Net Loss Per Share (Tables)

3 Months Ended

Mar. 31, 2014

Net Loss Per Share [Abstract]

Antidilutive securities excluded from the computation of diluted net loss per common share

The following numbers of shares outstanding, prior to the application of the treasury stock method, were excluded from the computation of diluted net loss per common share for the periods presented – because including them would have had an anti-dilutive effect (in thousands):

	Three Months Ended March 31,
	2014		2013
Options to purchase common stock		3,693		3,738
Restricted stock units		170		149
Performance stock units		5		—
Employee stock purchase plan shares		21		32
Total		3,889		3,919