Indebtedness - Debt (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Indebtedness
Debt, Current	$ 66	$ 57
Debt, Non current	160	221
NEBT Loan
Indebtedness
Debt, Current	8	13
Debt, Non current	32	31
RETOS 2015 Loan
Indebtedness
Debt, Current	58	44
Debt, Non current	$ 128	$ 190

Amount, excluding unamortized premium (discount) and debt issuance cost, of long-term debt. Excludes lease obligation.

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