Fair Value Measurements and Disclosures (Tables)

12 Months Ended

Dec. 31, 2016

Assets and liabilities measurements at estimated fair value on recurring basis excluding accrued interest components

The following tables present the Company’s assets and liabilities measured at estimated fair value on a recurring basis, excluding accrued interest components, categorized in accordance with the fair value hierarchy (in thousands), as of the following dates:

	December 31, 2016								December 26, 2015
	Fair Value Measurements Using Input Types								Fair Value Measurements Using Input Types
	Level 1		Level 2		Level 3		Total		Level 1		Level 2		Level 3		Total
Assets:
Cash equivalents:
Money market funds	$	959	$	—	$	—	$	959	$	590	$	—	$	—	$	590
Commercial paper and corporate debt securities		—		2,499		—		2,499		—		4,568		—		4,568
Total cash equivalents	$	959	$	2,499	$	—	$	3,458	$	590	$	4,568	$	—	$	5,158

Marketable securities:
U.S. Treasury, U.S. Government and U.S. Government agency debt securities		—		17,072		—		17,072		4,401		20,164		—		24,565
Certificate of deposits		—		23,019		—		23,019		—		—		—		—
Commercial paper		—		22,402		—		22,402		—		1,884		—		1,884
Municipal securities and corporate debt securities		—		14,943		—		14,943		—		18,482		—		18,482
Asset backed securities		—		5,463		—		5,463		—		—		—		—
Total marketable securities	$	—	$	82,899	$	—	$	82,899	$	4,401	$	40,530	$	—	$	44,931

Total⁽¹⁾	$	959	$	85,398	$	—	$	86,357	$	4,991	$	45,098	$	—	$	50,089

Liabilities:
Contingent consideration payable	$	—	$	—	$	—	$	—	$	—	$	—	$	1,490	$	1,490

⁽¹⁾	Excludes $43.6 million and $33.0 million held in operating accounts as of December 31, 2016 and December 26, 2015, respectively.

Fair value measurement on recurring basis, unobservable input reconciliation

Changes in Level 3 liabilities	(in thousands)
Fair value at December 27, 2014	$	2,397
Payments made to Zygo Corporation		(851	)
Change in fair value included in earnings		(56	)
Fair value at December 26, 2015		1,490
Payments made to Zygo Corporation		(315	)
Change in fair value included in earnings		(1,175	)
Fair value at December 31, 2016	$	—

Outstanding derivative instruments

The following table summarizes the Company’s outstanding derivative instruments on a gross basis:

	As of December 31, 2016		As of December 26, 2015
	Notional Principal		Notional Principal
	(in millions)		(in millions)
Undesignated Hedges:
Forward Foreign Currency Contracts	$	13.9	$	30.5