Shares Used In Computing Diluted Net (Loss) Income Per Share - Additional Information (Detail) - shares	3 Months Ended		6 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Employee Stock Options [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive shares	1,400,231	413,750	1,381,582	398,771
Restricted Stock Units [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive shares	598,245	0	545,821	0
ViaSat 401(k) Profit Sharing Plan and Employee Stock Purchase Plan [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive shares	114,770		159,524