NET INCOME (LOSS) PER COMMON SHARE (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Net income (loss)	$ (5,336)	$ 2,384	$ 6,056	$ (9,001)
Shares used in computing basic net income (loss) per common share	79,856	73,413	77,930	72,955
Employee stock options	0	1,170	1,433	0
Employee stock purchase plan	0	0	4	0
Restricted stock and restricted stock units	0	1,732	1,541	0
Shares used in computing diluted net income (loss) per common share (in shares)	79,856	76,315	80,908	72,955
Basic net income (loss) per common share (in usd per share)	$ (0.07)	$ 0.03	$ 0.08	$ (0.12)
Diluted net income (loss) per common share (in usd per share)	$ (0.07)	$ 0.03	$ 0.07	$ (0.12)