Shares Used In Computing Diluted Net Income (Loss) Per Share - Shares Used In Computing Diluted Net Loss Per Share (Detail) - shares shares in Thousands	12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Mar. 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	66,444	61,632	59,942
Weighted average restricted stock units to acquire common stock as determined by application of the treasury stock method	170
Weighted average potentially issuable shares in connection with certain terms of the Viasat 401(k) Profit Sharing Plan and Employee Stock Purchase Plan	406
Weighted average shares used in computing diluted net income (loss) per share attributable to Viasat, Inc. common stockholders	67,020	61,632	59,942