Investments (Tables)

9 Months Ended

Sep. 26, 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 September 26, 2015 and December 27, 2014 (in thousands):

	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value
September 26, 2015
Money market investments	$	9,754	$	—	$	—	$	9,754
Asset-backed securities		4,856		—		17		4,839
Corporate bonds and direct obligations of government agencies		73,783		372		93		74,062
U.S. Treasury obligations		19,647		10		1		19,656
Total	$	108,040	$	382	$	111	$	108,311
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 September 26, 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
September 26, 2015
Asset-backed securities	$	3,744	$	17	$	—	$	—	$	3,744	$	17
Corporate bonds and direct obligations of government agencies		15,759		54		4,093		39		19,852		93
U.S. Treasury obligations		4,074		1		—		—		4,074		1
Total	$	23,577	$	72	$	4,093	$	39	$	27,670	$	111
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