Prepaid Expenses - Prepaid Expenses (Detail) (USD $)	Jun. 30, 2014	Dec. 31, 2013
Deferred Costs Capitalized Prepaid And Other Assets Disclosure [Abstract]
Prepaid research fees	$ 634,081	$ 1,334,149
Prepaid insurance	123,296	219,651
Prepaid subscription fees	42,711	24,643
Prepaid rent	9,750	7,848
Other	32,256	23,151
Total prepaid expenses	$ 842,094	$ 1,609,442