Share-Based Compensation (Tables)

6 Months Ended

Jun. 30, 2021

The table below presents the number of RSUs granted, the average grant-date fair value and the number of shares vested for the following periods:


	Six Months Ended June 30,
	2021	2020
RSUs granted	118,223	223,882
Average grant-date fair value	$13.84	$2.78
Issued upon vesting, net to shares withheld for income taxes	105,038	36,174

The table below presents the number of PRSUs granted and the number of shares vested for the following periods:


	Six Months Ended June 30,
	2021	2020
PRSUs granted 1	282,706	87,899
Average grant-date fair value 2	$13.63	—
Issued upon vesting, net to shares withheld for income taxes	6,800	3,895

The ranges for the assumptions used in the Monte Carlo model for these PRSUs granted during 2021, 2020 and 2019 are presented as follows:


	2021		2020		2019
Monte Carlo grant date fair value	$17.74 to $33.31		$2.40 to $16.02		$34.02
Expected volatility	131.74% to 134.74%		101.32% to 117.71%		49.9	%
Dividend yield	0.0	%	0.0	%	0.0	%
Risk-free interest rate	0.22% to 0.29%		0.18% to 0.51%		1.66	%
Performance period	2021-2023		2020-2022		2020-2022