Investments (Tables)

12 Months Ended

Dec. 27, 2014

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 December 27, 2014 and December 28, 2013 (in thousands):

	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value
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
December 28, 2013
Money market investments	$	2,499	$	—	$	—	$	2,499
Asset-backed securities		4,350		19		72		4,297
Corporate bonds and direct obligations of government agencies		76,786		783		370		77,199
U.S. Treasury obligations		18,524		31		13		18,542
Total	$	102,159	$	833	$	455	$	102,537

Schedule of Unrealized Loss on Available for Sale Investments

For those available-for-sale investments with unrealized losses at December 27, 2014 and December 28, 2013, 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
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
December 28, 2013
Asset-backed securities	$	3,429	$	72	$	—	$	—	$	3,429	$	72
Corporate bonds and direct obligations of government agencies		22,169		370		—		—		22,169		370
U.S. Treasury obligations		757		13		—		—		757		13
Total	$	26,355	$	455	$	—	$	—	$	26,355	$	455