Quarterly report pursuant to Section 13 or 15(d)

Stock Based Option Compensation and Restricted Stock Compensation (Details)

v3.8.0.1
Stock Based Option Compensation and Restricted Stock Compensation (Details) - USD ($)
 3 Months Ended
Mar. 31, 2018
Mar. 31, 2017
Share-based and Restricted Stock Compensation Expense [Abstract]    
Stock-based compensation expense included in operating expense $ 1,900,000 $ 1,492,000
Stock Options [Member]    
Share-based and Restricted Stock Compensation Expense [Abstract]    
Stock-based compensation expense included in operating expense 1,900,000 1,492,000
Stock Options [Member] | Research and Development Expense [Member]    
Share-based and Restricted Stock Compensation Expense [Abstract]    
Stock-based compensation expense included in operating expense 1,056,000 356,000
Stock Options [Member] | General and Administrative [Member]    
Share-based and Restricted Stock Compensation Expense [Abstract]    
Stock-based compensation expense included in operating expense 844,000 1,136,000
Restricted Stock [Member]    
Share-based and Restricted Stock Compensation Expense [Abstract]    
Stock-based compensation expense included in operating expense 172,000 362,000
Restricted Stock [Member] | Research and Development Expense [Member]    
Share-based and Restricted Stock Compensation Expense [Abstract]    
Stock-based compensation expense included in operating expense 0 0
Restricted Stock [Member] | General and Administrative [Member]    
Share-based and Restricted Stock Compensation Expense [Abstract]    
Stock-based compensation expense included in operating expense $ 172,000 $ 362,000