Shares Used In Computing Diluted Net Income (Loss) Per Share - Shares Used In Computing Diluted Net Loss Per Share (Detail) - shares shares in Thousands	3 Months Ended		9 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2020	Dec. 31, 2019
Earnings Per Share [Abstract]
Weighted average common shares outstanding used in calculating basic net income (loss) per share attributable to Viasat, Inc. common stockholders	67,995	61,813	65,704	61,405
Weighted average options to purchase common stock as determined by application of the treasury stock method		90
Weighted average restricted stock units to acquire common stock as determined by application of the treasury stock method	108	773
Weighted average potentially issuable shares in connection with certain terms of the ViaSat 401(k) Profit Sharing Plan and Employee Stock Purchase Plan	565	240
Weighted average shares used in computing diluted net income (loss) per share attributable to Viasat, Inc. common stockholders	68,668	62,916	65,704	61,405