|3 Months Ended|
Mar. 31, 2018
|Disclosure of Compensation Related Costs, Share-based Payments [Abstract]|
|Stock-Based Compensation and Employee Benefit Plans||
Stock-Based Compensation and Employee Benefit Plans
Employee Stock-Based Benefit Plans
At March 31, 2018, the Company had stock-based compensation awards outstanding under the following plans: the 2004 Stock Plan, the 2010 Equity Incentive Plan, as amended, or 2010 Plan, the 2010 Employee Stock Purchase Plan, or ESPP, and plans under which equity incentive awards were assumed in connection with the acquisitions of Entropic in 2015 and Exar Corporation in 2017. Refer to the Company’s Annual Report for a summary of the Company's stock-based compensation and equity plans as of December 31, 2017. There have been no material changes to the terms of the Company's equity incentive plans during the three months ended March 31, 2018. All current stock awards are issued under the 2010 Plan and ESPP.
As of March 31, 2018, the number of shares of common stock reserved for issuance under the 2010 Plan was 13,874,903 shares. As of March 31, 2018, the number of shares of common stock reserved for issuance under the ESPP was 2,406,646 shares.
The Company recognizes stock-based compensation in the consolidated statements of income, based on the department to which the related employee reports, as follows:
The total unrecognized compensation cost related to unvested restricted stock units and restricted stock awards as of March 31, 2018 was $47.7 million, and the weighted average period over which these equity awards are expected to vest is 2.33 years. The total unrecognized compensation cost related to unvested stock options as of March 31, 2018 was $5.5 million, and the weighted average period over which these equity awards are expected to vest is 1.75 years.
Restricted Stock Units and Restricted Stock Awards
The Company calculates the fair value of restricted stock units based on the fair market value of the Company's common stock on the grant date. Stock based compensation is recognized over the vesting period using the straight-line method.
A summary of the Company’s restricted stock unit and restricted stock award activity is as follows:
Employee Stock Purchase Rights and Stock Options
The Company uses the Black-Scholes valuation model to calculate the fair value of employee stock purchase rights and stock options granted to employees. Stock based compensation expense is recognized over the vesting period using the straight-line method.
Employee Stock Purchase Rights
During the three months ended March 31, 2018, there were no shares of common stock purchased under the ESPP.
The fair values of employee stock purchase rights were estimated using the Black-Scholes option pricing model at their respective grant date using the following assumptions:
The risk-free interest rate assumption was based on the United States Treasury’s rates for U.S. Treasury zero-coupon bonds with maturities similar to those of the expected term of the award being valued. The assumed dividend yield was based on the Company’s expectation of not paying dividends in the foreseeable future. The expected term is the duration of the offering period for each grant date. In addition, the estimated volatility incorporates the historical volatility over the expected term based on the Company's daily closing stock prices.
A summary of the Company’s stock options activity is as follows:
No stock options were granted by the Company during the three months ended March 31, 2018.
The intrinsic value of stock options exercised was $2.1 million and $1.9 million in the three months ended March 31, 2018 and 2017, respectively. Cash received from exercise of stock options was $1.0 million and $0.4 million during the three months ended March 31, 2018 and 2017, respectively. The tax benefit from stock options exercised was $2.1 million and $0.3 million during the three months ended March 31, 2018 and 2017, respectively.
Employee Incentive Bonus
The Company settles a majority of bonus awards for its employees, including executives, in shares of common stock under the 2010 Equity Incentive Plan. When bonus awards are settled in common stock issued under the 2010 Equity Incentive Plan, the number of shares issuable to plan participants is determined based on the closing price of the Company's common stock as determined in trading on the New York Stock Exchange on a date approved by the Board of Directors. In connection with the Company's bonus programs, in February 2018, the Company issued 0.3 million freely-tradable shares of the Company's common stock in settlement of bonus awards to employees, including executives, for the 2017 performance period. At March 31, 2018, the Company has an accrual of $1.8 million for bonus awards for employees for year-to-date achievement in the 2018 performance period. The Company's compensation committee retains discretion to effect payment in cash, stock, or a combination of cash and stock.
The entire disclosure for compensation-related costs for equity-based compensation, which may include disclosure of policies, compensation plan details, allocation of equity compensation, incentive distributions, equity-based arrangements to obtain goods and services, deferred compensation arrangements, employee stock ownership plan details and employee stock purchase plan details.
Reference 1: http://www.xbrl.org/2003/role/presentationRef