Accrued Expenses (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Accrued Expenses
Employee related expenses	$ 4,179	$ 4,971
Process and platform development expenses	2,266	735
Intellectual property and patent related fees	1,598	3,725
Sublicensing expenses	813	11,416
Professional service expenses	609	674
Other expenses	729	599
Total	$ 10,194	$ 22,120