Share-Based Compensation	6 Months Ended
Jun. 30, 2022
Share-Based Payment Arrangement [Abstract]
Share-Based Compensation	4. SHARE-BASED COMPENSATION The Wave Life Sciences Ltd. 2021 Equity Incentive Plan (the “2021 Plan”) was approved by the Company’s shareholders and went into effect on August 10, 2021. The 2021 Plan serves as the successor to the Wave Life Sciences Ltd. 2014 Equity Incentive Plan, as amended (the “2014 Plan”), such that outstanding awards granted under the 2014 Plan continue to be governed by the terms of the 2014 Plan, but no awards may be made under the 2014 Plan after August 10, 2021. The aggregate number of ordinary shares authorized for issuance of awards under the 2021 Plan is 5,450,000 ordinary shares, plus the number of ordinary shares underlying any awards under the 2014 Plan that are forfeited, cancelled or otherwise terminated (other than by exercise or withheld by the Company to satisfy any tax withholding obligation) on or after August 10, 2021. The 2021 Plan authorizes (and the 2014 Plan previously authorized) the Company’s board of directors or a committee of the board of directors to, among other things, grant non-qualified share options, restricted awards, which include restricted shares and restricted share units (“RSUs”), and performance awards to eligible employees and directors of the Company. Options generally vest over periods of one to four years, and any options that are forfeited or cancelled are available to be granted again. The contractual life of options is generally five or ten years from the grant date. RSUs can be time-based or performance-based. Time-based RSUs generally vest over a period of one to four years. The vesting of performance-based RSUs is contingent on the achievement of certain performance milestones. Any RSUs that are forfeited are available to be granted again. In March 2021, the compensation committee of the Company’s board of directors approved an amendment and restatement of the Company’s outstanding 2019 performance-based RSUs to add an additional milestone to the existing milestones. In 2021, the Company also granted performance-based RSUs with the same terms to certain employees who did not receive the 2019 performance-based RSUs. This modification did not result in any incremental expense. In April 2022, the Company determined that a performance-based RSU milestone was achieved and consequently 50% of the outstanding performance-based RSUs vested, which resulted in the issuance of 384,646 ordinary shares. During the three months ended June 30, 2022, the Company recorded share-based compensation expense of approximately $3.8 million, which represents all of the expense related to the achievement of this performance-based RSU milestone. The Company did not recognize any expense related to the other performance-based RSU milestones, as the remaining milestones were not considered probable of achievement as of June 30, 2022. During the six months ended June 30, 2022, the Company granted 2,037,175 options and 55,075 time-based RSUs to employees. As of June 30, 2022, 1,561,172 ordinary shares remained available for future grant under the 2021 Plan. The Wave Life Sciences Ltd. 2019 Employee Share Purchase Plan (“ESPP”) allows all full-time and certain part-time employees to purchase the Company’s ordinary shares at a discount to fair market value. Eligible employees may enroll in a six-month offering period beginning on or about January 15th and July 15th every year. Shares are purchased at a price equal to 85% of the lower of the fair market value of the Company’s ordinary shares on the first business day or the last business day of an offering period. During the six months ended June 30, 2022, 77,534 ordinary shares were issued under the ESPP. As of June 30, 2022, there were 804,940 ordinary shares available for issuance under the ESPP.

Share-Based Compensation

6 Months Ended

Jun. 30, 2022

Share-Based Payment Arrangement [Abstract]

4. SHARE-BASED COMPENSATION

The Wave Life Sciences Ltd. 2021 Equity Incentive Plan (the “2021 Plan”) was approved by the Company’s shareholders and went into effect on August 10, 2021. The 2021 Plan serves as the successor to the Wave Life Sciences Ltd. 2014 Equity Incentive Plan, as amended (the “2014 Plan”), such that outstanding awards granted under the 2014 Plan continue to be governed by the terms of the 2014 Plan, but no awards may be made under the 2014 Plan after August 10, 2021. The aggregate number of ordinary shares authorized for issuance of awards under the 2021 Plan is 5,450,000 ordinary shares, plus the number of ordinary shares underlying any awards under the 2014 Plan that are forfeited, cancelled or otherwise terminated (other than by exercise or withheld by the Company to satisfy any tax withholding obligation) on or after August 10, 2021.

The 2021 Plan authorizes (and the 2014 Plan previously authorized) the Company’s board of directors or a committee of the board of directors to, among other things, grant non-qualified share options, restricted awards, which include restricted shares and restricted share units (“RSUs”), and performance awards to eligible employees and directors of the Company.

Options generally vest over periods of one to four years, and any options that are forfeited or cancelled are available to be granted again. The contractual life of options is generally five or ten years from the grant date. RSUs can be time-based or performance-based. Time-based RSUs generally vest over a period of one to four years. The vesting of performance-based RSUs is contingent on the achievement of certain performance milestones. Any RSUs that are forfeited are available to be granted again.

In March 2021, the compensation committee of the Company’s board of directors approved an amendment and restatement of the Company’s outstanding 2019 performance-based RSUs to add an additional milestone to the existing milestones. In 2021, the Company also granted performance-based RSUs with the same terms to certain employees who did not receive the 2019 performance-based RSUs. This modification did not result in any incremental expense.

In April 2022, the Company determined that a performance-based RSU milestone was achieved and consequently 50% of the outstanding performance-based RSUs vested, which resulted in the issuance of 384,646 ordinary shares. During the three months ended June 30, 2022, the Company recorded share-based compensation expense of approximately $3.8 million, which represents all of the expense related to the achievement of this performance-based RSU milestone. The Company did not recognize any expense related to the other performance-based RSU milestones, as the remaining milestones were not considered probable of achievement as of June 30, 2022.

During the six months ended June 30, 2022, the Company granted 2,037,175 options and 55,075 time-based RSUs to employees.

As of June 30, 2022, 1,561,172 ordinary shares remained available for future grant under the 2021 Plan.

The Wave Life Sciences Ltd. 2019 Employee Share Purchase Plan (“ESPP”) allows all full-time and certain part-time employees to purchase the Company’s ordinary shares at a discount to fair market value. Eligible employees may enroll in a six-month offering period beginning on or about January 15th and July 15th every year. Shares are purchased at a price equal to 85% of the lower of the fair market value of the Company’s ordinary shares on the first business day or the last business day of an offering period. During the six months ended June 30, 2022, 77,534 ordinary shares were issued under the ESPP. As of June 30, 2022, there were 804,940 ordinary shares available for issuance under the ESPP.