CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $)	12 Months Ended			141 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2013
Operating activities:
Net loss	$ (16,416,233)	$ (31,735,909)	$ (50,452,165)	$ (231,477,643)
Adjustments to reconcile net loss to net cash used in operating activities:
Non-cash stock-based compensation	1,847,076	1,828,204	2,648,741	12,665,936
Depreciation and amortization	109,960	127,350	116,465	659,290
Stock issued for license fee	0	0	0	575,023
Non-cash interest expense	0	0	0	34,020
Loss (gain) on disposition of fixed assets	0	25,158	0	22,951
Fair value of warrants for finder's fee	0	0	0	433,750
Changes in operating assets and liabilities:
Prepaid contract research and manufacturing expenses, other prepaid expenses and other assets	(783,509)	615,740	(404,377)	(1,134,883)
Accounts payable, accrued contract research and manufacturing expenses and other accrued expenses	792,839	(9,848,177)	(200,603)	2,763,118
Accrued restructuring	(570,765)	841,184	0	270,419
Accrued compensation and related expenses	13,378	(1,219,502)	252,355	213,313
Net cash used in operating activities	(15,007,254)	(39,365,952)	(48,039,584)	(214,974,706)
Investing activities:
Acquisitions of property and equipment	(2,994)	(25,260)	(227,468)	(742,725)
Proceeds from sale of assets	0	12,230	0	15,907
Purchases of short-term investments	0	0	(65,605,570)	(115,143,906)
Redemptions of short-term investments	0	4,500,000	61,105,570	115,143,906
Security deposits	0	38,267	(172)	0
Net cash (used in) provided by investing activities	(2,994)	4,525,237	(4,727,640)	(726,818)
Financing activities:
Proceeds from borrowings from affiliate	0	0	0	1,745,000
(Repayment of) borrowings from line of credit	0	0	0	0
Proceeds from exercise of stock options	141,012	7,194	0	228,935
Proceeds from exercise of common stock warrants	0	0	8,480,135	9,054,546
Proceeds from sales of equity securities, net of issuance costs	31,767,667	22,151,851	37,726,538	250,317,683
Receipt of recovery of short-swing profits	0	0	73,797	73,797
Recapitalization of the Company	0	0	0	(400,000)
Receipt of cash for stock subscription receivable	0	0	0	4,625
Net cash provided by financing activities	31,908,679	22,159,045	46,280,470	261,024,586
Net increase (decrease) in cash and cash equivalents	16,898,431	(12,681,670)	(6,486,754)	45,323,062
Cash and cash equivalents, beginning of period	28,424,631	41,106,301	47,593,055	0
Cash and cash equivalents, end of period	45,323,062	28,424,631	41,106,301	45,323,062
Supplemental disclosure of cash flow information:
Cash paid for interest	$ 0	$ 0	$ 0	$ 224,328