Annual report pursuant to Section 13 and 15(d)

Nature of Business (Details)

v3.10.0.1
Nature of Business (Details) - USD ($)
$ / shares in Units, $ in Thousands
1 Months Ended 12 Months Ended
Feb. 28, 2018
Jan. 31, 2018
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Stock Offering          
Net Loss     $ 62,279 $ 54,010 $ 47,743
Accumulated deficit     (217,545) $ (155,266)  
Cash equivalents and marketable securities     99,700    
Common Stock [Member]          
Stock Offering          
Shares issued       2,592,591 4,600,000
Net Loss        
Common Stock [Member] | At Market Sales Facility [Member]          
Stock Offering          
Shares issued     1,373,677    
Aggregate gross proceeds     $ 16,600    
Common Stock [Member] | Public Offering          
Stock Offering          
Shares issued 4,188,481        
Share price (in dollars per share) $ 9.55        
Aggregate gross proceeds $ 40,000        
Underwriting commissions and fees $ 2,900        
Common Stock [Member] | Over Allotment          
Stock Offering          
Shares issued 628,272        
Share price (in dollars per share) $ 9.55        
Aggregate gross proceeds $ 6,000        
Underwriting commissions and fees $ 400        
Common Stock [Member] | Private Placement          
Stock Offering          
Shares issued     144,505    
Common Stock [Member] | Private Placement | Incyte          
Stock Offering          
Shares issued 144,505 793,021      
Aggregate gross proceeds $ 1,400 $ 10,000