Segment Reporting - Company's Revenue by Geographic Region Based on Bill-to Location (Detail) - USD ($) $ in Thousands |
3 Months Ended | |
|---|---|---|
Apr. 30, 2019 |
Apr. 30, 2018 |
|
| Revenue from External Customer [Line Items] | ||
| Total revenue | $ 47,188 | $ 56,938 |
| Taiwan [Member] | ||
| Revenue from External Customer [Line Items] | ||
| Total revenue | 27,600 | 33,206 |
| Asia Pacific [Member] | ||
| Revenue from External Customer [Line Items] | ||
| Total revenue | 14,488 | 16,356 |
| Europe [Member] | ||
| Revenue from External Customer [Line Items] | ||
| Total revenue | 3,483 | 4,582 |
| North America other than United States [Member] | ||
| Revenue from External Customer [Line Items] | ||
| Total revenue | 883 | 2,006 |
| United States [Member] | ||
| Revenue from External Customer [Line Items] | ||
| Total revenue | $ 734 | $ 788 |