Stockholders' equity (deficit) - Common stock reserved for future issuance (Details) - shares |
Sep. 30, 2021 |
Dec. 31, 2020 |
|---|---|---|
| Equity [Abstract] | ||
| Conversion of Series F Preferred Stock (in shares) | 0 | 7,251,189 |
| Exercise of options to purchase common stock (in shares) | 2,672,937 | 1,302,574 |
| Exercise of warrants to purchase common stock (in shares) | 9,433,584 | 9,916,997 |
| Conversion of notes payable (in shares) | 0 | 1,255,039 |
| Total (in shares) | 12,106,521 | 19,725,799 |
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- Definition Number of shares of convertible preferred stock issuable upon conversion. No definition available.
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- Definition Number of share options (or share units) exercised during the current period. No definition available.
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- Definition Number of shares of notes payable issuable upon conversion. No definition available.
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- Definition Warrants reserved to purchases shares of common stock. No definition available.
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- Definition Aggregate number of common shares reserved for future issuance. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- References No definition available.
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