STOCKHOLDERS' EQUITY (Tables)

3 Months Ended

Mar. 31, 2018

Stockholders' Equity Note [Abstract]

Schedule of Stock by Class

The following table presents the number of shares authorized and issued as of the dates indicated:

	March 31, 2018		December 31, 2017
	Shares Authorized	Shares Issued	Shares Authorized	Shares Issued
Stockholders’ equity:
Common stock, $0.000001 par value	200,000,000	83,956,890	200,000,000	83,724,916
Undesignated Preferred Stock	10,000,000	—	10,000,000	—

Schedule of Stock Option Activity

A summary of stock option activity for the three months ended March 31, 2018 is as follows:

	Options Outstanding
	Number of Shares		Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Term (in years)	Aggregate Intrinsic Value (in thousands)
Outstanding - December 31, 2017	7,078,932		$	22.70	5.56	$	145,613
Granted	671,250		43.58
Exercised	(313,437	)	18.13
Canceled	(44,397	)	49.20
Outstanding - March 31, 2018	7,392,348		$	24.63	5.81	$	136,698
Options vested and exercisable as of March 31, 2018	5,642,395		$	20.94	4.84	$	125,460

Schedule of RSU Activity

A summary of RSU activity for the three months ended March 31, 2018 is as follows:

	Restricted Stock Units
	Number of Shares		Weighted- Average Grant Date Fair Value
Unvested - December 31, 2017	7,249,205		$	34.57
Granted	1,278,021		43.88
Released	(783,737	)	35.81
Canceled	(289,851	)	34.88
Unvested - March 31, 2018	7,453,638		$	36.02

Schedule of Stock-Based Compensation Expense

The following table summarizes the effects of stock-based compensation expense related to stock-based awards in the condensed consolidated statements of operations during the periods presented (in thousands):

	Three Months Ended March 31,
	2018		2017
Cost of revenue	$	1,030	$	981
Sales and marketing	7,518		6,868
Product development	13,435		11,208
General and administrative	5,751		5,277
Total stock-based compensation	$	27,734	$	24,334