Term Notes - Schedule of Future Minimum and Estimated Payments (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Dec. 31, 2020
Debt Disclosure [Abstract]
2021 (remainder)	$ 146
2022	6,045
2023	12,779
Total future payments	18,970
Less amounts representing interest	(902)
Less final payment	(1,568)
Total principal amount of term note payments	$ 16,500	$ 16,500