NET (LOSS) INCOME PER SHARE (Schedule of Basic and Diluted Net Income Per Share) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Earnings Per Share Reconciliation [Line Items]
Net (loss) income	$ (1,020)	$ 10,061	$ (40,513)	$ 23,729
Basic net (loss) income per share:
Weighted-average common shares outstanding (in shares)	73,514	70,773	72,495	75,975
Basic net income per share attributable to common stockholders (in USD per share)	$ (0.01)	$ 0.14	$ (0.56)	$ 0.31
Diluted net (loss) income per share:
Weighted-average common shares outstanding (in shares)	73,514	70,773	72,495	75,975
Number of shares used in diluted calculation (in shares)	73,514	73,712	72,495	79,315
Diluted net income per share attributable to common stockholders (in USD per share)	$ (0.01)	$ 0.14	$ (0.56)	$ 0.30
Stock options
Diluted net (loss) income per share:
Incremental common shares (in shares)	0	2,345	0	2,429
Restricted stock units
Diluted net (loss) income per share:
Incremental common shares (in shares)	0	478	0	870
Employee stock purchase program
Diluted net (loss) income per share:
Incremental common shares (in shares)	0	116	0	41