On April 17, 2017, the Company’s Board of Directors adopted the 2017 Incentive Award Plan (the “2017 Plan”), which became effective upon approval by the Company’s stockholders on May 23, 2017. The 2017 Plan replaced and superseded in its entirety the 2007 Incentive Award Plan (the “2007 Plan”), which expired pursuant to its terms on May 24, 2017. A total of 15,000,000 shares of Class A common stock are reserved for issuance under the 2017 Plan, which provides for grants of ISOs, non-qualified stock options, restricted stock, employee stock purchase plan, and various other types of equity awards as described in the plan to the employees, consultants and directors of the Company and its subsidiaries. The 2017 Plan is administered by the Company’s Board of Directors with respect to awards to non-employee directors and by the Company’s Compensation Committee with respect to other eligible participants.

For stock-based awards, the Company recognizes compensation expense based on the grant date fair value. Share‑based compensation expense was $29.7 million and $10.7 million for the three months ended September 30, 2020 and 2019. Share-based compensation expense was $55.0 million and $30.2 million for the nine months ended September 30, 2020 and 2019. Included in the compensation expense recognized in 2020 is an $18.2 million non-cash charge related to the cancellation of 750,000 unvested shares as a result of a legal settlement. During the three and nine months ended September 30, 2020, the Company redeemed 171,120 shares of Class A common stock for $5.7 million to satisfy employee tax withholding requirements. During the three and nine months ended September 30, 2019, the Company repurchased 4,821 and 423,206 shares of Class A common stock for $0.2 million and $13.7 million to satisfy employee tax withholding requirements, respectively.

A summary of the status and changes of the Company’s unvested shares related to the 2007 Plan and the 2017 Plan as of and for the nine months ended September 30, 2020 is presented below:

As of September 30, 2020, there was $66.0 million of unrecognized compensation cost related to unvested common shares. The cost is expected to be amortized over a weighted average period of 1.8 years.