Fair Value Measurements - Schedule of fair value on recurring basis (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Liabilities:
Warrant liabilities, noncurrent	$ 15,389	$ 18
5-Year Private Warrants
Liabilities:
Warrant liabilities, noncurrent	15,326	0
Seller Warrants
Liabilities:
Warrant liabilities, noncurrent	63	18
Recurring
Liabilities:
Total	15,389	1,608
Recurring | Level 3
Liabilities:
Accrued compensation for phantom shares	0	1,590
Recurring | Level 2 | 5-Year Private Warrants
Liabilities:
Warrant liabilities, noncurrent	15,327
Recurring | Level 2 | Seller Warrants
Liabilities:
Warrant liabilities, noncurrent	$ 62	$ 18