Consolidated Statements of Changes in Stockholders' (Deficit) Equity - USD ($)
|
Total |
Private Equity Offering One |
Private Equity Offering Two |
Conversion Features One |
Conversion Features Two |
Conversion Features Three |
Conversion Features Four |
Exercise Price 1 |
Exercise Price 2 |
Preferred Stock |
Preferred Stock
Series B Convertible Preferred Stock
|
Common Stock |
Common Stock
Series B Convertible Preferred Stock
|
Common Stock
Private Equity Offering One
|
Common Stock
Private Equity Offering Two
|
Common Stock
Conversion Features Two
|
Common Stock
Conversion Features Three
|
Common Stock
Conversion Features Four
|
Common Stock
Exercise Price 1
|
Common Stock
Exercise Price 2
|
Treasury Stock |
Additional Paid-in Capital |
Additional Paid-in Capital
Private Equity Offering One
|
Additional Paid-in Capital
Private Equity Offering Two
|
Additional Paid-in Capital
Conversion Features One
|
Additional Paid-in Capital
Conversion Features Two
|
Additional Paid-in Capital
Conversion Features Three
|
Additional Paid-in Capital
Conversion Features Four
|
Additional Paid-in Capital
Exercise Price 1
|
Additional Paid-in Capital
Exercise Price 2
|
Accumulated Deficit |
Beginning balance at May. 31, 2015 |
$ (10,692,516)
|
|
|
|
|
|
|
|
|
$ 95
|
|
$ 63,644
|
|
|
|
|
|
|
|
|
|
$ 60,766,047
|
|
|
|
|
|
|
|
|
$ (71,522,302)
|
Beginning balance, shares at May. 31, 2015 |
|
|
|
|
|
|
|
|
|
95,100
|
|
63,644,348
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Debt discount due to reduction in note conversion price from ($0.75 to $0.675/share) |
329,524
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
329,524
|
|
|
|
|
|
|
|
|
|
Conversion of convertible debt and extinguishment of derivative liability, Value |
|
|
|
|
|
$ 4,732,514
|
|
|
|
|
|
|
|
|
|
|
$ 5,275
|
|
|
|
|
|
|
|
|
|
$ 4,727,239
|
|
|
|
|
Conversion of convertible debt and extinguishment of derivative liability, shares |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
$ 5,274,656
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Cashless exercise of warrants, shares |
|
|
|
|
|
|
|
|
|
|
|
74,490
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Cashless exercise of warrants, value |
|
|
|
|
|
|
|
|
|
|
|
$ 74
|
|
|
|
|
|
|
|
|
|
(74)
|
|
|
|
|
|
|
|
|
|
Stock-based compensation |
2,353,194
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
2,353,194
|
|
|
|
|
|
|
|
|
|
Deferred offering costs |
(3,915,127)
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
(3,915,127)
|
|
|
|
|
|
|
|
|
|
Proceeds from private equity offering, value |
|
$ 33,268,464
|
$ 4,301,500
|
|
|
|
|
|
|
|
|
|
|
$ 44,358
|
$ 4,302
|
|
|
|
|
|
|
|
$ 33,224,106
|
$ 4,297,198
|
|
|
|
|
|
|
|
Proceeds from private equity offering, shares |
|
|
|
|
|
|
|
|
|
|
|
|
|
44,357,838
|
4,301,500
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Proceeds from warrant exercise |
|
|
|
|
|
|
|
$ 96,154
|
$ 452,465
|
|
|
|
|
|
|
|
|
|
$ 192
|
$ 604
|
|
|
|
|
|
|
|
|
$ 95,962
|
$ 451,861
|
|
Proceeds from warrant exercise, shares |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
192,307
|
603,286
|
|
|
|
|
|
|
|
|
|
|
|
Interest expense related to warrant extension |
|
|
|
$ 757,871
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
$ 757,871
|
|
|
|
|
|
|
Modification of warrants to related conversion inducement |
|
|
|
$ 866,713
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
$ 866,713
|
|
|
|
|
|
|
Common shares issued to extinguish promissory notes payable, convertible debt and related interest, shares |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
4,095,008
|
|
792,201
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Common shares issued to extinguish promissory notes payable, convertible debt and related interest, value |
|
|
|
|
$ 2,764,154
|
|
$ 594,152
|
|
|
|
|
|
|
|
|
$ 4,095
|
|
$ 792
|
|
|
|
|
|
|
|
$ 2,760,059
|
|
$ 593,360
|
|
|
|
Net (loss) at year ended |
(25,703,612)
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
(25,703,612)
|
Ending balance at May. 31, 2016 |
10,205,450
|
|
|
|
|
|
|
|
|
$ 95
|
|
$ 123,336
|
|
|
|
|
|
|
|
|
|
107,307,933
|
|
|
|
|
|
|
|
|
(97,225,914)
|
Ending balance, shares at May. 31, 2016 |
|
|
|
|
|
|
|
|
|
95,100
|
|
123,335,634
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Cashless exercise of warrants, shares |
|
|
|
|
|
|
|
|
|
|
|
49,417
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Cashless exercise of warrants, value |
|
|
|
|
|
|
|
|
|
|
|
$ 50
|
|
|
|
|
|
|
|
|
|
(50)
|
|
|
|
|
|
|
|
|
|
Stock-based compensation |
1,204,791
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
1,204,791
|
|
|
|
|
|
|
|
|
|
Proceeds from private equity offering, value |
|
|
$ 729,500
|
|
|
|
|
|
|
|
|
|
|
|
$ 730
|
|
|
|
|
|
|
|
|
$ 728,770
|
|
|
|
|
|
|
|
Proceeds from private equity offering, shares |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
729,500
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Offering costs related to equity offering |
(1,804,249)
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
(1,804,249)
|
|
|
|
|
|
|
|
|
|
Proceeds from registered direct offering |
14,044,252
|
|
|
|
|
|
|
|
|
|
|
$ 24,539
|
|
|
|
|
|
|
|
|
|
14,019,713
|
|
|
|
|
|
|
|
|
|
Proceeds from registered direct offering, shares |
|
|
|
|
|
|
|
|
|
|
|
24,538,994
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Proceeds from warrant exercise |
|
|
|
|
|
|
|
$ 365,383
|
$ 32,500
|
|
|
|
|
|
|
|
|
|
$ 730
|
$ 44
|
|
|
|
|
|
|
|
|
$ 364,653
|
$ 32,456
|
|
Proceeds from warrant exercise, shares |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
730,765
|
43,332
|
|
|
|
|
|
|
|
|
|
|
|
Debt discount related to convertible notes payable |
91,389
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
91,389
|
|
|
|
|
|
|
|
|
|
Interest expense related to warrant extension |
72,434
|
|
|
|
|
|
|
|
|
|
|
$ 36
|
|
|
|
|
|
|
|
|
|
72,398
|
|
|
|
|
|
|
|
|
|
Legal fees in connection with registered offerings |
(280,883)
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
(280,883)
|
|
|
|
|
|
|
|
|
|
Common shares issued to extinguish promissory notes payable, convertible debt and related interest, shares |
|
|
|
|
|
|
|
|
|
|
(3,000)
|
|
40,602
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Common shares issued to extinguish promissory notes payable, convertible debt and related interest, value |
|
|
|
|
|
|
|
|
|
|
$ (3)
|
|
$ 3
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Net (loss) at year ended |
(25,763,801)
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
(25,763,801)
|
Ending balance at May. 31, 2017 |
(1,103,234)
|
|
|
|
|
|
|
|
|
$ 92
|
|
$ 149,468
|
|
|
|
|
|
|
|
|
|
121,736,921
|
|
|
|
|
|
|
|
|
(122,989,715)
|
Ending balance, shares at May. 31, 2017 |
|
|
|
|
|
|
|
|
|
92,100
|
|
149,468,244
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Stock-based compensation |
1,290,777
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
1,290,777
|
|
|
|
|
|
|
|
|
|
Stock issued for board compensation |
260,190
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
260,190
|
|
|
|
|
|
|
|
|
|
Stock issued for bonuses and tendered for income tax, value |
104,546
|
|
|
|
|
|
|
|
|
|
|
$ 311
|
|
|
|
|
|
|
|
|
$ (159)
|
104,394
|
|
|
|
|
|
|
|
|
|
Stock issued for bonuses and tendered for income tax, shares |
|
|
|
|
|
|
|
|
|
|
|
310,526
|
|
|
|
|
|
|
|
|
159,011
|
|
|
|
|
|
|
|
|
|
|
Proceeds from private equity offering, value |
17,643,451
|
|
|
|
|
|
|
|
|
|
|
$ 35,286
|
|
|
|
|
|
|
|
|
|
17,608,165
|
|
|
|
|
|
|
|
|
|
Proceeds from private equity offering, shares |
|
|
|
|
|
|
|
|
|
|
|
35,286,904
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Offering costs related to private equity offering, value |
(1,717,597)
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
(1,717,597)
|
|
|
|
|
|
|
|
|
|
Proceeds from registered direct offering |
13,611,419
|
|
|
|
|
|
|
|
|
|
|
$ 25,494
|
|
|
|
|
|
|
|
|
|
13,585,925
|
|
|
|
|
|
|
|
|
|
Proceeds from registered direct offering, shares |
|
|
|
|
|
|
|
|
|
|
|
25,493,853
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Offering costs related to registered direct offering |
(857,149)
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
(857,149)
|
|
|
|
|
|
|
|
|
|
Offering costs related to registered direct offering, value |
|
|
|
|
|
|
|
|
|
$ 0
|
|
$ 0
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Offering costs related to registered direct offering, shares |
|
|
|
|
|
|
|
|
|
0
|
|
0
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Legal fees in connection with equity offerings |
(533,436)
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
(533,436)
|
|
|
|
|
|
|
|
|
|
Proceeds from warrant exercise |
3,161,132
|
|
|
|
|
|
|
|
|
|
|
$ 6,322
|
|
|
|
|
|
|
|
|
|
3,154,810
|
|
|
|
|
|
|
|
|
|
Proceeds from warrant exercise, shares |
|
|
|
|
|
|
|
|
|
|
|
6,322,263
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Offering costs related to warrant tender offer |
(85,382)
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
(85,382)
|
|
|
|
|
|
|
|
|
|
Debt discount related to convertible notes payable |
1,645,011
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
1,645,011
|
|
|
|
|
|
|
|
|
|
Interest expense related to warrant extension |
826,252
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
826,252
|
|
|
|
|
|
|
|
|
|
Interest expense related to warrant tender offer |
393,685
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
393,685
|
|
|
|
|
|
|
|
|
|
Interest expense related to conversion of notes payable |
2,352,045
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
2,352,045
|
|
|
|
|
|
|
|
|
|
Net (loss) at year ended |
(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
|
|
|
|
|
|
|
|
|
|
|