Condensed Consolidated Statements of Comprehensive Loss (Unaudited) - USD ($) $ in Thousands |
3 Months Ended | |
|---|---|---|
Apr. 30, 2019 |
Apr. 30, 2018 |
|
| Statement Of Income And Comprehensive Income [Abstract] | ||
| Net loss | $ (17,311) | $ (10,006) |
| Other comprehensive income (loss), net of tax: | ||
| Unrealized gains (losses) on investments | 254 | (110) |
| Other comprehensive income (loss), net of tax | 254 | (110) |
| Comprehensive loss | $ (17,057) | $ (10,116) |