Note 2 - Summary of Significant Accounting Policies - Restatement of Previously Issued Consolidated Financial Statements (Details) - USD ($) $ / shares in Units, $ in Thousands |
1 Months Ended | 2 Months Ended | 3 Months Ended | 5 Months Ended | 6 Months Ended | 8 Months Ended | 9 Months Ended | 11 Months Ended | 12 Months Ended | ||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Dec. 05, 2018 |
Jan. 31, 2019 |
Jul. 31, 2020 |
Apr. 30, 2020 |
Jan. 31, 2020 |
Jul. 31, 2019 |
Apr. 30, 2019 |
Apr. 30, 2019 |
Apr. 30, 2020 |
Jul. 31, 2019 |
Jul. 31, 2020 |
Oct. 31, 2019 |
Oct. 31, 2020 |
|
| Warrant liability | $ 29,040 | $ 6,639 | $ 3,905 | $ 7,160 | $ 13,018 | $ 17,574 | $ 17,574 | $ 3,905 | $ 13,018 | $ 6,639 | $ 6,769 | $ 7,031 | |
| Total liabilities | 492,875 | 498,391 | 520,471 | 521,796 | 537,640 | 501,750 | 501,750 | 520,471 | 537,640 | 498,391 | 529,319 | 481,648 | |
| Additional paid-in capital | 246,463 | 360,434 | 359,077 | 357,694 | 354,594 | 275,584 | 275,584 | 359,077 | 354,594 | 360,434 | 356,227 | 367,681 | |
| Accumulated deficit | (28,336) | (97,190) | (97,438) | (41,724) | (45,437) | (52,755) | (52,755) | (97,438) | (45,437) | (97,190) | (38,589) | (99,840) | |
| Total stockholders' equity | 217,573 | 264,126 | 258,701 | 317,216 | 302,721 | 220,926 | 220,926 | 258,701 | 302,721 | 264,126 | 317,045 | 267,110 | |
| Change in fair value of warrant liabilities | $ 0 | (2,522) | (2,734) | 3,254 | (391) | 4,556 | (14,774) | (17,296) | 2,864 | (12,740) | 130 | (6,491) | (261) |
| Total other income (expense) | (18,033) | (8,103) | (11,062) | (5,477) | (9,825) | (5,259) | (24,072) | (32,175) | (15,301) | (37,434) | (26,502) | (41,324) | (34,500) |
| Income (loss) before income taxes | (26,767) | (8,917) | (215) | (57,935) | (4,284) | 5,396 | (22,847) | (31,764) | (62,218) | (26,368) | (62,432) | (19,706) | (66,228) |
| Net loss | $ (22,575) | $ (6,152) | $ 247 | $ (55,714) | $ (3,137) | $ 7,318 | $ (24,419) | $ (30,571) | $ (58,850) | $ (23,253) | $ (58,603) | $ (16,403) | $ (61,251) |
| Basic (in dollars per share) | $ (3.00) | $ (0.22) | $ (0.00) | $ (1.06) | $ (0.07) | $ 0.14 | $ (0.85) | $ (1.08) | $ (1.13) | $ (0.66) | $ (1.14) | $ (0.43) | $ (1.20) |
| Diluted (in dollars per share) | $ (3.00) | $ (0.22) | $ (0.00) | $ (1.06) | $ (0.07) | $ 0.13 | $ (0.85) | $ (1.08) | $ (1.13) | $ (0.66) | $ (1.14) | $ (0.43) | $ (1.20) |
| Increase (decrease) in fair value of warrant liabilities | $ (0) | $ 2,522 | $ 2,734 | $ (3,254) | $ 391 | $ (4,556) | $ 14,774 | $ 17,296 | $ (2,864) | $ 12,740 | $ (130) | $ 6,491 | $ 261 |
| Net cash provided by operating activities | (12,949) | 1,814 | (4,090) | 26,987 | 1,425 | 53,484 | 22,777 | 78,970 | |||||
| Previously Reported [Member] | |||||||||||||
| Warrant liability | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | |
| Total liabilities | 463,835 | 491,752 | 516,566 | 514,636 | 524,622 | 484,176 | 484,176 | 516,566 | 524,622 | 491,752 | 522,550 | 474,617 | |
| Additional paid-in capital | 261,808 | 354,696 | 353,339 | 351,956 | 348,856 | 269,846 | 269,846 | 353,339 | 348,856 | 354,696 | 350,489 | 361,943 | |
| Accumulated deficit | (14,641) | (84,814) | (87,795) | (28,827) | (26,682) | (29,444) | (29,444) | (87,795) | (26,682) | (84,814) | (26,081) | (87,071) | |
| Total stockholders' equity | 5,000 | 246,613 | 270,765 | 262,606 | 324,376 | 315,739 | 238,500 | 238,500 | 262,606 | 315,739 | 270,765 | 323,815 | 274,141 |
| Change in fair value of warrant liabilities | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | |
| Total other income (expense) | (5,581) | (8,328) | (8,731) | (9,434) | (9,815) | (9,298) | (14,879) | (18,165) | (24,694) | (26,632) | (34,833) | (34,239) | |
| Income (loss) before income taxes | (6,395) | 2,519 | (61,189) | (3,893) | 840 | (8,073) | (14,468) | (65,082) | (13,628) | (62,562) | (13,215) | (65,967) | |
| Net loss | $ (3,630) | $ 2,981 | $ (58,968) | $ (2,746) | $ 2,762 | $ (9,645) | $ (13,275) | $ (61,714) | $ (10,513) | $ (58,733) | $ (9,912) | $ (60,990) | |
| Basic (in dollars per share) | $ (0.14) | $ 0.05 | $ (1.13) | $ (0.06) | $ 0.05 | $ (0.35) | $ (0.48) | $ (1.19) | $ (0.31) | $ (1.14) | $ (0.28) | $ (1.19) | |
| Diluted (in dollars per share) | $ (0.14) | $ 0.04 | $ (1.13) | $ (0.06) | $ 0.05 | $ (0.35) | $ (0.48) | $ (1.19) | $ (0.31) | $ (1.14) | $ (0.28) | $ (1.19) | |
| Increase (decrease) in fair value of warrant liabilities | $ (0) | $ (0) | $ (0) | $ (0) | $ (0) | $ (0) | $ (0) | $ (0) | $ (0) | $ (0) | $ (0) | $ (0) | |
| Net cash provided by operating activities | (12,949) | 1,814 | (4,090) | 26,987 | 1,425 | 53,484 | 22,777 | 78,970 | |||||
| Revision of Prior Period, Adjustment [Member] | |||||||||||||
| Warrant liability | 29,040 | 6,639 | 3,905 | 7,160 | 13,018 | 17,574 | 17,574 | 3,905 | 13,018 | 6,639 | 6,769 | 7,031 | |
| Total liabilities | 29,040 | 6,639 | 3,905 | 7,160 | 13,018 | 17,574 | 17,574 | 3,905 | 13,018 | 6,639 | 6,769 | 7,031 | |
| Additional paid-in capital | (15,345) | 5,738 | 5,738 | 5,738 | 5,738 | 5,738 | 5,738 | 5,738 | 5,738 | 5,738 | 5,738 | 5,738 | |
| Accumulated deficit | (13,695) | (12,376) | (9,643) | (12,897) | (18,755) | (23,311) | (23,311) | (9,643) | (18,755) | (12,376) | (12,508) | (12,769) | |
| Total stockholders' equity | $ (26,519) | (29,040) | (6,639) | (3,905) | (7,160) | (13,018) | (17,574) | (17,574) | (3,905) | (13,018) | (6,639) | (6,769) | (7,031) |
| Change in fair value of warrant liabilities | (2,522) | (2,734) | 3,254 | (391) | 4,556 | (14,774) | (17,296) | 2,864 | (12,740) | 130 | (6,491) | (261) | |
| Total other income (expense) | (2,522) | (2,734) | 3,254 | (391) | 4,556 | (14,774) | (17,296) | 2,864 | (12,740) | 130 | (6,491) | (261) | |
| Income (loss) before income taxes | (2,522) | (2,734) | 3,254 | (391) | 4,556 | (14,774) | (17,296) | 2,864 | (12,740) | 130 | (6,491) | (261) | |
| Net loss | $ (2,522) | $ (2,734) | $ 3,254 | $ (391) | $ 4,556 | $ (14,774) | $ (17,296) | $ 2,864 | $ (12,740) | $ 130 | $ (6,491) | $ (261) | |
| Basic (in dollars per share) | $ (0.08) | $ (0.05) | $ 0.07 | $ (0.01) | $ 0.09 | $ (0.50) | $ (0.60) | $ 0.06 | $ (0.35) | $ 0.00 | $ (0.15) | $ (0.01) | |
| Diluted (in dollars per share) | $ (0.08) | $ (0.04) | $ 0.07 | $ (0.01) | $ 0.08 | $ (0.50) | $ (0.60) | $ 0.06 | $ (0.35) | $ 0.00 | $ (0.15) | $ (0.01) | |
| Increase (decrease) in fair value of warrant liabilities | $ 2,522 | $ 2,734 | $ (3,254) | $ 391 | $ (4,556) | $ 14,774 | $ 17,296 | $ (2,864) | $ 12,740 | $ (130) | $ 6,491 | $ 261 | |
| Net cash provided by operating activities | $ 0 | $ 0 | $ 0 | $ 0 | $ 0 | $ 0 | $ 0 | $ 0 | |||||
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- Definition Amount of nonoperating income including interest expense and gain loss on debt extinguishment. No definition available.
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- Definition Amount of excess of issue price over par or stated value of stock and from other transaction involving stock or stockholder. Includes, but is not limited to, additional paid-in capital (APIC) for common and preferred stock. Reference 1: http://www.xbrl.org/2003/role/exampleRef
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- Definition Fair value, after the effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset, expected to be settled after one year or the normal operating cycle, if longer. Includes assets not subject to a master netting arrangement and not elected to be offset. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition The amount of net income (loss) for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period. Reference 1: http://www.xbrl.org/2003/role/exampleRef
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- Definition Amount of expense (income) related to adjustment to fair value of warrant liability. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition Amount of income (loss) from continuing operations, including income (loss) from equity method investments, before deduction of income tax expense (benefit), and income (loss) attributable to noncontrolling interest. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Sum of the carrying amounts as of the balance sheet date of all liabilities that are recognized. Liabilities are probable future sacrifices of economic benefits arising from present obligations of an entity to transfer assets or provide services to other entities in the future. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition Amount of cash inflow (outflow) from operating activities, including discontinued operations. Operating activity cash flows include transactions, adjustments, and changes in value not defined as investing or financing activities. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition The portion of profit or loss for the period, net of income taxes, which is attributable to the parent. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition The cumulative amount of the reporting entity's undistributed earnings or deficit. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition Total of all stockholders' equity (deficit) items, net of receivables from officers, directors, owners, and affiliates of the entity which are attributable to the parent. The amount of the economic entity's stockholders' equity attributable to the parent excludes the amount of stockholders' equity which is allocable to that ownership interest in subsidiary equity which is not attributable to the parent (noncontrolling interest, minority interest). This excludes temporary equity and is sometimes called permanent equity. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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