Note 5 - Financial Instruments Measured at Fair Value (Tables)

6 Months Ended

Jun. 27, 2020

Notes Tables

Available-for-sale Securities [Table Text Block]

	June 27, 2020
			Gross		Gross		Estimated
	Amortized		Unrealized		Unrealized		Fair
	Cost		Gains		Losses (1)		Value
Foreign government security	$	920	$	-	$	-	$	920

	December 28, 2019
			Gross		Gross		Estimated
	Amortized		Unrealized		Unrealized		Fair
	Cost		Gains		Losses (1)		Value
Foreign government security	$	904	$	-	$	-	$	904

Investments Classified by Contractual Maturity Date [Table Text Block]

	June 27, 2020				December 28, 2019
	Amortized		Estimated		Amortized		Estimated
	Cost		Fair Value		Cost		Fair Value
Due in one year or less	$	920	$	920	$	-	$	-
Due after one year through three years		-		-		904		904
	$	920	$	920	$	904	$	904

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

	Fair value measurements at June 27, 2020 using:
							Total estimated
	Level 1		Level 2		Level 3		fair value
Cash	$	112,531	$	-	$	-	$	112,531
Money market funds		-		50,197		-		50,197
Foreign government security		-		920		-		920
	$	112,531	$	51,117	$	-	$	163,648

	Fair value measurements at December 28, 2019 using:
							Total estimated
	Level 1		Level 2		Level 3		fair value
Cash	$	147,523	$	-	$	-	$	147,523
Money market funds		-		7,671		-		7,671
Foreign government security		-		904		-		904
	$	147,523	$	8,575	$	-	$	156,098