Stockholders' Equity - Common Stock (Details) - shares shares in Millions	Jan. 31, 2025	Jan. 31, 2024
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options outstanding (in shares)	8	12
Stock available for future grant or issuance (in shares)	73	60
Total shares available for future grant (in shares)	121
2013 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock available for future grant or issuance (in shares)	73
2014 Inducement Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock available for future grant or issuance (in shares)	1
Amended and Restated 2004 Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock available for future grant or issuance (in shares)	13
Restricted stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock awards and units and performance-based stock units outstanding (in shares)	26	28