Stockholders' Equity (Tables)
|
12 Months Ended |
Dec. 31, 2015 |
|---|
| Summary of Stock Options Activity |
The activity for stock options under the Company’s stock plans is as follows:
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Remaining
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weighted-
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Weighted-
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average
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Per share
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average
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contractual
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average
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Price per
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exercise
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terms
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intrinsic
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Options
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share
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price
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(in years)
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value
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Outstanding as of December 31, 2012
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1,646,223
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$0.60-$8.70
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$
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1.06
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6.99
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$
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0.41
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Granted
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716,326
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1.17-8.37
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3.95
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Exercised
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(8,874
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)
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0.60-8.70
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1.35
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Forfeited
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(23,106
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)
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0.60-8.37
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2.46
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Expired
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(1,894
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)
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0.60-8.70
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1.53
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Outstanding as of December 31, 2013
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2,328,675
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0.60-8.70
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1.94
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7.04
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10.23
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Vested and exercisable at December 31, 2013
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1,524,325
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0.60-8.70
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1.16
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5.95
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11.01
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Vested and expected to vest, at December 31, 2013
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2,226,738
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0.60-8.70
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1.88
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6.95
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10.29
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Outstanding as of December 31, 2013
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2,328,675
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0.60-8.70
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1.94
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7.04
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10.23
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Granted
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754,916
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16.62-24.52
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17.81
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Exercised
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(736,519
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)
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0.60-16.62
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1.28
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Forfeited
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(80,640
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)
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0.60-16.62
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5.81
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Expired
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(4,799
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)
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0.60-8.37
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1.09
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Outstanding as of December 31, 2014
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2,261,633
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0.60-24.52
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7.31
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6.43
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24.06
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Vested and exercisable at December 31, 2014
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1,100,539
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0.60-18.93
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2.02
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5.73
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29.35
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Vested and expected to vest, at December 31, 2014
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2,144,974
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0.60-24.52
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7.19
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6.38
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24.18
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Outstanding as of December 31, 2014
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2,261,633
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0.60-24.52
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7.31
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6.43
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24.06
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Granted
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759,301
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37.10-46.66
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39.91
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Exercised
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(676,715
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)
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0.60-24.52
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2.39
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Forfeited
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(48,849
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)
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0.75-38.54
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16.28
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Expired
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—
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—
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—
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Outstanding as of December 31, 2015
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2,295,370
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0.60-46.66
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19.36
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5.98
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21.07
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Vested and exercisable at December 31, 2015
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933,707
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0.60-46.66
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7.16
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5.55
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32.97
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Vested and expected to vest, at December 31, 2015
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2,179,294
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$0.60-$46.66
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$
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19.15
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5.96
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$
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21.27
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| Summary of ESPP Activity |
The activity for the ESPP was as follows for the offering periods March 1, 2014 through December 31, 2015:
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First Offering
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Second Offering
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Third Offering
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Fourth Offering
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(amounts in thousands, except share and per share amounts)
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Period
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Period
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Period
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Period*
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Employee accumulated payroll deductions
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$
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414
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$
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343
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$
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361
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$
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388
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Total shares purchased
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30,358
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18,551
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12,555
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—
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Payroll deductions used to purchase shares
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$
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413
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$
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342
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$
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359
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$
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—
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Transfer to next offering period
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$
|
1
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$
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1
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$
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3
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$
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—
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FMV at enrollment date per share
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$
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16.00
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$
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21.69
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$
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33.62
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$
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49.25
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FMV at purchase date per share
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$
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21.69
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$
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33.62
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$
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49.25
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$
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—
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Purchase price per share
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$
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13.60
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$
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18.44
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$
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28.58
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$
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—
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*Offering period ends March 1, 2016
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| Assumptions Used to Estimate Fair Value of Employee Options |
The value of employee options was estimated on the date of grant using the Black-Scholes option pricing model with the following assumptions used:
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2015
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2014
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2013
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Expected term (years)
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3.50-5.48
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4.02-6.99
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5.26-6.03
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Risk free interest rate
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0.95-1.77%
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1.32-2.02%
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1.08-1.76%
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Expected dividend yield
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None
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None
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None
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Volatility
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41.99-44.87%
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42.15-52.73%
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50.10-52.77%
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| Summary of Outstanding Warrants |
A summary of outstanding warrants at December 31, 2014 is as follows:
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Number of
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Exercise
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Expiration
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Security
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warrants
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price/share
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|
date
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Common stock
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15,218
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|
$
|
0.30
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|
2017-2019
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| Reconciliation of Warrant Activity |
A reconciliation of warrant activity from January 1, 2014 to December 31, 2015 is as follows:
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Issued and
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Issued and
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outstanding
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outstanding
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warrants as of
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Warrants
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Warrants
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warrants as of
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|
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January 1, 2015
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exercised
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expired
|
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|
December 31, 2015
|
|
|
Common stock
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|
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15,218
|
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|
|
15,218
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|
—
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—
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Issued and
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Issued and
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outstanding
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outstanding
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warrants as of
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Warrants
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Warrants
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warrants as of
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|
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January 1, 2014
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exercised
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expired
|
|
|
December 31, 2014
|
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Series C preferred
|
|
|
14,215
|
|
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|
11,459
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2,756
|
|
|
|
—
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|
Series D preferred
|
|
|
11,415
|
|
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|
11,415
|
|
|
|
—
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|
|
—
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Series E preferred
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|
4,222
|
|
|
|
4,222
|
|
|
|
—
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|
|
—
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Common stock
|
|
|
233,611
|
|
|
|
218,393
|
|
|
|
—
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|
15,218
|
|
|
|
|
|
263,463
|
|
|
|
245,489
|
|
|
|
2,756
|
|
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|
15,218
|
|
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| Redeemable Convertible Preferred Stock |
|
| Summary of Convertible Preferred Stock |
A summary of the terms of the various types of redeemable convertible preferred stock at December 31, 2013, is as follows:
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Series
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B
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C
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D
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E
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F
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G
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Total
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Shares authorized
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500,000
|
|
|
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400,000
|
|
|
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1,700,000
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|
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|
1,700,000
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2,800,000
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|
|
2,900,000
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|
|
10,000,000
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|
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Shares issued
|
|
|
425,511
|
|
|
|
365,903
|
|
|
|
1,573,126
|
|
|
|
1,634,874
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|
|
|
2,701,957
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|
|
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2,840,260
|
|
|
|
9,541,631
|
|
|
Par value
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$
|
0.001
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|
|
$
|
0.001
|
|
|
$
|
0.001
|
|
|
$
|
0.001
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|
$
|
0.001
|
|
|
$
|
0.001
|
|
|
|
|
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Conversion rate
|
|
|
1.45108
|
|
|
|
1.73014
|
|
|
|
1.87951
|
|
|
|
2.69244
|
|
|
|
1.00000
|
|
|
|
1.00000
|
|
|
|
|
|
|
Liquidation preference per
share
|
|
$
|
11.880
|
|
|
$
|
17.580
|
|
|
$
|
21.900
|
|
|
$
|
19.224
|
|
|
$
|
7.140
|
|
|
$
|
14.083
|
|
|
|
|
|
|
Dividend rate
|
|
|
5
|
%
|
|
|
8
|
%
|
|
|
8
|
%
|
|
|
8
|
%
|
|
|
8
|
%
|
|
|
8
|
%
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
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|
|
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|
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|
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|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
July
|
|
|
October
|
|
|
February
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
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|
June
|
|
|
2005 to
|
|
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2007 to
|
|
|
2010 to
|
|
|
March
|
|
|
|
|
|
|
Issue date
|
|
July 2003
|
|
|
2004
|
|
|
July 2007
|
|
|
February 2009
|
|
|
June 2010
|
|
|
2012
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
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|
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|
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|
|
|
Redemption date
|
|
January 1,
|
|
|
January 1,
|
|
|
January 1,
|
|
|
January 1,
|
|
|
January 1,
|
|
|
January 1,
|
|
|
|
|
|
|
|
|
2016
|
|
|
2016
|
|
|
2016
|
|
|
2016
|
|
|
2016
|
|
|
2016
|
|
|
|
|
|
|
| Nonredeemable Convertible Preferred Stock |
|
| Summary of Convertible Preferred Stock |
A summary of the terms of non-redeemable convertible preferred stock at December 31, 2013 is as follows:
|
Series A
|
|
|
|
|
|
Shares authorized
|
|
|
100,000
|
|
|
Share issued
|
|
|
66,666
|
|
|
Par value
|
|
$
|
0.001
|
|
|
Conversion rate
|
|
|
1.01706
|
|
|
Liquidation preference per share
|
|
$
|
3.750
|
|
|
Dividend rate
|
|
|
5
|
%
|
|
Issue date
|
|
May 2002
|
|
|