Annual report pursuant to Section 13 and 15(d)

Stock Plans (Details 3)

v3.8.0.1
Stock Plans (Details 3) - USD ($)
$ / shares in Units, $ in Thousands
12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]      
Total stock-based compensation expenses $ 1,687 $ 1,039 $ 1,026
Increase in basic net income (loss) per share (in dollars per share) $ (0.08) $ (0.05) $ (0.05)
Increase in diluted net income (loss) per share (in dollars per share) $ (0.08) $ (0.05) $ (0.05)
Research and development [Member]      
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]      
Total stock-based compensation expenses $ 519 $ 386 $ 341
General and administrative [Member]      
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]      
Total stock-based compensation expenses $ 1,168 $ 653 $ 685