Other Current Assets (Detail) (USD $)	Jun. 30, 2013	Dec. 31, 2012
Other Assets, Current [Line Items]
Supplies inventory	$ 946,713	$ 604,179
Deferred offering costs	440,305	341,166
Prepaid expenses	306,992	132,201
Other current assets	$ 1,694,010	$ 1,077,546