Consolidated Statements of Stockholders' Deficit - USD ($) shares in Thousands, $ in Thousands |
Preferred Stock |
Common Stock
Private Warrant Exchange
|
Common Stock
Private Equity Offering
|
Common Stock |
Treasury Stock |
Additional Paid-in Capital
Private Warrant Exchange
|
Additional Paid-in Capital
Private Equity Offering
|
Additional Paid-in Capital |
Accumulated Deficit |
Private Warrant Exchange |
Private Equity Offering |
Total |
Beginning balance at May. 31, 2021 |
|
|
|
$ 626
|
|
|
|
$ 532,031
|
$ (553,675)
|
|
|
$ (21,018)
|
Beginning balance (shares) at May. 31, 2021 |
96
|
|
|
626,123
|
443
|
|
|
|
|
|
|
|
Issuance of stock for convertible note repayment |
|
|
|
$ 37
|
|
|
|
68,344
|
|
|
|
68,381
|
Issuance of stock for convertible note repayment (in shares) |
|
|
|
37,110
|
|
|
|
|
|
|
|
|
Loss on induced conversion |
|
|
|
|
|
|
|
|
|
|
|
37,381
|
Issuance of legal settlement, warrants |
|
|
|
|
|
|
|
2,863
|
|
|
|
2,863
|
Stock option exercises |
|
|
|
$ 1
|
|
|
|
389
|
|
|
|
390
|
Stock option exercises (in shares) |
|
|
|
510
|
|
|
|
|
|
|
|
|
Stock issued for compensation and tendered for income tax |
|
|
|
$ 2
|
|
|
|
666
|
|
|
|
668
|
Stock issued for compensation and tendered for income tax (in shares) |
|
|
|
2,582
|
|
|
|
|
|
|
|
|
Stock issued for private offerings |
|
|
$ 38
|
|
|
|
$ 46,473
|
|
|
|
$ 46,511
|
|
Stock issued for private offerings (in shares) |
|
|
38,035
|
|
|
|
|
|
|
|
|
|
Offering costs related to stock issuance |
|
|
|
|
|
|
|
(5,316)
|
|
|
|
(5,316)
|
Conversion of preferred stock to common stock |
|
|
|
$ 3
|
|
|
|
(3)
|
|
|
|
|
Conversion of preferred stock to common stock (in shares) |
(61)
|
|
|
3,200
|
|
|
|
|
|
|
|
|
Warrant exercises |
|
$ 8
|
|
$ 2
|
|
$ 5,382
|
|
1,034
|
|
$ 5,390
|
|
1,036
|
Warrant exercises (in shares) |
|
7,920
|
|
1,642
|
|
|
|
|
|
|
|
|
Inducement interest expense related to private warrant exchange |
|
|
|
$ 2
|
|
|
|
6,689
|
|
|
|
6,691
|
Inducement interest expense related to private warrant exchange (in shares) |
|
|
|
2,293
|
|
|
|
|
|
|
|
|
Preferred stock dividends accrued and paid in common stock Preferred stock dividends accrued and paid in common stock upon conversion |
|
|
|
$ 1
|
|
|
|
305
|
(1,636)
|
|
|
(1,330)
|
Preferred stock dividends accrued and paid in common stock Preferred stock dividends accrued and paid in common stock upon conversion (in shares) |
|
|
|
(613)
|
|
|
|
|
|
|
|
|
Stock-based compensation |
|
|
|
|
|
|
|
5,571
|
|
|
|
5,571
|
Finance charges related to warrant issuance for surety bond backstop agreement |
|
|
|
|
|
|
|
6,585
|
|
|
|
6,585
|
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
|
|
|
|
|
|
|
|
Stock issued for compensation |
|
|
|
$ 1
|
|
|
|
344
|
|
|
|
345
|
Stock issued for compensation (in shares) |
|
|
|
879
|
|
|
|
|
|
|
|
|
Stock issued for private offerings |
|
|
$ 85
|
|
|
|
17,459
|
|
|
|
17,544
|
|
Stock issued for private offerings (in shares) |
|
|
85,378
|
|
|
|
|
|
|
|
|
|
Warrant exercises |
|
|
|
$ 1
|
|
|
|
263
|
|
|
|
264
|
Warrant exercises (in shares) |
|
|
|
657
|
|
|
|
|
|
|
|
|
Deemed dividend paid in common stock due to down round provision, recorded in additional paid-in capital |
|
|
|
$ (5)
|
|
|
|
5
|
|
|
|
|
Deemed dividend paid in common stock due to down round provision recorded in additional paid-in capital (in shares) |
|
|
|
4,620
|
|
|
|
|
|
|
|
|
Reclassification of warrants from liability to equity classified |
|
|
|
|
|
|
|
8,601
|
|
|
|
8,601
|
Stock-based compensation |
|
|
|
|
|
|
|
996
|
|
|
|
996
|
Reclassification of prior period preferred stock dividends |
|
|
|
|
|
|
|
(4,265)
|
4,265
|
|
|
|
Net loss |
|
|
|
|
|
|
|
|
(20,991)
|
|
|
(20,991)
|
Ending balance at Aug. 31, 2022 |
|
|
|
$ 813
|
|
|
|
687,732
|
(782,857)
|
|
|
(94,312)
|
Ending balance (shares) at Aug. 31, 2022 |
34
|
|
|
812,698
|
443
|
|
|
|
|
|
|
|
Beginning balance at May. 31, 2022 |
|
|
|
$ 720
|
|
|
|
671,013
|
(766,131)
|
|
|
(94,398)
|
Beginning balance (shares) at May. 31, 2022 |
35
|
|
|
720,028
|
443
|
|
|
|
|
|
|
|
Loss on induced conversion |
|
|
|
|
|
|
|
|
|
|
|
638
|
Net loss |
|
|
|
|
|
|
|
|
|
|
|
(47,486)
|
Ending balance at Nov. 30, 2022 |
|
|
|
$ 825
|
|
|
|
692,558
|
(809,352)
|
|
|
(115,969)
|
Ending balance (shares) at Nov. 30, 2022 |
34
|
|
|
825,279
|
443
|
|
|
|
|
|
|
|
Beginning balance at May. 31, 2022 |
|
|
|
$ 720
|
|
|
|
671,013
|
(766,131)
|
|
|
(94,398)
|
Beginning balance (shares) at May. 31, 2022 |
35
|
|
|
720,028
|
443
|
|
|
|
|
|
|
|
Issuance of stock for convertible note repayment |
|
|
|
$ 17
|
|
|
|
3,983
|
|
|
|
4,000
|
Issuance of stock for convertible note repayment (in shares) |
|
|
|
17,260
|
|
|
|
|
|
|
|
|
Loss on induced conversion |
|
|
|
|
|
|
|
5,312
|
|
|
|
5,312
|
Warrants issued in note offering |
|
|
|
|
|
|
|
114
|
|
|
|
114
|
Stock issued for compensation |
|
|
|
$ 3
|
|
|
|
982
|
|
|
|
985
|
Stock issued for compensation (in shares) |
|
|
|
2,751
|
|
|
|
|
|
|
|
|
Exercise of warrants, net of offering costs (in shares) |
|
|
|
|
|
|
|
|
|
9,700
|
|
|
Make-whole shares related to private warrant exchange (in shares) |
|
|
|
23
|
|
|
|
|
|
|
|
|
Stock issued for private offerings |
|
|
$ 157
|
|
|
|
$ 37,067
|
|
|
|
$ 37,224
|
|
Stock issued for private offerings (in shares) |
|
|
157,390
|
|
|
|
|
|
|
500
|
4,600
|
|
Offering costs related to stock issuance |
|
|
|
|
|
|
|
(1,760)
|
|
|
|
(1,760)
|
Conversion of preferred stock to common stock |
|
|
|
$ 1
|
|
|
|
(1)
|
|
|
|
|
Conversion of preferred stock to common stock (in shares) |
(1)
|
|
|
1,136
|
|
|
|
|
|
|
|
|
Warrant exercises |
|
$ 13
|
|
$ 2
|
|
$ 2,794
|
|
437
|
|
$ 2,807
|
|
439
|
Warrant exercises (in shares) |
|
13,094
|
|
1,898
|
|
|
|
|
|
|
|
|
Deemed dividend paid in common stock due to down round provision, recorded in additional paid-in capital |
|
|
|
$ 6
|
|
|
|
(6)
|
|
|
|
|
Deemed dividend paid in common stock due to down round provision recorded in additional paid-in capital (in shares) |
|
|
|
5,154
|
|
|
|
|
|
|
|
|
Preferred stock dividends accrued and paid in common stock Preferred stock dividends accrued and paid in common stock upon conversion |
|
|
|
|
|
|
|
(1,331)
|
|
|
|
(1,331)
|
Preferred stock dividends accrued and paid in common stock Preferred stock dividends accrued and paid in common stock upon conversion (in shares) |
|
|
|
(319)
|
|
|
|
|
|
|
|
|
Reclassification of warrants from liability to equity classified |
|
|
|
|
|
|
|
8,756
|
|
|
|
8,756
|
Stock-based compensation |
|
|
|
|
|
|
|
3,290
|
|
|
|
3,290
|
Reclassification of prior period preferred stock dividends |
|
|
|
|
|
|
|
(4,265)
|
4,265
|
|
|
|
Finance charges related to warrant issuance for surety bond backstop agreement |
|
|
|
|
|
|
|
4,885
|
|
|
|
4,885
|
Net loss |
|
|
|
|
|
|
|
|
(79,824)
|
|
|
(79,824)
|
Ending balance at May. 31, 2023 |
|
|
|
$ 919
|
|
|
|
731,270
|
(841,690)
|
|
|
(109,501)
|
Ending balance (shares) at May. 31, 2023 |
34
|
|
|
919,053
|
443
|
|
|
|
|
|
|
|
Beginning balance at Aug. 31, 2022 |
|
|
|
$ 813
|
|
|
|
687,732
|
(782,857)
|
|
|
(94,312)
|
Beginning balance (shares) at Aug. 31, 2022 |
34
|
|
|
812,698
|
443
|
|
|
|
|
|
|
|
Issuance of stock for convertible note repayment |
|
|
|
$ 2
|
|
|
|
498
|
|
|
|
500
|
Issuance of stock for convertible note repayment (in shares) |
|
|
|
1,822
|
|
|
|
|
|
|
|
|
Loss on induced conversion |
|
|
|
|
|
|
|
638
|
|
|
|
638
|
Stock issued for compensation |
|
|
|
|
|
|
|
310
|
|
|
|
310
|
Stock issued for compensation (in shares) |
|
|
|
765
|
|
|
|
|
|
|
|
|
Exercise of warrants, net of offering costs |
|
|
|
$ 10
|
|
|
|
2,123
|
|
|
|
2,133
|
Exercise of warrants, net of offering costs (in shares) |
|
|
|
9,652
|
|
|
|
|
|
|
|
|
Make-whole shares related to private warrant exchange (in shares) |
|
|
|
23
|
|
|
|
|
|
|
|
|
Stock-based compensation |
|
|
|
|
|
|
|
1,467
|
|
|
|
1,467
|
Net loss |
|
|
|
|
|
|
|
|
(26,495)
|
|
|
(26,495)
|
Ending balance at Nov. 30, 2022 |
|
|
|
$ 825
|
|
|
|
692,558
|
(809,352)
|
|
|
(115,969)
|
Ending balance (shares) at Nov. 30, 2022 |
34
|
|
|
825,279
|
443
|
|
|
|
|
|
|
|
Beginning balance at May. 31, 2023 |
|
|
|
$ 919
|
|
|
|
731,270
|
(841,690)
|
|
|
(109,501)
|
Beginning balance (shares) at May. 31, 2023 |
34
|
|
|
919,053
|
443
|
|
|
|
|
|
|
|
Issuance of stock for convertible note repayment |
|
|
|
$ 8
|
|
|
|
1,492
|
|
|
|
1,500
|
Issuance of stock for convertible note repayment (in shares) |
|
|
|
8,661
|
|
|
|
|
|
|
|
|
Loss on induced conversion |
|
|
|
|
|
|
|
2,004
|
|
|
|
2,004
|
Warrants issued in note offering |
|
|
|
|
|
|
|
170
|
|
|
|
170
|
Stock issued for compensation |
|
|
|
$ 1
|
|
|
|
154
|
|
|
|
155
|
Stock issued for compensation (in shares) |
|
|
|
686
|
|
|
|
|
|
|
|
|
Warrant exercises |
|
|
|
$ 3
|
|
|
|
297
|
|
|
|
300
|
Warrant exercises (in shares) |
|
|
|
3,000
|
|
|
|
|
|
|
|
|
Reclassification of warrants from liability to equity classified |
|
|
|
|
|
|
|
79
|
|
|
|
79
|
Stock-based compensation |
|
|
|
|
|
|
|
348
|
|
|
|
348
|
Net loss |
|
|
|
|
|
|
|
|
(11,571)
|
|
|
(11,571)
|
Ending balance at Aug. 31, 2023 |
|
|
|
$ 931
|
|
|
|
735,441
|
(853,261)
|
|
|
(116,889)
|
Ending balance (shares) at Aug. 31, 2023 |
34
|
|
|
931,400
|
443
|
|
|
|
|
|
|
|
Beginning balance at May. 31, 2023 |
|
|
|
$ 919
|
|
|
|
731,270
|
(841,690)
|
|
|
(109,501)
|
Beginning balance (shares) at May. 31, 2023 |
34
|
|
|
919,053
|
443
|
|
|
|
|
|
|
|
Loss on induced conversion |
|
|
|
|
|
|
|
|
|
|
|
2,640
|
Net loss |
|
|
|
|
|
|
|
|
|
|
|
(21,134)
|
Ending balance at Nov. 30, 2023 |
|
|
|
$ 971
|
|
|
|
747,472
|
(862,824)
|
|
|
(114,381)
|
Ending balance (shares) at Nov. 30, 2023 |
34
|
|
|
971,286
|
443
|
|
|
|
|
|
|
|
Beginning balance at Aug. 31, 2023 |
|
|
|
$ 931
|
|
|
|
735,441
|
(853,261)
|
|
|
(116,889)
|
Beginning balance (shares) at Aug. 31, 2023 |
34
|
|
|
931,400
|
443
|
|
|
|
|
|
|
|
Issuance of stock for convertible note repayment |
|
|
|
$ 4
|
|
|
|
496
|
|
|
|
500
|
Issuance of stock for convertible note repayment (in shares) |
|
|
|
3,535
|
|
|
|
|
|
|
|
|
Loss on induced conversion |
|
|
|
|
|
|
|
636
|
|
|
|
636
|
Warrants issued in note offering |
|
|
|
|
|
|
|
10
|
|
|
|
10
|
Stock issued for compensation |
|
|
|
$ 1
|
|
|
|
97
|
|
|
|
98
|
Stock issued for compensation (in shares) |
|
|
|
559
|
|
|
|
|
|
|
|
|
Stock issued for private offerings |
|
|
|
$ 21
|
|
|
|
6,307
|
|
|
|
6,328
|
Stock issued for private offerings (in shares) |
|
|
|
21,453
|
|
|
|
|
|
|
|
|
Stock-based compensation |
|
|
|
|
|
|
|
474
|
|
|
|
474
|
Net loss |
|
|
|
|
|
|
|
|
(9,563)
|
|
|
(9,563)
|
Ending balance at Nov. 30, 2023 |
|
|
|
$ 971
|
|
|
|
$ 747,472
|
$ (862,824)
|
|
|
$ (114,381)
|
Ending balance (shares) at Nov. 30, 2023 |
34
|
|
|
971,286
|
443
|
|
|
|
|
|
|
|