Note 3 - Fair Value Measurements (Tables)

6 Months Ended

Jun. 30, 2023

Notes Tables

Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block]

	Fair Value Measurements as of June 30, 2023 Using:
	Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Fair Value
Assets
Corporate bonds	$	—	$	48,645	$	—	$	48,645
Commercial paper		50,594		—		—		50,594
Certificates of deposit		—		26,483		—		26,483
U.S. government treasuries		14,778		—		—		14,778
Asset-backed securities		—		8,974		—		8,974
Cash equivalents		774		—		—		774
Total assets	$	66,146	$	84,102	$	—	$	150,248

	Fair Value Measurements as of December 31, 2022 Using:
	Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Fair Value
Assets
Corporate bonds	$	—	$	87,760	$	—	$	87,760
Commercial paper		37,682		—		—		37,682
Certificates of deposit		—		19,667		—		19,667
Asset-backed securities		—		6,554		—		6,554
Cash equivalents		9,438		—		—		9,438
Total assets	$	47,120	$	113,981	$	—	$	161,101