Net Loss Per Share (Tables)

12 Months Ended

Dec. 31, 2017

Earnings Per Share [Abstract]

Basic and diluted loss per share

The following table presents the Company's basic and diluted net loss per share (in thousands, except per share amounts):

	For the Years Ended December 31,
	2017			2016			2015
Net loss	$	(61,335	)	$	(66,837	)	$	(85,516	)
Weighted-average shares of common stock outstanding	57,262			55,595			54,171
Net loss per share — basic and diluted	$	(1.07	)	$	(1.20	)	$	(1.58	)

Anti-dilutive shares excluded from calculation of net loss per share

At December 31, 2017, 2016 and 2015, the following potential shares were excluded from the computation of diluted net loss per share because their effect would have been anti-dilutive (in thousands):

	December 31,
	2017	2016	2015
Options to purchase common stock, restricted stock units and performance-based restricted stock units	10,143	10,635	10,860
Shares issuable pursuant to employee stock purchase plan	114	89	77
Convertible notes	11,825	4,682	4,682
Common stock warrants	4,682	4,682	4,682
Total shares excluded from net loss per share	26,764	20,088	20,301