Summary of significant accounting policies - Risk of Concentrations of Credit, Significant Customers and Significant Suppliers (Details) - Customers	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2021
Total revenue | Major Customers
Concentration Risk [Line Items]
Customer concentration risk percentage	57.30%	15.90%	21.70%	13.70%
Total revenue | Customer A
Concentration Risk [Line Items]
Customer concentration risk percentage	28.30%		21.70%
Total revenue | Customer B
Concentration Risk [Line Items]
Customer concentration risk percentage	15.00%
Total revenue | Customer C
Concentration Risk [Line Items]
Customer concentration risk percentage	14.00%
Total revenue | Customer D
Concentration Risk [Line Items]
Customer concentration risk percentage				13.70%
Total revenue | Customer E
Concentration Risk [Line Items]
Customer concentration risk percentage		15.90%
Accounts receivable | Major Customers
Concentration Risk [Line Items]
Customer concentration risk percentage			63.10%		52.70%
Accounts receivable | Customer A
Concentration Risk [Line Items]
Customer concentration risk percentage			20.40%		19.50%
Accounts receivable | Customer B
Concentration Risk [Line Items]
Customer concentration risk percentage			15.90%		12.60%
Accounts receivable | Customer C
Concentration Risk [Line Items]
Customer concentration risk percentage			14.10%
Accounts receivable | Customer F
Concentration Risk [Line Items]
Customer concentration risk percentage			12.70%
Accounts receivable | Customer G
Concentration Risk [Line Items]
Customer concentration risk percentage					10.60%
Accounts receivable | Customer H
Concentration Risk [Line Items]
Customer concentration risk percentage					10.00%