Stock-Based Compensation

3 Months Ended

Mar. 31, 2020

Share-based Payment Arrangement [Abstract]

In March 2014, the Company's board of directors approved the 2014 Equity Incentive Plan, or 2014 Plan, under which stock options, stock appreciation rights, restricted stock, restricted stock units, performance shares and units and other cash-based or stock-based awards may be granted to employees, consultants and directors. Shares of common stock that are issued and available for issuance under the 2014 Plan consist of authorized, but unissued or reacquired shares of common stock or any combination thereof.

As of December 31, 2019, a total of 11,145 shares had been reserved for issuance under the 2014 Plan. The 2014 Plan contains a provision that automatically increases the shares available for issuance under the plan on January 1 of each year subsequent to the 2014 Plan's adoption through 2024, by an amount equal to the smaller of (a) 4.5% of the number of shares of common stock issued and outstanding on the immediately preceding December 31, or (b) an amount determined by the Company's board of directors. On January 1, 2020, 2,177 shares were added to the 2014 Plan in accordance with the annual automatic increase provision of the 2014 Plan. In addition, the 2014 Plan reserve is automatically increased to include any shares issuable upon expiration or termination of options granted under the Company's 2007 Stock Plan, or 2007 Plan, for options that expire or terminate without having been exercised. For the three months ended March 31, 2020, no shares have been transferred to the 2014 Plan from the 2007 Plan, and as of March 31, 2020 a total of 13,322 shares were allocated for issuance under the 2014 Plan. As of March 31, 2020, options to purchase a total of 2,706 shares of common stock have been granted under the 2014 Plan, 5,203 shares have been reserved under the 2014 Plan for the vesting of restricted stock units and market stock units, 913 shares have been returned to the 2014 Plan as a result of termination of options that expired or terminated without having been exercised and restricted stock awards that terminated prior to the awards vesting, and 6,326 shares of common stock remain available for future issuance under the 2014 Plan.

In July 2007, the Company adopted the 2007 Plan under which options or stock purchase rights may be granted to employees, consultants and directors. Upon the completion of the Company's initial public offering, or IPO, in March 2014, the board of directors terminated the 2007 Plan in connection with the IPO and all shares that were available for future issuance under the 2007 Plan at such time were transferred to the 2014 Plan. The 2007 Plan will continue to govern the terms and conditions of all outstanding equity awards granted under the 2007 Plan. As of March 31, 2020, no shares remain available for future issuance under the 2007 Plan.

Stock Options

Stock option activity during the three months ended March 31, 2020 was as follows:



	Number of Options		Weighted Average Exercise Price
Balance as of January 1, 2020	1,419		$	23.61
Granted	—		—
Exercised	(136	)	10.66
Forfeited	—		—
Balance as of March 31, 2020	1,283		$	24.98

Restricted Stock Units

Restricted stock unit activity during the three months ended March 31, 2020 was as follows:



	Number of Shares		Weighted Average Grant Date Fair Value
Nonvested as of January 1, 2020	1,952		$	58.56
Granted	309		68.72
Vested	(296	)	50.92
Forfeited	(58	)	60.57
Nonvested as of March 31, 2020	1,907		$	61.64

Market Stock Units

Market stock unit activity during the three months ended March 31, 2020 was as follows:



	Number of Shares		Weighted Average Grant Date Fair Value
Nonvested as of January 1, 2020	434		$	28.85
Granted	131		30.16
Vested	(148	)	15.44
Forfeited	(24	)	29.97
Nonvested as of March 31, 2020	393		$	34.27