Stock Based Compensation (Tables)

6 Months Ended

Jun. 30, 2019

Share-based Payment Arrangement [Abstract]

Schedule of Total Stock-based Compensation Expense from Stock Options, Restricted Stock and Warrants

The following table sets forth the total stock-based compensation expense resulting from stock options, restricted stock and warrants included in our Condensed Consolidated Statements of Operations:

	Three Months Ended June 30,				Six Months Ended June 30,
	2019		2018		2019			2018
Research and development	$	—	$	29,451	$	(2,672	)	$	60,423
General and administrative — employee		214,706		404,231		427,880			833,220
Total employee stock-based compensation	$	214,706	$	433,682	$	425,208		$	893,643
General and administrative — non-employee		—		19,517		—			40,867
Total non-employee stock-based compensation	$	—	$	19,517	$	—		$	40,867

Schedule of Share-based Payment Award, Fair Value of the Stock Options Granted, Assumptions

The fair value of the stock options was estimated using the Black-Scholes option-pricing model, based on the following assumptions:

	Six Months Ended June 30, 2019		Six Months Ended June 30, 2018
Risk-free interest rate		—		2.42	%
Expected volatility		—		91.6	%
Expected lives (years)		—		6
Expected dividend yield		—		0.00	%

Schedule of Share-based Compensation, Stock Options, Activity

Presented below is our stock option activity:

	Six Months Ended June 30, 2019
	Number of Options (Employees)			Number of Options (Non-Employees)		Total Number of Options			Weighted-Average Exercise Price
Outstanding at January 1, 2019		2,190,835			365,000		2,555,835		$	10.69
Granted		—			—		—		$	—
Exercised, Forfeited or Expired		(178,258	)		—		(178,258	)	$	9.91
Outstanding at June 30, 2019		2,012,577			365,000		2,377,577		$	10.74
Options exercisable at June 30, 2019		1,816,429			365,000		2,181,429		$	11.53

Schedule of Outstanding Stock Options

The following table summarizes significant ranges of outstanding stock options under our plans at June 30, 2019:

Range of Exercise Prices	Total Number of Options		Weighted-Average Remaining Contractual Life (years)		Weighted-Average Exercise Price		Total Number of Options Exercisable		Weighted-Average Remaining Contractual Life (years)		Weighted-Average Exercise Price
$0.77 - $5.00		1,123,458		8.09	$	2.13		927,310		8.07	$	2.16
$5.01 – $11.00		165,834		3.45	$	10.98		165,834		3.45	$	10.98
$11.01 – $15.00		623,193		5.79	$	13.89		623,193		5.79	$	13.89
$15.01 – $48.30		465,092		4.18	$	27.25		465,092		4.18	$	27.25
		2,377,577		6.40	$	10.74		2,181,429		6.24	$	11.53