Net Loss Per Share
 9 Months Ended
Sep. 30, 2016
Earnings Per Share [Abstract]  
Net Loss Per Share
Net Loss Per Share
Basic net loss per share is calculated by dividing the net loss by the weighted average number of common shares outstanding during the period. Diluted net loss per share is computed by dividing the net loss by the weighted average number of common shares and common share equivalents outstanding for the period. Common stock equivalents are only included when their effect is dilutive. Potentially dilutive securities which include warrants and outstanding stock options have been excluded from the computation of diluted net loss per share as the effect of their inclusion would be anti-dilutive. For all periods presented, diluted and basic net loss per share were identical due to the Company’s net loss position.
The following table presents the computation of net loss per share (in thousands, except share and per share data):
 
Three Months Ended
September 30,
 
Nine Months Ended
September 30,
 
2016
 
2015
 
2016
 
2015
Numerator
 
 
 
 
 
 
 
Net loss from continuing operations
$
(7,125
)
 
$
(6,793
)
 
$
(21,742
)
 
$
(19,666
)
Net income from discontinued operations
—

 
219

 
—

 
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
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
$
(0.32
)
 
$
(0.34
)
 
$
(1.01
)
 
$
(0.99
)
Net income per share from discontinued operations
—

 
0.01

 
—

 
0.01

Net loss per share
$
(0.32
)
 
$
(0.33
)
 
$
(1.01
)
 
$
(0.98
)

The following weighted average outstanding shares of potentially dilutive securities were excluded from the computation of diluted net loss per share of common stock for the periods presented as the effect of their inclusion would have been anti-dilutive:
 
Three Months Ended
September 30,
 
Nine Months Ended
September 30,
 
2016
 
2015
 
2016
 
2015
Common stock warrants
1,021,651
 
997,839
 
1,024,705
 
954,345
Common stock options
3,646,426
 
2,340,054
 
3,652,762
 
2,134,428
Total
4,668,077
 
3,337,893
 
4,677,467
 
3,088,773

The Company has utilized the control number concept in the computation of diluted earnings per share to determine whether potential common stock instruments are dilutive. The control number used is loss from continuing operations. The control number concept requires that the same number of potentially dilutive securities applied in computing diluted earnings per share from continuing operations be applied to all other categories of income or loss, regardless of their anti-dilutive effect on such categories. Therefore, no dilutive effect has been recognized in the calculation of income from discontinued operations per share for the three and nine months ended September 30, 2015.