XML 40 R27.htm IDEA: XBRL DOCUMENT v3.21.2
Basis of Presentation - Valuation Assumptions for Stock Options (Details) - $ / shares
6 Months Ended
Jul. 31, 2021
Aug. 01, 2020
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]    
Expected volatility, minimum 97.40% 82.30%
Expected volatility, maximum 104.90% 87.80%
Risk-free interest rate, minimum 0.31% 0.22%
Risk-free interest rate, maximum 0.60% 0.27%
Weighted average fair value of options granted $ 0.47 $ 0.32
Minimum    
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]    
Expected life 3 years 3 years
Maximum    
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]    
Expected life 4 years 4 years