Investments (Tables)

6 Months Ended

Jun. 27, 2015

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 June 27, 2015 and December 27, 2014 (in thousands):

	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value
June 27, 2015
Money market investments	$	5,486	$	—	$	—	$	5,486
Asset-backed securities		5,039		—		29		5,010
Corporate bonds and direct obligations of government agencies		76,231		393		113		76,511
U.S. Treasury obligations		19,628		13		2		19,639
Total	$	106,384	$	406	$	144	$	106,646
December 27, 2014
Money market investments	$	1,729	$	—	$	—	$	1,729
Asset-backed securities		5,106		1		50		5,057
Corporate bonds and direct obligations of government agencies		76,964		491		284		77,171
U.S. Treasury obligations		19,507		14		9		19,512
Total	$	103,306	$	506	$	343	$	103,469

Schedule of Unrealized Loss on Available for Sale Investments

For those available-for-sale investments with unrealized losses at June 27, 2015 and December 27, 2014, 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 27, 2015
Asset-backed securities	$	5,010	$	29	$	—	$	—	$	5,010	$	29
Corporate bonds and direct obligations of government agencies		21,786		102		3,503		11		25,289		113
U.S. Treasury obligations		1,266		2		—		—		1,266		2
Total	$	28,062	$	133	$	3,503	$	11	$	31,565	$	144
December 27, 2014
Asset-backed securities	$	2,006	$	13	$	2,447	$	37	$	4,453	$	50
Corporate bonds and direct obligations of government agencies		19,354		135		11,373		149		30,727		284
U.S. Treasury obligations		6,992		1		760		8		7,752		9
Total	$	28,352	$	149	$	14,580	$	194	$	42,932	$	343