Consolidated Statements of Cash Flows (USD $)	12 Months Ended			97 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2013
Cash flows from operating activities:
Net income (loss)	$ (38,755,922)	$ 4,663,681	$ (34,728,215)	$ (81,909,055)
Adjustments to reconcile net income (loss) to net cash used in operating activities:
Depreciation and amortization expense	740,692	366,893	144,662	1,345,212
Non-cash derivative (gain) losses	18,871,329	(17,479,674)	26,065,579	31,409,816
Non-cash interest expense		21,870		984,704
Non-cash loss from modification of warrants	764,769			764,769
Common stock issued to 401(k) plan	191,802	91,524	41,662	324,988
Common stock issued for services		24,750	209,451	234,201
Share-based compensation expense	3,135,646	1,232,959	921,512	6,168,957
Changes in operating assets and liabilities:
Restricted cash	(120)	(53,468)	(547,883)	(601,471)
Prepaid expenses and other current assets	123,780	(60,575)	(12,805)	(30,766)
Other assets	4,560		(125,000)	(195,440)
Accounts payable	(253,290)	585,355	230,250	899,260
Accrued interest payable				(15,256)
Accrued expenses	270,910	402,906	370,822	1,292,185
Net cash used in operating activities	(14,905,844)	(10,203,779)	(7,429,965)	(39,327,896)
Cash flows from investing activities:
Purchases of property and equipment	(748,460)	(2,140,853)	(278,923)	(3,520,021)
Net cash used in investing activities	(748,460)	(2,140,853)	(278,923)	(3,520,021)
Cash flows from financing activities:
Proceeds from issuance of note payable	149,768			149,768
Repayment of note payable	(57,284)			(57,284)
Proceeds from issuance of convertible notes payable				4,181,000
Proceeds from convertible bridge notes				500,000
Principal payments on capital lease obligation	(32,606)	(33,361)	(24,774)	(90,741)
Proceeds from loans payable	342,000	1,747,000	151,733	2,240,733
Repayment of loans payable		(303,372)	(17,361)	(320,733)
Proceeds from issuance of common stock and warrants	16,407,657	19,395,743	2,998,808	50,225,495
Net cash provided by financing activities	16,809,535	20,806,010	3,108,406	56,828,238
Increase (Decrease) in cash and cash equivalents	1,155,231	8,461,378	(4,600,482)	13,980,321
Cash and cash equivalents at beginning of period	12,825,090	4,363,712	8,964,194
Cash and cash equivalents at end of period	13,980,321	12,825,090	4,363,712	13,980,321
Supplemental disclosure of cash flow information and non-cash transactions:
Cash paid for interest	125,342	49,862	8,530	281,251
Conversion of convertible notes payable and accrued interest into common stock				4,672,484
Conversion of convertible bridge note payable and accrued interest into common stock				504,597
Asset acquired through capital lease obligation			93,540	93,540
Beneficial conversion feature on convertible and bridge notes payable				134,410
Fair value of warrants issued with bridge notes payable				178,726
Fair value of warrants issued in connection with loan agreement		31,916	10,051	41,967
Issuance of founders shares				248
Reclassification of derivative warrant liability to additional paid-in capital	$ 33,456,147	$ 3,408,738	$ 1,239,539	$ 38,104,424