Net Loss Per Ordinary Share - Computation of Basic and Diluted Net Loss Per Ordinary Share (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Jan. 31, 2021	Jan. 31, 2020	Jan. 31, 2019
Numerator:
Net loss	$ (59,786)	$ (44,792)	$ (30,447)
Denominator:
Weighted-average ordinary shares - basic	34,679,717	33,083,562	32,713,606
Weighted-average ordinary shares - diluted	34,679,717	33,083,562	32,713,606
Net loss per ordinary share:
Basic	$ (1.72)	$ (1.35)	$ (0.93)
Diluted	$ (1.72)	$ (1.35)	$ (0.93)