Shares Used In Computing Diluted Net (Loss) Income Per Share - Shares Used In Computing Diluted Net Income Per Share (Detail) - shares shares in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Earnings Per Share [Abstract]
Weighted average common shares outstanding used in calculating basic net (loss) income per share attributable to ViaSat, Inc. common stockholders	58,229	49,503	58,039	49,319
Weighted average options to purchase common stock as determined by application of the treasury stock method		276		281
Weighted average restricted stock units to acquire common stock as determined by application of the treasury stock method		669		637
Weighted average potentially issuable shares in connection with certain terms of the ViaSat 401(k) Profit Sharing Plan and Employee Stock Purchase Plan		85		156
Weighted average shares used in computing diluted net (loss) income per share attributable to ViaSat, Inc. common stockholders	58,229	50,533	58,039	50,393