Significant Accounting Policies, Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Earnings (loss) per share [Abstract]
Net loss	$ (2,129)	$ (3,871)	$ (12,467)	$ (21,911)
Basic [Abstract]
Weighted-average shares of common stock outstanding (in shares)	55,337	54,637	55,116	54,465
Shares used in computing basic loss per share (in shares)	55,337	54,637	55,116	54,465
Basic loss per share (in dollars per share)	$ (0.04)	$ (0.07)	$ (0.23)	$ (0.40)
Diluted [Abstract]
Weighted-average shares of common stock outstanding (in shares)	55,337	54,637	55,116	54,465
Add: Common equivalent shares outstanding (in shares)	0	0	0	0
Shares used in computing diluted loss per share (in shares)	55,337	54,637	55,116	54,465
Diluted loss per share (in dollars per share)	$ (0.04)	$ (0.07)	$ (0.23)	$ (0.40)
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potential common shares outstanding excluded from computation of diluted loss per share (in shares)			6,174	6,011
Stock Options [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potential common shares outstanding excluded from computation of diluted loss per share (in shares)			4,475	3,733
Restricted Stock Units (RSUs) [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potential common shares outstanding excluded from computation of diluted loss per share (in shares)			1,375	1,788
Warrants [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potential common shares outstanding excluded from computation of diluted loss per share (in shares)			324	490