Income Taxes (Details 2) - USD ($) $ in Thousands	3 Months Ended				12 Months Ended
	Mar. 31, 2018	Dec. 30, 2017	Apr. 01, 2017	Dec. 31, 2016	Mar. 31, 2018	Apr. 01, 2017	Apr. 02, 2016
ReconciliationOfProvisionOfIncomeTaxes [Line Items]
Document Fiscal Year Focus					2018
Income tax expense at statutory federal rate					$ (5,407)	$ (9,557)	$ 1,002
Income tax expense at statutory federal rate, Percentage					31.54%	35.00%	35.00%
Decrease (increase) resulting from:
State benefit (provision), net of federal (provision) benefit					$ 474	$ (662)	$ (1,320)
State benefit (provision), net of federal (provision) benefit, Percentage					(2.77%)	2.42%	(46.14%)
Research and development credits					$ 38,054	$ 15,352	$ 15,459
Research and development credits, Percentage					(221.95%)	(56.22%)	540.21%
Effect of changes in income tax rate applied to net deferred tax assets					$ 39,168	$ 1,163	$ (2,716)
Effect of changes in income tax rate applied to net deferred tax assets, Percentage					(228.45%)	(4.26%)	(94.92%)
Foreign tax rate difference					$ 21,829	$ (11,298)	$ 4,114
Foreign tax rate difference, Percentage					(127.32%)	41.38%	143.77%
Foreign permanent differences, amount					$ (2,598)	$ (8,432)	$ (1,700)
Foreign permanent differences, percent					15.15%	30.88%	(59.40%)
Change in valuation allowance					$ (1,632)	$ 1,363	$ (25,120)
Change in valuation allowance, Percentage					9.52%	(4.99%)	(877.84%)
Stock-based compensation					$ 9,924	$ (3,228)	$ (5,362)
Share-based compensation, Percentage					(57.88%)	11.82%	(187.37%)
Tax reserve adjustments					$ (29,188)	$ (21,789)	$ (8,699)
Tax reserve adjustments, Percentage					170.24%	79.80%	(303.99%)
Deemed dividend					$ (5,098)	$ (6,989)	$ (3,984)
Deemed Dividend, Percentage					29.73%	25.60%	(139.21%)
U.S. Tax Toll Charge					$ (116,419)	$ 0	$ 0
U.S. Tax Toll Charge, Percent					679.03%	0.00%	0.00%
Intra-entity transfer					$ (6,873)	$ 0	$ 0
Intra-entity transfer, percent					40.09%	0.00%	0.00%
Other income tax benefit (expense)					$ 333	$ 214	$ 2,343
Other income tax benefit (expense), Percentage					(1.94%)	(0.79%)	81.89%
Total	$ 31,200	$ (98,500)	$ 93,200	$ (123,200)	$ (57,433)	$ (43,863)	$ (25,983)
Total, Percentage					334.99%	160.64%	(908.00%)