Annual report pursuant to Section 13 and 15(d)

Stock Plans (Tables)

v3.19.1
Stock Plans (Tables)
 12 Months Ended
Dec. 31, 2018
Share-based Compensation [Abstract]  
Share-based Compensation, Stock Options, Activity [Table Text Block]
Activity under our stock plans, as well as non-plan activity, is summarized below (shares in thousands):
 
 
 
Shares or

Awards  Available

For Grant
 
 
Number of

Options and

Awards

Outstanding
 
 
Weighted Average

Exercise Price
 
Balance at December 31, 2015
 
 
152
 
 
 
314
 
 
$
34.98
 
Increase in shares reserved
 
 
190
 
 
 
—
 
 
 
—
 
Options granted
 
 
(28
)
 
 
28
 
 
$
30.60
 
Options exercised
 
 
—
 
 
 
(1
)
 
$
20.22
 
Options expired
 
 
—
 
 
 
(7
)
 
$
65.10
 
Balance at December 31, 2016
 
 
314
 
 
 
334
 
 
$
34.02
 
Options granted
 
 
(158
)
 
 
158
 
 
$
15.30
 
Options cancelled
 
 
10
 
 
 
(19
)
 
$
31.62
 
Options expired
 
 
—
 
 
 
(18
)
 
$
78.66
 
Balance at December 31, 2017
 
 
166
 
 
 
455
 
 
$
25.91
 
Increase in shares reserved
 
 
167
 
 
 
—
 
 
 
—
 
Options granted
 
 
(245
)
 
 
245
 
 
 
4.23
 
Options cancelled
 
 
16
 
 
 
(32
)
 
 
23.31
 
Options expired
 
 
—
 
 
 
(3
)
 
 
50.16
 
Balance at December 31, 2018
 
 
104
 
 
 
665
 
 
$
17.94
 
Schedule of Share-based Compensation, Shares Authorized under Stock Option Plans, by Exercise Price Range [Table Text Block]
Options to purchase approximately 0.6 million shares were exercisable at December 31, 2018 and 2017. The options outstanding at December 31, 2018 have been segregated into five ranges for additional disclosure as follows (options in thousands):
 
 
 
Options Outstanding
 
 
Options Exercisable
 
Range of Exercise

Prices
 
Number

Outstanding
 
 
Weighted

Average

Remaining

Life (Years)
 
 
Weighted

Average

Exercise Price
 
 
Number

Exercisable
 
 
Weighted

Average

Exercise Price
 
$1.26 - $5.46
 
 
87
 
 
 
9.78
 
 
$
1.38
 
 
 
3
 
 
$
1.97
 
$5.52 - $6.66
 
 
154
 
 
 
9.18
 
 
$
5.82
 
 
 
154
 
 
$
5.82
 
$6.72 - $23.10
 
 
125
 
 
 
5.22
 
 
$
12.68
 
 
 
125
 
 
$
12.68
 
$23.16 - $28.32
 
 
125
 
 
 
4.15
 
 
$
24.76
 
 
 
120
 
 
$
24.82
 
$28.38 - $77.88
 
 
174
 
 
 
4.85
 
 
$
35.88
 
 
 
174
 
 
$
35.88
 
$1.26 - $77.88
 
 
665
 
 
 
6.44
 
 
$
17.94
 
 
 
576
 
 
$
20.34
 
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 years ended December 31, 2018, 2017 and 2016:
 
 
 
Years Ended December 31,
 
 
 
2018
 
 
2017
 
 
2016
 
Weighted-average risk-free interest rate
 
 
2.84
%
 
 
2.13
%
 
 
1.53
%
Expected dividend payments
 
 
—
 
 
 
—
 
 
 
—
 
Expected holding period (years)(1)
 
 
6.39
 
 
 
5.90
 
 
 
6.53
 
Weighted-average volatility factor(2)
 
 
0.88
 
 
 
0.90
 
 
 
0.92
 
Estimated forfeiture rates for options granted
 
 
26
%
 
 
27
%
 
 
29
%
 
(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 Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Table Text Block]
The following table summarizes the stock-based compensation expense and impact on our basic and diluted loss per share for the years ended December 31, 2018, 2017 and 2016:
 
 
 
Years Ended December 31,
 
(in thousands, except per share amounts)
 
2018
 
 
2017
 
 
2016
 
Research and development
 
$
575
 
 
$
519
 
 
$
386
 
General and administrative
 
 
982
 
 
 
1,168
 
 
 
653
 
Total stock-based compensation expenses
 
$
1,557
 
 
$
1,687
 
 
$
1,039
 
Increase in basic net income (loss) per share
 
$
(0.27
)
 
$
(0.08
)
 
$
(0.05
)
Increase in diluted net income (loss) per share
 
$
(0.27
)
 
$
(0.08
)
 
$
(0.05
)
Schedule of Share-based Compensation, Restricted Stock Units Award Activity [Table Text Block]
The following table summarizes option activity for the year ended December 31, 2018:
 
(in thousands, except per share

amounts)
 
Shares
 
 
Weighted

Average

Exercise

Price
 
 
Weighted

Average

Remaining

Contractual

Term
 
 
Aggregate

Intrinsic

Value
 
Outstanding at January 1, 2018
 
 
455
 
 
$
25.91
 
 
 
5.75
 
 
$
30
 
Granted
 
 
245
 
 
 
4.23
 
 
 
 
 
 
 
 
 
Cancelled
 
 
(32
)
 
 
23.31
 
 
 
 
 
 
 
 
 
Expired
 
 
(3
)
 
 
50.16
 
 
 
 
 
 
 
 
 
Outstanding at December 31, 2018
 
 
665
 
 
$
17.94
 
 
 
6.44
 
 
$
4
 
Exercisable at December 31, 2018
 
 
576
 
 
$
20.34
 
 
 
5.93
 
 
$
—