Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2022	Aug. 11, 2022
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2022
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	Q2
Trading Symbol	CALA
Entity Registrant Name	CALITHERA BIOSCIENCES, INC.
Entity Central Index Key	0001496671
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Common Stock, Shares Outstanding		4,865,134
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Shell Company	false
Entity File Number	001-36644
Entity Tax Identification Number	27-2366329
Entity Address, Address Line One	343 Oyster Point Blvd.
Entity Address, Address Line Two	Suite 200
Entity Address, City or Town	South San Francisco
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	94080
City Area Code	650
Local Phone Number	870-1000
Document Quarterly Report	true
Document Transition Report	false
Entity Incorporation, State or Country Code	DE
Title of 12(b) Security	Common Stock, 0.0001 par value
Security Exchange Name	NASDAQ