Investments (Tables)

3 Months Ended

Mar. 28, 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 March 28, 2015 and December 27, 2014 (in thousands):

	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value
March 28, 2015
Money market investments	$	1,060	$	—	$	—	$	1,060
Asset-backed securities		5,078		2		22		5,058
Corporate bonds and direct obligations of government agencies		77,823		614		87		78,350
U.S. Treasury obligations		19,651		13		4		19,660
Total	$	103,612	$	629	$	113	$	104,128
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 March 28, 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
March 28, 2015
Asset-backed securities	$	895	$	6	$	2,468	$	16	$	3,363	$	22
Corporate bonds and direct obligations of government agencies		2,561		59		6,707		28		9,268		87
U.S. Treasury obligations		4,903		3		766		1		5,669		4
Total	$	8,359		68	$	9,941	$	45	$	18,300	$	113
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