Stock-Based Compensation

6 Months Ended

Jun. 30, 2021

Share-based Payment Arrangement [Abstract]

The Company's current equity compensation plan, the 2019 Incentive Plan, was approved by shareholders at the Company's Annual Meeting of Shareholders on May 16, 2019. The 2019 Incentive Plan is administered by the Compensation Committee of the Board of Directors of the Company. Under the terms of the 2019 Incentive Plan, the Company is authorized to grant a variety of incentive awards based on its common stock, including stock options (both incentive stock options and non-qualified stock options), RSUs, performance options/shares and other stock awards to eligible employees and non-employee directors. On May 16, 2019, upon the approval of the 2019 Incentive Plan by shareholders, 3,500,000 shares were authorized for issuance thereunder, plus any shares subject to then-outstanding awards under the 2017 Incentive Plan, the 2015 Incentive Plan and the 2013 Incentive Plan that subsequently were canceled, terminated unearned, expired, were forfeited, lapsed for any reason or were settled in cash without the delivery of shares. On May 12, 2020, at the Company's 2020 Annual Meeting of Shareholders, the Company's shareholders approved an amendment of the 2019 Incentive Plan providing for the issuance of an additional 4,500,000 shares under the plan. On May 12, 2021, at the Company's 2021 Annual Meeting of Shareholders, the Company's shareholders approved the second amendment to the 2019 Incentive Plan providing for the issuance of an additional 2,750,000 shares under the plan. As of June 30, 2021, 4,679,956 shares remained for future issuance under the 2019 Incentive Plan. The 2019 Incentive Plan will terminate on May 16, 2029 unless it is extended or terminated earlier pursuant to its terms. In addition, from time to time, the Company makes inducement grants of stock options to new hires, which awards are made pursuant to the Nasdaq's inducement grant exception to the shareholder approval requirement for grants of equity compensation. During the six months ended June 30, 2021, the Company granted inducement stock options covering 444,070 shares of the Company's common stock to new employees.

On May 15, 2018, the 2018 Employee Stock Purchase Plan (2018 ESPP) was approved by shareholders at the Company's 2018 Annual Meeting of Shareholders. The Company has reserved the following for issuance under the 2018 ESPP: (i) 1,000,000 shares of common stock, plus (ii) commencing on January 1, 2019 and ending on December 31, 2023, an additional number of shares to be added on the first day of each calendar year equal to the lesser of (A) 1,200,000 shares of common stock, (B) 2% of the number of outstanding shares of common stock on such date and (C) an amount determined by the administrator.

Stock Options - As of June 30, 2021, there was $98.9 million of unrecognized compensation expense related to unvested stock options.

From time to time, the Company has granted performance-conditioned options to certain of its employees. Vesting of these options is subject to the Company achieving certain performance criteria established at the date of grant and the grantees fulfilling a service condition (continued employment). As of June 30, 2021, the Company had performance-conditioned options totaling 114,780 shares outstanding which had not yet met the recognition criteria.

Restricted Stock Units — As of June 30, 2021, there was $26.9 million of unrecognized compensation expense related to unvested RSU awards.

The following table summarizes the aggregate stock-based compensation expense recorded in the consolidated statements of comprehensive loss related to stock options and RSUs during the three and six months ended June 30, 2021 and 2020, respectively (in millions):


	Three Months Ended June 30,				Six Months Ended June 30,
	2021		2020		2021		2020
Research and development	$	4.4	$	3.0	$	8.1	$	5.8
Selling, general and administrative	7.4		6.5		14.2		12.7
Total	$	11.8	$	9.5	$	22.3	$	18.5