Segment Reporting - Company's Revenue by Geographic Region Based on Bill-to Location (Detail) - USD ($) $ in Thousands	12 Months Ended
	Jan. 31, 2021	Jan. 31, 2020	Jan. 31, 2019
Revenue from External Customer [Line Items]
Total revenue	$ 222,990	$ 228,732	$ 227,768
Taiwan [Member]
Revenue from External Customer [Line Items]
Total revenue	139,327	137,946	132,199
Asia Pacific [Member]
Revenue from External Customer [Line Items]
Total revenue	57,270	66,867	66,981
Europe [Member]
Revenue from External Customer [Line Items]
Total revenue	9,415	11,134	18,244
North America other than United States [Member]
Revenue from External Customer [Line Items]
Total revenue	10,304	8,402	7,028
United States [Member]
Revenue from External Customer [Line Items]
Total revenue	$ 6,674	$ 4,383	$ 3,316