Note 8 - Net Loss Per Share (Tables)

3 Months Ended

Mar. 31, 2019

Notes Tables

Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]

	Three Months Ended March 31,
	2019			2018
Numerator
Net loss attributable to common shareholders	$	(4,073,307	)	$	(1,874,382	)
Denominator
Weighted average common shares outstanding used to compute net loss per share, basic and diluted		6,565,514			220,996
Net loss per share of common stock, basic and diluted:	$	(0.62	)	$	(8.48	)

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

	Three Months Ended March 31,
	2019		2018
Options to purchase common stock		783,383		14,473
Series B convertible preferred stock		458,994
Warrants to purchase common stock		3,369,468		76,235
		4,611,845		90,708