Quarterly report pursuant to Section 13 or 15(d)

Fair Value Measurements - Change in Level 3 (Details)

v3.21.2
Fair Value Measurements - Change in Level 3 (Details) - USD ($)
$ in Thousands
3 Months Ended 9 Months Ended
Sep. 30, 2021
Sep. 30, 2020
Sep. 30, 2021
Sep. 30, 2020
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]        
Gain on revaluation of warrants issued in connection with the February 2021, June 2020, December 2019 and May 2019 financings $ (1,125) $ (4,476) $ (2,011) $ 1,579
Warrant Liability        
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]        
Beginning balance     6,037  
Initial fair value of warrants in connection with 2021 financing     1,936  
Gain on revaluation of warrants issued in connection with the February 2021, June 2020, December 2019 and May 2019 financings     (2,011)  
Reclassification of warrant liability to equity upon exercise of warrants     (2,461)  
Ending balance $ 3,501   $ 3,501