Document and Entity Information - shares	6 Months Ended
	Sep. 30, 2020	Oct. 23, 2020
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2020
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q2
Trading Symbol	VSAT
Title of 12(b) Security	Common Stock, par value $0.0001 per share
Security Exchange Name	NASDAQ
Entity Registrant Name	VIASAT, INC.
Entity Central Index Key	0000797721
Current Fiscal Year End Date	--03-31
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Common Stock, Shares Outstanding		67,532,889
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Shell Company	false
Document Quarterly Report	true
Document Transition Report	false
Entity File Number	000-21767
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	33-0174996
Entity Address, Address Line One	6155 El Camino Real
Entity Address, City or Town	Carlsbad
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	92009
City Area Code	760
Local Phone Number	476-2200