Percentage of potential payout.

No definition available.

Name:	syna_PercentageOfPotentialPayout
Namespace Prefix:	syna_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Potential payout adjustment ratio.

+ References

No definition available.

+ Details

Name:	syna_PotentialPayoutAdjustmentRatio
Namespace Prefix:	syna_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	duration

- Definition

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

+ References

No definition available.

+ Details

Name:	syna_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriodTrancheOne
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

Name:	syna_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriodTrancheThree
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

Name:	syna_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriodTrancheTwo
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

Name:	us-gaap_AdjustmentsRelatedToTaxWithholdingForShareBasedCompensation
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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Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

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

+ References

No definition available.

+ Details

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

- 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

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

- Details

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Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_AwardTypeAxis=syna_MarketStockUnitsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_AwardTypeAxis=us-gaap_EmployeeStockOptionMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Share-Based Compensation - Additional Information (Detail) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended	6 Months Ended
	Dec. 31, 2014	Dec. 31, 2014	Dec. 26, 2014
Employee Stock Option [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			$ 71.80
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			$ 71.80
Shares withheld to meet statutory minimum tax withholding requirements		74,568
Shares valued withheld to meet statutory minimum tax withholding requirements		$ 5.2
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			$ 71.80
Shares withheld to meet statutory minimum tax withholding requirements		47,883
Shares valued withheld to meet statutory minimum tax withholding requirements		3.0
Vesting period, tranche one		1 year
Vesting period, tranche two		2 years
Vesting period, tranche three		3 years
Potential payout adjustment ratio		2
Unrecognized share-based compensation cost	$ 7.7	$ 7.7
Unrecognized share-based compensation, period for recognition	1 year 5 months 9 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%
Market Stock Units Outstanding [Member] \| Maximum [Member] \| Share-based Compensation Award, Tranche One [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Potential payout range		100.00%
Market Stock Units Outstanding [Member] \| Maximum [Member] \| Share-based Compensation Award, Tranche Two [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Potential payout range		100.00%