XML 53 R15.htm IDEA: XBRL DOCUMENT
v3.25.0.1

Share-based compensation | 12 Months Ended
--- | ---
Dec. 31, 2024
Share-based compensation |
Share-based compensation | 8. Share-based compensation Employee incentive pool 2024 Inducement Plan In July 2024, the Company’s board of directors approved the 2024 Inducement Plan. The 2024 Inducement Plan allows for the granting of nonqualified share options, RSUs, and other equity awards to persons not previously an employee or director of the Company, or following a bona fide period of non-employment, as an inducement material to such persons entering into employment with the Company. Share options granted under the 2024 Inducement Plan have a 10-year contractual life and generally vest over a four-year service period with 25% of the award vesting on the first anniversary of the vesting commencement date and the balance thereafter in 36 equal monthly installments. The Company initially reserved 1,500,000 of its ordinary shares, or the equivalent number of ADSs, for the issuance of awards under the 2024 Inducement Plan. As of December 31, 2024, there were 1,251,400 shares available for future issuance under the 2024 Inducement Plan. As of December 31, 2024, there were options to purchase 248,600 shares outstanding under the 2024 Inducement Plan. 2020 Equity Incentive Plan In June 2020, the Company’s shareholders first approved the 2020 Plan, under which the Company may grant market value options, market value stock appreciation rights or restricted shares, RSUs, performance RSUs and other share-based awards to the Company’s employees. The Company’s non-employee directors and consultants are eligible to receive awards under the 2020 Non-Employee Sub-Plan to the 2020 Plan. All awards under the 2020 Plan, including the 2020 Non-Employee Sub-Plan, will be set forth in award agreements, which will detail the terms and conditions of awards, including any applicable vesting and payment terms, change of control provisions and post-termination exercise limitations. In the event of a change of control of the Company, as defined in the 2020 Plan, any outstanding awards under the 2020 Plan will vest in full immediately prior to such change of control. The Company initially reserved up to 4,773,557 ordinary shares for future issuance under the 2020 Plan, including shares subject to options that were granted under the Company’s 2019 Share Option Plan (the “2019 Plan”) and that were granted pursuant to option contracts granted prior to the Company’s IPO, in each case that expire, terminate, are forfeited or otherwise not issued from time to time, if any. On June 27, 2022, the Company’s shareholders approved an amendment to the 2020 Plan (the “Amendment”) which increased the number of ordinary shares reserved for future issuance by 750,000 shares. Additionally, the number of ordinary shares reserved for issuance pursuant to the 2020 Plan will automatically increase on the first day of January of each year, initially commencing on January 1, 2021 and continuing up to and including January 1, 2032, in an amount equal to 5% of the total number of the Company’s ordinary shares outstanding on the last day of the preceding year, or a lesser number of shares determined by the Company’s board of directors. Pursuant to this evergreen provision, on January 1, 2024, the number of shares reserved for issuance under the 2020 Plan was increased by 1,886,294 shares. As of December 31, 2024, there were 463,374 shares available for issuance under the 2020 Plan. The number of shares reserved for issuance under the 2020 Plan was increased by 2,378,465 shares effective January 1, 2025. Share options granted under the 2020 Plan have a 10-year contractual life, and generally vest over either a three-year service period in three equal annual installments for new non-employee director grants, or a four-year service period with 25% of the award vesting on the first anniversary of the vesting commencement date and the balance thereafter in 36 equal monthly installments for employees and consultants. Certain options granted to the Company’s non-employee directors vest over a one-year service period in four equal quarterly installments. The Company grants RSUs to non-employee directors, consultants and certain employees under the 2020 Plan. Each RSU represents the right to receive one of the Company’s ordinary shares upon vesting. RSUs granted to employees and consultants vest over a four-year service period with 25% of the award vesting on the first anniversary of the vesting commencement date and the remaining RSUs vesting in 12 equal quarterly installments. Certain RSUs granted to the Company’s non-employee directors either vest over a three-year service period in three equal annual installments for new non-employee director grants or over a one-year service period in four equal quarterly installments. The Company may also, in its sole discretion, provide for deferred settlement of RSUs granted to the Company’s non-employee directors. As of December 31, 2024, there were options to purchase 6,211,123 shares and RSUs for 716,262 shares outstanding under the 2020 Plan. 2019 Share Option Plan In May 2019, the Company adopted the 2019 Plan, which became effective in conjunction with the IPO. As of December 31, 2024, there were 1,773,816 options to purchase ordinary shares outstanding under the 2019 Plan. In conjunction with the adoption of the 2020 Plan, all shares available for future issuance under the 2019 Plan as of June 29, 2020 became available for issuance under the 2020 Plan and the Company ceased making awards under the 2019 Plan. The 2020 Plan is the successor of the 2019 Plan. Share options previously issued under the 2019 Plan have a 10-year contractual life, and generally either vest monthly over a three-year service period, or over a four-year service period with 25% of the award vesting on the first anniversary of the commencement date and the balance thereafter in 36 equal monthly installments. Certain awards granted to the Company’s non-employee directors were fully vested on the date of grant. The exercise price of share options issued under the 2019 Plan is not less than the fair value of ordinary shares as of the date of grant. Employee Share Purchase Plan (“ESPP”) In May 2019, the Company adopted the ESPP, which became effective in conjunction with the IPO. The Company initially reserved 215,000 ordinary shares for future issuance under this plan. The ESPP provides that the number of shares reserved and available for issuance will automatically increase each January 1, beginning on January 1, 2020 and each January 1 thereafter through January 1, 2029, by the lower of (i) 1% of the outstanding number of ordinary shares on the immediately preceding December 31; (ii) 430,000 ordinary shares or (iii) such lesser number of shares as determined by the Compensation Committee. The number of shares reserved under the ESPP is subject to adjustment in the event of a split-up, share dividend or other change in the Company’s capitalization. As of December 31, 2024, the total number of shares available for issuance under the ESPP was 1,577,671 shares. The number of shares reserved for issuance under the ESPP was increased by 430,000 shares effective January 1, 2025. As of December 31, 2024, there have been no offering periods to employees under ESPP. Share-based compensation The Company recorded share-based compensation expense in the following expense categories of its consolidated statements of operations and comprehensive loss (in thousands):
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
​ |  | Year Ended
​ |  | December 31,
​ |  | 2024 |  | 2023 |  | 2022
Research and development expenses | ​ | $ | 19,424 | ​ | $ | 15,581 | ​ | $ | 10,394
General and administrative expenses | ​ |  | 18,657 | ​ |  | 16,896 | ​ |  | 16,385
​ | ​ | $ | 38,081 | ​ | $ | 32,477 | ​ | $ | 26,779
​ Share options The following table summarizes the Company’s option activity since December 31, 2023: ​
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | Number of | ​ | ​ | ​ | ​ | Weighted | ​ | ​ | ​
​ | ​ | Shares | ​ | Weighted | ​ | Average | ​ | Aggregate
​ | ​ | Underlying | ​ | Average | ​ | Contractual | ​ | Intrinsic
​ |  | Share Options |  | Exercise Price |  | Term |  | Value
​ | ​ | ​ | ​ | ​ | ​ | ​ | (in years) | ​ | (in thousands)
Outstanding as of December 31, 2023 |  | 7,469,527 | ​ | $ | 23.13 |  | 6.83 | ​ | $ | 21,920
Granted |  | 2,438,356 | ​ |  | 19.42 |  | — | ​ |  | —
Exercised |  | (554,596) | ​ |  | 13.57 |  | — | ​ |  | —
Forfeited |  | (604,561) | ​ |  | 27.37 |  | — | ​ |  | —
Outstanding as of December 31, 2024 |  | 8,748,726 | ​ | $ | 22.41 |  | 6.81 | ​ | $ | 9,559
Vested and expected to vest as of December 31, 2024 |  | 8,748,726 | ​ | $ | 22.41 | ​ | 6.81 | ​ | $ | 9,559
Options exercisable as of December 31, 2024 |  | 5,359,049 | ​ | $ | 21.65 |  | 5.60 | ​ | $ | 9,559
​ The weighted average grant-date fair value of share options granted during the years ended December 31, 2024, 2023 and 2022 was $13.52 per share, $19.36 per share and $31.45 per share, respectively. The aggregate intrinsic value of share options is calculated as the difference between the exercise price of the share options and the fair value of the Company’s ordinary shares. The aggregate intrinsic value of share options exercised during the years ended December 31, 2024, 2023 and 2022 was $5.1 million, $0.5 million and $1.5 million, respectively. For the years ended December 31, 2024, 2023 and 2022, the Company recorded share-based compensation expense for share options granted of $30.2 million, $27.0 million and $21.9 million, respectively. The following table presents, on a weighted average basis, the assumptions used in the Black-Scholes option-pricing model to determine the fair value of share options granted to employees and directors: ​
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | Year Ended |
​ | ​ | December 31, |
​ |  | 2024 |  | 2023 |  | 2022 |
Risk-free interest rate |  | 4.0 | % | 4.0 | % | 2.2 | %
Expected volatility |  | 77.0 | % | 82.9 | % | 82.5 | %
Expected dividend yield |  | — |  | — |  | — | ​
Expected term (in years) |  | 6.1 |  | 6.1 |  | 6.0 | ​
​ As of December 31, 2024, total unrecognized compensation expense related to the share options was $48.3 million, which is expected to be recognized over a weighted average period of 2.4 years. Restricted share units The following table summarizes the Company’s RSU activity under the 2020 Plan since December 31, 2023: ​
​ | ​ | ​ | ​ | ​ | ​
​ | ​ | Number of Shares | ​ | Weighted-Average
​ | ​ | Underlying RSUs | ​ | Grant Date Fair Value
Unvested at December 31, 2023 | ​ | 326,848 | ​ | $ | 37.40
Granted | ​ | 617,496 | ​ | ​ | 18.26
Vested and settled | ​ | (141,350) | ​ | ​ | 37.76
Vested and deferred(1) | ​ | (42,000) | ​ | ​ | 18.07
Forfeited | ​ | (86,732) | ​ | ​ | 22.15
Unvested outstanding at December 31, 2024 | ​ | 674,262 | ​ | ​ | 22.96
Vested but subject to deferred settlement at December 31, 2024(1) | ​ | 42,000 | ​ | ​ | 18.07
Outstanding at December 31, 2024 | ​ | 716,262 | ​ | $ | 22.67
(1) | The Company granted certain RSUs to the Company’s non-employee directors which provided for deferred settlement of the RSUs to a specified date following the first to occur of (i) the date of the director’s separation from service, (ii) the date of the director’s disability, (iii) the date of the director’s death or (iv) the date of a change in control event.
The fair value of RSUs that vested during the years ended December 31, 2024, 2023 and 2022 was $3.8 million, $3.0 million and $2.1 million, respectively. Total share-based compensation expense for RSUs granted for the years ended December 31, 2024, 2023 and 2022 was $7.9 million, $5.5 million and $4.9 million, respectively. As of December 31, 2024, the total unrecognized compensation expense related to RSUs was $11.4 million, which is expected to be recognized over a weighted-average period of 2.4 years.

X
- Definition The entire disclosure for share-based payment arrangement. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 718 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (a)(1) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480429/718-10-50-2 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 718 -Name Accounting Standards Codification -Publisher FASB -URI https://asc.fasb.org/718/tableOfContent Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 718 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480429/718-10-50-2 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Topic 718 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (h)(2) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480429/718-10-50-2 Reference 5: http://www.xbrl.org/2003/role/disclosureRef -Topic 718 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (h)(2)(i) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480429/718-10-50-2 Reference 6: http://www.xbrl.org/2003/role/disclosureRef -Topic 718 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (l) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480429/718-10-50-2 + Details
Name: | us-gaap_DisclosureOfCompensationRelatedCostsShareBasedPaymentsTextBlock
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- References No definition available. + Details
Name: | us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration