Shanghai Adicet Biotechnology Co., Ltd. (the Adicet VIE) - carrying amount of assets and liabilities of the Adicet VIE excluding intercompany balances (Details) - USD ($) $ in Thousands	Mar. 31, 2025	Dec. 31, 2024	Mar. 31, 2024
Variable Interest Entity [Line Items]
Cash and cash equivalents	$ 28,133	$ 56,495	$ 159,711
Prepaid expenses and other current assets	3,124	3,833
Total current assets	153,563	180,136
Property and equipment, net	21,108	22,524
Total assets	191,271	220,219
Accrued and other current liabilities	9,061	11,430
Total liabilities	29,825	33,610
Adicet VIE [Member]
Variable Interest Entity [Line Items]
Cash and cash equivalents	150	46
Prepaid expenses and other current assets	15	28
Total current assets	165	74
Property and equipment, net	10	4
Total assets	175	78
Accrued and other current liabilities	20	9
Total liabilities	$ 20	$ 9