Net Loss Per Share - Antidilutive Securities Excluded from Computation of Diluted Net Loss per Common Share of Common Stock Equivalents (Detail) - shares shares in Thousands	3 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of diluted net loss per common share (in shares)	7,853	5,312
ESPP shares
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of diluted net loss per common share (in shares)	117	77
RSUs
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of diluted net loss per common share (in shares)	4,482	2,374
Options to purchase common stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of diluted net loss per common share (in shares)	3,254	2,861