Quarterly report pursuant to Section 13 or 15(d)

Stock-Based Payments - Stock-Based Compensation Expense (Details)

v3.7.0.1
Stock-Based Payments - Stock-Based Compensation Expense (Details) - USD ($)
$ in Thousands
 3 Months Ended 6 Months Ended
Jun. 30, 2017
Jun. 30, 2016
Jun. 30, 2017
Jun. 30, 2016
Stock-based compensation expense for stock options and restricted common stock granted        
Stock-based compensation expense $ 1,156 $ 1,148 $ 2,040 $ 1,810
Employee Stock options        
Stock-based compensation expense for stock options and restricted common stock granted        
Unrecognized compensation cost related to non-vested stock options granted to employees 13,500   $ 13,500  
Weighted average period over which future compensation cost is expected to be recognized for awards granted to employees     2 years 10 months 24 days  
Research and development        
Stock-based compensation expense for stock options and restricted common stock granted        
Stock-based compensation expense 448 929 $ 778 1,489
General and administrative        
Stock-based compensation expense for stock options and restricted common stock granted        
Stock-based compensation expense $ 708 $ 219 $ 1,262 $ 321