Consolidated Balance Sheets - USD ($)	Dec. 31, 2015	Dec. 31, 2014
Current assets:
Cash and cash equivalents	$ 9,265,144	$ 12,686,881
Investment securities – available for sale, at fair value	10,799,890	24,173,406
Accrued interest receivable on investment securities	26,729	210,030
Advances and deposits on clinical programs	89,186	200,821
Other current assets	100,367	235,133
	20,281,316	37,506,271
Property and equipment (at cost, less accumulated depreciation and amortization of $2,058,483 and $1,633,517, respectively)	854,872	1,170,497
Other assets:
Goodwill	1,976,101	1,976,101
Security deposit on letter of credit	100,000	150,000
Deferred financing fees	26,131	68,049
Other assets	14,386	21,886
	27,918,346	28,017,764
Total assets	49,054,534	66,694,532
Current liabilities:
Accounts payable ─ trade	2,830,227	3,480,225
Other accrued liabilities	1,919,769	2,456,365
Notes payable - current portion	4,099,847	3,654,231
Deferred revenue – current portion	500,000	500,000
Total current liabilities	9,349,843	10,090,821
Earn-Out milestone liability	13,921,412	13,663,710
Common stock warrant liability	0	275,008
Note payable – non-current portion	2,350,018	6,053,065
Deferred revenue – non-current portion	3,000,000	3,500,000
Other liabilities – non-current	47,597	286,592
Total liabilities	28,668,870	33,869,196
Commitments and contingencies	0	0
Stockholders’ equity:
Preferred Stock - $0.01 par value (100,000 shares authorized and no shares issued or outstanding at December 31, 2015 and 2014, respectively)	0	0
Common stock - $0.01 par value (75,000,000 shares authorized; 23,395,211 and 20,097,603 shares issued at December 31, 2015 and 2014 and 23,319,287 and 19,984,203 shares outstanding at December 31, 2015 and 2014, respectively)	233,952	200,976
Additional paid-in capital	239,668,235	229,778,703
Accumulated other comprehensive loss	(3,858)	(16,032)
Accumulated deficit	(218,130,360)	(195,073,702)
	21,767,969	34,889,945
Treasury stock, at cost (75,924 and 113,400 shares at December 31, 2015 and 2014, respectively)	(1,382,305)	(2,064,609)
Total stockholders’ equity	20,385,664	32,825,336
Total liabilities and stockholders’ equity	49,054,534	66,694,532
In Process Research and Development [Member]
Other assets:
In-process research and development	$ 25,801,728	$ 25,801,728