License Agreements	6 Months Ended
Jun. 30, 2026
License Agreements [Abstract]
License Agreements	8. License agreements Trace License Agreement In March 2024, the Company entered into an exclusive license agreement with Trace Neuroscience, Inc., or Trace, pursuant to which the Company granted an exclusive worldwide license to a discovery research program targeting UNC13A for the treatment of amyotrophic lateral sclerosis, or the Trace License Agreement. As consideration for the licensed rights and the transfer of know-how and materials, the Company received an upfront payment of $15.0 million in April 2024. Thereafter, the Company is entitled to potential subsequent payments of up to an aggregate of $80.0 million based on development and regulatory milestones and up to an aggregate of $250.0 million based on sales milestones. The Company is also entitled to tiered royalties ranging from percentages in the low single-digits to sub-teens on net sales of any licensed product if successfully commercialized. The Company assessed the Trace License Agreement in accordance with ASC 606 and concluded that it was a contract with a customer. The Company determined that there is one performance obligation relating to the license to the UNC13A discovery program, including the underlying know-how and certain related materials, and that the transaction price consisted of the $15.0 million non-refundable upfront cash payment. The potential future development and regulatory milestones represent variable consideration and were constrained, as it was concluded that it was not probable that a significant reversal in cumulative revenue recognized will not occur and therefore not included in the transaction price as of June 30, 2026. Potential sales milestones and royalties on net product sales will be recognized in the same period that the underlying net product sales occur as they were determined to relate to the license. The $15.0 million transaction price was recorded as license revenue in the statements of operations and comprehensive loss during the year ended December 31, 2024, at the point in time when control of the license and related know-how was transferred to Trace. Shionogi License Agreement In March 2024, the Company entered into an exclusive license agreement with Shionogi & Company, Ltd., or Shionogi, pursuant to which the Company granted Shionogi an exclusive, worldwide, sublicensable license to research, develop, manufacture and commercialize MZE001 and certain other small molecule compounds modulating glycogen synthase 1, or the Shionogi License Agreement. As consideration for the licensed rights and the transfer of know-how and materials, the Company received an upfront payment of $150.0 million in May 2024 upon the effectiveness of the Shionogi License Agreement. The Shionogi License Agreement also requires that Shionogi pay the Company up to $275.0 million in the aggregate in milestone payments upon the completion of certain clinical and regulatory milestones and up to $330.0 million in the aggregate in milestone payments if certain sales milestones are achieved. In March 2026, a $20.0 million clinical development milestone was achieved upon dosing of the first patient in Shionogi's Phase 2 study of MZE001 in patients with Pompe disease. The Company recognized $20.0 million as license revenue in the condensed statements of operations and comprehensive loss for the three months ended March 31, 2026 in connection with the achievement of the clinical development milestone and payment for the development milestone was received in April 2026. The Shionogi License Agreement also requires that Shionogi pay the Company tiered royalties ranging from percentages in the low double-digits to twenty on net sales of licensed products, subject to certain deductions. The Company assessed the Shionogi License Agreement in accordance with ASC 606 and concluded that it was a contract with a customer. The Company determined that there is one performance obligation relating to the license to the MZE001 program, including the underlying know-how and certain related materials, and that the transaction price at the inception of the Shionogi License Agreement consisted of the $150.0 million non-refundable upfront cash payment, which was recognized as license revenue in the statements of operations and comprehensive loss during the year ended December 31, 2024 at the point in time when control of the license and related know-how and materials was transferred to Shionogi. The $20.0 million clinical development milestone was recognized as license revenue upon its achievement in March 2026. The remaining potential clinical and regulatory milestones represent variable consideration and were constrained as it was concluded that it was not probable that a significant reversal in cumulative revenue recognized will not occur and therefore are not included in the transaction price as of June 30, 2026. Potential sales milestones and royalties on net product sales will be recognized in the same period that the underlying net product sales occur as they were determined to relate to the license. Neurocrine License Agreement In May 2024, the Company entered into an exclusive license agreement with Neurocrine Biosciences, Inc., or Neurocrine, pursuant to which the Company granted Neurocrine an exclusive worldwide license to a discovery research program targeting ATXN2, or the Neurocrine License Agreement. As consideration for the licensed rights and the transfer of know-how and materials, the Company received an upfront payment of $2.5 million in June 2024. Thereafter, the Company is entitled to potential subsequent payments of up to an aggregate of $24.8 million based on research and development milestones and up to an aggregate of $175.0 million based on sales milestones. The Company is also entitled to tiered royalties ranging in the sub-single-digit to low single-digit percentages on net sales of any licensed product if successfully commercialized. The Company assessed the Neurocrine License Agreement in accordance with ASC 606 and concluded that it was a contract with a customer. The Company determined that there is one performance obligation relating to the license to the ATXN2 discovery program, including the underlying know-how and certain related materials, and that the transaction price consisted of the $2.5 million upfront cash payment. The potential research and development milestones represent variable consideration and were constrained as it was concluded that it was not probable that a significant reversal in cumulative revenue recognized will not occur and therefore not included in the transaction price as of June 30, 2026. Potential sales milestones and royalties on net product sales will be recognized in the same period that the underlying net product sales occur as they were determined to relate to the license. The $2.5 million transaction price was recorded as license revenue in the statements of operations and comprehensive loss during the year ended December 31, 2024, at the point in time when control of the license and the related know-how and materials was transferred to Neurocrine. In August 2026, the Company received notice from Neurocrine of its intent to terminate the Neurocrine License Agreement, effective November 2026, pursuant to the terms of the agreement. The Company does not expect the termination to have a material impact on its previously recognized license revenue.

License Agreements

6 Months Ended

Jun. 30, 2026

License agreements

Trace License Agreement

In March 2024, the Company entered into an exclusive license agreement with Trace Neuroscience, Inc., or Trace, pursuant to which the Company granted an exclusive worldwide license to a discovery research program targeting UNC13A for the treatment of amyotrophic lateral sclerosis, or the Trace License Agreement. As consideration for the licensed rights and the transfer of know-how and materials, the Company received an upfront payment of $15.0 million in April 2024. Thereafter, the Company is entitled to potential subsequent payments of up to an aggregate of $80.0 million based on development and regulatory milestones and up to an aggregate of $250.0 million based on sales milestones. The Company is also entitled to tiered royalties ranging from percentages in the low single-digits to sub-teens on net sales of any licensed product if successfully commercialized.

The Company assessed the Trace License Agreement in accordance with ASC 606 and concluded that it was a contract with a customer. The Company determined that there is one performance obligation relating to the license to the UNC13A discovery program, including the underlying know-how and certain related materials, and that the transaction price consisted of the $15.0 million non-refundable upfront cash payment. The potential future development and regulatory milestones represent variable consideration and were constrained, as it was concluded that it was not probable that a significant reversal in cumulative revenue recognized will not occur and therefore not included in the transaction price as of June 30, 2026. Potential sales milestones and royalties on net product sales will be recognized in the same period that the underlying net product sales occur as they were determined to relate to the license. The $15.0 million transaction price was recorded as license revenue in the statements of operations and comprehensive loss during the year ended December 31, 2024, at the point in time when control of the license and related know-how was transferred to Trace.

Shionogi License Agreement

In March 2024, the Company entered into an exclusive license agreement with Shionogi & Company, Ltd., or Shionogi, pursuant to which the Company granted Shionogi an exclusive, worldwide, sublicensable license to research, develop, manufacture and commercialize MZE001 and certain other small molecule compounds modulating glycogen synthase 1, or the Shionogi License Agreement. As consideration for the licensed rights and the transfer of know-how and materials, the Company received an upfront payment of $150.0 million in May 2024 upon the effectiveness of the Shionogi License Agreement. The Shionogi License Agreement also requires that Shionogi pay the Company up to $275.0 million in the aggregate in milestone payments upon the completion of certain clinical and regulatory milestones and up to $330.0 million in the aggregate in milestone payments if certain sales milestones are achieved. In March 2026, a $20.0 million clinical development milestone was achieved upon dosing of the first patient in Shionogi's Phase 2 study of MZE001 in patients with Pompe disease. The Company recognized $20.0 million as license revenue in the condensed statements of operations and comprehensive loss for the three months ended March 31, 2026 in connection with the achievement of the clinical development milestone and payment for the development milestone was received in April 2026. The Shionogi License Agreement also requires that Shionogi pay the Company tiered royalties ranging from percentages in the low double-digits to twenty on net sales of licensed products, subject to certain deductions.

The Company assessed the Shionogi License Agreement in accordance with ASC 606 and concluded that it was a contract with a customer. The Company determined that there is one performance obligation relating to the license to the MZE001 program, including the underlying know-how and certain related materials, and that the transaction price at the inception of the Shionogi License Agreement consisted of the $150.0 million non-refundable upfront cash payment, which was recognized as license revenue in the statements of operations and comprehensive loss during the year ended December 31, 2024 at the point in time when control of the license and related know-how and materials was transferred to Shionogi. The $20.0 million clinical development milestone was recognized as license revenue upon its achievement in March 2026. The remaining potential clinical and regulatory milestones represent variable consideration and were constrained as it was concluded that it was not probable that a significant reversal in cumulative revenue recognized will not occur and therefore are not included in the transaction price as of June 30, 2026. Potential sales milestones and royalties on net product sales will be recognized in the same period that the underlying net product sales occur as they were determined to relate to the license.

Neurocrine License Agreement

In May 2024, the Company entered into an exclusive license agreement with Neurocrine Biosciences, Inc., or Neurocrine, pursuant to which the Company granted Neurocrine an exclusive worldwide license to a discovery research program targeting ATXN2, or the Neurocrine License Agreement. As consideration for the licensed rights and the transfer of know-how and materials, the Company received an upfront payment of $2.5 million in June 2024. Thereafter, the Company is entitled to potential subsequent payments of up to an aggregate of $24.8 million based on research and development milestones and up to an aggregate of $175.0 million based on sales milestones. The Company is also entitled to tiered royalties ranging in the sub-single-digit to low single-digit percentages on net sales of any licensed product if successfully commercialized.

The Company assessed the Neurocrine License Agreement in accordance with ASC 606 and concluded that it was a contract with a customer. The Company determined that there is one performance obligation relating to the license to the ATXN2 discovery program, including the underlying know-how and certain related materials, and that the transaction price consisted of the $2.5 million upfront cash payment. The potential research and development milestones represent variable consideration and were constrained as it was concluded that it was not probable that a significant reversal in cumulative revenue recognized will not occur and therefore not included in the transaction price as of June 30, 2026. Potential sales milestones and royalties on net product sales will be recognized in the same period that the underlying net product sales occur as they were determined to relate to the license. The $2.5 million transaction price was recorded as license revenue in the statements of operations and comprehensive loss during the year ended December 31, 2024, at the point in time when control of the license and the related know-how and materials was transferred to Neurocrine.

In August 2026, the Company received notice from Neurocrine of its intent to terminate the Neurocrine License Agreement, effective November 2026, pursuant to the terms of the agreement. The Company does not expect the termination to have a material impact on its previously recognized license revenue.