Consolidated Statement of Changes in Stockholders' (Deficit) Equity - USD ($) shares in Thousands, $ in Thousands |
Preferred Stock |
Common Stock
Private Warrant Exchange [Member]
|
Common Stock
Private Equity Offering
|
Common Stock |
Treasury Stock |
Additional Paid-in Capital
Private Warrant Exchange [Member]
|
Additional Paid-in Capital
Private Equity Offering
|
Additional Paid-in Capital |
Accumulated Deficit |
Private Warrant Exchange [Member] |
Private Equity Offering |
Total |
Beginning balance at May. 31, 2020 |
|
|
|
$ 519
|
|
|
|
$ 372,301
|
$ (375,301)
|
|
|
$ (2,481)
|
Beginning balance, shares at May. 31, 2020 |
109
|
|
|
519,261
|
286
|
|
|
|
|
|
|
|
Issuance of stock for convertible note repayment, value |
|
|
|
$ 2
|
|
|
|
9,535
|
|
|
|
9,537
|
Issuance of stock for convertible note, shares |
|
|
|
2,119
|
|
|
|
|
|
|
|
|
Stock issued via offering, tender or placement, value |
|
$ 17
|
|
|
|
$ 7,787
|
|
|
|
$ 7,804
|
|
|
Stock issued via offering, tender or placement, shares |
|
16,544
|
|
|
|
|
|
|
|
|
|
|
Offering costs, stock and warrants |
|
|
|
|
|
(364)
|
|
|
|
(364)
|
|
|
Inducement interest expense |
|
|
|
|
|
3,345
|
|
3,345
|
|
3,345
|
|
3,345
|
Dividend declared and paid |
|
|
|
|
|
|
|
|
(243)
|
|
|
(243)
|
Dividends accrued on preferred stock |
|
|
|
|
|
|
|
|
(420)
|
|
|
(420)
|
Stock-based compensation |
|
|
|
|
|
|
|
2,086
|
|
|
|
2,086
|
Warrant exercises, value |
|
|
|
$ 28
|
|
|
|
13,441
|
|
|
|
13,469
|
Warrant exercises, shares |
|
|
|
27,928
|
|
|
|
|
|
|
|
|
Stock issued for incentive compensation and tendered for income tax |
|
|
|
|
|
|
|
828
|
|
|
|
828
|
Stock issued for incentive compensation and tendered for income tax , shares |
|
|
|
323
|
156
|
|
|
|
|
|
|
|
Stock option exercises, value |
|
|
|
|
|
|
|
(39)
|
|
|
|
(39)
|
Stock option exercises, shares |
|
|
|
100
|
|
|
|
|
|
|
|
|
Equity instruments issued in legal settlement, value |
|
|
|
$ 4
|
|
|
|
(4)
|
|
|
|
|
Equity instruments issued in legal settlement, shares |
|
|
|
4,000
|
|
|
|
|
|
|
|
|
Conversion of Series B preferred stock to common stock, shares |
(5)
|
|
|
50
|
|
|
|
|
|
|
|
|
Net loss |
|
|
|
|
|
|
|
|
(30,832)
|
|
|
(30,832)
|
Ending balance at Aug. 31, 2020 |
|
|
|
$ 570
|
|
|
|
408,994
|
(406,796)
|
|
|
2,768
|
Ending balance, shares at Aug. 31, 2020 |
104
|
|
|
570,325
|
442
|
|
|
|
|
|
|
|
Beginning balance at May. 31, 2020 |
|
|
|
$ 519
|
|
|
|
372,301
|
(375,301)
|
|
|
(2,481)
|
Beginning balance, shares at May. 31, 2020 |
109
|
|
|
519,261
|
286
|
|
|
|
|
|
|
|
Net loss |
|
|
|
|
|
|
|
|
|
|
|
(66,257)
|
Ending balance at Nov. 30, 2020 |
|
|
|
$ 590
|
|
|
|
435,512
|
(442,636)
|
|
|
(6,534)
|
Ending balance, shares at Nov. 30, 2020 |
104
|
|
|
590,279
|
442
|
|
|
|
|
|
|
|
Beginning balance at May. 31, 2020 |
|
|
|
$ 519
|
|
|
|
372,301
|
(375,301)
|
|
|
(2,481)
|
Beginning balance, shares at May. 31, 2020 |
109
|
|
|
519,261
|
286
|
|
|
|
|
|
|
|
Net loss |
|
|
|
|
|
|
|
|
|
|
|
(111,463)
|
Ending balance at Feb. 28, 2021 |
|
|
|
|
|
|
|
472,029
|
(488,253)
|
|
|
(15,795)
|
Beginning balance at May. 31, 2020 |
|
|
|
$ 519
|
|
|
|
372,301
|
(375,301)
|
|
|
(2,481)
|
Beginning balance, shares at May. 31, 2020 |
109
|
|
|
519,261
|
286
|
|
|
|
|
|
|
|
Inducement interest expense |
|
|
|
|
|
|
|
13,922
|
|
|
|
13,922
|
Net loss |
|
|
|
|
|
|
|
|
(157,230)
|
|
|
(157,230)
|
Ending balance at May. 31, 2021 |
|
|
|
$ 626
|
|
|
|
512,796
|
(534,440)
|
|
|
(21,018)
|
Ending balance, shares at May. 31, 2021 |
96
|
|
|
626,123
|
443
|
|
|
|
|
|
|
|
Beginning balance at Aug. 31, 2020 |
|
|
|
$ 570
|
|
|
|
408,994
|
(406,796)
|
|
|
2,768
|
Beginning balance, shares at Aug. 31, 2020 |
104
|
|
|
570,325
|
442
|
|
|
|
|
|
|
|
Issuance of stock for convertible note repayment, value |
|
|
|
$ 4
|
|
|
|
11,549
|
|
|
|
11,553
|
Issuance of stock for convertible note, shares |
|
|
|
4,293
|
|
|
|
|
|
|
|
|
Stock issued via offering, tender or placement, value |
|
$ 13
|
$ 1
|
|
|
4,583
|
$ 999
|
|
|
4,596
|
$ 1,000
|
|
Stock issued via offering, tender or placement, shares |
|
12,480
|
667
|
|
|
|
|
|
|
|
|
|
Inducement interest expense |
|
|
|
|
|
4,217
|
|
4,217
|
|
4,217
|
|
4,217
|
Dividends accrued on preferred stock |
|
|
|
|
|
|
|
|
(415)
|
|
|
(415)
|
Stock-based compensation |
|
|
|
|
|
|
|
3,423
|
|
|
|
3,423
|
Warrant exercises, value |
|
|
|
$ 2
|
|
|
|
1,737
|
|
|
|
1,739
|
Warrant exercises, shares |
|
|
|
2,504
|
|
|
|
|
|
|
|
|
Stock option exercises, value |
|
|
|
|
|
|
|
10
|
|
|
|
10
|
Stock option exercises, shares |
|
|
|
10
|
|
|
|
|
|
|
|
|
Net loss |
|
|
|
|
|
|
|
|
(35,425)
|
|
|
(35,425)
|
Ending balance at Nov. 30, 2020 |
|
|
|
$ 590
|
|
|
|
435,512
|
(442,636)
|
|
|
(6,534)
|
Ending balance, shares at Nov. 30, 2020 |
104
|
|
|
590,279
|
442
|
|
|
|
|
|
|
|
Inducement interest expense |
|
|
|
|
|
|
|
5,360
|
|
|
|
5,360
|
Net loss |
|
|
|
|
|
|
|
|
(45,206)
|
|
|
(45,206)
|
Ending balance at Feb. 28, 2021 |
|
|
|
|
|
|
|
472,029
|
(488,253)
|
|
|
(15,795)
|
Ending balance at May. 31, 2021 |
|
|
|
$ 626
|
|
|
|
512,796
|
(534,440)
|
|
|
(21,018)
|
Ending balance, shares at May. 31, 2021 |
96
|
|
|
626,123
|
443
|
|
|
|
|
|
|
|
Issuance of stock for convertible note repayment, value |
|
|
|
$ 12
|
|
|
|
18,483
|
|
|
|
18,495
|
Issuance of stock for convertible note, shares |
|
|
|
11,816
|
|
|
|
|
|
|
|
|
Stock issued via offering, tender or placement, value |
|
$ 1
|
$ 3
|
|
|
774
|
2,869
|
|
|
775
|
2,872
|
|
Stock issued via offering, tender or placement, shares |
|
1,327
|
2,872
|
|
|
|
|
|
|
|
|
|
Inducement interest expense |
|
|
|
|
|
528
|
|
528
|
|
$ 528
|
|
528
|
Dividends accrued on preferred stock |
|
|
|
|
|
|
|
|
(420)
|
|
|
(420)
|
Stock-based compensation |
|
|
|
|
|
|
|
2,597
|
|
|
|
2,597
|
Warrant exercises, value |
|
|
|
$ 1
|
|
|
|
502
|
|
|
|
503
|
Warrant exercises, shares |
|
|
|
668
|
|
|
|
|
|
|
|
|
Stock issued for incentive compensation and tendered for income tax |
|
|
|
$ 1
|
|
|
|
(1)
|
|
|
|
|
Stock issued for incentive compensation and tendered for income tax , shares |
|
|
|
1,014
|
|
|
|
|
|
|
|
|
Stock option exercises, value |
|
|
|
|
|
|
|
189
|
|
|
|
189
|
Stock option exercises, shares |
|
|
|
300
|
|
|
|
|
|
|
|
|
Equity instruments issued in legal settlement, value |
|
|
|
|
|
|
|
1,744
|
|
|
|
1,744
|
Net loss |
|
|
|
|
|
|
|
|
(31,458)
|
|
|
(31,458)
|
Ending balance at Aug. 31, 2021 |
|
|
|
$ 644
|
|
|
|
540,481
|
(566,318)
|
|
|
(25,193)
|
Ending balance, shares at Aug. 31, 2021 |
96
|
|
|
644,120
|
443
|
|
|
|
|
|
|
|
Beginning balance at May. 31, 2021 |
|
|
|
$ 626
|
|
|
|
512,796
|
(534,440)
|
|
|
$ (21,018)
|
Beginning balance, shares at May. 31, 2021 |
96
|
|
|
626,123
|
443
|
|
|
|
|
|
|
|
Stock issued via offering, tender or placement, shares |
|
|
|
|
|
|
|
|
|
7,900
|
|
|
Equity instruments issued in legal settlement, shares |
|
|
|
|
|
|
|
|
|
|
|
1,600
|
Net loss |
|
|
|
|
|
|
|
|
|
|
|
$ (68,062)
|
Ending balance at Nov. 30, 2021 |
|
|
|
$ 686
|
|
|
|
589,971
|
(603,353)
|
|
|
(12,696)
|
Ending balance, shares at Nov. 30, 2021 |
36
|
|
|
685,861
|
443
|
|
|
|
|
|
|
|
Beginning balance at Aug. 31, 2021 |
|
|
|
$ 644
|
|
|
|
540,481
|
(566,318)
|
|
|
(25,193)
|
Beginning balance, shares at Aug. 31, 2021 |
96
|
|
|
644,120
|
443
|
|
|
|
|
|
|
|
Issuance of stock for convertible note repayment, value |
|
|
|
$ 8
|
|
|
|
11,505
|
|
|
|
11,513
|
Issuance of stock for convertible note, shares |
|
|
|
8,162
|
|
|
|
|
|
|
|
|
Stock issued via offering, tender or placement, value |
|
$ 7
|
$ 25
|
|
|
4,608
|
27,282
|
|
|
$ 4,615
|
27,307
|
|
Stock issued via offering, tender or placement, shares |
|
6,593
|
25,178
|
|
|
|
|
|
|
|
|
|
Offering costs, stock and warrants |
|
|
|
|
|
|
$ (1,418)
|
|
|
|
$ (1,418)
|
|
Dividend declared and paid |
|
|
|
35
|
|
|
|
|
|
|
|
|
Inducement interest expense |
|
|
|
|
|
$ 4,704
|
|
|
|
$ 4,704
|
|
|
Dividend declared and paid |
|
|
|
|
|
|
|
17
|
(17)
|
|
|
|
Dividends accrued on preferred stock |
|
|
|
|
|
|
|
|
(414)
|
|
|
(414)
|
Stock-based compensation |
|
|
|
|
|
|
|
2,060
|
|
|
|
2,060
|
Warrant exercises, value |
|
|
|
$ 1
|
|
|
|
532
|
|
|
|
533
|
Warrant exercises, shares |
|
|
|
963
|
|
|
|
|
|
|
|
|
Stock option exercises, value |
|
|
|
|
|
|
|
200
|
|
|
|
200
|
Stock option exercises, shares |
|
|
|
210
|
|
|
|
|
|
|
|
|
Conversion of Stock, Amount Issued |
|
|
|
$ 1
|
|
|
|
|
|
|
|
1
|
Conversion of Series B preferred stock to common stock, shares |
(60)
|
|
|
600
|
|
|
|
|
|
|
|
|
Net loss |
|
|
|
|
|
|
|
|
(36,604)
|
|
|
(36,604)
|
Ending balance at Nov. 30, 2021 |
|
|
|
$ 686
|
|
|
|
$ 589,971
|
$ (603,353)
|
|
|
$ (12,696)
|
Ending balance, shares at Nov. 30, 2021 |
36
|
|
|
685,861
|
443
|
|
|
|
|
|
|
|