Balance Sheets (Current Period Unaudited) (USD $)	Jun. 30, 2013	Dec. 31, 2012
ASSETS
Cash and cash equivalents	$ 6,020,528	$ 14,991,488
Investment securities – available for sale, at fair value	42,706,769	8,037,620
Accrued interest receivable on investment securities	206,209	65,925
Advances and deposits for investigator grants	118,240	246,252
Other current assets	520,725	307,699
Total current assets	49,572,471	23,648,984
Property and equipment (at cost, less accumulated depreciation of $1,074,961 and $924,961, respectively)	1,022,115	1,114,621
Deposits, deferred fees and other assets	395,733	567,188
Patent licensing fees, net	24,375	28,125
Total other assets	420,108	595,313
Total assets	51,014,694	25,358,918
LIABILITIES AND STOCKHOLDERS' EQUITY
Accounts payable	1,522,710	2,339,768
Accrued liabilities	1,782,967	1,254,979
Notes payable - current portion	1,904,770	1,410,455
Deferred revenue - current portion	500,000
Total current liabilities	5,710,447	5,005,202
Common stock warrant liability	4,733,817	4,283,932
Notes payable – non-current portion	2,847,644	3,661,147
Deferred revenue - non-current portion	4,250,000
Other non-current liabilities	483,108	446,779
Total liabilities	18,025,016	13,397,060
Stockholders' equity:
Common stock, $0.01 par value; 75,000,000 shares authorized; 61,823,340 and 37,967,708 shares issued at June 30, 2013 and December 31, 2012 and 61,160,961 and 37,302,785 shares outstanding at June 30, 2013 and December 31, 2012, respectively	618,233	379,677
Additional paid-in capital	190,963,230	165,276,069
Accumulated other comprehensive loss	(213,841)	(126,607)
Accumulated deficit	(155,697,737)	(150,876,770)
Subtotal	35,669,885	14,652,369
Treasury stock, at cost (662,379 and 664,921 shares at June 30, 2013 and December 31, 2012, respectively)	(2,680,207)	(2,690,511)
Total stockholders' equity	32,989,678	11,961,858
Total liabilities and stockholders' equity	$ 51,014,694	$ 25,358,918