v3.26.1
Cover - shares
 6 Months Ended
Jun. 30, 2026
Jul. 30, 2026
Cover [Abstract]    
Document Type 10-Q  
Document Quarterly Report true  
Document Period End Date Jun. 30, 2026  
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 NW  
Entity Address, Address Line Two Suite 300E  
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 Accelerated Filer  
Entity Small Business false  
Entity Emerging Growth Company false  
Entity Shell Company false  
Entity Common Stock, Shares Outstanding   60,462,687
Entity Central Index Key 0001347178  
Current Fiscal Year End Date --12-31  
Document Fiscal Year Focus 2026  
Document Fiscal Period Focus Q2  
Amendment Flag false