Stock Options and Warrants (Tables)

The following table summarizes significant ranges of outstanding stock options under the two plans at December 31, 2014:

Range of Exercise Prices		Number of Options		Weighted Average Remaining Contractual Life (years)		Weighted Average Exercise Price		Number of Options Exercisable		Weighted Average Contractual Life		Weighted Average Exercise Price
$	1.83 — 2.50		7,932,558		8.99	$	2.19		3,801,902		8.99	$	2.17
$	2.51 — 3.50		774,482		8.89		2.78		691,387		8.89		2.75
$	3.51 — 8.00		989,201		6.04		6.27		755,871		6.04		6.57
$	8.01 — 32.55		344,494		2.38		8.93		344,494		2.38		8.93

			10,040,735		8.46	$	2.87		5,593,654		8.46	$	3.25

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

	2014			2013			2012
Risk-free interest rate		1.74% - 2.12	%		0.91% - 2.79	%		0.83% - 1.78	%
Expected volatility		82% - 90	%		85% - 89	%		0% - 82	%
Expected lives (years)		6 - 10			6 - 10			6 - 10
Expected dividend yield		0.00	%		0.00	%		0.00	%

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

	2014			2013			2012
Risk-free interest rate		2.23	%		2.05	%		—
Expected volatility		85.0	%		84.8	%		—
Expected lives (years)		10			10			—
Expected dividend yield		0	%		0	%		—

Presented below is the Company’s non-employee stock option activity:

	Stock Options								Weighted Average Exercise Price
	2014			2013		2012			2014		2013		2012
Outstanding — beginning of year		167,143			142,143		143,572		$	5.69	$	6.20	$	6.17
Granted		550,000			25,000		—			2.76		2.79		—
Exercised		—			—		(1,429	)		—		—		2.94
Forfeited		(25,000	)		—		—			2.79		—		—
Outstanding — end of year		692,143			167,143		142,143			3.47		5.69		6.20
Exercisable at end of year		692,143			167,143		133,215		$	3.47	$	5.69	$	6.10
Weighted average fair value of stock options granted during the year:	$	2.32		$	1.98	$	—

Presented below is the Company’s stock option activity for employees and directors:

	Stock Options									Weighted Average Exercise Price
	2014			2013			2012			2014		2013		2012
Outstanding — beginning of year		6,228,593			3,240,850			1,763,923		$	3.11	$	4.08	$	6.01
Granted		3,180,000			3,323,176			1,541,002			2.47		2.43		1.86
Exercised		(1,667	)		(476	)		(1,071	)		1.83		1.93		2.80
Forfeited		(24,333	)		(127,812	)		(63,004	)		2.81		3.09		3.89
Expired		(34,001	)		(207,145	)		—			8.18		9.59		—
Outstanding — end of year		9,348,592			6,228,593			3,240,850			2.83		3.11		4.08
Exercisable at end of year		4,901,511			3,125,720			1,918,461		$	3.22	$	3.86	$	3.69
Weighted average fair value of stock options granted during the year:	$	1.80		$	1.82		$	1.44

A summary of the Company’s warrant activity and related information for the years ended December 31 are shown below.

	Warrants									Weighted Average Exercise Price
	2014			2013			2012			2014		2013		2012
Outstanding — beginning of year		8,324,609			7,518,113			7,397,415		$	4.86	$	5.09	$	5.32
Granted		25,000			816,667			285,716			5.60		2.80		2.06
Exercised		(340,527	)		(8,572	)		(5,714	)		2.56		4.48		1.89
Forfeited		—			—			(28,571	)		—		—		1.89
Expired		(659,322	)		(1,599	)		(130,733	)		12.66		14.99		11.90
Outstanding — end of year		7,349,760			8,324,609			7,518,113			4.27		4.86		5.09
Exercisable at end of year		7,149,760			7,924,609			7,452,396		$	4.32	$	4.98	$	5.11
Weighted average fair value of warrants granted during the year	$	3.46		$	1.31		$	1.22

The following table summarizes additional information concerning warrants outstanding and exercisable at December 31, 2014:

		Warrants Outstanding
Range of Exercise Prices		Number of Shares		Weighted Average Remaining Contractual Life (years)		Weighted Average Exercise Price		Warrants Number of Shares Exercisable		Exercisable Weighted Average Exercise Price
$	2.10 — 2.60		645,716		3.05	$	2.42		445,716	$	2.38
$	2.61 — 3.60		125,000		0.86		3.00		125,000		3.00
$	3.61 — 4.60		6,496,899		1.57		4.47		6,496,899		4.47
$	4.61 — 5.60		82,145		3.20		5.41		82,145		5.41
			7,349,760		1.71	$	4.27		7,149,760	$	4.32