Basis of Presentation and Summary of Significant Accounting Policies New Accounting Standards (Details Textual) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 29, 2018	Sep. 29, 2018	Dec. 31, 2017	Dec. 30, 2017
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Retained earnings	$ 674,284	$ 674,284	$ 426,932	$ 341,003
Receivables, net	240,836	240,836		190,426
Contract assets	15,151	15,151		3,964
Current portion of deferred revenue	(329,168)	(329,168)		(336,297)
Accounts payable and accrued liabilities	$ 212,153	$ 212,153		$ 221,101
Percentage of revenue mix recognizable over time	90.00%	90.00%
Accounting Standards Update 2016-16
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Retained earnings			(8,349)
Accounting Standards Update 2014-09
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Retained earnings			91,640
Accounting Standards Update 2014-09 \| Initial application period cumulative effect adjustments
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Retained earnings	$ (87,726)	$ (87,726)	85,400
Receivables, net	(21,647)	(21,647)	47,300
Contract assets			4,000
Current portion of deferred revenue	(51,315)	(51,315)	(57,400)
Accounts payable and accrued liabilities	$ (22,623)	$ (22,623)	23,300
Deferred sales commission			$ 27,300

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