Consolidated Statement of Changes in Stockholders' (Deficit) Equity - USD ($)
|
Total |
Exercise Price 1 |
Preferred Stock [Member] |
Preferred Stock [Member]
Exercise Price 1
|
Common Stock [Member] |
Common Stock [Member]
Exercise Price 1
|
Treasury Stock [Member] |
Treasury Stock [Member]
Exercise Price 1
|
Additional Paid-in Capital [Member] |
Additional Paid-in Capital [Member]
Exercise Price 1
|
Accumulated Deficit [Member] |
| Beginning balance at May. 31, 2017 |
$ (1,103,234)
|
|
$ 92
|
|
$ 149,468
|
|
$ 0
|
|
$ 121,736,921
|
|
$ (122,989,715)
|
| Beginning 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 |
(857,149)
|
|
$ 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 |
|
|
$ 0
|
|
$ 0
|
|
$ 0
|
|
|
|
|
| Offering costs related to equity offering |
(1,717,597)
|
|
|
|
|
|
|
|
(1,717,597)
|
|
|
| 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
|
|
|
|
|
| Legal fees in connection with registered offerings |
(533,436)
|
|
|
|
|
|
|
|
(533,436)
|
|
|
| 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
|
|
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
|
$ 0
|
$ 0
|
$ 6,322
|
$ 0
|
$ 0
|
|
$ 3,154,809
|
|
| Proceeds from warrant exercise, shares |
|
|
0
|
0
|
0
|
6,322,263
|
0
|
0
|
|
|
|
| Offering costs related to public warrant tender offers |
(85,381)
|
|
$ 0
|
|
$ 0
|
|
$ 0
|
|
(85,381)
|
|
|
| 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
|
|
$ 0
|
|
$ 8,342
|
|
$ 0
|
|
(8,342)
|
|
|
| Issuance of stock payment shares, shares |
|
|
0
|
|
8,342,000
|
|
0
|
|
|
|
|
| Issuance of stock for note payable redemptions and conversions |
1,455,000
|
|
$ 0
|
|
$ 3,757
|
|
$ 0
|
|
1,451,243
|
|
|
| Issuance of stock for note payable redemptions and conversions , shares |
|
|
0
|
|
3,756,406
|
|
0
|
|
|
|
|
| Proceeds from registered direct offering |
11,814,739
|
|
$ 0
|
|
$ 23,629
|
|
$ 0
|
|
11,791,110
|
|
|
| Proceeds from registered direct offering, shares |
|
|
0
|
|
23,629,480
|
|
0
|
|
|
|
|
| Offering costs related to registered direct offering, value |
(1,129,516)
|
|
$ 0
|
|
|
|
$ 0
|
|
(1,129,516)
|
|
|
| Offering costs related to registered direct offering, shares |
|
|
0
|
|
|
|
0
|
|
|
|
|
| Proceeds from private equity offering |
23,487,584
|
|
$ 0
|
|
$ 46,976
|
|
$ 0
|
|
23,440,608
|
|
|
| Proceeds from private equity offering, shares |
|
|
0
|
|
46,975,170
|
|
0
|
|
|
|
|
| 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
|
|
|
| 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
|
|
|
|
|
| Issuance of stock for note payable redemptions and conversions |
10,822,188
|
|
$ 0
|
|
$ 22,967
|
|
$ 0
|
|
$ 10,799,221
|
|
|
| Issuance of stock for note payable redemptions and conversions , shares |
|
|
0
|
|
22,967,227
|
|
|
|
0
|
|
|
| Proceeds from registered direct offering |
12,665,799
|
|
$ 0
|
|
$ 38,857
|
|
$ 0
|
|
$ 12,626,942
|
|
|
| Proceeds from registered direct offering, shares |
|
|
0
|
|
38,856,094
|
|
0
|
|
|
|
|
| Offering costs related to registered direct offering, value |
(377,859)
|
|
$ 0
|
|
|
|
$ 0
|
|
(377,859)
|
|
|
| Offering costs related to registered direct offering, shares |
|
|
0
|
|
|
|
0
|
|
|
|
|
| Proceeds from private warrant exchange |
6,021,093
|
|
$ 0
|
|
$ 20,527
|
|
$ 0
|
|
6,000,566
|
|
|
| Proceeds from private warrant exchange, shares |
|
|
0
|
|
20,528,745
|
|
0
|
|
|
|
|
| Offering costs related to private warrant exchange |
(197,253)
|
|
$ 0
|
|
$ 0
|
|
$ 0
|
|
(197,253)
|
|
|
| Inducement interest expense on private warrant exchange |
5,191,338
|
|
0
|
|
0
|
|
0
|
|
$ 5,191,338
|
|
|
| Proceeds from Series C Convertible Preferred offering |
|
|
$ 5
|
|
$ 0
|
|
0
|
|
|
|
|
| Proceeds from Series C Convertible Preferred offering, shares |
|
|
4,957
|
|
0
|
|
|
|
0
|
|
|
| Legal fees in connection with equity offerings |
(15,877)
|
|
$ 0
|
|
$ 0
|
|
0
|
|
$ (15,877)
|
|
|
| Offering costs related to warrant tender offer |
(1,058,466)
|
|
|
|
|
|
|
|
(1,058,466)
|
|
|
| Stock-based compensation |
6,547,803
|
|
$ 0
|
|
0
|
|
0
|
|
6,547,803
|
|
|
| Stock issued for bonuses and tendered for income tax, value |
$ 154,552
|
|
|
|
$ 380
|
|
$ (127)
|
|
$ 154,299
|
|
|
| Stock issued for bonuses and tendered for income tax, shares |
|
|
|
|
379,880
|
|
126,997
|
|
|
|
|
| Proceeds from warrant exercise |
|
$ 20,500,115
|
|
$ 0
|
|
$ 42,024
|
|
$ 0
|
|
$ 20,458,091
|
|
| Proceeds from warrant exercise, shares |
|
|
|
0
|
|
42,023,872
|
|
0
|
|
|
|
| Note conversion and extension fees |
3,899,205
|
|
0
|
|
8,232
|
|
0
|
|
3,890,973
|
|
|
| Note conversion and extension fees, Shares |
|
|
|
|
8,232,006
|
|
|
|
|
|
|
| Relative fair market value associated with warrants exercised |
$ 11,948,972
|
|
$ 0
|
|
$ 0
|
|
$ 0
|
|
$ 11,948,972
|
|
|
| Proceeds from public warrant tender offers |
11,900,260
|
|
|
|
$ 45,376
|
|
|
|
11,854,884
|
|
|
| Proceeds from public warrant tender offers (shares) |
|
|
|
|
45,375,923
|
|
|
|
|
|
|
| Offering costs related to public warrant tender offers |
(1,058,466)
|
|
|
|
|
|
|
|
(1,058,466)
|
|
|
| Proceeds from Series C Preferred offering |
4,957,000
|
|
|
|
|
|
|
|
4,956,995
|
|
|
| Offering costs related to Series C Preferred offering |
(432,368)
|
|
0
|
|
$ 0
|
|
0
|
|
(432,368)
|
|
|
| Dividends on Series C Preferred shares |
(671,971)
|
|
0
|
|
0
|
|
0
|
|
0
|
|
(671,971)
|
| Proceeds from Series D Preferred offering |
8,452,000
|
|
$ 8
|
|
$ 0
|
|
0
|
|
$ 8,451,992
|
|
|
| Proceeds from Series D Preferred offering , shares |
|
|
8,452
|
|
0
|
|
|
|
0
|
|
|
| Offering costs related to Series D Preferred offering |
(4,645)
|
|
$ 0
|
|
$ 0
|
|
0
|
|
$ (4,645)
|
|
|
| Dividends on Series D Preferred shares |
(272,115)
|
|
0
|
|
0
|
|
0
|
|
|
|
(272,115)
|
| Exercise of option to repurchase common stock |
(8,342)
|
|
0
|
|
0
|
|
0
|
|
(8,342)
|
|
|
| Exercise of stock options |
5,602,541
|
|
|
|
$ 8,724
|
|
|
|
5,593,817
|
|
|
| Exercise of stock options, shares |
|
|
|
|
8,723,070
|
|
|
|
|
|
|
| Stock issued for services |
|
|
|
|
$ 2,620
|
|
|
|
(2,620)
|
|
|
| Stock issued for services, shares |
|
|
|
|
2,620,000
|
|
|
|
|
|
|
| Inducement interest expense - tender offers and debt conversions |
2,713,014
|
|
|
|
|
|
|
|
2,713,014
|
|
|
| Legal settlement |
(22,500,000)
|
|
|
|
|
|
|
|
22,500,000
|
|
|
| Net loss |
(124,403,402)
|
|
|
|
|
|
|
|
|
|
(124,403,402)
|
| Ending balance at May. 31, 2020 |
$ (2,480,478)
|
|
$ 108
|
|
$ 519,262
|
|
$ (286)
|
|
$ 351,711,333
|
|
$ (354,710,895)
|
| Ending balance, shares at May. 31, 2020 |
|
|
108,755
|
|
519,261,580
|
|
286,008
|
|
|
|
|