Document and Entity Information - USD ($)
12 Months Ended
Jun. 30, 2019
Aug. 15, 2019
Dec. 31, 2018
Document And Entity Information [Abstract]      
Entity Registrant Name ACCURAY INC    
Entity Central Index Key 0001138723    
Document Type 10-K    
Document Period End Date Jun. 30, 2019    
Amendment Flag false    
Current Fiscal Year End Date --06-30    
Entity Well-known Seasoned Issuer No    
Entity Voluntary Filers No    
Entity Current Reporting Status Yes    
Trading Symbol ARAY    
Entity Filer Category Accelerated Filer    
Entity Public Float     $ 226,552,976
Entity Common Stock, Shares Outstanding   88,777,310  
Document Fiscal Year Focus 2019    
Document Fiscal Period Focus FY    
Entity Shell Company false    
Entity Small Business false    
Entity Emerging Growth Company false    
Entity File Number 001-33301    
Entity Tax Identification Number 208370041    
Entity Address, Address Line One 1310 Chesapeake Terrace    
Entity Address, City or Town Sunnyvale    
Entity Address, State or Province California    
Entity Address, Postal Zip Code 94089    
City Area Code 408    
Local Phone Number 7164600