Stock-Based Compensation Plans (Tables)

9 Months Ended

Sep. 30, 2020

Share-based Payment Arrangement, Noncash Expense [Abstract]

Schedule of components of stock compensation expense

The components of stock-based compensation expense were as follows:

	Three months ended September 30,				Nine Months Ended September 30,
	2020		2019		2020		2019
	(in thousands)				(in thousands)
2007 Stock Incentive Plan	$	707	$	1,099	$	2,435	$	3,501
2018 Stock Incentive Plan	2,329		1,071		5,626		2,046
Employee Stock Purchase Plan	77		31		184		41
Total Stock Compensation Expense	$	3,113	$	2,201	$	8,245	$	5,588

Summary of restricted stock activity

The following table summarizes restricted stock activity under the 2007 and 2018 Plans during the nine months ended September 30, 2020:

	Shares
Balance as of December 31, 2019	505,467
Shares granted	307,600
Shares forfeited	—
Shares vested	(229,414)
Balance as of September 30, 2020	583,653