Shareholders' Equity (Tables)

12 Months Ended

Dec. 31, 2020

Shareholders' Equity [Abstract]

Fair Value Assumptions

The fair value of each option award is estimated on the date of grant using the Black-Scholes-Merton option-pricing model that used the weighted average assumptions in the following table and recognized over the vesting period of four years. The risk‑free rate for the expected term of the option is based on the U.S. Treasury yield curve in effect at the time of grant.

	2017 Grant
Valuation assumptions:
Dividend yield *	0
Expected volatility	66%
Risk-free interest rate	1.87%
Expected life (years) **	4.8

*The option grant was made prior to the dividend distribution. As such, the valuation assumptions reflect the Company’s previous record of not paying dividends.

**Expected life for the periods presented was determined according to the simplified method since, at the date of grant, the Company did not have enough history to make an estimate.

Stock Option Activity

Share option activity during the past three years is as follows:

	Year Ended December 31,
	2020					2019					2018
	Number of options			Weighted average exercise price US$		Number of options			Weighted average exercise price US$		Number of options			Weighted average exercise price US$
Outstanding at January 1		309,792			3.29		519,785			3.16		1,173,433			2.80
Forfeited and cancelled		(12,876	)		3.74		(10,750	)		2.41		(43,159	)		2.53
Exercised		(206,991	)		3.04		(199,243	)		2.69		(610,489	)		2.79
Outstanding at year end		89,925			3.80		309,792			3.29		519,785			3.16
Exercisable at year end		63,253			3.55		225,110			3.08		217,976			2.85

Schedule of Options Outstanding

B.Stock Option Plan (cont’d)

	Number of options outstanding		Weighted average exercise price US$		Weighted Average Remaining Contractual term (years)		Aggregate intrinsic Value (in US$ thousands)
Outstanding as of December 31, 2020		89,925		3.80		2.28		1,628
Exercisable at December 31, 2020		63,253		3.55		1.66		1,161

Information about Share Options

The following table summarizes information about share options at December 31, 2020:

Exercise price US$	Number of outstanding options		Number exercisable		Weighted average remaining Contractual term (years) of outstanding options
0-2		5,000		5,000		2.22
2-5		84,925		58,253		2.28
		89,925		63,253		2.28

Information about Nonvested Options

The following table summarizes information about non-vested options at December 31, 2020:

	Options			Weighted average grant-date fair value
Balance at January 1, 2020		84,682			2.40
Granted		-			-
Vested		(55,385	)		2.15
Forfeited		(2,625	)		2.42
Balance at December 31, 2020		26,672			2.93

Restricted Share Unit Activity

	RSUs			Weighted average grant date value
Balance at January 1, 2020		1,233,402		$	8.83
Granted		506,500		$	11.83
Vested		(391,008	)	$	8.16
Forfeited		(11,210	)	$	7.94
Balance at December 31, 2020		1,337,684		$	9.52