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Income taxes - deferred tax components (Details) (USD $)
In Thousands, unless otherwise specified |
Dec. 31, 2014
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Dec. 31, 2013
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Dec. 31, 2012
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| Income Tax Disclosure [Abstract] | |||
| Deferred tax assets | $ 8,074us-gaap_DeferredTaxAssetsGross | $ 8,337us-gaap_DeferredTaxAssetsGross | $ 14,301us-gaap_DeferredTaxAssetsGross |
| Net operating loss carry forwards | 42,251us-gaap_DeferredTaxAssetsOperatingLossCarryforwards | 39,432us-gaap_DeferredTaxAssetsOperatingLossCarryforwards | 24,579us-gaap_DeferredTaxAssetsOperatingLossCarryforwards |
| Less: valuation allowance | (50,325)us-gaap_DeferredTaxAssetsValuationAllowance | (47,769)us-gaap_DeferredTaxAssetsValuationAllowance | (38,880)us-gaap_DeferredTaxAssetsValuationAllowance |
| Mineral properties | 3,345us-gaap_DeferredTaxLiabilitiesPropertyPlantAndEquipment | 3,345us-gaap_DeferredTaxLiabilitiesPropertyPlantAndEquipment | |
| Net deferred tax liability | $ 3,345us-gaap_DeferredTaxAssetsLiabilitiesNet | $ 3,345us-gaap_DeferredTaxAssetsLiabilitiesNet |
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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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- 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 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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- Definition
Amount of deferred tax liability attributable to taxable temporary differences from property, plant, and equipment. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Details
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