Note 6 - Stockholders' Equity and Stock-based Compensation - Summary of Time-based Option Activity (Details) - Time-based Options [Member] - $ / shares	3 Months Ended	12 Months Ended
	Mar. 31, 2024	Dec. 31, 2023
Options balances, number of shares (in shares)	6,141,906
Options balances, weighted average exercise price (in dollars per share)	$ 10.48
Options balances, weighted average remaining life (Year)	7 years 18 days	7 years 25 days
Options granted, number of shares (in shares)	500,000
Options granted, weighted average exercise price (in dollars per share)	$ 8.98
Options exercised, number of shares (in shares)	0
Options exercised, weighted average exercise price (in dollars per share)	$ 0
Options canceled, number of shares (in shares)	(1,125)
Options canceled, weighted average exercise price (in dollars per share)	$ 16.6
Options expired, number of shares (in shares)	(1,500)
Options expired, weighted average exercise price (in dollars per share)	$ 17.01
Options balances, number of shares (in shares)	6,639,281	6,141,906
Options balances, weighted average exercise price (in dollars per share)	$ 10.36	$ 10.48
Options exercisable, number of shares (in shares)	3,580,866
Options exercisable, weighted average exercise price (in dollars per share)	$ 14.31
Options exercisable, weighted average remaining life (Year)	5 years 1 month 24 days