Note 3 - Fair Value Measurements (Tables)

3 Months Ended

Mar. 31, 2019

Notes Tables

Fair Value, Assets Measured on Recurring Basis [Table Text Block]

	As of March 31, 2019
	Quoted Prices in Active Markets (Level 1)		Significant Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Total
Assets
Cash equivalents	$	15,378	$	-	$	-	$	15,378
Total	$	15,378	$	-	$	-	$	15,378

	As of December 31, 2018
	Quoted Prices in Active Markets (Level 1)		Significant Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Total
Assets
Cash equivalents	$	18,353	$	-	$	-	$	18,353
Government securities		2,496		-		-		2,496
Total	$	20,849	$	-	$	-	$	20,849

Available-for-sale Securities [Table Text Block]

	Amortized Cost		Unrealized Gains		Unrealized Losses		Fair Value
March 31, 2019
Government securities
(Due within 1 year)	$	-	$	-	$	-	$	-
	$	-	$	-	$	-	$	-
December 31, 2018
Government securities
(Due within 1 year)	$	2,496	$	-	$	-	$	2,496
	$	2,496	$	-	$	-	$	2,496