Income Taxes - Net Deferred Tax Assets and Deferred Tax Liabilities (Details) (USD $) In Thousands, unless otherwise specified	Jan. 25, 2015	Jan. 26, 2014
Deferred tax assets
Current	$ 2,478us-gaap_DeferredTaxAssetsNetCurrent	$ 2,946us-gaap_DeferredTaxAssetsNetCurrent
Non-current	106us-gaap_DeferredTaxAssetsNetNoncurrent	348us-gaap_DeferredTaxAssetsNetNoncurrent
Subtotal	2,584us-gaap_DeferredTaxAssetsNet	3,294us-gaap_DeferredTaxAssetsNet
Deferred tax liabilities
Current	(1,444)us-gaap_DeferredTaxLiabilitiesCurrent	(930)us-gaap_DeferredTaxLiabilitiesCurrent
Non-current	(2,477)	(3,626)
Subtotal	(3,921)smtc_DeferredTaxLiabilitiesNetTotal	(4,556)smtc_DeferredTaxLiabilitiesNetTotal
Net deferred tax liabilities	$ (1,337)us-gaap_DeferredTaxLiabilities	$ (1,262)us-gaap_DeferredTaxLiabilities

Deferred Tax Liabilities, Net, Total

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Amount after allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences and carryforwards.

+ References

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-Publisher FASB

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Amount after allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences and carryforwards expected to be realized or consumed within one year or operating cycle, if longer.

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Amount after allocation of valuation allowances of noncurrent deferred tax asset attributable to deductible temporary differences and carryforwards. Noncurrent assets are expected to be realized or consumed after one year (or the normal operating cycle, if longer).

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Amount of deferred tax liability attributable to taxable temporary differences net of deferred tax asset attributable to deductible temporary differences and carryforwards after valuation allowances.

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Amount of deferred tax liability attributable to taxable temporary differences, net of deferred tax asset attributable to deductible temporary differences and carryforwards net of valuation allowances expected to be realized or consumed within one year or operating cycle, if longer.

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