Note 7 - Financial Instruments Measured at Fair Value (Tables)

12 Months Ended

Dec. 29, 2018

Notes Tables

Available-for-sale Securities [Table Text Block]

	At December 29, 2018
			Gross		Gross		Estimated
	Amortized		Unrealized		Unrealized		Fair
	Cost		Gains		Losses (1)		Value
Foreign government security	$	560	$	-	$	-	$	560

	At December 30, 2017
			Gross		Gross		Estimated
	Amortized		Unrealized		Unrealized		Fair
	Cost		Gains		Losses (1)		Value
Corporate debt securities (2)	$	12,784	$	1	$	6	$	12,779
U.S. treasury securities		7,935		-		4		7,931
Foreign government security		619		-		-	$	619
	$	21,338	$	1	$	10	$	21,329

Investments Classified by Contractual Maturity Date [Table Text Block]

	Amortized		Estimated
(in thousands)	Cost		Fair Value
Due after one year through three years	$	560	$	560

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

	Fair value measurements at December 29, 2018 using:
							Total estimated
	Level 1		Level 2		Level 3		fair value
Cash	$	144,696	$	-	$	-	$	144,696
Foreign government security		-		560		-		560
Money market funds		-		19,764		-		19,764
	$	144,696	$	20,324	$	-	$	165,020

	Fair value measurements at December 30, 2017 using:
							Total estimated
	Level 1		Level 2		Level 3		fair value
Cash	$	100,850	$	-	$	-	$	100,850
Money market funds		-		22,205		-		22,205
Corporate debt securities		-		22,014		-		22,014
U.S. treasury securities		-		8,431		-		8,431
Government-sponsored enterprise securities		-		1,496		-		1,496
Foreign government security		-		619		-		619
	$	100,850	$	54,765	$	-	$	155,615