Cover Page - shares	3 Months Ended
	Mar. 31, 2020	Apr. 30, 2020
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Transition Report	false
Entity File Number	000-32259
Entity Registrant Name	ALIGN TECHNOLOGY INC
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	94-3267295
Entity Address, Address Line One	2820 Orchard Parkway
Entity Address, City or Town	San Jose
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	95134
City Area Code	408
Local Phone Number	470-1000
Title of 12(b) Security	Common Stock, $0.0001 par value
Trading Symbol	ALGN
Security Exchange Name	NASDAQ
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Shell Company	false
Entity Central Index Key	0001097149
Current Fiscal Year End Date	--12-31
Document Period End Date	Mar. 31, 2020
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q1
Amendment Flag	false
Entity Common Stock, Shares Outstanding		78,762,958