Fair Value Measurements (Tables)

3 Months Ended

Mar. 28, 2015

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 March 28, 2015										As of December 27, 2014
	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	$	39,633	$	—		$	—	$	39,633		$	21,478	$	—		$	—	$	21,478
Certificates of deposit	—		9,465			—		9,465			—		8,060			—		8,060
Commercial paper	—		21,690			—		21,690			—		46,072			—		46,072
Corporate bonds	—		223,238			—		223,238			—		235,285			—		235,285
U.S. agency notes	—		14,508			—		14,508			—		—			—		—
U.S. treasuries	16,014		—			—		16,014			14,810		—			—		14,810
Foreign currency exchange forward contracts	—		—			—		—			—		—			—		—
Total assets	$	55,647	$	268,901		$	—	$	324,548		$	36,288	$	289,417		$	—	$	325,705
Liabilities
Foreign currency exchange forward contracts	$	—	$	(117	)	$	—	$	(117	)	$	—	$	(64	)	$	—	$	(64	)

Investments at Fair Value

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

	March 28, 2015
	Adjusted Amortized Cost		Gross Unrealized Gains		Gross Unrealized  Losses			Fair Value
Money market funds	$	39,633	$	—	$	—		$	39,633
Certificates of deposit	9,460		5		—			9,465
Commercial paper	21,691		—		(1		)	21,690
Corporate bonds	223,425		12		(199		)	223,238
U.S. agency notes	14,507		5		(4		)	14,508
U.S. treasuries	16,009		9		(4		)	16,014
Total available-for-sale investments	$	324,725	$	31	$	(208	)	$	324,548

	December 27, 2014
	Adjusted Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
Money market funds	$	21,478	$	—	$	—		$	21,478
Certificates of deposit	8,060		—		—			8,060
Commercial paper	46,073		—		(1		)	46,072
Corporate bonds	235,713		2		(430		)	235,285
U.S. treasuries	14,825		1		(16		)	14,810
Total available-for-sale investments	$	326,149	$	3	$	(447	)	$	325,705