Document And Entity Information - shares	9 Months Ended
	Mar. 31, 2021	Nov. 05, 2021
Document Information Line Items
Entity Registrant Name	U.S. GLOBAL INVESTORS, INC.
Trading Symbol	GROW
Document Type	10-Q/A
Current Fiscal Year End Date	--06-30
Amendment Flag	true
Amendment Description	Restatement of Unaudited Consolidated Financial Statements We have restated our unaudited consolidated financial statements for the three and nine months ended March 31, 2021, in order to adjust certain fair value measurements related to our investments in HIVE Blockchain Technologies, Ltd. (“HIVE”). For a discussion of the HIVE valuation, the adjusted fair value measurements, and the impact of the restatement adjustments on the unaudited consolidated financial statements for the third quarter of fiscal 2021, see Note 2 of Notes to Consolidated Financial Statements included in Part I, Item 1 — Financial Statements. We also identified other adjustments described in Note 2 that we have corrected as part of this restatement. Internal Control Over Financial Reporting Management reassessed its evaluation of the effectiveness of the Company’s internal control over financial reporting as of March 31, 2021, and concluded that a deficiency in the design and operating effectiveness of the internal controls represented a material weakness in the internal control over financial reporting and, therefore, the Company did not maintain effective internal control over financial reporting as of March 31, 2021. For a description of the material weakness identified by management and management’s plan to remediate the material weakness, see Part I, Item 4 — Controls and Procedures. Amended Reports This Amended Quarterly Report on Form 10-Q/A does not reflect events occurring after the original filing date of May 10, 2021, and does not modify or update disclosures in the original filing that may have been affected by subsequent events, except for the effects of the restatement described in Note 2 of Notes to Consolidated Financial Statements included in Part I, Item 1 — Financial Statements. Other disclosures not affected by the restatement are unchanged and reflect the disclosures made at the time of original filing.
Entity Central Index Key	0000754811
Entity Current Reporting Status	No
Entity Filer Category	Non-accelerated Filer
Document Period End Date	Mar. 31, 2021
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q3
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Shell Company	false
Document Quarterly Report	true
Document Transition Report	false
Entity File Number	0-13928
Entity Incorporation, State or Country Code	TX
Entity Tax Identification Number	74-1598370
Entity Address, Address Line One	7900 Callaghan Road
Entity Address, City or Town	San Antonio
Entity Address, State or Province	TX
Entity Address, Postal Zip Code	78229
City Area Code	210
Local Phone Number	308-1234
Title of 12(b) Security	Class A common stock, $0.025 par value per share
Security Exchange Name	NASDAQ
Entity Interactive Data Current	No
Common Class A [Member]
Document Information Line Items
Entity Common Stock, Shares Outstanding		12,955,307
Common Class B [Member]
Document Information Line Items
Entity Common Stock, Shares Outstanding		0
Common Class C [Member]
Document Information Line Items
Entity Common Stock, Shares Outstanding		2,068,635