| Cover - shares | 9 Months Ended | |
| Sep. 30, 2022 | Oct. 28, 2022 | |
| Cover [Abstract] | ||
| Document Type | 10-Q/A | |
| Document Quarterly Report | true | |
| Document Period End Date | Sep. 30, 2022 | |
| Document Transition Report | false | |
| Entity File Number | 001-38427 | |
| Entity Registrant Name | PIEDMONT LITHIUM INC. | |
| Entity Incorporation, State or Country Code | DE | |
| Entity Tax Identification Number | 36-4996461 | |
| Entity Address, Address Line One | 42 E Catawba Street | |
| Entity Address, Address Line Two | ||
| Entity Address, City or Town | Belmont | |
| Entity Address, State or Province | NC | |
| Entity Address, Postal Zip Code | 28012 | |
| City Area Code | 704 | |
| Local Phone Number | 461-8000 | |
| Title of 12(b) Security | Common stock, par value $0.0001 per share | |
| Trading Symbol | PLL | |
| Security Exchange Name | NASDAQ | |
| Entity Current Reporting Status | Yes | |
| Entity Interactive Data Current | Yes | |
| Entity Filer Category | Large Accelerated Filer | |
| Entity Small Business | false | |
| Entity Emerging Growth Company | false | |
| Entity Shell Company | false | |
| Entity Common Stock, Shares Outstanding | 18,010,228 | |
| Amendment Flag | true | |
| Document Fiscal Year Focus | 2022 | |
| Document Fiscal Period Focus | Q3 | |
| Entity Central Index Key | 0001728205 | |
| Current Fiscal Year End Date | --12-31 | |
| Amendment Description | Piedmont Lithium Inc. (the “Company”) filed its Quarterly Report on Form 10-Q for the quarterly period ended September 30, 2022 (the “Original Form 10-Q”), with the U.S. Securities and Exchange Commission (the “SEC”) on November 4, 2022. The Company is filing this Amendment No. 1 to the Original Form 10-Q (this “Form 10-Q/A”) solely to remove certain disclosures referencing our Equity Method Investees’ prefeasibility study results that were not prepared in accordance with Item 1300 of Regulation S-K. This amendment solely relates to, and replaces, all information previously included in Item 2. Management’s Discussion and Analysis of Financial Condition and Results of Operations. |
| EQUITY METHOD INVESTMENTS IN UNCONSOLIDATED AFFILIATES - Additional Information (Details) | Sep. 30, 2022 |
| Atlantic Lithium | |
| Schedule of Equity Method Investments [Line Items] | |
| Equity interest, ownership percentage | 9% |
