Fair Value of Financial Instruments (Details 2) (Auction rate securities, Weighted Average, Discounted cash flow)	6 Months Ended
Jun. 30, 2012
Auction rate securities \| Weighted Average \| Discounted cash flow
Quantitative information for Level 3 Fair Value Measurements Assets
Estimated yield (as a percent)	1.06%
Expected holding period	10 years
Estimated discount rate (as a percent)	2.92%

Represents the expected holding period, used as an input to measure fair value.

No definition available.

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