7. Intangible assets

The following table sets forth the changes in our intangible assets balance, for all periods presented:

	Intangible Assets
Balance, December 31, 2015	$	16,055
Additions		1,210
Amortization expense		(3,470	)
Impairment loss		(12	)

Balance, December 31, 2016		13,783
Amortization expense		(3,520	)

Balance, December 31, 2017	$	10,263

In November 2016, we acquired a caching technology intangible asset for $1,250 which was valued at the date of acquisition based on Level 3 inputs. $1,150 of the purchase price was paid in January 2017. The identifiable intangible asset was valued at fair value at $1,210 using the cost savings and replacement cost methods using a discount rate of 20%. The remaining purchase price was expensed as it related to the settlement of a pre-existing contractual relationship. The caching technology has an estimated useful life of 4 years.

During 2016 we recorded impairment losses for certain patent applications that we abandoned.

Intangible assets at December 31, 2017 consist of the following:

	Historical Cost		Accumulated Amortization			Net
Venue contracts	$	22,061	$	(13,835	)	$	8,226
Non-compete agreements		3,590		(2,992	)		598
Technology		2,410		(1,265	)		1,145
Patents, trademarks and other		844		(550	)		294

	$	28,905	$	(18,642	)	$	10,263

Intangible assets at December 31, 2016 consist of the following:

	Historical Cost		Accumulated Amortization			Net
Venue contracts	$	23,601	$	(13,276	)	$	10,325
Non-compete agreements		3,590		(2,274	)		1,316
Technology		3,520		(1,742	)		1,778
Advertiser relationships		70		(62	)		8
Patents, trademarks and other		1,034		(678	)		356

	$	31,815	$	(18,032	)	$	13,783

The decrease in our intangible assets cost and accumulated amortization balances from 2016 to 2017 related to the write-off of intangible assets that have expired.

Amortization expense for fiscal years 2018 through 2022 and thereafter is as follows:

Year	Amortization Expense
2018	$	2,674
2019		1,937
2020		1,832
2021		1,455
2022		1,261
Thereafter		1,104

	$	10,263