Prepaid expenses and other assets (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Prepaid expenses and other assets
CARES Act employee retention credit receivable	$ 821	$ 847
Prepaid subscriptions and service contracts	696	876
Research and development advance payments	271	445
Prepaid insurance	253	158
Other prepaids and current assets	71
Prepaid expenses and other assets	$ 2,112	$ 2,326