Note 10 - Stock-Based Compensation (Tables)

6 Months Ended

Jun. 30, 2015

Notes Tables

Schedule of Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Table Text Block]

	Three Months Ended June 30 ,				Six Months Ended June 30 ,
	2015		2014		2015		2014
Research and development	$	152,645	$	32,825	$	384,170	$	32,825
General and administrative		374,544		108,490		748,446		258,375
Total stock-based compensation expense	$	527,189	$	141,315	$	1,132,616	$	291,200