5. Goodwill and Intangible Assets

The following table presents the changes in our goodwill balance (in thousands):


Balance at December 31, 2018	$	19,435
Foreign currency impact		(29)
Balance at September 30, 2019	$	19,406

We have two reporting units, Marketplaces and Media. Goodwill related to our Marketplaces reporting unit was $17.1 million as of September 30, 2019. Goodwill related to our Media reporting unit was $2.3 million and was recorded in connection with the acquisition of Well+Good in June 2018. Refer to Note 12 for additional information regarding our acquisition of Well+Good.

Intangible assets consisted of the following (in thousands):


	September 30, 2019
	Gross carrying		Accumulated		Net carrying
	amount		amortization		amount
Customer relationships	$	4,003	$	(2,861)	$	1,142
Artist relationships		12,216		(11,250)		966
Media content		91,489		(91,319)		170
Technology		6,204		(6,110)		94
Non-compete agreements		25		(25)		—
Trade names		18,238		(7,302)		10,936
	$	132,175	$	(118,867)	$	13,308


	December 31, 2018
	Gross carrying		Accumulated		Net carrying
	amount		amortization		amount
Customer relationships	$	4,003	$	(2,219)	$	1,784
Artist relationships		12,223		(11,007)		1,216
Media content		91,489		(91,215)		274
Technology		6,204		(5,682)		522
Non-compete agreements		25		(25)		—
Trade names		16,257		(6,120)		10,137
	$	130,201	$	(116,268)	$	13,933

Identifiable finite-lived intangible assets are amortized on a straight-line basis over their estimated useful lives commencing on the date that the asset is available for its intended use.

Total amortization expense for the periods shown below includes (in thousands):


	Three months ended September 30,				Nine months ended September 30,
	2019		2018		2019		2018
Service costs	$	17	$	220	$	105	$	889
Sales and marketing		288		326		892		646
Product development		104		184		428		769
General and administrative		398		403		1,194		811
Total amortization	$	807	$	1,133	$	2,619	$	3,115