Organization and summary of significant accounting policies - Additional Information (Details)	1 Months Ended	12 Months Ended
	Jan. 31, 2023 USD ($)	Dec. 31, 2023 USD ($) shares	Dec. 31, 2022 USD ($) NumberOfSegment shares
Organization And Summary Of Significant Accounting Policies [Line Items]
Entity Incorporation, State or Country Code		DE
Company formation date		2007-03
Common Stock, Shares, Issued | shares		48,077,599	46,336,166
Preferred Stock, Shares Issued | shares		0	0
Accumulated deficit		$ (416,263,000)	$ (292,801,000)
Maximum aggregate gross sale proceeds		$ 0	$ 61,682,000
Uncertain tax positions percentage		50.00%
Number of operating segment | NumberOfSegment			1
Impairment losses		$ 0	$ 0
Cash and cash equivalents		50,400,000	0
Operating lease right-of-use-assets		1,495,000	2,423,000
Operating lease liabilities		1,624,000	1,521,000
Operating lease liabilities, less current portion		836,000	2,460,000
Accrued clinical trial cost		$ 12,500,000
Accumulated deficit
Organization And Summary Of Significant Accounting Policies [Line Items]
Accumulated deficit			$ 416,300,000
Maximum aggregate gross sale proceeds	$ 100,000,000
Class B Common Stock
Organization And Summary Of Significant Accounting Policies [Line Items]
Common Stock, Shares, Issued | shares		0	1,211,959