Income taxes - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Operating Loss Carryforwards [Line Items]
Deferred tax asset valuation allowance	$ 56,706,000	$ 33,351,000
Change in Valuation Allowance	23,400,000
state net operating loss carryforwards	$ 200
Tax credit limitation on use	The federal and state net operating losses can be carried forward indefinitely, subject to an 80% limitation against taxable income.
Tax Credit Carryforward, Amount	$ 3,700,000
Orphan Drug Credit	$ 2,300,000
Use of annual operating loss carryforwards	Sections 382 and 383, annual use of the Company’s net operating loss carryforwards may be limited in the event a cumulative change in ownership of more than 50% occurs within a three-year period.
CARES Act NOL carryover/carryback offset to taxable income.	50.00%
Unrecognized tax benefits	$ 1,968,000	$ 1,011,000	$ 210,000
PPP Loan
Operating Loss Carryforwards [Line Items]
Proceeds from loans	$ 700,000
Domestic Tax Authority
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards Expiration Period	2040
orphan drug credit carryforwards Expiration Period	2041
Domestic Tax Authority | Research and Development Tax Credit
Operating Loss Carryforwards [Line Items]
Federal net operating loss carryforward	$ 83,000,000.0
California Franchise Tax Board | Research and Development Tax Credit
Operating Loss Carryforwards [Line Items]
Tax Credit Carryforward, Amount	$ 2,000,000.0