Note 8 - Common Stock Warrants (Details) - USD ($)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Aug. 16, 2022	May 10, 2022	Mar. 31, 2022	Aug. 19, 2021
Class of warrant or right, exercise price of warrants or rights (in dollars per share)	$ 2.38					$ 172.50
Warrants outstanding	1,055,672	143,602
Warrants and Rights Outstanding	$ 1,055,672	$ 143,602
Common stock warrants	805,202
Reduction in income available to common shareholders	$ (14,548,000)	$ (26,616,000)
Proceeds from exercise of warrants	$ 1,200,000
July 2021 Warrant [Member] | Altium Growth Fund, LP [Member]
Class of warrant or right, exercise price of warrants or rights (in dollars per share)	$ 181.50
Class of warrant or right, number of securities called by warrants or rights (in shares)	22,000
May 2021 Warrants [Member]
Warrants outstanding	0
May 2021 Warrants [Member] | Altium Growth Fund, LP [Member]
Warrants outstanding	0
Class of warrant or right, number of securities called by warrants or rights (in shares)		26,186			79,886
January 2022 Warrants [Member] | Altium Growth Fund, LP [Member]
Class of warrant or right, exercise price of warrants or rights (in dollars per share)	$ 55.00
Class of warrant or right, number of securities called by warrants or rights (in shares)	45,000
Senior Secured Promissory Note Warrants [Member]
Class of warrant or right, exercise price of warrants or rights (in dollars per share)	$ 194.00
Class of warrant or right, number of securities called by warrants or rights (in shares)	17,177
Senior Secured Promissory Note Warrants [Member] | Altium Growth Fund, LP [Member]
Warrants and Rights Outstanding, Term (Year)	5 years
August 2022 Public Offering Warrants [Member]
Reduction in income available to common shareholders	$ 288,000
August 2022 Public Offering Warrants [Member] | Series One Warrants [Member]
Class of warrant or right, exercise price of warrants or rights (in dollars per share)	$ 2.38
Warrants and Rights Outstanding, Term (Year)			1 year
Common stock warrants	777,399
Class of warrant or right, number of securities called by warrants or rights (in shares)	326,601		1,104,000
August 2022 Public Offering Warrants [Member] | Series Two Warrants [Member]
Class of warrant or right, exercise price of warrants or rights (in dollars per share)	$ 2.38
Warrants and Rights Outstanding, Term (Year)			5 years
Common stock warrants	625,399
Class of warrant or right, number of securities called by warrants or rights (in shares)	478,601		1,104,000
August 2022 Public Offering Warrants [Member] | Series One and Two Warrants [Member]
Class of warrant or right, exercise price of warrants or rights (in dollars per share)	$ 2.38		$ 12.50
Warrants and Rights Outstanding	$ 1,400,000
Adjusted exercise price of warrants	$ 2.81
Proceeds from exercise of warrants	$ 3,700,000
August 2022 Public Offering Warrants [Member] | Underwriter Warrant [Member]
Class of warrant or right, exercise price of warrants or rights (in dollars per share)	$ 15.63
Warrants and Rights Outstanding, Term (Year)			5 years
Class of warrant or right, number of securities called by warrants or rights (in shares)	66,240
May 2022 Registered Direct Offering Warrants [Member] | Purchase Warrants [Member]
Class of warrant or right, exercise price of warrants or rights (in dollars per share)				$ 35.53
Class of warrant or right, number of securities called by warrants or rights (in shares)				72,935
May 2022 Registered Direct Offering Warrants [Member] | Placement Agent Warrants [Member]
Class of warrant or right, exercise price of warrants or rights (in dollars per share)				$ 35.53
Class of warrant or right, number of securities called by warrants or rights (in shares)				4,376