Stock Based Compensation (Tables)

6 Months Ended

Jun. 30, 2020

Equity [Abstract]

Summary of Stock Option Activity

A summary of the stock option activity under the Company’s plans for the six months ended June 30, 2020 is as follows:

	Number of Shares	Weighted Average Exercise Price
Options outstanding at December 31, 2019	5,318,759	$	9.97
Options granted	816,428	$	28.09
Less:
Options exercised	691,299	$	7.42
Options forfeited	57,659	$	14.72
Options outstanding at June 30, 2020	5,386,229	$	13.01
Exercisable at June 30, 2020	3,101,808	$	8.66

Summary of Fair Value of Each Stock Option Award Granted

The fair value of each stock option award granted during the six months ended June 30, 2020 was estimated as of the grant date using a trinomial lattice model with the following weighted average assumptions:

	Six Months Ended June 30, 2020
Expected term (in years)	4.0 - 5.5
Risk-free interest rate (%)	0.7%
Expected volatility (%)	39.9% - 44.5%
Dividend yield (%)	—
Weighted average fair value/share at grant date	$8.81

Summary of Restricted Stock Activity

A summary of the restricted stock activity under the Company’s plans for the six months ended June 30, 2020 is as follows:

	Number of Restricted Shares	Weighted Average Grant Date Fair Value
Nonvested at December 31, 2019	335,298	$	15.75
Granted	143,177	$	28.15
Vested	(166,836)	$	12.81
Forfeited	(4,919)	$	20.34
Nonvested at June 30, 2020	306,720	$	23.06