Condensed Consolidated Balance Sheets (Current Period Unaudited) - USD ($)	Jun. 30, 2016	Dec. 31, 2015
In Process Research and Development [Member]
Other assets:
In-process research and development	$ 25,801,728	$ 25,801,728
Cash and cash equivalents	12,307,789	9,265,144
Investment securities – available for sale, at fair value	2,160,000	10,799,890
Accrued interest receivable on investment securities	21	26,729
Advances, deposits and other current assets	500,775	189,553
Subtotal current assets	14,968,585	20,281,316
Property and equipment (at cost, less accumulated depreciation and amortization of $2,298,483 and $2,058,483, respectively)	657,630	854,872
Goodwill	1,976,101	1,976,101
Security deposit on letter of credit	100,000	100,000
Patent licensing fees and other assets, net	10,636	14,386
Subtotal other assets	27,888,465	27,892,215
Total assets	43,514,680	49,028,403
Current liabilities:
Accounts payable - trade	2,949,152	2,830,227
Other accrued liabilities	2,378,544	1,919,769
Notes payable - current portion	4,578,650	4,073,716
Deferred revenue – current portion	500,000	500,000
Total current liabilities	10,406,346	9,323,712
Notes payable – non-current portion		2,350,018
Earn-out milestone liability	13,815,384	13,921,412
Deferred revenue – non-current portion	2,750,000	3,000,000
Other liabilities – non-current	30,881	47,597
Total liabilities	27,002,611	28,642,739
Commitments and contingencies
Stockholders’ equity:
Preferred Stock - $0.01 par value (100,000 shares authorized and no shares issued or outstanding at June 30, 2016 and December 31, 2015, respectively)	0	0
Common stock - $0.01 par value (112,500,000 shares authorized; 25,833,493 and 23,395,211 shares issued at June 30, 2016 and December 31, 2015, respectively and 25,780,554 and 23,319,287 shares outstanding at June 30, 2016 and December 31, 2015, respectively)	258,335	233,952
Additional paid-in capital	245,972,736	239,668,235
Accumulated other comprehensive loss		(3,858)
Accumulated deficit	(228,755,172)	(218,130,360)
Subtotal	17,475,899	21,767,969
Treasury stock, at cost (52,939 and 75,924 shares at June 30, 2016 and December 31, 2015, respectively)	(963,830)	(1,382,305)
Total stockholders’ equity	16,512,069	20,385,664
Total liabilities and stockholders’ equity	$ 43,514,680	$ 49,028,403