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Non-current Other Assets - Additional Information (Detail) (USD $)	9 Months Ended
	Mar. 31, 2015
Schedule of Available-for-sale Securities [Line Items]
Proceeds from sales of non-current investments	$ 4,900,000us-gaap_ProceedsFromSaleMaturityAndCollectionsOfInvestments
Auction Rate Securities with fair value maturing from 2016 to 2018	12,800,000syna_AuctionRateSecuritiesWithFairValueMaturingWithinSpecifiedPeriod
Auction Rate Securities with fair value having no stated maturity	2,800,000syna_AuctionRateSecuritiesWithFairValueHavingNoStatedMaturity
ARS investments, investment grade	600,000syna_AuctionRateSecuritiesAtInvestmentGrade
ARS investments, below investment grade	18,500,000syna_AuctionRateSecuritiesBelowInvestmentGrade
Minimum [Member]
Schedule of Available-for-sale Securities [Line Items]
Maturity period one	2016
Maximum [Member]
Schedule of Available-for-sale Securities [Line Items]
Maturity period one	2018
Auction Rate Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Proceeds from sales of non-current investments	$ 4,900,000us-gaap_ProceedsFromSaleMaturityAndCollectionsOfInvestments / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_AuctionRateSecuritiesMember

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- Definition

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- Definition

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- Definition

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- Definition

The cash inflow associated with the sale, maturity and collection of all investments such as debt, security and so forth during the period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 12

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3179-108585



Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Investing Activities

-URI http://asc.fasb.org/extlink&oid=6516133

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