Consolidated Statement of Changes in Stockholders Deficit - USD ($) shares in Thousands, $ in Thousands |
Preferred Stock
Series B Convertible Preferred Stock
|
Preferred Stock
Series C Convertible Preferred Stock
|
Preferred Stock |
Common Stock
Series B Convertible Preferred Stock
|
Common Stock
Series C Convertible Preferred Stock
|
Common Stock
Private Warrant Exchange [Member]
|
Common Stock
Private Equity Offering
|
Common Stock |
Treasury Stock |
Additional Paid-in Capital
Series C Convertible Preferred Stock
|
Additional Paid-in Capital
Private Warrant Exchange [Member]
|
[1] |
Additional Paid-in Capital
Private Equity Offering
|
Additional Paid-in Capital |
Accumulated Deficit |
Series B Convertible Preferred Stock |
[1] |
Private Warrant Exchange [Member] |
Private Equity Offering |
Total |
Beginning balance at May. 31, 2021 |
|
|
|
|
|
|
|
|
$ 626
|
|
|
|
|
|
$ 532,031
|
[1] |
$ (553,675)
|
[1] |
|
|
|
|
|
$ (21,018)
|
[1] |
Beginning balance (shares) at May. 31, 2021 |
|
|
|
96
|
|
|
|
|
626,123
|
443
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Issuance of stock for convertible note repayment |
|
|
|
|
|
|
|
|
$ 12
|
|
|
|
|
|
13,832
|
[1] |
|
|
|
|
|
|
|
13,844
|
[1] |
Issuance of stock for convertible note repayment (in shares) |
|
|
|
|
|
|
|
|
11,816
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Loss on induced conversion |
[1] |
|
|
|
|
|
|
|
|
|
|
|
|
|
18,530
|
|
|
|
|
|
|
|
|
18,530
|
|
Issuance of legal settlement, warrants |
[1] |
|
|
|
|
|
|
|
|
|
|
|
|
|
1,744
|
|
|
|
|
|
|
|
|
1,744
|
|
Stock option exercises |
[1] |
|
|
|
|
|
|
|
|
|
|
|
|
|
189
|
|
|
|
|
|
|
|
|
189
|
|
Stock option exercises (in shares) |
|
|
|
|
|
|
|
|
300
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Stock issued for compensation and tendered for income tax |
|
|
|
|
|
|
|
|
$ 1
|
|
|
|
|
|
(1)
|
[1] |
|
|
|
|
|
|
|
|
|
Stock issued for compensation and tendered for income tax (in shares) |
|
|
|
|
|
|
|
|
1,014
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Stock issued for private offerings |
|
|
|
|
|
|
|
$ 3
|
|
|
|
|
$ 2,869
|
[1] |
|
|
|
|
|
|
|
$ 2,872
|
[1] |
|
|
Stock issued for private offerings (in shares) |
|
|
|
|
|
|
|
2,872
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Warrant exercises |
|
|
|
|
|
|
$ 1
|
|
$ 1
|
|
|
$ 774
|
|
|
502
|
[1] |
|
|
|
$ 775
|
[1] |
|
|
503
|
[1] |
Warrant exercises (in shares) |
|
|
|
|
|
|
1,327
|
|
668
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Inducement interest expense related to private warrant exchange |
[1] |
|
|
|
|
|
|
|
|
|
|
|
|
|
528
|
|
|
|
|
|
|
|
|
528
|
|
Dividends accrued on Series C and D convertible preferred stock |
[1] |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
(420)
|
|
|
|
|
|
|
(420)
|
|
Stock-based compensation |
[1] |
|
|
|
|
|
|
|
|
|
|
|
|
|
2,597
|
|
|
|
|
|
|
|
|
2,597
|
|
Net loss |
[1] |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
(45,337)
|
|
|
|
|
|
|
(45,337)
|
|
Ending balance at Aug. 31, 2021 |
|
|
|
|
|
|
|
|
$ 644
|
|
|
|
|
|
573,595
|
[1] |
(599,432)
|
[1] |
|
|
|
|
|
(25,193)
|
[1] |
Ending balance (shares) at Aug. 31, 2021 |
|
|
|
96
|
|
|
|
|
644,120
|
443
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Beginning balance at May. 31, 2021 |
|
|
|
|
|
|
|
|
$ 626
|
|
|
|
|
|
532,031
|
[1] |
(553,675)
|
[1] |
|
|
|
|
|
(21,018)
|
[1] |
Beginning balance (shares) at May. 31, 2021 |
|
|
|
96
|
|
|
|
|
626,123
|
443
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Loss on induced conversion |
[1] |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
25,315
|
|
Net loss |
[1],[2] |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
(85,414)
|
|
Ending balance at Nov. 30, 2021 |
|
|
|
|
|
|
|
|
$ 686
|
|
|
|
|
|
626,558
|
[1] |
(639,940)
|
[1] |
|
|
|
|
|
(12,696)
|
[1] |
Ending balance (shares) at Nov. 30, 2021 |
|
|
|
36
|
|
|
|
|
685,861
|
443
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Beginning balance at May. 31, 2021 |
|
|
|
|
|
|
|
|
$ 626
|
|
|
|
|
|
532,031
|
[1] |
(553,675)
|
[1] |
|
|
|
|
|
(21,018)
|
[1] |
Beginning balance (shares) at May. 31, 2021 |
|
|
|
96
|
|
|
|
|
626,123
|
443
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Ending balance at May. 31, 2022 |
|
|
|
|
|
|
|
|
$ 720
|
|
|
|
|
|
671,013
|
|
(766,131)
|
|
|
|
|
|
|
(94,398)
|
|
Ending balance (shares) at May. 31, 2022 |
|
|
|
35
|
|
|
|
|
720,028
|
443
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Beginning balance at Aug. 31, 2021 |
|
|
|
|
|
|
|
|
$ 644
|
|
|
|
|
|
573,595
|
[1] |
(599,432)
|
[1] |
|
|
|
|
|
(25,193)
|
[1] |
Beginning balance (shares) at Aug. 31, 2021 |
|
|
|
96
|
|
|
|
|
644,120
|
443
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Issuance of stock for convertible note repayment |
|
|
|
|
|
|
|
|
$ 8
|
|
|
|
|
|
8,193
|
[1] |
|
|
|
|
|
|
|
8,201
|
[1] |
Issuance of stock for convertible note repayment (in shares) |
|
|
|
|
|
|
|
|
8,162
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Loss on induced conversion |
[1] |
|
|
|
|
|
|
|
|
|
|
|
|
|
6,785
|
|
|
|
|
|
|
|
|
6,785
|
|
Stock option exercises |
[1] |
|
|
|
|
|
|
|
|
|
|
|
|
|
200
|
|
|
|
|
|
|
|
|
200
|
|
Stock option exercises (in shares) |
|
|
|
|
|
|
|
|
210
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Stock issued for private offerings |
|
|
|
|
|
|
|
$ 25
|
|
|
|
|
27,282
|
[1] |
|
|
|
|
|
|
|
27,307
|
[1] |
|
|
Stock issued for private offerings (in shares) |
|
|
|
|
|
|
|
25,178
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Issuance costs related to stock issued for private offerings |
[1] |
|
|
|
|
|
|
|
|
|
|
|
|
|
(1,418)
|
|
|
|
|
|
|
|
|
(1,418)
|
|
Conversion of preferred stock to common stock |
|
|
|
|
$ 1
|
|
|
|
|
|
|
|
|
|
|
|
|
|
$ 1
|
|
|
|
|
|
|
Conversion of preferred stock to common stock (in shares) |
|
(60)
|
|
|
600
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Warrant exercises |
|
|
|
|
|
|
$ 7
|
|
$ 1
|
|
|
$ 4,608
|
|
|
532
|
[1] |
|
|
|
$ 4,615
|
[1] |
|
|
533
|
[1] |
Warrant exercises (in shares) |
|
|
|
|
|
|
6,593
|
|
963
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Inducement interest expense related to private warrant exchange |
[1] |
|
|
|
|
|
|
|
|
|
|
|
|
|
4,704
|
|
|
|
|
|
|
|
|
4,704
|
|
Dividends accrued on Series C and D convertible preferred stock |
[1] |
|
|
|
|
|
|
|
|
|
|
|
|
|
17
|
|
(431)
|
|
|
|
|
|
|
(414)
|
|
Dividends accrued on Series C and D convertible preferred stock (in shares) |
|
|
|
|
|
|
|
|
35
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Stock-based compensation |
[1] |
|
|
|
|
|
|
|
|
|
|
|
|
|
2,060
|
|
|
|
|
|
|
|
|
2,060
|
|
Net loss |
[1] |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
(40,077)
|
|
|
|
|
|
|
(40,077)
|
[2] |
Ending balance at Nov. 30, 2021 |
|
|
|
|
|
|
|
|
$ 686
|
|
|
|
|
|
626,558
|
[1] |
(639,940)
|
[1] |
|
|
|
|
|
(12,696)
|
[1] |
Ending balance (shares) at Nov. 30, 2021 |
|
|
|
36
|
|
|
|
|
685,861
|
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
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
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
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
4,600
|
|
Issuance costs related to stock issued for private offerings |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
(6,289)
|
|
|
|
|
|
|
|
|
$ (6,289)
|
|
Conversion of preferred stock to common stock |
|
|
|
|
|
$ 1
|
|
|
|
|
$ (1)
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Conversion of preferred stock to common stock (in shares) |
|
|
(1)
|
|
|
1,136
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
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 share) |
|
|
|
|
|
|
|
|
4,620
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Dividends accrued on Series C and D convertible preferred stock |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
(384)
|
|
|
|
|
|
|
|
|
(384)
|
|
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
|
|
Warrant exercises (in shares) |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
500
|
|
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 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
|
|
|
|
|
|
|
|
|
|
|
9,700
|
|
|
|
|
|
Make-whole shares related to private warrant exchange (in shares) |
|
|
|
|
|
|
|
|
23
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Dividend paid in common stock upon conversion of Series C convertible preferred stock ($0.50 per share) |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
159
|
|
|
|
|
|
|
|
|
159
|
|
Dividend paid in common stock upon conversion of Series C convertible preferred stock ($0.50 per share) (in shares) |
|
|
|
|
|
|
|
|
319
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Dividends accrued on Series C and D convertible preferred stock |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
(369)
|
|
|
|
|
|
|
|
|
(369)
|
|
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
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|