Share-Based Compensation

12 Months Ended

Dec. 31, 2016

Share-based Compensation

We utilize 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, 2016 and 2015 ($ in thousands):



	Year Ended December 31,
	2016		2015
Cost of revenues	$	333.7	$	545.3
Research and development	339.1		1,811.5
Selling, general and administrative	1,931.6		7,393.3
Total share-based compensation expense	$	2,604.4	$	9,750.1

Total compensation cost related to nonvested awards not yet recognized and the weighted-average periods over which the awards are expected to be recognized at December 31, 2016 were as follows ($ in thousands):



	Stock Options		Restricted Stock
Unrecognized compensation cost	$	1,245.5	$	382.3
Expected weighted-average period in years of compensation cost to be recognized	1.80		1.76

Total fair value of shares vested and the weighted average estimated fair values of shares granted for the years ended December 31, 2016 and 2015 were as follows ($ in thousands):



	Stock Options
	Year Ended December 31,
	2016		2015
Total fair value of shares vested	$	2,359.8	$	6,133.0
Weighted average estimated fair value of shares granted	3.23		19.50

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,
	2016	2015
Expected term - minimum (in years)	5	2
Expected term - maximum (in years)	10	10
Expected volatility - minimum	73%	71%
Expected volatility - maximum	76%	75%
Weighted Average volatility	72%	74%
Expected dividend yield	—	—
Risk-free interest rate - minimum	1.70%	1.19%
Risk-free interest rate - maximum	2.19%	2.14%