Fair Value of Financial Instruments - Schedule of Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) - Fair Value Measurements Recurring Basis - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Warrants
Liabilities:
Liabilities	$ 4,225	$ 1,914
Forward Obligation
Liabilities:
Liabilities	3,300	2,750
Contingent Earnout
Liabilities:
Liabilities	275	930
Significant Unobservable Inputs (Level 3) | Warrants
Liabilities:
Liabilities	4,225	1,914
Significant Unobservable Inputs (Level 3) | Forward Obligation
Liabilities:
Liabilities	3,300	2,750
Significant Unobservable Inputs (Level 3) | Contingent Earnout
Liabilities:
Liabilities	275	930
Money Market Funds
Assets:
Assets	13,103	50,897
Money Market Funds | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Assets	$ 13,103	$ 50,897