Significant risks and uncertainties including business and credit concentrations (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2021 USD ($) customer	Dec. 31, 2020 USD ($) customer
Concentration Risk [Line Items]
Allowance for doubtful accounts | $	$ 45	$ 103
Revenue from Contract with Customer Benchmark | Customers
Concentration Risk [Line Items]
Number of customers with concentration risk	0	0
Accounts Receivable. | Customers
Concentration Risk [Line Items]
Number of customers with concentration risk	0	0