Document and Entity Information - USD ($)

12 Months Ended

Dec. 31, 2021

Feb. 24, 2022

Jun. 30, 2021

Cover [Abstract]

Document Type

10-K

Amendment Flag

false

Document Period End Date

Dec. 31, 2021

Document Fiscal Year Focus

2021

Document Fiscal Period Focus

FY

Title of 12(b) Security

Common stock, par value $0.001 per share

Trading Symbol

FULC

Security Exchange Name

NASDAQ

Entity Registrant Name

FULCRUM THERAPEUTICS, INC.

Entity Central Index Key

0001680581

Entity Current Reporting Status

Yes

Entity Interactive Data Current

Yes

Current Fiscal Year End Date

--12-31

Entity Filer Category

Non-accelerated Filer

Entity Common Stock, Shares Outstanding

40,637,216

Entity Shell Company

false

Entity Small Business

true

Entity Emerging Growth Company

true

Entity Ex Transition Period

false

Entity File Number

001-38978

Entity Incorporation, State or Country Code

DE

Entity Tax Identification Number

47-4839948

Entity Address, Address Line One

26 Landsdowne Street

Entity Address, City or Town

Cambridge

Entity Address, State or Province

MA

Entity Address, Postal Zip Code

02139

City Area Code

617

Local Phone Number

651-8851

Document Transition Report

false

ICFR Auditor Attestation Flag

false

Document Annual Report

true

Entity Voluntary Filers

No

Entity Well-known Seasoned Issuer

No

Entity Public Float

$ 248,910,889

Documents Incorporated by Reference

DOCUMENTS INCORPORATED BY REFERENCE

The registrant intends to file a definitive proxy statement pursuant to Regulation 14A relating to the 2022 Annual Meeting of Stockholders within 120 days of the end of the registrant’s fiscal year ended December 31, 2021. Portions of such definitive proxy statement are incorporated by reference into Part III of this Annual Report on Form 10-K to the extent stated herein.

Auditor Name

Ernst & Young LLP

Auditor Firm ID

42

Auditor Location

Boston, Massachusetts