| Cover | Nov. 05, 2020 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Document Period End Date | Nov. 5, 2020 |
| Entity Registrant Name | INTERDIGITAL, INC. |
| Entity Central Index Key | 0001405495 |
| Amendment Flag | false |
| Entity Incorporation, State or Country Code | PA |
| Entity File Number | 1-33579 |
| Entity Tax Identification Number | 82-4936666 |
| Entity Address, Address Line One | 200 Bellevue Parkway |
| Entity Address, Address Line Two | Suite 300 |
| Entity Address, City or Town | Wilmington |
| Entity Address, State or Province | DE |
| Entity Address, Postal Zip Code | 19809-3727 |
| City Area Code | 302 |
| Local Phone Number | 281-3600 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Common Stock, par value $0.01 per share |
| Trading Symbol | IDCC |
| Security Exchange Name | NASDAQ |
| Entity Emerging Growth Company | false |
