Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2026	Dec. 31, 2025	Dec. 31, 2024
Current assets:
Cash and cash equivalents	$ 48,466	$ 197,533	$ 58,212
Marketable securities	270,374	154,773	182,809
Unbilled accounts receivable		0	2,096
Prepaid expenses and other current assets	4,011	5,174	6,806
Total current assets	322,851	357,480	249,923
Property and equipment, net	0	2,824	3,900
Operating lease right-of-use assets	0	4,241	5,684
Restricted cash	1,092	1,201	1,201
Other assets	9	538	10
Total assets	323,952	366,284	260,718
Current liabilities:
Accounts payable	3,425	1,592	1,164
Accrued expenses and other current liabilities	4,355	9,052	7,694
Operating lease liability, current	2,518	2,404	2,186
Total current liabilities	10,298	13,048	11,044
Operating lease liability, excluding current portion	2,760	4,039	6,443
Other liabilities, excluding current portion	197	197	197
Total liabilities	13,255	17,284	17,684
Commitments and contingencies (Note 12)
Stockholders' equity:
Preferred stock, $0.001 par value; 5,000,000 shares authorized; no shares issued or outstanding	0	0	0
Common stock, $0.001 par value; 200,000,000 shares authorized; 76,285,157 and 66,578,891 shares issued and outstanding as of June 30, 2026 and December 31, 2025, respectively	76	67	54
Additional paid-in capital	950,536	943,037	762,248
Accumulated other comprehensive gain	(567)	174	130
Accumulated deficit	(639,348)	(594,278)	(519,398)
Total stockholders' equity	310,697	349,000	243,034
Total liabilities and stockholders' equity	$ 323,952	$ 366,284	$ 260,718

Accrued liabilities and other current liabilities.

No definition available.

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Namespace Prefix:	fulc_
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).