Quarterly report pursuant to Section 13 or 15(d)

Stock-based Compensation - Options (Details)

v3.10.0.1
Stock-based Compensation - Options (Details)
 3 Months Ended 6 Months Ended
Jun. 30, 2018
USD ($)
shares
Jun. 30, 2017
USD ($)
Jun. 30, 2018
USD ($)
item
$ / shares
shares
Jun. 30, 2017
USD ($)
Stock Based Compensation        
Share-based compensation $ 1,112,000 $ 1,100,000 $ 2,652,000 $ 2,055,000
Additional disclosures        
Shares of common stock available for grant | shares 14,597,716   14,597,716  
Options exercised during the period (in shares) | shares     823,130  
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     $ 1,600,000  
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 7 months 6 days 6 years 7 months 6 days 6 years 8 months 12 days 6 years 9 months 18 days
Dividend yield (as a percent) 0.00% 0.00% 0.00% 0.00%
Expected volatility (as a percent) 66.20% 63.70% 65.00% 63.00%
Additional disclosures        
Options granted (in shares) | shares     4,486,225  
Grant-date weighted-average fair value (in dollars per share) | $ / shares     $ 2.68  
Total unrecognized compensation costs $ 15,500,000   $ 15,500,000  
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     $ 488,000  
Additional disclosures        
Options granted (in shares) | shares     2,790,000  
Grant date fair value of performance stock options awards     $ 5,900,000  
Total unrecognized compensation costs $ 4,300,000   $ 4,300,000  
Employee stock option | Recipient of performance shares | Vesting upon achievement of corporate performance-based milestones        
Additional disclosures        
Options granted (in shares) | shares     1,160,000