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Commitments and contingencies (Capital Lease Obligations) (Details) (USD $)
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Sep. 30, 2013
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Dec. 31, 2012
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Dec. 31, 2011
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Dec. 31, 2008
Equipment [Member]
One LA [Member]
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Dec. 31, 2012
Equipment [Member]
Bridge [Member]
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Dec. 31, 2011
Equipment [Member]
Bridge [Member]
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| Capital Leased Assets [Line Items] | ||||||
| Capital lease obligations | $ 250,000 | $ 200,000 | ||||
| Accumulated depreciation | $ 18,471,452 | $ 16,769,324 | $ 9,407,503 | $ 193,333 | $ 153,333 |
| X | ||||||||||
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- Definition
Amount of accumulated depreciation, depletion and amortization for physical assets used in the normal conduct of business to produce goods and services. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
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- Definition
Amount before accumulated depreciation of leased physical assets used in the normal conduct of business to produce goods and services. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Details
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