Annual report pursuant to Section 13 and 15(d)

Stockholders' Equity - Common Stock (Details)

v3.19.1
Stockholders' Equity - Common Stock (Details) - USD ($)
$ / shares in Units, $ in Thousands
12 Months Ended
Jun. 30, 2017
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Subsidiary, Sale of Stock [Line Items]        
Common stock, par value (in dollars per share) $ 0.0001 $ 0.0001 $ 0.0001  
Proceeds from common stock issuance   $ 0 $ 11,952 $ 0
Underwriting Agreement        
Subsidiary, Sale of Stock [Line Items]        
Proceeds from common stock issuance $ 10,400      
Over-allotment option        
Subsidiary, Sale of Stock [Line Items]        
Proceeds from common stock issuance $ 1,600      
Common Stock        
Subsidiary, Sale of Stock [Line Items]        
New share issues (shares)     4,140,000  
Common Stock | Underwriting Agreement        
Subsidiary, Sale of Stock [Line Items]        
New share issues (shares) 3,600,000      
Price per share (in dollars per share) $ 3.15      
Price per share, net proceeds (in dollars per share) $ 2.90      
Common Stock | Over-allotment option        
Subsidiary, Sale of Stock [Line Items]        
New share issues (shares) 500,000