Net Loss per Share (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Components of basic and diluted net loss per share
Net loss	$ (145)	$ (3,967)	$ (5,948)	$ (13,064)
Weighted average common shares outstanding	21,691	21,403	21,613	21,374
Net loss per share:
Basic and diluted (in dollars per share)	$ (0.01)	$ (0.19)	$ (0.28)	$ (0.61)
Anti-dilutive securities excluded from the computation of diluted net loss per share
Anti-dilutive securities (in shares)			3,214	2,783
Stock options
Anti-dilutive securities excluded from the computation of diluted net loss per share
Anti-dilutive securities (in shares)			2,717	2,315
Shares of common stock issuable upon the vesting of restricted stock units
Anti-dilutive securities excluded from the computation of diluted net loss per share
Anti-dilutive securities (in shares)			497	468