Consolidated Statement of Changes in Stockholders' (Deficit) Equity - USD ($) shares in Thousands, $ in Thousands |
Total |
Private Placement [Member] |
Fiscal Year To Date |
Fiscal Year To Date
Private Placement [Member]
|
Preferred Stock [Member] |
Common Stock [Member] |
Common Stock [Member]
Private Placement [Member]
|
Treasury Stock [Member] |
Additional Paid-in Capital [Member] |
Additional Paid-in Capital [Member]
Private Placement [Member]
|
Accumulated Deficit [Member] |
Beginning balance at May. 31, 2019 |
$ (8,914)
|
|
$ (8,914)
|
|
|
$ 330
|
|
|
$ 220,120
|
|
$ (229,364)
|
Beginning balance, shares at May. 31, 2019 |
|
|
|
|
95
|
329,554
|
|
159
|
|
|
|
Issuance of stock for convertible note repayment |
1,005
|
|
1,005
|
|
|
$ 3
|
|
|
1,002
|
|
|
Issuance of stock for convertible note repayment, shares |
|
|
|
|
|
3,014
|
|
|
|
|
|
Dividends on Series C preferred shares |
(110)
|
|
|
|
|
|
|
|
|
|
(110)
|
Stock-based compensation |
581
|
|
581
|
|
|
|
|
|
581
|
|
|
Net loss |
(16,164)
|
|
(16,164)
|
|
|
|
|
|
|
|
(16,164)
|
Proceeds from registered direct offering |
2,256
|
|
2,256
|
|
|
$ 6
|
|
|
2,250
|
|
|
Proceeds from registered direct offering, shares |
|
|
|
|
|
5,640
|
|
|
|
|
|
Offering costs related to registered direct offering, value |
(260)
|
|
(260)
|
|
|
|
|
|
(260)
|
|
|
Inducement interest expense—public warrant tender offers |
2,430
|
|
2,430
|
|
|
|
|
|
2,430
|
|
|
Dividends on Series C preferred stock |
|
|
(110)
|
|
|
|
|
|
|
|
|
Legal fees in connection with equity offerings |
(16)
|
|
(16)
|
|
|
|
|
|
(16)
|
|
|
Proceeds from public warrant tender offers |
11,900
|
|
11,900
|
|
|
$ 45
|
|
|
11,855
|
|
|
Proceeds from public warrant tender offers (shares) |
|
|
|
|
|
45,376
|
|
|
|
|
|
Offering costs related to public warrant tender offers |
(1,058)
|
|
(1,058)
|
|
|
|
|
|
(1,058)
|
|
|
Proceeds from Series C preferred stock offering |
1,754
|
|
1,754
|
|
$ 2
|
|
|
|
1,754
|
|
|
Offering costs related to Series C preferred stock offering |
(198)
|
|
(198)
|
|
|
|
|
|
(198)
|
|
|
Ending balance at Aug. 31, 2019 |
(6,794)
|
|
(6,794)
|
|
|
$ 384
|
|
|
238,460
|
|
(245,638)
|
Ending balance, shares at Aug. 31, 2019 |
|
|
|
|
97
|
383,584
|
|
159
|
|
|
|
Beginning balance at May. 31, 2019 |
(8,914)
|
|
(8,914)
|
|
|
$ 330
|
|
|
220,120
|
|
(229,364)
|
Beginning balance, shares at May. 31, 2019 |
|
|
|
|
95
|
329,554
|
|
159
|
|
|
|
Net loss |
(31,024)
|
|
|
|
|
|
|
|
|
|
|
Ending balance at Nov. 30, 2019 |
(13,632)
|
|
(13,632)
|
|
|
$ 399
|
|
|
246,618
|
|
(260,649)
|
Ending balance, shares at Nov. 30, 2019 |
|
|
|
|
100
|
399,315
|
|
159
|
|
|
|
Beginning balance at May. 31, 2019 |
(8,914)
|
|
(8,914)
|
|
|
$ 330
|
|
|
220,120
|
|
(229,364)
|
Beginning balance, shares at May. 31, 2019 |
|
|
|
|
95
|
329,554
|
|
159
|
|
|
|
Ending balance at May. 31, 2020 |
(2,481)
|
|
(2,481)
|
|
|
$ 519
|
|
|
351,711
|
|
(354,711)
|
Ending balance, shares at May. 31, 2020 |
|
|
|
|
109
|
519,261
|
|
286
|
|
|
|
Beginning balance at Aug. 31, 2019 |
(6,794)
|
|
(6,794)
|
|
|
$ 384
|
|
|
238,460
|
|
(245,638)
|
Beginning balance, shares at Aug. 31, 2019 |
|
|
|
|
97
|
383,584
|
|
159
|
|
|
|
Issuance of stock for convertible note repayment |
740
|
|
1,745
|
|
|
$ 2
|
|
|
738
|
|
|
Issuance of stock for convertible note repayment, shares |
|
|
|
|
|
2,270
|
|
|
|
|
|
Note conversion and extension fees |
(217)
|
|
(217)
|
|
|
|
|
|
(217)
|
|
|
Inducement interest expense related to private warrant exchange |
|
|
2,713
|
|
|
|
|
|
|
|
|
Dividends on Series C preferred shares |
(151)
|
|
(261)
|
|
|
|
|
|
|
|
(151)
|
Stock-based compensation |
434
|
|
1,015
|
|
|
|
|
|
434
|
|
|
Net loss |
(14,860)
|
|
(31,024)
|
|
|
|
|
|
|
|
(14,860)
|
Proceeds from registered direct offering |
4,409
|
|
6,665
|
|
|
$ 13
|
|
|
4,396
|
|
|
Proceeds from registered direct offering, shares |
|
|
|
|
|
13,461
|
|
|
|
|
|
Offering costs related to registered direct offering, value |
(74)
|
|
(334)
|
|
|
|
|
|
(74)
|
|
|
Inducement interest expense—public warrant tender offers |
283
|
|
|
|
|
|
|
|
283
|
|
|
Proceeds from Series C Convertible Preferred offering |
|
|
4,542
|
|
|
|
|
|
|
|
|
Legal fees in connection with equity offerings |
|
|
(16)
|
|
|
|
|
|
|
|
|
Proceeds from public warrant tender offers |
|
|
11,900
|
|
|
$ 0
|
|
|
|
|
|
Proceeds from public warrant tender offers (shares) |
|
|
|
|
|
0
|
|
|
|
|
|
Offering costs related to public warrant tender offers |
|
|
(1,058)
|
|
|
|
|
|
|
|
|
Proceeds from Series C preferred stock offering |
2,788
|
|
|
|
$ 3
|
|
|
|
2,788
|
|
|
Offering costs related to Series C preferred stock offering |
(182)
|
|
(380)
|
|
|
|
|
|
(182)
|
|
|
Exercise of option to repurchase common stock |
(8)
|
|
(8)
|
|
|
|
|
|
(8)
|
|
|
Ending balance at Nov. 30, 2019 |
(13,632)
|
|
(13,632)
|
|
|
$ 399
|
|
|
246,618
|
|
(260,649)
|
Ending balance, shares at Nov. 30, 2019 |
|
|
|
|
100
|
399,315
|
|
159
|
|
|
|
Beginning balance at May. 31, 2020 |
(2,481)
|
|
(2,481)
|
|
|
$ 519
|
|
|
351,711
|
|
(354,711)
|
Beginning balance, shares at May. 31, 2020 |
|
|
|
|
109
|
519,261
|
|
286
|
|
|
|
Issuance of stock for convertible note repayment |
9,537
|
|
9,537
|
|
|
$ 2
|
|
|
9,535
|
|
|
Issuance of stock for convertible note repayment, shares |
|
|
|
|
|
2,119
|
|
|
|
|
|
Issuance of legal settlement shares |
|
|
|
|
|
$ 4
|
|
|
(4)
|
|
|
Issuance of legal settlement shares , shares |
|
|
|
|
|
4,000
|
|
|
|
|
|
Exercise of stock options |
39
|
|
39
|
|
|
|
|
|
39
|
|
|
Exercise of stock options, shares |
|
|
|
|
|
100
|
|
|
|
|
|
Stock issued for incentive compensation and tendered for income tax |
828
|
|
828
|
|
|
|
|
|
828
|
|
|
Stock issued for incentive compensation and tendered for income tax , shares |
|
|
|
|
|
323
|
|
156
|
|
|
|
Conversion of Series B preferred stock to common stock, shares |
|
|
|
|
(5)
|
50
|
|
|
|
|
|
Private warrant exchange |
7,804
|
|
7,804
|
|
|
$ 17
|
|
|
7,787
|
|
|
Private warrant exchange , shares |
|
|
|
|
|
16,544
|
|
|
|
|
|
Exercise of warrants |
13,469
|
|
13,469
|
|
|
$ 28
|
|
|
13,441
|
|
|
Exercise of warrants , shares |
|
|
|
|
|
27,928
|
|
|
|
|
|
Inducement interest expense related to private warrant exchange |
3,345
|
|
3,345
|
|
|
|
|
|
3,345
|
|
|
Offering costs related to private warrant exchange |
(364)
|
|
(364)
|
|
|
|
|
|
(364)
|
|
|
Dividend declared and paid on Series B preferred stock |
(243)
|
|
(243)
|
|
|
|
|
|
|
|
(243)
|
Dividends accrued on preferred stock |
(420)
|
|
(420)
|
|
|
|
|
|
|
|
(420)
|
Stock-based compensation |
2,086
|
|
2,086
|
|
|
|
|
|
2,086
|
|
|
Net loss |
(30,832)
|
|
(30,832)
|
|
|
|
|
|
|
|
(30,832)
|
Ending balance at Aug. 31, 2020 |
2,768
|
|
2,768
|
|
|
$ 570
|
|
|
388,404
|
|
(386,206)
|
Ending balance, shares at Aug. 31, 2020 |
|
|
|
|
104
|
570,325
|
|
442
|
|
|
|
Beginning balance at May. 31, 2020 |
(2,481)
|
|
(2,481)
|
|
|
$ 519
|
|
|
351,711
|
|
(354,711)
|
Beginning balance, shares at May. 31, 2020 |
|
|
|
|
109
|
519,261
|
|
286
|
|
|
|
Dividend declared and paid on Series B preferred stock |
|
|
(243)
|
|
|
|
|
|
|
|
|
Net loss |
(65,798)
|
|
|
|
|
|
|
|
|
|
|
Ending balance at Nov. 30, 2020 |
(6,534)
|
|
(6,534)
|
|
|
$ 590
|
|
|
414,463
|
|
(421,587)
|
Ending balance, shares at Nov. 30, 2020 |
|
|
|
|
104
|
590,279
|
|
442
|
|
|
|
Beginning balance at Aug. 31, 2020 |
2,768
|
|
2,768
|
|
|
$ 570
|
|
|
388,404
|
|
(386,206)
|
Beginning balance, shares at Aug. 31, 2020 |
|
|
|
|
104
|
570,325
|
|
442
|
|
|
|
Issuance of stock for convertible note repayment |
11,553
|
|
21,090
|
|
|
$ 4
|
|
|
11,549
|
|
|
Issuance of stock for convertible note repayment, shares |
|
|
|
|
|
4,293
|
|
|
|
|
|
Exercise of stock options |
10
|
|
49
|
|
|
|
|
|
10
|
|
|
Exercise of stock options, shares |
|
|
|
|
|
10
|
|
|
|
|
|
Stock issued for incentive compensation and tendered for income tax |
|
|
828
|
|
|
|
|
|
|
|
|
Stock issued for private offering |
|
$ 1,000
|
|
$ 1,000
|
|
|
$ 1
|
|
|
$ 999
|
|
Stock issued for private offering , Shares |
|
|
|
|
|
|
667
|
|
|
|
|
Private warrant exchange |
4,596
|
|
12,400
|
|
|
$ 13
|
|
|
4,583
|
|
|
Private warrant exchange , shares |
|
|
|
|
|
12,480
|
|
|
|
|
|
Exercise of warrants |
1,739
|
|
15,208
|
|
|
$ 2
|
|
|
1,737
|
|
|
Exercise of warrants , shares |
|
|
|
|
|
2,504
|
|
|
|
|
|
Inducement interest expense related to private warrant exchange |
|
|
7,103
|
|
|
|
|
|
|
|
|
Offering costs related to private warrant exchange |
|
|
(364)
|
|
|
|
|
|
|
|
|
Dividends accrued on preferred stock |
(415)
|
|
(835)
|
|
|
|
|
|
|
|
(415)
|
Stock-based compensation |
3,423
|
|
5,509
|
|
|
|
|
|
3,423
|
|
|
Net loss |
(34,966)
|
|
(65,798)
|
|
|
|
|
|
|
|
(34,966)
|
Offering costs related to registered direct offering, value |
0
|
|
|
|
|
|
|
|
0
|
|
|
Inducement interest expense—public warrant tender offers |
3,758
|
|
|
|
|
|
|
|
3,758
|
|
|
Ending balance at Nov. 30, 2020 |
$ (6,534)
|
|
$ (6,534)
|
|
|
$ 590
|
|
|
$ 414,463
|
|
$ (421,587)
|
Ending balance, shares at Nov. 30, 2020 |
|
|
|
|
104
|
590,279
|
|
442
|
|
|
|