Note 2 - Fair Value of Financial Instruments (Tables)

3 Months Ended

Mar. 31, 2023

Notes Tables

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

March 31, 2023	Level 1		Level 2		Level 3		Total
Money market securities	$	4,698	$	—	$	—	$	4,698
Commercial paper		—		19,437		—		19,437
Federal agency notes		—		15,000		—		15,000
Corporate notes		—		1,986		—		1,986
Total	$	4,698	$	36,423	$	—	$	41,121

December 31, 2022	Level 1		Level 2		Level 3		Total
Money market securities	$	2,073	$	—	$	—	$	2,073
Commercial paper		—		35,468		—		35,468
Corporate notes		—		8,432		—		8,432
Federal agency notes		—		4,423		—		4,423
Total	$	2,073	$	48,323	$	—	$	50,396

Investments Classified by Contractual Maturity Date [Table Text Block]

	Maturities by Period
			Less than		1-5		5-10		More than
	Total		1 year		years		years		10 years
Cash equivalents and marketable securities	$	41,121	$	41,121	$	—	$	—	$	—