Summary of Significant Accounting Policies - Summary of the impact by financial statement line item of corrections (Details) - USD ($) $ / shares in Units, $ in Thousands |
3 Months Ended | 6 Months Ended | 9 Months Ended | 12 Months Ended | ||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Feb. 28, 2023 |
Nov. 30, 2022 |
Aug. 31, 2022 |
Feb. 28, 2022 |
Nov. 30, 2021 |
Aug. 31, 2021 |
Feb. 28, 2021 |
Nov. 30, 2020 |
Nov. 30, 2021 |
Nov. 30, 2020 |
Feb. 28, 2023 |
Feb. 28, 2022 |
Feb. 28, 2021 |
May 31, 2022 |
May 31, 2021 |
May 31, 2020 |
May 31, 2019 |
May 31, 2018 |
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| Summary Of Significant Accounting Policies [Line Items] | ||||||||||||||||||||||||||
| Inducement interest expense | $ (954) | [1] | $ (528) | $ (5,360) | $ (4,217) | $ (7,562) | $ (6,186) | [1] | $ (12,922) | $ (6,691) | $ (13,922) | |||||||||||||||
| Total interest and other expense | (21,888) | $ (14,755) | (23,700) | (6,796) | (13,477) | $ (38,455) | (18,637) | (60,343) | (25,433) | (71,869) | ||||||||||||||||
| Loss before income taxes | $ (13,702) | (41,285) | [1] | (40,077) | (45,337) | (37,581) | (37,980) | (85,414) | (68,812) | $ (61,188) | (126,699) | [1] | (106,393) | (210,820) | (176,465) | |||||||||||
| Net loss | $ (13,702) | $ (26,495) | $ (20,991) | $ (41,285) | [1],[2] | $ (40,077) | [1] | $ (45,337) | [1] | $ (37,581) | $ (37,980) | $ (85,414) | $ (68,812) | $ (61,188) | $ (126,699) | [1],[2] | $ (106,393) | $ (210,820) | $ (176,465) | |||||||
| Basic loss per share | $ (0.02) | $ (0.06) | [1],[2] | $ (0.06) | $ (0.07) | $ (0.07) | $ (0.07) | $ (0.13) | $ (0.12) | $ (0.08) | $ (0.19) | [1],[2] | $ (0.18) | $ (0.31) | $ (0.30) | |||||||||||
| Diluted loss per share | $ (0.02) | $ (0.06) | $ (0.06) | $ (0.07) | $ (0.07) | $ (0.07) | $ (0.13) | $ (0.12) | $ (0.08) | $ (0.19) | $ (0.18) | $ (0.31) | $ (0.30) | |||||||||||||
| Additional paid-in capital | $ 715,207 | $ 658,449 | $ 626,558 | $ 573,595 | $ 466,779 | $ 438,067 | $ 626,558 | $ 438,067 | $ 715,207 | $ 658,449 | $ 466,779 | $ 671,013 | $ 532,031 | |||||||||||||
| Accumulated deficit | (823,054) | (681,622) | (639,940) | (599,432) | (483,183) | (445,191) | (639,940) | (445,191) | $ (823,054) | (681,622) | (483,183) | (766,131) | (553,675) | |||||||||||||
| Adjustments | $ 15,533 | $ 4,532 | $ 525 | |||||||||||||||||||||||
| Accumulated Deficit | ||||||||||||||||||||||||||
| Summary Of Significant Accounting Policies [Line Items] | ||||||||||||||||||||||||||
| Net loss | $ (13,702) | $ (26,495) | $ (20,991) | (41,285) | [1] | (40,077) | [1] | (45,337) | [1] | $ (210,820) | (176,465) | |||||||||||||||
| Restatement Adjustment Inducement Expense | ||||||||||||||||||||||||||
| Summary Of Significant Accounting Policies [Line Items] | ||||||||||||||||||||||||||
| Inducement interest expense | (13,922) | |||||||||||||||||||||||||
| Total interest and other expense | (52,634) | |||||||||||||||||||||||||
| Loss before income taxes | (157,230) | |||||||||||||||||||||||||
| Net loss | $ (157,230) | |||||||||||||||||||||||||
| Basic loss per share | $ (0.27) | |||||||||||||||||||||||||
| Additional paid-in capital | $ 512,796 | |||||||||||||||||||||||||
| Accumulated deficit | (534,440) | |||||||||||||||||||||||||
| Previously Reported | ||||||||||||||||||||||||||
| Summary Of Significant Accounting Policies [Line Items] | ||||||||||||||||||||||||||
| Inducement interest expense | (9) | (4,139) | (3,758) | (7,103) | (11,242) | (11,366) | ||||||||||||||||||||
| Total interest and other expense | (12,931) | (11,282) | (9,302) | (13,200) | (10,463) | (21,103) | (15,623) | (34,034) | (28,823) | (50,078) | ||||||||||||||||
| Loss before income taxes | (32,328) | (36,604) | (30,939) | (43,985) | (34,966) | (67,543) | (65,798) | (99,871) | (109,783) | (154,674) | ||||||||||||||||
| Net loss | $ (32,328) | $ (36,604) | $ (30,939) | $ (43,985) | $ (34,966) | $ (67,543) | $ (65,798) | $ (99,871) | $ (109,783) | $ (154,674) | ||||||||||||||||
| Basic loss per share | $ (0.05) | $ (0.06) | $ (0.05) | $ (0.08) | $ (0.06) | $ (0.11) | $ (0.12) | $ (0.15) | $ (0.18) | $ (0.27) | ||||||||||||||||
| Diluted loss per share | $ (0.05) | $ (0.06) | $ (0.05) | $ (0.08) | $ (0.06) | $ (0.11) | $ (0.12) | $ (0.15) | $ (0.18) | $ (0.27) | ||||||||||||||||
| Additional paid-in capital | $ 612,905 | $ 589,971 | $ 516,816 | $ 449,579 | $ 414,463 | $ 589,971 | $ 414,463 | $ 612,905 | $ 449,579 | $ 489,650 | ||||||||||||||||
| Accumulated deficit | (636,078) | (603,353) | (542,653) | (465,983) | (421,587) | (603,353) | (421,587) | (636,078) | (465,983) | (511,294) | ||||||||||||||||
| Previously Reported | Restatement Adjustment Inducement Expense | ||||||||||||||||||||||||||
| Summary Of Significant Accounting Policies [Line Items] | ||||||||||||||||||||||||||
| Inducement interest expense | (11,366) | |||||||||||||||||||||||||
| Total interest and other expense | (50,078) | |||||||||||||||||||||||||
| Loss before income taxes | (154,674) | |||||||||||||||||||||||||
| Net loss | $ (154,674) | |||||||||||||||||||||||||
| Basic loss per share | $ (0.27) | |||||||||||||||||||||||||
| Additional paid-in capital | $ 489,650 | |||||||||||||||||||||||||
| Accumulated deficit | (511,294) | |||||||||||||||||||||||||
| Adjustments | ||||||||||||||||||||||||||
| Summary Of Significant Accounting Policies [Line Items] | ||||||||||||||||||||||||||
| Inducement interest expense | (519) | (1,221) | (459) | (459) | (1,680) | (2,556) | ||||||||||||||||||||
| Total interest and other expense | (8,957) | (3,473) | (14,398) | 6,404 | (3,014) | (17,352) | (3,014) | (26,309) | 3,390 | (21,791) | ||||||||||||||||
| Loss before income taxes | (8,957) | (3,473) | (14,398) | 6,404 | (3,014) | (17,871) | (3,014) | (26,828) | 3,390 | (21,791) | ||||||||||||||||
| Net loss | $ (8,957) | $ (3,473) | $ (14,398) | $ 6,404 | $ (3,014) | $ (17,871) | $ (3,014) | $ (26,828) | $ 3,390 | $ (21,791) | ||||||||||||||||
| Basic loss per share | $ (0.01) | $ 0.00 | $ (0.02) | $ 0.01 | $ (0.01) | $ (0.02) | $ 0.00 | $ (0.04) | $ 0.00 | $ (0.03) | ||||||||||||||||
| Diluted loss per share | $ (0.01) | $ 0.00 | $ (0.02) | $ 0.01 | $ (0.01) | $ (0.02) | $ 0.00 | $ (0.04) | $ 0.00 | $ (0.03) | ||||||||||||||||
| Additional paid-in capital | $ 45,544 | $ 36,587 | $ 56,779 | $ 17,200 | $ 23,604 | $ 36,587 | $ 23,604 | $ 45,544 | $ 17,200 | $ 42,381 | ||||||||||||||||
| Accumulated deficit | $ (45,544) | $ (36,587) | $ (56,779) | $ (17,200) | $ (23,604) | $ (36,587) | $ (23,604) | $ (45,544) | $ (17,200) | (42,381) | ||||||||||||||||
| Adjustments | Restatement Adjustment Inducement Expense | ||||||||||||||||||||||||||
| Summary Of Significant Accounting Policies [Line Items] | ||||||||||||||||||||||||||
| Inducement interest expense | (2,556) | |||||||||||||||||||||||||
| Total interest and other expense | (2,556) | |||||||||||||||||||||||||
| Loss before income taxes | (2,556) | |||||||||||||||||||||||||
| Net loss | (2,556) | |||||||||||||||||||||||||
| Additional paid-in capital | 23,146 | |||||||||||||||||||||||||
| Accumulated deficit | $ (23,146) | |||||||||||||||||||||||||
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