Consolidated Balance Sheets (Unaudited) (USD $)	Sep. 30, 2011	Dec. 31, 2010
Current assets:
Cash and cash equivalents	$ 15,985,299	$ 8,554,151
Short-term investments	36,702,869	11,014,747
Prepaid expenses and other current assets	1,380,336	599,042
Accounts receivable	105,402	178,654
Total current assets	54,173,906	20,346,594
Property and equipment, net	687,734	1,090,029
Long-term investments	999,870	0
Other assets	78,740	52,514
Total assets	55,940,250	21,489,137
Current liabilities:
Accounts payable	2,649,345	2,768,020
Accrued expenses	2,537,305	2,917,347
Current portion of notes payable	243,056	243,056
Capital lease obligations	22,113	180,792
Deferred revenue	41,667	129,167
Other current liabilities	258,382	238,703
Total current liabilities	5,751,868	6,477,085
Long-term liabilities:
Notes payable, net of current portion	121,527	303,819
Other liabilities, net of current portion	688,830	867,455
Total long-term liabilities	810,357	1,171,274
Total liabilities	6,562,225	7,648,359
Stockholders' equity:
Preferred stock, $.001 par value; 5,000,000 shares authorized at September 30, 2011 and December 31, 2010, none issued and outstanding
Common stock, $.001 par value; 150,000,000 shares authorized at September 30, 2011 and December 31, 2010, respectively; 78,286,957 and 62,423,358 shares issued and outstanding at September 30, 2011 and December 31, 2010 respectively	78,287	62,423
Additional paid-in capital	326,584,914	270,187,742
Accumulated other comprehensive (loss) income	(33,006)	542
Warrants	8,309,413	11,145,558
Accumulated deficit	(285,561,583)	(267,555,487)
Total stockholders' equity	49,378,025	13,840,778
Total liabilities and stockholders' equity	$ 55,940,250	$ 21,489,137