The Company’s equity incentive plans, the 2018 Long Term Incentive Plan, as amended (the “2018 LTIP”), 2020 Employment Inducement Incentive Plan, as amended (the “2020 EIIP”), and previously, the Amended and Restated 2012 Long Term Incentive Plan (the “2012 LTIP”), reserve ordinary shares for the issuance of stock options, stock appreciation rights, restricted shares, RSUs, performance bonus awards, performance share units awards, dividend equivalents and other share or cash-based awards to eligible individuals. Options granted under each of the 2018 LTIP, 2020 EIIP, and 2012 LTIP expire no later than ten years from the date of grant.

As of June 30, 2026, the number of ordinary shares authorized under the 2018 LTIP was 18,641,433. Upon adoption of the 2018 LTIP, no new awards are permitted under the 2012 LTIP.

As of June 30, 2026, the number of ordinary shares authorized under the 2020 EIIP was 1,485,000 and 696,163 ordinary shares remained available for future awards under the 2020 EIIP. The Company’s Board of Directors has adopted a series of amendments to increase the ordinary shares available for issuance under the 2020 EIIP and it reserves the right to both amend the 2020 EIIP to increase the number of ordinary shares available and make additional awards to key new hires.

The Company’s option awards generally vest over four years, while RSU awards generally vest over either two or three years. As of June 30, 2026, 3,196,732 ordinary shares remained available for grant under the Company’s equity incentive plans.

Share-based compensation expense recorded in these Condensed Consolidated Financial Statements was based on awards granted under the 2012 LTIP, the 2018 LTIP, and the 2020 EIIP. The estimated forfeiture rate as of June 30, 2026 was 11%. Changes in our estimates and assumptions relating to forfeitures may cause us to realize changes in stock-based compensation expense in the future.

The amount of unearned share-based compensation related to unvested stock options at June 30, 2026, is $32.9 million. The weighted-average period over which this unearned share-based compensation is expected to be recognized is 2.96 years.


	Three Months Ended June 30,				Six Months Ended June 30,
	2026		2025		2026		2025
Research and development	$	1,668	$	4,674	$	3,661	$	9,519
General and administrative	4,467		5,663		9,389		11,767
Restructuring costs (1)	1,743		2,081		1,743		2,081
Total share-based compensation expense	$	7,878	$	12,418	$	14,793	$	23,367

(1)Restructuring costs for the three and six months ended June 30, 2026 and 2025 includes $1.7 million and $2.1 million of share-based compensation expense related to the contractual acceleration of vesting of certain option and restricted stock unit award agreements.

The Company recognized no tax benefits for the three and six months ended June 30, 2026 due to the Company’s full valuation allowance on its deferred tax assets. The Company recognized tax benefits from share-based awards of $2.4 million and $4.4 million for the three and six months ended June 30, 2025.

The fair value of the options granted to employees and non-employee directors during the three and six months ended June 30, 2026 and 2025 was estimated as of the grant date using the Black-Scholes option-pricing model using the key assumptions listed in the following table.


	Three Months Ended June 30,								Six Months Ended June 30,
	2026			2025					2026			2025
Expected volatility	71.9%	-	74.2%	77.7	%	-	79.0	%	71.9%	-	75.1%	76.5	%	-	79.0	%
Risk-free interest rate	4.0%	-	4.3%	3.8	%	-	4.2%		3.6%	-	4.3%	3.8	%	-	4.4%
Expected dividend yield	—%			—%					—%			—%
Expected term (in years)	4.29	-	5.98	4.81		-	5.76		4.22	-	5.98	4.78		-	5.76
Weighted average grant date fair value	$6.85			$4.77					$6.29			$9.49

The fair value of employee stock options is amortized on a straight-line basis over the requisite service period for each award. Each of the inputs discussed above is subjective and generally requires management judgment to determine.


	Options	Weighted Average Exercise Price		Weighted Average Remaining Contractual Term (years)	Aggregate Intrinsic Value (in thousands)
Outstanding at December 31, 2025	10,289,294	$	24.18	5.03	$	402
Granted	2,285,900	9.46
Exercised	—	—
Forfeited	(268,101)	16.43
Expired	(544,908)	25.91
Outstanding at June 30, 2026	11,762,185	$	21.42	5.34	$	1,239
Vested and expected to vest at June 30, 2026	11,214,351	$	21.84	5.15	$	1,095
Exercisable at June 30, 2026	8,265,940	$	24.12	3.76	$	466


	Number of Units	Weighted Average Grant-Date Fair Value		Weighted Average Remaining Contractual Term (years)	Aggregate Intrinsic Value (in thousands)
Unvested at December 31, 2025	1,090,778	$	7.63	1.08	$	10,417
Units Granted	511,308	9.37
Units Vested	(155,233)	8.61
Units Forfeited	(23,923)	14.95
Unvested at June 30, 2026	1,422,930	$	8.02	1.01	$	13,930
Unvested and expected to vest at June 30, 2026	1,271,183	$	7.94	0.92	$	12,445

As of June 30, 2026, total compensation cost not yet recognized related to unvested RSUs was $7.5 million, which is expected to be recognized over a weighted-average period of 2.30 years. RSUs settle into ordinary shares upon vesting.