Condensed Consolidated Statements of Operations (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Oct. 31, 2020	Oct. 31, 2019	Oct. 31, 2020	Oct. 31, 2019
Income Statement [Abstract]
Revenue	$ 56,090	$ 67,922	$ 160,848	$ 171,520
Cost of revenue	21,298	28,819	63,078	72,127
Gross profit	34,792	39,103	97,770	99,393
Operating expenses:
Research and development	36,573	32,480	103,575	95,917
Selling, general and administrative	14,468	13,791	41,348	39,293
Total operating expenses	51,041	46,271	144,923	135,210
Loss from operations	(16,249)	(7,168)	(47,153)	(35,817)
Other income, net	673	1,917	3,231	6,308
Loss before income taxes	(15,576)	(5,251)	(43,922)	(29,509)
Provision (benefit) for income taxes	1,502	(942)	3,375	2,302
Net loss	$ (17,078)	$ (4,309)	$ (47,297)	$ (31,811)
Net loss per share attributable to ordinary shareholders:
Basic	$ (0.49)	$ (0.13)	$ (1.37)	$ (0.97)
Diluted	$ (0.49)	$ (0.13)	$ (1.37)	$ (0.97)
Weighted-average shares used to compute net loss per share attributable to ordinary shareholders:
Basic	34,819,880	33,304,171	34,460,172	32,885,729
Diluted	34,819,880	33,304,171	34,460,172	32,885,729