7
Total identifiable assets acquired		82.1
Accrued liabilities		0.7
Net identifiable assets acquired		81.4
Goodwill		12.3
Net assets acquired		$ 93.7