Property, Plant and Equipment
 12 Months Ended
Dec. 31, 2013
Property, Plant and Equipment [Abstract]  
Property, Plant and Equipment
Property, Plant and Equipment
 
Property, plant and equipment consisted of the following at December 31, 2013 and 2012: 
 
2013
 
2012
Laboratory equipment
$
2,473,428

 
$
2,305,410

Leasehold improvements
3,166,622

 
2,817,123

Computer equipment
655,364

 
458,421

Furniture and fixtures
488,168

 
345,287

 
6,783,582

 
5,926,241

Less - accumulated depreciation
(5,401,509
)
 
(4,938,372
)
Property, plant and equipment, net
$
1,382,073

 
$
987,869



Depreciation and amortization expense on property, plant, and equipment was $463,137, $419,358, and $568,288 for the years ended December 31,2013, 2012, and 2011, respectively. For the year ended December 31, 2011, in addition to depreciation and amortization expense, the Company incurred non-cash charges of $25,000 in connection with disposals of fixed assets.