Acquired Intangibles and Goodwill - Summary of Life, Gross Carrying Value and Related Accumulated Amortization of Acquired Intangible Assets (Detail) - USD ($) $ in Millions	6 Months Ended
Dec. 31, 2018	Jun. 30, 2018
Finite-Lived Intangible Assets [Line Items]
Acquired intangibles, Gross Carrying Value	$ 445.5	$ 456.1
Acquired intangibles, Accumulated Amortization	(264.3)	(236.9)
Acquired intangibles, Net Carrying Value	$ 181.2	219.2
Weighted Average Life in Years	5 years
Display Driver Technology [Member]
Finite-Lived Intangible Assets [Line Items]
Acquired intangibles, Gross Carrying Value	$ 164.0	164.0
Acquired intangibles, Accumulated Amortization	(132.2)	(116.5)
Acquired intangibles, Net Carrying Value	$ 31.8	47.5
Weighted Average Life in Years	5 years 3 months 18 days
Audio and Video Technology [Member]
Finite-Lived Intangible Assets [Line Items]
Acquired intangibles, Gross Carrying Value	$ 134.1	133.9
Acquired intangibles, Accumulated Amortization	(35.9)	(22.8)
Acquired intangibles, Net Carrying Value	$ 98.2	111.1
Weighted Average Life in Years	5 years 6 months
Fingerprint Authentication Technology [Member]
Finite-Lived Intangible Assets [Line Items]
Acquired intangibles, Gross Carrying Value	$ 47.2	55.7
Acquired intangibles, Accumulated Amortization	$ (47.2)	(53.7)
Acquired intangibles, Net Carrying Value		2.0
Weighted Average Life in Years	4 years 8 months 12 days
Customer Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Acquired intangibles, Gross Carrying Value	$ 81.8	81.8
Acquired intangibles, Accumulated Amortization	(44.2)	(38.5)
Acquired intangibles, Net Carrying Value	$ 37.6	43.3
Weighted Average Life in Years	4 years 1 month 6 days
Licensed Technology and Other [Member]
Finite-Lived Intangible Assets [Line Items]
Acquired intangibles, Gross Carrying Value	$ 7.7	9.0
Acquired intangibles, Accumulated Amortization	(2.6)	(3.0)
Acquired intangibles, Net Carrying Value	$ 5.1	6.0
Weighted Average Life in Years	4 years 2 months 12 days
Tradename [Member]
Finite-Lived Intangible Assets [Line Items]
Acquired intangibles, Gross Carrying Value	$ 1.8	1.9
Acquired intangibles, Accumulated Amortization	(0.4)	(0.2)
Acquired intangibles, Net Carrying Value	$ 1.4	1.7
Weighted Average Life in Years	7 years
Patents [Member]
Finite-Lived Intangible Assets [Line Items]
Acquired intangibles, Gross Carrying Value	$ 4.4	4.6
Acquired intangibles, Accumulated Amortization	(1.8)	(1.7)
Acquired intangibles, Net Carrying Value	$ 2.6	2.9
Weighted Average Life in Years	8 years 1 month 6 days
Backlog [Member]
Finite-Lived Intangible Assets [Line Items]
Acquired intangibles, Gross Carrying Value		0.5
Acquired intangibles, Accumulated Amortization		(0.5)
In-Process Research and Development [Member]
Finite-Lived Intangible Assets [Line Items]
Acquired intangibles, Gross Carrying Value	$ 4.5	4.7
Acquired intangibles, Net Carrying Value	$ 4.5	$ 4.7

Weighted average amortization period of finite-lived intangible assets acquired either individually or as part of a group of assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 30
-Section 50
-Paragraph 1
-Subparagraph (a)(3)
-URI http://asc.fasb.org/extlink&oid=66006027&loc=d3e16265-109275

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Accumulated amount of amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 30
-Section 50
-Paragraph 2
-Subparagraph (a)(1)
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Amount before amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 928
-SubTopic 340
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6473545&loc=d3e61844-108004

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Amount after amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

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