NET INCOME (LOSS) PER SHARE

12 Months Ended

Dec. 31, 2014

Earnings Per Share [Abstract]

EARNINGS PER SHARE

PER SHARE

Basic net income (loss) per share is calculated by dividing the net income (loss) attributable to common shares by the weighted average number of common shares outstanding during the period. Diluted net income (loss) per share is calculated by dividing the net income (loss) attributable to common shares by the weighted average number of shares outstanding plus dilutive potential common stock outstanding during the period. Potential common shares include the shares of common stock issuable upon the exercise of outstanding stock options, warrants and the purchase of shares from the employee stock purchase plan (using the treasury stock method) as well as the conversion of the excess conversion value on the Notes. As discussed in Note 8, Debt, the Company must settle the principal of the Notes in cash upon conversion, and it may settle any conversion premium in either cash or stock at the Company’s discretion. For purposes of calculating the dilutive impact, it is presumed that the conversion premium will be settled in common stock.

Potential common shares are excluded from the diluted net income (loss) per share computation to the extent that they would be antidilutive. Because the Company reported a net loss for all periods presented, no potentially dilutive securities have been included in the computation of diluted net loss per share.

The following table sets forth the computation of basic and diluted loss per share for the years ended December 31, 2014, 2013 and 2012 (in thousands except per share amounts):

	Year Ended December 31,
	2014			2013			2012
Numerator:
Net loss	$	(13,716	)	$	(63,909	)	$	(52,281	)
Denominator:
Weighted average shares of common stock outstanding	35,299			33,182			30,332
Net loss per share:
Basic and diluted net loss per share of common stock	$	(0.39	)	$	(1.93	)	$	(1.72	)

For the years ended December 31, 2014, 2013 and 2012, the number of potential common shares which were excluded from the diluted net loss per share calculation using the treasury stock method was 5.4 million, 3.4 million and 1.4 million, respectively.

The following outstanding stock options, conversion premium on the Notes, warrants and employee stock purchase plan units which could dilute basic earnings per share in the future are as follows (in thousands):

	Year Ended December 31,
	2014	2013	2012
Weighted average number of stock options outstanding	3,534	3,980	3,304
Conversion premium on the Notes	2,483	1,194	—
Weighted average number of warrants outstanding	21	204	585
Weighted average purchase options under ESPP	1	—	—
Total	6,039	5,378	3,889