Note 4 - Fair Values of Financial Instruments (Tables)

12 Months Ended

Dec. 31, 2015

Fair Value Disclosures [Abstract]

Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block]

	Total Fair Value on the Balance Sheet		Quoted Prices In Active Markets For Identical Assets /Liabilities (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Assets:
Recurring items as of December 31, 2015
Short-term investments available for sale	$	10,799,890	$	10,799,890		─		─
Recurring items as of December 31, 2014
Short-term investments available for sale	$	24,173,406	$	24,173,406		─		─
Non-recurring items as of December 31, 2014
In-process research and development (Note 5)	$	25,801,728		─		─	$	25,801,728
Goodwill (Note 5)	$	1,976,101		─		─	$	1,976,101
Liabilities:
Recurring items as of December 31, 2015
Common stock warrant liability (Note 13)	─			─		─		─
Earn-out milestone liability (Note 12)	$	13,921,412		─		─	$	13,921,412
Recurring items as of December 31, 2014
Common stock warrant liability (Note 13)	$	275,008		─		─	$	275,008
Earn-out milestone liability (Note 12)	$	13,663,710					$	13,663,710