Segment Reporting - Company's Revenue by Geographic Region Based on Bill-to Location (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Oct. 31, 2021	Oct. 31, 2020	Oct. 31, 2021	Oct. 31, 2020
Revenue from External Customer [Line Items]
Total revenue	$ 92,167	$ 56,090	$ 241,627	$ 160,848
Taiwan [Member]
Revenue from External Customer [Line Items]
Total revenue	59,412	35,073	153,135	96,846
Asia Pacific [Member]
Revenue from External Customer [Line Items]
Total revenue	21,323	14,642	60,122	43,635
Europe [Member]
Revenue from External Customer [Line Items]
Total revenue	4,432	1,970	11,837	6,856
North America other than United States [Member]
Revenue from External Customer [Line Items]
Total revenue	5,984	2,433	13,117	8,449
United States [Member]
Revenue from External Customer [Line Items]
Total revenue	$ 1,016	$ 1,972	$ 3,416	$ 5,062