Condensed Statements of Cash Flows (Unaudited) (USD $)	9 Months Ended
	Sep. 30, 2011		Sep. 30, 2010
Cash flows from operating activities:
Net loss	$ (15,862,380)		$ (14,597,699)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	415,592		396,878
Noncash compensation	2,911,260		562,799
Gain on disposal of fixed assets			(27)
Changes in operating assets and liabilities:
(Increase) decrease in prepaid expenses and other current assets	(336,036)		271,806
Decrease in accounts payable and accrued expenses	(366,642)		(1,799)
Increase in other assets	(248,793)		(289,705)
Increase in deferred rent	25,434		78,228
Decrease in other current liabilities	(1,288)		(3,559)
Net cash used in operating activities	(13,462,853)		(13,583,078)
Cash flows from investing activities:
Purchases of property and equipment	(58,680)		(1,052,835)
Proceeds from sale of fixed assets			1,500
Net cash used in investing activities	(58,680)		(1,051,335)
Cash flows from financing activities:
Proceeds from exercise of stock options			26,070
Proceeds from exercise of stock warrants			1,691,633
Proceeds from public offering			16,500,000
Expenses related to public offering			(1,244,329)
Proceeds from Committed Equity Financing Facility			3,750,000
Expenses related to Committed Equity Financing Facility			(6,717)
Net cash provided by financing activities			20,716,657
Net (decrease) increase in cash and cash equivalents	(13,521,533)		6,082,244
Cash and cash equivalents at beginning of period	30,520,812	[1]	29,673,420
Cash and cash equivalents at end of period	16,999,279		35,755,664
Supplemental Schedule of Non-cash Investing and Financing Activities
Deferred financing costs charged to additional paid-in capital			$ 23,179

[1] Derived from the audited balance sheet as of December 31, 2010