Shares Used In Computing Diluted Net (Loss) Income Per Share - Additional Information (Detail) - shares	3 Months Ended		9 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2017	Dec. 31, 2016
Employee Stock Options [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive shares	1,355,232	648,043	1,376,667	478,400
Total Shareholder Return Performance Stock Option [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive shares	270,256		90,413
Restricted Stock Units [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive shares	1,208,047	500	811,747	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	183,537		163,440