Summary of significant accounting policies - Additional Information (Details) - USD ($)	1 Months Ended	3 Months Ended			6 Months Ended
	Mar. 31, 2023	Jun. 30, 2023	Mar. 31, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022
Lessee, Lease, Description [Line Items]
Impairment of property and equipment	$ 3,400,000	$ 0	$ 3,400,000	$ 0	$ 3,418,000	$ 0
U.S. treasury securities		81,545,000			81,545,000		$ 95,737,000
Allowance for credit loss		0			0
Unrealized loss		$ 31,100,000			$ 31,100,000
Expected dividends		0.00%		0.00%	0.00%	0.00%
Prefunded Warrants
Lessee, Lease, Description [Line Items]
Outstanding pre-funded warrants (in shares)		11,483,010		12,663,010	11,483,010	12,663,010
Money market funds
Lessee, Lease, Description [Line Items]
Money market funds		$ 30,593,000			$ 30,593,000		$ 33,767,000
Maximum
Lessee, Lease, Description [Line Items]
Property and equipment, useful life		7 years			7 years
Maximum | Office space
Lessee, Lease, Description [Line Items]
Lease term		12 months			12 months
Minimum [Member]
Lessee, Lease, Description [Line Items]
Property and equipment, useful life		3 years			3 years