STOCKHOLDERS' EQUITY (Schedule of Stock Option Activity) (Details) $ / shares in Units, $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2020 USD ($) $ / shares shares	Dec. 31, 2019 USD ($) $ / shares shares
Number of Shares
Outstanding, beginning balance (in shares) | shares	6,210,385
Granted (in shares) | shares	146,500
Exercised (in shares) | shares	(285,388)
Canceled (in shares) | shares	(182,616)
Outstanding, ending balance (in shares) | shares	5,888,881	6,210,385
Options vested and exercisable (in shares) | shares	5,199,107
Weighted-Average Exercise Price
Outstanding, beginning balance (in USD per share) | $ / shares	$ 25.10
Granted (in USD per share) | $ / shares	31.42
Exercised (in USD per share) | $ / shares	12.64
Canceled (in USD per share) | $ / shares	47.34
Outstanding, ending balance (in USD per share) | $ / shares	25.17	$ 25.10
Options vested and exercisable (in USD per share) | $ / shares	$ 23.63
Weighted- Average Remaining Contractual Term
Outstanding, Weighted-Average Remaining Contractual Term (in years)	3 years 10 months 24 days	4 years 3 months 18 days
Options vested and exercisable, Weighted-Average Remaining Contractual Term (in years)	3 years 4 months 24 days
Aggregate Intrinsic Value
Outstanding, Aggregate Intrinsic Value | $	$ 21,260	$ 75,805
Options vested and exercisable, Aggregate Intrinsic Value | $	$ 21,260