Leases (Details) $ in Thousands		6 Months Ended
	Apr. 01, 2019 USD ($) ft² item	Jun. 30, 2020 USD ($) lease	Jan. 01, 2020 USD ($)
Operating Lease, Right-of-Use Asset		$ 12,120
Operating Lease, Liability, Noncurrent		22,458
Lease for facilities in Billerica, Massachusetts
Term of operating lease	137 months
Square footage of office and laboratory space | ft²	92,000
Drawing capacity	$ 1,000
Landlord Contribution Towards Tenant Improvements	$ 8,200
Lease Agreement Number Of Options To Extend | item	2
Lease Agreement Lease Extension Term	5 years
Operating Lease, Right-of-Use Asset			$ 12,200
Operating Lease, Liability, Noncurrent			22,800
Deferred rent expense		3,000
Lease Obligation Incentive		$ 7,600
Tristeyagen Umea Lease [Member]
Number of leases | lease		3
Tristeyagen Umea Lease [Member] | Maximum
Operating Lease, Right-of-Use Asset			100
Operating Lease, Liability, Noncurrent			$ 100