12. Share-Based Compensation

On November 18, 2015, the Company’s Board of Directors adopted and approved the 2015 Equity Incentive Plan (the 2015 Plan), which authorized the Company to grant up to 223,424 ordinary shares in the form of incentive share options, nonstatutory share options, share appreciation rights, restricted share awards, restricted share units and other share awards. The types of share-based awards, including the rights, amount, terms, and exercisability provisions of grants are determined by the Company’s Board of Directors. The purpose of the 2015 Plan is to provide the Company with the flexibility to issue share-based awards as part of an overall compensation package to attract and retain qualified personnel. On May 18, 2017, the Company amended the 2015 Plan to increase the number of ordinary shares available for issuance under the 2015 Plan by 219,605 shares to 443,029 shares.

On March 14, 2018, the Company’s Board of Directors adopted and approved the 2018 Equity Incentive Plan (the 2018 Plan), which became effective upon the execution and delivery of the underwriting agreement related to the Company’s IPO in May 2018. No further grants will be made under the 2015 Plan. The ordinary shares underlying any options that are forfeited, cancelled, repurchased or are otherwise terminated by the Company under the 2015 Plan will not be added back to the ordinary shares available for issuance.

The 2018 Plan authorizes the Company to grant up to 1,018,459 ordinary shares in the form of incentive share options, nonstatutory share options, share appreciation rights, restricted share awards, restricted share units, performance share awards, performance cash awards and other share awards. The types of share-based awards, including the amount, terms, and exercisability provisions of grants are determined by the Company’s Board of Directors. The ordinary shares underlying any options that are forfeited, cancelled, repurchased or are otherwise terminated by the Company under the 2018 Plan will be added back to the ordinary shares available for issuance under the 2018 Plan.

On December 5, 2018, pursuant to powers delegated to it by the Board of Directors of the Company, the Compensation Committee approved an increase in the number of ordinary shares available to be granted pursuant to the 2018 Plan by 4% of the total number of shares of the Company’s issued share capital on December 31, 2018, being 574,081 ordinary shares.

On February 14, 2020, pursuant to powers delegated to it by the Board of Directors of the Company, the Compensation Committee approved, by written resolution, an increase of 594,758 ordinary shares to the number of ordinary shares available to be granted pursuant to the 2018 Plan, being just under 4% of the total number of the Company’s ordinary shares outstanding shares on December 31, 2019, in accordance with the terms of the 2018 Plan.

On June 10, 2020, at the Company’s annual general meeting of shareholders, the shareholders approved and adopted an amended and restated 2018 Plan which, among other things includes an increase of 2,250,000 ordinary shares in the number of ordinary shares reserved for issuance under the 2018 Plan. 

Share Options

No share options were granted to employees and directors during the three months ended March 31, 2021. The Company granted 2,000 share options to employees and directors during the three months ended March 31, 2020, under the 2018 Plan. There were 235,645 and 605,486 unvested employee options outstanding as of March 31, 2021 and March 31, 2020, respectively. Total expense recognized related to employee share options was $164 and $347 for the three months ended March 31, 2021 and 2020, respectively. Total unamortized compensation expense related to employee share options was $806 and $2,621 as of March 31, 2021 and March 31, 2020, respectively, which is expected to be recognized over a remaining average vesting period of 1.21 years and 2.28 years as of March 31, 2021 and March 31, 2020, respectively.

The range of assumptions that the Company used to determine the grant date fair value of employee and director options granted were as follows:

The following table summarizes the number of options outstanding and the weighted-average exercise price as of March 31, 2021:

Restricted Share Units (RSUs)

The Company granted 1,198,136 RSUs to employees and directors during the three months ended March 31, 2021. No RSUs were granted to employees and directors during the three months ended March 31, 2020.

The table below shows the number of RSUs outstanding covering an equal number of the Company’s ordinary shares and the weighted-average grant date fair value of the RSUs outstanding as of March 31, 2021:

The fair value of the RSUs is determined on the date of grant based on the market price of the Company’s ordinary shares on that date. The fair value of RSUs is expensed ratably over the vesting period, which is generally one year for directors and two years for employees. Total expense recognized related to the RSUs was $82 and $24 for the three months ended March 31, 2021 and 2020, respectively. Total unamortized compensation expense related to RSUs was $1,834 and $36 as of three months ended March 31, 2021 and 2020, respectively, which was recognized over a remaining average vesting period of 1.38 and 0.20 years as of March 31, 2021 and March 31, 2020, respectively.

No RSUs, which are subject to certain performance-based vesting conditions (Performance RSUs), were awarded to employees or directors during the three months ended March 31, 2021. The Company awarded 1,079,000 Performance RSUs to certain employees during the three months ended March 31, 2020.

The table below shows the number of Performance RSUs outstanding covering an equal number of the Company’s ordinary shares and the weighted-average grant date fair value of the Performance RSUs outstanding as of March 31, 2021:

The weighted average grant date fair value of Performance RSUs with a market condition was determined using the Monte Carlo simulation model. The fair value of Performance RSUs is expensed evenly over the vesting period. Total expense recognized related to Performance RSUs was $35 and $226 for the three months ended March 31, 2021 and 2020, respectively. All RSUs were fully expensed as of March 31, 2021. Total unamortized compensation expense related to Performance RSUs was $2,150 as of March 31, 2020, which is expected to be recognized over a remaining average vesting period of 0.70 years as of March 31, 2020.

The Company’s share-based compensation expense was classified in the condensed consolidated statements of operations and comprehensive loss as follows:

There was a total of $2,640 and $4,807 unamortized share-based compensation expense for options, RSUs and Performance RSUs as of March 31, 2021 and March 31, 2020, respectively, which is expected to be recognized over a remaining average vesting period of 1.33 years and 1.24 years as of March 31, 2021 and March 31, 2020, respectively.