Government assistance programs (Details) - USD ($)	1 Months Ended		12 Months Ended
	Jan. 31, 2023	Jul. 31, 2020	Dec. 31, 2023	Dec. 31, 2022	May 31, 2021
Unusual or Infrequent Item, or Both [Line Items]
Employee retention credit receivable				$ 847,000
Other Transaction Authority for Prototype Agreement
Unusual or Infrequent Item, or Both [Line Items]
Grants Receivable		$ 13,300,000			$ 17,600,000
Expenses relating to extension of an agreement	$ 0
Payment period of reimbursement contract		30 days
Contra-research and development expense			$ 0	600,000
Reimbursement expenses received				$ 17,600,000