SHAREHOLDERS’ EQUITY AND SHARE-BASED COMPENSATION (Tables)

6 Months Ended

Jun. 30, 2018

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

Schedule of assumptions used to determine the fair value of options as of the grant date

The following assumptions were used to determine the fair values as of the grant date:

	Six months ended  June 30, 2018		Six months ended  June 30, 2017
	Black-Scholes	Binomial	Black-Scholes	Binomial
Risk-free interest rate (%)	2.66 – 2.98	1.64 – 2.83	2.06 – 2.29	0.77 – 2.38
Expected stock price volatility (%)	70.31 – 71.86	71.81 – 71.86	61.49 – 66.68	66.68
Expected dividend yield	—	—	—	—
Expected option life (in years)	6.00 – 6.25	2.56 – 4.32	6.00 – 7.50	3.53 – 3.85
Fair value	$16.17 – $19.06	$14.67 – $18.28	$23.91 – $24.80	$23.54 – $24.30

Summary of the weighted average fair value of stock options granted, the total intrinsic value of stock options exercised and the fair value of options vested

The following table summarizes the weighted average grant date fair value of stock options granted per share, the total intrinsic value of stock options exercised and the grant date fair value of stock options that vested during the periods presented:

	Six months ended June 30,
(in thousands, except per share amounts)	2018		2017
Weighted average grant date fair value of stock options granted per share	$	16.27	$	24.23
Intrinsic value of options exercised	4,393		875
Grant date fair value of stock options that vested	1,334		1,693

Summary of the activity of the entity's stock options

The following table summarizes the activity related to our stock options:

	Number of options		Weighted average exercise price		Weighted average contractual term (in years)	Aggregate intrinsic value (in thousands)
Outstanding at December 31, 2017	1,745,906		$	28.20	4.96	$	10,202
Granted	271,876		25.06
Exercised	(295,752	)	9.48
Forfeited	(180,578	)	33.91
Outstanding at June 30, 2018	1,541,452		30.56		5.76	5,235
Exercisable at June 30, 2018	921,627		27.03		3.96	5,132

Restricted stock and restricted stock units activity

The following table summarizes the activity related to our restricted shares and restricted share units:

	Number of restricted shares
Outstanding at December 31, 2017	356,509
Granted	305,282
Issued	(88,043	)
Forfeited/canceled	(96,853	)
Outstanding at June 30, 2018	476,895