Note 17 - Net Loss Per Share Attributable to Common Stockholders - Summary of Antidilutive Securities (Details) - shares	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Potentially dilutive securities excluded from denominator of the diluted earnings per share computation (in shares)	19,163,520	1,261,124
Share-based Payment Arrangement, Option [Member]
Potentially dilutive securities excluded from denominator of the diluted earnings per share computation (in shares)	1,583,575	839,396
Warrant [Member] | Common Stock [Member]
Potentially dilutive securities excluded from denominator of the diluted earnings per share computation (in shares)	17,579,945	9,658
Warrant [Member] | Convertible Preferred Stock [Member]
Potentially dilutive securities excluded from denominator of the diluted earnings per share computation (in shares)		891
Series B and C Convertible Preferred Stock, Including Cumulative Dividends [Member]
Potentially dilutive securities excluded from denominator of the diluted earnings per share computation (in shares)		213,760
Series A Convertible Preferred Stock [Member]
Potentially dilutive securities excluded from denominator of the diluted earnings per share computation (in shares)		12,260
Convertible Debt Securities [Member]
Potentially dilutive securities excluded from denominator of the diluted earnings per share computation (in shares)		185,159