Annual report pursuant to Section 13 and 15(d)

Document and Entity Information

Document and Entity Information - USD ($)
12 Months Ended
Sep. 30, 2023
Sep. 30, 2022
Sep. 30, 2021
Dec. 01, 2023
Mar. 31, 2023
Cover [Abstract]          
Document Type 10-K        
Amendment Flag false        
Document Period End Date Sep. 30, 2023        
Document Fiscal Year Focus 2023        
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 Accelerated Filer        
Entity Small Business true        
Entity Emerging Growth Company false        
Entity Voluntary Filers No        
Entity Well-known Seasoned Issuer No        
Entity Public Float         $ 108,523,062
Entity Common Stock, Shares Outstanding       14,190,977  
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 85288        
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 2024 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, 2023, are incorporated by reference into Items 10-14 of Part III of this Form 10-K.

ICFR Auditor Attestation Flag true        
Document Financial Statement Error Correction [Flag] false        
Auditor Firm ID 248 199 248    
Auditor Location Phoenix, Arizona Phoenix, Arizona Phoenix, Arizona