Note 9 - Equity Incentive Plans - Summary of Stock Option Transactions (Details) - $ / shares	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024
Shares available for grant, balance (in shares)	19,650,124
Number of options outstanding, beginning balance (in shares)	20,405,239
Weighted average exercise price, balance (in dollars per share)	$ 2.49
Shares available for grant, granted (in shares)	(10,920,800)
Number of options outstanding, granted (in shares)	6,840,800
Weighted average exercise price, granted (in dollars per share)	$ 0.52
Number of options outstanding, exercised (in shares)	(3,625)	(8,865)
Weighted average exercise price, exercised (in dollars per share)	$ 0.78
Shares available for grant, forfeited (in shares)	422,820
Number of options outstanding, forfeited (in shares)	(260,844)
Weighted average exercise price, forfeited (in dollars per share)	$ 1.57
Shares available for grant, canceled (in shares)	61,942
Number of options outstanding, canceled (in shares)	(61,942)
Weighted average exercise price, canceled (in dollars per share)	$ 3.38
Shares available for grant, balance (in shares)	9,214,086
Number of options outstanding, balance (in shares)	26,919,628
Weighted average exercise price, balance (in dollars per share)	$ 1.99
Restricted Stock Units (RSUs) [Member]
Number of RSUs outstanding (in shares)	3,016,481
Balance, Weighted average grant date fair value (in dollars per share)	$ 1.19
Number of RSUs outstanding, granted (in shares)	4,080,000
Granted, Weighted average grant date fair value (in dollars per share)	$ 0.51
Number of RSUs outstanding, release (in shares)	(718,282)
Released, Weighted average grant date fair value (in dollars per share)	$ 1.13
Number of RSUs outstanding, forfeite (in shares)	(161,976)
Forfeited, Weighted average grant date fair value (in dollars per share)	$ 1.26
Number of RSUs outstanding (in shares)	6,216,223
Balance, Weighted average grant date fair value (in dollars per share)	$ 0.75