Quarterly report pursuant to Section 13 or 15(d)

Stock Plans (Tables)

v3.4.0.3
Stock Plans (Tables)
3 Months Ended
Mar. 31, 2016
Stock Plans [Abstract]  
Schedule of Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Table Text Block]
The following table summarizes the stock-based compensation expense recorded for awards under the stock option plans for the three month periods ended March 31, 2016 and 2015:
 
 
 
Three Months Ended
 
 
 
March 31,
 
(in thousands, except per share amounts)
 
2016
 
2015
 
Research and development
 
$
132
 
$
203
 
General and administrative
 
 
200
 
 
288
 
 
 
 
 
 
 
 
 
Total stock-based compensation expenses
 
$
332
 
$
491
 
Schedule of Share-based Payment Award, Employee Stock Purchase Plan, Valuation Assumptions [Table Text Block]
We use the Black-Scholes-Merton option-pricing model with the following assumptions to estimate the stock-based compensation expense for the three month period ended March 31, 2016 and 2015:
 
 
 
Three Months Ended
 
 
 
March 31,
 
 
 
2016
 
2015
 
Weighted-average risk-free interest rate
 
 
1.53
%
 
1.8
%
Expected dividend payments
 
 
 
 
 
Expected holding period (years)1
 
 
6.5
 
 
6.4
 
Weighted-average volatility factor2
 
 
0.92
 
 
1.61
 
Estimated forfeiture rates for options granted3
 
 
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.
Schedule of Share-based Compensation, Stock Options, Activity [Table Text Block]
The following table summarizes option activity for the three month period ended March 31, 2016:
 
 
 
 
 
 
 
Weighted
 
 
 
 
 
 
 
Weighted
 
Average
 
 
 
 
 
 
 
Average
 
Remaining
 
Aggregate
 
 
 
 
 
Exercise
 
Option
 
Intrinsic
 
(in thousands, except per share amounts)
 
Options
 
Price
 
Term
 
Value
 
Outstanding at January 1, 2016
 
 
1,883
 
$
5.83
 
 
5.14
 
$
388
 
Granted
 
 
168
 
 
5.10
 
 
 
 
 
 
 
Exercised
 
 
 
 
 
 
 
 
 
 
 
Expired or cancelled
 
 
(17)
 
 
7.70
 
 
 
 
 
 
 
Forfeited
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Outstanding at March 31, 2016
 
 
2,034
 
$
5.75
 
 
6.38
 
$
642
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Exercisable at March 31, 2016
 
 
1,532
 
$
5.97
 
 
5.27
 
$
642