Note 10 - Net Loss Per Share - Schedule of Antidilutive Securities (Details) - shares	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Number of potential common shares excluded (in shares)	4,908,613	4,317,405
Share-based Payment Arrangement, Option [Member]
Number of potential common shares excluded (in shares)	3,013,370	487,941
Series B Convertible Preferred Stock [Member]
Number of potential common shares excluded (in shares)	258,230	774,983
Warrant [Member]
Number of potential common shares excluded (in shares)	1,637,013	3,054,481