Consolidated Balance Sheets (USD $)	Mar. 31, 2014	Dec. 31, 2013
Current assets:
Cash and cash equivalents	$ 19,659,525	$ 23,644,542
Other current assets	1,565,648	1,122,576
Total current assets	21,225,173	24,767,118
Property & equipment, net of accumulated depreciation of $1,807,196 and $1,718,477, respectively	1,289,623	1,295,024
Other long-term assets	166,649	177,666
Total assets	22,681,445	26,239,808
Current liabilities:
Accounts payable	715,319	696,155
Accrued expenses	1,228,667	1,232,990
Deferred revenue	1,395,348	1,395,348
Total current liabilities	3,339,334	3,324,493
Long term liabilities:
Deferred revenue, net of current portion	1,989,204	2,338,041
Total liabilities	5,328,538	5,662,534
Commitments and contingencies
Stockholders' equity:
Preferred stock, no par value, 10,000,000 shares authorized, none issued and outstanding
Common stock, $0.01 par value, 100,000,000 shares authorized, 27,661,675 and 27,546,058 shares issued and outstanding	276,617	275,461
Additional paid in capital	146,999,809	146,569,758
Deficit accumulated during the development stage	(129,923,519)	(126,267,945)
Total stockholders' equity	17,352,907	20,577,274
Total liabilities and stockholders' equity	$ 22,681,445	$ 26,239,808