Stock-based Compensation (Tables)
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9 Months Ended |
Sep. 30, 2015 |
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| Disclosure Of Compensation Related Costs Sharebased Payments [Abstract] |
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| Weighted average assumptions |
The fair value of the stock options granted during the three and nine months ended September 30, 2015 and 2014, was estimated based on the following weighted average assumptions:
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Three Months Ended September 30,
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Nine Months Ended September 30,
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2015
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2014
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2015
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|
2014
|
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Dividend yield
|
|
|
0
|
%
|
|
|
0
|
%
|
|
|
0
|
%
|
|
|
0
|
%
|
|
Expected volatility
|
|
|
103
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%
|
|
|
88
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%
|
|
|
83
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%
|
|
|
93
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%
|
|
Risk-free interest rate
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|
|
1.36
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%
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|
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1.79
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%
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|
|
1.40
|
%
|
|
|
1.72
|
%
|
|
Expected term
|
|
5.6 years
|
|
|
5.6 years
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|
5.6 years
|
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|
5.6 years
|
|
|
| Stock option activity |
Stock option activity for the nine months ended September 30, 2015, was as follows:
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Options
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Weighted
Average Exercise Price Per Share
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Weighted
Average
Remaining Contractual
Life
(in years)
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Aggregate
Intrinsic Value
(in thousands)
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Outstanding at January 1, 2015
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7,702,309
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|
$
|
8.15
|
|
|
|
|
|
|
|
|
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Granted
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1,790,722
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|
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3.79
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Exercised
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(163,663
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)
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|
1.89
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|
|
|
|
|
|
|
|
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Forfeited, expired or cancelled
|
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(1,156,878
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)
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|
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15.96
|
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|
|
|
|
|
|
|
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Outstanding at September 30, 2015
|
|
|
8,172,490
|
|
|
$
|
6.22
|
|
|
|
6.54
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|
|
$
|
—
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Vested and expected to vest at September 30, 2015
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7,891,195
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$
|
6.27
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6.48
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|
$
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—
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Exercisable at September 30, 2015
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5,399,778
|
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$
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7.04
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|
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5.71
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|
|
$
|
—
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| Unvested RSU activity |
Unvested RSU activity for the nine months ended September 30, 2015, is summarized below:
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Weighted-
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Number of
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Average Grant-
|
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Shares
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Date Fair Value
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Unvested balance at January 1, 2015
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$
|
1,953,879
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$
|
5.46
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Granted
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1,694,932
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|
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3.82
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Vested
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(1,027,497
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)
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4.66
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Forfeited
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(348,960
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)
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4.51
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Unvested balance at September 30, 2015
|
|
$
|
2,272,354
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|
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4.74
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|
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| Stock-based compensation expense |
The following table shows total stock-based compensation expense for stock options, RSUs and ESPP in the condensed consolidated statements of comprehensive loss for the three and nine months ended September 30, 2015 and 2014 (in thousands):
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Three Months Ended September 30,
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Nine Months Ended September 30,
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2015
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|
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2014
|
|
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2015
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|
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2014
|
|
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Research and development
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$
|
1,047
|
|
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$
|
1,765
|
|
|
$
|
4,642
|
|
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$
|
5,124
|
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Selling, general and administrative
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|
917
|
|
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|
1,772
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3,676
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|
4,761
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|
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Total stock-based compensation expense
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|
$
|
1,964
|
|
|
$
|
3,537
|
|
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$
|
8,318
|
|
|
$
|
9,885
|
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