Stockholders' Equity

3 Months Ended

Mar. 31, 2017

Equity [Abstract]

Stockholders' Equity

Stockholders’ Equity

The Company grants options and awards to employees and non-employee directors pursuant to a stockholder approved stock incentive plan, which is described in further detail in Note 8, Stockholders' Equity, of Notes to Consolidated Financial Statements in the Company's Annual Report on Form 10-K for the fiscal year ended December 31, 2016.

The following is a summary of the Company’s stock option and restricted stock activity and related information:

	Stock Options				Restricted Stock Awards
	Shares		Weighted- Average Exercise Price		Shares		Weighted- Average Grant Date Fair Value
Balance as of December 31, 2016	1,754,275		$	42.12	308,700		$	86.61
Granted	180,765		100.81		64,155		100.91
Exercised	(29,412	)	17.42		(96,744	)	79.68
Forfeited	—		—		(300	)	97.92
Balance as of March 31, 2017	1,905,628		$	48.07	275,811		$	92.36

As of March 31, 2017, outstanding options to purchase 1.3 million shares were exercisable with a weighted average exercise price per share of $33.06.

Employee Stock Purchase Plan

The price at which common stock is purchased under the Amended ESPP is equal to 85% of the fair market value of the common stock on the first or last day of the offering period, whichever is lower. During the three months ended March 31, 2017, approximately 829 shares were issued under the Amended ESPP. As of March 31, 2017, 70,297 shares were available for future purchases under the Amended ESPP.