Quarterly report pursuant to Section 13 or 15(d)

Stock-Based Compensation (Details)

v3.19.3
Stock-Based Compensation (Details) - USD ($)
$ / shares in Units, $ in Thousands
3 Months Ended 9 Months Ended 12 Months Ended
Sep. 30, 2019
Jun. 30, 2019
Sep. 30, 2019
Dec. 31, 2018
Mar. 31, 2019
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     $ 7,476    
Fair value of options vested     $ 289    
2018 Stock Option and Incentive Plan          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Issuance of common stock shares (in shares)     1,733,430    
Common stock reserved for issuance (in shares) 984,702   984,702 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   272,942 272,942  
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) 13,091   13,091 40,707  
Accrued expenses $ 7   $ 7   $ 34
Unamortized fair value of restricted stock units 6,800   $ 6,800    
Weighed-average period of costs amortized     2 years 10 months 24 days    
Unrecognized stock compensation expense $ 285   $ 285    
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) 1,603,000 620,363      
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) $ 2.11 $ 7.34 $ 2.11    
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%