Cover - shares	9 Months Ended
	Sep. 30, 2021	Oct. 28, 2021
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Transition Report	false
Document Period End Date	Sep. 30, 2021
Entity File Number	001-35108
Entity Registrant Name	SERVICESOURCE INTERNATIONAL, INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	81-0578975
Entity Address, Address Line One	707 17th Street, 25th Floor
Entity Address, City or Town	Denver,
Entity Address, State or Province	CO
Entity Address, Postal Zip Code	80202
City Area Code	720
Local Phone Number	889-8500
Title of 12(b) Security	Common Stock, $0.0001 Par Value
Trading Symbol	SREV
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Accelerated Filer
Small Business	true
Emerging Growth Company	false
Entity Shell Company	false
Entity Common stock, shares outstanding		99,067,482
Amendment Flag	false
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q3
Entity Central Index Key	0001310114
Current Fiscal Year End Date	--12-31