Restructuring Costs - Accrual Activity for Restructuring Accrual (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2019 USD ($)
Restructuring Reserve [Roll Forward]
Beginning balance	$ 0
Accruals	5,781
Revised estimates	(336)
Payments	(5,125)
Ending balance	320
Employee Termination Benefits
Restructuring Reserve [Roll Forward]
Beginning balance	0
Accruals	3,335
Revised estimates	11
Payments	(3,163)
Ending balance	183
Clinical Trial Close-out Costs
Restructuring Reserve [Roll Forward]
Beginning balance	0
Accruals	2,131
Revised estimates	(621)
Payments	(1,483)
Ending balance	27
Other Development Costs
Restructuring Reserve [Roll Forward]
Beginning balance	0
Accruals	315
Revised estimates	24
Payments	(229)
Ending balance	110
Fixed Asset Disposals
Restructuring Reserve [Roll Forward]
Beginning balance	0
Accruals	0
Revised estimates	250
Payments	(250)
Ending balance	$ 0