Note 10 - Stock-based Compensation - Restricted Stock Options (Details) - Restricted Stock [Member]	9 Months Ended
	Sep. 30, 2022 $ / shares shares
Restricted stock (in shares) | shares	343,782
Restricted stock, weighted-average grant date fair value (in dollars per share) | $ / shares	$ 111.79
Granted (in shares) | shares	312,270
Granted, weighted-average grant date fair value (in dollars per share) | $ / shares	$ 42.05
Restrictions lapsed (in shares) | shares	(120,606)
Restrictions lapsed, weighted-average grant date fair value (in dollars per share) | $ / shares	$ 104.99
Forfeited (in shares) | shares	(39,480)
Forfeited, weighted-average grant date fair value (in dollars per share) | $ / shares	$ 106.64
Restricted stock (in shares) | shares	495,966
Restricted stock, weighted-average grant date fair value (in dollars per share) | $ / shares	$ 69.95