Note 11 - Benefit Plans - Activity Related to Outstanding Stock Options (Details) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2023 USD ($) $ / shares shares
Beginning balance outstanding, number of options (in shares) | shares	15,260,297
Beginning balance outstanding, weighted average exercise price per share (in dollars per share) | $ / shares	$ 2.98
Outstanding, weighted average remaining term (Year)	7 years 3 months 10 days
Outstanding, intrinsic value | $	$ 2,348
Granted, number of options (in shares) | shares	7,053,200
Granted, weighted average exercise price per share (in dollars per share) | $ / shares	$ 0.92
Granted, weighted average remaining term (Year)	9 years 5 months 19 days
Forfeited, number of options (in shares) | shares	(467,109)
Forfeited, weighted average exercise price per share (in dollars per share) | $ / shares	$ 5.45
Ending balance outstanding, number of options (in shares) | shares	21,846,388
Ending balance outstanding, weighted average exercise price per share (in dollars per share) | $ / shares	$ 2.26
Outstanding, intrinsic value | $	$ 302
Vested and exercisable, number of options (in shares) | shares	11,717,679
Vested and exercisable, weighted average exercise price per share (in dollars per share) | $ / shares	$ 2.58
Vested and exercisable, weighted average remaining term (Year)	5 years 10 months 2 days
Vested and exercisable, intrinsic value | $	$ 302
Vested, exercisable and expected to vest, number of options (in shares) | shares	21,846,388
Vested, exercisable and expected to vest, weighted average exercise price per share (in dollars per share) | $ / shares	$ 2.26
Vested, exercisable or expected to vest, weighted average remaining term (Year)	7 years 3 months 10 days
Vested, exercisable or expected to vest, intrinsic value | $	$ 302