Condensed Consolidated Balance Sheets (USD $)	Mar. 31, 2012	Dec. 31, 2011
Assets
Cash and cash equivalents	$ 51,680,461	$ 41,106,301
Short-term investments		4,500,000
Prepaid contract research and manufacturing	437,252	173,592
Other prepaid expenses and other current assets	1,090,038	793,521
Total current assets	53,207,751	46,573,414
Property and equipment, net	277,987	291,024
Other assets	38,267	38,267
Total Assets	53,524,005	46,902,705
Liabilities and Stockholders' Equity
Accounts payable	3,732,425	4,866,356
Accrued compensation and related expenses	793,843	1,419,437
Accrued contract research and manufacturing	6,159,053	5,245,339
Other accrued expenses	1,759,788	1,706,763
Total liabilities	12,445,109	13,237,895
Commitments
Stockholders' equity:
Preferred stock, $0.0001 par value, 5,000,000 shares authorized, no shares issued and outstanding
Common stock, $0.0001 par value, 100,000,000 shares authorized, 67,040,569 and 62,034,146 shares issued and outstanding, respectively	6,704	6,203
Additional paid-in capital	239,956,911	216,984,108
Deficit accumulated during the development stage	(198,884,719)	(183,325,501)
Total stockholders' equity	41,078,896	33,664,810
Total liabilities and stockholders' equity	$ 53,524,005	$ 46,902,705