9. Stock-Based Compensation

As of June 30, 2020, the Company had 146,224 options to purchase common stock outstanding.

In June 2013, the Company’s shareholders voted to approve the Rexahn Pharmaceuticals, Inc. 2013 Stock Option Plan (the “2013 Plan”).  Under the 2013 Plan, the Company grants equity awards to key employees, directors and consultants of the Company.  The Company has reserved 283,333 shares of common stock for issuance pursuant to the 2013 Plan. As of June 30, 2020, there were 142,066 options outstanding under the 2013 Plan, and 139,236 shares were available for issuance.  In addition, as of June 30, 2020, there were 4,158 options outstanding under a previously established stock option plan under which no new stock options may be granted. 

Accounting for Awards

Stock-based compensation expense is the estimated fair value of options granted amortized on a straight-line basis over the requisite vesting service period for the entire portion of the award. Total stock-based compensation recognized by the Company for the three and six months ended June 30, 2020 and 2019 is as follows:





No income tax benefit has been recognized in the statement of operations for stock-based compensation arrangements as the Company has provided for a 100% valuation allowance on its deferred tax assets.

Summary of Stock Option Transactions



A summary of stock option activity for the six months ended June 30, 2020 is as follows:





A summary of the Company’s unvested options as of June 30, 2020 and changes during the six months ended June 30, 2020 is presented below:



As of June 30, 2020, there was $425,525 of total unrecognized compensation cost related to unvested stock options, which is expected to be recognized over a weighted average vesting period of 2.0 years.