XML 54 R43.htm IDEA: XBRL DOCUMENT v3.19.2
Redeemable Convertible Preferred Stock and Common Stock (Details)
 1 Months Ended
Jul. 30, 2018
shares
Dec. 31, 2015
$ / shares
shares
Oct. 31, 2012
shares
Jun. 30, 2019
shares
Dec. 31, 2018
shares
Class of Stock [Line Items]          
Conversion ratio   1      
Common stock, authorized (in shares) 500,000,000     500,000,000 500,000,000
Preferred stock, authorized (in shares) 10,000,000        
Preferred stock, shares issued and outstanding (in shares)       0 0
Series A Redeemable Convertible Preferred Stock          
Class of Stock [Line Items]          
Stock sold (in shares)   15,847,500 15,847,500    
Redeemable convertible preferred stock, par value (in usd per share) | $ / shares   $ 0.01      
Series B Redeemable Convertible Preferred Stock          
Class of Stock [Line Items]          
Stock sold (in shares)   39,538,354      
Redeemable convertible preferred stock, par value (in usd per share) | $ / shares   $ 0.01      
Redeemable convertible preferred stock, shares authorized (in shares)   42,000,000      
Common Stock | IPO          
Class of Stock [Line Items]          
Stock sold (in shares) 12,535,000        
Issuance of common stock upon conversion of redeemable convertible preferred stock (in shares) 55,385,854