CONDENSED STATEMENTS OF CASH FLOWS (Unaudited) (USD $)	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013
Cash flows from operating activities:
Net loss	$ (16,680,203)	$ (20,267,256)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	95,834	89,256
Loss on retirement of fixed assets	975	2,595
Stock compensation and warrant expense	3,402,706	1,336,667
Fair value adjustment on warrant liability	(19,560,350)	3,172,324
Net foreign exchange gain	(29,131)	(140,780)
Changes in assets and liabilities:
Receivables	(3,377,135)	107,351
Interest receivable	(67,079)	(51,443)
Prepaid expenses and other current assets	251,075	335,948
Accounts payable	1,409,926	(199,435)
Accrued expenses and other current liabilities	5,788,188	407,221
Net cash used in operating activities	(28,765,194)	(15,207,552)
Cash flows from investing activities:
Purchase of short-term investments	(57,121,593)	0
Proceeds from the sale of short-term investments	33,584,980	7,000,000
Purchases of equipment and furnishings	(590,077)	(22,274)
Net cash provided by (used in) investing activities	(24,126,690)	6,977,726
Cash flows from financing activities:
Net proceeds from public offering	80,535,401	0
Proceeds from issuance of restricted stock to employee	100	0
Repurchase of common stock for treasury	(146,374)	(78,975)
Net proceeds from exercise of warrants and stock options	431,941	933
Net cash provided by (used in) financing activities	80,821,068	(78,042)
Net increase (decrease) in cash and cash equivalents	27,929,184	(8,307,868)
Cash and cash equivalents at beginning of period	11,483,112	14,344,088
Cash and cash equivalents at end of period	39,412,296	6,036,220
Supplemental disclosure of cash flow information:
Equipment and furnishings purchased on credit	155,771	4,535
Cashless warrant exercises	133	0
Repurchase of stock for treasury	11,743	15,229
Cash paid for income taxes	$ 77,071	$ 34,221