Note 4 - Fair Value Measurements (Tables)

6 Months Ended

Jun. 30, 2022

Notes Tables

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

	Fair Value Measurements as of June 30, 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	$	—	$	72,768	$	—	$	72,768
Commercial paper		22,661		—		—		22,661
Certificates of deposit		—		5,654		—		5,654
Asset-backed securities		—		4,697		—		4,697
Money market funds (cash equivalents)		11,301		—		—		11,301
Total assets	$	33,962	$	83,119	$	—	$	117,081

	Fair Value Measurements as of December 31, 2021 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
Money market funds (cash equivalents)	$	130,005	$	—	$	—	$	130,005
Total assets	$	130,005	$	—	$	—	$	130,005