COMMON STOCK AND STOCK-BASED COMPENSATION PLANS (Tables)

6 Months Ended

Jun. 30, 2017

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

A summary of the Company’s stock option and SARs activities and related information for the six months ended June 30, 2017, are as follows:


	Number of options and SAR units (1)			Weighted average exercise price		Weighted average remaining contractual term		Aggregate intrinsic-value
Outstanding as of December 31, 2016		1,455,908		$	19.76
Granted		—			—
Exercised		(572,520	)		19.72
Forfeited or expired		(12,514	)		17.58

Outstanding as of June 30, 2017 (2)		870,874		$	19.82		5.4	$	22,324

Exercisable as of June 30, 2017 (3)		565,168		$	19.08		4.7	$	14,902

(1)	The SAR units are convertible for a maximum number of shares of the Company’s common stock equal to 75% of the SAR units subject to the grant.

(2)	Due to the ceiling imposed on the SAR grants, the outstanding amount equals a maximum of 790,118 shares of the Company’s common stock issuable upon exercise.

(3)	Due to the ceiling imposed on the SAR grants, the exercisable amount equals a maximum of 515,026 shares of the Company’s common stock issuable upon exercise.

Summary of Restricted Stock Units Activity

A summary of the Company’s RSU activities and related information for the six months ended June 30, 2017, are as follows:


	Number of RSUs			Weighted Average Grant-Date Fair Value
Unvested as of December 31, 2016		505,142		$	21.59
Granted		224,600			35.21
Vested		(166,208	)		20.45
Forfeited or expired		(18,438	)		23.58

Unvested as of June 30, 2017		545,096		$	27.48

Equity-Based Compensation Expense Included in Interim Condensed Consolidated Statements of Income

The following table shows the total equity-based compensation expense included in the interim condensed consolidated statements of income:


	Six months ended June 30,				Three months ended June 30,
	2017		2016		2017		2016
	(unaudited)		(unaudited)		(unaudited)		(unaudited)
Cost of revenue	$	205	$	114	$	114	$	54
Research and development, net		1,843		1,421		972		775
Sales and marketing		659		502		370		255
General and administrative		1,420		1,046		722		525

Total equity-based compensation expense	$	4,127	$	3,083	$	2,178	$	1,609

Assumptions Used to Estimate Fair Value of Employee Stock Purchase Plan

The fair value for rights to purchase shares of common stock under the Company’s employee stock purchase plan was estimated on the date of grant using the following assumptions:


	Six months ended
	June 30,
	2017			2016
	(unaudited)			(unaudited)
Expected dividend yield		0	%		0	%
Expected volatility		35%-46	%		36%-57	%
Risk-free interest rate		0.5%-0.7	%		0.3%-0.5	%
Expected forfeiture		0	%		0	%
Contractual term of up to		24 months			24 months