Name:	slab_IncomeTaxesLineItems
Namespace Prefix:	slab_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Amount of income tax expense (benefit) from change in tax rate pursuant to Tax Cuts and Jobs Act of 2017.

No definition available.

Name:	slab_TaxCutsAndJobsActOf2017ChangeInTaxRateIncomeTaxExpenseBenefit
Namespace Prefix:	slab_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Amount of reasonable estimate for income tax expense (benefit) from effect of Tax Cuts and Jobs Act of 2017 for which accounting for tax effect is incomplete.

No definition available.

Name:	slab_TaxCutsAndJobsActOf2017IncomeTaxExpenseBenefitIncompleteAccountingProvisionalAmount
Namespace Prefix:	slab_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Amount of reasonable estimate for income tax expense (benefit) from transition tax on accumulated earnings of controlled foreign corporation deemed repatriated pursuant to Tax Cuts and Jobs Act of 2017 for which accounting for tax effect is incomplete.

No definition available.

Name:	slab_TaxCutsAndJobsActOf2017TransitionTaxForAccumulatedForeignEarningsIncomeTaxExpenseBenefitIncompleteAccountingProvisionalAmount
Namespace Prefix:	slab_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

The holding period required for foreign corporations owned by U.S. corporate shareholders in order to qualify for the dividends received deduction under the TCJA.

No definition available.

Name:	slab_TcjaDividendsReceivedDeductionHoldingPeriodForForeignCorporations
Namespace Prefix:	slab_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

The ownership percentage of foreign corporations by U.S. corporate shareholders which is a threshold for qualifying for the dividends received deduction under the TCJA.

No definition available.

Name:	slab_TcjaDividendsReceivedDeductionOwnershipPercentageApplicableToForeignCorporationsOwnedByUsShareholders
Namespace Prefix:	slab_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

The percentage of dividend received from 10% owned foreign corporations by U.S. corporate shareholders that may be deducted under the TCJA.

No definition available.

Name:	slab_TcjaDividendsReceivedDeductionPercentageApplicableToForeignCorporationsOwnedByUsShareholders
Namespace Prefix:	slab_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

Amount of income tax expense (benefit) due to the write off of deferred tax asset (liability) associated with the dividends received deduction provision of the TCJA.

No definition available.

Name:	slab_TcjaDividendsReceivedDeductionWriteoffOfDeferredTaxAssetLiability
Namespace Prefix:	slab_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Amount of reasonable estimate for the increase (decrease) in the valuation allowance for deferred tax assets as a result of the TCJA.

No definition available.

Name:	slab_TcjaIncomeTaxReconciliationChangeInDeferredTaxAssetsValuationAllowanceIncompleteAccountingProvisionalamount
Namespace Prefix:	slab_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Period of time over which TCJA transition tax on certain unrepatriated earnings of foreign subsidiaries may be paid.

No definition available.

Name:	slab_TcjaTransitionTaxPeriodForPayment
Namespace Prefix:	slab_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

Percentage of domestic federal statutory tax rate applicable to pretax income (loss).

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 12
-URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32687-109319

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB TOPIC 6.I)
-URI http://asc.fasb.org/extlink&oid=34349781&loc=d3e330036-122817

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 13
-URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32698-109319