Note 7 - Stock-based Compensation - Restricted Stock Activity (Details) - Restricted Stock [Member]	9 Months Ended
	Sep. 30, 2023 $ / shares shares
Nonvested (in shares) | shares	4,223,023
Nonvested, weighted average grant-date fair value (in dollars per share) | $ / shares	$ 4.85
Granted (in shares) | shares	12,050,644
Granted, weighted average grant-date fair value (in dollars per share) | $ / shares	$ 0.52
Vested (in shares) | shares	(2,666,468)
Vested, weighted average grant-date fair value (in dollars per share) | $ / shares	$ 3.21
Forfeited (in shares) | shares	(3,970,751)
Forfeited, weighted average grant-date fair value (in dollars per share) | $ / shares	$ 2.23
Nonvested (in shares) | shares	9,636,448
Nonvested, weighted average grant-date fair value (in dollars per share) | $ / shares	$ 0.96