Common Stock (Tables)
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12 Months Ended |
Dec. 31, 2016 |
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| Equity [Abstract] |
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| Schedule of Common Stock |
Gross proceeds of $24.0 million and underwriting discounts and commissions and offering expenses of $1.6 million were allocated as follows:
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Series B
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Pre-funded
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Series A
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Series B
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Common
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Common
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Common
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Common
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Stock
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Stock
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Stock
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Stock
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Warrants
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Warrants
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Warrants
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Units Issued
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5,559,866
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1,340,538
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2,779,933
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670,269
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Gross Proceeds (in thousands)
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$
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14,084
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$
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3,387
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$
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5,261
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$
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1,268
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Underwriting discount and offering expense (in thousands)
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$
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885
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$
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213
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$
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428
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$
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103
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| Summary of Fair Value of Option Awards |
The estimated fair value of stock options granted in the respective periods was determined using the Black-Scholes option pricing model using the following weighted average assumptions:
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2016
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2015
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2014
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Risk-free interest rates
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1.51
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%
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1.76
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%
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1.83
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%
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Expected dividend yield
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0
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%
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0
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%
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0
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%
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Expected life
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5.3 years
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5.8 years
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5.9 years
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Expected volatility
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72
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%
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63
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%
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82
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%
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| Summary of Share-Based Compensation Expense |
The results for the periods set forth below included stock-based compensation expense in the following expense categories of the consolidated statements of loss (in thousands):
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Years ended
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December 31,
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2016
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2015
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2014
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Research and development
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$
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803
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$
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1,111
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$
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1,893
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General and administrative
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846
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1,217
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1,967
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Total stock-based compensation
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$
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1,649
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$
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2,328
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$
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3,860
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| Summary of Stock Options Activity |
Stock option transactions and the number of stock options outstanding are summarized below:
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Number of
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Weighted
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Optioned
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Average
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Common
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Exercise
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Shares
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Price
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Balance, January 1, 2014
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1,007,491
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$
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11.39
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Granted
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382,097
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8.97
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Expired
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(12,169
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)
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18.93
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Exercised
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(10,000
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)
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3.00
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Forfeited
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(84,000
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)
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12.14
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Balance, December 31, 2014
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1,283,419
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$
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10.55
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Granted
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502,047
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1.91
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Expired
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(247,766
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)
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2.96
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Exercised
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(5,359
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)
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2.69
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Forfeited
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(53,120
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)
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14.37
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Balance, December 31, 2015
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1,479,221
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$
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8.78
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Granted
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1,635,250
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0.86
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Expired
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(994,059
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)
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1.00
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Exercised
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—
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—
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Forfeited
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(741,607
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)
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1.96
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Balance, December 31, 2016
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1,378,805
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$
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8.62
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| Summary of Stock Options Outstanding Regarding Number of Common Shares Issuable upon Exercise of Outstanding Options |
(1) Number of common shares issuable upon exercise of outstanding options:
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Weighted-
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Average
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Remaining
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Weighted-
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Contractual
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Average
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Life
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Exercise Prices
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Number of Options
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Exercise Price
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(in years)
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$1.00 - $1.54
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122,010
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$
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1.00
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9.36
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$1.55 - $1.88
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337,298
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1.86
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7.96
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$1.89 - $3.40
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118,874
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2.62
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6.98
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$3.41 - $11.70
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78,447
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7.70
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5.72
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$11.71 - $11.86
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185,105
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11.79
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6.66
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$11.87 - $11.99
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144,699
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11.95
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5.64
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$12.00- $13.08
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132,650
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12.88
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4.97
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$13.09 - $16.40
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135,576
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15.64
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3.54
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$16.41 - $21.67
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63,446
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17.74
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3.56
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$21.68 - $22.28
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60,700
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22.28
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2.67
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1,378,805
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$
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8.62
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6.30
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| Summary of Stock Options Outstanding Regarding Number of Common Shares Issuable upon Exercise of Vested Options |
(2) Number common shares issuable upon exercise of vested options:
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Weighted-
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Average
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Remaining
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Weighted-
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Contractual
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Average
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Life
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Exercise Prices
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Number of Options
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Exercise Price
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(in years)
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$1.00 - $1.54
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510
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$
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1.21
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0.42
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$1.55 - $1.88
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184,008
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1.86
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7.74
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$1.89 - $3.40
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90,275
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2.51
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6.76
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$3.41 - $11.70
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75,217
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7.69
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5.78
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$11.71 - $11.86
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140,269
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11.79
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6.58
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$11.87 - $11.99
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141,951
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11.95
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5.64
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$12.00- $13.08
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132,650
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12.88
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4.97
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$13.09 - $16.40
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135,503
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15.64
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3.54
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$16.41 - $21.67
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63,446
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17.74
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3.56
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$21.68 - $22.28
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60,700
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22.28
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2.67
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1,024,529
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$
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10.54
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5.58
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| Summary of Restricted Stock Unit Award Activity |
The following table summarizes our restricted stock unit award activity during the years ended December 31, 2016, 2015 and 2014:
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Weighted
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Number
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Average
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of
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Grant Date
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Shares
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Fair Value
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Balance, January 1, 2014
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356,589
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$
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12.06
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Granted
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814,800
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6.48
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Vested
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(199,887
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)
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7.00
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Forfeited or expired
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(291,301
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)
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10.93
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Balance, December 31, 2014
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680,201
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$
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7.34
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Granted
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249,775
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1.92
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Vested
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(269,401
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)
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8.08
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Forfeited or expired
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(19,816
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)
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7.27
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Balance, December 31, 2015
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640,759
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$
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4.92
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Granted
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—
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—
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Vested
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(217,296
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)
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5.23
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Forfeited or expired
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(170,242
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)
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5.07
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Balance, December 31, 2016
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253,221
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$
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4.56
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| Summary of Outstanding Warrants |
The following is a summary of outstanding warrants to purchase common stock at December 31, 2016:
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Total
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Outstanding
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Exercise
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and
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price per
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Exercisable
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Share
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Expiration Date
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(1) Series A Warrants issued in July 2014 financing
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2,779,933
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4.00
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July 2019
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(2) Series B Warrants issued in July 2014 financing
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670,269
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4.00
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July 2019
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(3) Series A-1 Warrants issued in April 2015 financing
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239,234
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2.40
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October 2020
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| Summary of Fair Value of Warrants Issued |
The estimated fair value of warrants issued and classified as liabilities is reassessed at each reporting date using the Black-Scholes option pricing model.
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As of
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December 31,
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Series A and Series B Warrant Valuation Assumptions
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2016
|
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2015
|
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Risk-free interest rates
|
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1.33
|
%
|
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1.42
|
%
|
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Expected dividend yield
|
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|
0
|
%
|
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|
0
|
%
|
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Expected life
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2.50 years
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3.50 years
|
|
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Expected volatility
|
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|
95
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%
|
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|
77
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%
|
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| Computation of Basic and Diluted Net Loss Attributable to Common Shareholders Per Share |
The following table presents the computation of basic and diluted net loss attributable to common stockholders per share (in thousands, except per share and share amounts):
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Years ended December 31,
|
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2016
|
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2015
|
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2014
|
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Numerator
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Net loss
|
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$
|
(20,129
|
)
|
|
$
|
(16,801
|
)
|
|
$
|
(26,240
|
)
|
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Denominator
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Weighted average number of common shares outstanding
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29,949,432
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26,147,344
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18,098,799
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Basic and diluted net loss per common share
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$
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(0.67
|
)
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$
|
(0.64
|
)
|
|
$
|
(1.45
|
)
|
|