Note 4 - Stock-based Compensation - Summary of Option Exercise Prices by Grouped Ranges (Details) shares in Thousands	12 Months Ended
	Dec. 31, 2022 $ / shares shares
Lower Range Limit (in dollars per share)	$ 15.36
Upper Range Limit (in dollars per share)	$ 39.54
Shares Outstanding (in shares) | shares	51
Outstanding, Weighted Average Remaining Contractual Term (Year)	9 months 7 days
Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 39.14
Shares Exercisable (in shares) | shares	51
Exercisable, Weighted Average Remaining Contractual Term (Year)	9 months 7 days
Exercisable, Weighted Average Exercise Price (in dollars per share)	$ 39.14
Range 1 [Member]
Lower Range Limit (in dollars per share)	15.36
Upper Range Limit (in dollars per share)	$ 24.99
Shares Outstanding (in shares) | shares	1
Outstanding, Weighted Average Remaining Contractual Term (Year)	7 years 10 months 6 days
Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 22.15
Shares Exercisable (in shares) | shares	1
Exercisable, Weighted Average Remaining Contractual Term (Year)	7 years 10 months 6 days
Exercisable, Weighted Average Exercise Price (in dollars per share)	$ 22.15
Range 2 [Member]
Lower Range Limit (in dollars per share)	25.01
Upper Range Limit (in dollars per share)	34.99
Range 3 [Member]
Lower Range Limit (in dollars per share)	35.01
Upper Range Limit (in dollars per share)	$ 39.54
Shares Outstanding (in shares) | shares	50
Outstanding, Weighted Average Remaining Contractual Term (Year)	7 months 9 days
Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 39.54
Shares Exercisable (in shares) | shares	50
Exercisable, Weighted Average Remaining Contractual Term (Year)	7 months 9 days
Exercisable, Weighted Average Exercise Price (in dollars per share)	$ 39.54