XML 21 R1.htm IDEA: XBRL DOCUMENT v3.21.1
Cover Page - shares
 3 Months Ended
Mar. 31, 2021
Apr. 22, 2021
Cover [Abstract]    
Amendment Flag false  
Document Fiscal Year Focus 2021  
Document Fiscal Period Focus Q1  
Entity Central Index Key 0001093557  
Current Fiscal Year End Date --12-31  
Document Type 10-Q  
Document Quarterly Report true  
Document Period End Date Mar. 31, 2021  
Document Transition Report false  
Entity File Number 000-51222  
Entity Registrant Name DEXCOM, INC.  
Entity Incorporation, State or Country Code DE  
Entity Tax Identification Number 33-0857544  
Entity Address, Address Line One 6340 Sequence Drive  
Entity Address, City or Town San Diego  
Entity Address, State or Province CA  
Entity Address, Postal Zip Code 92121  
City Area Code 858  
Local Phone Number 200-0200  
Title of 12(b) Security Common Stock, $0.001 Par Value Per Share  
Trading Symbol DXCM  
Security Exchange Name NASDAQ  
Entity Current Reporting Status Yes  
Entity Interactive Data Current Yes  
Entity Filer Category Large Accelerated Filer  
Entity Small Business false  
Entity Emerging Growth false  
Entity Shell Company false  
Entity Common Stock, Shares Outstanding   96,705,873