Note 11 - Stock-based Compensation - Non-vested Restricted Stock (Details) - Restricted Stock [Member]	9 Months Ended
	Sep. 30, 2021 $ / shares shares
Non-vested (in shares) | shares	4,701,556
Non-vested, weighted average grant date fair value (in dollars per share) | $ / shares	$ 0.79
Granted (in shares) | shares	4,807,378
Granted, weighted average grant date fair value (in dollars per share) | $ / shares	$ 5.08
Vested (in shares) | shares	(2,585,547)
Vested, weighted average grant date fair value (in dollars per share) | $ / shares	$ 0.99
Canceled or forfeited (in shares) | shares	(129,149)
Canceled or forfeited, weighted average grant date fair value (in dollars per share) | $ / shares	$ 0.84
Non-vested (in shares) | shares	6,794,238
Non-vested, weighted average grant date fair value (in dollars per share) | $ / shares	$ 3.75