|
Property and equipment (Details) (USD $)
|
12 Months Ended | ||
|---|---|---|---|
|
Dec. 31, 2013
|
Dec. 31, 2012
|
Dec. 31, 2011
|
|
| Property and equipment Abstract] | |||
| Depreciation expense | $ 244,000 | $ 352,000 | $ 402,000 |
| Property, Plant and Equipment [Line Items] | |||
| Property and equipment | 5,497,099 | 5,562,898 | |
| Less accumulated depreciation | 3,230,117 | 3,078,359 | |
| Property and equipment, net | 2,266,982 | 2,484,539 | |
|
Land and improvements [Member]
|
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| Property, Plant and Equipment [Line Items] | |||
| Property and equipment | 1,107,508 | 1,107,508 | |
|
Building [Member]
|
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| Property, Plant and Equipment [Line Items] | |||
| Property and equipment | 2,589,231 | 2,589,231 | |
|
Building improvements [Member]
|
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| Property, Plant and Equipment [Line Items] | |||
| Property and equipment | 253,526 | 251,049 | |
|
Laboratory equipment [Member]
|
|||
| Property, Plant and Equipment [Line Items] | |||
| Property and equipment | 1,220,735 | 1,211,418 | |
|
Office and computer equipment [Member]
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| Property, Plant and Equipment [Line Items] | |||
| Property and equipment | $ 326,099 | $ 403,692 | |