The carrying amount and accumulated amortization of intangible assets as of and were as follows (in thousands):

 

		2019
		Gross Assets				Accumulated Amortization				Net
Nonamortizable intangible assets
Trade names		$	2,000			$	-			$	2,000
Amortizable intangible assets
Trade names			23				(23	)			-
Physician and customer relationships			36,534				(26,550	)			9,984
Software			11,230				(7,751	)			3,479
Total nonamortizable and amortizable intangible assets		$	49,787			$	(34,324	)		$	15,463

 

		2018
		Gross Assets				Accumulated Amortization				Net
Nonamortizable intangible assets
Trade names		$	2,000			$	-			$	2,000
Amortizable intangible assets
Trade names			23				(23	)			-
Physician and customer relationships			36,534				(24,175	)			12,359
Software			11,230				(5,724	)			5,506
Total nonamortizable and amortizable intangible assets		$	49,787			$	(29,922	)		$	19,865

 

The weighted average remaining lives of physician and customer relationships and software were -years and -year, respectively, as of

 

The Company assesses impairment indicators related to its internally-developed, internal-use software, specifically looking at the effectiveness and useful lives of each project and sub-project to determine if impairment indicators are present. In and respectively, the Company assessed the impairment indicators and found to be present.

 

Amortization expense for intangible assets for the years ended and was million and million, respectively, which was recorded in operating expenses. Expected annual amortization expense for the next years for intangible assets recorded as of is as follows (in thousands):

 

		2020				2021				2022				2023				2024				2025 and thereafter
Amortization expense		$	4,285			$	3,930			$	2,051			$	548			$	548			$	2,101