Note 6 - Equity Incentive Plans - Summary of Restricted Stock Shares Activity (Details)	6 Months Ended
	Jun. 30, 2023 $ / shares shares
Restricted Stock [Member]
Outstanding, shares (in shares) | shares	1,075
Outstanding, weighted average grant date fair value (in dollars per share) | $ / shares	$ 64.03
Granted , shares (in shares) | shares	0
Granted, weighted average grant date fair value (in dollars per share) | $ / shares	$ 0
Vested, shares (in shares) | shares	0
Vested, weighted average grant date fair value (in dollars per share) | $ / shares	$ 0
Forfeited, shares (in shares) | shares	0
Forfeited, weighted average grant date fair value (in dollars per share) | $ / shares	$ 0
Outstanding, shares (in shares) | shares	1,075
Outstanding, weighted average grant date fair value (in dollars per share) | $ / shares	$ 64.03
Restricted Stock Units (RSUs) [Member]
Outstanding, shares (in shares) | shares	0
Outstanding, weighted average grant date fair value (in dollars per share) | $ / shares	$ 0
Granted , shares (in shares) | shares	14,833
Granted, weighted average grant date fair value (in dollars per share) | $ / shares	$ 69.00
Vested, shares (in shares) | shares	0
Vested, weighted average grant date fair value (in dollars per share) | $ / shares	$ 0
Forfeited, shares (in shares) | shares	0
Forfeited, weighted average grant date fair value (in dollars per share) | $ / shares	$ 0
Outstanding, shares (in shares) | shares	14,833
Outstanding, weighted average grant date fair value (in dollars per share) | $ / shares	$ 69.00