Cover Page - USD ($)	12 Months Ended
	Dec. 31, 2021	Feb. 28, 2022	Jun. 30, 2021
Cover [Abstract]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2021
Current Fiscal Year End Date	--12-31
Document Transition Report	false
Entity File Number	001-38501
Entity Registrant Name	BLACK DIAMOND THERAPEUTICS, INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	81-4254660
Entity Address, Address Line One	One Main Street, 10th Floor
Entity Address, City or Town	Cambridge
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	02142
City Area Code	(617)
Local Phone Number	252-0848
Title of 12(b) Security	Common stock, par value $0.0001
Trading Symbol	BDTX
Security Exchange Name	NASDAQ
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
ICFR Auditor Attestation Flag	false
Entity Shell Company	false
Entity Public Float			$ 340,487,618
Entity Common Stock, Shares Outstanding		36,271,465
Documents Incorporated by Reference	Part III of this Annual Report on Form 10-K incorporates by reference certain information from the definitive Proxy Statement for the registrant’s 2022 Annual Meeting of Stockholders, or the Proxy Statement, which the registrant intends to file pursuant to Regulation 14A with the Securities and Exchange Commission not later than 120 days after the registrant’s fiscal year ended December 31, 2021. Except with respect to information specifically incorporated by reference, the Proxy Statement is not deemed to be filed as part of this Annual Report on Form 10-K.
Amendment Flag	false
Document Fiscal Period Focus	FY
Document Fiscal Year Focus	2021
Entity Central Index Key	0001701541