Note 5 - Stock-based Compensation - Stock Option Activity (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2024	Dec. 31, 2023
Options outstanding, shares (in shares)	1
Options outstanding, weighted average exercise price (in dollars per share)	$ 22.15
Options outstanding, weighted average grant date fair value (in dollars per share)	$ 0	$ 0
Granted, shares (in shares)	0
Granted, weighted average exercise price (in dollars per share)	$ 0
Granted, weighted average grant date fair value (in dollars per share)	$ 0
Exercised, shares (in shares)	0
Exercised, weighted average exercise price (in dollars per share)	$ 0
Exercised, weighted average grant date fair value (in dollars per share)	$ 0
Forfeited or expired, shares (in shares)	0
Forfeited or expired, weighted average exercise price (in dollars per share)	$ 0
Forfeited or expired, weighted average grant date fair value (in dollars per share)	$ 0
Options outstanding, shares (in shares)	1
Options outstanding,, weighted average exercise price (in dollars per share)	$ 22.15
Options outstanding, aggregate intrinsic value	$ 6
Options exercisable, shares (in shares)	1
Options exercisable, weighted average exercise price (in dollars per share)	$ 22.15
Options exercisable, aggregate intrinsic value	$ 6
Options unvested, shares (in shares)	0