Quarterly report pursuant to Section 13 or 15(d)

Stock-Based Compensation (Narrative) (Details)

v3.7.0.1
Stock-Based Compensation (Narrative) (Details) - USD ($)
3 Months Ended 6 Months Ended
Jun. 30, 2017
Jun. 30, 2017
Jun. 30, 2016
Employee Stock Options [Member]      
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]      
Stock options granted (in shares)   496,384 422,973
Unrecognized costs related to share based compensation $ 9,241,000 $ 9,241,000  
Weighted average period of recognition of unrecognized costs related to stock options, years 2 years 8 months 20 days    
Restricted Stock Units [Member]      
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]      
Unrecognized costs related to share based compensation $ 18,265,000 $ 18,265,000  
Weighted average period of recognition of unrecognized costs related to stock options, years 2 years 6 months 22 days    
Restricted stock units granted (in shares)   245,953 188,719