Stock-Based Compensation

Under the 2013 Equity Incentive Plan, as amended, we are authorized to grant 3.3 million restricted stock units or performance stock units of our common stock as incentive stock awards. At December 31, 2018, 1.2 million shares were available for future issuance under the 2013 Equity Incentive Plan.

Restricted Stock Units—We incur stock-based compensation expense in connection with restricted stock units awarded to employees of Ashford LLC, included in “advisory services fee,” on our consolidated statements of operations, employees of Remington Lodging, included in “management fees” on our consolidated statements of operations and common stock issued to our independent directors, which immediately vests, and is included in “corporate general and administrative” expense on our consolidated statements of operations.

At December 31, 2018, the unamortized cost of the unvested shares of restricted stock was $3.9 million, which is expected to be recognized over a period of 2.8 years with a weighted average period of 2.2 years and have vesting dates between March 2019 and November 2021.

The following table summarizes the stock-based compensation expense for restricted stock units (in thousands):



	Year Ended December 31,
Line Item	2018		2017		2016
Advisory services fee	$	2,277	$	916	$	597
Management fees	219		92		71
Corporate general and administrative	243		201		227
	$	2,739	$	1,209	$	895

For the year ended December 31, 2018, approximately $640,000 of the compensation expense was related to the accelerated vesting of equity awards granted to one of our executive officers upon his death, in accordance with the terms of the awards.

A summary of our restricted stock activity is as follows (shares in thousands):



	Year Ended December 31,
	2018				2017				2016
	Restricted Shares		Weighted Average Price at Grant		Restricted Shares		Weighted Average Price at Grant		Restricted Shares		Weighted Average Price at Grant
Outstanding at beginning of year	420		$	11.87	360		$	12.90	140		$	16.01
Restricted shares granted	257		9.90		198		10.78		309		12.34
Restricted shares vested	(229	)	11.54		(131	)	13.05		(84	)	15.98
Restricted shares canceled	(7	)	10.50		(7	)	11.81		(5	)	13.82
Outstanding at end of year	441		$	10.91	420		$	11.87	360		$	12.90

Performance Stock Units— The compensation committee of the board of directors of the Company approves the issuance of grants of PSUs to certain executive officers from time to time. The award agreements provide for the grant of a target number of PSUs that will be settled in shares of common stock of the Company, if and when the applicable vesting criteria have been achieved following the end of the performance and service period, generally three years from the issuance date. The target number of PSUs may be adjusted from 0% to 200% based on achievement of a specified relative total stockholder return based on the formula determined by the Company’s Compensation Committee on the grant date. The performance criteria for the PSUs are based on market conditions under the relevant literature, and the PSUs were granted to non-employees. Upon the adoption of ASU 2018-07, the corresponding compensation cost is recognized ratably over the service period for the award as the service is rendered, based on the grant date fair value of the award, regardless of the actual outcome of the market condition as opposed to being accounted for at fair value based on the market price of the shares at each quarterly measurement date.

The following table summarizes the compensation expense for PSUs (in thousands):



	Year Ended December 31,
Line Item	2018		2017			2016
Advisory services fee	$	2,443	$	(1,375	)	$	813

During the year ended December 31, 2018, approximately $1.6 million of the compensation expense was related to the accelerated vesting of PSUs granted to one of our executive officers upon his death, in accordance with the terms of the awards.

As of December 31, 2018, we had unamortized compensation expense of $2.0 million related to PSUs which is expected to be recognized over a period of 2.0 years with a weighted average period of 1.7 years.

A summary of our PSU activity is as follows (shares in thousands):



	Year Ended December 31,
	2018				2017				2016
	PSUs		Weighted Average Price at Grant		PSUs		Weighted Average Price at Grant		PSUs	Weighted Average Price at Grant
Outstanding at beginning of year	381		$	11.97	417		$	14.80	155	$	18.40
PSUs granted	197		13.43		119		10.42		262	12.67
PSUs canceled	(262	)	12.67		(155	)	18.40		—	—
Outstanding at end of year	316		$	12.29	381		$	11.97	417	$	14.80