Note 6 - Stock-based Compensation and Option Plans - Stock Option Activity (Details) - Share-Based Payment Arrangement, Option [Member] - $ / shares shares in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Balance (in shares)	55	196
Balance, weighted average exercise price (in dollars per share)	$ 53.79	$ 49.69
Forfeited/Expired (in shares)	(55)	(141)
Forfeited/Expired, weighted average exercise price (in dollars per share)	$ 53.79	$ 48.11
Balance (in shares)	0	55
Balance, weighted average exercise price (in dollars per share)	$ 0	$ 53.79
Options outstanding, intrinsic value per share (in dollars per share)	$ 0
Exercisable at end of year (in shares)	0
Exercisable, weighted average exercise price (in dollars per share)	$ 0
Exercisable, intrinsic value per share (in dollars per share)	$ 0