Note 10 - Share Based Payments - Stock Options Exercisable and Expected to Vest (Details)	12 Months Ended
	Dec. 31, 2020 USD ($) $ / shares shares
Stock options exercisable, Options (in shares)	1,816,666
Stock options exercisable, Weighted average remaining contractual life (Year)	5 years 302 days
Stock options exercisable, Weighted average exercise price (in dollars per share) | $ / shares	$ 0.19
Stock options exercisable, Aggregate intrinsic value | $	$ 937
Stock options expected to vest, Options (in shares)	83,334
Stock options expected to vest, Weighted average remaining contractual life (Year)	7 years 21 days
Stock options expected to vest, Weighted average exercise price (in dollars per share) | $ / shares	$ 0.49
Stock options expected to vest, Aggregate intrinsic value | $	$ 18
Options exercisable and expected to vest, Options (in shares)	1,900,000