Note 4 - Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2020

Notes Tables

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

	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
Corporate commercial paper		-		-		-
Corporate debt		-		-		-
Total cash equivalents		6,114		-		6,114
Restricted cash:
Money market funds		337		-		337
Short-term investments:
Corporate commercial paper		-		-		-
Corporate debt		-		-		-
Total short-term investments		-		-		-
Total assets measured at fair value	$	6,451	$	-	$	6,451

	December 31, 2019
	Quoted Prices in
	Active Markets for		Direct or Indirect
	Identical Assets		Observable
	(Level 1)		Inputs (Level 2)		Total
Assets
Cash equivalents:
Money market funds	$	1,871	$	-	$	1,871
Corporate commercial paper		-		999		999
Corporate debt		-		750		750
Total cash equivalents		1,871		1,749		3,620
Restricted cash:
Money market funds		600		-		600
Short-term investments:
Corporate commercial paper		-		748		748
Corporate debt		-		1,501		1,501
Total short-term investments		-		2,249		2,249
Total assets measured at fair value	$	2,471	$	3,998	$	6,469