v3.26.1
Document And Entity Information
Apr. 28, 2026
Document Information [Line Items]  
Entity, Registrant Name Archimedes Tech SPAC Partners II Co.
Document, Type 8-K
Document, Period End Date Apr. 28, 2026
Entity, Incorporation, State or Country Code E9
Entity, File Number 001-42514
Entity, Address, Address Line One 2093 Philadelphia Pike #1968
Entity, Address, City or Town Claymont
Entity, Address, State or Province DE
Entity, Address, Postal Zip Code 19703
City Area Code 725
Local Phone Number 312-2430
Written Communications true
Soliciting Material false
Pre-commencement Tender Offer false
Pre-commencement Issuer Tender Offer false
Entity, Emerging Growth Company true
Entity, Ex Transition Period false
Amendment Flag false
Entity, Central Index Key 0002028516
UnitsEachConsistingOfOneOrdinaryShareAndOnehalfOfOneRedeemableWarrant Custom [Member]  
Document Information [Line Items]  
Title of 12(b) Security Units, each consisting of one Ordinary Share and one-half of one redeemable Warrant
Trading Symbol ATIIU
Security Exchange Name NASDAQ
OrdinarySharesParValue00001PerShare Custom [Member]  
Document Information [Line Items]  
Title of 12(b) Security Ordinary Shares, par value $0.0001 per share
Trading Symbol ATII
Security Exchange Name NASDAQ
WarrantsEachWholeWarrantExercisableForOneOrdinaryShare Custom [Member]  
Document Information [Line Items]  
Title of 12(b) Security Warrants, each whole warrant exercisable for one Ordinary Share
Trading Symbol ATIIW
Security Exchange Name NASDAQ