Share-Based Compensation

Share-based Compensation

The Company utilizes share-based compensation in the form of stock options and restricted stock. The following table summarizes the components of share-based compensation expense for the years ended December 31, 2019 and 2018 ($ in thousands):



	Year Ended December 31,
	2019		2018
Research and development	$	274	$	446
General and administrative	1,021		2,007
Total share-based compensation expense	$	1,295	$	2,453

Total compensation cost related to unvested awards not yet recognized and the weighted-average periods over which the awards are expected to be recognized at December 31, 2019 were as follows ($ in thousands):



	Stock Options		Restricted Stock Units		Restricted Stock
Unrecognized compensation cost	$	646	$	49	$	403
Expected weighted-average period in years of compensation cost to be recognized	1.57		1.43		1.82

Total fair value of shares vested and the weighted average estimated fair values of shares granted for the years ended December 31, 2019 and 2018 were as follows ($ in thousands):



	Stock Options
	Year Ended December 31,
	2019		2018
Total fair value of shares vested	$	399	$	218
Weighted average estimated fair value of shares granted	3.18		2.61

Valuation Assumptions

The fair value of stock options at the date of grant was estimated using the Black-Scholes option pricing model. The expected volatility is based upon historical volatility of the Company’s stock. The expected term for the options is based upon observation of actual time elapsed between date of grant and exercise of options for all employees.

The range of assumptions made in calculating the fair values of stock options was as follow:



	Stock Options
	Year Ended December 31,
	2019	2018
Expected term - minimum (in years)	6	5.5
Expected term - maximum (in years)	6	6
Expected volatility - minimum	74%	68%
Expected volatility - maximum	74%	73%
Weighted Average volatility	74%	72%
Expected dividend yield	—	—
Risk-free interest rate - minimum	2.35%	2.35%
Risk-free interest rate - maximum	2.62%	2.96%