Agreements with Incyte Corporation - Deferred revenue liabilities (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2019 USD ($)
Contract With Customer Liability [Abstract]
Deferred revenue, Balance at Beginning of Period	$ 10,202
Deferred revenue, Additions	0
Deferred revenue, Deductions	1,474
Deferred revenue, Balance at End of Period	$ 8,728