Prepaid expenses and other current assets - Narrative (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Prepaid Expenses and Other Current Assets [Line Items]
Pre-contract costs	$ 868	$ 546
Prepaid Expenses and Other Current Assets
Prepaid Expenses and Other Current Assets [Line Items]
Pre-contract costs	$ 868	$ 546