Stock-Based Compensation (Tables)
|
9 Months Ended |
Sep. 30, 2016 |
Summary of Stock-based Compensation Expense Recognized |
During the three and nine months ended September 30, 2016 and 2015, the Company recognized the following stock-based compensation expense:
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Three Months Ended September 30, |
|
Nine Months Ended September 30, |
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|
2016 |
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|
2015 |
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2016 |
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|
2015 |
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Stock-based compensation expense by type of award: |
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|
|
|
|
|
|
|
|
|
|
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|
|
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Stock options |
|
$ |
154,228 |
|
|
$ |
373,881 |
|
|
|
|
$ |
762,067 |
|
|
$ |
725,572 |
|
Restricted stock and restricted stock units |
|
|
158,931 |
|
|
|
227,712 |
|
|
|
|
|
644,979 |
|
|
|
1,348,432 |
|
Employee stock purchase plan |
|
|
7,794 |
|
|
|
— |
|
|
|
|
|
28,706 |
|
|
|
— |
|
Total stock-based compensation expense included
in expenses |
|
$ |
320,953 |
|
|
$ |
601,593 |
|
|
|
|
$ |
1,435,752 |
|
|
$ |
2,074,004 |
|
Stock-based compensation expense by line item: |
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|
|
|
|
|
|
|
|
|
|
|
|
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|
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Research and development expenses |
|
$ |
60,202 |
|
|
$ |
164,125 |
|
|
|
|
$ |
1,006,781 |
|
|
$ |
665,226 |
|
General and administrative expenses |
|
|
260,751 |
|
|
|
437,468 |
|
|
|
|
|
428,971 |
|
|
|
1,408,778 |
|
Total stock-based compensation expense included
in expenses |
|
$ |
320,953 |
|
|
$ |
601,593 |
|
|
|
|
$ |
1,435,752 |
|
|
$ |
2,074,004 |
|
|
Schedule of Unrecognized Stock-based Compensation Expense, Net of Estimated Forfeitures, by Type of Award and Weighted-average Recognition Period |
The following table sets forth the Company’s unrecognized stock-based compensation expense, net of estimated forfeitures, by type of award and the weighted-average period over which that expense is expected to be recognized:
|
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As of September 30, 2016 |
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|
|
Unrecognized
Expense,
Net of
Estimated
Forfeitures |
|
|
Weighted-
average
Recognition
Period
(in years) |
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|
|
|
|
|
|
|
|
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Type of award: |
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|
|
|
|
|
|
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Stock options |
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$ |
1,272,626 |
|
|
|
2.55 |
|
Restricted stock and restricted stock units |
|
$ |
1,354,388 |
|
|
|
1.93 |
|
|
Summary of Stock Option Activity |
The following table summarizes stock option activity during the nine months ended September 30, 2016:
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|
Shares Subject to Stock Options |
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|
Weighted-
Average
Exercise
Price |
|
|
Weighted-
Average
Remaining
Contractual
Term (in years) |
|
Options outstanding at December 31, 2015 |
|
|
365,394 |
|
|
$ |
8.48 |
|
|
|
|
|
Granted |
|
|
520,818 |
|
|
$ |
2.17 |
|
|
|
|
|
Exercised |
|
|
— |
|
|
$ |
— |
|
|
|
|
|
Cancelled |
|
|
(50,250 |
) |
|
$ |
4.34 |
|
|
|
|
|
Options outstanding at September 30, 2016 |
|
|
835,962 |
|
|
$ |
4.80 |
|
|
|
8.95 |
|
Options exercisable at September 30, 2016 |
|
|
291,824 |
|
|
$ |
6.30 |
|
|
|
8.46 |
|
|
Schedule of Weighted Average Assumptions using Black-Scholes Option Pricing Model |
The fair value of each employee option grant during the nine months ended September 30, 2016 was estimated on the date of grant using the Black-Scholes option pricing model with the following weighted average assumptions:
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Nine months ended September 30, 2016 |
|
Expected volatility |
|
|
81.77 |
% |
Expected term (in years) |
|
|
5.92 |
|
Risk-free interest rate |
|
|
1.51 |
% |
Expected dividend yield |
|
|
0 |
% |
|
Restricted stock [Member] |
|
Summary of Stock Activity |
The following table is a summary of restricted stock activity during the nine months ended September 30, 2016:
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Shares of Restricted Stock |
|
|
Weighted-
Average
Grant Date
Fair Value |
|
Unvested at December 31, 2015 |
|
|
667,963 |
|
|
$ |
3.73 |
|
Granted |
|
|
— |
|
|
$ |
— |
|
Vested |
|
|
(108,218 |
) |
|
$ |
7.48 |
|
Forfeited |
|
|
(69,554 |
) |
|
$ |
6.37 |
|
Repurchased |
|
|
— |
|
|
$ |
— |
|
Unvested at September 30, 2016 |
|
|
490,191 |
|
|
$ |
2.53 |
|
|
Restricted stock units [Member] |
|
Summary of Stock Activity |
The following table summarizes restricted stock unit activity during the nine months ended September 30, 2016:
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|
Shares Subject to Restricted Stock Units |
|
|
Weighted-
Average
Grant Date
Value |
|
Unvested at December 31, 2015 |
|
|
75,750 |
|
|
$ |
8.27 |
|
Granted |
|
|
— |
|
|
$ |
— |
|
Vested |
|
|
(18,937 |
) |
|
$ |
8.27 |
|
Forfeited |
|
|
— |
|
|
$ |
— |
|
Repurchased |
|
|
— |
|
|
$ |
— |
|
Unvested September 30, 2016 |
|
|
56,813 |
|
|
$ |
8.27 |
|
|