Quarterly report pursuant to Section 13 or 15(d)

Stock-based Compensation - Options (Details)

v3.10.0.1
Stock-based Compensation - Options (Details)
$ / shares in Units, $ in Thousands
 3 Months Ended 9 Months Ended
Sep. 30, 2018
USD ($)
shares
Sep. 30, 2017
USD ($)
Sep. 30, 2018
USD ($)
item
$ / shares
shares
Sep. 30, 2017
USD ($)
Stock Based Compensation        
Share-based compensation $ 2,995 $ 873 $ 5,647 $ 2,928
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  
Share-based compensation     $ 3,100  
Weighted-average assumptions relating to options granted        
Risk-free interest rate (as a percent) 2.90% 2.10% 2.70% 2.20%
Expected term (in years) 6 years 6 years 2 months 12 days 6 years 8 months 12 days 6 years 8 months 12 days
Dividend yield (as a percent) 0.00% 0.00% 0.00% 0.00%
Expected volatility (as a percent) 67.90% 64.40% 65.10% 63.20%
Additional disclosures        
Options granted (in shares) | shares     4,541,725  
Grant-date weighted-average fair value (in dollars per share) | $ / shares     $ 2.67  
Total unrecognized compensation costs $ 12,900   $ 12,900  
Shares of common stock available for grant | shares 14,932,805   14,932,805  
Options exercised during the period (in shares) | shares     1,088,449  
Employee stock option | Consultant        
Stock Based Compensation        
Contractual term of the option     10 years  
Employee stock option | Recipient of performance shares        
Stock Based Compensation        
Share-based compensation $ 1,500   $ 2,000  
Additional disclosures        
Options granted (in shares) | shares     2,790,000  
Grant date fair value of performance stock options awards     $ 5,900  
Total unrecognized compensation costs $ 2,900   $ 2,900  
Employee stock option | Recipient of performance shares | Vesting upon achievement of corporate performance-based milestones        
Additional disclosures        
Options granted (in shares) | shares     2,590,000