Net Loss Per Ordinary Share - Computation of Basic and Diluted Loss Per Ordinary Share (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Apr. 30, 2020	Apr. 30, 2019
Numerator:
Net loss	$ (15,463)	$ (17,311)
Denominator:
Weighted-average ordinary shares - basic	34,080,330	32,492,044
Weighted-average ordinary shares - diluted	34,080,330	32,492,044
Net loss per ordinary share:
Basic	$ (0.45)	$ (0.53)
Diluted	$ (0.45)	$ (0.53)