Quarterly report pursuant to Section 13 or 15(d)

Stock Based Compensation (Tables)

Stock Based Compensation (Tables)

3 Months Ended

Mar. 31, 2020

Share-based Payment Arrangement, Noncash Expense [Abstract]

Schedule of stock-based compensation expense

The amount of stock-based compensation expense recognized for the three months ended March 31, 2020 and 2019 was as follows:



	Three Months Ended March 31,
	2020		2019
Research and development	$	381,769	$	57,376
General and administrative	679,600		469,125
Sales and marketing	54,954		20,828
Total stock-based compensation, continuing operations	1,116,323		547,329
Total stock-based compensation, discontinued operations	—		49,364
Total stock-based compensation	$	1,116,323	$	596,693

Summary of option activity

The Company has granted awards that contain market-based vesting conditions. The following table summarizes the Company's market-based option activity for the three months ended March 31, 2020:



	Options Outstanding
	Number of shares	Weighted average exercise price per share		Weighted average remaining contractual term (in years)	Aggregate intrinsic value (1)
Balance at December 31, 2019	300,000	$	4.98	9.4
Granted	—
Balance at March 31, 2020	300,000	$	4.98	9.2	$	—
Exercisable at March 31, 2020	—

(1) The aggregate intrinsic value in the above table represents the total pre-tax amount that a participant would receive if the option had been exercised on the last day of the respective fiscal period. Options with a market value less than its exercise value are not included in the intrinsic value amount.

A summary of option activity for the three months ended March 31, 2020 is as follows:



	Options Outstanding
	Number of shares		Weighted average exercise price per share		Weighted average grant date fair value per share		Weighted average remaining contractual term (in years)
Balance at December 31, 2019	4,180,606		$	4.80	$	2.67	7.9
Granted	3,550,583		$	3.97	$	2.51
Exercised	(25,168	)	$	2.95	$	1.90
Forfeited	(125,000	)	$	5.28	$	2.85
Expired	(168,341	)	$	6.16	$	3.35
Balance at March 31, 2020	7,412,680		$	4.37	$	2.58	8.5
Exercisable at March 31, 2020	2,104,285		$	4.43	$	2.50	5.9

Schedule of fair value assumptions for options

The following table shows the assumptions used to compute stock-based compensation expense for stock options granted to employees and members of the board of directors under the Black-Scholes valuation model for the three months ended March 31, 2020:



Service-based options
Expected dividend yield		—%
Expected volatility		69.9% - 71.5%
Expected life (in years)		5.0 - 6.25
Risk-free interest rate		0.37 - 1.48%

Nonvested Restricted Stock Shares Activity

The following table summarizes the Company's RSU activity for the three months ended March 31, 2020:



	RSUs Outstanding
	Number of shares	Weighted average grant date fair value
Unvested RSUs at December 31, 2019	267,500	$	4.92
Granted	—
Unvested RSUs at March 31, 2020	267,500