Stock Compensation

3 Months Ended

Mar. 31, 2020

Share-based Payment Arrangement [Abstract]

12.	Stock Compensation.

For the three-month periods ended March 31, 2020 and 2019, the Company recorded stock-based compensation expense as follo


	Three months ended March 31,
	2020		2019
Research and development	$	418,053	$	287,721
Selling, general and administrative		1,101,298		645,690

Total stock-based compensation	$	1,519,351	$	933,411

Stock Options

As of March 31, 2020, there were outstanding stock options to purchase 12,201,668 shares of common stock, of which stock options to purchase 6,687,980 shares of common stock were exercisable as of March 31, 2020.

During the three-month periods ended March 31, 2020 and 2019, the Company granted seven-year term options to purchase an aggregate of 735,000 and 207,000 shares, respectively, of the Company’s common stock to employees and directors. The Company recorded stock-based compensation related to stock options totaling $1,383,672 and $933,411, respectively, during the three-month periods ended March 31, 2020 and 2019. During the three-month periods ended March 31, 2020 and 2019, respectively, 854,831 and 984,164 options vested.

During the three-month periods ended March 31, 2020 and 2019, options to purchase 11,666 shares and 65,000 shares, respectively, of the Company’s common stock were exercised, with proceeds of $26,149 and $89,350 respectively, to the Company.

As of March 31, 2020, there was approximately $10.4 million of unrecognized compensation expense related to

non-vested

stock option awards granted under the 2014 and 2018 Stock Incentive Plans. The cost is expected to be recognized over a weighted average period of approximately 2.23 years.

Restricted Stock Units

There were no grants of restricted stock units to employees or directors during the three-month periods ended March 31, 2020 and March 31, 2019. During the three-month period ended March 31, 2020, the Company recorded

non-cash

stock-based compensation expense related to restricted stock units totaling $135,679. No stock-based compensation related to restricted stocks was recorded during the three-month period ended March 31, 2019.

As of March 31, 2020, there was approximately $1.5 million of unrecognized compensation expense related to

non-vested

restricted stock units granted under the 2018 Stock Incentive Plan. The cost is expected to be recognized over a weighted average period of approximately 2.67 years.