Fair Value Measurements and Other-Than-Temporary Impairments (Tables)

9 Months Ended

Sep. 27, 2014

Fair Value Disclosures [Abstract]

Assets and Liabilities Measured at Fair Value on Recurring Basis

The following tables represent the Company’s fair value hierarchy for its assets and liabilities measured at fair value on a recurring basis (in thousands):

	As of September 27, 2014								As of December 28, 2013
	Fair Value Measured Using								Fair Value Measured Using
	Level 1		Level 2		Level 3		Total		Level 1		Level 2		Level 3		Total
Assets
Money market funds	$	15,369	$	—	$	—	$	15,369	$	51,749	$	—	$	—	$	51,749
Certificates of deposit	—		3,460		—		3,460		—		3,840		—		3,840
Commercial paper	—		83,838		—		83,838		—		85,860		—		85,860
Corporate bonds	—		202,804		—		202,804		—		150,595		—		150,595
U.S. treasuries	8,833		—		—		8,833		4,804		—		—		4,804
Foreign currency exchange forward contracts	—		—		—		—		—		29		—		29
Total assets	$	24,202	$	290,102	$	—	$	314,304	$	56,553	$	240,324	$	—	$	296,877
Liabilities
Foreign currency exchange forward contracts	$	—	$	32	$	—	$	32	$	—	$	26	$	—	$	26

Investments at Fair Value

Investments at fair value were as follows (in thousands):

	September 27, 2014
	Adjusted Amortized Cost		Gross Unrealized Gains		Gross Unrealized  Losses			Fair Value
Money market funds	$	15,369	$	—	$	—		$	15,369
Certificates of deposit	3,460		—		—			3,460
Commercial paper	83,838		2		(2		)	83,838
Corporate bonds	202,959		19		(174		)	202,804
U.S. treasuries	8,829		5		(1		)	8,833
Total available-for-sale investments	$	314,455	$	26	$	(177	)	$	314,304

	December 28, 2013
	Adjusted Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
Money market funds	$	51,749	$	—	$	—		$	51,749
Certificates of deposit	3,840		—		—			3,840
Commercial paper	85,870		2		(12		)	85,860
Corporate bonds	150,711		27		(143		)	150,595
U.S. treasuries	4,802		2		—			4,804
Total available-for-sale investments	$	296,972	$	31	$	(155	)	$	296,848

Schedule of Amortized Cost Cumulative Other Than Temporary Impairment Recognized in Earnings and Accumulated Other Comprehensive Loss

A roll-forward of amortized cost, cumulative other-than-temporary impairments ("OTTI") recognized in earnings and accumulated other comprehensive loss for the nine months ended September 28, 2013 were as follows (in thousands):

	Amortized Cost			Cumulative OTTI in Earnings			Unrealized Gain			OTTI Loss in Accumulated Other Comprehensive Loss			Accumulated Other Comprehensive Income (Loss)
Balance at December 29, 2012	$	2,707		$	(394	)	$	784		$	(618	)	$	166
Call on investments	(87		)	13			(25		)	20			(5		)
Investments sold	(2,620		)	381			(759		)	598			(161		)
Balance at September 28, 2013	$	—		$	—		$	—		$	—		$	—