Equity Compensation (Tables)
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12 Months Ended |
Dec. 31, 2017 |
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| Equity Compensation |
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| Summary of stock option activity |
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Weighted
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Weighted
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Average
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Shares Subject
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Average
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Weighted
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Remaining
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to Options
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Grant Date
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Average
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Contractual
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Outstanding
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Fair Value
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Exercise Price
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Life (Years)
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Balance at December 31, 2014
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4,851,221
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$
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10.57
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Granted
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238,516
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$
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5.31
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10.52
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Exercised
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(285,387)
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4.87
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Expired
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(47,866)
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13.92
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Forfeited
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(183,812)
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14.76
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Balance at December 31, 2015
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4,572,672
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10.72
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Granted
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50,000
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4.63
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8.16
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Exercised
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(685,798)
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5.01
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Expired
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(76,907)
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14.96
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Forfeited
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(83,562)
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14.81
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Balance at December 31, 2016
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3,776,405
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11.55
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Exercised
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(1,617,659)
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10.48
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Expired
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(60,275)
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17.51
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Forfeited
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(28,669)
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16.70
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Balance at December 31, 2017
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2,069,802
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12.13
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Exercisable options at December 31, 2016
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3,048,020
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10.69
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5.4
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Vested and expected to vest at December 31, 2016
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3,733,643
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11.52
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5.8
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Exercisable options at December 31, 2017
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1,786,261
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11.93
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5.0
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Vested and expected to vest at December 31, 2017
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2,069,802
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12.13
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5.3
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| Summary of stock options outstanding and exercisable |
The following table summarizes information about stock options outstanding and exercisable at December 31, 2017:
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Options Outstanding
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Options Exercisable
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Weighted-
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Weighted-
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Weighted
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Average
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Average
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Average
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Number of
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Remaining
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Number of
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Remaining
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Exercise
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Underlying
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Contractual
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Underlying
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Contractual
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Range of Exercise Prices
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Price
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Shares
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Life (in years)
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Shares
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Life (in years)
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$
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4.78
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-
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7.28
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6.01
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703,312
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3.5
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693,299
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3.4
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$
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7.49
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-
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11.29
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10.01
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434,929
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5.5
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338,311
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5.1
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$
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11.72
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-
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17.66
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14.70
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483,862
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6.9
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335,285
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6.9
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$
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19.56
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-
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22.92
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21.02
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447,699
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6.1
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419,366
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6.1
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2,069,802
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1,786,261
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| Summary of aggregate intrinsic-value of options exercised, exercisable, and vested and expected to vest |
The following table summarizes the aggregate intrinsic‑value of options exercised, outstanding and exercisable (in thousands):
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For the Years Ended
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and as of December 31,
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2017
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2016
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2015
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Options Exercised
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$
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19,966
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$
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3,312
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$
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1,432
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Options Exercisable
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31,841
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6,089
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3,496
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Options Vested and Expected to Vest
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36,489
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6,280
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3,499
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| Schedule of assumptions used to estimate fair value of option awards |
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December 31,
|
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2016
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2015
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Expected volatility
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62
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%
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51
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-
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55
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%
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Expected dividends
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0
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%
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0
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%
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Expected terms (in years)
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6.1
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5.3
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-
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6.1
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Risk-free rate
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1.1
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%
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1.3
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-
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1.8
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%
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| Summary of restricted stock unit activity |
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Number of
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Weighted Average
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Shares
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Grant Date Fair Value
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Non-vested balance at December 31, 2014
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—
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Awarded
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433,000
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$
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8.18
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Forfeited
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(8,000)
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8.18
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Non-vested balance at December 31, 2015
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425,000
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8.18
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Awarded
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1,147,946
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7.40
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Vested
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(35,340)
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7.85
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Forfeited
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(141,219)
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7.66
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Non-vested balance at December 31, 2016
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1,396,387
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7.60
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Awarded
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783,060
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11.28
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Vested
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(823,620)
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7.62
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Forfeited
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(65,167)
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8.82
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Non-vested balance at December 31, 2017
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1,290,660
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9.75
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| Schedule of total stock-based compensation expense classified in Statements of Operations |
Total stock‑based compensation expense has been classified as follows in the accompanying Consolidated Statements of Operations (in thousands):
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Years Ended
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December 31,
|
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2017
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2016
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2015
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Cost of revenue
|
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$
|
251
|
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$
|
171
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$
|
174
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Research and development
|
|
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4,242
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3,256
|
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|
2,885
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Sales and marketing
|
|
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3,662
|
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2,273
|
|
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1,783
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General and administrative
|
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3,950
|
|
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2,670
|
|
|
2,192
|
|
|
Total stock-based compensation expense
|
|
$
|
12,105
|
|
$
|
8,370
|
|
$
|
7,034
|
|
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