Quarterly report pursuant to Section 13 or 15(d)

Stock-Based Compensation - Options (Details)

v3.19.1
Stock-Based Compensation - Options (Details)
$ / shares in Units, $ in Thousands
 3 Months Ended
Mar. 31, 2019
USD ($)
item
$ / shares
shares
Mar. 31, 2018
USD ($)
Stock Based Compensation    
Share-based compensation | $ $ 2,953 $ 1,540
Additional disclosures    
Shares of common stock available for grant 10,641,901  
Employee stock option    
Stock Based Compensation    
Number of homogenous groups for purposes of determining fair values of options | item 3  
Contractual term of the option 10 years  
Weighted-average assumptions relating to options granted    
Risk-free interest rate (as a percent) 2.60% 2.70%
Expected term (in years) 6 years 7 months 6 days 6 years 8 months 12 days
Dividend yield (as a percent) 0.00% 0.00%
Expected volatility (as a percent) 65.90% 64.60%
Additional disclosures    
Options granted (in shares) 5,675,525  
Grant-date weighted-average fair value (in dollars per share) | $ / shares $ 1.27  
Total unrecognized compensation costs | $ $ 14,200  
Options exercised during the period (in shares) 7,583  
Employee stock option | Vesting upon achievement of corporate performance-based milestones    
Additional disclosures    
Options outstanding 1,012,500  
Total unrecognized compensation costs | $ $ 1,400  
Employee stock option | Consultant    
Stock Based Compensation    
Contractual term of the option 10 years