Note 15 - Stock-based Compensation - Stock Option Activity (Details) - $ / shares	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Balance (in shares)	2,585,500	7,204,672
Balance, weighted average exercise price (in dollars per share)	$ 0.19	$ 1.32
Weighted-average remaining contractual term (Year)	3 years 6 months	9 years 2 months 12 days	5 years 3 months 18 days
Granted (in shares)	99,460,000	2,450,000
Granted, weighted average exercise price (in dollars per share)	$ 0.06	$ 0.14
Expired/Cancelled (in shares)	(97,226,624)	(7,069,172)
Expired/Cancelled, weighted average exercise price (in dollars per share)	$ 0.06	$ 1.33
Exercised (in shares)	0	0
Exercised, weighted average exercise price (in dollars per share)
Balance (in shares)	4,818,876	2,585,500	7,204,672
Balance, weighted average exercise price (in dollars per share)	$ 0.08	$ 0.19	$ 1.32