Fair Value Measurements - Fair Value Methodology (Details)
$ in Thousands
Dec. 31, 2020
USD ($)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]  
Principal Amount $ 3,612
2019 Convertible Promissory Notes  
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]  
Principal Amount 3,000
Fair Value $ 3,612