21. Loss per Share

The following table illustrates the computation of basic and diluted loss per common share:


	Year Ended December 31,
	2015			2014			2013
Net loss	$	(84,867	)	$	(117,232	)	$	(64,203	)
Weighted average common stock outstanding
Basic		34,380,517			34,055,513			35,232,194
Diluted		34,380,517			34,055,513			35,232,194
Loss per share
Basic	$	(2.47	)	$	(3.44	)	$	(1.82	)
Diluted	$	(2.47	)	$	(3.44	)	$	(1.82	)

The following outstanding instruments were excluded from the computation of diluted loss per share, as they would have an anti-dilutive effect on the calculation:


	Year Ended December 31,
	2015		2014		2013
Options		3,179,899		3,215,945		2,944,645
Warrants		—		—		1,426,330
Restricted Stock Units		135,370		—		—

Rights Plan

On March 5, 2015, the Board of Directors of the Company, authorized and declared a dividend of one preferred stock purchase right (a “Right” and collectively, the “Rights”) for each share of the Company’s common stock, par value $0.01 per share, outstanding at the close of business on March 16, 2015. Each Right, once exercisable, will entitle the registered holder to purchase from the Company one one-thousandth of a share of Series A Junior Participating Preferred Stock, par value $0.01 per share, at a purchase price of $24, subject to adjustment (the “Purchase Price”). The Rights are not presently exercisable and remain attached to the shares of common stock unless and until the occurrence of the earlier of the following (the “Distribution Date”): (i) the tenth day after the public announcement or disclosure by the Company or any person or group of affiliated or associated persons that any person or group of affiliated or associated persons has become an “Acquiring Person” by obtaining beneficial ownership of 10% (or 20% in the case of a “passive institutional investor,” which is defined generally as any person who has reported beneficial ownership of shares of common stock on Schedule 13G under the Securities Exchange Act of 1934 (“the Exchange Act”)) or more of the Company’s outstanding common stock, subject to certain exceptions; or (ii) the tenth business day (or such later date as the Company’s Board of Directors may designate before a person or group of affiliated or associated persons becomes an Acquiring Person) after the commencement of, or first public announcement of the intent of any person to commence, a tender or exchange offer by any person or group of affiliated or associated persons, which would, if consummated, result in such person or group becoming an Acquiring Person. The Board of Directors may redeem all of the Rights for $0.001 per Right at any time before any person or group of affiliated or associated persons becomes an Acquiring Person. In addition, at any time on or after any person or group of affiliated or associated persons becomes an Acquiring Person (but before any person or group of affiliated or associated persons becomes the owner of 50% or more of the Company’s outstanding common stock), the Board of Directors may exchange all or part of the Rights (other than the Rights beneficially owned by the Acquiring Person and certain affiliated persons) for shares of common stock at an exchange ratio of one share of common stock per Right. The Rights will expire at the close of business on March 5, 2016, unless redeemed or exchanged prior to that time.

If any person or group of affiliated or associated persons becomes an Acquiring Person, then, after the Distribution Date, each Right (other than Rights beneficially owned by the Acquiring Person and certain affiliated persons or transferees thereof) will entitle the holder to purchase, for the Purchase Price, a number of shares of common stock having a market value of twice the Purchase Price. Alternatively, if, after any person or group of affiliated or associated persons becomes an Acquiring Person, (i) the Company is involved in a merger or other business combination in which the Company is not the surviving corporation or its common stock is changed into or exchanged for other securities or assets; or (ii) the Company or one or more of its subsidiaries sells or otherwise transfers assets or earning power aggregating more than 50% of the assets or earning power of the Company and its subsidiaries, taken as a whole, then each Right will entitle the holder to purchase, for the Purchase Price, a number of shares of common stock of the other party to such business combination or sale (or in certain circumstances, an affiliate) having a market value of twice the Purchase Price.