Fair Value Measurements and Disclosures (Tables)

3 Months Ended

Mar. 26, 2016

Fair Value Disclosures [Abstract]

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:

	March 26, 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	$	1,075	$	—	$	—	$	1,075	$	590	$	—	$	—	$	590
Commercial paper and corporate debt    securities		—		4,452		—		4,452		—		4,568		—		4,568
Total cash equivalents	$	1,075	$	4,452	$	—	$	5,527	$	590	$	4,568	$	—	$	5,158
Marketable securities:
U.S. Treasury, U.S. Government and U.S.    Government agency debt securities		6,973		23,227		—		30,200		4,401		20,164		—		24,565
Commercial paper, municipal securities    and corporate debt securities		—		14,473		—		14,473		—		20,366		—		20,366
Total marketable securities	$	6,973	$	37,700	$	—	$	44,673	$	4,401	$	40,530	$	—	$	44,931
Total(1)	$	8,048	$	42,152	$	—	$	50,200	$	4,991	$	45,098	$	—	$	50,089
Liabilities:
Contingent consideration payable	$	—	$	—	$	1,461	$	1,461	$	—	$	—	$	1,490	$	1,490

⁽¹⁾ Excludes $33.1 million and $33.0 million held in operating accounts as of March 26, 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 26, 2015	$	1,490
Payments made to Zygo Corporation		(84	)
Change in fair value included in earnings		55
Fair value at  March 26, 2016	$	1,461

Outstanding derivative instruments

The following table summarizes the Company’s outstanding derivative instruments on a gross basis as of March 26, 2016:

	Notional Principal
	(in millions)
Undesignated Hedges:
Forward Foreign Currency Contracts	$	23.3