Net Income (Loss) Per Share (Tables)

12 Months Ended

Dec. 31, 2017

Earnings Per Share [Abstract]

Dilutive weighted average securities were excluded from the calculation of diluted net income (loss) per share attributable to common stockholders during the periods

The following potentially dilutive average number of securities were excluded from the calculation of diluted net income per share attributable to common stockholders during the periods presented as the effect was anti-dilutive:

	Year Ended December 31,
	2017	2016	2015
Options to purchase common stock	—	43,513	87,026
Stock appreciation rights	622,633	2,422,716	2,072,130
2019 Convertible notes	5,567,112	7,895,675	10,838,218
2036 Convertible notes	14,106,725	8,209,651	—
Total	20,296,470	18,571,555	12,997,374

Calculation of diluted net income per share

The following table presents the calculation of diluted net income per share for the years ended December 31, 2017, 2016 and 2015 (in thousands, except share and per share data):

	2017			2016			2015
Net income (loss) attributable to the Company's common stockholders - Basic	$	(79,079	)	$	43,453		$	(151,392	)
Plus (less): effect of participating securities	—			874			—
Net income (loss) attributable to common stockholders	(79,079		)	44,327			(151,392		)
Less: effect of participating securities	—			(874		)	—
Net income (loss) attributable to the Company's common stockholders - Diluted	$	(79,079	)	$	43,453		$	(151,392	)
Shares:
Weighted-average shares outstanding - Basic	38,731,015			40,897,549			43,958,803
Adjustment to reflect stock appreciation right conversions	—			5,311			—
Weighted-average shares outstanding - Diluted	38,731,015			40,902,860			43,958,803
Net income (loss) per share attributable to common stockholders - Diluted	$	(2.04	)	$	1.06		$	(3.44	)