Leases - Lease Commitments (Details) - 65 Grove Street, Watertown,MA $ in Thousands	Dec. 31, 2019 USD ($)
Lessee, Lease, Description [Line Items]
2020	$ 1,191
2021	1,811
2022	1,865
2023	1,921
2024	1,979
Thereafter	7,027
Total New Headquarters Lease commitment	$ 15,794

Minimum amount of other commitment not otherwise specified in the taxonomy. Excludes commitments explicitly modeled in the taxonomy, including but not limited to, long-term and short-term purchase commitments, recorded and unrecorded purchase obligations, supply commitments, registration payment arrangements, leases, debt, product warranties, guarantees, environmental remediation obligations, and pensions.

No definition available.

Name:	us-gaap_OtherCommitment
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant