Condensed Consolidated Balance Sheets (unaudited) - USD ($) $ in Thousands	Sep. 30, 2026	Dec. 31, 2025
Current assets:
Cash and cash equivalents	$ 180,379	$ 78,558
Marketable securities	249,593	138,106
Accounts receivable (includes $8,000 accounts receivable from a related party as of September 30, 2026)	8,821	1,307
Inventory	1,885	0
Prepaid expenses and other current assets	20,307	8,520
Total current assets	460,985	226,491
Property and equipment, net	154,537	155,776
Operating lease right-of-use assets, net	95,171	97,055
Intangible assets, net	2,486	3,300
Goodwill	10,513	10,513
Other long-term assets	279	4,800
Restricted cash	9,560	9,118
Total assets	733,531	507,053
Current liabilities:
Accounts payable	8,279	6,084
Accrued compensation and other related benefits	12,466	13,424
Accrued expenses and other current liabilities (includes $1,200 due to a related party as of September 30, 2026)	3,689	3,783
Deferred revenue, current	0	7,123
Current portion of lease liabilities	11,765	10,114
Total current liabilities	36,199	40,528
Long-term liabilities:
Lease liabilities, net of current portion	189,894	199,015
Deferred revenue, non-current, related party (includes $24,594 due to a related party as of September 30, 2026)	24,594	49,138
Other long-term liabilities (includes $1,140 due to a related party as of September 30, 2026)	1,515	15,433
Total liabilities	252,202	406,609
Commitments and contingencies (Note 13)
Stockholders’ Equity:
Preferred stock, $0.0001 par value – 10,000,000 shares authorized; no shares issued and outstanding as of September 30, 2026 and December 31, 2025	0	0
Common stock, $0.0001 par value – 1,000,000,000 shares authorized; 110,870,300 and 67,944,192 shares issued and outstanding as of September 30, 2026, and December 31, 2025, respectively.	11	7
Additional paid-in capital	1,901,263	1,447,410
Accumulated other comprehensive income (loss)	(362)	132
Accumulated deficit	(1,419,583)	(1,347,105)
Total stockholders’ equity	481,329	100,444
Total liabilities and stockholders’ equity	733,531	507,053
Nonrelated Party
Long-term liabilities:
Convertible note	0	41,600
Related Party
Current assets:
Accounts receivable (includes $8,000 accounts receivable from a related party as of September 30, 2026)	8,000
Current liabilities:
Accrued expenses and other current liabilities (includes $1,200 due to a related party as of September 30, 2026)	1,200
Long-term liabilities:
Convertible note	0	$ 60,895
Deferred revenue, non-current, related party (includes $24,594 due to a related party as of September 30, 2026)	24,594
Other long-term liabilities (includes $1,140 due to a related party as of September 30, 2026)	$ 1,140

Accrued and Other Liabilities, Current

No definition available.

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Namespace Prefix:	frnm_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Carrying value as of the balance sheet date of liabilities incurred (and for which invoices have typically been received) and payable to vendors for goods and services received that are used in an entity's business. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).