Quarterly report pursuant to Section 13 or 15(d)

Stock-Based Compensation (Details)

v3.19.1
Stock-Based Compensation (Details) - Stock Option [Member] - USD ($)
$ / shares in Units, $ in Thousands
3 Months Ended 12 Months Ended
Mar. 31, 2019
Dec. 31, 2018
Number of Shares, Outstanding Beginning Balance 2,364,823 2,364,823
Number of Shares, Granted  
Number of Shares, Exercised (50,772)  
Number of Shares, Cancelled/Expired (269,598)  
Number of Shares, Outstanding, Ending Balance 2,044,453 2,364,823
Number of Shares, Exercisable 1,163,786  
Weighted Average Exercise Price, Outstanding Beginning Balance $ 0.90  
Weighted Average Exercise Price, Granted  
Weighted Average Exercise Price, Exercised 0.58  
Weighted Average Exercise Price, Cancelled/Expired 1.71  
Weighted Average Exercise Price, Outstanding Ending Balance 0.81 $ 0.90
Weighted Average Exercise Price, Exercisable $ 0.59  
Weighted Average Remaining Contractual Term (years), Outstanding 7 years 5 months 12 days 8 years 1 month 13 days
Weighted Average Remaining Contractual Term (years), Exercisable 6 years 5 months 16 days  
Aggregate Intrinsic Value, Outstanding $ 26,341 $ 71,332
Aggregate Intrinsic Value, Exercisable $ 15,250