v3.19.3
Cover Page - $ / shares
9 Months Ended
Sep. 30, 2019
Oct. 31, 2019
Dec. 31, 2018
Cover page.      
Document Type 10-Q    
Document Quarterly Report true    
Document Period End Date Sep. 30, 2019    
Document Transition Report false    
Entity File Number 001-34186    
Entity Registrant Name VANDA PHARMACEUTICALS INC.    
Entity Incorporation, State or Country Code DE    
Entity Tax Identification Number 03-0491827    
Entity Address, Address Line One 2200 Pennsylvania Avenue, N.W.,    
Entity Address, Address Line Two Suite 300 E    
Entity Address, City or Town Washington,    
Entity Address, State or Province DC    
Entity Address, Postal Zip Code 20037    
City Area Code 202    
Local Phone Number 734-3400    
Title of 12(b) Security Common Stock, par value $0.001 per share    
Trading Symbol VNDA    
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 Company false    
Entity Shell Company false    
Entity Common Stock, Shares Outstanding   53,337,085  
Entity Central Index Key 0001347178    
Current Fiscal Year End Date --12-31    
Common stock, par value (in dollars per share) $ 0.001   $ 0.001
Document Fiscal Year Focus 2019    
Document Fiscal Period Focus Q3    
Amendment Flag false