Our 2018 Equity Incentive Plan (the “Plan”) was approved by stockholders in May 2018. The Plan authorizes us to issue up to 4.35 million shares of common stock, along with non-qualified stock options, stock appreciation rights, restricted stock and performance units to our officers, key employees, non-employee directors and consultants. At March 31, 2021, there were 0.3 million shares available for future grants under this Plan. No more than 1.2 million shares may be used under the Plan as “full value” awards, which include restricted stock and performance units. The Company’s Board of Directors has approved, subject to shareholder approval at the May 25, 2021 annual meeting of shareholders, an increase of 2.0 million in the shares authorized under the Plan and elimination of the 1.2 million limit on “full value” shares. It is our policy to issue shares from authorized but not issued shares upon the exercise of stock options.

Under the terms of the Plan, each year eligible participants are granted time value restricted stock units (“RSUs”), vesting ratably over a three-year period, and performance restricted stock units (“PSUs”), with three-year cliff vesting. Upon vesting, each restricted stock award is exchangeable for one share of the Company’s common stock, with accrued dividends.

On May 16, 2019 the Company granted the following equity awards to our then new President and Chief Executive Officer in connection with the 2019 Inducement Grant Plan (the “Inducement Plan”): (i) an initial award consisting of (a) 666,667 PSUs at target, vesting in three approximately equal installments, to the extent the performance metrics are satisfied, during each of three performance periods and (b) 333,333 RSUs, vesting in approximately equal installments on February 28, 2020, 2021 and 2022; (ii) a 2019-2021 PSU grant, with the target number of 316,832 PSUs, which will vest to the extent the performance metrics are satisfied; and (iii) a 2019 RSU grant of 158,416 RSUs, vesting in approximately equal installments on February 28, 2020, 2021 and 2022. The PSU awards may be earned at up to 200 percent of target depending on the level of achievement of the performance metrics.

Restricted stock unit and restricted performance stock unit activity for the three months ended March 31, 2021 is summarized in the following table:

	Equity Incentive Awards
	Restricted Stock Units			Weighted Average Grant Date Fair Value		Performance Shares			Weighted Average Grant Date Fair Value		Options		Weighted Average Exercise Price
Balance at December 31, 2020		1,213,667		$	3.59		2,176,290		$	4.88		24,000	$	20.39
Granted		1,787			5.41		21,352			5.67		—		—
Settled		(388,504	)		4.05		(193,778	)		5.45		—		—
Forfeited or expired		(31,092	)		8.25		(142,769	)		12.96		—		—
Balance at March 31, 2021		795,858		$	3.19		1,861,095		$	6.05		24,000	$	20.39

Awards estimated to vest in the future		724,142		$	3.16		1,341,900		$	6.09		24,000	$	20.39

Stock-based compensation expense was $1.8 million for the three months ended March 31, 2021, as compared to income of $0.2 million for the three months ended March 31, 2020. The higher expense for the three months ended March 31, 2021 was attributable to modification of the 2019 and 2020 PSU awards, substituting budgeted amounts for actual performance for the second quarter of 2020 (one of twelve quarters in the respective performance periods), to offset the impact of COVID-19. The modification increased stock-based compensation for the three months ended March 31, 2021 by $1.1 million. The income for the three months ended March 31, 2020 was due to a reversal of $1.2 million of previously accrued expense due to the reduction of our estimates regarding the achievement of the performance metric, to zero, in light of the global pandemic. Unrecognized stock-based compensation expense related to non-vested awards of $8.4 million is expected to be recognized over a weighted average period of approximately 1.5 years as of March 31, 2021.