On May 16, 2013, the Compensation Committee of the Company’s Board of Directors (the “Board”) approved the Gentherm Incorporated 2013 Equity Incentive Plan (the “2013 Plan”), covering 3,500,000 shares of our Common Stock. On May 19, 2017 the 2013 Plan was amended, increasing the amount of available shares by 2,000,000. The 2013 Plan permits the granting of various awards including stock options (including both nonqualified options and incentive options), stock appreciation rights (“SARs”), restricted stock and restricted stock units, performance shares and certain other awards to employees, outside directors and consultants and advisors of the Company. All shares of our Common Stock that remained available for issuance under the Amended and Restated 2006 Stock Incentive Plan (the “2006 Plan”) and the Gentherm Incorporated 2011 Equity Incentive Plan (the “2011 Plan), were reduced to zero; however, some options under the 2006 Plan are still outstanding. As of December 31, 2018, the Company had an aggregate of 1,567,594 shares of Common Stock available to issue under the 2013 Plan.

All plans are administered by the Compensation Committee of the Board. The selection of participants, allotment of shares, determination of price and other conditions are determined by the Compensation Committee at its sole discretion, in order to attract and retain personnel instrumental to the success of the Company. Stock options, for example, granted under such plans have lives for a period of up to ten years from the date of grant at an exercise price which is not less than the fair market value of the Common Stock on the date of the grant.

During the three year period ended December 31, 2018, the Company has outstanding stock options, stock appreciation rights (“SARs”), restricted stock awards and restricted stock units to employees, directors and consultants. These awards become available to the recipient upon the satisfaction of a vesting condition, either based on a period of service or based on the performance of a specific achievement. For equity based awards with a service condition, the requisite service period typically ranges between three to five years for employees and consultants and one year for directors. As of December 31, 2018, there were 129,577 performance based restricted stock units outstanding. These awards vest over a three-year period after the Company’s achievement of either a target return on invested capital ratio (“ROIC”), as defined in the award agreement, for a specified fiscal year, or the Company’s common stock market price returning a target total shareholder return (“TSR”), as defined, during a specific three-year measurement period. Approximately one-half of the performance based restricted stock units are paid based on the ROIC condition, while the other one-half are paid based on the TSR condition. In each case, awards will pay out 50% of the target number of shares for achieving a minimum threshold or up to 200% of the target number of shares for exceeding the target. All other outstanding, unvested equity-based awards were service based. Equity-based award vesting may be accelerated at the discretion of the Board.

Total unrecognized compensation cost related to nonvested options, restricted stock and SARs outstanding under all of the Company’s equity plans was $15,932 and $18,593 as of December 31, 2018 and 2017, respectively. That cost is expected to be recognized over a weighted average period of two years. Compensation expense for the years ended December 31, 2018, 2017 and 2016 was $12,177, $12,727 and $8,147, respectively. No share-based payment arrangements expired during the three-year period ended December 31, 2018. If Gentherm were to realize expired shared-based payment arrangements, they would be reported as a forfeit in the activity roll forward tables below.

The following table summarizes stock option activity during the three-year period ended December 31, 2018:

Options	Shares			Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Term		Aggregate Intrinsic Value
Outstanding at December 31, 2015		1,530,845		$	27.46
Granted		862,000			40.87
Exercised		(112,875	)		13.24
Forfeited		(176,500	)		39.32
Outstanding at December 31, 2016		2,103,470		$	32.72		4.86	$	12,265
Granted		808,500			37.23
Exercised		(202,328	)		13.62
Forfeited		(57,500	)		42.54
Outstanding at December 31, 2017		2,652,142		$	35.34		4.76	$	6,964
Granted		—			—
Exercised		(615,358	)		24.01
Forfeited		(383,784	)		39.59
Outstanding at December 31, 2018		1,653,000			38.53		4.28	$	3,610
Exercisable at December 31, 2016		675,152		$	21.40		3.45	$	9,646
Exercisable at December 31, 2017		984,374		$	29.84		3.44	$	6,534
Exercisable at December 31, 2018		788,125		$	38.15		3.71	$	2,200

The fair value of each option is estimated on the date of grant using the Black-Scholes option-pricing model in order to measure the compensation cost associated with the award. This model incorporates certain assumptions for inputs including a risk-free interest rate, expected dividend yield of the underlying Common Stock, expected option life and expected volatility in the market value of the underlying Common Stock. The following assumptions were used for options issued in the following periods:

Expected volatilities are based on the historical volatility of the Company’s Common Stock. The Company uses historical exercise data and several other factors in developing an assumption for the expected lives of stock options, including the average holding period of outstanding options and their remaining terms. The risk-free interest rate is based upon quoted market yields for United States Treasury debt securities. The expected dividend yield is based upon the Company’s history of having never issued a dividend, the limitations to issue a dividend under terms of the Credit Agreement and management’s current expectation regarding future dividends. We do not expect any of the options granted to be forfeited for purposes of computing fair value.

The weighted-average grant-date fair value of options granted during the year ended December 31, 2017 and 2016 was $9.11 and $10.74, respectively. There were no stock options granted during the year ended December 31, 2018. The total intrinsic value of options exercised during the year ended December 31, 2018, 2017 and 2016 was $5,061, $4,715 and $2,456, respectively.

The following table summarizes restricted stock activity during the three-year period ended December 31, 2018:

Unvested Restricted Shares	Shares			Weighted- Average Grant-Date Fair Value
Outstanding at December 31, 2015		179,026		$	34.92
Granted		141,784			39.73
Vested		(100,330	)		32.47
Forfeited		(9,999	)		40.99
Outstanding at December 31, 2016		210,481		$	39.02
Granted		237,542			37.30
Vested		(165,923	)		37.99
Forfeited		—			—
Outstanding at December 31, 2017		282,100		$	38.06
Granted		21,681			35.00
Vested		(130,684	)		38.62
Forfeited		(36,531	)		37.60
Outstanding at December 31, 2018		136,566		$	37.16

The compensation cost associated with restricted shares is estimated on the date of grant using quoted market prices (Level 1 input). The total fair value of restricted shares vested in 2018, 2017 and 2016 was $4,599, $6,006 and $3,865, respectively.

The following table summarizes restricted stock unit activity during the year ended December 31 2018:

			Performance Based Awards
Unvested Restricted Stock Units	Time Vesting Shares		ROIC Target Shares		TSR Target Shares		Total
Outstanding at December 31, 2017		—		—		—		—
Granted		86,392		64,785		64,792		215,969
Vested		—		—		—		—
Forfeited		—		—		—		—
Outstanding at December 31, 2018		86,392		64,785		64,792		215,969

The following table summarizes SARs activity during the three-year period ended December 31, 2018:

Stock Appreciation Rights	Units			Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Term		Aggregate Intrinsic Value
Outstanding at December 31, 2015		1,049,850		$	34.61
Granted		244,000			40.64
Exercised		(18,750	)		24.28
Forfeited		(30,500	)		28.23
Outstanding at December 31, 2016		1,244,600		$	36.11		4.80	$	3,511
Granted		235,000			38.05
Exercised		(94,250	)		22.21
Forfeited		(193,000	)		32.53
Outstanding at December 31, 2017		1,192,350		$	38.17		4.36	$	2,278
Granted		—			—
Exercised		(204,250	)		26.35
Forfeited		—			—
Outstanding at December 31, 2018		988,100		$	40.61		3.57	$	2,064
Exercisable at December 31, 2016		424,992		$	34.49		4.39	$	2,315
Exercisable at December 31, 2017		613,808		$	37.68		3.72	$	1,904
Exercisable at December 31, 2018		683,600		$	41.21		3.09	$	1,728

The total intrinsic value of SARs converted during the year ended December 31, 2018, 2017 and 2016 was $3,532, $1,495 and $261, respectively.