v3.26.1
Cover - shares
9 Months Ended
Mar. 31, 2026
May 14, 2026
Document Type 10-Q  
Amendment Flag false  
Document Quarterly Report true  
Document Transition Report false  
Document Period End Date Mar. 31, 2026  
Document Fiscal Period Focus Q3  
Document Fiscal Year Focus 2026  
Current Fiscal Year End Date --06-30  
Entity File Number 001-41655  
Entity Registrant Name NioCorp Developments Ltd.  
Entity Central Index Key 0001512228  
Entity Tax Identification Number 98-1262185  
Entity Incorporation, State or Country Code A1  
Entity Address, Address Line One 7000 South Yosemite Street  
Entity Address, Address Line Two Suite 115  
Entity Address, City or Town Centennial  
Entity Address, State or Province CO  
Entity Address, Postal Zip Code 80112  
City Area Code (720)  
Local Phone Number 334-7066  
Entity Current Reporting Status Yes  
Entity Interactive Data Current Yes  
Entity Filer Category Non-accelerated Filer  
Entity Small Business true  
Entity Emerging Growth Company false  
Entity Shell Company false  
Entity Common Stock, Shares Outstanding   145,587,048
Common Shares Without Par Value [Member]    
Title of 12(b) Security Common Shares, without par value  
Trading Symbol NB  
Security Exchange Name NASDAQ  
Warrants Each Exercisable For 1.11829212 Common Shares [Member]    
Title of 12(b) Security Warrants, each exercisable for 1.11829212 Common Shares  
Trading Symbol NIOBW  
Security Exchange Name NASDAQ  
Common Share Purchase Rights [Member]    
Title of 12(b) Security Common Share Purchase Rights  
No Trading Symbol Flag true  
Security Exchange Name NASDAQ