Commitments and Contingencies - Operating Leases - (Details) - USD ($) $ in Thousands				1 Months Ended	3 Months Ended
	May 14, 2021	Feb. 01, 2021	Feb. 01, 2020	May 31, 2019	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Commitments and Contingencies
Right-of-use assets and other					$ 99		$ 105
Lease asset liability					64
Operating lease, liability current					27		26
Operating lease, liability noncurrent					$ 37		45
Korea
Commitments and Contingencies
Term of contract				5 years
Option to renew				true
Renewal term				5 years
Operating lease discount rate					10.00%
Weighted average remaining lease term					2 years 3 months
Non-cash expense related to Korea lease					$ 6	$ 5
Operating lease cash payments					8	8
Head Quarters in Boston Lease
Commitments and Contingencies
Term of contract	6 months	6 months	1 year
Monthly rental cost	$ 3	$ 3	$ 21		1
Rent concessions granted by the landlord	$ 2	$ 1	$ 32
Lease expense					4	$ 35
Right-of-use assets and other					0		0
Lease asset liability					$ 0		$ 0