Note 10 - Equity Incentive Plans - Summary of Stock Option Transactions (Details) - $ / shares	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Shares available for grant, balance (in shares)	5,685,806	12,074,692
Number of options outstanding, beginning balance (in shares)	17,938,726	14,725,261
Weighted average exercise price, balance (in dollars per share)	$ 2.9	$ 4.48
Shares available for grant, granted (in shares)	(7,258,980)	(10,631,320)
Number of options outstanding, granted (in shares)	5,309,437	7,399,849
Weighted average exercise price, granted (in dollars per share)	$ 1.12	$ 0.78
Number of options outstanding, exercised (in shares)	(38,030)	(54,720)
Weighted average exercise price, exercised (in dollars per share)	$ 0.78	$ 0.31
Shares available for grant, forfeited (in shares)	1,944,001	2,444,486
Number of options outstanding, forfeited (in shares)	(1,483,826)	(2,139,887)
Weighted average exercise price, forfeited (in dollars per share)	$ 2.29	$ 5
Shares available for grant, canceled (in shares)	1,279,297	1,797,948
Number of options outstanding, canceled (in shares)	(1,321,068)	(1,991,777)
Weighted average exercise price, canceled (in dollars per share)	$ 2.87	$ 4.51
Shares available for grant, balance (in shares)	19,650,124	5,685,806
Number of options outstanding, balance (in shares)	20,405,239	17,938,726
Weighted average exercise price, balance (in dollars per share)	$ 2.49	$ 2.9
The 2024 Inducement Award Plan [Member]
Authorized (in shares)	3,000,000
The 2019 Plan [Member]
Authorized (in shares)	15,000,000
Restricted Stock Units (RSUs) [Member]
Number of RSUs outstanding (in shares)	2,126,373	808,310
Balance, Weighted average grant date fair value (in dollars per share)	$ 1.37	$ 3.57
Number of RSUs outstanding, granted (in shares)	1,949,543	3,231,471
Granted, Weighted average grant date fair value (in dollars per share)	$ 1.13	$ 0.78
Number of RSUs outstanding, forfeite (in shares)	(460,175)	(304,599)
Forfeited, Weighted average grant date fair value (in dollars per share)	$ 1.41	$ 2.42
Number of RSUs outstanding (in shares)	3,016,481	2,126,373
Balance, Weighted average grant date fair value (in dollars per share)	$ 1.19	$ 1.37
Number of RSUs outstanding, release (in shares)	(599,260)
Released, Weighted average grant date fair value (in dollars per share)	$ 1.48