Annual report pursuant to Section 13 and 15(d)

Consolidated Statements of Stockholders' (Deficit) Equity

v3.22.2.2
Consolidated Statements of Stockholders' (Deficit) Equity - USD ($)
shares in Thousands, $ in Thousands
Preferred Stock
Common Stock
Registered Direct Offering [Member]
Common Stock
Public Warrant Tender Offering [Member]
Common Stock
Private Warrant Exchange [Member]
Common Stock
Private Equity Offering
Common Stock
Treasury Stock
Public Warrant Tender Offering [Member]
Treasury Stock
Additional Paid-in Capital
Registered Direct Offering [Member]
Additional Paid-in Capital
Public Warrant Tender Offering [Member]
Additional Paid-in Capital
Private Warrant Exchange [Member]
Additional Paid-in Capital
Private Equity Offering
Additional Paid-in Capital
Accumulated Deficit
Registered Direct Offering [Member]
Public Warrant Tender Offering [Member]
Private Warrant Exchange [Member]
Private Equity Offering
Total
Beginning balance at May. 31, 2019           $ 330             $ 225,177 $ (234,420)         $ (8,913)
Beginning balance, shares at May. 31, 2019 95         329,555   159                      
Issuance of stock for convertible note repayment, value           $ 23             10,799           10,822
Issuance of stock for convertible note repayment, shares           22,967                          
Note conversion and extension fees, value           $ 8             3,891           3,899
Note conversion and extension fees, shares           8,232                          
Stock issued via offering, tender or placement, value   $ 39 $ 45 $ 20         $ 12,627 $ 11,855 $ 6,001   13,409   $ 12,666 $ 11,900 $ 6,021   13,409
Stock issued via offering, tender or placement, shares 14 38,856 45,376 20,529                              
Warrant exercises, value           $ 42             20,458           20,500
Warrant exercises, shares           42,024                          
Relative fair market value associated with warrants exercised                         11,949           11,949
Inducement interest expense                   2,713           2,713      
Inducement interest expense related to private warrant exchange, value                         20,724           20,724
Dividends accrued and paid on preferred stock, value                           (945)         (945)
Legal fees in connection with equity offerings                         (16)           (16)
Stock issued for services, value           $ 3             (3)            
Stock issued for services, shares           2,620                          
Stock issued for bonuses and tendered for income tax, value                         154           154
Stock issued for bonuses and tendered for income tax, shares           380   127                      
Stock option exercises, value           $ 9             5,594           5,603
Stock option exercises, shares           8,723                          
Stock-based compensation                         6,548           6,548
Issuance of legal settlement, warrants, value                         22,500           22,500
Offering costs, stock and warrants                 $ (378) (1,059) (197)   (437)   $ (378) (1,059) $ (197)   (437)
Exercise of option to repurchase common stock, value                         (8)           (8)
Net loss                           (139,936)         (139,936)
Ending balance at May. 31, 2020           $ 519             372,301 (375,301)         (2,481)
Ending balance, shares at May. 31, 2020 109         519,262   286                      
Issuance of stock for convertible note repayment, value           $ 24             96,914           96,938
Issuance of stock for convertible note repayment, shares           24,154                          
Stock issued via offering, tender or placement, value         $ 1         $ 828   $ 999       $ 828   $ 1,000  
Stock issued via offering, tender or placement, shares     323   667   157                   35,800 8,900  
Warrant exercises, value       $ 37   $ 38         17,519   18,611       $ 17,556   $ 18,649
Warrant exercises, shares       37,054   37,941                         26,700
Inducement interest expense related to private warrant exchange, value                         13,922           $ 13,922
Dividends accrued and paid on preferred stock, value                           (1,909)         (1,909)
Stock option exercises, value           $ 3             1,835           1,838
Stock option exercises, shares           2,591                          
Stock-based compensation                         9,601           $ 9,601
Issuance of legal settlement, warrants, value           $ 4             (4)            
Issuance of legal settlement, warrants, shares           4,000                          
Conversion of preferred stock to common stock, shares (13)         131                          
Offering costs, stock and warrants                     (495)           (495)    
Issuance of common stock upon vesting of stock based compensation awards, shares                                     200
Net loss                           (176,465)         $ (176,465)
Ending balance at May. 31, 2021           $ 626             532,031 (553,675)         (21,018)
Ending balance, shares at May. 31, 2021 96         626,123   443                      
Issuance of stock for convertible note repayment, value           $ 37             68,344           $ 68,381
Issuance of stock for convertible note repayment, shares           37,110                          
Stock issued via offering, tender or placement, value         $ 38             $ 46,473           $ 46,511  
Stock issued via offering, tender or placement, shares         38,035                           7,900
Warrant exercises, value       $ 8   $ 2         $ 5,382   1,034       $ 5,390   $ 1,036
Warrant exercises, shares       7,920   1,642                         1,400
Inducement interest expense related to private warrant exchange, value           $ 2             6,689           $ 6,691
Inducement interest expense related to private warrant exchange, shares           2,293                          
Dividends accrued and paid on preferred stock, value           $ 1             305 (1,636)         (1,330)
Dividends accrued and paid on preferred stock, shares           613                          
Stock issued for bonuses and tendered for income tax, value           $ 2             666           668
Stock issued for bonuses and tendered for income tax, shares           2,582                          
Stock option exercises, value           $ 1             389           $ 390
Stock option exercises, shares           510                         500
Stock-based compensation                         5,571           $ 5,571
Issuance of legal settlement, warrants, value                         2,863           2,863
Conversion of preferred stock to common stock           $ 3             (3)            
Conversion of preferred stock to common stock, shares (61)         3,200                          
Finance charges related to warrant issuance for surety bond backstop agreement                         6,585           6,585
Offering costs, stock and warrants                         (5,316)           (5,316)
Net loss                           (210,820)         (210,820)
Ending balance at May. 31, 2022           $ 720             $ 671,013 $ (766,131)         $ (94,398)
Ending balance, shares at May. 31, 2022 35         720,028   443