Equipment - Summary of Equipment Costs (Detail) (USD $)	Dec. 31, 2013	Dec. 31, 2012
Property, Plant and Equipment [Line Items]
Property, plant, and equipment	$ 1,944,656	$ 2,762,462
Less accumulated depreciation	(1,486,744)	(1,775,909)
Equipment, net	457,912	986,553
Lab Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant, and equipment	1,083,463	1,903,533
Computer Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant, and equipment	332,386	335,264
Furniture and Fixtures [Member]
Property, Plant and Equipment [Line Items]
Property, plant, and equipment	$ 528,807	$ 523,665