Fair Value of Financial Assets and Liabilities - Measured on a Recurring Basis (Details) - Fair Value, Recurring - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Cash equivalents—money market funds	$ 47,793	$ 44,834
Fair value of derivative liability	821
Embedded derivative liability		455
Embedded derivative liability
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Embedded derivative liability		455
Level 1
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Cash equivalents—money market funds	20,000	16,816
Fair value of derivative liability	0
Embedded derivative liability		0
Level 1 | Embedded derivative liability
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Embedded derivative liability		0
Level 2
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Cash equivalents—money market funds	27,793	28,018
Fair value of derivative liability	0
Embedded derivative liability		0
Level 2 | Embedded derivative liability
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Embedded derivative liability		0
Level 3
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Cash equivalents—money market funds	0	0
Fair value of derivative liability	$ 821
Embedded derivative liability		455
Level 3 | Embedded derivative liability
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Embedded derivative liability		$ 455