Composition of Certain Balance Sheet Captions - Composition of Certain Balance Sheet Captions (Detail) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Sep. 30, 2021	Mar. 31, 2021
Accounts receivable, net:
Accounts receivable, Billed	$ 272,689	$ 172,559
Accounts receivable, Unbilled	102,111	70,785
Allowance for doubtful accounts	(5,578)	(4,692)
Accounts receivable, net	369,222	238,652
Inventories:
Raw materials	86,810	98,338
Work in process	75,657	71,875
Finished goods	185,875	166,459
Inventories	348,342	336,672
Prepaid expenses and other current assets:
Prepaid expenses	96,144	94,405
Other	35,025	25,555
Prepaid expenses and other current assets	131,169	119,960
Property, equipment and satellites, net:
Property, equipment and satellites, gross	5,352,832	4,834,919
Less: accumulated depreciation and amortization	(1,887,465)	(1,784,436)
Property and equipment, net	3,465,367	3,050,483
Other acquired intangible assets, net:
Other acquired intangible assets, gross	379,312	151,549
Less: accumulated amortization	(135,981)	(141,981)
Other acquired intangible assets, net	243,331	9,568
Other assets:
Investment in unconsolidated affiliate		176,938
Deferred income taxes	290,463	273,288
Capitalized software costs, net	228,910	237,100
Patents, orbital slots and other licenses, net	59,338	52,889
Other	107,774	95,212
Other assets	686,485	835,427
Accrued and other liabilities:
Collections in excess of revenues and deferred revenues	201,050	216,594
Accrued employee compensation	68,042	87,153
Accrued vacation	54,606	59,509
Warranty reserve, current portion	5,234	6,693
Operating lease liabilities	51,683	48,896
Other	$ 130,478	$ 113,986
Operating Lease Liability Current Statement Of Financial Position Extensible List	http://www.viasat.com/#AccruedAndOtherLiabilitiesCurrent	http://www.viasat.com/#AccruedAndOtherLiabilitiesCurrent
Accrued and other liabilities	$ 511,093	$ 532,831
Other liabilities:
Deferred revenues, long-term portion	86,569	84,654
Warranty reserve, long-term portion	6,036	5,193
Satellite performance incentive obligations, long-term portion	20,471	22,191
Deferred income taxes, long-term	15,651
Other	35,220	25,312
Other liabilities	163,947	137,350
Technology [Member]
Other acquired intangible assets, net:
Other acquired intangible assets, gross	151,739	78,185
Contracts and Customer Relationships [Member]
Other acquired intangible assets, net:
Other acquired intangible assets, gross	168,204	55,161
Satellite Co-Location Rights [Member]
Other acquired intangible assets, net:
Other acquired intangible assets, gross	8,600	8,600
Trade Name [Member]
Other acquired intangible assets, net:
Other acquired intangible assets, gross	32,128	5,940
Other [Member]
Other acquired intangible assets, net:
Other acquired intangible assets, gross	18,641	3,663
Satellites [Member]
Property, equipment and satellites, net:
Property, equipment and satellites, gross	1,063,748	969,952
Satellites under Construction [Member]
Property, equipment and satellites, net:
Property, equipment and satellites, gross	1,570,169	1,338,408
Equipment and Software [Member]
Property, equipment and satellites, net:
Property, equipment and satellites, gross	1,634,630	1,505,697
CPE Leased Equipment [Member]
Property, equipment and satellites, net:
Property, equipment and satellites, gross	405,349	409,942
Satellite Ka-band Capacity Obtained under Finance Leases [Member]
Property, equipment and satellites, net:
Property, equipment and satellites, gross	173,480	173,467
Furniture and Fixtures [Member]
Property, equipment and satellites, net:
Property, equipment and satellites, gross	58,497	57,433
Leasehold Improvements [Member]
Property, equipment and satellites, net:
Property, equipment and satellites, gross	152,806	149,324
Buildings [Member]
Property, equipment and satellites, net:
Property, equipment and satellites, gross	12,385	8,923
Land [Member]
Property, equipment and satellites, net:
Property, equipment and satellites, gross	3,973	2,291
Construction in Progress [Member]
Property, equipment and satellites, net:
Property, equipment and satellites, gross	$ 277,795	$ 219,482