Summary of Significant Accounting Policies - Research and Development Costs (Details) (USD $)	3 Months Ended				12 Months Ended			3 Months Ended	6 Months Ended	12 Months Ended		0 Months Ended	6 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2010 Collaborative arrangement [Member]	Dec. 31, 2010 Collaborative arrangement [Member]	Dec. 31, 2012 Collaborative arrangement [Member]	Dec. 31, 2011 Collaborative arrangement [Member]	Jul. 02, 2010 Collaborative arrangement [Member] Maximum [Member]	Jul. 02, 2010 Collaborative arrangement [Member] Maximum [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Derivative gain (loss) fair value of stock warrants	$ (1,595,530)	$ 1,065,498	$ (205,700)	$ (6,259,367)	$ (6,995,099)	$ (556,662)	$ 5,229,089
Research and Development Arrangement Contract to Perform for Others, Amount												7,000,000	7,000,000
Research and Development Arrangement, Contract to Perform for Others, Costs Incurred, Gross											3,200,000
Research and Development Expense					770,642	2,779,058	8,581,874		6,300,000	400,000	700,000
increase decrease in research and development expense								$ 244,479