The Company and a Summary of Its Significant Accounting Policies - Summary of Impact of Adopting New Standards on Consolidated Statements of Operations and Comprehensive Income (Loss) (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Disaggregation Of Revenue [Line Items]
Total revenues	$ 2,068,258	$ 1,594,625	$ 1,559,337
Selling, general and administrative	458,458	385,420	333,468
Independent research and development	123,044	168,347	129,647
Income (loss) from operations	(60,620)	(92,187)	36,459
Interest expense	(50,010)	(4,026)	(12,083)
Loss before income taxes	(110,481)	(105,470)	25,384
Benefit from income taxes	41,014	35,217	(3,617)
Net (loss) income	(66,469)	(68,275)	21,767
Net loss attributable to Viasat, Inc.	$ (67,623)	$ (67,305)	$ 23,767
Basic net loss per share attributable to Viasat, Inc. common stockholders	$ (1.13)	$ (1.15)	$ 0.45
Diluted net loss per share attributable to Viasat, Inc. common stockholders	$ (1.13)	$ (1.15)	$ 0.45
Product [Member]
Disaggregation Of Revenue [Line Items]
Total revenues	$ 1,092,691	$ 755,547	$ 713,936
Cost of revenues	834,472	553,677	524,026
Service [Member]
Disaggregation Of Revenue [Line Items]
Total revenues	975,567	839,078	845,401
Cost of revenues	703,249	$ 567,137	$ 524,949
Impact of ASC 606 [Member] | ASC 606 [Member]
Disaggregation Of Revenue [Line Items]
Total revenues	(8,325)
Selling, general and administrative	9,278
Independent research and development	7,498
Income (loss) from operations	(20,961)
Interest expense	4,206
Loss before income taxes	(16,754)
Benefit from income taxes	4,499
Net (loss) income	(12,256)
Net loss attributable to Viasat, Inc.	$ (12,256)
Basic net loss per share attributable to Viasat, Inc. common stockholders	$ (0.20)
Diluted net loss per share attributable to Viasat, Inc. common stockholders	$ (0.20)
Impact of ASC 606 [Member] | ASC 606 [Member] | Product [Member]
Disaggregation Of Revenue [Line Items]
Total revenues	$ (5,263)
Cost of revenues	(3,877)
Impact of ASC 606 [Member] | ASC 606 [Member] | Service [Member]
Disaggregation Of Revenue [Line Items]
Total revenues	(3,062)
Cost of revenues	(263)
Historical Accounting Method [Member] | ASC 606 [Member]
Disaggregation Of Revenue [Line Items]
Total revenues	2,059,933
Selling, general and administrative	467,736
Independent research and development	130,542
Income (loss) from operations	(81,581)
Interest expense	(45,804)
Loss before income taxes	(127,235)
Benefit from income taxes	45,513
Net (loss) income	(78,725)
Net loss attributable to Viasat, Inc.	$ (79,879)
Basic net loss per share attributable to Viasat, Inc. common stockholders	$ (1.33)
Diluted net loss per share attributable to Viasat, Inc. common stockholders	$ (1.33)
Historical Accounting Method [Member] | ASC 606 [Member] | Product [Member]
Disaggregation Of Revenue [Line Items]
Total revenues	$ 1,087,428
Cost of revenues	830,595
Historical Accounting Method [Member] | ASC 606 [Member] | Service [Member]
Disaggregation Of Revenue [Line Items]
Total revenues	972,505
Cost of revenues	$ 702,986