Note 8 - Stock-based Compensation - RSU Stock-based Payment Awards (Details) - Restricted Stock Units (RSUs) [Member]	12 Months Ended
	Dec. 31, 2021 $ / shares shares
Balance at January 1, 2022 (in shares) | shares	5,509
Balance at January 1, 2022 (in dollars per share) | $ / shares	$ 34.78
Vested(1) (in shares) | shares	(1,857)	[1]
Vested(1) (in dollars per share) | $ / shares	$ 31.41	[1]
Outstanding at December 31, 2022 (in shares) | shares	3,652
Outstanding at December 31, 2022 (in dollars per share) | $ / shares	$ 36.49

[1] The RSUs vested during the year ended December 31, 2022 were settled on a hybrid basis. The Company withheld 685 shares of common stock and, in lieu of delivering such shares, paid the RSU holder an amount in cash equal to the fair market value of such shares on the vesting date, representing the holder's approximate tax liability associated with the vesting.