Note 8 - Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2018

Notes Tables

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

	Balance as of		Fair value measurements
Description	December 31, 201 8		Level 1		Level 2		Level 3
Assets
Cash equivalents
Money market mutual funds	$	773	$	773		-		-
Short-term marketable securities and time deposits
U.S. GSE securities	$	1,785		-	$	1,785		-
Corporate debt securities	$	25,579		-	$	25,579		-
Long-term marketable securities
U.S. GSE securities	$	19,512		-	$	19,512		-
Corporate debt securities	$	50,896		-	$	50,896		-
Derivative liabilities	$	3		-	$	3		-

	Balance as of		Fair value measurements
Description	December 31, 201 7		Level 1		Level 2		Level 3
Assets
Cash equivalents
Money market mutual funds	$	2,998	$	2,998		-		-
Short-term marketable securities and time deposits
U.S. GSE securities	$	786		-	$	786		-
Corporate debt securities	$	18,430		-	$	18,430		-
Long-term marketable securities
U.S. GSE securities	$	21,258		-	$	21,258		-
Corporate debt securities	$	56,398		-	$	56,398		-