Quarterly report pursuant to Section 13 or 15(d)

Stock-based Compensation - Schedule of Recognized Stock-Based Compensation (Details)

v3.19.1
Stock-based Compensation - Schedule of Recognized Stock-Based Compensation (Details) - USD ($)
3 Months Ended
Mar. 31, 2019
Mar. 31, 2018
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]    
Share-based compensation expense $ 804,000 $ 1,748,000
Research and Development [Member]    
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]    
Share-based compensation expense 299,000 573,000
General and Administrative [Member]    
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]    
Share-based compensation expense $ 505,000 $ 1,175,000