Note 4 - Fair Value Measurements (Tables)

6 Months Ended

Jun. 30, 2020

Notes Tables

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

	June 30, 2020						December 31, 2019
	Quoted Prices in		Direct or				Quoted Prices in		Direct or
	Active Markets		Indirect				Active Markets		Indirect
	for Identical		Observable				for Identical		Observable
	Assets (Level 1)		Inputs (Level 2)		Total		Assets (Level 1)		Inputs (Level 2)		Total
Assets
Cash equivalents:
Money market funds	$	5,854	$	—	$	5,854	$	1,871	$	—	$	1,871
Corporate commercial paper		—		—		—		—		999		999
Corporate debt		—		—		—		—		750		750
Total cash equivalents		5,854		—		5,854		1,871		1,749		3,620
Restricted cash:
Money market funds		600		—		600		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	$	6,454	$	—	$	6,454	$	2,471	$	3,998	$	6,469