Net Loss Per Share (Schedule of Basic and Diluted Loss Per Share) (Details) - USD ($)
$ / shares in Units, $ in Thousands
3 Months Ended 9 Months Ended
Sep. 30, 2016
Sep. 30, 2015
Sep. 30, 2016
Sep. 30, 2015
Numerator        
Net loss from continuing operations $ (7,125) $ (6,793) $ (21,742) $ (19,666)
Net income from discontinued operations 0 219 0 219
Net loss $ (7,125) $ (6,574) $ (21,742) $ (19,447)
Denominator        
Weighted average common shares outstanding used to compute net loss per share, basic and diluted (in shares) 22,096,610 20,183,939 21,532,953 19,902,815
Net loss per share of common stock, basic and diluted        
Net loss per share from continuing operations (in usd per share) $ (0.32) $ (0.34) $ (1.01) $ (0.99)
Net income per share from discontinued operations (in usd per share) 0.00 0.01 0.00 0.01
Net loss per share, basic and diluted (in usd per share) $ (0.32) $ (0.33) $ (1.01) $ (0.98)