Consolidated Statement of Changes in Stockholders' (Deficit) Equity - USD ($)
|
Total |
Exercise Price 1 |
Exercise Price 2 |
Preferred Stock [Member] |
Preferred Stock [Member]
Exercise Price 1
|
Preferred Stock [Member]
Exercise Price 2
|
Common Stock [Member] |
Common Stock [Member]
Exercise Price 1
|
Common Stock [Member]
Exercise Price 2
|
Treasury Stock [Member] |
Treasury Stock [Member]
Exercise Price 1
|
Treasury Stock [Member]
Exercise Price 2
|
Additional Paid-in Capital [Member] |
Additional Paid-in Capital [Member]
Exercise Price 1
|
Additional Paid-in Capital [Member]
Exercise Price 2
|
Accumulated Deficit [Member] |
Beginning balance at May. 31, 2016 |
$ 10,205,450
|
|
|
$ 95
|
|
|
$ 123,336
|
|
|
$ 0
|
|
|
$ 107,307,933
|
|
|
$ (97,225,914)
|
Beginning balance, shares at May. 31, 2016 |
|
|
|
95,100
|
|
|
123,335,634
|
|
|
0
|
|
|
|
|
|
|
Proceeds from registered direct offering |
14,044,252
|
|
|
|
|
|
$ 24,539
|
|
|
|
|
|
14,019,713
|
|
|
|
Proceeds from registered direct offering, shares |
|
|
|
|
|
|
24,538,994
|
|
|
|
|
|
|
|
|
|
Proceeds from private equity offering |
729,500
|
|
|
$ 0
|
|
|
$ 730
|
|
|
$ 0
|
|
|
728,770
|
|
|
|
Proceeds from private equity offering, shares |
|
|
|
0
|
|
|
729,500
|
|
|
0
|
|
|
|
|
|
|
Offering costs related to equity offering |
(1,804,249)
|
|
|
$ 0
|
|
|
$ 0
|
|
|
$ 0
|
|
|
(1,804,249)
|
|
|
|
Stock-based compensation |
1,204,791
|
|
|
0
|
|
|
0
|
|
|
0
|
|
|
1,204,791
|
|
|
|
Legal fees in connection with registered offerings |
(280,883)
|
|
|
0
|
|
|
0
|
|
|
0
|
|
|
(280,883)
|
|
|
|
Debt discount related to convertible notes payable |
91,389
|
|
|
0
|
|
|
0
|
|
|
0
|
|
|
91,389
|
|
|
|
Conversion of Series B Convertible Preferred |
|
|
|
$ (3)
|
|
|
$ 3
|
|
|
$ 0
|
|
|
|
|
|
|
Conversion of Series B Convertible Preferred, shares |
|
|
|
(3,000)
|
|
|
40,602
|
|
|
0
|
|
|
|
|
|
|
Interest expense related to warrant extension |
72,434
|
|
|
$ 0
|
|
|
$ 36
|
|
|
$ 0
|
|
|
72,398
|
|
|
|
Proceeds from warrant exercise |
|
$ 365,383
|
$ 32,500
|
|
$ 0
|
$ 0
|
|
$ 730
|
$ 44
|
|
$ 0
|
$ 0
|
|
$ 364,653
|
$ 32,456
|
|
Proceeds from warrant exercise, shares |
|
|
|
|
0
|
0
|
|
730,765
|
43,332
|
|
0
|
0
|
|
|
|
|
Cashless exercise of warrants |
|
|
|
$ 0
|
|
|
$ 50
|
|
|
$ 0
|
|
|
(50)
|
|
|
|
Cashless exercise of warrants, shares |
|
|
|
0
|
|
|
49,417
|
|
|
0
|
|
|
|
|
|
|
Net loss |
(25,763,801)
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
(25,763,801)
|
Ending balance at May. 31, 2017 |
(1,103,234)
|
|
|
$ 92
|
|
|
$ 149,468
|
|
|
$ 0
|
|
|
121,736,921
|
|
|
(122,989,715)
|
Ending balance, shares at May. 31, 2017 |
|
|
|
92,100
|
|
|
149,468,244
|
|
|
0
|
|
|
|
|
|
|
Proceeds from registered direct offering |
13,611,419
|
|
|
$ 0
|
|
|
$ 25,494
|
|
|
$ 0
|
|
|
13,585,925
|
|
|
|
Proceeds from registered direct offering, shares |
|
|
|
0
|
|
|
25,493,853
|
|
|
0
|
|
|
|
|
|
|
Offering costs related to registered direct offering, value |
(85,381)
|
|
|
$ 0
|
|
|
$ 0
|
|
|
$ 0
|
|
|
(857,149)
|
|
|
|
Offering costs related to registered direct offering, shares |
|
|
|
0
|
|
|
0
|
|
|
0
|
|
|
|
|
|
|
Proceeds from private equity offering |
17,643,451
|
|
|
$ 0
|
|
|
$ 35,286
|
|
|
$ 0
|
|
|
17,608,165
|
|
|
|
Proceeds from private equity offering, shares |
|
|
|
0
|
|
|
35,286,904
|
|
|
0
|
|
|
|
|
|
|
Offering costs related to private equity offering |
(1,717,597)
|
|
|
$ 0
|
|
|
$ 0
|
|
|
$ 0
|
|
|
(1,717,597)
|
|
|
|
Legal fees in connection with equity offerings |
(533,436)
|
|
|
0
|
|
|
0
|
|
|
0
|
|
|
(533,436)
|
|
|
|
Offering costs related to warrant tender offer |
(85,381)
|
|
|
0
|
|
|
0
|
|
|
0
|
|
|
(85,381)
|
|
|
|
Stock-based compensation |
1,290,777
|
|
|
0
|
|
|
0
|
|
|
0
|
|
|
1,290,777
|
|
|
|
Stock issued for board compensation |
260,190
|
|
|
0
|
|
|
0
|
|
|
0
|
|
|
260,190
|
|
|
|
Stock issued for bonuses and tendered for income tax, value |
104,546
|
|
|
$ 0
|
|
|
$ 311
|
|
|
$ (159)
|
|
|
104,394
|
|
|
|
Stock issued for bonuses and tendered for income tax, shares |
|
|
|
0
|
|
|
310,526
|
|
|
159,011
|
|
|
|
|
|
|
Debt discount related to convertible notes payable |
1,645,011
|
|
|
$ 0
|
|
|
$ 0
|
|
|
$ 0
|
|
|
1,645,011
|
|
|
|
Interest expense related to warrant extension |
826,252
|
|
|
0
|
|
|
0
|
|
|
0
|
|
|
826,252
|
|
|
|
Interest expense related to warrant tender offer |
393,685
|
|
|
0
|
|
|
0
|
|
|
0
|
|
|
393,685
|
|
|
|
Interest expense related to conversion of notes payable |
2,352,045
|
|
|
0
|
|
|
0
|
|
|
0
|
|
|
2,352,045
|
|
|
|
Proceeds from warrant exercise |
3,161,131
|
|
|
$ 0
|
|
|
$ 6,322
|
|
|
$ 0
|
|
|
3,154,809
|
|
|
|
Proceeds from warrant exercise, shares |
|
|
|
0
|
|
|
6,322,263
|
|
|
0
|
|
|
|
|
|
|
Net loss |
(50,149,681)
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
(50,149,681)
|
Ending balance at May. 31, 2018 |
(13,157,971)
|
|
|
$ 92
|
|
|
$ 216,881
|
|
|
$ (159)
|
|
|
159,764,611
|
|
|
(173,139,396)
|
Ending balance, shares at May. 31, 2018 |
|
|
|
92,100
|
|
|
216,881,790
|
|
|
159,011
|
|
|
|
|
|
|
Acquisition |
11,558,000
|
|
|
$ 0
|
|
|
$ 18,658
|
|
|
$ 0
|
|
|
11,539,342
|
|
|
|
Acquisition, share |
|
|
|
0
|
|
|
18,658,000
|
|
|
0
|
|
|
|
|
|
|
Issuance of stock payment shares |
0
|
|
|
|
|
|
$ 8,342
|
|
|
|
|
|
(8,342)
|
|
|
|
Issuance of stock payment shares, shares |
|
|
|
|
|
|
8,342,000
|
|
|
|
|
|
|
|
|
|
Issuance of stock for note payable redemption |
1,455,000
|
|
|
|
|
|
$ 3,757
|
|
|
|
|
|
1,451,243
|
|
|
|
Issuance of stock for note payable redemption ,shares |
|
|
|
|
|
|
3,756,406
|
|
|
|
|
|
|
|
|
|
Proceeds from registered direct offering |
11,814,739
|
|
|
|
|
|
$ 23,629
|
|
|
|
|
|
11,791,110
|
|
|
|
Proceeds from registered direct offering, shares |
|
|
|
|
|
|
23,629,480
|
|
|
|
|
|
|
|
|
|
Offering costs related to registered direct offering, value |
(1,129,516)
|
|
|
$ 0
|
|
|
$ 0
|
|
|
$ 0
|
|
|
(1,129,516)
|
|
|
|
Offering costs related to registered direct offering, shares |
|
|
|
0
|
|
|
0
|
|
|
0
|
|
|
|
|
|
|
Proceeds from private equity offering |
23,487,584
|
|
|
|
|
|
$ 46,976
|
|
|
|
|
|
23,440,608
|
|
|
|
Proceeds from private equity offering, shares |
|
|
|
|
|
|
46,975,170
|
|
|
|
|
|
|
|
|
|
Offering costs related to private equity offering |
(2,697,149)
|
|
|
$ 0
|
|
|
$ 0
|
|
|
$ 0
|
|
|
(2,697,149)
|
|
|
|
Offering costs related to debt offering |
260,636
|
|
|
0
|
|
|
0
|
|
|
0
|
|
|
260,636
|
|
|
|
Debt discount and issuance costs related to offering |
3,059,159
|
|
|
0
|
|
|
0
|
|
|
0
|
|
|
3,059,159
|
|
|
|
Beneficial conversion feature on note payable and relative fair value associated with warrants |
3,534,992
|
|
|
0
|
|
|
0
|
|
|
0
|
|
|
3,534,992
|
|
|
|
Proceeds from private warrant exchange |
2,966,512
|
|
|
$ 0
|
|
|
$ 11,312
|
|
|
$ 0
|
|
|
2,955,200
|
|
|
|
Proceeds from private warrant exchange, shares |
|
|
|
0
|
|
|
11,311,917
|
|
|
0
|
|
|
|
|
|
|
Offering costs related to private warrant exchange |
(266,986)
|
|
|
$ 0
|
|
|
$ 0
|
|
|
$ 0
|
|
|
(266,986)
|
|
|
|
Inducement interest expense on private warrant exchange |
195,927
|
|
|
0
|
|
|
0
|
|
|
0
|
|
|
195,927
|
|
|
|
Proceeds from Series C Convertible Preferred offering |
3,083,700
|
|
|
$ 3
|
|
|
$ 0
|
|
|
$ 0
|
|
|
3,083,697
|
|
|
|
Proceeds from Series C Convertible Preferred offering, shares |
|
|
|
3,246
|
|
|
0
|
|
|
0
|
|
|
|
|
|
|
Dividends on Series C Convertible Preferred shares |
(37,351)
|
|
|
$ 0
|
|
|
$ 0
|
|
|
$ 0
|
|
|
|
|
|
(37,351)
|
Legal fees in connection with equity offerings |
(242,771)
|
|
|
0
|
|
|
0
|
|
|
0
|
|
|
(242,771)
|
|
|
|
Stock-based compensation |
$ 3,388,095
|
|
|
0
|
|
|
0
|
|
|
0
|
|
|
3,388,095
|
|
|
|
Conversion of Series B Convertible Preferred, shares |
3,756,406
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Net loss |
$ (56,186,660)
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
(56,186,660)
|
Ending balance at May. 31, 2019 |
$ (8,914,060)
|
|
|
$ 95
|
|
|
$ 329,555
|
|
|
$ (159)
|
|
|
$ 220,119,856
|
|
|
$ (229,363,407)
|
Ending balance, shares at May. 31, 2019 |
|
|
|
95,346
|
|
|
329,554,763
|
|
|
159,011
|
|
|
|
|
|
|