Condensed Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended		12 Months Ended
Condensed Statements of Cash Flows - USD ($) $ in Thousands	Sep. 30, 2025	Sep. 30, 2024	Dec. 31, 2024
Cash flows from operating activities
Net loss	$ (159,506)	$ (111,197)
Adjustments to reconcile net loss to net cash used in operating activities
Stock-based compensation expense	16,463	18,538
Vesting of common stock warrants in return for services		66
Change in fair value of derivative liability	(65)	27
Depreciation and amortization	3,478	3,557
Amortization of right-of-use assets	2,167	1,364
Net accretion of discount on marketable securities	(3,587)	(5,332)
Changes in operating assets and liabilities
Prepaid expenses and other current assets	2,741	(508)
Other assets	(5,119)	(2,181)
Accounts payable	2,477	(591)
Accrued and other liabilities	5,780	8,890
Deferred revenue	(119)	69
Operating lease liabilities	(2,343)	(1,424)
Net cash used in operating activities	(137,633)	(88,722)
Cash flows from investing activities
Purchase of marketable securities	(264,721)	(409,874)
Maturities of marketable securities	301,201	103,215
Acquisition of property and equipment	(606)	(2,837)
Net cash provided by (used in) investing activities	35,874	(309,496)
Cash flows from financing activities
Issuance of common stock upon exercise of stock options and warrants	118	4,530
Issuance of common stock - 2020 ESPP	860	707
Net cash provided by financing activities	978	336,649
Net decrease in cash and cash equivalents	(100,781)	(61,569)
Cash and cash equivalents, beginning of period	149,336	249,108	$ 249,108
Cash and cash equivalents, end of period	$ 48,555	187,539	$ 149,336
Supplemental disclosures of noncash investing and financing information
Purchases of property and equipment in accounts payable and accrued and other liabilities		694
Right-of-Use Asset Obtained in Exchange for Operating Lease Liability		11,587
Public offering
Cash flows from financing activities
Issuance of common stock under the offering program, net of issuance costs		316,149
ATM Offering Program
Cash flows from financing activities
Issuance of common stock under the offering program, net of issuance costs		$ 15,263

4D Molecular Therapeutics, Inc. 10-Q