Marketable Securities - (Tables)

6 Months Ended

Jun. 27, 2020

Schedule of Marketable Securities by Category

At June 27, 2020 and December 31, 2019, marketable securities are categorized as follows:

	Amortized Cost		Gross Unrealized Holding Gains		Gross Unrealized Holding Losses		Fair Value
June 27, 2020
Municipal notes and bonds	$	64,366	$	235	$	2	$	64,599
U.S. treasury securities		4,996		—		—		4,996
Asset-backed securities		15,479		78		—		15,557
Certificates of deposit		35,798		18		17		35,799
Commercial paper		26,474		19		2		26,491
Corporate bonds		35,022		211		2		35,231
Total marketable securities	$	182,135	$	561	$	23	$	182,673
December 31, 2019
Municipal notes and bonds	$	80,926	$	188	$	6	$	81,108
Asset-backed securities		10,767		12		—		10,779
Certificates of deposit		30,500		7		—		30,507
Commercial paper		30,707		1		—		30,708
Corporate bonds		36,409		52		—		36,461
Total marketable securities	$	189,309	$	260	$	6	$	189,563

Schedule of Amortized Cost and Estimated Fair Value of Marketable Securities Classified by Maturity Date

The amortized cost and estimated fair value of marketable securities classified by the maturity date listed on the security, regardless of the Condensed Consolidated Balance Sheets classification, is as follows at June 27, 2020 and December 31, 2019:

	June 27, 2020				December 31, 2019
	Amortized Cost		Fair Value		Amortized Cost		Fair Value
Due within one year	$	144,394	$	144,797	$	152,649	$	152,852
Due after one through five years		37,741		37,876		36,660		36,711
Due after five through ten years		—		—		—		—
Due after ten years		—		—		—		—
Total marketable securities	$	182,135	$	182,673	$	189,309	$	189,563

Summary of Estimated Fair Value and Gross Unrealized Holding Losses of Marketable Securities in Unrealized Loss Position

The following table summarizes the estimated fair value and gross unrealized holding losses of marketable securities, aggregated by investment instrument and period of time in an unrealized loss position, at June 27, 2020 and December 31, 2019:

	In Unrealized Loss Position For Less Than 12 Months				In Unrealized Loss Position For Greater Than 12 Months
	Fair Value		Gross Unrealized Losses		Fair Value		Gross Unrealized Losses
June 27, 2020
Municipal notes and bonds	$	7,280	$	2	$	—	$	—
Asset-backed securities		3,049		1		—		—
Certificates of deposit		14,983		17		—		—
Commercial paper		5,498		1		—		—
Corporate bonds		4,277		2		—		—
Total	$	35,087	$	23	$	—	$	—
December 31, 2019
Municipal notes and bonds	$	14,166	$	6	$	—	$	—
Total	$	14,166	$	6	$	—	$	—