Annual report pursuant to Section 13 and 15(d)

Document and Entity Information

Document and Entity Information - USD ($)
12 Months Ended
Sep. 30, 2021
Nov. 12, 2021
Mar. 31, 2021
Cover [Abstract]      
Document Type 10-K    
Amendment Flag false    
Document Period End Date Sep. 30, 2021    
Document Fiscal Year Focus 2021    
Document Fiscal Period Focus FY    
Entity Registrant Name AMTECH SYSTEMS, INC.    
Entity Central Index Key 0000720500    
Current Fiscal Year End Date --09-30    
Entity Filer Category Non-accelerated Filer    
Entity Small Business true    
Entity Emerging Growth Company false    
Entity Voluntary Filers No    
Entity Well-known Seasoned Issuer No    
Entity Public Float     $ 137,669,715
Entity Common Stock, Shares Outstanding   14,309,435  
Entity Current Reporting Status Yes    
Entity Shell Company false    
Entity File Number 0-11412    
Entity Tax Identification Number 86-0411215    
Entity Address, Address Line One 131 South Clark Drive    
Entity Address, City or Town Tempe    
Entity Address, State or Province AZ    
Entity Address, Postal Zip Code 85281    
City Area Code 480    
Local Phone Number 967-5146    
Entity Interactive Data Current Yes    
Title of 12(b) Security Common Stock, par value $0.01 per share    
Trading Symbol ASYS    
Security Exchange Name NASDAQ    
Entity Incorporation, State or Country Code AZ    
Document Annual Report true    
Document Transition Report false    
Documents Incorporated by Reference

Portions of the Definitive Proxy Statement related to the registrant’s 2022 Annual Meeting of Shareholders, which Proxy Statement will be filed under the Securities Exchange Act of 1934, as amended, within 120 days of the end of the registrant’s fiscal year ended September 30, 2021, are incorporated by reference into Items 10-14 of Part III of this Form 10-K.

ICFR Auditor Attestation Flag false