Stockholders' equity

9 Months Ended

Sep. 30, 2015

Stockholders' Equity Note [Abstract]

Stockholders' equity

Stock Options and Warrants

Warrant activity (including warrants issued to investors and for consulting and advisory services) for the nine months ended September 30, 2015 and 2014 was as follows:

	For the nine months ended September 30,
	2015		2014
Beginning balance outstanding		23,933,922		7,977,990
Warrants issued during the year:
In connection with sales of common and preferred stock		-		17,918,675
In connection with issuance of convertible notes		1,983,340		-
Expired or cancelled during the year		(160,894)		(158,450)
Ending balance outstanding		25,756,368		25,738,215

Option activity for the nine months ended September 30, 2015 and 2014 was as follows:

	For The Nine Months Ended
	September 30,
	2015			2014
Beginning balance outstanding		8,807,667			1,566,667
Issued during the year:		600,000			5,918,000
Expired or cancelled during the year		(740,834	)		(110,000	)
Ending balance outstanding		8,666,833			7,374,667

The numbers and exercise prices of all options and warrants outstanding at September 30, 2015 are as follows:

Shares Outstanding		Weighted Average Exercise Price		Expiration Fiscal Period
	478,312		7.53	4th Qtr, 2015
	300,000		6.50	1st Qtr, 2016
	1,465,833		6.75	2nd Qtr, 2016
	625		9.00	3rd Qtr, 2016
	666,811		7.55	4th Qtr, 2016
	34,749		7.99	1st Qtr, 2017
	1,709,810		7.05	2nd Qtr, 2017
	576,430		1.53	3rd Qtr, 2017
	1,542,338		6.71	4th Qtr, 2017
	10,000		6.60	1st Qtr, 2018
	22,275,623		1.09	1st Qtr, 2019
	893,336		0.92	2nd Qtr, 2019
	1,113,000		1.16	3rd Qtr, 2019
	2,623,000		1.15	4th Qtr, 2019
	525,000		0.92	1st Qtr, 2020
	75,000		0.65	2nd Qtr, 2020
	133,334		7.05	4th Qtr, 2022
	34,423,201

Stock-based Compensation

Results of operations for the three months ended September 30, 2015 and 2014 include stock based compensation costs totaling $199,207 and $1,412,601, respectively, of which $199,207 and $1,296,473, respectively, was charged to personnel related expenses in connection with the issuance of stock options and warrants issued to employees, directors, advisors and consultants (not including shares of stock issued directly for services).  $0 and $116,128 were charged to discontinued operations, respectively.

Results of operations for the nine months ended September 30, 2015 and 2014 include stock based compensation costs totaling $1,053,508 and $4,505,545, respectively, of which $1,053,508 and $3,695,868, respectively, was charged to personnel related expenses in connection with the issuance of stock options and warrants issued to employees, directors, advisors and consultants (not including shares of stock issued directly for services).  $0 and $845,677 were charged to discontinued operations, respectively.

For purposes of accounting for stock based compensation, the fair value of each option and warrant award is estimated on the date of grant using the Black-Scholes-Merton option pricing formula. Compensation expense is recognized upon actual vesting of the options. The following weighted average assumptions were utilized for the calculations during the nine months ended September 30, 2015 and 2014:

	For The Nine Months Ended
	September 30,
	2015			2014
Expected life (in years)	2.89 years			4.23 years
Weighted average volatility		108.92	%		90.14	%
Forfeiture rate		14.21	%		11.43	%
Risk-free interest rate		.97	%		1.14	%
Expected dividend rate		0.00	%		0.00	%

The weighted average expected option and warrant term for employee stock options granted reflects the application of the simplified method set out in SEC Staff Accounting Bulletin No. 107, Share-Based Payment  (SAB 107). The simplified method defines the life as the average of the contractual term of the options and the weighted average vesting period for all options. The Company utilized this approach as its historical share option exercise experience does not provide a reasonable basis upon which to estimate an expected term. Expected volatilities are based on the historical volatility of the Company’s stock. The Company estimated the forfeiture rate based on our expectation for future forfeitures and (for the purpose of computing stock based compensation given the contractual vesting of the Company’s options and warrants outstanding) the Company assumes that all options and warrants will vest. The risk-free rate for periods within the contractual life of the option is based on the U.S. Treasury yield in effect at or near the time of grant. The Company has never declared or paid dividends and has no plans to do so in the foreseeable future.

As of September 30, 2015, $643,576 of total unrecognized compensation cost related to unvested stock based compensation arrangements is expected to be recognized over a weighted-average period of 39.4 months.