Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2017	Oct. 31, 2017
Document And Entity Information [Abstract]
Document Type	10-Q/A
Amendment Flag	true
Document Period End Date	Sep. 30, 2017
Document Fiscal Year Focus	2017
Document Fiscal Period Focus	Q3
Trading Symbol	SMSI
Entity Registrant Name	SMITH MICRO SOFTWARE INC
Entity Central Index Key	0000948708
Current Fiscal Year End Date	--12-31
Entity Filer Category	Smaller Reporting Company
Entity Common Stock, Shares Outstanding		14,283,953
Amendment Description	Smith Micro Software, Inc. (the “Company”) is filing this Amendment No. 1 on Form 10-Q/A (this “Amendment”) solely to add disclosure in Note 19 to the financial statements related to the impact of the Company’s early adoption for the quarterly periods ended March 31, 2017 and June 30, 2017 of Accounting Standards Update No. 2017-11, Earnings Per Share (Topic 260), Distinguishing Liabilities from Equity (Topic 480), and Derivatives and Hedging (Topic 815) (“ASU 2017-11”). The Company also corrected the amounts disclosed for the discount and issuance costs of notes payable for 2016 on the face of the balance sheet from $705 to $619. There were no other changes to the original Form 10-Q or the Company’s financial statements for the quarterly period ended September 30, 2017. Concurrently with this Amendment, the Company is filing a Current Report on Form 8-K to retroactively revise the Company’s financial statements included in its Annual Report on Form 10-K for the fiscal year ended December 31, 2016 to reflect changes from the early adoption of ASU 2017-11. Under ASU 2017-11, the Company changed its method of accounting for certain warrants that were initially recorded as liabilities.