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Stock-based Compensation - Employee Stock Purchase Plan (Details) - USD ($)
12 Months Ended
May 09, 2018
Dec. 31, 2019
Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Aggregate number of shares of common stock issued or transferred under the incentive stock awards plan (in shares)   3,772,517  
Employee Stock      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
ESPP purchase price of common stock, percent of market price, on first and last day of trading date 85.00%    
Fixed contribution rate 10.00%    
Maximum contribution amount $ 25,000    
Compensation cost for ESPP   $ 500,000 $ 200,000
Number of shares issued under the ESPP   46,642 25,239
Weighted average grant date fair value (in dollars per share)   $ 42.07 $ 35.74
Aggregate number of shares of common stock issued or transferred under the incentive stock awards plan (in shares)   128,134