Quarterly report pursuant to Section 13 or 15(d)

Convertible Preferred Stock and Stockholders' Equity - Additional Information (Details)

v3.19.2
Convertible Preferred Stock and Stockholders' Equity - Additional Information (Details) - USD ($)
$ / shares in Units, $ in Thousands
 1 Months Ended 3 Months Ended 12 Months Ended
Oct. 23, 2017
Jan. 31, 2019
Dec. 31, 2018
Mar. 31, 2019
Dec. 31, 2018
Nov. 02, 2018
Nov. 01, 2018
Class Of Stock [Line Items]              
Authorized capital stock 33,853,333            
Common stock, shares authorized 18,666,666   100,000,000 100,000,000 100,000,000 100,000,000  
Capital stock par value $ 0.001         $ 0.001  
Convertible preferred stock           5,000,000  
Dividends, value $ 6,539            
Dividends, fair value             $ 10,152
Preferred shares converted into common stock             13,277,864
Preferred stock, shares issued       0      
Proceeds from issuance of common stock, net of costs       $ 1,604      
Securities Purchase Agreement              
Class Of Stock [Line Items]              
Common stock, number of shares available for sale           2,089,136  
Proceeds from issuance of common stock, net of costs   $ 1,634 $ 8,295        
Issuance cost         $ 831    
Common Stock              
Class Of Stock [Line Items]              
Shares issued and sold       227,628      
Common Stock | Securities Purchase Agreement              
Class Of Stock [Line Items]              
Shares issued and sold   227,628     1,270,905    
Common stock, shares issued price per share     $ 7.18   $ 7.18    
Convertible Preferred Stock              
Class Of Stock [Line Items]              
Convertible preferred stock 15,186,664            
Series A-3 Convertible Preferred Stock              
Class Of Stock [Line Items]              
Convertible preferred stock 1,266,666            
Series A-2 Convertible Preferred Stock              
Class Of Stock [Line Items]              
Convertible preferred stock 1,186,666            
Number of shares issued as dividends         49,456    
Series A-1 Convertible Preferred Stock [Member]              
Class Of Stock [Line Items]              
Convertible preferred stock 1,733,333            
Number of shares issued as dividends         66,255    
Series A Convertible Preferred Stock              
Class Of Stock [Line Items]              
Convertible preferred stock 9,333,333            
Number of shares issued as dividends         944,694    
Series B Convertible Preferred Stock              
Class Of Stock [Line Items]              
Convertible preferred stock 1,666,666