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v3.21.1

Fair Value Measurements (Tables) | 3 Months Ended | 12 Months Ended
--- | --- | ---
Mar. 31, 2021 | Dec. 31, 2020
Schedule of change in the fair value of the derivative warrant liabilities | The following table presents the changes in the liability for warrants on convertible preferred stock during the three months ended March 31, 2021 (in thousands): ​
​ | ​ | ​ | ​ | ​
​ |  | Convertible Preferred Warrant Warrant Stock |
Balance as of December 31, 2020 | ​ | $ | 95,342 | ​
Change in fair value of warrants | ​ | ​ | 66,397 | ​
Exercised warrants | ​ | ​ | (253) | ​
Balance as of March 31, 2021 | ​ | $ | 161,486 | ​
Schedule of quantitative information regarding Level 3 fair value measurements inputs as their measurement dates | The key assumptions used for the valuation of the preferred stock warrant liabilities upon remeasurement were as follows: ​
​ | ​ | ​ | ​ | ​ | ​
​ | ​ | Three Months Ended March 31, |
​ |  | 2021 |  | 2020 | ​
Volatility | ​ | 65.0 | % | 75.0 | %
Risk-free interest rate | ​ | 0.1 | % | 0.3 | %
Expected term (in years) | ​ | 1.2 | ​ | 2.3 | ​
Dividend yield | ​ | — | % | — | %
Discount for lack of marketability | ​ | 6.8 | % | 40.0 | %
Star Peak Energy Transition Corp [Member] |  |
Summary of gross holding losses and fair value of held-to-maturity securities | ​
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | Fair Value Measured as of March 31,2021
​ |  | Level 1 |  | Level 2 |  | Level 3 |  | Total
Assets |  | ​ |  |  | ​ |  |  | ​ |  | ​ | ​ | ​
Investments held in Trust Account - U.S. Treasury Securities | ​ | $ | 383,585,733 | ​ | $ | — | ​ | $ | — | ​ | $ | 383,585,733
Liabilities: | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
Warrant liabilities - public warrants | ​ | ​ | 171,878,063 | ​ | ​ | — | ​ | ​ | — | ​ | ​ | 171,878,063
Warrant liabilities - private warrants | ​ | ​ | — | ​ | ​ | — | ​ | ​ | 104,995,656 | ​ | ​ | 104,995,656
Total fair value | ​ | $ | 555,463,796 | ​ | $ | — | ​ | $ | 104,995,656 | ​ | $ | 660,459,452
​
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | Fair Value Measured as of December 31, 2020
​ |  | Level 1 |  | Level 2 |  | Level 3 |  | Total
Assets |  | ​ |  |  | ​ |  |  | ​ |  |  | ​ |
Investments held in Trust Account - U.S. Treasury Securities | ​ | $ | 383,721,747 | ​ | $ | — | ​ | $ | — | ​ | $ | 383,721,747
Liabilities: | ​ |  |  | ​ |  |  | ​ |  |  | ​ |  |
Warrant liabilities - public warrants | ​ |  | 64,339,997 | ​ |  | — | ​ |  | — | ​ |  | 64,339,997
Warrant liabilities - private warrants | ​ |  | — | ​ |  | — | ​ |  | 56,751,981 | ​ |  | 56,751,981
Total fair value | ​ | $ | 448,061,744 | ​ | $ | — | ​ | $ | 56,751,981 | ​ | $ | 504,813,725
Schedule of change in the fair value of the derivative warrant liabilities | ​
​ | ​ | ​ | ​
Warrant liabilities at December 31, 2020 |  | $ | 121,091,978
Change in fair value of warrant liabilities | ​ |  | 155,781,741
Warrant liabilities at March 31, 2021 | ​ | $ | 276,873,719
| The change in the fair value of the derivative warrant liabilities for the year ended December 31, 2020 is summarized as follows: ​
​ | ​ | ​ | ​
Warrant liabilities at January 1, 2020 |  | $ | —
Issuance of Public and Private Warrants | ​ | ​ | 11,822,148
Warrant liabilities at September 30, 2020 | ​ | $ | 11,822,148
Change in fair value of warrant liabilibites | ​ | ​ | 109,269,830
Warrant liabilities at December 31, 2020 | ​ | $ | 121,091,978
Schedule of quantitative information regarding Level 3 fair value measurements inputs as their measurement dates | ​
​ | ​ | ​ | ​ | ​
​ |  | As of March 31, 2021 |
Exercise price | ​ | $ | 11.50 | ​
Stock Price | ​ | $ | 20.58 | ​
Term (in years) | ​ |  | 5.09 | ​
Volatility | ​ |  | 15.00 | %
Risk-free interest rate | ​ |  | 0.94 | %
Dividend yield | ​ |  | — | ​
Probability of completing a Business Combination | ​ |  | 95.00 | %
Discount for lack of marketability | ​ | ​ | 1.5 | %
| ​
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | As of December 31, | ​ | As of August 20, 2020 and | ​
​ |  | 2020 |  | September 30, 2020 | ​
Exercise price | ​ | $ | 11.50 | ​ | $ | 11.50 | ​
Stock price | ​ | $ | 20.46 | ​ | $ | 9.90 | ​
Term (in years) | ​ | ​ | 5.33 | ​ | ​ | 5.58 | ​
Volatility | ​ | ​ | 21.00 | % | ​ | 21.50 | %
Risk-free interest rate | ​ | ​ | 0.41 | % | ​ | 0.34 | %
Dividend yield | ​ | ​ | — | ​ | ​ | — | ​
Probability of completing a Business Combination | ​ | ​ | 85.00 | % | ​ | 50.00 | %
Discount for lack of marketability | ​ | ​ | 3.00 | % | ​ | 4.00 | %

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