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Commitments and contingencies (Details) (USD $)
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6 Months Ended | 12 Months Ended | |||||||
|---|---|---|---|---|---|---|---|---|---|
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Jun. 30, 2013
Office space and warehouse facilities
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Jun. 30, 2012
Office space and warehouse facilities
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Dec. 31, 2012
Office space and warehouse facilities
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Dec. 31, 2011
Office space and warehouse facilities
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Dec. 31, 2010
Office space and warehouse facilities
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Dec. 31, 2012
Service vehicle
Number
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Dec. 31, 2011
Service vehicle
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Dec. 31, 2010
Service vehicle
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Jan. 31, 2012
Service vehicle
Number
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| Operating Leased Assets [Line Items] | |||||||||
| Rent expense, gross | $ 244,153 | $ 97,174 | $ 595,851 | $ 579,836 | $ 535,092 | ||||
| Rent expense, sublease rent offset | 173,898 | 185,596 | 196,466 | ||||||
| Rent expense, net | $ 421,953 | $ 394,240 | $ 338,626 | $ 387 | $ 4,639 | $ 4,639 | |||
| Number of operating leased assets | 1 | 1 | |||||||
| X | ||||||||||
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- Definition
Operating Leased Assets, Number of Assets No definition available.
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| X | ||||||||||
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- Details
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| X | ||||||||||
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- Definition
This element represents the payments that the lessee is obligated to make or can be required to make in connection with a property under the terms of an agreement classified as an operating lease, excluding contingent rentals and a guarantee by the lessee of the lessor's debt and the lessee's obligation to pay (apart from the rental payments) executory costs such as insurance, maintenance, and taxes. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
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- Definition
Rental expense for the reporting period incurred under operating leases, including minimum and any contingent rent expense, net of related sublease income. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
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- Definition
The total amount of sublease rental income recognized during the period that reduces the entity's rent expense incurred under operating leases. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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