Note 16 - Warrants - Warrant Activity (Details) - $ / shares	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Outstanding, number of warrant shares (in shares)	46,498,909
Outstanding, weighted average exercise price (in dollars per share)	$ 0.71
Outstanding, weighted average remaining contractual life (Year)		2 years 4 months 24 days
Outstanding, weighted average fair value (in dollars per share)		$ 0.20
Exercised, number of warrant shares (in shares)	(45,317,101)
Exercised, weighted average exercise price (in dollars per share)	$ 0.68
Reserve for future issuance, number of warrant shares (in shares)		644,966	1,753,523
Reserve for future issuance, weighted average exercise pric (in dollars per share)		$ 0.35	$ 1.39
Reserve for future issuance, weighted average remaining contractual life (Year)		1 year 3 months 18 days	2 years 2 months 12 days
Reserve for future issuance, weighted average fair value (in dollars per share)		$ 0.45	$ 1.22
Exchanged, number of warrant shares (in shares)	(61,508)
Expired, weighted average exercise price (in dollars per share)	$ 1.35
Outstanding, number of warrant shares (in shares)		46,498,909
Outstanding, weighted average exercise price (in dollars per share)		$ 0.71
Stock Warrants [Member]
Outstanding, number of warrant shares (in shares)		2,071,172	333,034
Outstanding, weighted average exercise price (in dollars per share)		$ 2.05	$ 13.39
Outstanding, weighted average remaining contractual life (Year)	3 years		2 years 4 months 24 days	3 years 8 months 12 days
Outstanding, weighted average fair value (in dollars per share)	$ 0.55		$ 1.34	$ 3.38
Exercised, number of warrant shares (in shares)		(4,911,764)	(15,385)
Exercised, weighted average exercise price (in dollars per share)		$ 0.68	$ 13.00
Granted, number of warrant shares (in shares)		50,735,292
Granted, weighted average exercise price (in dollars per share)		$ 0.68
Granted, weighted average remaining contractual life (Year)		2 years 4 months 24 days
Restricted stock units, Granted, weighted average grant date fair value (in dollars per share)		$ 0.19
Exchanged, number of warrant shares (in shares)		(2,040,757)
Exchanged, weighted average exercise price (in dollars per share)		$ 1.24
Outstanding, number of warrant shares (in shares)	1,120,300		2,071,172	333,034
Outstanding, weighted average exercise price (in dollars per share)	$ 1.94		$ 2.05	$ 13.39