Note 4 - Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2021

Notes Tables

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

	December 31, 2021
	Quoted Prices in
	Active Markets for		Direct or Indirect
	Identical Assets		Observable
	(Level 1)		Inputs (Level 2)		Total
Assets
Cash equivalents:
Money market funds	$	37,023	$	—	$	37,023
Total cash equivalents		37,023		—		37,023
Restricted cash:
Money market funds		557		—		557
Total assets measured at fair value	$	37,580	$	—	$	37,580

	December 31, 2020
	Quoted Prices in
	Active Markets for		Direct or Indirect
	Identical Assets		Observable
	(Level 1)		Inputs (Level 2)		Total
Assets
Cash equivalents:
Money market funds	$	6,114	$	—	$	6,114
Total cash equivalents		6,114		—		6,114
Restricted cash:
Money market funds		337		—		337
Total assets measured at fair value	$	6,451	$	—	$	6,451