Note 5 - Fair Value Measurements (Tables)

9 Months Ended

Sep. 30, 2016

Notes Tables

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

			Fair Value Measurements at Reporting Date Using
	September 30, 2016		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Cash equivalents:
Money market funds	$	67,299	$	-	$	67,299	$	-
Investments:
Bank certificates of deposit	$	22,250	$	-	$	22,250	$	-

			Fair Value Measurements at Reporting Date Using
	December 31, 2015		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Cash equivalents:
Money market funds	$	61,385	$	-	$	61,385	$	-
Bank certificates of deposit		250		-		250		-
Total cash equivalents	$	61,635	$	-	$	61,635	$	-
Investments:
Corporate debt securities	$	2,001	$	-	$	2,001	$	-
Bank certificates of deposit		25,750		-		25,750		-
Total investments	$	27,751	$	-	$	27,751	$	-