Note 7 - Common Stock Warrants - Summary of Warrant Activity (Details) - $ / shares	9 Months Ended	12 Months Ended
	Sep. 30, 2022	Dec. 31, 2021
Warrants and Rights Note Disclosure [Abstract]
Warrants outstanding, balance (in shares)	7,181,741
Warrants outstanding, weighted average exercise price (in dollars per share)	$ 0.44	$ 5.96
Warrants outstanding, December 31, 2021	3 years 14 days	4 years 5 months 12 days
Class of warrant or right, issued during period (in shares)	119,827,491
Granted, weighted average exercise price (in dollars per share)	$ 0.28
Granted, weighted average remaining contractual life	3 years 14 days
Exercised (in shares)	(3,994,302)
Exercised, weighted average exercise price	$ 3.88
Exercised, weighted average remaining contractual life	4 years 1 month 9 days
Forfeited, expired or cancelled (in shares)	(90,018)
Forfeited, expired, or cancelled, weighted average exercise price	$ 81.37
Warrants outstanding, balance (in shares)	122,924,912	7,181,741