Collaboration and Licensing Agreements - Deferred Revenue (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021
Deferred revenue - non-current
Beginning balance	$ 4,727
Ending balance	12,421
2019 KKC Agreement
Deferred revenue - current
Beginning balance	0	$ 4,177
Decreases due to revenue recognized in the period for which cash has been received	0	(2,765)
Ending balance	0	1,412
2017 KKC Agreement
Deferred revenue - non-current
Beginning balance	4,727	0
Increases due to cash received during the period	3,829	2,947
Increases to amounts invoiced, for which cash has not yet been received	3,865	0
Ending balance	$ 12,421	$ 2,947