Investments (Tables)

9 Months Ended

Sep. 25, 2021

Amortized Cost and Fair Value of Available-for-Sale Investments

The amortized cost and fair values of available-for-sale investments are as follows at September 25, 2021 and December 26, 2020 (in thousands):

			Gross		Gross
	Amortized Cost		Unrealized Gains		Unrealized Losses		Fair Value
September 25, 2021
Money market investments	$	12,736	$	—	$	—	$	12,736
Asset-backed securities		18,899		4		63		18,840
Corporate bonds and direct obligations of government agencies		136,854		2,209		259		138,804
U.S. Treasury obligations		2,341		80		—		2,421
Total	$	170,830	$	2,293	$	322	$	172,801
December 26, 2020
Money market investments	$	17,867	$	—	$	—	$	17,867
Asset-backed securities		567		—		26		541
Corporate bonds and direct obligations of government agencies		98,241		3,551		72		101,720
U.S. Treasury obligations		2,338		125		—		2,463
Total	$	119,013	$	3,676	$	98	$	122,591

Schedule of Unrealized Loss on Available-for-Sale Investments

For those available-for-sale investments with unrealized losses at September 25, 2021 and December 26, 2020, the following table summarizes the duration of the unrealized loss (in thousands):

	Less than 12 months				12 months or longer				Total
	Fair Value		Unrealized Loss		Fair Value		Unrealized Loss		Fair Value		Unrealized Loss
September 25, 2021
Asset-backed securities	$	12,714	$	63	$	—	$	—	$	12,714	$	63
Corporate bonds and direct obligations of government agencies		49,442		259		—		—		49,442		259
Total	$	62,156	$	322	$	—	$	—	$	62,156	$	322
December 26, 2020
Asset-backed securities	$	541	$	26	$	—	$	—	$	541	$	26
Corporate bonds and direct obligations of government agencies		2,681		72		—		—		2,681		72
Total	$	3,222	$	98	$	—	$	—	$	3,222	$	98