Consolidated Balance Sheets (Unaudited) (USD $)	Jun. 30, 2011	Dec. 31, 2010
Current assets:
Cash and cash equivalents	$ 16,713,120	$ 8,554,151
Short-term investments	33,946,530	11,014,747
Prepaid expenses and other current assets	1,016,097	599,042
Accounts receivable	74,592	178,654
Total current assets	51,750,339	20,346,594
Property and equipment, net	828,680	1,090,029
Long-term investments	7,297,127	0
Other assets	54,053	52,514
Total assets	59,930,199	21,489,137
Current liabilities:
Accounts payable	2,305,001	2,768,020
Accrued expenses	1,987,345	2,917,347
Current portion of notes payable	243,056	243,056
Capital lease obligations	68,313	180,792
Deferred revenue	54,167	129,167
Other current liabilities	304,663	238,703
Total current liabilities	4,962,545	6,477,085
Long-term liabilities:
Notes payable, net of current portion	182,291	303,819
Other liabilities, net of current portion	743,655	867,455
Total long-term liabilities	925,946	1,171,274
Total liabilities	5,888,491	7,648,359
Stockholders' equity:
Preferred stock, $.001 par value; 5,000,000 shares authorized at June 30, 2011 and December 31, 2010, none issued and outstanding	0	0
Common stock, $.001 par value; 150,000,000 shares authorized at June 30, 2011 and December 31, 2010, respectively; 77,889,178 and 62,423,358 shares issued and outstanding at June 30, 2011 and December 31, 2010 respectively	77,889	62,423
Additional paid-in capital	325,856,561	270,187,742
Accumulated other comprehensive income	375	542
Warrants	8,392,001	11,145,558
Accumulated deficit	(280,285,118)	(267,555,487)
Total stockholders' equity	54,041,708	13,840,778
Total liabilities and stockholders' equity	$ 59,930,199	$ 21,489,137