Consolidated Statements of Operations - USD ($) $ in Thousands	12 Months Ended
	Jan. 31, 2021	Jan. 31, 2020	Jan. 31, 2019
Income Statement [Abstract]
Revenue	$ 222,990	$ 228,732	$ 227,768
Cost of revenue	87,417	96,023	89,624
Gross profit	135,573	132,709	138,144
Operating expenses:
Research and development	140,759	129,724	128,084
Selling, general and administrative	55,980	52,634	50,480
Total operating expenses	196,739	182,358	178,564
Loss from operations	(61,166)	(49,649)	(40,420)
Other income, net	3,863	8,021	5,868
Loss before income taxes	(57,303)	(41,628)	(34,552)
Provision (benefit) for income taxes	2,483	3,164	(4,105)
Net loss	$ (59,786)	$ (44,792)	$ (30,447)
Net loss per share attributable to ordinary shareholders:
Basic	$ (1.72)	$ (1.35)	$ (0.93)
Diluted	$ (1.72)	$ (1.35)	$ (0.93)
Weighted-average shares used to compute net loss per share attributable to ordinary shareholders:
Basic	34,679,717	33,083,562	32,713,606
Diluted	34,679,717	33,083,562	32,713,606