Quarterly report pursuant to Section 13 or 15(d)

Stock Plans

v3.5.0.2
Stock Plans
 6 Months Ended
Jun. 30, 2016
Stock Plans [Abstract]  
Stock Plans [Text Block]
2. Stock Plans
 
The following table summarizes the stock-based compensation expense recorded for awards under the stock option plans for the three and six month periods ended June 30, 2016 and 2015:
 
 
 
Three Months Ended
June 30,
 
Six Months Ended
June 30,
 
(in thousands, except per share amounts)
 
2016
 
2015
 
2016
 
2015
 
Research and development
 
$
85
 
$
35
 
$
217
 
$
238
 
General and administrative
 
 
164
 
 
41
 
 
364
 
 
329
 
Total stock-based compensation expenses
 
$
249
 
$
76
 
$
581
 
$
567
 
 
No tax benefit was recognized related to stock-based compensation expense since we have accumulated operating losses and we have established a full valuation allowance to offset all the potential tax benefits associated with our deferred tax assets.
 
We use the Black-Scholes-Merton option-pricing model with the following assumptions to estimate the stock-based compensation expense for the three and six month periods ended June 30, 2016 and 2015:
 
 
 
Three Months Ended
June 30,
 
Six Months Ended
June 30,
 
 
 
2016
 
2015
 
2016
 
2015
 
Weighted-average risk-free interest rate
 
 
1.5
%
 
1.7
%
 
1.5
%
 
1.8
%
Expected dividend payments
 
 
—
 
 
—
 
 
—
 
 
—
 
Expected holding period (years) 1
 
 
6.5
 
 
4.5
 
 
6.5
 
 
6.4
 
Weighted-average volatility factor 2
 
 
0.92
 
 
1.65
 
 
0.92
 
 
1.61
 
Estimated forfeiture rates 3
 
 
29
%
 
30
%
 
29
%
 
30
%
 
(1)
Expected holding period is based on historical experience of similar awards, giving consideration to the contractual terms of the stock-based awards, vesting schedules and the expectations of future employee behavior.
(2)
Weighted average volatility is based on the historical volatility of our common stock.
(3)
Estimated forfeiture rates are based on historical data.
 
No options were granted during the three month periods ended June 30, 2016 and 2015.
 
The following table summarizes option activity for the six month period ended June 30, 2016:
 
(in thousands, except per share amounts)
 
Options
 
Weighted
Average
Exercise
Price
 
Weighted
Average
Remaining
Option
Term
 
Aggregate
Intrinsic
Value
 
Outstanding at January 1, 2016
 
 
1,883
 
$
5.83
 
 
5.14
 
$
388
 
Granted
 
 
168
 
 
5.10
 
 
 
 
 
 
 
Exercised
 
 
(8)
 
 
3.37
 
 
 
 
 
 
 
Expired or cancelled
 
 
(17)
 
 
7.70
 
 
 
 
 
 
 
Forfeited
 
 
—
 
 
—
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Outstanding at June 30, 2016
 
 
2,026
 
$
5.76
 
 
6.12
 
$
1,346
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Exercisable at June 30, 2016
 
 
1,594
 
$
5.94
 
 
5.20
 
$
1,186
 
  
No shares of restricted stock were awarded to employees, directors and consultants during the three month periods ended June 30, 2016 and 2015.
  
As of June 30, 2016, there was approximately $1.1 million of total unrecognized compensation expense related to non-vested stock options. This expense is expected to be recognized over a weighted-average period of 1.4 years.