STOCKHOLDERS’ EQUITY / DEFICIT

12 Months Ended

Dec. 31, 2015

Equity [Abstract]

STOCKHOLDERS’ EQUITY / DEFICIT

STOCKHOLDERS’ EQUITY / DEFICIT

Common Stock

The Company is currently authorized to issue up to 100,000,000 shares of $0.0001 par value common stock. All issued shares of common stock are entitled to vote on a 1 share/1 vote basis.

Preferred Stock

The Company is currently authorized to issue up to 20,000,000 shares of $0.001 preferred stock, of which 1,000 shares are designated Class "A" Preferred shares, $0.001 par value. Class A Preferred Shares are not entitled to interest, have certain liquidation preferences, special voting rights and other provisions. No Preferred Shares have been issued to date.

Public Offering - 2015

On March 24, 2015, the Company completed a public offering of 7,866,000 shares of common stock at a price of $19.00 per share. We received net proceeds from the offering of $140.0 million after deducting underwriting fees and other offering costs of $9.5 million. The shares of common stock were offered by us pursuant to a shelf registration statement that was declared effective by the SEC on March 13, 2015.

2014 Incentive Compensation Plan

On May 9, 2014, the Company’s stockholders approved the 2014 Incentive Compensation Plan (the "Plan"). The Plan authorizes the granting of stock options, stock appreciation rights, restricted stock and restricted stock units, deferred stock, performance units and annual incentive awards covering up to 3.0 million shares of the Company’s common stock. In a special shareholder meeting held February 3, 2015, the Company’s shareholders approved an incremental 1,928,000 shares of common stock and 230,000 restricted shared of common stock. These shares were granted to employees between February 24, 2014 and August 18, 2014.

2015 Equity Incentive Plan

On June 8, 2015, the Company's stockholders approved the 2015 Equity Incentive Plan (the "2015 Plan"). The plan is intended as the successor to and continuation of the Plan. Stockholders approved 1.4 million new shares to be issued under the 2015 Plan, in addition to 0.6 million unallocated shares remaining available for issuance under the Plan that were added to the 2015 Plan.

Stock Options

The fair values of stock option grants during the year ended December 31, 2015, 2014 and 2013 were calculated on the date of grant using the Black-Scholes option pricing model, except for options granted for market and revenue performance criteria. Compensation expense is recognized over the period of service, generally the vesting period. During the year ended December 31, 2015, 2,285,000 stock options were granted by the Company. The following weighted average assumptions were used in the Black-Scholes options pricing model to estimate the fair value of stock options for the specified reporting periods:

	Year Ended December 31, 2015		Year Ended December 31, 2014		Year Ended December 31, 2013
Risk free rate	1.53	%	1.55	%	1.51	%
Expected volatility	83	%	85	%	102	%
Expected life (in years)	5.8		5.8		5.8
Expected dividend yield	—		—		—

The risk-free interest rate was based on rates established by the Federal Reserve. The Company’s expected volatility was based on analysis of the Company’s volatility, as well as the volatilities of guideline companies. The expected life of the Company’s options was determined using the simplified method as a result of limited historical data regarding the Company’s activity. The dividend yield is based upon the fact that the Company has not historically paid dividends, and does not expect to pay dividends in the foreseeable future.

The following table summarizes our stock option activity and related information for the year ended December 31, 2015:

			Weighted Average
	Shares Underlying Options		Exercise Price		Remaining Contractual Term (in years)	Aggregate Intrinsic Value (in thousands)
Exercisable at December 31, 2014	1,225,833		$	9.73	7.96	$	3,395
Outstanding at December 31, 2014	4,892,208		$	10.93	8.57	$	8,353
Granted	2,285,000		$	27.15	—	—
Forfeited and expired	(970,170	)	14.91		—	—
Exercised	(541,454	)	13.10		—	—
Outstanding at December 31, 2015	5,665,584		$	17.05	8.75	$	31,542
Exercisable at December 31, 2015	2,036,906		$	12.55	8.34	$	15,582

The weighted average grant date fair value of options granted is $19.02, $8.56, and $6.03 during the years ended December 31, 2015, 2014 and 2013, respectively. The aggregate intrinsic value for outstanding options is calculated as the difference between the exercise price of the underlying awards and the quoted price of the Company’s common stock as of December 31, 2015 of $19.29. Unrecognized compensation cost associated with unvested stock options amounts to $47.4 million as of December 31, 2015, which will be expensed over a weighted average remaining vesting period of 1.9 years.

Restricted Shares

As of December 31, 2015, there was approximately $7.1 million of unrecognized compensation cost related to restricted shares granted.  This amount is expected to be recognized over a weighted average period of 1.8 years.

Unvested restricted shares consist of the following as of December 31, 2015:

	Number of shares		Weighted Average Grant Date Fair Value
Unvested December 31, 2014	691,668		$	10.83
Granted	273,000		26.97
Vested	(478,334	)	11.56
Forfeited/cancelled	(56,668	)	13.97
Unvested December 31, 2015	429,666		$	20.38

Share Based Compensation

Total non-cash stock-based compensation expense consisted of the following for the years ended December 31, 2015 and 2014 (in thousands):

	Year Ended December 31,
	2015		2014		2013
Selling, general and administrative expenses	$	16,483	$	10,940	$	2,651
Research and development expenses	9,417		4,960		259
Total	$	25,900	$	15,900	$	2,910

Exercise of Warrants

During the twelve months ended December 31, 2015, the Company issued 870,306 shares of common stock upon the exercise of warrants for cash received by the Company in the amount of $4.5 million. The Company reclassified $23.5 million derivative liability as equity for the value of these warrants on the date of exercise. The warrants were revalued immediately prior to exercise and the change in the fair value of $2.8 million was recorded as other expense in the consolidated financial statements of the Company.

During the twelve months ended December 31, 2014, the Company issued 1,947,377 shares of common stock upon the exercise of warrants for cash received by the Company in the amount of $8.4 million. The Company reclassified $23.4 million derivative liability as equity for the value of these warrants on the date of exercise. The warrants were revalued immediately prior to exercise and the change in the fair value of the warrants was recorded as other expense in the consolidated financial statements of the Company.

Treasury Stock

In the fourth quarter of 2013, the Company repurchased 130,790 shares of its common stock for an aggregate purchase price of $957,272. The Company currently recognizes such repurchased common stock as treasury stock.

During the year ended December 31, 2014, the Company repurchased 248,801 shares of its common stock for an aggregate purchase price of $2.3 million. The Company recognizes repurchased common stock as treasury stock.

In March 2015 the Company retired 379,591 shares of its common stock held as treasury stock. This was the entire holding of treasury stock. No other shares were repurchased during the year.