XML 50 R36.htm IDEA: XBRL DOCUMENT v3.22.4
Background, Basis of Presentation and Liquidity (Details Narrative) - USD ($)
$ / shares in Units, $ in Thousands
 3 Months Ended 9 Months Ended 26 Months Ended
Jan. 10, 2022
Dec. 23, 2020
Sep. 18, 2020
Apr. 08, 2019
Jan. 31, 2023
Jan. 31, 2022
Jan. 31, 2023
Jan. 31, 2022
Jan. 31, 2023
Apr. 30, 2022
Nov. 20, 2020
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]                      
Net loss         $ 6,090 $ 5,471 $ 16,786 $ 13,721      
Cash in operations             16,089 15,787      
Accumulated deficit         270,556   270,556   $ 270,556 $ 253,770  
Cash         11,000   11,000   11,000    
Short-term investments         30,005   30,005   30,005 $ 49,384  
Offering amount capacity             $ 90      
Number of common stock shares sold       1,542,000              
2020 ATM Facility [Member]                      
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]                      
Proceeds from issuance or sale of equity, net of issuance costs $ 75,000                    
Offering amount capacity $ 25,000                    
2020 ATM Facility [Member] | Alliance Global Partners [Member]                      
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]                      
Offering amount capacity         $ 50,000   50,000   50,000   $ 100,000
Proceeds from issuance or sale of equity, net of issuance costs                 $ 50,000    
Offering amount capacity             25,000        
Stock Purchase Agreement [Member] | Aspire Capital Fund, LLC [Member]                      
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]                      
Proceeds from issuance or sale of equity, net of issuance costs             $ 11,800        
Aggregate purchase of common stock.     $ 12,500                
Percentage of outstanding common stock   19.99% 19.99%                
Shares can be issued based upon outstanding percentage     3,722,251                
Additional sales of common stock shares sold   9,864,706                  
Number of common stock shares sold             3,722,251        
Combined purchase price per share         $ 3.17   $ 3.17   $ 3.17    
Proceeds from issuance or sale of equity, net of issuance costs             $ 700