XML 18 R1.htm IDEA: XBRL DOCUMENT v3.10.0.1
Document and Entity Information - shares
 6 Months Ended
Sep. 30, 2018
Nov. 02, 2018
Document And Entity Information    
Entity Registrant Name 8X8 INC /DE/  
Entity Central Index Key 0001023731  
Document Type 10-Q  
Document Period End Date Sep. 30, 2018  
Amendment Flag false  
Current Fiscal Year End Date --03-31  
Entity Small Business false  
Is Entity's Reporting Status Current? Yes  
Entity Filer Category Large Accelerated Filer  
Entity Emerging Growth Company false  
Entity Common Stock, Shares Outstanding   95,371,181
Document Fiscal Period Focus Q2  
Document Fiscal Year Focus 2019