Investments (Tables)

6 Months Ended

Jun. 26, 2021

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

			Gross		Gross
	Amortized Cost		Unrealized Gains		Unrealized Losses		Fair Value
June 26, 2021
Money market investments	$	24,649	$	—	$	—	$	24,649
Asset-backed securities		564		—		—		564
Corporate bonds and direct obligations of government agencies		142,542		2,602		238		144,906
U.S. Treasury obligations		2,340		88		—		2,428
Total	$	170,095	$	2,690	$	238	$	172,547
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 June 26, 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
June 26, 2021
Corporate bonds and direct obligations of  government agencies	$	52,720	$	238	$	—	$	—	$	52,720	$	238
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