Stock Based Compensation	3 Months Ended
Mar. 31, 2021
Stock Based Compensation
Stock Based Compensation	Note 2. Stock-Based Compensation We maintain the Axcelis Technologies, Inc. 2012 Equity Incentive Plan, as amended (the “2012 Equity Plan”), which became effective on May 2, 2012, and permits the issuance of options, restricted stock, restricted stock units (“RSUs”) and performance awards to selected employees, directors and consultants of the Company. Our 2000 Stock Plan (the “2000 Stock Plan”) expired on May 1, 2012 and no new grants may be made under that plan after that date. However, unexpired options granted under the 2000 Stock Plan, which have a 10-year term, remain outstanding and subject to the terms of the 2000 Stock Plan. We also maintain the Axcelis Technologies, Inc. 2020 Employee Stock Purchase Plan (the “2020 ESPP”), an Internal Revenue Code Section 423 plan. The 2012 Equity Plan is more fully described in Note 13 to the consolidated financial statements in our Annual Report on Form 10-K for the year ended December 31, 2020. We recognized stock-based compensation expense of $2.4 million and $1.7 million for the three-month periods ended March 31, 2021 and 2020, respectively. These amounts include compensation expense related to RSUs and non-qualified stock options. In the three-month periods ended March 31, 2021 and 2020, we issued 0.3 million and 0.6 million shares of common stock, respectively, upon stock option exercises and vesting of RSUs. In the three-month periods ended March 31, 2021 and 2020, we received proceeds of $2.5 million and $4.5 million, respectively, in connection with the exercise of stock options.

Stock Based Compensation

3 Months Ended

Mar. 31, 2021

Note 2. Stock-Based Compensation

We maintain the Axcelis Technologies, Inc. 2012 Equity Incentive Plan, as amended (the “2012 Equity Plan”), which became effective on May 2, 2012, and permits the issuance of options, restricted stock, restricted stock units (“RSUs”) and performance awards to selected employees, directors and consultants of the Company. Our 2000 Stock Plan (the “2000 Stock Plan”) expired on May 1, 2012 and no new grants may be made under that plan after that date. However, unexpired options granted under the 2000 Stock Plan, which have a 10-year term, remain outstanding and subject to the terms of the 2000 Stock Plan. We also maintain the Axcelis Technologies, Inc. 2020 Employee Stock Purchase Plan (the “2020 ESPP”), an Internal Revenue Code Section 423 plan.

The 2012 Equity Plan is more fully described in Note 13 to the consolidated financial statements in our Annual Report on Form 10-K for the year ended December 31, 2020.

We recognized stock-based compensation expense of $2.4 million and $1.7 million for the three-month periods ended March 31, 2021 and 2020, respectively. These amounts include compensation expense related to RSUs and non-qualified stock options.

In the three-month periods ended March 31, 2021 and 2020, we issued 0.3 million and 0.6 million shares of common stock, respectively, upon stock option exercises and vesting of RSUs. In the three-month periods ended March 31, 2021 and 2020, we received proceeds of $2.5 million and $4.5 million, respectively, in connection with the exercise of stock options.