v3.19.3.a.u2
Net Income (Loss) Per Share - Narrative (Details) - $ / shares
shares in Thousands
12 Months Ended
May 14, 2019
Jan. 18, 2018
Dec. 31, 2019
May 16, 2019
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Subsidiary, Sale of Stock [Line Items]              
Common stock shares outstanding (in shares)     1,716,681   457,189    
IPO              
Subsidiary, Sale of Stock [Line Items]              
Stock issued during period (in shares) 180,000            
Stock price (in dollars per share) $ 45.00     $ 45.00      
Conversion of shares (in shares) 905,000            
Holders of 2021 Convertible Notes and 2022 Convertible Notes | IPO              
Subsidiary, Sale of Stock [Line Items]              
Conversion of Convertible Notes to common stock in connection with initial public offering (in shares) 94,000            
Common Stock              
Subsidiary, Sale of Stock [Line Items]              
Common stock shares outstanding (in shares)     1,716,681   457,189 443,394 455,051
Conversion of Convertible Notes to common stock in connection with initial public offering (in shares)     93,978        
Common Stock | Holders of 2021 Convertible Notes and 2022 Convertible Notes | IPO              
Subsidiary, Sale of Stock [Line Items]              
Conversion of Convertible Notes to common stock in connection with initial public offering (in shares) 94,000            
Class B common stock              
Subsidiary, Sale of Stock [Line Items]              
Conversion of common stock (in shares)   390,000          
Class A common stock              
Subsidiary, Sale of Stock [Line Items]              
Common stock shares outstanding (in shares)   450,000