|
Property and equipment (Details) (USD $)
|
3 Months Ended | 9 Months Ended | |||
|---|---|---|---|---|---|
|
Sep. 30, 2013
|
Sep. 30, 2012
|
Sep. 30, 2013
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Sep. 30, 2012
|
Dec. 31, 2012
|
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| Property, Plant and Equipment [Line Items] | |||||
| Property and equipment | $ 5,583,139 | $ 5,583,139 | $ 5,562,898 | ||
| Less accumulated depreciation | 3,264,072 | 3,264,072 | 3,078,359 | ||
| Total property and equipment, net | 2,319,067 | 2,319,067 | 2,484,539 | ||
| Depreciation expense | 59,000 | 91,000 | 190,000 | 277,000 | |
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Land and improvements [Member]
|
|||||
| Property, Plant and Equipment [Line Items] | |||||
| Property and equipment | 1,107,508 | 1,107,508 | 1,107,508 | ||
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Building [Member]
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| Property, Plant and Equipment [Line Items] | |||||
| Property and equipment | 2,589,231 | 2,589,231 | 2,589,231 | ||
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Building improvements [Member]
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|||||
| Property, Plant and Equipment [Line Items] | |||||
| Property and equipment | 253,526 | 253,526 | 251,049 | ||
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Laboratory equipment [Member]
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| Property, Plant and Equipment [Line Items] | |||||
| Property and equipment | 1,220,735 | 1,220,735 | 1,211,418 | ||
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Office and computer equipment [Member]
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| Property, Plant and Equipment [Line Items] | |||||
| Property and equipment | $ 412,139 | $ 412,139 | $ 403,692 | ||