Goodwill and Intangible Assets, Net - Intangible Assets (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Apr. 01, 2018
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Assets	$ 579,185	$ 566,330
Impairment		(2,016)
Accumulated Amortization	(404,299)	(383,533)
Net Assets	174,886	180,781
Developed technology
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Assets	339,521	336,402
Impairment		0
Accumulated Amortization	(236,496)	(223,882)
Net Assets	103,025	112,520
Trademarks
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Assets	5,391	5,391
Impairment		0
Accumulated Amortization	(5,391)	(5,391)
Net Assets	0	0
Customer relationships
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Assets	201,997	201,997
Impairment		0
Accumulated Amortization	(155,501)	(149,416)
Net Assets	46,496	52,581
Intellectual property licenses
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Assets	7,500	7,500
Impairment		0
Accumulated Amortization	(4,500)	(3,901)
Net Assets	3,000	3,599
Software licenses
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Assets	20,894	6,023
Impairment		0
Accumulated Amortization	(2,411)	(943)
Net Assets	18,483	5,080
Total amortizable purchased intangible assets
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Assets	575,303	557,313
Impairment		0
Accumulated Amortization	(404,299)	(383,533)
Net Assets	171,004	173,780
In-process research and development (IPR&D)
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Assets	3,882	9,017
Impairment		(2,016)
Accumulated Amortization	0	0
Net Assets	$ 3,882	$ 7,001