Stock-Based Compensation (Tables)
|
9 Months Ended |
Sep. 30, 2017 |
Share-based Compensation [Abstract] |
|
Summary of Fair Value Assumptions for Stock Options |
The following table summarizes the Company’s grant date fair value and assumptions used in determining the fair value of all stock options granted:
| | | | | | | | | | Three Months Ended September 30, | | Nine Months Ended September 30, | | 2017 | | 2016 | | 2017 | | 2016 | Volatility | 72%-73% | | 75%-76% | | 72%-74% | | 75%-77%
| Risk-free interest rate | 1.73%-1.93% | | 1.00%-1.18%
| | 1.73%-1.99% | | 1.00%-1.73%
| Dividend yield | 0.0% | | 0.0% | | 0.0% | | 0.0% | Expected option term (in years) | 6.25 | | 6.25 | | 6.25 | | 6.25 | Weighted average fair value of stock options granted | $9.59 | | $7.79 | | $10.18 | | $8.74 |
|
Summary of Stock Option Activity |
The following table summarizes the Company’s aggregate stock option activity for the nine months ended September 30, 2017: | | | | | | | | | | | | | | | Number of Shares | | Weighted Average Exercise Price | | Weighted Average Remaining Contractual Life in Years | | Aggregate Intrinsic Value (in thousands) | Options outstanding at December 31, 2016 | 7,116,706 |
| | $ | 13.30 |
| | | | |
| Granted | 2,207,390 |
| | $ | 15.42 |
| | | | |
| Exercised | (336,135 | ) | | $ | 8.78 |
| | | | |
| Forfeited or expired | (386,668 | ) | | $ | 15.59 |
| | | | |
| Options outstanding at September 30, 2017 | 8,601,293 |
| | $ | 13.92 |
| | 7.65 | | $ | 148,771 |
| Vested and expected to vest at September 30, 2017 | 8,269,230 |
| | $ | 13.88 |
| | 7.60 | | $ | 143,327 |
| Exercisable at September 30, 2017 | 3,904,073 |
| | $ | 12.46 |
| | 6.40 | | $ | 73,193 |
|
|
Summary of Exercise Price and Number of Stock Options Exercisable |
The following table summarizes the range of exercise prices and the number of stock options outstanding and exercisable: | | | | | | | | | | | | | | | | | | | | Outstanding as of September 30, 2017 | | Exercisable as of September 30, 2017 | Range of Exercise Prices ($) | | Number of Options | | Weighted Average Remaining Contractual Term (in years) | | Weighted Average Exercise Price ($) | | Number of Options | | Weighted Average Exercise Price ($) | 3.03 |
| | 4.55 |
| | 988,195 |
| | 4.89 | | 3.59 |
| | 988,195 |
| | 3.59 |
| 6.90 |
| | 6.90 |
| | 137,577 |
| | 5.47 | | 6.90 |
| | 100,077 |
| | 6.90 |
| 6.96 |
| | 10.85 |
| | 1,081,121 |
| | 8.55 | | 10.76 |
| | 289,330 |
| | 10.52 |
| 11.14 |
| | 12.58 |
| | 1,095,757 |
| | 6.65 | | 12.17 |
| | 735,792 |
| | 12.16 |
| 12.66 |
| | 13.58 |
| | 185,880 |
| | 7.76 | | 13.24 |
| | 89,704 |
| | 13.29 |
| 13.67 |
| | 13.67 |
| | 865,660 |
| | 9.27 | | 13.67 |
| | — |
| | — |
| 13.94 |
| | 15.91 |
| | 862,300 |
| | 8.01 | | 14.97 |
| | 339,372 |
| | 14.55 |
| 16.07 |
| | 16.16 |
| | 1,009,781 |
| | 7.93 | | 16.13 |
| | 463,410 |
| | 16.12 |
| 16.19 |
| | 17.16 |
| | 871,266 |
| | 9.34 | | 17.10 |
| | 31,741 |
| | 16.30 |
| 17.24 |
| | 27.38 |
| | 1,503,756 |
| | 7.41 | | 21.20 |
| | 866,452 |
| | 21.13 |
|
|
Summary of RSU Activity |
The following table summarizes the Company’s RSU award activity during the nine months ended September 30, 2017: | | | | | | | | Number of RSUs | | Weighted Average Grant Price ($) | Outstanding at December 31, 2016 | 89,194 |
| | 10.85 |
| Granted | 46,914 |
| | 17.16 |
| Released | (89,194 | ) | | (10.85 | ) | Outstanding at September 30, 2017 | 46,914 |
| | 17.16 |
|
|
Summary of Allocation of Employee Stock-Based Compensation |
The following table summarizes the aggregate stock-based compensation recorded in the Consolidated Statements of Comprehensive Loss related to stock options and RSUs during the three and nine months ended September 30, 2017 and 2016: | | | | | | | | | | | | | | | | | | Three Months Ended September 30, | | Nine Months Ended September 30, | | 2017 | | 2016 | | 2017 | | 2016 | | (in millions) | Research and development expenses | $ | 1.8 |
| | $ | 1.7 |
| | $ | 4.8 |
| | $ | 4.6 |
| General and administrative expenses | 2.9 |
| | 3.4 |
| | 8.5 |
| | 9.3 |
| Total | $ | 4.7 |
| | $ | 5.1 |
| | $ | 13.3 |
| | $ | 13.9 |
|
|