Share-Based Compensation - Additional Information (Detail) (USD $)	3 Months Ended
Sep. 30, 2014	Sep. 26, 2014
Deferred stock units outstanding [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate intrinsic value of stock option outstanding calculated using the closing price of common stock		$ 75.00
Shares withheld to meet statutory minimum tax withholding requirements	38,414
Shares valued withheld to meet statutory minimum tax withholding requirements	$ 2,800,000
Stock unit awards, aggregate intrinsic value	71,492,000
Stock Unit Awards, Granted	47,802
Stock unit awards, delivered	133,112
Stock unit awards, forfeited	19,704
Market stock units outstanding [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate intrinsic value of stock option outstanding calculated using the closing price of common stock		$ 75.00
Vesting period, tranche one	1 year
Vesting period, tranche two	2 years
Vesting period, tranche three	3 years
Potential payout adjustment ratio	2
Stock unit awards, aggregate intrinsic value	9,000,000
Stock Unit Awards, Granted	0
Stock unit awards, delivered	0
Stock unit awards, forfeited	0
Unrecognized share-based compensation cost	$ 3,900,000
Unrecognized share-based compensation, period for recognition	10 months 24 days
Market stock units outstanding [Member] \| Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Potential payout range	0.00%
Market stock units outstanding [Member] \| Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Potential payout range	200.00%
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate intrinsic value of stock option outstanding calculated using the closing price of common stock		$ 75.00

Percentage of potential payout.

No definition available.

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- Definition

Potential payout adjustment ratio.

+ References

No definition available.

+ Details

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Namespace Prefix:	syna_
Data Type:	xbrli:pureItemType
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- Definition

Share based compensation arrangement by share based payment award, award vesting period tranche one.

+ References

No definition available.

+ Details

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Namespace Prefix:	syna_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Share based compensation arrangement share based payment award, award vesting period tranche three.

+ References

No definition available.

+ Details

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Namespace Prefix:	syna_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Share based compensation arrangement by share based payment award award vesting period tranche two.

+ References

No definition available.

+ Details

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Namespace Prefix:	syna_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Share based compensation arrangement by share based payment award intrinsic value closing price.

+ References

No definition available.

+ Details

Name:	syna_ShareBasedCompensationArrangementByShareBasedPaymentAwardIntrinsicValueClosingPrice
Namespace Prefix:	syna_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant

- Definition

The amount of adjustment to stockholders' equity associated with an employee's income tax withholding obligation as part of a net-share settlement of a share-based award.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Weighted average period over which unrecognized compensation is expected to be recognized for equity-based compensation plans, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (i)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

+ Details

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Data Type:	xbrli:durationItemType
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Period Type:	duration

- Definition

Unrecognized cost of unvested share-based awards, other than options, awarded to employees as compensation.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Intrinsic value of equity-based compensation awards outstanding. Excludes stock and unit options.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The number of equity-based payment instruments, excluding stock (or unit) options, that were forfeited during the reporting period.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)(1)(iv)(3)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)(2)(iii)(1)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

The number of equity-based payment instruments, excluding stock (or unit) options, that vested during the reporting period.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)(2)(iii)(2)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Details

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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

For net-share settlement of share-based awards when the employer settles employees' income tax withholding obligations, this element represents the number of shares the employees use to repay the employer.

+ References

No definition available.

+ Details

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Data Type:	xbrli:sharesItemType
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Period Type:	duration