Basis of Presentation - Summary of Impact of Adopting New Standards on Condensed Consolidated Statements of Operations and Comprehensive Income (Loss) (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Disaggregation Of Revenue [Line Items]
Total revenues	$ 517,474	$ 393,074	$ 956,343	$ 773,118
Selling, general and administrative	113,120	90,084	225,762	179,257
Independent research and development	31,360	46,268	64,733	91,333
Loss from operations	(21,571)	(15,860)	(76,050)	(33,810)
Interest expense	(14,074)	(197)	(25,398)	(253)
Loss before income taxes	(35,616)	(26,097)	(101,383)	(44,010)
Benefit from income taxes	9,704	11,464	38,909	20,644
Net loss	(25,598)	(13,892)	(61,095)	(23,138)
Net loss attributable to Viasat, Inc.	$ (25,724)	$ (13,689)	$ (59,734)	$ (22,728)
Basic net loss per share attributable to Viasat, Inc. common stockholders	$ (0.43)	$ (0.24)	$ (1.00)	$ (0.39)
Diluted net loss per share attributable to Viasat, Inc. common stockholders	$ (0.43)	$ (0.24)	$ (1.00)	$ (0.39)
Product [Member]
Disaggregation Of Revenue [Line Items]
Total revenues	$ 280,435	$ 181,783	$ 498,564	$ 347,901
Cost of revenues	216,900	133,850	390,348	256,495
Service [Member]
Disaggregation Of Revenue [Line Items]
Total revenues	237,039	211,291	457,779	425,217
Cost of revenues	175,230	$ 135,412	346,662	$ 273,263
Impact of ASC 606 [Member] | ASC 606 [Member]
Disaggregation Of Revenue [Line Items]
Total revenues	(5,290)		(5,777)
Selling, general and administrative	3,871		6,210
Independent research and development	1,500		4,245
Loss from operations	(7,317)		(13,015)
Interest expense	1,011		2,003
Loss before income taxes	(6,306)		(11,012)
Benefit from income taxes	1,940		1,755
Net loss	(4,366)		(9,257)
Net loss attributable to Viasat, Inc.	$ (4,366)		$ (9,257)
Basic net loss per share attributable to Viasat, Inc. common stockholders	$ (0.07)		$ (0.16)
Diluted net loss per share attributable to Viasat, Inc. common stockholders	$ (0.07)		$ (0.16)
Impact of ASC 606 [Member] | ASC 606 [Member] | Product [Member]
Disaggregation Of Revenue [Line Items]
Total revenues	$ (4,779)		$ (4,200)
Cost of revenues	(3,396)		(3,147)
Impact of ASC 606 [Member] | ASC 606 [Member] | Service [Member]
Disaggregation Of Revenue [Line Items]
Total revenues	(511)		(1,577)
Cost of revenues	52		(70)
Historical Accounting Method [Member] | ASC 606 [Member]
Disaggregation Of Revenue [Line Items]
Total revenues	512,184		950,566
Selling, general and administrative	116,991		231,972
Independent research and development	32,860		68,978
Loss from operations	(28,888)		(89,065)
Interest expense	(13,063)		(23,395)
Loss before income taxes	(41,922)		(112,395)
Benefit from income taxes	11,644		40,664
Net loss	(29,964)		(70,352)
Net loss attributable to Viasat, Inc.	$ (30,090)		$ (68,991)
Basic net loss per share attributable to Viasat, Inc. common stockholders	$ (0.50)		$ (1.16)
Diluted net loss per share attributable to Viasat, Inc. common stockholders	$ (0.50)		$ (1.16)
Historical Accounting Method [Member] | ASC 606 [Member] | Product [Member]
Disaggregation Of Revenue [Line Items]
Total revenues	$ 275,656		$ 494,364
Cost of revenues	213,504		387,201
Historical Accounting Method [Member] | ASC 606 [Member] | Service [Member]
Disaggregation Of Revenue [Line Items]
Total revenues	236,528		456,202
Cost of revenues	$ 175,282		$ 346,592