Equity (Tables)

12 Months Ended

Dec. 31, 2013

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Stock options activity

Activity with respect to the stock options is summarized as follows:

	Number of Shares		Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Term (in years)	Aggregate Intrinsic Value
Outstanding at January 1, 2013	13,614,135		$	1.42
Granted	4,021,000		$	5.31
Exercised	(1,958,674	)	$	1.01
Unvested options forfeited	(265,002	)	$	3.47
Vested options expired	(35,499	)	$	1.11
Outstanding at December 31, 2013	15,375,960		$	2.46	7.7	$	96,614,260
Vested at December 31, 2013	6,807,732		$	1.33	6.5	$	50,441,475
Vested or expected to vest at December 31, 2013 (a)	15,081,653		$	2.42	7.7	$	95,324,825

(a) Includes forfeiture adjusted unvested shares.

Summary of stock options outstanding and exercisable

Following is a summary of stock options outstanding and exercisable at December 31,

		2013
	Options Outstanding				Options Exercisable
Range of Exercise Prices	Number outstanding	Weighted- Average Remaining Contractual Term (in years)	Weighted- Average Exercise Price		Number Exercisable	Weighted- Average Exercise Price
$0.50 - $0.76	1,225,935	4.0	$	0.65	1,225,935	$	0.65
$0.87 - $1.35	6,570,341	7.6	1.20		3,604,469	1.18
$1.40 - $2.29	1,571,700	6.1	1.66		1,321,698	1.66
$2.33 - $3.75	2,091,984	8.7	2.77		655,630	2.77
$3.95 - $6.02	3,435,500	9.3	5.13		—	—
$6.04 - $7.93	480,500	8.9	6.61		—	—
	15,375,960	7.7	$	2.46	6,807,732	$	1.33

Unvested Stock Options Roll Forward

A summary of the status of the Company’s unvested stock options as of December 31 is presented below:

	2013
Unvested Stock Options	Number of Shares		Weighted- Average Grant Date Fair Value
Unvested at January 1, 2013	8,377,538		$	0.96
Granted	4,021,000		$	3.08
Cancelled/expired	(265,002	)	$	2.14
Vested	(3,565,308	)	$	0.94
Unvested at December 31, 2013	8,568,228		$	1.94

Fair value of options valuation assumptions

The assumptions used in calculating the fair value of options using the Black-Scholes-Merton option-pricing model are set forth in the following table:

	Year ended December 31,
	2013	2012	2011
Expected volatility	61.41 - 64.77%	45.7 - 64.3%	57.3-58.1%
Expected life (in years)	6	6	6
Expected dividend yield	—	—	—
Risk-free interest rate	0.85 - 1.88%	0.62 - 1.77%	0.86 - 2.24%

Restricted Stock Awards Roll Forward

Following is summary information for restricted stock awards for the years ended 2013 and 2012. There were no restricted stock awards in 2011 and prior years. Shares vest over a one to three year period. As of December 31, 2013, there was approximately $2,471,000 of total unrecognized stock-based compensation related to time-based, nonvested restricted stock.  That expense is expected to be recognized on a straight-line basis over a weighted-average period of 2.5 years.

	Number of Shares		Weighted-Average Grant Date Fair Value
Unvested at December 31, 2011	—		—
Granted	7,500		$3.49
Vested	—		—
Unvested at December 31, 2012	7,500		$3.49
Granted	576,550		$5.55
Vested	(2,500	)	$3.49
Forfeited	(5,000	)	$6.60
Unvested at December 31, 2013	576,550		$5.53

Allocation of Share-based Compensation

For the years ended December 31, 2013, 2012, and 2011 the Company recognized stock-based compensation as follows:  

	Year Ended December 31,
	2013		2012		2011
Cost of sales	$	279,215	$	97,970	$	98,366
Research and development	417,436		289,341		254,997
Selling, general and administrative	5,312,525		2,151,410		1,305,720
	$	6,009,176	$	2,538,721	$	1,659,083

Summary of warrants outstanding

Common Stock warrants activity and resulting balances for the years ended December 31, 2013, 2012, and 2011 are as follows:

	Number of Warrants		Weighted- Average Exercise Price per Warrant		Number of Contingent Warrants		Weighted- Average Exercise Price per Contingent Warrant
Warrants outstanding at January 1, 2011	6,003,924		$	1.21	1,252,990		$	0.01
Issued in connection with private placement of common stock	1,889,161		1.50		1,889,162		0.01
Issued in connection with convertible promissory notes	203,332		1.50		203,332		0.01
Issued in connection with line of credit with related party	—		—		650,000		0.01
Issued in connection with Senior Secured Promissory Notes	1,250,000		0.01		1,250,000		0.01
Placement agent	42,400		1.09		—		—
Warrants outstanding at December 31, 2011	9,388,817		$	1.00	5,245,484		$	0.01
Warrants outstanding at January 1, 2012	9,388,817		$	1.00	5,245,484		$	0.01
Warrants issued:
Vested contingent warrants related to private placement of common stock	1,672,743		0.01		(1,672,743	)	0.01
Vested contingent warrants related to line of credit with related party	325,000		0.01		(325,000	)	0.01
Contingent warrants voided	—		—		(3,247,741	)	0.01
Warrants exercised:
Contingent warrants related to convertible note	(1,249,750	)	0.01		—		—
Contingent warrants related to private placement of common stock	(1,608,802	)	0.01		—		—
Contingent warrants related to line of credit with related party	(325,000	)	0.01		—		—
Callable warrants	(3,288,733	)	1.50		—		—
Other	(1,703,568	)	0.63		—		—
Warrants expired	(10,000	)	1.00		—		—
Warrants redeemed for cashless exercises	(14,789	)	0.53		—		—
Repurchased callable warrants	(56,750	)	1.50		—		—
Warrants outstanding at December 31, 2012	3,129,168		$	1.04	—		$	—
Warrants outstanding at January 1, 2013	3,129,168		1.04		—		—
Warrants exercised:
Other	(1,844,352	)	1.14		—		—
Warrants outstanding at December 31, 2013	1,284,816		$	0.90	—		$	—