Commitments and Contingencies (Details) $ in Thousands		3 Months Ended		5 Months Ended	6 Months Ended
	Jan. 15, 2019 USD ($)	Jun. 30, 2020 USD ($)	Jun. 30, 2019 USD ($)	Feb. 28, 2019 agreement	Jun. 30, 2020 USD ($)	Jun. 30, 2019 USD ($)	Dec. 31, 2019 USD ($)
Lessee, Lease, Description [Line Items]
Sublease income		$ 87	$ 85		$ 200	$ 200
Number of non-cancelable operating lease | agreement				2
Right-of-use assets		2,616			2,616		$ 3,331
Operating Lease, Liability		$ 3,107			$ 3,107
Operating lease discount rate		7.00%			7.00%
Noncancelable operating leases term		3 years 5 months 1 day			3 years 5 months 1 day
Operating lease expense		$ 200	100		$ 500	200
Cash paid for amount included in lease liabilities		$ 500	$ 400		1,000	$ 500
Waltham Massachusetts
Lessee, Lease, Description [Line Items]
Sublease income	$ 600				$ 100
Minimum
Lessee, Lease, Description [Line Items]
Operating lease term		3 months			3 months
Operating lease renewal term		5 years			5 years
Maximum
Lessee, Lease, Description [Line Items]
Operating lease term		4 years			4 years
Operating lease renewal term		10 years			10 years