SHAREHOLDERS’ EQUITY AND SHARE-BASED COMPENSATION (Tables)

3 Months Ended

Mar. 31, 2019

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:

	Three months ended  March 31, 2018
	Black-Scholes	Binomial
Risk-free interest rate (%)	2.66 – 2.70	1.65 – 2.77
Expected stock price volatility (%)	70.31 – 71.81	71.81
Expected dividend yield	—	—
Expected option life (in years)	6.00 – 6.25	2.56 – 4.32
Fair value	$16.17 – $17.15	$15.58 – $18.28

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:

	Three months ended March 31,
(in thousands, except per share amounts)	2019		2018
Weighted average grant date fair value of stock options granted per share	$	—	$	16.20
Intrinsic value of options exercised	10		4,320
Grant date fair value of stock options that vested	2,182		23

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 as of December 31, 2018	1,440,566		$	30.78	5.04	$	945
Performance criteria achieved	227,849		24.98
Exercised	(1,500	)	18.79
Forfeited	(25,583	)	61.40
Outstanding as of March 31, 2019	1,641,332		29.51		5.14	1,339
Exercisable as of March 31, 2019	1,007,222		27.10		3.41	1,270

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 and restricted share units
Outstanding as of December 31, 2018	485,806
Granted	358,978
Issued	(31,025	)
Forfeited/canceled	(43,231	)
Outstanding as of March 31, 2019	770,528