| Income Taxes Income Taxes - Components of Deferred Income Tax Assets (Details) (USD $) In Thousands, unless otherwise specified | Dec. 31, 2014 | Dec. 31, 2013 | 
|---|---|---|
| Deferred Tax Assets, Net [Abstract] | ||
| Net operating loss carryforwards | $ 9,924us-gaap_DeferredTaxAssetsOperatingLossCarryforwards | $ 8,545us-gaap_DeferredTaxAssetsOperatingLossCarryforwards | 
| Research and development credits | 12,783us-gaap_DeferredTaxAssetsTaxCreditCarryforwardsResearch | 12,718us-gaap_DeferredTaxAssetsTaxCreditCarryforwardsResearch | 
| Accrued expenses and other | 1,044us-gaap_DeferredTaxAssetsOther | 476us-gaap_DeferredTaxAssetsOther | 
| Employee compensation | 994us-gaap_DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsEmployeeCompensation | 1,686us-gaap_DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsEmployeeCompensation | 
| Stock-Based compensation | 4,516us-gaap_DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsShareBasedCompensationCost | 2,732us-gaap_DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsShareBasedCompensationCost | 
| Deferred tax assets, depreciation and amortization | 250mxl_Deferredtaxassetsdepreciationandamortization | 2,637mxl_Deferredtaxassetsdepreciationandamortization | 
| Deferred tax assets, gross | 29,511us-gaap_DeferredTaxAssetsGross | 28,794us-gaap_DeferredTaxAssetsGross | 
| Less valuation allowance | (29,399)us-gaap_DeferredTaxAssetsValuationAllowance | (28,628)us-gaap_DeferredTaxAssetsValuationAllowance | 
| Deferred Tax Assets, Net | $ 112us-gaap_DeferredTaxAssetsLiabilitiesNet | $ 166us-gaap_DeferredTaxAssetsLiabilitiesNet | 
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- Definition Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences from depreciation and amortization. No definition available. 
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- Definition Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences and carryforwards. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Definition Amount after allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences and carryforwards, net of deferred tax liability attributable to taxable temporary differences. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Details 
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- Definition Amount before allocation of valuation allowances of deferred tax asset attributable to deductible operating loss carryforwards. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Definition Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences not separately disclosed. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Definition Amount before allocation of valuation allowances of deferred tax asset attributable to deductible research tax credit carryforwards. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Definition Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences from employee compensation. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Definition Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences from share-based compensation. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Definition Amount of deferred tax assets for which it is more likely than not that a tax benefit will not be realized. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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