Stock-Based Compensation

12 Months Ended

Dec. 31, 2020

Share-based Payment Arrangement [Abstract]

Incentive Award Plan

Effective as of June 19, 2015, the Company's Board adopted the Incentive Award Plan, under which the Company may grant cash and equity incentive awards to eligible employees, directors, and consultants. Time-based RSU awards granted to employees vest equally on each of the first three anniversaries of the applicable vesting commencement date, and time-based RSU awards granted to directors vest on the earlier of the one-year anniversary of the applicable grant date or the date of the Company's next annual meeting of its shareholders following the grant date, subject to the recipients' continued service to the Company. Performance-based RSU awards granted to employees vest on the third anniversary subsequent to the grant date, subject to the recipients' continued service to the Company and achievement of the specified performance levels.

Under the Incentive Award Plan, the Company is authorized to grant up to 30,000,000 shares of the Company's common stock pursuant to awards under the Incentive Award Plan. As of December 31, 2020, 18,329,901 shares were available for future issuance under the Incentive Award Plan.

The following table summarizes the Company's RSU activity under the Incentive Award Plan during the years ended December 31, 2020, 2019 and 2018:


	Unvested Time-Based RSUs	Unvested Performance-Based RSUs	Weighted Average Grant Date Value Per Share (a)
Outstanding as of January 1, 2018	1,535,505	—	$3.19
Shares granted	1,950,307	—	$3.14
Shares vested	(1,349,852)	—	$3.20
Shares forfeited	(587,810)	—	$3.19
Outstanding as of December 31, 2018	1,548,150	—	$3.18

Shares granted	1,225,170	1,450,811	$3.14
Shares vested	(1,275,188)	—	$3.18
Shares forfeited	(202,441)	(61,169)	$3.17
Outstanding as of December 31, 2019	1,295,691	1,389,642	$3.14

Shares granted	1,255,793	2,484,346	$3.14
Shares vested	(1,144,343)	—	$3.14
Shares forfeited	(303,325)	(553,034)	$3.14
Outstanding as of December 31, 2020	1,103,816	3,320,954	$3.14

(a)On May 8, 2020, the board of directors approved a grant of time-based and performance-based RSUs under the Incentive Award Plan at the most recent estimated net asset value per share of $3.14 as of May 1, 2019. Periodically, the Company engages an independent third-party valuation advisory consulting firm to estimate the per share value of the Company's common stock.

As of December 31, 2020, there was $5,221 of total unrecognized compensation expense related to unvested stock-based compensation arrangements that will vest through December 2022. The Company recognized stock-based compensation expense of $4,449, $5,541 and $4,330 for the years ended December 31, 2020, 2019 and 2018, respectively, as a part of general and administrative expenses on the consolidated statements of operations and comprehensive (loss) income.