Quarterly report pursuant to Section 13 or 15(d)

Stock-Based Compensation (Details)

v3.19.2
Stock-Based Compensation (Details) - USD ($)
$ / shares in Units, $ in Thousands
3 Months Ended 6 Months Ended 12 Months Ended
Jun. 30, 2019
Jun. 30, 2019
Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Issuance of common stock shares (in shares)     1,085,096
Aggregate intrinsic value of options exercised $ 7,324    
Fair value of options vested $ 229    
2018 Stock Option and Incentive Plan      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Issuance of common stock shares (in shares)   1,954,306  
Common stock reserved for issuance (in shares) 2,403,321 2,403,321 2,729,416
2018 Employee Stock Purchase Plan      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Common stock reserved for issuance (in shares) 272,942 272,942 1,228,237
Expiration period   27 months  
ESPP, purchase price percentage   85.00%  
2009 Stock Option and Incentive Plan      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Unvested shares (in shares) 25,230 25,230 40,707
Accrued expenses $ 17 $ 17 $ 34
Unamortized fair value of restricted stock units 4,500 $ 4,500  
Weighed-average period of costs amortized   1 year 3 months 18 days  
Unrecognized stock compensation expense $ 334 $ 334  
Selling and Marketing Expense      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Maximum number of shares participant may purchase   2,000  
Restricted Stock Units (RSUs) - Employees      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Restricted stock unit awards granted (in shares) 620,363    
Restricted Stock Units (RSUs) - Non-Employee Directors      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Restricted stock unit awards granted (in shares) 45,000    
Restricted stock units awards grant date fair value (in dollars per share) $ 7.34 $ 7.34  
Employee Stock | 2018 Employee Stock Purchase Plan      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Annual percentage increase 3.00% 3.00%  
Percent of shares outstanding on last day 1.50% 1.50%  
Post-Closing Outstanding Shares | Employee Stock | 2018 Stock Option and Incentive Plan      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Annual percentage increase 10.00% 10.00%  
Outstanding Shares on Last Day of Immediately Preceding Year | Employee Stock | 2018 Stock Option and Incentive Plan      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Annual percentage increase 5.00% 5.00%