Stock-Based Compensation

3 Months Ended

Mar. 31, 2014

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

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

11. Stock-Based Compensation

        The Clean Diesel Technologies, Inc. Stock Incentive, as amended (the “Plan”), provides for the awarding of incentive stock options, non-qualified stock options, stock appreciation rights, restricted shares, performance awards, bonuses or other forms of share-based awards, or combinations of these to the Company’s directors, officers, employees, consultants and advisors (except consultants or advisors in capital-raising transactions) as determined by the board of directors. As of March 31, 2014, there were 217,832 shares available for future grants under the Plan.

        Total stock-based compensation expense for the three months ended March 31, 2014 and 2013 was $0.1 million and $0.2 million, respectively.

        Stock Options              

        Stock option activity is summarized as follows:

	Options	Weighted Average Exercise Price		Weighted Average Remaining Contractual Term (in years)		Aggregate Intrinsic Value (thousands)
Outstanding at December 31, 2013	714,712	$	7.17		7.58		─
Cancelled	(79,504)	$	2.83
Outstanding at March 31, 2014	635,208	$	7.71		6.05	$	355
Exercisable at March 31, 2014	556,343	$	8.39		5.78	$	286

        The aggregate intrinsic value represents the difference between the exercise price and the Company’s closing stock price on the last trading day of the year.

        Compensation costs for stock options that vest over time are recognized over the vesting period on a straight-line basis. As of March 31, 2014, the Company had $0.1 million of unrecognized compensation cost related to stock option grants which will be recognized over a weighted estimated period of 0.9 years.

        Restricted Stock Units

        RSU activity is as follows:

	Shares	Weighted Average  Grant Date Fair Value
Outstanding at December 31, 2013	312,196	$	2.37
Granted	288,760	$	3.18
Vested and issued	(58,139)	$	2.06
Forfeited	(101,241)	$	2.14
Outstanding units at March 31, 2014	441,576	$	2.91
Vested and unissued at March 31, 2014	59,589	$	2.49

       During the three months ended March 31, 2014, the Company granted 288,760 RSUs to executive officers and other key employees. The RSUs are time-based and vest over three years from the date of grant.

       As of March 31, 2014, the Company had $1.0 million of unrecognized compensation cost related to RSUs, which will be recognized over a weighted average estimated period of 2.7 years. In 2014, of the 58,139 shares vested, 6,817 vested shares were withheld for minimum statutory tax obligations, resulting in a net issuance of 51,322 shares.