Condensed Consolidated Balance Sheets (Current Period Unaudited) - USD ($)	Mar. 31, 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	$ 14,310,542	9,265,144
Investment securities – available for sale, at fair value		10,799,890
Accrued interest receivable on investment securities		26,729
Advances and deposits and other current assets	$ 371,655	189,553
	14,682,197	20,281,316
Property and equipment (at cost, less accumulated depreciation and amortization of $2,178,483 and $2,058,483, respectively)	756,750	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	12,511	14,386
	27,890,340	27,892,215
Total assets	43,329,287	49,028,403
Current liabilities:
Accounts payable - trade	2,764,941	2,830,227
Other accrued liabilities	2,097,041	1,919,769
Notes payable - current portion	4,201,019	4,073,716
Deferred revenue – current portion	500,000	500,000
Total current liabilities	9,563,001	9,323,712
Notes payable – non-current portion	1,319,414	2,350,018
Earn-out milestone liability	14,224,068	13,921,412
Deferred revenue – non-current portion	2,875,000	3,000,000
Other liabilities – non-current	38,784	47,597
Total liabilities	$ 28,020,267	$ 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 March 31, 2016 and December 31, 2015, respectively)
Common stock - $0.01 par value (75,000,000 shares authorized; 23,489,711 and 23,395,211 shares issued at March 31, 2016 and December 31, 2015, respectively and 23,424,699 and 23,319,287 shares outstanding at March 31, 2016 and December 31, 2015, respectively)	$ 234,897	$ 233,952
Additional paid-in capital	$ 240,282,304	239,668,235
Accumulated other comprehensive loss		(3,858)
Accumulated deficit	$ (224,024,545)	(218,130,360)
	16,492,656	21,767,969
Treasury stock, at cost (65,012 and 75,924 shares at March 31, 2016 and December 31, 2015, respectively)	(1,183,636)	(1,382,305)
Total stockholders’ equity	15,309,020	20,385,664
Total liabilities and stockholders’ equity	$ 43,329,287	$ 49,028,403