Long-Term Incentive Plan Units

LTIP Units held pursuant to the Company's incentive plans are generally exercisable by the holder at any time after vesting. Each unit is convertible into one common share. Costs associated with the LTIP Units issued under the Company's incentive plans are measured as of the grant date and expensed ratably over the vesting period. Total expense associated with LTIP Units issued under the Company's incentive plans for each of the years ended December 31, 2017, 2016, and 2015 was $0.4 million.

On September 12, 2017, The Company's Board of Directors authorized the issuance of 10,002 LTIP Units to its independent directors pursuant to the Company's 2017 Equity Incentive Plan. These LTIP Units will vest and become non-forfeitable on September 11, 2018.

On December 12, 2017, the Company's Board of Directors authorized the issuance of 14,419 LTIP Units to certain of its partially dedicated employees pursuant to the Company's 2017 Equity Incentive Plan. These LTIP Units will vest and become non-forfeitable on December 12, 2018 with respect to 8,533 LTIP Units and December 12, 2019 with respect to 5,886 LTIP Units.

The below table details on the Company's unvested LTIP Units as of December 31, 2017:



Grant Recipient	Number of LTIP Units Granted	Grant Date	Vesting Date⁽¹⁾
Independent directors:
	10,002	September 12, 2017	September 11, 2018
Partially dedicated employees:
	8,533	December 12, 2017	December 12, 2018
	5,886	December 12, 2017	December 12, 2019
	5,583	December 13, 2016	December 13, 2018
Total unvested LTIP Units at December 31, 2017	30,004


(1)	Date at which such LTIP Units will vest and become non-forfeitable.

The following table summarizes issuance and exercise activity of the Company's LTIP Units for the years ended December 31, 2017, 2016, and 2015:



	Year Ended December 31, 2017					Year Ended December 31, 2016					Year Ended December 31, 2015
	Manager	Director/ Employee		Total		Manager	Director/ Employee		Total		Manager	Director/ Employee		Total
LTIP Units Outstanding (12/31/2016, 12/31/2015, and 12/31/2014, respectively)	375,000	94,539		469,539		375,000	74,938		449,938		375,000	54,314		429,314
Granted	—	24,421		24,421		—	22,076		22,076		—	22,571		22,571
Exercised	—	(2,801	)	(2,801	)	—	(2,475	)	(2,475	)	—	(1,947	)	(1,947	)
LTIP Units Outstanding (12/31/2017, 12/31/2016, and 12/31/2015, respectively)	375,000	116,159		491,159		375,000	94,539		469,539		375,000	74,938		449,938
LTIP Units Vested and Outstanding (12/31/2017, 12/31/2016, and 12/31/2015, respectively)	375,000	86,155		461,155		375,000	65,828		440,828		375,000	46,120		421,120

As of December 31, 2017, there were an aggregate of 1,907,769 common shares underlying awards, including LTIP Units, available for future issuance under the Company's 2017 Equity Incentive Plan.