Document And Entity Information - USD ($)	12 Months Ended
	Jun. 30, 2021	Nov. 29, 2021	Dec. 31, 2020
Document Information Line Items
Entity Registrant Name	U.S. GLOBAL INVESTORS, INC.
Trading Symbol	GROW
Document Type	10-K
Current Fiscal Year End Date	--06-30
Entity Public Float			$ 59,914,215
Amendment Flag	false
Entity Central Index Key	0000754811
Entity Current Reporting Status	No
Entity Voluntary Filers	No
Entity Filer Category	Non-accelerated Filer
Entity Well-known Seasoned Issuer	No
Document Period End Date	Jun. 30, 2021
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	FY
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Shell Company	false
Document Annual 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		12,952,861
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