Note 6 - 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 Using
			Quoted Prices		Significant
			in Active		Other
	Balance as of		Markets for		Observable
	June 30,		Identical Assets		Inputs
	2022		(Level 1)		(Level 2)
Assets:
Cash equivalents
US government	$	29,357	$	29,357	$	—
Commercial paper		23,042		—		23,042
Total cash equivalents		52,399		29,357		23,042
Marketable securities
US government		25,023		25,023		—
Corporate bonds		2,555		—		2,555
Commercial paper		4,143		—		4,143
Total marketable securities		31,721		25,023		6,698
Total assets at fair value	$	84,120	$	54,380	$	29,740

			Fair Value Measurements Using
			Quoted Prices		Significant
			in Active		Other
	Balance as of		Markets for		Observable
	December 31,		Identical Assets		Inputs
	2021		(Level 1)		(Level 2)
Assets:
Cash equivalents
Money market funds	$	21,402	$	21,402	$	—
Marketable securities
US government		19,307		19,307		—
Corporate bonds		8,652		—		8,652
Commercial paper		14,492		—		14,492
Certificates of deposit		3,003		—		3,003
Total marketable securities		45,454		19,307		26,147
Total assets at fair value	$	66,856	$	40,709	$	26,147