Debt - Additional Information (Detail)					1 Months Ended	3 Months Ended		9 Months Ended		12 Months Ended
	Dec. 15, 2022	Dec. 22, 2021 USD ($) shares	Dec. 21, 2021	Dec. 10, 2021 USD ($)	Aug. 31, 2017 USD ($) d $ / shares	Mar. 31, 2022 USD ($) d	Mar. 31, 2021 USD ($)	Mar. 31, 2022 USD ($)	Mar. 31, 2021 USD ($)	Jun. 30, 2021 USD ($)	Dec. 15, 2021 USD ($)	Dec. 02, 2021 USD ($)	Nov. 01, 2021	Jul. 01, 2021 USD ($)
Line of Credit Facility [Line Items]
Debt issuance costs capitalized						$ 17,000,000		$ 17,000,000
Amortization of debt issuance costs						2,000,000		3,000,000
Cash, cash equivalents, and restricted cash						2,600,315,000		2,600,315,000		$ 1,591,892,000
Current portion of long-term debt						1,383,959,000		1,383,959,000		62,050,000
Retained earnings						(1,321,779,000)		(1,321,779,000)		(1,136,777,000)
Available credit under lines of credit						$ 450,000,000		$ 450,000,000
5.000% Senior Notes
Line of Credit Facility [Line Items]
Debt instrument, interest rate				5.00%		5.00%		5.00%
Aggregate principal amount of senior notes				$ 990,000,000
5.000% Senior Notes | Senior Notes, Redemption, Period One
Line of Credit Facility [Line Items]
Redemption price percentage				100.00%
5.000% Senior Notes | Senior Notes, Redemption, Period Two
Line of Credit Facility [Line Items]
Redemption price percentage				40.00%
5.000% Senior Notes | Senior Notes, Redemption, Period Three
Line of Credit Facility [Line Items]
Redemption price percentage				105.00%
Senior Notes
Line of Credit Facility [Line Items]
Cash, cash equivalents, and restricted cash						$ 990,000,000		$ 990,000,000
Senior Notes | Subsequent Event
Line of Credit Facility [Line Items]
Redemption price percentage	100.00%
0.50% Finisar Convertible Notes
Line of Credit Facility [Line Items]
Debt instrument, interest rate						0.50%		0.50%					0.50%
Redemption price percentage			100.00%
Debt instrument, repurchase amount											$ 14,600,000
Debt conversion, shares issued (in shares) | shares		45
Payment to settle conversion of debt and redeem notes		$ 300,000
Amended and Restated Commitment Letter
Line of Credit Facility [Line Items]
Aggregate principal amount												$ 4,000,000,000
0.25% Convertible Senior Notes due 2022
Line of Credit Facility [Line Items]
Debt instrument, interest rate						0.25%	0.25%	0.25%	0.25%
Aggregate principal amount of senior notes					$ 345,000,000
Interest expense						$ 216,000	$ 216,000	$ 656,000	$ 656,000
Debt instrument, conversion ratio					0.02125
Debt instrument conversion, conversion price per share (in usd per share) | $ / shares					$ 47.06
Debt instrument conversion, If-converted value of notes								$ 531,000,000		$ 532,000,000
Debt instrument conversion, trading days | d					20	20
Debt instrument conversion, consecutive trading days | d					30	30
Debt instrument conversion, conversion price percentage					130.00%	130.00%
Debt instrument conversion, business day period					5 days
Debt instrument conversion, measurement period					5 days
Debt instrument conversion, measurement period percentage					98.00%
Effective interest rate						1.00%	5.00%	1.00%	5.00%
0.25% Convertible Senior Notes due 2022 | Cumulative Effect, Period of Adoption, Adjustment
Line of Credit Facility [Line Items]
Current portion of long-term debt														$ (15,000,000)
Deferred tax liabilities														3,000,000
Retained earnings														$ 11,000,000
Bank of America, N.A.
Line of Credit Facility [Line Items]
Letter of credit sub-facility maximum borrowing capacity						$ 25,000,000		$ 25,000,000
Swing loan sub-facility maximum initial borrowing capacity						20,000,000		20,000,000
Senior Secured Credit Facility | Bank of America, N.A.
Line of Credit Facility [Line Items]
Aggregate principal amount						2,425,000,000		$ 2,425,000,000
Credit facilities, outstanding amounts become due and payable, prior to maturity of Senior notes, period								120 days
Term A Loan Facility | LIBOR
Line of Credit Facility [Line Items]
Debt instrument, rate added on variable rate								1.375%
Term A Loan Facility | Bank of America, N.A.
Line of Credit Facility [Line Items]
Aggregate principal amount						1,255,000,000		$ 1,255,000,000
Debt agreement term								5 years
Redemption price percentage								1.25%
Term B Loan Facility | Bank of America, N.A.
Line of Credit Facility [Line Items]
Aggregate principal amount						720,000,000		$ 720,000,000
Debt agreement term								7 years
Revolving Credit Facility
Line of Credit Facility [Line Items]
Aggregate principal amount				$ 350,000,000
Revolving Credit Facility | LIBOR
Line of Credit Facility [Line Items]
Debt instrument, rate added on variable rate				2.00%
Revolving Credit Facility | Term A Facility and Revolving Credit Facility | LIBOR
Line of Credit Facility [Line Items]
Debt instrument, rate added on variable rate				0.00%
Revolving Credit Facility | Term A Facility and Revolving Credit Facility | LIBOR | Minimum
Line of Credit Facility [Line Items]
Debt instrument, rate added on variable rate				1.75%
Revolving Credit Facility | Term A Facility and Revolving Credit Facility | LIBOR | Maximum
Line of Credit Facility [Line Items]
Debt instrument, rate added on variable rate				2.50%
Revolving Credit Facility | Bank of America, N.A.
Line of Credit Facility [Line Items]
Aggregate principal amount						450,000,000		$ 450,000,000
Debt agreement term								5 years
Senior Credit Facilities | Fifth Fiscal Quarter Through Eighth Fiscal Quarter After Closing Date
Line of Credit Facility [Line Items]
Leverage ratio								4.50
Senior Credit Facilities | Subsequent Fiscal Quarter
Line of Credit Facility [Line Items]
Leverage ratio								4.00
Senior Credit Facilities | Minimum
Line of Credit Facility [Line Items]
Interest coverage ratio								3.00
Senior Credit Facilities | Maximum | First Four Fiscal Quarters After Closing Date
Line of Credit Facility [Line Items]
Leverage ratio								5.00
Senior Credit Facilities | Federal Funds Rate
Line of Credit Facility [Line Items]
Debt instrument, rate added on variable rate								0.50%
Senior Credit Facilities | Eurodollar
Line of Credit Facility [Line Items]
Debt instrument, rate added on variable rate								1.00%
New Term Loan A Credit Facility
Line of Credit Facility [Line Items]
Aggregate principal amount				$ 850,000,000
New Term Loan A Credit Facility | LIBOR
Line of Credit Facility [Line Items]
Debt instrument, rate added on variable rate				2.00%
New Term Loan A Credit Facility | Term A Facility and Revolving Credit Facility | LIBOR
Line of Credit Facility [Line Items]
Debt instrument, rate added on variable rate				0.00%
New Term Loan A Credit Facility | Term A Facility and Revolving Credit Facility | LIBOR | Minimum
Line of Credit Facility [Line Items]
Debt instrument, rate added on variable rate				1.75%
New Term Loan A Credit Facility | Term A Facility and Revolving Credit Facility | LIBOR | Maximum
Line of Credit Facility [Line Items]
Debt instrument, rate added on variable rate				2.50%
New Term Loan B Credit Facility | LIBOR
Line of Credit Facility [Line Items]
Debt instrument, rate added on variable rate				2.75%
New Term Loan B Credit Facility | New Term Loan B Credit Facility
Line of Credit Facility [Line Items]
Interest expense						14,000,000
New Term Loan B Credit Facility | New Term Loan B Credit Facility | LIBOR
Line of Credit Facility [Line Items]
Debt instrument, rate added on variable rate				0.50%
New Term Facilities
Line of Credit Facility [Line Items]
Aggregate principal amount				$ 2,800,000,000
Bridge Loan
Line of Credit Facility [Line Items]
Aggregate principal amount of senior notes				$ 990,000,000
Interest expense						$ 3,000,000