Note 2 - Summary of Significant Accounting Policies (Tables)

3 Months Ended

12 Months Ended

Mar. 31, 2016

Dec. 31, 2015

Notes Tables

Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block]

	Three Months Ended
	March 31,
	2016		2015
Stock options to purchase common stock		1,131,768		363,252
Warrants to purchase common stock		401,446		301,399
Rights to common stock		-		70,755

	Year Ended December 31,
	2015		2014
Stock options to purchase common stock		1,022,195		286,501
Warrants to purchase common stock		383,321		224,248
Rights to common stock		-		70,755