CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS (Unaudited) - USD ($) $ in Thousands	3 Months Ended
Mar. 30, 2019	Mar. 31, 2018
Statement of Comprehensive Income [Abstract]
Net loss	$ (121,601)	$ (26,280)
Other comprehensive income (loss), net of tax:
Change in unrealized gain (loss) on available-for-sale investments	65	(125)
Foreign currency translation adjustment	(5,557)	(4,816)
Actuarial gain on pension liabilities	78	0
Net change in accumulated other comprehensive loss	(5,414)	(4,941)
Comprehensive loss	$ (127,015)	$ (31,221)

Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income, attributable to parent entity. Excludes changes in equity resulting from investments by owners and distributions to owners.

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