Condensed Balance Sheets (USD $)	Mar. 31, 2013	Dec. 31, 2012
Current assets:
Cash and cash equivalents	$ 14,421,176	$ 2,505,076
Prepaid expenses and other current assets	447,816	161,303
Total current assets	14,868,992	2,666,379
Deferred financing costs	2,026,569	319,890
Property and equipment, net	1,451,307	21,976
Total assets	18,346,868	3,008,245
Current liabilities:
Secured convertible notes	17,600,000
Warrant liability	4,394,500
Accounts payable	3,484,421	1,768,861
Accrued expenses and other liabilities	1,380,630	3,713,508
Total current liabilities	26,859,551	5,482,369
Commitments and contingencies (Note 8)
Stockholders' (deficit) equity
Common stock, $0.001 par value; 22,000,000 shares authorized at December 31, 2012 and March 31, 2013; 3,010,101 shares issued and outstanding at December 31, 2012 and March 31, 2013	3,010	3,010
Additional paid-in capital	6,580,135	6,365,460
Deficit accumulated during development stage	(70,873,227)	(64,619,994)
Total stockholders' (deficit) equity	(64,290,082)	(58,251,523)
Total liabilities, convertible preferred stock, and stockholders' (deficit) equity	18,346,868	3,008,245
Series A Preferred Stock
Convertible preferred stock
Cumulative convertible preferred stock	6,388,092	6,388,092
Series B Preferred Stock
Convertible preferred stock
Cumulative convertible preferred stock	$ 49,389,307	$ 49,389,307