Condensed Statements of Cash Flows (Unaudited) (USD $)	6 Months Ended
	Jun. 30, 2011		Jun. 30, 2010
Cash flows from operating activities:
Net loss	$ (9,751,726)		$ (9,642,596)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	283,785		253,492
Noncash compensation	734,222		366,382
Changes in operating assets and liabilities:
(Increase) decrease in prepaid expenses and other current assets	(410,357)		322,685
Decrease in accounts payable and accrued expenses	(419,525)		(124,669)
Increase in other assets			(273,220)
Increase in deferred rent	16,956		52,152
Decrease in other current liabilities	(647)		(8,484)
Net cash used in operating activities	(9,547,292)		(9,054,258)
Cash flows from investing activities:
Purchases of property and equipment	(30,811)		(637,014)
Proceeds from sale of fixed assets			1,473
Net cash used in investing activities	(30,811)		(635,541)
Cash flows from financing activities:
Proceeds from exercise of stock options			26,070
Proceeds from exercise of stock warrants			1,691,633
Expenses related to public offering			(130,086)
Proceeds from Committed Equity Financing Facility			3,750,000
Expenses related to Committed Equity Financing Facility			(6,717)
Net cash provided by financing activities			5,330,900
Net decrease in cash and cash equivalents	(9,578,103)		(4,358,899)
Cash and cash equivalents at beginning of period	30,520,812	[1]	29,673,420
Cash and cash equivalents at end of period	20,942,709		25,314,521
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