Loan and Security Agreements - Additional Information (Details) - USD ($)			3 Months Ended		9 Months Ended
	Dec. 20, 2024	Nov. 20, 2024	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024	Sep. 09, 2022
Debt Instrument [Line Items]
Debt instrument drew			$ 32,500,000		$ 32,500,000
Debt Instrument, Payment Terms					The term loans will mature on September 1, 2029, and will be subject to monthly interest only payments until September 30, 2027, provided the Company achieves certain financial and clinical milestones, following which the term loans will amortize in equal monthly installments until maturity. If the Company does not achieve such financial and clinical milestones by June 30, 2026, the maturity date will be September 1, 2028, and the interest only period will end on September 30, 2026, following which the term loans will amortize in equal monthly installments until maturity.
K2HV [Member]
Debt Instrument [Line Items]
Principal amount							$ 60,000,000
Convertible outstanding principal balance		$ 15,000,000
Converted instrument, shares issued		3,134,796
Conversion price		$ 4.785
Repaid remaining principal amount	$ 15,000,000
Exit fee	1,800,000
Prepayment fee	300,000
Rcognized loss from extinguishment	(1,100,000)
Interest expense				$ 1,000,000		$ 2,900,000
Silicon Valley Bank [Member]
Debt Instrument [Line Items]
Principal amount	$ 52,500,000
Term loan maturity date	Sep. 01, 2029
Contractual interest rate	7.00%
Prime rate	0.75%
Interest rate					8.46%
Final fee	5.00%
Percentage of loan prepayment fee in first year	3.00%
Percentage of loan prepayment fee in year two	2.00%
Percentage of loan prepayment fee in there after year two	1.00%
Interest expense			$ 700,000		$ 2,100,000
Tranche One [Member] \| K2HV [Member]
Debt Instrument [Line Items]
Debt instrument drew							$ 30,000,000
Tranche One [Member] \| Silicon Valley Bank [Member]
Debt Instrument [Line Items]
Debt instrument drew	$ 32,500,000
Tranche Two [Member] \| Silicon Valley Bank [Member]
Debt Instrument [Line Items]
Debt instrument remaining borrowing capacity	$ 20,000,000
Maximum [Member] \| Silicon Valley Bank [Member]
Debt Instrument [Line Items]
Contractual interest rate	9.75%

TScan Therapeutics, Inc. 10-Q