Consolidated Balance Sheets (USD $)	Jun. 30, 2014	Dec. 31, 2013
Current assets:
Cash and cash equivalents	$ 16,214,690	$ 23,644,542
Other current assets	1,481,526	1,122,576
Total current assets	17,696,216	24,767,118
Property & equipment, net of accumulated depreciation of $1,905,854 and $1,718,477, respectively	1,234,826	1,295,024
Other long-term assets	162,045	177,666
Total assets	19,093,087	26,239,808
Current liabilities:
Accounts payable	835,570	696,155
Accrued expenses	1,627,271	1,232,990
Deferred revenue	1,230,746	1,395,348
Total current liabilities	3,693,587	3,324,493
Long term liabilities:
Deferred revenue, net of current portion	1,846,120	2,338,041
Total liabilities	5,539,707	5,662,534
Commitments and contingencies	0	0
Stockholders' equity:
Preferred stock, no par value, 10,000,000 shares authorized, none issued and outstanding	0	0
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	147,363,541	146,569,758
Deficit accumulated during the development stage	(134,086,778)	(126,267,945)
Total stockholders' equity	13,553,380	20,577,274
Total liabilities and stockholders' equity	$ 19,093,087	$ 26,239,808