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Income taxes (Schedule of Deferred Tax Assets and (Liabilities)) (Details) (USD $)
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Dec. 31, 2013
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Dec. 31, 2012
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| Income taxes [Abstract] | ||
| Net operating loss carry forwards | $ 29,494,000 | $ 25,100,000 |
| Property and equipment | 37,000 | 32,000 |
| Patents and other intangible assets | 14,000 | 17,000 |
| Other | (12,000) | |
| Difference revenue | (39,000) | 551,000 |
| Research and development credit | 991,000 | 753,000 |
| Deferred tax asset | 30,485,000 | 26,453,000 |
| Valuation allowance | (30,485,000) | (26,453,000) |
| Deferred tax assets (liabilities) |
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- Definition
Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences from deferred income. 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 intangible assets including goodwill. 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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- 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 temporary differences from property, plant, and equipment. No definition available.
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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 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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- Details
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