Note 10 - Stock-based Compensation - Stock Option Activity (Details) - $ / shares	3 Months Ended	9 Months Ended		12 Months Ended
	Sep. 30, 2021	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Balance (in shares)		2,585,500
Balance, weighted average exercise price (in dollars per share)		$ 0.19
Weighted-average remaining contractual term (Year)		6 years 8 months 12 days		9 years 2 months 12 days
Granted (in shares)	33,540,000	99,260,000
Granted, weighted average exercise price (in dollars per share)		$ 0.06	$ 0.09
Expired/Cancelled (in shares)		(18,700,625)
Expired/Cancelled, weighted average exercise price (in dollars per share)		$ 0.07
Exercised (in shares)		0
Exercised, weighted average exercise price (in dollars per share)		$ 0
Balance (in shares)	83,144,875	83,144,875		2,585,500
Balance, weighted average exercise price (in dollars per share)	$ 0.06	$ 0.06		$ 0.19