Share-based compensation
The following table shows the total share-based compensation expense recorded in the Consolidated Statements of Operations and Comprehensive Loss (in thousands):
| | | | | | | | | | | | | | | | | |
| 2025 | | 2024 | | 2023 |
Research and development | $ | 8,776 | | | $ | 7,771 | | | $ | 6,467 | |
Selling, general and administrative | $ | 28,922 | | | $ | 26,419 | | | $ | 26,002 | |
Equity Incentive Plan
Under the Company’s Equity Incentive Plan ("EIP"), the Company may grant market value options, share appreciation rights or restricted shares, restricted share units ("RSUs"), performance share units and other share-based awards to the Company’s employees. The Company’s board members and consultants are eligible to receive awards under the Company’s non-employee sub-plan to the EIP. Awards may be granted at such times as the Company may determine, but will generally be granted annually following the end of the financial year. Awards vest at such times and as specified in the award agreement, typically being over a four-year period although the Company retains the discretion to provide for other vesting schedules. If the participant violates the non-competition, non-solicitation, confidentiality or other similar restrictive covenant provisions of any employment contract, the right of the participant to receive these shares on vesting shall terminate immediately. The Company maintains discretion over the type and terms of equity awards granted. Share options lapse on the tenth anniversary from the date of grant, and they are not subject to performance conditions or entitled to dividends. As of December 31, 2025, the Company has reserved 6,172,915 authorized shares for future issuance under the EIP.
During the years ended December 31, 2025 and 2024, options over a total of 1,793,514 shares and 1,062,745 shares respectively were awarded under the Company’s EIP. Of the above awards in the year ended December 31, 2025, there were 207,829 options awarded to the Company's non-executive directors, 183,386 of which vest on the first anniversary from the date of grant and 24,443 of which vest monthly over a three-year period. In fiscal year 2024, there were 85,595 non-executive options awarded, 72,670 of which vested on the first anniversary from the date of grant and 12,925 of which vest monthly over a three-year period.
Share option activity
The number and weighted average exercise prices of share options were as follows:
| | | | | | | | | | | | | | | | | | | | | | | |
Number of shares issuable | Number of Share Options | | Weighted Average Exercise Price | | Weighted Average Remaining Contractual Term | | Aggregate Intrinsic Value (in thousands) |
| Outstanding as of December 31, 2024 | 9,422,875 | | $ | 31.14 | | | 6.0 years | | $ | 50,455 | |
| Awards granted | 1,793,514 | | 29.66 | | | | | |
| Awards exercised | (624,411) | | 19.82 | | | | | |
Awards forfeited | (131,347) | | 40.01 | | | | | |
Awards expired | (86,315) | | 45.16 | | | | | |
| Outstanding as of December 31, 2025 | 10,374,316 | | $ | 31.34 | | | 5.9 years | | $ | 87,338 | |
| Exercisable at December 31, 2025 | 7,857,031 | | $ | 28.59 | | | 5.0 years | | $ | 77,958 | |
The weighted average fair value of options granted in 2025 was $16.05 (2024: $37.71; 2023: $38.57). The weighted average share price at the date of exercise of the options during the year was $33.47 (2024: $63.70; 2023: $56.73).
In the years ended December 31, 2025, 2024 and 2023, the total intrinsic value of stock options exercised was $8.8 million, $14.4 million and $58.4 million, respectively. The tax benefit arising on the exercise of stock options was $0.8 million, $2.2 million and $3.1 million for the years ended December 31, 2025, 2024 and 2023, respectively.
As of December 31, 2025, total unrecognized compensation expense related to share options granted but not vested was $18.7 million, which the Company expects to recognize over a remaining weighted-average period of 1.5 years.
Awards granted in the year ended December 31, 2025, 2024 and 2023, have been valued using the Black-Scholes option pricing model. The assumptions used in the models for share options granted during the years ended December 31, 2025, 2024 and 2023, were as follows:
| | | | | | | | | | | | | | | | | |
| 2025 | | 2024 | | 2023 |
| Share price at grant date | $28.63 - $35.93 | | $31.13 - $70.50 | | $46.48 - $64.53 |
| Exercise price | $28.63 - $35.93 | | $31.13 - $70.50 | | $46.48 - $64.53 |
| Expected volatility | 52.11% - 55.78% | | 54.98% - 66.17% | | 66.70% - 72.05% |
Expected life | 5.5 years | | 5 years - 5.5 years | | 5 years |
| Risk free rate | 3.73% - 4.41% | | 3.53% - 4.56% | | 3.52% - 4.75% |
| Fair value | $15.11 - $18.47 | | $16.53 - $40.47 | | $27.77 - $39.02 |
Restricted share unit activity
In February 2025, the Company granted RSU awards that vest over a four-year service period with 25% on each anniversary of the grant date. An RSU award represents the right to receive one of the Company’s ADSs upon vesting of the RSU. The fair value of each RSU award is based on the closing price of the Company’s ADSs on Nasdaq on the date of grant.
The number and weighted average fair value of RSUs were as follows:
| | | | | | | | | | | |
| Number of RSUs | | Weighted Average Grant Date Fair Value |
| Unvested and outstanding as of December 31, 2024 | — | | $ | — | |
| Awards granted | 521,072 | | 29.87 |
| Awards vested | — | | — |
| Awards forfeited | (24,916) | | 29.70 |
Unvested and outstanding as of December 31, 2025 | 496,156 | | $ | 29.88 | |
As of December 31, 2025, total unrecognized compensation expense related to RSUs granted but not vested was $7.4 million, which the Company expects to recognize over a remaining weighted-average period of 2.1 years.