Consolidated Statements of Stockholders' Equity (Deficit) - USD ($) $ in Thousands |
Restricted Stock Units (RSUs) [Member]
Common Stock [Member]
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Restricted Stock Units (RSUs) [Member]
Additional Paid-in Capital [Member]
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Restricted Stock Units (RSUs) [Member]
Retained Earnings [Member]
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Restricted Stock Units (RSUs) [Member] |
January 2019 Public Offering [Member]
Common Stock [Member]
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January 2019 Public Offering [Member]
Additional Paid-in Capital [Member]
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January 2019 Public Offering [Member]
Retained Earnings [Member]
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January 2019 Public Offering [Member] |
May 2019 Public Offering [Member]
Common Stock [Member]
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May 2019 Public Offering [Member]
Additional Paid-in Capital [Member]
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May 2019 Public Offering [Member]
Retained Earnings [Member]
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May 2019 Public Offering [Member] |
ATM [Member]
Common Stock [Member]
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ATM [Member]
Additional Paid-in Capital [Member]
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ATM [Member]
Retained Earnings [Member]
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ATM [Member] |
Common Stock [Member] |
Additional Paid-in Capital [Member] |
Retained Earnings [Member] |
Total |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Balance (in shares) at Dec. 31, 2018 | 38,932,437 | |||||||||||||||||||
| Balance at Dec. 31, 2018 | $ 39 | $ 145,147 | $ (95,096) | $ 50,090 | ||||||||||||||||
| Stock-based compensation | 0 | 4,206 | 0 | 4,206 | ||||||||||||||||
| Warrants issued related to Veolia agreement | $ 0 | 5,780 | 0 | $ 5,780 | ||||||||||||||||
| Common stock issued upon RSU vesting (in shares) | 854,064 | 533,655 | ||||||||||||||||||
| Common stock issued upon RSU vesting | $ 1 | $ 0 | $ 0 | $ 1 | ||||||||||||||||
| Common stock issued for consulting services (in shares) | 2,036,279 | |||||||||||||||||||
| Common stock issued for consulting services | $ 2 | 4,925 | 0 | $ 4,927 | ||||||||||||||||
| Common stock issued, net of transaction costs (in shares) | 5,175,000 | 11,000,000 | ||||||||||||||||||
| Common stock issued, net of transaction costs | $ 5 | $ 9,058 | $ 0 | $ 9,063 | $ 11 | $ 20,306 | $ 0 | $ 20,317 | ||||||||||||
| Net loss | $ 0 | 0 | (44,795) | (44,795) | ||||||||||||||||
| Balance (in shares) at Dec. 31, 2019 | 57,997,780 | |||||||||||||||||||
| Balance at Dec. 31, 2019 | $ 58 | 189,422 | (139,891) | 49,589 | ||||||||||||||||
| Stock-based compensation | $ 0 | 3,569 | 0 | $ 3,569 | ||||||||||||||||
| Common stock issued upon RSU vesting (in shares) | 3,178,337 | 691,820 | ||||||||||||||||||
| Common stock issued upon RSU vesting | $ 3 | $ 0 | $ 0 | $ 3 | ||||||||||||||||
| Common stock issued for consulting services (in shares) | 67,522 | |||||||||||||||||||
| Common stock issued for consulting services | $ 0 | 64 | 0 | $ 64 | ||||||||||||||||
| Common stock issued, net of transaction costs (in shares) | 3,217,426,000 | 3,217,426 | ||||||||||||||||||
| Common stock issued, net of transaction costs | $ 3 | $ 3,673 | $ 0 | $ 3,676 | ||||||||||||||||
| Net loss | $ 0 | 0 | (25,762) | (25,762) | ||||||||||||||||
| Balance (in shares) at Dec. 31, 2020 | 64,461,065 | |||||||||||||||||||
| Balance at Dec. 31, 2020 | $ 64 | $ 196,728 | $ (165,653) | $ 31,139 |
| X | ||||||||||
- Definition Amount of increase to additional paid-in capital (APIC) for recognition of cost for option under share-based payment arrangement. No definition available.
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| X | ||||||||||
- Definition Amount of increase in additional paid in capital (APIC) resulting from the issuance of warrants. Includes allocation of proceeds of debt securities issued with detachable stock purchase warrants. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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| X | ||||||||||
- Definition The portion of profit or loss for the period, net of income taxes, which is attributable to the parent. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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| X | ||||||||||
- Definition Number of shares issued which are neither cancelled nor held in the treasury. No definition available.
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| X | ||||||||||
- Definition Number of shares issued in lieu of cash for services contributed to the entity. Number of shares includes, but is not limited to, shares issued for services contributed by vendors and founders. No definition available.
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| X | ||||||||||
- Definition Number of new stock issued during the period. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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| X | ||||||||||
- Definition Number of shares issued during the period related to Restricted Stock Awards, net of any shares forfeited. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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| X | ||||||||||
- Definition Value of stock issued in lieu of cash for services contributed to the entity. Value of the stock issued includes, but is not limited to, services contributed by vendors and founders. No definition available.
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| X | ||||||||||
- Definition Equity impact of the value of new stock issued during the period. Includes shares issued in an initial public offering or a secondary public offering. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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| X | ||||||||||
- Definition Value of stock related to Restricted Stock Awards issued during the period, net of the stock value of such awards forfeited. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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| X | ||||||||||
- 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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