Condensed Consolidated Statements of Operations (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 31, 2020	Jul. 31, 2019	Jul. 31, 2020	Jul. 31, 2019
Income Statement [Abstract]
Revenue	$ 50,113	$ 56,410	$ 104,758	$ 103,598
Cost of revenue	19,155	23,973	41,780	43,308
Gross profit	30,958	32,437	62,978	60,290
Operating expenses:
Research and development	32,802	30,420	67,002	63,437
Selling, general and administrative	13,445	12,425	26,880	25,502
Total operating expenses	46,247	42,845	93,882	88,939
Loss from operations	(15,289)	(10,408)	(30,904)	(28,649)
Other income, net	1,280	2,195	2,558	4,391
Loss before income taxes	(14,009)	(8,213)	(28,346)	(24,258)
Provision for income taxes	747	1,978	1,873	3,244
Net loss	$ (14,756)	$ (10,191)	$ (30,219)	$ (27,502)
Net loss per share attributable to ordinary shareholders:
Basic	$ (0.43)	$ (0.31)	$ (0.88)	$ (0.84)
Diluted	$ (0.43)	$ (0.31)	$ (0.88)	$ (0.84)
Weighted-average shares used to compute net loss per share attributable to ordinary shareholders:
Basic	34,480,307	32,860,974	34,280,318	32,676,509
Diluted	34,480,307	32,860,974	34,280,318	32,676,509