Cover Page
 3 Months Ended
Mar. 31, 2021
shares
Document Information [Line Items]  
Document Type 10-Q
Amendment Flag false
Document Quarterly Report true
Document Transition Report false
Document Period End Date Mar. 31, 2021
Document Fiscal Year Focus 2021
Document Fiscal Period Focus Q1
Current Fiscal Year End Date --12-31
Entity Registrant Name Prime Impact Acquisition I
Entity Central Index Key 0001819175
Entity Incorporation, State or Country Code E9
Entity Address, Country CA
Title of 12(b) Security Class A ordinary shares, par value $0.0001 per share
Trading Symbol PIAI
Security Exchange Name NYSE
Entity Current Reporting Status No
Entity Interactive Data Current Yes
Entity Filer Category Non-accelerated Filer
Entity Small Business true
Entity Emerging Growth Company true
Entity Ex Transition Period false
Entity Shell Company true
Capital Units [Member]  
Document Information [Line Items]  
Title of 12(b) Security Units, each consisting of one Class A ordinary share and one-third of a Warrant to acquire one Class A ordinary share
Trading Symbol PIAI.U
Security Exchange Name NYSE
Warrant [Member]  
Document Information [Line Items]  
Title of 12(b) Security Warrants, each whole warrant exercisable for one Class A ordinary share at an exercise price of $11.50
Trading Symbol PIAI.W
Security Exchange Name NYSE
Entity Common Stock, Shares Outstanding 14,322,337
Common Class A [Member]  
Document Information [Line Items]  
Entity Common Stock, Shares Outstanding 25,803,712
Common Class B [Member]  
Document Information [Line Items]  
Entity Common Stock, Shares Outstanding 8,102,103