Note 4 - Fair Value of Financial Instruments (Tables)

12 Months Ended

Dec. 31, 2023

Notes Tables

Fair Value, Assets Measured on Recurring Basis [Table Text Block]

	Level 1		Level 2		Level 3		Total
December 31, 2023
Financial assets:
Money market funds	$	31,403	$	—	$	—	$	31,403
U.S. Treasury securities		—		4,958		—		4,958
Total assets	$	31,403	$	4,958	$	—	$	36,361

	Level 1		Level 2		Level 3		Total
December 31, 2022
Financial assets:
Money market funds	$	30,834	$	—	$	—	$	30,834
U.S. Treasury securities		—		41,542		—		41,542
Corporate securities		—		8,162		—		8,162
Total assets	$	30,834	$	49,704	$	—	$	80,538