Incentive Award Plan and Employee Stock Purchase Plan

9 Months Ended

Sep. 30, 2013

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

Incentive Award Plan and Employee Stock Purchase Plan

Incentive Award Plan and Employee Stock Purchase Plan. OnMarch 4, 2013, the Chief Executive Officer (the "CEO") was awarded143,182restricted stock units ("RSUs") with a grant date fair market value of$3.2 million, which will vest inthreeequal annual increments on January 4, 2014, January 4, 2015 and January 4, 2016, contingent upon the Company achieving certain performance objectives based on Adjusted EBITDA (earnings before interest, taxes, depreciation, and amortization of identifiable intangible assets, but excluding gains, losses or expenses associated with unusual items such as equity-based compensation expense, impairment charges and acquisition related costs) during 2013. OnMarch 4, 2013, the CEO was awarded a performance-based award which had a grant date fair market value of $1.0 million. The number of shares will be determined by dividing $0.5 million by the closing price of the Company’s stock on each of February 1, 2014 and February 1, 2015, contingent upon the Company meeting certain financial performance objectives during 2013. The Company classifies this award as a liability award until the number of shares is determined. The grant-date fair market value of the RSUs described in this paragraph is expensed over the vesting term, based on an estimate of the percentage achievement of the applicable performance targets. All awards are subject to the CEO’s continued employment through applicable vesting dates. All awards may vest on an accelerated basis in part or in full upon the occurrence of certain events.

In the first quarter of 2013, the Company granted RSUs to certain other executive officers with an aggregate grant-date fair value of $2.0 million. Of the $2.0 million, $1.0 million will vest in three equal annual increments subject to continued employment on each succeeding grant-date anniversary. The remaining $1.0 million vests on January 2, 2014, subject to continued employment and the Company attaining certain performance objectives during 2013, as approved by the Compensation Committee. Compensation expense for the performance-based component of these awards is recognized over the vesting period, based on an estimate of the percentage achievement of the targets for these awards.

In the second quarter of 2013, the Company granted RSUs to certain executive officers. The aggregate grant-date fair value of these grants was $0.9 million. Of the $0.9 million, $0.5 million will vest in three equal annual increments subject to continued employment on each succeeding grant-date anniversary; $0.3 million will vest on May 31, 2014, subject to continued employment, attaining certain performance objectives and certification by the Compensation Committee; and the remaining $0.1 million will vest on January 2, 2014, subject to continued employment, attaining certain performance objectives and certification by the Compensation Committee. Compensation expense for the performance-based component of these awards is recognized over the vesting period, based on an estimate of the percentage achievement of the targets for these awards.

On May 15, 2013, the Company granted 99,900 RSUs with an aggregate grant-date fair value of $2.6 million to certain Apex employees. The time-based portion of the grants, 39,958 RSUs, begins to vest on the first anniversary of the grant date and in eight quarterly installments thereafter, subject to continued employment. The performance-based portion of the grants, 59,942 RSUs, will vest, if the performance objective is attained, in 12 equal installments beginning on April 1, 2014 and on each quarterly anniversary thereafter, subject to continued employment through each vesting date.

On March 30, 2013 the Company issued104,328shares of common stock under the On Assignment 2010 Employee Stock Purchase Plan (the "ESPP"). On September 30, 2013 the Company issued98,872shares of common stock under theESPP. 

Compensation expense related to stock-based compensation, including the ESPP, was $4.2 million and $3.1 million for the three months endedSeptember 30, 2013 and 2012. Compensation expense related to stock-based compensation, including the ESPP, was $10.2 million and $6.5 million for the nine months endedSeptember 30, 2013 and 2012, respectively. Stock-based compensation is included in the Condensed Consolidated Statements of Operations and Comprehensive Income in selling, general and administrative expenses.