Stockholder's Equity (Tables)

6 Months Ended

Jun. 30, 2019

Equity [Abstract]

Share Grants Activity

The following table represents the share grants activity for the six months ended June 30, 2019: 

	Restricted stock				Options
	Number of shares		Weighted average grant date fair value		Number of shares		Weighted average grant date fair value
Share grants outstanding as of December 31, 2018	574,285		$	49.68	161,807		$	38.08
Granted	159,845		$	109.29	—		$	—
Vested or exercised	(191,707	)	$	43.71	(47,680	)	$	35.55
Share grants outstanding as of June 30, 2019	542,423		$	68.81	114,127		$	39.59

Shares of Common Stock Issued Under Employee Stock Purchase Plan

The table below details the shares of common stock issued during 2019: 

	Number of shares	Per share price
Shares available as of December 31, 2018	152,344
Shares issued during the three months ended March 31, 2019	5,357	$	89.19
Shares issued during the three months ended June 30, 2019	4,301	$	105.36
Shares available as of June 30, 2019	142,686